WO2020224560A1

WO2020224560A1 - Frequency selective uplink precoder indication

Info

Publication number: WO2020224560A1
Application number: PCT/CN2020/088537
Authority: WO
Inventors: Qiaoyu Li; Yu Zhang; Liangming WU; Chenxi HAO; Chao Wei; Hao Xu; Wanshi Chen; Peter Gaal
Original assignee: Qualcomm Incorporated
Priority date: 2019-05-03
Filing date: 2020-05-01
Publication date: 2020-11-12
Also published as: WO2020223834A1

Abstract

Methods, systems, and devices for wireless communications are described. A user equipment (UE) may receive, from a base station, a first stage uplink precoder indication of wideband uplink precoding. The UE may receive a second stage uplink precoder indication of a first wideband co-phase granularity for the wideband uplink precoding, a subband co-phase granularity for subband uplink precoding, or both. In some cases, each of the first wideband co-phase granularity and the subband co-phase granularity may be finer than a second wideband co-phase granularity indicated by the first stage uplink precoder indication. The UE may generate precoded information based on the first stage uplink precoder indication and the second stage uplink precoder indication and transmit a transmission generated based on the precoded information.

Description

FREQUENCY SELECTIVE UPLINK PRECODER INDICATION

CROSS REFERENCE

The present Application for Patent claims priority to International Patent Application No. PCT/CN2019/085422 to Li et al., titled “FREQUENCY SELECTIVE UPLINK PRECODER INDICATION, ” filed May 3, 2019, assigned to the assignee hereof, and expressly incorporated by reference in its entirety herein.

BACKGROUND

The following relates generally to wireless communications, and more specifically to frequency selective uplink precoder indication.

Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power) . Examples of such multiple-access systems include fourth generation (4G) systems such as Long Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, or LTE-A Pro systems, and fifth generation (5G) systems which may be referred to as New Radio (NR) systems. These systems may employ technologies such as code division multiple access (CDMA) , time division multiple access (TDMA) , frequency division multiple access (FDMA) , orthogonal frequency division multiple access (OFDMA) , or discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-S-OFDM) . A wireless multiple-access communications system may include a number of base stations or network access nodes, each simultaneously supporting communication for multiple communication devices, which may be otherwise known as user equipment (UE) .

A UE and a base station may communicate using beamformed transmissions. A UE may precode uplink information for enhanced uplink beamformed transmissions. The UE may select a precoder from a codebook stored in memory to precode the uplink information. Conventional techniques for uplink precoding are deficient.

SUMMARY

The described techniques relate to improved methods, systems, devices, and apparatuses that support frequency selective uplink precoder indication. Generally, the described techniques provide for a two stage uplink precoder indication. A base station may transmit a first stage uplink precoder indication and a second stage uplink precoder indication to a user equipment (UE) , where the second stage uplink precoder indication may support a frequency-selective uplink precoder indication, or a finer granularity precoder indication than the first stage uplink precoder indication, or both. The UE may precode uplink information to enhance uplink beamformed transmissions in accordance with the two stage uplink precoder indication. Different types of signaling for the second stage uplink precoder indication are described. For example, the base station may transmit the second stage uplink precoder indication via group common downlink control information (GC-DCI) . In some cases, the GC-DCI transmission may be used in addition to, or as an alternative to, Radio Resource Control (RRC) signaling. For example, the base station may configure multiple second stage uplink precoder configurations via RRC, then the base station may indicate, over DCI such as GC-DCI, which of the multiple second stage uplink precoder configurations the UE is to apply.

Additionally, techniques for generating (e.g., at a base station) and interpreting (e.g., at a UE) a payload for the second stage uplink precoder indication are described. A payload for the second stage uplink precoder indication may be configured based on which co-phase indication granularity criterion of a set of different co-phase indication granularity criteria the payload satisfies. Each of the different co-phase indication granularity criteria may correspond to a different case of co-phase indication granularity. The base station may generate the payload according to one of the different cases based on how granular the co-phase indication can be, given the payload size and other configured parameters. The UE may then determine which co-phase indication granularity criterion the payload satisfies and apply a corresponding payload interpretation rule to interpret the payload.

A method of wireless communications by a UE is described. The method may include receiving a first stage uplink precoder indication of wideband uplink precoding, receiving a second stage uplink precoder indication of a first wideband co-phase granularity for the wideband uplink precoding, a subband co-phase granularity for subband uplink precoding, or both, each of the first wideband co-phase granularity and the subband co-phase granularity being finer than a second wideband co-phase granularity indicated by the first stage uplink precoder indication, generating precoded information based on the first stage uplink precoder indication and the second stage uplink precoder indication, and transmitting a transmission generated based on the precoded information.

An apparatus for wireless communications by a UE is described. The apparatus may include a processor, memory in electronic communication with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to receive a first stage uplink precoder indication of wideband uplink precoding, receive a second stage uplink precoder indication of a first wideband co-phase granularity for the wideband uplink precoding, a subband co-phase granularity for subband uplink precoding, or both, each of the first wideband co-phase granularity and the subband co-phase granularity being finer than a second wideband co-phase granularity indicated by the first stage uplink precoder indication, generate precoded information based on the first stage uplink precoder indication and the second stage uplink precoder indication, and transmit a transmission generated based on the precoded information.

Another apparatus for wireless communications by a UE is described. The apparatus may include means for receiving a first stage uplink precoder indication of wideband uplink precoding, receiving a second stage uplink precoder indication of a first wideband co-phase granularity for the wideband uplink precoding, a subband co-phase granularity for subband uplink precoding, or both, each of the first wideband co-phase granularity and the subband co-phase granularity being finer than a second wideband co-phase granularity indicated by the first stage uplink precoder indication, generating precoded information based on the first stage uplink precoder indication and the second stage uplink precoder indication, and transmitting a transmission generated based on the precoded information.

A non-transitory computer-readable medium storing code for wireless communications by a UE is described. The code may include instructions executable by a processor to receive a first stage uplink precoder indication of wideband uplink precoding, receive a second stage uplink precoder indication of a first wideband co-phase granularity for the wideband uplink precoding, a subband co-phase granularity for subband uplink precoding, or both, each of the first wideband co-phase granularity and the subband co-phase granularity being finer than a second wideband co-phase granularity indicated by the first stage uplink precoder indication, generate precoded information based on the first stage uplink precoder indication and the second stage uplink precoder indication, and transmit a transmission generated based on the precoded information.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for identifying a resource for transmitting the transmission.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, identifying the resource may include operations, features, means, or instructions for receiving control signaling that configures the UE with the resource for transmitting the transmission.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving control signaling that includes the first stage uplink precoder indication and the second stage uplink precoder indication.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving DCI that includes the first stage uplink precoder indication and the second stage uplink precoder indication.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, receiving the first stage uplink precoder indication and the second stage uplink precoder indication may include operations, features, means, or instructions for receiving first DCI that includes the first stage uplink precoder indication and second DCI that includes the second stage uplink precoder indication.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, receiving the first stage uplink precoder indication and the second stage uplink precoder indication may include operations, features, means, or instructions for receiving an RRC configuration that includes the first stage uplink precoder indication and DCI that includes the second stage uplink precoder indication.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving DCI that schedules the UE to transmit the transmission.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the DCI includes the first stage uplink precoder indication and the second stage uplink precoder indication.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the DCI includes the first stage uplink precoder indication and second DCI includes the second stage uplink precoder indication.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving control signaling that configures the UE with a group temporary identifier and a search offset, and monitoring a search space for the second stage uplink precoder indication based on the group temporary identifier and the search offset.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, receiving the control signaling further may include operations, features, means, or instructions for receiving the control signaling that configures the UE with a set of different second stage uplink precoder configurations, decoding the search space to obtain DCI based on the group temporary identifier and the search offset, and selecting a first configuration from the set of different second stage uplink precoder configurations based on the DCI, where the precoded information may be generated based on the first configuration.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, receiving the control signaling further may include operations, features, means, or instructions for receiving the control signaling that configures the UE with a set of different second stage uplink precoder configurations and a set of indexes respectively associated with the set of different second stage uplink precoder configurations, decoding the search space to obtain DCI and a first index of the set of indexes based on the group temporary identifier and the search offset, and selecting a first configuration from the set of different second stage uplink precoder configurations based on the DCI and the first index, where the precoded information may be generated based on the first configuration.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for identifying a payload size for a payload of the second stage uplink precoder indication, a minimum wideband co-phase indication granularity, a minimum subband co-phase indication granularity, and a number of subbands for frequency selective co-phase indication, determining that the payload satisfies a co-phase indication granularity criterion based on the payload size, the number of subbands, and one or both of the minimum wideband co-phase indication granularity and the minimum subband co-phase indication granularity, and applying a payload interpretation rule corresponding to the co-phase indication granularity criterion to interpret the payload of the second stage uplink precoder indication.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, determining that the payload satisfies the co-phase indication granularity criterion may include operations, features, means, or instructions for applying, sequentially or in parallel, a respective co-phase indication granularity criterion of a set of different co-phase indication granularity criteria to determine that a first co-phase indication granularity criterion of the set of different co-phase indication granularity criteria may be satisfied, where the first co-phase indication granularity criterion corresponds to the payload interpretation rule.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the identifying further may include operations, features, means, or instructions for identifying a set of parameters including one or more of the payload size for the payload of the second stage uplink precoder indication, the minimum wideband co-phase indication granularity, the minimum subband co-phase indication granularity, and the number of subbands for frequency selective co-phase indication, where the identifying may be based on at least one predefinition for one or more parameters of the set of parameters stored in a storage device of the UE, receiving an RRC configuration indicating one or more parameters of the set of parameters, receiving DCI indicating one or more parameters of the set of parameters, or any combination thereof.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the co-phase indication granularity criterion may be that, using bits of the payload, the subband co-phase granularity at least satisfies the minimum subband co-phase indication granularity for each subband of a set of subbands, and where the payload interpretation rule may be that the subband co-phase granularity for each subband of the set of subbands may be indicated using respective bit subsets of the payload each having an equal number of bits that indicate a subband specific co-phase with equal co-phase granularity for each of the set of subbands.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the co-phase indication granularity criterion may be that, using bits of the payload, the subband co-phase granularity does not satisfy the minimum subband co-phase indication granularity, that, using the bits of the payload, the first wideband co-phase granularity at least satisfies the minimum wideband co-phase indication granularity, and that, apart from a subset of the bits of the payload used for indicating the first wideband co-phase granularity, remaining bits of the payload may be capable of subband differential co-phase indication that satisfies the minimum subband co-phase indication granularity, and where the payload interpretation rule may be that a first bit subset of the payload indicates a wideband co-phase that satisfies the minimum wideband co-phase indication granularity and that the subband co-phase granularity for each subband of a set of subbands may be differentially indicated relative to the wideband co-phase using respective bit subsets in a remainder of the payload, the subband co-phase granularity for each subband of the set of subbands having equal co-phase granularity.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the co-phase indication granularity criterion may be that, using bits of the payload, the first wideband co-phase granularity at least satisfies the minimum wideband co-phase indication granularity and that, apart from a subset of the bits of the payload used for indicating the first wideband co-phase granularity, remaining bits of the payload may be not capable of subband differential co-phase indication that satisfies the minimum subband co-phase indication granularity, and where the payload interpretation rule may be that a first bit subset of the payload indicates a wideband co-phase that satisfies the minimum wideband co-phase indication granularity.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the co-phase indication granularity criterion may be that, using bits of the payload, the first wideband co-phase granularity at least satisfies the minimum wideband co-phase indication granularity and that, apart from a subset of the bits of the payload used for indicating the first wideband co-phase granularity, remaining bits of the payload may be not capable of subband differential co-phase indication that satisfies the minimum subband co-phase indication granularity, and where the payload interpretation rule may be that bits of the payload indicate a wideband co-phase for each antenna port pair that may have a finer wideband co-phase granularity than the minimum wideband co-phase indication granularity.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the finer wideband co-phase granularity maximizes wideband co-phase granularity corresponding to the payload size.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, receiving the control signaling further may include operations, features, means, or instructions for receiving the control signaling that configures the UE with a set of different second stage uplink precoder configurations and a set of indexes respectively associated with the set of different second stage uplink precoder configurations, decoding the search space to obtain DCI and a first index of the set of indexes based on the group temporary identifier and the search offset, and selecting a first configuration from the set of different second stage uplink precoder configurations based on the DCI and the first index, where the payload of the second stage uplink precoder indication corresponds to the first configuration.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for identifying a payload size for a payload of the second stage uplink precoder indication, a fixed wideband co-phase indication granularity, a fixed subband co-phase indication granularity, and a number of subbands for frequency selective co-phase indication, determining that the payload satisfies a co-phase indication granularity criterion based on the payload size, the number of subbands, and one or both of the fixed wideband co-phase indication granularity and the fixed subband co-phase indication granularity, and applying a payload interpretation rule corresponding to the co-phase indication granularity criterion to interpret the payload of the second stage uplink precoder indication.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the identifying further may include operations, features, means, or instructions for identifying a set of parameters including one or more of the payload size for the payload of the second stage uplink precoder indication, the fixed wideband co-phase indication granularity, the fixed subband co-phase indication granularity, and the number of subbands for frequency selective co-phase indication, where the identifying may be based on at least one predefinition for one or more parameters of the set of parameters stored in a storage device of the UE, receiving an RRC configuration indicating one or more parameters of the set of parameters, receiving DCI indicating one or more parameters of the set of parameters, or any combination thereof.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the co-phase indication granularity criterion may be that, using bits of the payload, the subband co-phase granularity satisfies the fixed subband co-phase indication granularity, and where the payload interpretation rule may be that the subband co-phase granularity for each subband of a set of subbands may be indicated using a same number of bits of the payload to indicate subband specific co-phase that satisfies the fixed subband co-phase indication granularity.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the co-phase indication granularity criterion may be that, using bits of the payload, the subband co-phase granularity does not satisfy the fixed subband co-phase indication granularity, that, using the bits of the payload, the first wideband co-phase granularity satisfies the fixed wideband co-phase indication granularity, and that, apart from a subset of the bits of the payload used for indicating the first wideband co-phase granularity, remaining bits of the payload may be capable of subband differential co-phase indication that satisfies the fixed subband co-phase indication granularity, and where the payload interpretation rule may be that a first bit subset of the payload indicates a wideband co-phase that satisfies the fixed wideband co-phase indication granularity and that the subband co-phase granularity for each subband of a set of subbands may be differentially indicated relative to the wideband co-phase using respective bit subsets of the remaining bits of the payload, the subband co-phase granularity for each subband of the set of subbands satisfying the fixed subband co-phase indication granularity.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the co-phase indication granularity criterion may be that, using bits of the payload, the first wideband co-phase granularity at least satisfies the fixed wideband co-phase indication granularity and that, apart from a subset of the bits of the payload used for indicating the first wideband co-phase granularity, remaining bits of the payload may be not capable of satisfying the fixed subband co-phase indication granularity for each subband of a set of subbands, and where the payload interpretation rule may be that a first bit subset of the payload indicates a wideband co-phase that satisfies the fixed wideband co-phase indication granularity, that a second bit subset of the payload indicates a subband index bitmap, and that, for at least one subband indicated in the subband index bitmap, a third subset of the payload provides a differential subband co-phase indication relative to the wideband co-phase that satisfies the fixed subband co-phase indication granularity.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the bitmap indicates positive and negative subband indexes from the set of subbands, where a first subband subset of the set of subbands with positive indexes may be indicated with subband co-phases and a second subband subset of the set of subbands with negative indexes may be not indicated with subband co-phases.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the subband co-phase granularity for the first subband subset of the set of subbands with positive indexes satisfies the fixed subband co-phase indication granularity.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the co-phase indication granularity criterion may be that, using bits of the payload, the first wideband co-phase granularity at least satisfies the fixed wideband co-phase indication granularity and that, apart from a subset of the bits of the payload used for indicating the first wideband co-phase granularity, remaining bits of the payload may be not capable of satisfying the fixed subband co-phase indication granularity for each subband of a set of subbands, and where the payload interpretation rule may be that a first bit subset of the payload indicates a wideband co-phase that satisfies the fixed wideband co-phase indication granularity, that a second bit subset of the payload indicates a subband selection pattern, and that, for at least one subband indicated in the subband selection pattern, a third bit subset of the payload provides a differential subband co-phase indication relative to the wideband co-phase that satisfies the fixed subband co-phase indication granularity.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the second bit subset may be a combinatorial number that indicates the subband selection pattern from among a set of candidate subband selection patterns.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the subband co-phase granularity for the at least one subband indicated in the subband selection pattern indicted satisfies the fixed subband co-phase indication granularity.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the co-phase indication granularity criterion may be that, using bits of the payload, the first wideband co-phase granularity at least satisfies the fixed wideband co-phase indication granularity and that, apart from a subset of the bits of the payload used for indicating the first wideband co-phase granularity, remaining bits of the payload may be not capable of satisfying the fixed subband co-phase indication granularity for each subband of a set of subbands, and where the payload interpretation rule may be that a first bit subset of the payload indicates a wideband co-phase that satisfies the fixed wideband co-phase indication granularity, that a second bit subset of the payload indicates an adaptive subband selection rule, and that, for at least one subband of the set of subbands indicated in the adaptive subband selection rule, a third bit subset of the payload provides a differential subband co-phase indication relative to the wideband co-phase that satisfies the fixed subband co-phase indication granularity.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the adaptive subband selection rule indicates to interpret the payload as selecting, starting from a nth subband of the set of subbands, every (K+n) th, (2K+n) th, (3K+n) th subband, where K may be selected so that the third bit subset provides differential subband co-phase indication that satisfies the fixed subband co-phase indication granularity, and n may be preconfigured or RRC configured.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the second stage uplink precoder indication indicates the first wideband co-phase granularity for at least one antenna port pair of a set of antenna ports, where the transmission may be transmitted using the set of antenna ports.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the second stage uplink precoder indication indicates the subband co-phase granularity for at least one antenna port pair of a set of antenna ports, where the transmission may be transmitted using the set of antenna ports.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, transmitting the transmission may include operations, features, means, or instructions for transmitting the transmission in a physical uplink shared channel (PUSCH) .

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the transmission may be a non-configured grant transmission or a configured grant transmission.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first stage uplink precoder indication may be an uplink precoding matrix indicator (PMI) .

A method of wireless communications by a base station is described. The method may include transmitting a first stage uplink precoder indication of wideband precoding, transmitting a second stage uplink precoder indication of a first wideband co-phase granularity for the wideband precoding, a subband co-phase granularity for subband uplink precoding, or both, each of the first wideband co-phase granularity and the subband co-phase granularity being finer than a second wideband co-phase granularity indicated by the first stage uplink precoder indication, and monitoring for a signal generated based on information precoded in accordance with the first stage uplink precoder indication and the second stage uplink precoder indication.

An apparatus for wireless communications by a base station is described. The apparatus may include a processor, memory in electronic communication with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to transmit a first stage uplink precoder indication of wideband precoding, transmit a second stage uplink precoder indication of a first wideband co-phase granularity for the wideband precoding, a subband co-phase granularity for subband uplink precoding, or both, each of the first wideband co-phase granularity and the subband co-phase granularity being finer than a second wideband co-phase granularity indicated by the first stage uplink precoder indication, and monitor for a signal generated based on information precoded in accordance with the first stage uplink precoder indication and the second stage uplink precoder indication.

Another apparatus for wireless communications by a base station is described. The apparatus may include means for transmitting a first stage uplink precoder indication of wideband precoding, transmitting a second stage uplink precoder indication of a first wideband co-phase granularity for the wideband precoding, a subband co-phase granularity for subband uplink precoding, or both, each of the first wideband co-phase granularity and the subband co-phase granularity being finer than a second wideband co-phase granularity indicated by the first stage uplink precoder indication, and monitoring for a signal generated based on information precoded in accordance with the first stage uplink precoder indication and the second stage uplink precoder indication.

A non-transitory computer-readable medium storing code for wireless communications by a base station is described. The code may include instructions executable by a processor to transmit a first stage uplink precoder indication of wideband precoding, transmit a second stage uplink precoder indication of a first wideband co-phase granularity for the wideband precoding, a subband co-phase granularity for subband uplink precoding, or both, each of the first wideband co-phase granularity and the subband co-phase granularity being finer than a second wideband co-phase granularity indicated by the first stage uplink precoder indication, and monitor for a signal generated based on information precoded in accordance with the first stage uplink precoder indication and the second stage uplink precoder indication.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting control signaling that configures a UE with a resource for transmitting the signal.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting control signaling that includes the first stage uplink precoder indication and the second stage uplink precoder indication.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting DCI that includes the first stage uplink precoder indication and the second stage uplink precoder indication.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, transmitting the first stage uplink precoder indication and the second stage uplink precoder indication may include operations, features, means, or instructions for transmitting an RRC configuration that includes the first stage uplink precoder indication and DCI that includes the second stage uplink precoder indication.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting DCI that schedules the UE to transmit the signal.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the DCI includes the second stage uplink precoder indication.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the DCI includes the first stage uplink precoder indication.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting control signaling that configures a UE with a group temporary identifier and a search offset.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, transmitting the control signaling may include operations, features, means, or instructions for transmitting the control signaling that configures the UE with a set of different second stage uplink precoder configurations.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, transmitting the control signaling may include operations, features, means, or instructions for transmitting the control signaling that configures the UE with a set of different second stage uplink precoder configurations and a set of indexes respectively associated with the set of different second stage uplink precoder configurations.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first stage uplink precoder indication may be a PMI.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for identifying a payload size for a payload of the second stage uplink precoder indication, a minimum wideband co-phase indication granularity, a minimum subband co-phase indication granularity, and a number of subbands for frequency selective co-phase indication, determining that the payload satisfies a co-phase indication granularity criterion based on the payload size, the number of subbands, and one or both of the minimum wideband co-phase indication granularity and the minimum subband co-phase indication granularity, and generating the payload of the second stage uplink precoder indication in accordance with a payload interpretation rule corresponding to the co-phase indication granularity criterion.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the identifying further may include operations, features, means, or instructions for identifying a set of parameters including one or more of the payload size for the payload of the second stage uplink precoder indication, the minimum wideband co-phase indication granularity, the minimum subband co-phase indication granularity, and the number of subbands for frequency selective co-phase indication, where the identifying may be based on at least one predefinition for one or more parameters of the set of parameters, an RRC configuration indicating one or more parameters of the set of parameters, DCI indicating one or more parameters of the set of parameters, or any combination thereof.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for identifying a payload size for a payload of the second stage uplink precoder indication, a fixed wideband co-phase indication granularity, a fixed subband co-phase indication granularity, and a number of subbands for frequency selective co-phase indication, determining that the payload satisfies a co-phase indication granularity criterion based on the payload size, the number of subbands, and one or both of the fixed wideband co-phase indication granularity and the fixed subband co-phase indication granularity, and generating the payload of the second stage uplink precoder indication in accordance with a payload interpretation rule corresponding to the co-phase indication granularity criterion.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the identifying further may include operations, features, means, or instructions for identifying a set of parameters including one or more of the payload size for the payload of the second stage uplink precoder indication, the fixed wideband co-phase indication granularity, the fixed subband co-phase indication granularity, and the number of subbands for frequency selective co-phase indication, where the identifying may be based on at least one predefinition for one or more parameters of the set of parameters, an RRC configuration indicating one or more parameters of the set of parameters, DCI indicating one or more parameters of the set of parameters, or any combination thereof.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the co-phase indication granularity criterion may be that, using bits of the payload, the subband co-phase granularity satisfies the fixed subband co- phase indication granularity, and where the payload interpretation rule may be that the subband co-phase granularity for each subband of a set of subbands may be indicated using a same number of bits of the payload to indicate subband specific co-phase that satisfies the fixed subband co-phase indication granularity.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the subband index bitmap indicates positive and negative subband indexes from the set of subbands, where a first subband subset of the set of subbands with positive indexes may be indicated with subband co-phases and a second subband subset of the set of subbands with negative indexes may be not indicated with subband co-phases.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, receiving the control signaling further may include operations, features, means, or instructions for transmitting the control signaling that configures the UE with a set of different second stage uplink precoder configurations and a set of indexes respectively associated with the set of different second stage uplink precoder configurations.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the second stage uplink precoder indication indicates the wideband co-phase granularity for at least one antenna port pair of a set of antenna ports.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the second stage uplink precoder indication indicates the subband co-phase granularity for at least one antenna port pair of a set of antenna ports.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving the signal in a PUSCH.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the signal may be a non-configured grant transmission or a configured grant transmission.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first stage uplink precoder indication may be an uplink PMI.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. FIG. 1 illustrates an example of a system for wireless communications that supports frequency selective uplink precoder indication in accordance with aspects of the present disclosure.

FIG. 2 illustrates an example of a wireless communications system that supports frequency selective uplink precoder indication in accordance with aspects of the present disclosure.

FIG. 3 illustrates an example of a group common downlink control information (GC-DCI) configuration that supports frequency selective uplink precoder indication in accordance with aspects of the present disclosure.

FIGs. 4 and 5 illustrate examples of uplink precoder indication configurations that support frequency selective uplink precoder indication in accordance with aspects of the present disclosure.

FIG. 6 illustrates an example of a process flow that supports frequency selective uplink precoder indication in accordance with aspects of the present disclosure.

FIGs. 7 and 8 show block diagrams of devices that support frequency selective uplink precoder indication in accordance with aspects of the present disclosure.

FIG. 9 shows a block diagram of a communications manager that supports frequency selective uplink precoder indication in accordance with aspects of the present disclosure.

FIG. 10 shows a diagram of a system including a device that supports frequency selective uplink precoder indication in accordance with aspects of the present disclosure.

FIGs. 11 and 12 show block diagrams of devices that support frequency selective uplink precoder indication in accordance with aspects of the present disclosure.

FIG. 13 shows a block diagram of a communications manager that supports frequency selective uplink precoder indication in accordance with aspects of the present disclosure.

FIG. 14 shows a diagram of a system including a device that supports frequency selective uplink precoder indication in accordance with aspects of the present disclosure.

FIGs. 15 through 23 show flowcharts illustrating methods that support frequency selective uplink precoder indication in accordance with aspects of the present disclosure.

DETAILED DESCRIPTION

A base station and a user equipment (UE) in a wireless communications system may communicate using beamformed communications. In some cases, the UE may apply an uplink precoder to precode uplink information to enhance uplink beamformed transmissions. By applying the uplink precoder, a transmission direction, phase, or both, may be adjusted to provide improved signal quality and strength. The UE may have a codebook of uplink precoders for precoding uplink transmissions, such as a precoding matrix indicator (PMI) codebook. The base station may indicate which uplink precoder of the codebook the UE is to use for an uplink transmission. The base station may transmit a first stage uplink precoder indication to the UE, which may map to a precoder included in the PMI codebook. Generally, the precoders in the codebook may relate to wideband transmissions, and the precoders may not have a very fine co-phase granularity (e.g., a granularity of π/2 or less) . In some cases, the UE and base station may be configured to support frequency-selective uplink precoding and finer uplink precoder inter-port co-phase granularity than the precoders in the PMI codebook. However, modifying a conventional codebook to support frequency-selective precoders and finer uplink precoder inter-port co-phase granularity may greatly increase the size of the codebook, which may increase overhead when indicating precoders, as well as increase complexity for other wireless devices in the wireless communications system.

Wireless devices described herein, such as UEs and base stations, may implement techniques to support a two-stage uplink precoder indication, which may enable frequency-selective uplink precoding and finer granularity uplink precoders. For the first stage, the base station may transmit a first stage uplink precoder indication, and the UE may identify an uplink precoder (e.g., a first stage, wideband uplink precoder) from the PMI codebook. The base station may also transmit a second stage uplink precoder indication. The second stage uplink precoder indication may indicate an uplink precoder that has a finer inter-port co-phase granularity than indicated by the first stage uplink precoder indication. The uplink precoders indicated by the second stage uplink precoder indication may be for wideband precoding, or be for subband-specific precoding (e.g., to support frequency-selective precoding) , or both. In some cases, the second stage uplink precoder indication may be transmitted in downlink control information (DCI) .

In some examples, the base station may configure the UE with different configurations or choices for second stage uplink precoder information via Radio Resource Control (RRC) signaling, and may transmit an indicator of the selected second stage uplink precoder information dynamically via DCI. In some cases, the second stage uplink precoder indication may be carried in the same DCI as the first stage uplink precoder indication, or the second stage uplink precoder indication may be conveyed in a separate DCI which may be associated with the DCI carrying the first stage uplink precoder indication.

In some cases, the second stage uplink precoder indication may be transmitted in a group common DCI (GC-DCI) . A payload for the second stage uplink precoder indication may not be large, for example if the number of subbands is small, or the co-phase granularity is not very fine. Therefore, to reduce the overhead of attaching a cyclic redundancy check (CRC) for a small payload of a UE-specific DCI, the base station may transmit a GC-DCI to indicate the second stage uplink precoder. The UE may be configured with a group common radio network temporary identifier (GC-RNTI) and a GC-DCI offset by the base station. The UE may receive the GC-DCI, attempt to decode the GC-DCI using the GC-RNTI, and search for information specific to the UE in the GC-DCI based on the offset. In some cases, the UE may be RRC-configured with multiple different second stage uplink precoder configurations, and the base station may transmit the GC-DCI to dynamically indicate a selected second stage uplink precoder configuration. This may further reduce overhead for DCI signaling and improve signaling efficiency for the UE and base station, as most overhead-intensive signaling may be performed semi-statically via RRC.

In some cases, the techniques described herein may support that the overhead of the uplink precoder indication is a fixed number of bits. In some cases, using a fixed payload size may be advantageous for transmitting the second stage uplink precoder indication in DCI. However, if the number of subbands is large, it may not be possible to indicate all subband uplink precoders with sufficiently fine granularity while using a small fixed number of bits. Therefore, either co-phase granularity or the number of subbands may be adjusted (e.g., compromised) to fit in the fixed indication overhead. In some implementations, the base station may flexibly alter the co-phase granularity to accommodate a large number of subbands (e.g., all of the configured subbands) . In some implementations, the base station may alter the number of subbands which are included in the second stage uplink precoder indication to indicate a fine granularity for the subbands which are included. For example, selected subbands may be indicated with frequency-selected precoders, and remaining subbands may not be indicated.

The base station may generate a payload for the second stage uplink precoder indication based on a set of parameters. For example, the base station may configure the payload according to one of multiple different cases based on whether the payload fits the criterion for one of the cases. The different cases may correspond to different levels of specificity and granularity for wideband and subband-specific uplink co-phase indication. If, for example, the payload does not support a first case with high, subband-specific granularity, the payload may instead be generated based on a second case with slightly less fine granularity or which indicates co-phases for fewer subbands.

The UE may determine how the payload is configured based on the set of parameters and a set of criteria which correspond to different cases and configurations. The UE may determine which criterion of a set of co-phase indication granularity criteria the payload satisfies, and the UE may apply a corresponding interpretation rule to interpret the payload. In some cases, the UE may apply, sequentially or in parallel, respective co-phase indication granularity criterion for the different cases to determine which of the cases apply and which interpretation rule the UE should use to process the payload. The UE may then process the payload based on the interpretation rule and identify a second stage uplink precoder indication. The UE may precode uplink information in accordance with the second stage uplink precoder indication and transmit the precoded uplink information to the base station.

Particular aspects of the subject matter described herein may be implemented to realize one or more advantages. The described techniques may support improvements in uplink precoding by increasing flexibility, mitigating overhead, and increasing co-phase granularity, among other advantages. As such, supported techniques may include improved network operations and, in some examples, may promote network efficiencies, among other benefits.

Aspects of the disclosure are initially described in the context of a wireless communications system. Aspects are then described with reference to a GC-DCI configuration, uplink precoder configurations, and a process flow. Aspects of the disclosure are further illustrated by and described with reference to apparatus diagrams, system diagrams, and flowcharts that relate to frequency selective uplink precoder indication.

FIG. 1 illustrates an example of a wireless communications system 100 that supports frequency selective uplink precoder indication in accordance with aspects of the present disclosure. The wireless communications system 100 includes base stations 105, UEs 115, and a core network 130. In some examples, the wireless communications system 100 may be a Long Term Evolution (LTE) network, an LTE-Advanced (LTE-A) network, an LTE-A Pro network, or a New Radio (NR) network. In some cases, wireless communications system 100 may support enhanced broadband communications, ultra-reliable (e.g., mission critical) communications, low latency communications, or communications with low-cost and low-complexity devices.

Base stations 105 may wirelessly communicate with UEs 115 via one or more base station antennas. Base stations 105 described herein may include or may be referred to by those skilled in the art as a base transceiver station, a radio base station, an access point, a radio transceiver, a NodeB, an eNodeB (eNB) , a next-generation NodeB or giga-NodeB (either of which may be referred to as a gNB) , a Home NodeB, a Home eNodeB, or some other suitable terminology. Wireless communications system 100 may include base stations 105 of different types (e.g., macro or small cell base stations) . The UEs 115 described herein may be able to communicate with various types of base stations 105 and network equipment including macro eNBs, small cell eNBs, gNBs, relay base stations, and the like.

Each base station 105 may be associated with a particular geographic coverage area 110 in which communications with various UEs 115 is supported. Each base station 105 may provide communication coverage for a respective geographic coverage area 110 via communication links 125, and communication links 125 between a base station 105 and a UE 115 may utilize one or more carriers. Communication links 125 shown in wireless communications system 100 may include uplink transmissions from a UE 115 to a base station 105, or downlink transmissions from a base station 105 to a UE 115. Downlink transmissions may also be called forward link transmissions while uplink transmissions may also be called reverse link transmissions.

The geographic coverage area 110 for a base station 105 may be divided into sectors making up a portion of the geographic coverage area 110, and each sector may be associated with a cell. For example, each base station 105 may provide communication coverage for a macro cell, a small cell, a hot spot, or other types of cells, or various combinations thereof. In some examples, a base station 105 may be movable and therefore provide communication coverage for a moving geographic coverage area 110. In some examples, different geographic coverage areas 110 associated with different technologies may overlap, and overlapping geographic coverage areas 110 associated with different technologies may be supported by the same base station 105 or by different base stations 105. The wireless communications system 100 may include, for example, a heterogeneous LTE/LTE-A/LTE-A Pro or NR network in which different types of base stations 105 provide coverage for various geographic coverage areas 110.

The term “cell” refers to a logical communication entity used for communication with a base station 105 (e.g., over a carrier) , and may be associated with an identifier for distinguishing neighboring cells (e.g., a physical cell identifier (PCID) , a virtual cell identifier (VCID) ) operating via the same or a different carrier. In some examples, a carrier may support multiple cells, and different cells may be configured according to different protocol types (e.g., machine-type communication (MTC) , narrowband Internet-of-Things (NB-IoT) , enhanced mobile broadband (eMBB) , or others) that may provide access for different types of devices. In some cases, the term “cell” may refer to a portion of a geographic coverage area 110 (e.g., a sector) over which the logical entity operates.

UEs 115 may be dispersed throughout the wireless communications system 100, and each UE 115 may be stationary or mobile. A UE 115 may also be referred to as a mobile device, a wireless device, a remote device, a handheld device, or a subscriber device, or some other suitable terminology, where the “device” may also be referred to as a unit, a station, a terminal, or a client. A UE 115 may also be a personal electronic device such as a cellular phone, a personal digital assistant (PDA) , a tablet computer, a laptop computer, or a personal computer. In some examples, a UE 115 may also refer to a wireless local loop (WLL) station, an Internet of Things (IoT) device, an Internet of Everything (IoE) device, or an MTC device, or the like, which may be implemented in various articles such as appliances, vehicles, meters, or the like.

Some UEs 115, such as MTC or IoT devices, may be low cost or low complexity devices, and may provide for automated communication between machines (e.g., via Machine-to-Machine (M2M) communication) . M2M communication or MTC may refer to data communication technologies that allow devices to communicate with one another or a base station 105 without human intervention. In some examples, M2M communication or MTC may include communications from devices that integrate sensors or meters to measure or capture information and relay that information to a central server or application program that can make use of the information or present the information to humans interacting with the program or application. Some UEs 115 may be designed to collect information or enable automated behavior of machines. Examples of applications for MTC devices include smart metering, inventory monitoring, water level monitoring, equipment monitoring, healthcare monitoring, wildlife monitoring, weather and geological event monitoring, fleet management and tracking, remote security sensing, physical access control, and transaction-based business charging.

Some UEs 115 may be configured to employ operating modes that reduce power consumption, such as half-duplex communications (e.g., a mode that supports one-way communication via transmission or reception, but not transmission and reception simultaneously) . In some examples, half-duplex communications may be performed at a reduced peak rate. Other power conservation techniques for UEs 115 include entering a power saving “deep sleep” mode when not engaging in active communications, or operating over a limited bandwidth (e.g., according to narrowband communications) . In some cases, UEs 115 may be designed to support critical functions (e.g., mission critical functions) , and a wireless communications system 100 may be configured to provide ultra-reliable communications for these functions.

In some cases, a UE 115 may also be able to communicate directly with other UEs 115 (e.g., using a peer-to-peer (P2P) or device-to-device (D2D) protocol) . One or more of a group of UEs 115 utilizing D2D communications may be within the geographic coverage area 110 of a base station 105. Other UEs 115 in such a group may be outside the geographic coverage area 110 of a base station 105, or be otherwise unable to receive transmissions from a base station 105. In some cases, groups of UEs 115 communicating via D2D communications may utilize a one-to-many (1: M) system in which each UE 115 transmits to every other UE 115 in the group. In some cases, a base station 105 facilitates the scheduling of resources for D2D communications. In other cases, D2D communications are carried out between UEs 115 without the involvement of a base station 105.

Base stations 105 may communicate with the core network 130 and with one another. For example, base stations 105 may interface with the core network 130 through backhaul links 132 (e.g., via an S1, N2, N3, or other interface) . Base stations 105 may communicate with one another over backhaul links 134 (e.g., via an X2, Xn, or other interface) either directly (e.g., directly between base stations 105) or indirectly (e.g., via core network 130) .

The core network 130 may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. The core network 130 may be an evolved packet core (EPC) , which may include at least one mobility management entity (MME) , at least one serving gateway (S-GW) , and at least one Packet Data Network (PDN) gateway (P-GW) . The MME may manage non-access stratum (e.g., control plane) functions such as mobility, authentication, and bearer management for UEs 115 served by base stations 105 associated with the EPC. User IP packets may be transferred through the S-GW, which itself may be connected to the P-GW. The P-GW may provide IP address allocation as well as other functions. The P-GW may be connected to the network operators IP services. The operators IP services may include access to the Internet, Intranet (s) , an IP Multimedia Subsystem (IMS) , or a Packet-Switched (PS) Streaming Service.

At least some of the network devices, such as a base station 105, may include subcomponents such as an access network entity, which may be an example of an access node controller (ANC) . Each access network entity may communicate with UEs 115 through a number of other access network transmission entities, which may be referred to as a radio head, a smart radio head, or a transmission/reception point (TRP) . In some configurations, various functions of each access network entity or base station 105 may be distributed across various network devices (e.g., radio heads and access network controllers) or consolidated into a single network device (e.g., a base station 105) .

Wireless communications system 100 may operate using one or more frequency bands, typically in the range of 300 megahertz (MHz) to 300 gigahertz (GHz) . Generally, the region from 300 MHz to 3 GHz is known as the ultra-high frequency (UHF) region or decimeter band, since the wavelengths range from approximately one decimeter to one meter in length. UHF waves may be blocked or redirected by buildings and environmental features. However, the waves may penetrate structures sufficiently for a macro cell to provide service to UEs 115 located indoors. Transmission of UHF waves may be associated with smaller antennas and shorter range (e.g., less than 100 km) compared to transmission using the smaller frequencies and longer waves of the high frequency (HF) or very high frequency (VHF) portion of the spectrum below 300 MHz.

Wireless communications system 100 may also operate in a super high frequency (SHF) region using frequency bands from 3 GHz to 30 GHz, also known as the centimeter band. The SHF region includes bands such as the 5 GHz industrial, scientific, and medical (ISM) bands, which may be used opportunistically by devices that may be capable of tolerating interference from other users.

Wireless communications system 100 may also operate in an extremely high frequency (EHF) region of the spectrum (e.g., from 30 GHz to 300 GHz) , also known as the millimeter band. In some examples, wireless communications system 100 may support millimeter wave (mmW) communications between UEs 115 and base stations 105, and EHF antennas of the respective devices may be even smaller and more closely spaced than UHF antennas. In some cases, this may facilitate use of antenna arrays within a UE 115. However, the propagation of EHF transmissions may be subject to even greater atmospheric attenuation and shorter range than SHF or UHF transmissions. Techniques disclosed herein may be employed across transmissions that use one or more different frequency regions, and designated use of bands across these frequency regions may differ by country or regulating body.

In some cases, wireless communications system 100 may utilize both licensed and unlicensed radio frequency spectrum bands. For example, wireless communications system 100 may employ License Assisted Access (LAA) , LTE-Unlicensed (LTE-U) radio access technology, or NR technology in an unlicensed band such as the 5 GHz ISM band. When operating in unlicensed radio frequency spectrum bands, wireless devices such as base stations 105 and UEs 115 may employ listen-before-talk (LBT) procedures to ensure a frequency channel is clear before transmitting data. In some cases, operations in unlicensed bands may be based on a carrier aggregation configuration in conjunction with component carriers operating in a licensed band (e.g., LAA) . Operations in unlicensed spectrum may include downlink transmissions, uplink transmissions, peer-to-peer transmissions, or a combination of these. Duplexing in unlicensed spectrum may be based on frequency division duplexing (FDD) , time division duplexing (TDD) , or a combination of both.

In some examples, base station 105 or UE 115 may be equipped with multiple antennas, which may be used to employ techniques such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communications, or beamforming. For example, wireless communications system 100 may use a transmission scheme between a transmitting device (e.g., a base station 105) and a receiving device (e.g., a UE 115) , where the transmitting device is equipped with multiple antennas and the receiving device is equipped with one or more antennas. MIMO communications may employ multipath signal propagation to increase the spectral efficiency by transmitting or receiving multiple signals via different spatial layers, which may be referred to as spatial multiplexing. The multiple signals may, for example, be transmitted by the transmitting device via different antennas or different combinations of antennas. Likewise, the multiple signals may be received by the receiving device via different antennas or different combinations of antennas. Each of the multiple signals may be referred to as a separate spatial stream, and may carry bits associated with the same data stream (e.g., the same codeword) or different data streams. Different spatial layers may be associated with different antenna ports used for channel measurement and reporting. MIMO techniques include single-user MIMO (SU-MIMO) where multiple spatial layers are transmitted to the same receiving device, and multiple-user MIMO (MU-MIMO) where multiple spatial layers are transmitted to multiple devices.

Beamforming, which may also be referred to as spatial filtering, directional transmission, or directional reception, is a signal processing technique that may be used at a transmitting device or a receiving device (e.g., a base station 105 or a UE 115) to shape or steer an antenna beam (e.g., a transmit beam or receive beam) along a spatial path between the transmitting device and the receiving device. Beamforming may be achieved by combining the signals communicated via antenna elements of an antenna array such that signals propagating at particular orientations with respect to an antenna array experience constructive interference while others experience destructive interference. The adjustment of signals communicated via the antenna elements may include a transmitting device or a receiving device applying certain amplitude and phase offsets to signals carried via each of the antenna elements associated with the device. The adjustments associated with each of the antenna elements may be defined by a beamforming weight set associated with a particular orientation (e.g., with respect to the antenna array of the transmitting device or receiving device, or with respect to some other orientation) .

In one example, a base station 105 may use multiple antennas or antenna arrays to conduct beamforming operations for directional communications with a UE 115. For instance, some signals (e.g., synchronization signals, reference signals, beam selection signals, or other control signals) may be transmitted by a base station 105 multiple times in different directions, which may include a signal being transmitted according to different beamforming weight sets associated with different directions of transmission. Transmissions in different beam directions may be used to identify (e.g., by the base station 105 or a receiving device, such as a UE 115) a beam direction for subsequent transmission and/or reception by the base station 105.

Some signals, such as data signals associated with a particular receiving device, may be transmitted by a base station 105 in a single beam direction (e.g., a direction associated with the receiving device, such as a UE 115) . In some examples, the beam direction associated with transmissions along a single beam direction may be determined based at least in in part on a signal that was transmitted in different beam directions. For example, a UE 115 may receive one or more of the signals transmitted by the base station 105 in different directions, and the UE 115 may report to the base station 105 an indication of the signal the UE 115 received with a highest signal quality, or an otherwise acceptable signal quality. Although these techniques are described with reference to signals transmitted in one or more directions by a base station 105, a UE 115 may employ similar techniques for transmitting signals multiple times in different directions (e.g., for identifying a beam direction for subsequent transmission or reception by the UE 115) , or transmitting a signal in a single direction (e.g., for transmitting data to a receiving device) .

A receiving device (e.g., a UE 115, which may be an example of a mmW receiving device) may try multiple receive beams when receiving various signals from the base station 105, such as synchronization signals, reference signals, beam selection signals, or other control signals. For example, a receiving device may try multiple receive directions by receiving via different antenna subarrays, by processing received signals according to different antenna subarrays, by receiving according to different receive beamforming weight sets applied to signals received at a set of antenna elements of an antenna array, or by processing received signals according to different receive beamforming weight sets applied to signals received at a set of antenna elements of an antenna array, any of which may be referred to as “listening” according to different receive beams or receive directions. In some examples, a receiving device may use a single receive beam to receive along a single beam direction (e.g., when receiving a data signal) . The single receive beam may be aligned in a beam direction determined based on listening according to different receive beam directions (e.g., a beam direction determined to have a highest signal strength, highest signal-to-noise ratio, or otherwise acceptable signal quality based on listening according to multiple beam directions) .

In some cases, the antennas of a base station 105 or UE 115 may be located within one or more antenna arrays, which may support MIMO operations, or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays may be co-located at an antenna assembly, such as an antenna tower. In some cases, antennas or antenna arrays associated with a base station 105 may be located in diverse geographic locations. A base station 105 may have an antenna array with a number of rows and columns of antenna ports that the base station 105 may use to support beamforming of communications with a UE 115. Likewise, a UE 115 may have one or more antenna arrays that may support various MIMO or beamforming operations.

In some cases, wireless communications system 100 may be a packet-based network that operate according to a layered protocol stack. In the user plane, communications at the bearer or Packet Data Convergence Protocol (PDCP) layer may be IP-based. A Radio Link Control (RLC) layer may perform packet segmentation and reassembly to communicate over logical channels. A Medium Access Control (MAC) layer may perform priority handling and multiplexing of logical channels into transport channels. The MAC layer may also use hybrid automatic repeat request (HARQ) to provide retransmission at the MAC layer to improve link efficiency. In the control plane, the RRC protocol layer may provide establishment, configuration, and maintenance of an RRC connection between a UE 115 and a base station 105 or core network 130 supporting radio bearers for user plane data. At the Physical layer, transport channels may be mapped to physical channels.

In some cases, UEs 115 and base stations 105 may support retransmissions of data to increase the likelihood that data is received successfully. HARQ feedback is one technique of increasing the likelihood that data is received correctly over a communication link 125. HARQ may include a combination of error detection (e.g., using a CRC) , forward error correction (FEC) , and retransmission (e.g., automatic repeat request (ARQ) ) . HARQ may improve throughput at the MAC layer in poor radio conditions (e.g., signal-to-noise conditions) . In some cases, a wireless device may support same-slot HARQ feedback, where the device may provide HARQ feedback in a specific slot for data received in a previous symbol in the slot. In other cases, the device may provide HARQ feedback in a subsequent slot, or according to some other time interval.

Time intervals in LTE or NR may be expressed in multiples of a basic time unit, which may, for example, refer to a sampling period of T _s = 1/30,720,000 seconds. Time intervals of a communications resource may be organized according to radio frames each having a duration of 10 milliseconds (ms) , where the frame period may be expressed as T _f = 307, 200 T _s. The radio frames may be identified by a system frame number (SFN) ranging from 0 to 1023. Each frame may include 10 subframes numbered from 0 to 9, and each subframe may have a duration of 1 ms. A subframe may be further divided into 2 slots each having a duration of 0.5 ms, and each slot may contain 6 or 7 modulation symbol periods (e.g., depending on the length of the cyclic prefix prepended to each symbol period) . Excluding the cyclic prefix, each symbol period may contain 2048 sampling periods. In some cases, a subframe may be the smallest scheduling unit of the wireless communications system 100, and may be referred to as a transmission time interval (TTI) . In other cases, a smallest scheduling unit of the wireless communications system 100 may be shorter than a subframe or may be dynamically selected (e.g., in bursts of shortened TTIs (sTTIs) or in selected component carriers using sTTIs) .

In some wireless communications systems, a slot may further be divided into multiple mini-slots containing one or more symbols. In some instances, a symbol of a mini-slot or a mini-slot may be the smallest unit of scheduling. Each symbol may vary in duration depending on the subcarrier spacing or frequency band of operation, for example. Further, some wireless communications systems may implement slot aggregation in which multiple slots or mini-slots are aggregated together and used for communication between a UE 115 and a base station 105.

The term “carrier” refers to a set of radio frequency spectrum resources having a defined physical layer structure for supporting communications over a communication link 125. For example, a carrier of a communication link 125 may include a portion of a radio frequency spectrum band that is operated according to physical layer channels for a given radio access technology. Each physical layer channel may carry user data, control information, or other signaling. A carrier may be associated with a pre-defined frequency channel (e.g., an evolved universal mobile telecommunication system terrestrial radio access (E-UTRA) absolute radio frequency channel number (EARFCN) ) , and may be positioned according to a channel raster for discovery by UEs 115. Carriers may be downlink or uplink (e.g., in an FDD mode) , or be configured to carry downlink and uplink communications (e.g., in a TDD mode) . In some examples, signal waveforms transmitted over a carrier may be made up of multiple sub-carriers (e.g., using multi-carrier modulation (MCM) techniques such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform spread OFDM (DFT-S-OFDM) ) .

The organizational structure of the carriers may be different for different radio access technologies (e.g., LTE, LTE-A, LTE-A Pro, NR) . For example, communications over a carrier may be organized according to TTIs or slots, each of which may include user data as well as control information or signaling to support decoding the user data. A carrier may also include dedicated acquisition signaling (e.g., synchronization signals or system information) and control signaling that coordinates operation for the carrier. In some examples (e.g., in a carrier aggregation configuration) , a carrier may also have acquisition signaling or control signaling that coordinates operations for other carriers.

Physical channels may be multiplexed on a carrier according to various techniques. A physical control channel and a physical data channel may be multiplexed on a downlink carrier, for example, using time division multiplexing (TDM) techniques, frequency division multiplexing (FDM) techniques, or hybrid TDM-FDM techniques. In some examples, control information transmitted in a physical control channel may be distributed between different control regions in a cascaded manner (e.g., between a common control region or common search space and one or more UE-specific control regions or UE-specific search spaces) .

A carrier may be associated with a particular bandwidth of the radio frequency spectrum, and in some examples the carrier bandwidth may be referred to as a “system bandwidth” of the carrier or the wireless communications system 100. For example, the carrier bandwidth may be one of a number of predetermined bandwidths for carriers of a particular radio access technology (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 MHz) . In some examples, each served UE 115 may be configured for operating over portions or all of the carrier bandwidth. In other examples, some UEs 115 may be configured for operation using a narrowband protocol type that is associated with a predefined portion or range (e.g., set of subcarriers or RBs) within a carrier (e.g., “in-band” deployment of a narrowband protocol type) .

In a system employing MCM techniques, a resource element may consist of one symbol period (e.g., a duration of one modulation symbol) and one subcarrier, where the symbol period and subcarrier spacing are inversely related. The number of bits carried by each resource element may depend on the modulation scheme (e.g., the order of the modulation scheme) . Thus, the more resource elements that a UE 115 receives and the higher the order of the modulation scheme, the higher the data rate may be for the UE 115. In MIMO systems, a wireless communications resource may refer to a combination of a radio frequency spectrum resource, a time resource, and a spatial resource (e.g., spatial layers) , and the use of multiple spatial layers may further increase the data rate for communications with a UE 115.

Devices of the wireless communications system 100 (e.g., base stations 105 or UEs 115) may have a hardware configuration that supports communications over a particular carrier bandwidth, or may be configurable to support communications over one of a set of carrier bandwidths. In some examples, the wireless communications system 100 may include base stations 105 and/or UEs 115 that support simultaneous communications via carriers associated with more than one different carrier bandwidth.

Wireless communications system 100 may support communication with a UE 115 on multiple cells or carriers, a feature which may be referred to as carrier aggregation or multi-carrier operation. A UE 115 may be configured with multiple downlink component carriers and one or more uplink component carriers according to a carrier aggregation configuration. Carrier aggregation may be used with both FDD and TDD component carriers.

In some cases, wireless communications system 100 may utilize enhanced component carriers (eCCs) . An eCC may be characterized by one or more features including wider carrier or frequency channel bandwidth, shorter symbol duration, shorter TTI duration, or modified control channel configuration. In some cases, an eCC may be associated with a carrier aggregation configuration or a dual connectivity configuration (e.g., when multiple serving cells have a suboptimal or non-ideal backhaul link) . An eCC may also be configured for use in unlicensed spectrum or shared spectrum (e.g., where more than one operator is allowed to use the spectrum) . An eCC characterized by wide carrier bandwidth may include one or more segments that may be utilized by UEs 115 that are not capable of monitoring the whole carrier bandwidth or are otherwise configured to use a limited carrier bandwidth (e.g., to conserve power) .

In some cases, an eCC may utilize a different symbol duration than other component carriers, which may include use of a reduced symbol duration as compared with symbol durations of the other component carriers. A shorter symbol duration may be associated with increased spacing between adjacent subcarriers. A device, such as a UE 115 or base station 105, utilizing eCCs may transmit wideband signals (e.g., according to frequency channel or carrier bandwidths of 20, 40, 60, 80 MHz) at reduced symbol durations (e.g., 16.67 microseconds) . A TTI in eCC may consist of one or multiple symbol periods. In some cases, the TTI duration (that is, the number of symbol periods in a TTI) may be variable.

A UE 115 and a base station 105 may support configured-grant transmission schemes, non-configured-grant transmission schemes, or both. For non-configured-grant transmission schemes, a base station 105 may transmit a grant to a UE 115 which indicates a set of resources. The UE 115 may then communicate (e.g., either transmit to the base station 105 or monitor for a downlink transmission from the base station 105) on those resources as indicated by the grant. The grant may be transmitted in DCI, and resources allocated to the UE 115 may be dynamically allocated.

For configured-grant transmission schemes, the UE 115 may instead be pre-configured with a set of resources. In some cases, the set of resources for configured-grant transmission schemes may be configured over RRC or other higher layer signaling. The base station 105 may then transmit an indicator to the UE 115 to activate communications for the UE 115 on the set of resources. For example, the base station 105 may transmit an indicator to the UE 115 which activates communications on at least a portion of the set of resources, and the UE 115 may then communicate (e.g., transmit to the base station 105 or monitor for a downlink transmission from the base station 105) on the portion of the set of resources based on receiving the indicator. In some cases, configured-grant transmission schemes may be less dynamic than non-configured-grant transmission schemes, but overhead for DCI signaling may be decreased.

Wireless communications system 100 may be an NR system that may utilize any combination of licensed, shared, and unlicensed spectrum bands, among others. The flexibility of eCC symbol duration and subcarrier spacing may allow for the use of eCC across multiple spectrums. In some examples, NR shared spectrum may increase spectrum utilization and spectral efficiency, specifically through dynamic vertical (e.g., across the frequency domain) and horizontal (e.g., across the time domain) sharing of resources.

A UE 115 and a base station 105 may support techniques for a two stage uplink precoder indication. The base station 105 may transmit a first stage uplink precoder indication and a second stage uplink precoder indication, where the second stage uplink precoder indication may support frequency-selective uplink precoder indication, higher granularity precoder indication, or both. Different types of signaling for the second stage uplink precoder indication are described, including at least transmitting the second stage uplink precoder indication via GC-DCI. In some cases, the GC-DCI transmission may be used in addition to, or as an alternative to, RRC signaling. For example, the base station 105 may configure multiple second stage uplink precoder configurations via RRC, then the base station 105 may indicate, over DCI such as GC-DCI, which of the multiple second stage uplink precoder configurations the UE 115 is to apply.

Additionally, techniques for generating (e.g., at a base station 105) and interpreting (e.g., at a UE 115) a payload for the second stage uplink precoder indication are described. A payload for the second stage uplink precoder indication may be configured based on which co-phase indication granularity criterion of a set of different co-phase indication granularity criteria the payload satisfies. Each of the different co-phase indication granularity criteria may correspond to a different case of co-phase indication granularity. The base station 105 may generate the payload according to one of the different cases based on how granular the co-phase indication can be given the payload size and other parameters. The UE 115 may then determine which co-phase indication granularity criterion the payload satisfies and apply a corresponding payload interpretation rule to interpret the payload.

FIG. 2 illustrates an example of a wireless communications system 200 that supports frequency selective uplink precoder indication in accordance with aspects of the present disclosure. In some examples, the wireless communications system 200 may implement aspects of wireless communication system 100. The wireless communications system 200 may include base station 105-a and UE 115-a, which may be respective examples of a base station 105 and a UE 115 as described with reference to FIG. 1. In some cases, UE 115-a and base station 105-a may be examples of wireless devices which implement techniques to support a two stage uplink precoder indication.

The wireless communications system 200 may support beamformed communications. For example, base station 105-a may directionally transmit to UE 115-a, and UE 115-a may directionally transmit to base station 105-a. In some cases, UE 115-a may apply an uplink precoder to precode uplink information to enhance uplink beamformed transmissions. In some cases, a transmission direction, phase, or both, may be modified based on an uplink precoder applied to the uplink information. An uplink precoder may specify a co-phase for a pair of antenna ports from an antenna array 235 or multiple antenna arrays or multiple antenna elements, or any combination thereof. UE 115-a may have multiple (e.g., N) antenna elements in the one or more antenna arrays or antenna elements. In some cases, UE 115-a may support the co-phase indication between the antenna-port-pairs of the (1, 2) , (1, 2) , ..., (1, N) from the overall N antenna ports, where all of the antenna ports may be capable of jointly coherent transmission. In some cases, UE 115-a may be equipped with several separated antenna elements, where each element may be an array or a single element. A co-phase may refer to a phase relationship between a first antenna port of the antenna array 235 and a second antenna port of the antenna array 235. In some cases, the co-phase may assist UE 115-a in spatial multiplexing for beamformed communications.

UE 115-a may have a codebook 230 of uplink precoders for precoding uplink transmissions. Some codebooks of some wireless systems may support up to 4-port uplink precoders. In some cases, these codebooks may have an inter-port co-phase granularity up to

In some cases, the codebook 230 of UE 115-a may also support up to 4-port uplink precoders with an inter-port co-phase granularity up to

Or, in some cases, the codebook 230 of UE 115-a may support a different number of uplink precoder ports or a different co-phase granularity, or both. In some cases, the codebook 230 may be an example of a PMI codebook, or a transmitted PMI (TPMI) codebook.

In some cases, base station 105-a may indicate which uplink precoder UE 115-a is to use for precoding an uplink transmission. Base station 105-a may transmit a first precoder indication 215 to UE 115-a. The first precoder indication 215 may include precoders identifiable in the codebook 230 and may indicate a wideband uplink precoder with a relatively large inter-port co-phase granularity (e.g.,

) . For example, the first precoder indication 215 may correspond (e.g., via an index) to an uplink precoder in the codebook 230, and UE 115-a may apply the corresponding uplink precoder to uplink information for the uplink transmission 225. In some cases, the first precoder indication 215 may be transmitted in DCI scheduling a physical uplink shared channel (PUSCH) for non-configured-grant transmissions. For configured-grant transmissions (e.g., in Type-1 configured grant transmissions) , the first precoder indication 215 may be configured via RRC signaling (e.g., during RRC configuration that configures the uplink grant) . In Type-2 configured grant transmissions, the first precoder indication 215 may be transmitted in DCI activating a configured-grant PUSCH transmission. In some examples, the first precoder indication 215 may indicate a wideband precoder, and not subband precoders.

In some cases, UE 115-a and base station 105-a may support frequency-selective uplink precoding, finer uplink precoder inter-port co-phase granularity than the precoders in a conventional codebook, or both. In some cases, the co-phase granularity of the wideband uplink precoders in the codebook 205 may be relatively low (e.g., not very fine) . In some cases, modifying a conventional codebook to support frequency-selective precoders and finer uplink precoder inter-port co-phase granularity may greatly increase the size of the codebook, which may increase overhead when indicating precoders. In some cases, increasing the size of the codebook may increase complexity for other wireless devices in the wireless communications system 200. Further, modifying the first precoder indication 215 to support frequency-selective uplink precoders may result in variably-sized, and generally, significantly larger overhead. For example, the variably-sized overhead may be very large in cases of many subbands and fine co-phase granularity. Further, some aspects of DCI signaling fixed overhead (e.g., if the first precoder indication 215 is transmitted over DCI) may facilitate implementation.

UE 115-a and base station 105-a may therefore support a two-stage precoder indication. For the first stage, base station 105-a may transmit the first precoder indication 215, and UE 115-a may identify a precoder (e.g., a first stage, wideband uplink precoder) from the codebook 230 (e.g., uplink precoders in a TPMI codebook may be used to indicate a first stage wideband uplink precoder) . The base station 105-a may also transmit a second stage uplink precoder indication 220 that is associated with indication 215. The second stage uplink precoder indication 220 may identify finer inter-port co-phase granularity (e.g., smaller than

) , and may be wideband or subband specific (e.g., to support frequency-selective precoding) . In some cases, the second stage uplink precoder indication 220 may provide an indication of finer co-phase granularity among different pairs of antenna ports. Additionally, or alternatively, the second stage uplink precoder indication 220 may provide a frequency selective indication of subband-specific co-phase among different antenna ports, which may be based on the first stage wideband uplink precoder.

The signaling used by base station 105-a to transmit the second stage uplink precoder indication 220 may be based on one of multiple different configurations. For non-configured-grant transmission schemes, the indication of the second stage uplink precoder indication 220 may be transmitted in DCI scheduling an uplink shared channel (e.g., PUSCH) . In the case of configured-grant transmission schemes, the second stage uplink precoder indication 220 may be RRC configured, indicated in DCI, or a combination thereof. For example, the base station 105-a may indicate possible uplink precoder configurations via RRC and/or may transmit an indicator for one of the uplink precoder configurations in DCI when activating an uplink shared channel transmission. In some cases, the second stage uplink precoder indication 220 may be carried in the same DCI as the first stage uplink precoder indication 215, or the second stage uplink precoder indication 220 may be conveyed in a separate DCI which may be associated with the DCI carrying the first stage uplink precoder indication 215.

In some examples, the second stage uplink precoder indication 220 may be transmitted in a GC-DCI to provide a dynamic uplink precoder update. A payload for the second stage uplink precoder indication 220 may not be large, for example if the number of subbands is small, or the co-phase granularity is not very fine (e.g.,

) . Therefore, the overhead of attaching a CRC for a small payload may be inefficient for UE-specific DCI. To reduce overhead, one or more precoder configurations or choices may be configured via RRC, and base station 105-a may transmit GC-DCI to indicate an uplink precoder from the RRC-configured set of precoders. For example, multiple UEs 115 may be configured with a GC-RNTI and respective GC-DCI offsets. UE 115-a may receive the GC-DCI, attempt to decode the GC-DCI using the GC-RNTI, and search for information specific to UE 115-a based on the GC-DCI offset configured for UE 115-a. Additional examples of transmitting the second stage uplink precoder indication 220 via GC-DCI are described in more detail with reference to FIG. 3.

In some cases, the techniques described herein may support that the overhead of the uplink precoder indication is fixed. For example, base station 105-a may transmit a second stage uplink precoder indication 220 to UE 115-a with a fixed payload size. In some cases, using a fixed payload size may be advantageous for transmitting the second stage uplink precoder indication 220 in DCI. However, if the number of subbands is large, it may not be possible to indicate all subband uplink precoders with fine granularity while using a small fixed overhead. Therefore, either co-phase granularity or the number of subbands may be adjusted (e.g., compromised) to fit in the fixed indication overhead.

In some implementations, base station 105-a may flexibly alter the co-phase granularity to accommodate a large number of subbands. These techniques are also described in more detail with reference to FIG. 4. When altering the co-phase granularity to support a large number of subbands, base station 105-a may configure, or generate, a payload of the uplink precoder indication based on one or more parameters. The parameters may include the payload size (e.g., in a number of bits) , a minimum wideband co-phase indication granularity, a minimum subband co-phase indication granularity, a number of subbands for frequency selective co-phase indication, or any combination thereof. In some cases, base station 105-a may configure (e.g., and indicate) these parameters over RRC, base station 105-a may indicate the parameters in DCI, or the parameters may be pre-configured by the network in the wireless communications system 200. In some cases, the parameters may be standardized or pre-configured in a standard, UE 115-a and base station 105-a may identify the parameters based on pre-configuration or the standard.

In some cases, there may be more than one UE interpretation of the payload when altering co-phase granularity to fit a large number of subbands. UE 115-a may check through the different possible cases of how the payload may be configured to determine which one was used by base station 105-a to generate the payload. The ways UE 115-a interprets a payload of the second stage uplink precoder indication 220 may be based on one or more payload interpretation rules. Depending on which of the different criteria the configured parameters and payload satisfy, UE 115-a may apply a different payload interpretation rule to interpret the payload of the second stage uplink precoder indication 220. In some examples, base station 105-a may include one or more bits to indicate which of the cases was used to generate the payload, as discussed below with reference to FIG. 4.

In some implementations, the uplink precoder indication may indicate frequency selective precoders for a subset of the large set of subbands. For example, the uplink precoder indication may maintain a fine level of co-phase granularity but may not indicate a frequency selective co-phase for each configured subband (e.g., compromising the number of subbands to keep a fine co-phase granularity) . In these examples, the uplink precoder may be configured to meet a fixed wideband co-phase indication granularity and a fixed subband co-phase indication granularity. In some cases, the technique used (e.g., reducing co-phase granularity or indicating co-phases for only a subset of subbands) may be indicated via RRC or DCI signaling. Or, in some cases, the technique used may be pre-configured in memory at UE 115-a. Or, in some cases, the technique used may be based on the parameters and may be determined by UE 115-a based on the parameters, channel conditions, network conditions, or any combination thereof.

UE 115-a may interpret a payload of the indicated frequency selective uplink precoders in different ways when reducing the number of selected subbands to meet the fixed wideband and subband co-phase granularities. In some examples, the way UE 115-a interprets a payload of the second stage uplink precoder indication may be based on one or more payload interpretation rules. Depending on which of the different criteria the payload satisfies, UE 115-a may apply a different payload interpretation rule. These techniques are also described in more detail with reference to FIG. 5.

The precoders indicated using these techniques to support fixed overhead may similarly be preconfigured (e.g., preconfigured choices) as described above, which may further reduce signaling overhead and support fixed overhead for uplink precoder indication. For example, these techniques may be directly applied to the GC-DCI techniques for non-configured-grant PUSCH or they may be applied for UE-specific DCI. Additionally, the precoders identified for each of the following indication options or configurations may be indicated as a potential choice of two stage uplink precoder information included in GC-DCI (e.g., for configured-grant PUSCH) .

FIG. 3 illustrates an example of a GC-DCI configuration 300 that supports frequency selective uplink precoder indication in accordance with aspects of the present disclosure. In some examples, the GC-DCI configuration 300 may implement aspects of wireless communication system 100.

As described with reference to FIG. 2, a UE 115 may precode uplink information to support enhanced beamforming techniques. The UE 115 may receive a first stage uplink precoding indication from a base station 105 and identify a precoder in a codebook based on the indication. The devices described herein may support a two-stage precoding indication, where the base station 105 may send the first stage uplink precoder indication and a second stage uplink precoder indication. The first stage uplink precoder indication may identify an uplink precoder (e.g., a wideband uplink precoder with less fine granularity) based on a conventional TPMI codebook. The second stage uplink precoder indication may indicate finer co-phase granularity than the precoders in the conventional codebook. UEs 115 and base stations 105 may support both wideband co-phase configurations and frequency selective, subband-specific co-phase configurations. The following describes different configurations and schemes for dynamically updating an uplink precoder via a GC-DCI 305.

In some cases, a payload for an uplink precoder indication may not be very large. For example, the payload may be small if the number of subbands is small, or the co-phase granularity is not very fine, or both. In these cases, the overhead for attaching a CRC may not be efficient when signaling the uplink precoder indication with a small payload using UE-specific DCI. Therefore, in some cases, the uplink precoder indication may be transmitted in a GC-DCI 305, which may reduce the overhead for the second stage uplink precoder indication.

In some cases, a UE 115 may be RRC configured with a GC-RNTI and a GC-DCI search offset that provides the location of information corresponding to the UE 115 (e.g., UE-specific information 315) within the GC-DCI 305. The base station 105 may indicate the second stage uplink precoder information in a GC-DCI 350 by including UE-specific information 315 for the UE 115 according to the GC-DCI search offset. The base station 105 may scramble the CRC 310 of the GC-DCI 305 using the GC-RNTI.

A UE 115 may monitor a search space for the GC-DCI 305 based on (e.g., associated with) the GC-RNTI and attempt to read the second stage uplink precoder information based on the search offset accordingly. For example, the UE 115 may decode the received GC-DCI and use the information bits from the GC-DCI to compute the CRC. If the CRC check passes, the UE 115 may determine that there may be information in the GC-DCI for the UE 115. The UE 115 may use its UE-specific search offset to obtain its information bits from the GC-DCI 305. The UE-specific information 315 may include second stage uplink precoder information for the UE 115. Or, in some cases, the UE-specific information 315 may include an indicator for a pre-configured second stage uplink precoder configuration (e.g., configured earlier via RRC signaling 325) . In some examples, these techniques may be applied for at least non-configured grant transmission schemes.

In one example, a first UE 115 (e.g., “UE0” ) may receive an RRC message for an RRC configuration from a base station 105. The RRC message may indicate a GC-RNTI and a GC-DCI search offset specific to UE0 which enables UE0 to determine where in the GC-DCI 305 that UE0 can identify the UE-specific information 315 for UE0. Based on the GC-RNTI, UE0 may monitor for and receive the GC-DCI 305 from the base station 105. UE0 may then attempt to decode the GC-DCI 305 using the GC-RNTI to descramble the CRC 310 of the GC-DCI 305. If UE0 determines the CRC check is successful, then UE0 may determine that there is information relating to UE0 in GC-DCI 305. UE0 may identify the UE-specific information in the GC-DCI based on the RRC-configured GC-DCI search offset for UE0 and read the UE-specific information 315 to determine second stage uplink precoder information.

In some cases, including some cases for non-configured-grant transmission, the UE-specific information 315 may include a full payload for a second stage uplink precoder indication. For example, based on the information in the UE-specific information, a UE 115 may determine frequency-selective and fine granularity uplink precoders for precoding and transmitting uplink information. In some cases, UE-specific information 315 may indicate co-phases for one or more subbands with a fine granularity. Additionally, or alternatively, the UE-specific information 315 may also indicate a wideband co-phase with fine granularity. In some examples, the UE-specific information may convey second stage uplink precoder information based on one or more criteria described with reference to FIGs. 4 and 5.

For some configured-grant transmission schemes, a UE 115 may be RRC configured with a GC-RNTI and a GC-DCI search offset that provides the location of information corresponding to the UE 115 the GC-DCI 305. The base station 105 may configure multiple configurations, or choices, for the second stage uplink precoder information in the RRC signaling 325. For example, the base station 105 may indicate various configurations for precoders that apply to certain subbands in the RRC and each configuration is associated with a different index. In some cases, the base station 105 may configure the second stage uplink precoder configurations during RRC configuration of a configured-grant PUSCH (e.g., when the base station 105 establishes the configured-grant transmission scheme or resources) . In an example, a first configuration may indicate a first precoder for a first subband, a second precoder for a second subband, and a third precoder for a third subband. A second configuration may indicate another set of precoders (e.g., with some or no common precoders) for a same or different set of subbands. In some cases, the different configurations may have different co-phase values. In some cases, each of the configurations may be associated with a different bit combination or index, which may be signaled in a bit field in the GC-DCI 305.

During PUSCH transmissions (e.g., configured-grant PUSCH transmissions) , the base station 105 may indicate one of the preconfigured second stage uplink precoder configurations in a GC-DCI. The base station 105 may indicate one of the RRC-configured second stage uplink precoder information configurations in a GC-DCI 305 by indicating the index associated with the configuration. The base station 105 may generate the GC-DCI, including the UE-specific information for each UE 115, based on the GC-DCI search offsets for the UEs 115 and scramble the CRC 310 of the GC-DCI 305 using the GC-RNTI. The base station 105 may place each UE’s configuration update according to the preconfigured GC-DCI search offsets to generate the GC-DCI 305.

A UE 115 may monitor a search space for the GC-DCI for the configured-grant PUSCH transmission based on the GC-RNTI. In some cases, the UE 115 may monitor a search space associated with the GC-RNTI. The UE 115 may receive and decode the GC-DCI, using the information bits from the GC-DCI to check the CRC 310. If the CRC computed by the UE 115 matches the expected CRC (e.g., the CRC check passes) , then there may be information in the GC-DCI 305 for the UE 115. The UE 115 may then read the second stage uplink precoder information in the UE-specific information 315 of the GC-DCI 305 based on the preconfigured offset for the UE 115. The UE-specific information 315 may point to one of the configurations, or choices, for the second stage uplink precoders which were configured by RRC. The UE 115 may read its second stage uplink precoder update and apply the uplink precoder update when precoding uplink information.

In one example of the configured-grant transmission, the first UE 115 in the GC-DCI ( “UE0” ) may receive an RRC message to establish the configured-grant transmission scheme that includes multiple configurations of the second stage uplink precoder information such as at least a first configuration 320-a (e.g., “configuration-0” ) , a second configuration 320-b (e.g., “configuration-2” ) , and a third configuration 320-c (e.g., “configuration-1” ) .

The following is an example of parameters in at least one RRC message that configures a PUSCH Grant for UE0:

GC-RNTI

GC-DCI search offset = 0.

Configurations of 2 ^nd Stage UL Precoder Information

Configuration-0

Precoder for SB-#0

Precoder for SB-#1

Precoder for SB-#2

.......

Configuration-1

Precoder for SB-#0

Precoder for SB-#1

Precoder for SB-#2

.......

Configuration-2

Precoder for SB-#0

Precoder for SB-#1

Precoder for SB-#2

.......

Configuration-3

Precoder for SB-#0

Precoder for SB-#1

Precoder for SB-#2

.......

In some cases, the RRC message may configure additional or fewer possible uplink precoder information configurations. Each configuration may indicate at least one precoder for at least one subband. In some cases, a configuration may include information for subband-specific precoders (e.g., subband-specific co-phases) , information for a wideband precoder (e.g., a wideband co-phase) , information for differential subband co-phases, or a combination thereof. UE0 may also be configured with a GC-RNTI and a GC-DCI search offset (e.g., a search offset of ‘0’ for UE0) . In some cases, the uplink precoders configured by RRC and indicated by GC-DCI may have a finer granularity than precoders in a conventional codebook. The UE 115 may then update its uplink precoder for an upcoming uplink transmission based on the uplink precoder indicated by the GC-DCI dynamic uplink precoder update.

The UE 115 (e.g., “UE0” ) may receive a GC-DCI 305, decode the transmission and determine that there is UE-specific information 315 for UE0 at a specific location based on the GC-DCI search offset for UE0. /UE0 may use the UE-specific information 315 to determine the updated uplink precoder configuration. The UE-specific information 315 may include a certain number of bits (e.g., 2 bits, which may have values of 00, 10, 01, or 11) which may correspond to a particular uplink precoder configuration that was pre-configured by RRC signaling. For example, the bits in the UE-specific information 315 may be ‘00’ which may be associated with first configuration 320-a (e.g., “configuration-0” ) indicated by RRC signaling. In some cases, the first configuration 320-a may indicate specific precoders for particular subbands. The UE 115 may then apply the uplink precoders as indicated by the first configuration 320-a when precoding uplink transmissions. In other examples, the UE-specific information 315 may include bits ‘10’ which may be associated with the second configuration 320-b or may include bits ‘01’ which may be associated with the third configuration 320-c.

FIG. 4 illustrates examples of uplink

precoder indication configurations

400, 401, 402, and 403 that support frequency selective uplink precoder indication in accordance with aspects of the present disclosure. In some examples, the uplink

precoder indication configurations

400, 401, 402, and 403 may implement aspects of wireless communication system 100.

As described with reference to FIG. 2, a UE 115 may precode uplink information to provide enhanced beamforming techniques. The UE 115 may receive an uplink precoding indication from a base station 105 such that the UE 115 may identify a precoder in a codebook based on the indication. The uplink precoding indication may be transmitted in two stages including a first stage uplink precoder indication and a second stage uplink precoder indication. The first stage uplink precoder indication may indicate precoders based on a conventional TPMI codebook. The second stage uplink precoder may indicate an uplink precoder with a finer granularity co-phase than the uplink precoders included in the conventional codebook. The second stage uplink precoder indication may indicate wideband or subband specific co-phases (e.g., frequency-selective precoder indication) .

If a UE 115 supports multiple subbands with a fine co-phase granularity, frequency-selective uplink precoder indication may lead to significant overhead. For example, the base station 105 would use a large number of bits to indicate a fine co-phase granularity for each subband in the second stage uplink precoder indication. Therefore, to prevent significant overhead for a payload 405 of the second stage uplink precoder indication due to fine co-phase granularity and a large number of supported subbands, the UE 115 and base station 105 may use a fixed overhead for the payload 405 of the second stage uplink precoder indication. The UE 115 and base station 105 may implement techniques to provide frequency-selective precoders with fine co-phase granularity while still considering a fixed overhead for the second stage uplink precoder indication. The UE 115 and base station 105 may implement such techniques while using GC-DCI or UE-specific DCI. In some cases, a configuration for the payload 405 for the second stage uplink precoder indication may be based on a transmission type configured for the UE 115.

The payload 405 of the second stage uplink precoder indication may be configured for frequency selective co-phase indication, for wideband finer co-phase indication, or both. The payload 405 may be a DCI payload if DCI is used for the first and/or second stage uplink precoder indication. Or, the payload 405 may be an RRC payload if the payload 405 is transmitted in an RRC message. For example, the payload 405 may be transmitted as part of an RRC pre-configuration scheme for configured-grant PUSCH transmissions, where the uplink precoder may be indicated by a single precoder configuration indication.

The base station 105 may configure the payload 405 based on a set of parameters associated with flexibly altering a co-phase granularity to fit in a large number of subbands. The parameters may be configured by the base station 105 and indicated to the UE 115 via RRC or DCI, or the parameters may be pre-configured and stored in memory at the UE 115. In some cases, the parameters may be pre-determined in a standard and stored in memory at the UE 115. In some cases, the parameters may include a size of the payload 405 (e.g., as a number of bits) . In some cases, the parameters may include a minimum wideband co-phase indication granularity and a minimum subband co-phase indication granularity, where the subband co-phase indication granularity may be the same or finer than the wideband co-phase indication granularity. In an example, by use of the term minimum, the payload may be at least the minimum number of configured indication bits (e.g., wideband co-phase indication is at least one 1 bit, subband co-phase indication is least one 2 bits per subband) . In some examples, the parameters may indicate a number of subbands for frequency selective co-phase indication. Due to a fixed payload size and the different parameters to convey, there may be different possible interpretations of the payload 405 by the UE 115.

The following uplink precoder indication configurations show some example payload configurations of the second stage uplink precoder indication. The

configurations

400, 401, 402, and 403 may generally support flexibly altering a co-phase granularity to fit in a large number of subbands. In some cases, the uplink precoders identified by each indication option may be an example of a potential configuration, or choice, for second stage uplink precoder information as defined by, or described with reference to, GC-DCI. Or, in some cases, the uplink precoders may be indicated by a UE-specific DCI.

The payload 405 may be configured according to an uplink precoder indication configuration based on a criterion (e.g., a co-phase indication granularity criterion) for a corresponding case being met. A base station 105 (e.g., generating the payload 405) may determine which configuration to use to generate the payload 405 based on the set of parameters and which of the criterion the set of parameters meet as discussed in the following cases. Therefore, the case which is used (e.g., corresponding to either the uplink

precoder indication configuration

400, 401, 402, or 403) may be the result of the set of parameters meeting the criterion of the corresponding case being met. The UE 115 may implement techniques to determine which configuration, and therefore case, to which the payload 405 corresponds. Or, in some cases, the base station 105 may include one or more bits in the payload 405, a header, or another signal to indicate which of the configurations was used to generate the payload 405.

The UE 115, configured with the parameters, may receive a payload 405 from a base station 105 and attempt to determine, based on the parameters, which case was used to generate the payload 405. In some cases, the UE 115 may sequentially apply at least one criterion for the different cases in a particular order, or may check two or more of the criteria in parallel, until at least one criterion from the set of different possible criteria is satisfied. In some cases, sequentially applying the criterion may provide some advantages for the UE 115, as the UE 115 may check cases with the finest granularity first. If the UE 115 generally uses the finest granularity uplink precoder when available, this may reduce the processing time for UE 115 to determine which case was used to generate the payload 405. In some examples, the UE 115 may apply the criterion in parallel to determine which case was used to generate the payload 405.

For example, the UE 115 may determine whether the set of parameters meets the criterion of the first case corresponding to configuration 400. If the set of parameters meets the criterion of the first case, then the UE 115 may implement the first case and thus attempt to interpret the payload 405 using an interpretation rule corresponding to the first configuration (e.g., uplink precoder indication configuration 400) . If the set of parameters does not meet the criterion of the first case, the UE 115 may determine whether the payload 405 meets the criterion of the second case. If the set of parameters does not meet the criterion of the second case, the UE 115 may determine whether the criterion of the third case is met. The UE 115 may continue in this manner until the UE can determine the set of parameters meets criterion of a configured case. In some examples, if the set of parameters does not meet the criterion for any of the configured cases, the UE 115 may determine that there was an error for the payload 405, and the UE 115 may respond with a negative acknowledgment (NACK) . Each configured case may be associated with a level of specificity and granularity, such that the first case may provide the configuration with the most specific indication and in some cases, the highest granularity. In some examples, the level of specificity and indication granularity may decrease with increasing case numbers.

In some of the following examples, a UE 115 may be configured with a certain set of parameters. For example, the payload 405 may be configured to include 12 bits (e.g., the payload 405 is 12 bits long) . The UE 115 may be configured with three inter-port-pairs. In some examples, the parameters may indicate that the payload 405 is to use at least one bit per inter-port pair to meet a minimum wideband co-phase indication granularity. Therefore, in this example, to include a wideband co-phase indication with the minimum wideband indication granularity, the payload 405 may use at least three bits. In some examples, configured parameters may specify for the payload 405 to use at least two bits per inter-port-pair to satisfy the minimum subband indication granularity per inter-port-pair. Therefore, in this example, a subband-specific co-phase indication which meets the minimum subband-specific co-phase indication granularity may use 6 bits (e.g., 2 bits per inter-port pair for the three configured inter-port pairs) . In some examples, the parameters may be standardized, and the UE 115 may identify the parameters based on the standard. In some cases, the parameters may be pre-configured in storage stored at the UE 115, and the UE 115 may identify the parameters from the storage at the UE 115.

Additionally, or alternatively, the parameters may specify for the payload 405 to use, per inter-port pair, at least one wideband bit and at least one bit per subband for an inter-port-pair to meet a differential subband minimum granularity (e.g., based on the minimum wideband co-phase indication granularity and the minimum subband indication granularity) . Therefore, in this example, according to these parameters, the payload 405 may include three bits for wideband co-phase indication which meets the minimum wideband co-phase indication granularity and three bits per differential subband co-phase indication which meets the minimum differential subband co-phase indication granularity.

The criterion of the first case may be that, by using all bits of the payload 405 to directly indicate co-phases for each of the subbands, the subband co-phase granularity may achieve a level equal to or better than the configured minimum subband co-phase indication granularity. If the first case can be met, the base station 105 may configure the payload 405 according to the first stage uplink precoder indication configuration 400. In this example, the UE 115 may be configured with two subbands. The uplink precoder indication configuration 400 may support direct subband-specific co-phase indication, as there may be enough bits in the payload 405 to directly indicate a co-phase for each configured subband with a finer granularity than the configured minimum subband co-phase indication granularity. For each subband, the same number of bits (e.g., in some cases as many as possible) may be used to indicate a subband specific co-phase for each subband such that each subband can be co-phase indicated with equal granularity.

The payload 405, configured based on the uplink precoder indication configuration 400, may then include co-phase indications 410 for each subband. For example, the payload 405 may include a first co-phase indication 410-a for subband #1 and a second co-phase indication 410-b for subband #2. According to the configured parameters described above (e.g., three inter-port-pairs) , the payload 405 may include 6 bits to indicate a co-phase for each of the three inter-port-pairs per subband. The 6 bits for the co-phase indications 410 may correspond to three inter-port pairs, with 2 bits of granularity per inter-port pair. Therefore, the payload 405 may use all 12 bits to indicate the subband-specific co-phases for both of the subbands, where the first co-phase indication 410-a for subband #1 has 6 bits, and the second co-phase indication 410-b for subband #2 also has 6 bits. The UE 115 may determine that the configured parameters are able to satisfy the co-phase granularity criterion of the first case. The UE 115 may then apply a payload interpretation rule corresponding to the first case to interpret the payload 405 in accordance with configuration 400 and retrieve information from the payload 405. In another example, if the payload 405 were 18 bits, the first case would support direct subband co-phase indication for up to 3 subbands.

The criterion of the second case may be that, while the UE 115 may determine that the configured parameters are unable to satisfy the criterion of the first case, the UE 115 may check whether configured parameters are unable to satisfy the criterion of the second case. In the second case, the payload 405 may at least be able to indicate a wideband co- phase which is at least as fine as the minimum wideband co-phase indication granularity, and the remaining bits of the payload may be used for subband-specific differential co-phase indication that satisfies the configured minimum subband differential co-phase indication granularity for each subband. For the second case, there may not be enough remaining bits in the payload 405 to achieve a granularity finer than the subband-specific co-phase indication granularity by using the first case. For example, using all of the payload 405 for subband-specific co-phase indication would achieve an indication granularity worse than the subband co-phase indication granularity minimum requirement. However, the payload 405 may include sufficient bits to indicate a wideband co-phase which is at least as fine as the minimum wideband granularity and sufficient remaining bits to indicate differential subband co-phases which, when used with the minimum wideband granularity, are at least as fine as the configured minimum differential subband indication granularity.

The uplink precoder indication configuration 401 may be an example of a payload 405 which is generated based on the configured parameters meeting the second case. In this example, the UE 115 may be configured with three subbands. The criterion of the second case may be that, by using all of the indication payload, subband co-phase granularity may achieve a level worse than the subband co-phase indication granularity minimum requirement. However, the configured wideband co-phase indication granularity minimum may at least be able to be met, and the remaining bits of the payload may be capable of subband differential co-phase indication which at least meets the differential subband co-phase indication granularity minimum.

For example, the bits of the payload 405 may not support subband-specific co-phase indication which meets the subband co-phase indication granularity minimum. However, a payload 405 that is configured in accordance with the second stage uplink precoder indication configuration 401 may have enough bits for a wideband co-phase indication to at least meet the minimum wideband co-phase indication granularity and, for each subband, there may be enough remaining bits of payload 405 to at least meet the configured differential subband co-phase indication granularity minimum requirement. In some cases, the payload 405, configured in accordance with the second stage uplink precoder indication configuration 401, may use the same number of bits (e.g., using all remaining bits) to indicate a subband co-phase, such that each subband may be co-phase indicated with a differential and equal co-phase granularity on top of (e.g., when used alongside) the wideband co-phase indicated by wideband indication 415. For example, the indicated wideband co-phase may be a first co-phase on a quadrature phase-shift keying (QPSK) grid. The differential indications 420 may then indicate, based on the first co-phase, a finer subband-specific co-phase for the inter-port antenna pairs. For example, the differential indication 420 may indicate a phase change or delta from the first co-phase, which the UE 115 can use to identify a second co-phase.

The uplink precoder indication configuration 401 may include a wideband indication 415, a first differential indication 420-a for a first subband (e.g., subband #1) , a second differential indication 420-b for a second subband (e.g., subband #2) , and a third differential indication 420-c for a third subband (e.g., subband #3) . In this example, the configured minimum wideband co-phase indication granularity per inter-port-pair may be one bit, such that three bits may be included in the wideband indication 415 for the three inter-port-pairs. After the minimum wideband co-phase granularity is met, there are nine remaining bits in payload 405, which may be used for differential co-phase indication. The minimum differential subband co-phase granularity per inter-port-pair may be one bit for the wideband and one bit per subband, such that each subband takes three bits to satisfy the configured minimum differential subband co-phase indication granularity for the three inter-port-pairs. Therefore, each differential indication 420 in the uplink precoder indication configuration 401 may include three bits for each subband, to differentially indicate the sub-band co-phase per inter-port pair. For example, the first differential indication 420-a for subband #1 may include three bits, one for each of the three configured inter-port-pairs for the first subband (e.g., subband #1) .

A UE 115 receiving the payload 405 configured based on the uplink precoder indication configuration 401 may determine, per each of the three configured inter-port-pairs, the wideband co-phase based on a respective bit in the wideband indication 415, and then determine a subband co-phase for each subband based on the corresponding bits in the differential indicators 420. For a first inter-port-phase, the wideband indicator may, for example, indicate a first co-phase (e.g., π/2) . A bit in the first differential indication 420-a may indicate a differential co-phase for the first subband for the inter-port-pair. For example, from the wideband co-phase, the co-phase for the inter-port-pair may either be 3π/4 or 5π/4, or some other subband co-phase which at least is finer than, or as fine as, the minimum subband co-phase indication granularity requirement.

The criterion of the third case may be that the parameters are configured such that the payload 405 can support wideband co-phase indication meeting the wideband indication granularity minimum, and the remaining payload bits (e.g., after including the wideband indication) may not be capable of meeting the subband differential co-phase indication with at least the configured minimum subband co-phase indication granularity. The payload 405 thus may not be able to meet the criteria of the first case or the second case. In some cases, the UE 115 may determine the payload 405 meets the criterion of the third case after determining that the payload 405 does not meet the criteria of the first and second cases. In some cases, the UE 115 may perform parallel processing for each respective criterion.

The third case may correspond to uplink

precoder indication configurations

402 and 403. In these examples, the UE 115 may be configured with four subbands. The UE 115 may determine that, by using all bits of the payload 405, direct subband co-phase indication or differential subband co-phase indication (e.g., as described in the first and second examples) may not meet at least the configured minimum subband co-phase indication granularity. The UE 115 may then determine that the payload 405 meets the third case and was configured similarly to the uplink

precoder indication configuration

402 or 403. In some cases, the payload 405 may use as many bits of the payload 405 to indicate a wideband co-phase with the minimum wideband co-phase indication granularity.

In this case, there may be bits remaining after indicating the wideband co-phase. For example, uplink precoder indication configuration 402 may include a wideband indication 425, and the remaining bits after reaching the minimum wideband co-phase granularity may be reserved bits 430. In some other examples, the payload 405 may use as many bits as possible to indicate the wideband co-phase with maximized co-phase granularity. For example, uplink precoder indication configuration 402 may include a first inter-port-pair wideband indication 435-a for a first inter-port-pair, a second inter-port-pair wideband indication 435-b for a second inter-port-pair, and a third inter-port-pair wideband indication 435-c for a third inter-port-pair. By maximizing the use of and equally distributing the 12 bits in the payload 405 among the three configured inter-port-pairs, the base station 105 may, in this example, indicate the wideband co-phase for each inter-port-pair by using 4-bits.

FIG. 5 illustrates examples of uplink

precoder indication configurations

500, 501, 502, 503, and 504 that support frequency selective uplink precoder indication in accordance with aspects of the present disclosure. In some examples, uplink

precoder indication configurations

500, 501, 502, 503, and 504 may implement aspects of wireless communication system 100.

As described with reference to FIG. 2, a UE 115 may precode uplink information to provide enhanced beamforming techniques. The UE 115 may receive an uplink precoding indication from a base station 105 such that the UE 115 may identify a precoder in a codebook based on the indication. The uplink precoding indication may be transmitted in two stages including a first stage uplink precoder indication and a second stage uplink precoder indication, which may indicate an uplink precoder with a finer granularity co-phase than the uplink precoders included in the conventional codebook. The second stage uplink precoder indication may indicate wideband or subband specific co-phases (e.g., frequency-selective precoder indication) .

If a UE 115 supports multiple subbands with a fine co-phase granularity, frequency-selective uplink precoder indication may lead to significant overhead. To reduce overhead, the UE 115 and base station 105 may use a fixed overhead (e.g., a small fixed overhead in some cases) for the payload 505 of the second stage uplink precoder indication. The UE 115 and base station 105 may implement techniques to provide frequency-selective precoders with relatively fine co-phase granularity while still considering a fixed overhead for the second stage uplink precoder indication. The UE 115 and base station 105 may implement such techniques while using GC-DCI or UE-specific DCI. In some cases, a configuration for the payload 505 for the second stage uplink precoder indication may be based on a transmission type configured for the UE 115.

The base station 105 may generate the payload 505 based on a set of parameters associated with selecting subbands of a set of subbands to achieve the fixed overhead with fixed granularity requirements. The parameters may be configured by the base station 105 or be pre-configured. In some cases, the base station 105 may configure the UE 115 with the parameters (e.g., by transmitting an indication of the parameters to the UE 115) via RRC, the base station 105 may indicate the parameters to the UE 115 via DCI, or both. In some cases, if the parameters are pre-configured for the network, the UE 115 may have one or more of the parameters pre-configured in memory.

In some examples, the parameters may include a size of the payload 505 (e.g., as a number of bits) . The payload 505 may be a DCI payload 505 if DCI is used for the indication, or the payload 505 may be an RRC payload if the payload 505 is transmitted over RRC. In some cases, the parameters may include a number of inter-port pairs (e.g., 3 inter-port pairs) , a payload size (e.g., a number of bits in payload 505, e.g., 12 bits) , a fixed wideband co-phase indication granularity (e.g., wideband granularity per inter-port-pair, e.g., 1 bit per inter-port pair) , a fixed subband co-phase indication granularity per inter-port pair (e.g., 2 bits, per subband uses 6 bits for 3 inter-port pairs) , a fixed differential indication granularity (e.g., 1 bit wideband plus 1 bit per subband) , where the fixed subband co-phase indication granularity and/or the fixed differential subband co-phase indication granularity is at least as fine as the fixed wideband co-phase indication granularity. By use of the term fixed, the payload may, in an example, have that number of configured bits (e.g., wideband co-phase indication is fixed to be 1 bit, subband co-phase indication is fixed to be 2 bits per subband) . In some examples, the parameters may indicate a number of subbands for frequency selective co-phase indication. In some examples, the parameters may be standardized, and the UE 115 may identify the parameters based on the standard. In some cases, the parameters may be pre-configured in storage stored at the UE 115, and the UE 115 may identify the parameters from the storage at the UE 115.

The following uplink precoder indication configurations show some examples of indicating precoders for multiple subbands while still maintaining a high level of co-phase granularity. The uplink

precoder indication configurations

500, 501, 502, 503, and 504 may generally support indicating a co-phase for a subset of configured subbands to achieve the fixed overhead with fixed indication granularity requirements. Generally, these techniques describe compromising the number of subbands which are co-phase indicated to maintain a high granularity of co-phase indication.

The payload 505 may be configured according to one of the uplink precoder indication configurations based on the payload 505 meeting a criterion for a corresponding case. A base station 105 (e.g., generating the payload 505) may determine which configuration to use to generate the payload 505 based on the set of parameters and how the set of parameters applies to the criterion of the different cases. Therefore, the case which is used (e.g., corresponding to either the uplink

precoder indication configuration

500, 501, 502, 503, or 504) may be the result of the criterion of the corresponding case being met. The UE 115 may implement techniques to determine which configuration, and therefore case, to which the payload 505 corresponds. Or, in some cases, the base station 105 may include a set of bits to indicate which of the configurations was used to generate the payload 505. In some cases, the uplink precoders identified by each indication option may be an example of a potential configuration, or choice, for second stage uplink precoder information as defined by, or described with reference to, GC-DCI. Or, in some cases, the uplink precoders may be indicated by a UE-specific DCI.

The UE 115, configured with the parameters, may receive the payload 505 from the base station 105 and attempt to determine which criterion the payload 505 meets. In some cases, the UE 115 may check the criteria sequentially in a particular order or may check two or more of the criteria in parallel. For example, the UE 115 may first determine whether the payload 505 meets the criterion of the first case. If the payload 505 does meet the criterion of the first case, then the UE may implement the first case and thus attempt to decode the payload 505 according to the first configuration (e.g., uplink precoder indication configuration 500) . If the payload 505 does not t meet the criterion of the first case, the UE 115 may determine whether the payload 505 meets the criterion of the second case. If the criterion of the second case is not met by the payload 505, the UE 115 may determine whether the criterion of the third case is met. The UE may continue in this manner until the UE can determine the payload 505 meets criterion of a configured case. In some examples, if the payload 505 does not meet the criterion for any of the configured cases, the UE 115 may determine that there was an error for the payload 505, and the UE 115 may respond with a NACK. Each configured case may be associated with a level of specificity and granularity, such that the first case may provide the configuration with the most specific indication and in some cases, the highest granularity. In some examples, the level of specificity and indication granularity may decrease with increasing case numbers.

In some of the following examples, a UE 115 may be configured with a certain set of parameters. For example, the payload 505 may be configured to include 12 bits (e.g., the payload 505 is 12 bits long) . The UE 115 may be configured with three inter-port-pairs. In some examples, the parameters may indicate that one bit is to be used per inter-port pair to indicate a wideband co-phase with a wideband indication granularity (e.g., the fixed wideband co-phase indication granularity is fixed to be one bit) . In some examples, the parameters may be configured such that two bits are to be used per inter-port-pair to indicate subband co-phases with the fixed subband indication granularity per inter-port-pair. In the depicted example, the payload 505 may use 6 bits per subband to indicate a subband-specific co-phase with the fixed subband-specific co-phase indication granularity (e.g., 2 bits per inter-port-pair with three inter-port-pairs for each subband) . Additionally, or alternatively, the payload 505 may include, per inter-port pair, one wideband bit and one bit per subband for an inter-port-pair to meet the configured fixed differential subband indication granularity. In other examples, the parameters may have different co-phase indication granularities, inter-port-pairs, or payload sizes.

The criterion of the first case may be that, by using all bits of the payload 505, the subband co-phase indication granularity may achieve the fixed subband co-phase indication granularity. If the criterion of the first case can be met, the base station 105 may configure the payload 505 according to the uplink precoder indication configuration 500. In this example, the UE 115 may be configured with two subbands. The uplink precoder indication configuration 500 may be capable of direct subband-specific co-phase indication, as there may be enough bits in the payload 505 to indicate a co-phase for each configured subband that satisfies the fixed subband co-phase indication granularity. Therefore, for each subband, the same number of bits may be used to indicate co-phases, such that each subband is indicated with the fixed subband co-phase indication granularity of subband co-phase. Compared to the first case described with reference to FIG. 4, in some cases the first case here may not use as many bits as possible, instead configuring the indication to include the same number of bits as indicated by the configured fixed subband co-phase indication granularity.

The payload 505, configured based on the second stage uplink precoder indication 500, may then include co-phase indications 510 for each subband. For example, the payload 505 may include a first co-phase indication 510-a for a first subband (e.g., subband #1) and a second co-phase indication 510-b for a second subband (e.g., subband #2) . The parameters may be configured such that the payload 505 includes 6 bits to indicate a co-phase for of the inter-port-pairs per subband (e.g., a fixed 2 bit indication granularity for each of three inter-port-pairs) . Therefore, the payload 505 may use all 12 bits to indicate the subband specific co-phases for the two subbands with the fixed subband co-phase indication granularity, where the first subband co-phase indication 510-a has 6 bits, and the second subband co-phase indication 510-b has 6 bits.

The criterion of the second case may be that, using all of the indication payload, subband co-phase granularity may achieve a level worse than the fixed subband co-phase indication granularity. Thus the criterion of the first case may not be met, and the parameters may be configured such that the payload 505 is able to indicate a wideband co-phase which meets the fixed wideband co-phase indication granularity requirement, and any remaining bits of the payload 505 may be capable of subband differential co-phase indication with the fixed differential subband co-phase indication granularity. In some cases, the remaining bits may be capable of subband differential co-phase indication that satisfies the configured fixed differential subband co-phase indication granularity requirement.

In some examples, the UE 115 may determine the configured parameters are able to meet the criterion of the second case after determining that the payload 505 and configured parameters are not capable of meeting the first case. If the configured parameters for payload 505 can meet the criterion of the second case, the payload 505 may be configured in accordance with the uplink precoder indication configuration 501. For example, if using all bits of the payload 505 for direct subband co-phase indication (e.g., as described in the first example) does not satisfy the fixed subband co-phase indication granularity, the base station 105 may determine whether to configure the uplink precoder indication according to the second case. In this example, the UE 115 may be configured with three subbands.

The second stage uplink precoder indication configuration 501 may have enough bits in payload 505 for a wideband co-phase indication to meet the configured fixed wideband co-phase indication granularity for indicating wideband co-phase. For each subband, the same number of bits (e.g., using the remaining bits after wideband co-phase indication) may be used to indicate a differential subband co-phase, such that each subband may be indicated with a differential subband co-phase indication granularity that satisfies the configured fixed differential subband co-phase indication granularity on top of (e.g., when used alongside) the indicated wideband co-phase.

For example, uplink precoder indication configuration 501 may include a wideband indication 515, a first differential indication 520-a for a first subband (e.g., subband #1) , a second differential indication 520-b for a second subband (e.g., subband #2) , and a third differential indication 520-c for a third subband (e.g., subband #3) . In this example, the configured fixed wideband co-phase indication granularity per inter-port-pair may be one bit, such that three bits are used for the three inter-port-pairs. Therefore, the wideband indication 515 may include 3 bits. After the fixed wideband indication granularity requirement is met, there are nine remaining bits in the payload 505. The configured fixed differential subband co-phase indication granularity, per inter-port-pair, may be one bit for the wideband co-phase indication and one bit for differential subband co-phase indication. Therefore, each differential indication 520 in the uplink precoder indication configuration 501 may include three bits. The UE 115 may determine subband co-phase using a wideband bit from the wideband indication 515 and a bit for the differential indication 520 to determine subband co-phase for each inter port pair for each of the three subbands.

The criterion of the third case may be that, using all of the indication payload 505, a subband co-phase granularity may achieve a level worse than the fixed subband co-phase indication granularity, and that the configured fixed wideband co-phase indication granularity minimum requirement can be met by at least using all of the payload 505, but the number of bits remaining after wideband indication may not achieve the configured fixed subband co-phase indication granularity requirement if all subbands are indicated. For example, the remaining bits after reaching the wideband requirement may not be capable of meeting the fixed subband differential co-phase indication granularity if all subbands are indicated. While the payload 505 cannot meet the criteria of the first case or the second case, at least the fixed wideband co-phase indication granularity can be met in the third case.

The UE 115 may determine that the parameters are configured such that the uplink

precoder indication configurations

502, 503, and 504 are capable of meeting the fixed wideband co-phase indication granularity requirement but cannot meet the criteria for the first or second cases. For example, there may not be enough bits in the payload 505 for direct subband co-phase indication or differential subband co-phase indication for all subbands (e.g., as described in the first and second examples) which meets at least one of the fixed subband co-phase granularity or the fixed differential subband co-phase granularity. The UE 115 may determine that the payload 505 meets the criterion of the third case after determining that the payload 505 does not meet the criteria of the first and second cases. The third case may correspond to uplink

precoder indication configurations

502, 503, and 504. For these configurations, the UE 115 may be configured with four subbands. The base station 105 may generate the corresponding payloads 505 by firstly using the number of bits capable of indicating a wideband co-phase with the fixed wideband co-phase indication granularity. Afterward, the payloads 505 may support different schemes for selective subband co-phase indication, corresponding to the different uplink

precoder indication configurations

502, 503, and 504.

The third case may correspond to indicating co-phase for only a subset of configured subbands. In a first example, the subset of subbands may be indicated via bitmap for a subband index indication, which may correspond to the uplink precoder indication configuration 502. In a second example, the subset of subbands may be indicated via a subband selection pattern, which may correspond to the uplink precoder indication configuration 503. In a third example, the subset of subbands may be adaptively selected via adaptive subband selection corresponding to the uplink precoder indication configuration 504. These techniques may be implemented to achieve the configured fixed wideband co-phase indication granularity and/or the configured fixed differential subband co-phase indication granularity for the subset of configured subbands.

For the first example of the third case, the base station 105 may configure the payload 505 according to the subband index indication scheme, which may use some of the remaining number of bits (e.g., after bits of payload 505 are used for wideband indication 525) for a bitmap 530 indicating subband indices. The payload 505 may include a bitmap 530 indicating subband indices for which co-phase is indicated. The remaining bits (e.g., remaining after the wideband indication 525 and the bitmap 530) may be used to indicate a differential subband co-phase (e.g., based on the wideband indication 525) having the configured fixed differential subband co-phase indication granularity. The base station 105 may confirm that the number of subbands indicated in the bitmap (e.g., positive subbands) may meet the fixed differential subband co-phase indication granularity with the remaining bits when configuring payload 505. In some examples, the bitmap 530 may indicate positive and negative subband indexes for a set of subbands, where a first subband subset of the set of subbands with positive indexes are indicated with subband co-phases and a second subband subset of the set of subbands with negative indexes are not indicated with subband co-phases. In the depicted example where there are four configured subbands, bitmap 530 may indicate that subband (SB) #1 has a positive index, and SBs #2-#4 have negative indexes.

For example, the uplink precoder indication configurations 502 may include the wideband indication 525, and the remaining bits (e.g., nine bits) may be used for a four bit bitmap 530. Each index in the bitmap may correspond to one of the four configured subbands. The bitmap 530 may indicate the subband (s) that will be indicated in the uplink precoder indication configurations 502 with the remaining bits. In the illustrated example, there may be enough remaining bits to indicate a differential co-phase for one subband (e.g., such as differential indication 535 for subband #1) , and none of the other configured subbands. The configured fixed differential subband co-phase indication granularity may be one wideband bit plus one bit per subband across three inter-port-pairs. Therefore, the first differential indication 535 for subband #1 may use 3-bits, leaving two remaining bits in payload 505. The two remaining bits may not be enough to indicate a second differential co-phase, based on the fixed differential co-phase indication granularity, so the remaining two bits may not be used for a differential indication and may instead be reserved bits 540. The reserved bits 540 may, in some cases, be used for other signaling or to enhance the signaling described herein. The base station 105 may confirm that subbands selected can be differentially co-phase indicated in accordance with the configured fixed differential subband co-phase indication granularity when configuring the payload 505.

For the second example of the third case, the base station 105 may implement the subband selection pattern (e.g., bit pattern) option, which may use some of the remaining bits (e.g., after a wideband indication 545) to indicate one of a set of subband selection patterns. In some cases, candidate subband selection patterns may be preconfigured or be configured by the network via DCI or RRC signaling. The selection pattern may be specified by a combinatorial number, as one example. The remaining bits (e.g., remaining after wideband indication and subband selection pattern) may be used for differential subband co-phase indication for the selected subbands based on the fixed differential subband co-phase indication granularity. The base station 105 may confirm that the remaining bits can provide differential subband co-phase indication meeting the fixed differential subband co-phase indication granularity when configuring the payload 505.

For the second example, the uplink precoder indication configuration 503 may include the wideband indication 545, and the remaining bits (e.g., nine bits) may be used to indicate a bit pattern 550 using three bits. The bit pattern 550 may indicate some combination of two subbands from the four configured subbands (e.g.,

) , where the combinations may either be preconfigured for the UE 115 or configured by the network via DCI or RRC signaling. The bit pattern 550 may indicate subbands with co-phases indicated with the remaining bits in the payload 505 according to the uplink precoder indication configuration 503. In this example, there may be enough remaining bits to indicate two subbands, as the fixed differential subband co-phase indication granularity may indicate to use one wideband bit and one bit per subband. In this example, the bit pattern 550 may indicate that a first subband and a fourth subband are co-phase indicated. The UE 115 may process the bit pattern 550 to also determine that co-phase is not indicated for the other subbands, which are the second and third subbands in the depicted example. Therefore, the payload 505 configured according to the uplink precoder indication configuration 503 may include a first differential indication 555-a for the first subband and a second differential indication 555-b for the fourth subband. After the wideband indication 545, the bit pattern 550, and the differential indications 555, there may not be any remaining bits, and the 12 bit payload may be fully utilized.

For the third example of the third case, the base station 105 may implement an adaptive subband selection scheme which uses the remaining bits (e.g., remaining after the bits of payload 505 allocated for wideband indication) to indicate differential subband co-phases that meet the fixed differential subband co-phase indication granularity. As an example, starting from the nth subband, every (K + n) th, (2K + n) th, (3K + n) th, etc. of the configured subbands may be selected for co-phase indication, where the value of n may be specified in the standards, RRC configured, or indicated dynamically (e.g., DCI, a MAC CE) . UE 115 may determine the value of K such that the number of subbands indicated by the adaptive subband selection meets the fixed differential subband co-phase granularity with the remaining bits. In this option, the value of K may be based on a size of the payload 505. This way, adjacent subbands may have a fixed offset from the subband before it. In some cases, the base station 105 and UE 115 may agree upon the value of K. The indication of the selection of the subbands may not be necessary in the payload. The UE 115 may determine the indication is regarding the adaptively identified subbands based on previously agreed upon configurations.

For example, a payload 505 configured based on the uplink precoder indication configurations 504 may include a wideband indication 560 (e.g., 3 bits) , and the remaining bits (e.g., 9 bits) may be used for differential indications 565 for the subbands selected based on the adaptive subband selection scheme. The base station 105 may indicate three differential indications 565 because the configured fixed differential subband co-phase indication granularity may be one wideband bit per every one subband bit. Therefore, each differential indication 565 may use 3 bits. In this example, the value of n may be zero and the value of K may be one. There may be enough remaining bits (e.g., after the wideband indication 560) for the base station 105 to indicate three differential subband co-phases, including differential indication 565-a for a first subband, differential indication 565-b for a second subband, and differential indication 565-c for a third subband.

Subbands

1, 2, and 3 may have been selected based on the adaptive subband scheme to identify the (K + n) th, (2K + n) th, (3K + n) th, etc. where n = 0 and K = 1. In this example, base station 105 may not have sufficient bits to indicate a differential co-phase for the fourth subband in payload 505, as three differential indications fit in the remaining 12 bits of the payload 505, and thus payload 505 may not indicate differential co-phase for the fourth subband differential.

FIG. 6 illustrates an example of a process flow 600 that supports frequency selective uplink precoder indication in accordance with aspects of the present disclosure. In some examples, process flow 600 may implement aspects of wireless communication system 100. The process flow 600 may include UE 115-b and base station 105-b, which may be respective examples of a UE 115 and a base station 105 described herein. The process flow 600 may illustrate an example precoding indication scheme for precoding an uplink transmission. For example, base station 105-b may perform a precoding indication procedure and transmit uplink precoding indications to UEs 115-b in more than one stage, such as in a two stage uplink precoder indication scheme described herein. Alternative examples of the following may be implemented, where some steps are performed in a different order than described or are not performed at all. In some cases, steps may include additional features not mentioned below, or further steps may be added.

At 605, base station 105-b may transmit a first stage uplink precoder indication of wideband precoding to UE 115-a. At 610, base station 105-b may transmit a second stage uplink precoder indication of a first wideband co-phase granularity for the wideband precoding, a subband co-phase granularity for subband uplink precoding, or both to UE 115-b. In some cases, each of the first wideband co-phase and the subband co-phase granularity may be finer than a second wideband co-phase granularity indicated by the first stage uplink precoder indication. In some cases, base station 105-b may generate the second stage uplink precoder indication based on one or more of the uplink precoder configurations corresponding to one of the cases described with reference to FIGs. 4 and 5.

UE 115-b may receive control signaling as part of or separately from the first stage uplink precoder indication and second stage uplink precoder indication. The control signaling may configure UE 115-b with a group temporary identifier and a search offset. Additionally, or alternatively, the control signaling may configure UE 115-b with a set of different second stage uplink precoder configurations. UE 115-b may monitor a search space for the second stage uplink precoder indication based on the group temporary identifier and the search offset. Additionally or alternatively, UE 115-b may decode the search space to obtain DCI based on the group temporary identifier and the search offset. UE 115-b may select a first configuration from the set of different second stage uplink precoder configurations based on the DCI. In some examples, the DCI may be transmitted in a GC-DCI, which is described in more detail with reference to FIG. 3.

At 615, UE 115-b may generate precoded information based on the first stage uplink precoder indication and the second stage uplink precoder indication. UE 115-b may identify a payload size for a payload of the second stage uplink precoder indication, a fixed wideband co-phase indication granularity, a fixed subband co-phase indication granularity, and a number of subbands for frequency selective co-phase indication. UE 115-b may apply, sequentially or in parallel, a respective co-phase indication granularity criterion of a set of different co-phase indication granularity criteria to determine that a first co-phase indication granularity criterion of the set of different co-phase indication granularity criteria is satisfied, where the first co-phase indication granularity criterion corresponds to the payload interpretation rule. UE 115-b may determine that the payload satisfies a co-phase indication granularity criterion based on the payload size, the number of subbands, and one or both of the fixed wideband co-phase indication granularity and the fixed subband co-phase indication granularity. UE 115-b may apply a payload interpretation rule corresponding to the co-phase indication granularity criterion to interpret the payload of the second stage uplink precoder indication. Co-phase indication granularity and related criterion are described in more detail with reference to FIGs. 4 and 5.

At 620, UE 115-b may transmit a transmission generated based on the precoded information. The transmission may be in a PUSCH. In some implementations, the transmission may be a non-configured grant transmissions or a configured grant transmissions. At 625, base station 105-b may monitor for a signal generated (e.g., by UE 115-b) based on information precoded in accordance with the first stage uplink precoder indication and the second stage uplink precoder indication.

FIG. 7 shows a block diagram 700 of a device 705 that supports frequency selective uplink precoder indication in accordance with aspects of the present disclosure. The device 705 may be an example of aspects of a UE 115 as described herein. The device 705 may include a receiver 710, a communications manager 715, and a transmitter 720. The device 705 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .

The receiver 710 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to frequency selective uplink precoder indication) . Information may be passed on to other components of the device 705. The receiver 710 may be an example of aspects of the transceiver 1020 described with reference to FIG. 10. The receiver 710 may utilize a single antenna or a set of antennas.

The communications manager 715 may receive a first stage uplink precoder indication of wideband uplink precoding, receive a second stage uplink precoder indication of a first wideband co-phase granularity for the wideband uplink precoding, a subband co-phase granularity for subband uplink precoding, or both, each of the first wideband co-phase granularity and the subband co-phase granularity being finer than a second wideband co-phase granularity indicated by the first stage uplink precoder indication, generate precoded information based on the first stage uplink precoder indication and the second stage uplink precoder indication, and transmit a transmission generated based on the precoded information. The communications manager 715 may be an example of aspects of the communications manager 1010 described herein.

These operations of the communications manager 715 may provide some advantages for the device 705. For example, by using an uplink precoder with finer granularity, transmissions from the device 705 to a receiving device may have improved signal strength or signal quality. This may lead to higher throughput for the device 705, as the device may less frequently retransmit packets which were not successfully received or decoded by the receiving device.

In some examples, the operations of the communications manager 715 may also provide advantages for the components of the device 705. For example, by configuring multiple uplink precoder configurations with finer granularity in a first message and receiving an indication of a selected uplink precoder configuration in a second message, the components may have less overhead to parse in the second message, which may improve processing time for the components of the device 705. Additionally, by applying a more accurate (e.g., finer granularity) uplink precoder, the device 705 may less frequently make adjustments or updates to the uplink precoder, which may further reduce the amount of processing performed by components of the device 705.

The communications manager 715, or its sub-components, may be implemented in hardware, code (e.g., software or firmware) executed by a processor, or any combination thereof. If implemented in code executed by a processor, the functions of the communications manager 715, or its sub-components may be executed by a general-purpose processor, a digital signal processor (DSP) , an application-specific integrated circuit (ASIC) , a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure.

The communications manager 715, or its sub-components, may be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations by one or more physical components. In some examples, the communications manager 715, or its sub-components, may be a separate and distinct component in accordance with various aspects of the present disclosure. In some examples, the communications manager 715, or its sub-components, may be combined with one or more other hardware components, including but not limited to an input/output (I/O) component, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof in accordance with various aspects of the present disclosure.

The transmitter 720 may transmit signals generated by other components of the device 705. In some examples, the transmitter 720 may be collocated with a receiver 710 in a transceiver module. For example, the transmitter 720 may be an example of aspects of the transceiver 1020 described with reference to FIG. 10. The transmitter 720 may utilize a single antenna or a set of antennas.

FIG. 8 shows a block diagram 800 of a device 805 that supports frequency selective uplink precoder indication in accordance with aspects of the present disclosure. The device 805 may be an example of aspects of a device 705, or a UE 115 as described herein. The device 805 may include a receiver 810, a communications manager 815, and a transmitter 840. The device 805 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .

The receiver 810 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to frequency selective uplink precoder indication) . Information may be passed on to other components of the device 805. The receiver 810 may be an example of aspects of the transceiver 1020 described with reference to FIG. 10. The receiver 810 may utilize a single antenna or a set of antennas.

The communications manager 815 may be an example of aspects of the communications manager 715 as described herein. The communications manager 815 may include a first stage uplink precoder indication component 820, a second stage uplink precoder indication component 825, a precoded information generating component 830, and a precoded information transmitting component 835. The communications manager 815 may be an example of aspects of the communications manager 1010 described herein.

The first stage uplink precoder indication component 820 may receive a first stage uplink precoder indication of wideband uplink precoding. The second stage uplink precoder indication component 825 may receive a second stage uplink precoder indication of a first wideband co-phase granularity for the wideband uplink precoding, a subband co-phase granularity for subband uplink precoding, or both, each of the first wideband co-phase granularity and the subband co-phase granularity being finer than a second wideband co-phase granularity indicated by the first stage uplink precoder indication.

The precoded information generating component 830 may generate precoded information based on the first stage uplink precoder indication and the second stage uplink precoder indication. The precoded information transmitting component 835 may transmit a transmission generated based on the precoded information.

The transmitter 840 may transmit signals generated by other components of the device 805. In some examples, the transmitter 840 may be collocated with a receiver 810 in a transceiver module. For example, the transmitter 840 may be an example of aspects of the transceiver 1020 described with reference to FIG. 10. The transmitter 840 may utilize a single antenna or a set of antennas.

FIG. 9 shows a block diagram 900 of a communications manager 905 that supports frequency selective uplink precoder indication in accordance with aspects of the present disclosure. The communications manager 905 may be an example of aspects of a communications manager 715, a communications manager 815, or a communications manager 1010 described herein. The communications manager 905 may include a first stage uplink precoder indication component 910, a second stage uplink precoder indication component 915, a precoded information generating component 920, a precoded information transmitting component 925, a DCI receiving component 930, a GC-DCI component 935, and a payload interpretation component 940. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses) .

The first stage uplink precoder indication component 910 may receive a first stage uplink precoder indication of wideband uplink precoding. In some cases, the first stage uplink precoder indication is an uplink PMI.

The second stage uplink precoder indication component 915 may receive a second stage uplink precoder indication of a first wideband co-phase granularity for the wideband uplink precoding, a subband co-phase granularity for subband uplink precoding, or both, each of the first wideband co-phase granularity and the subband co-phase granularity being finer than a second wideband co-phase granularity indicated by the first stage uplink precoder indication.

In some examples, receiving control signaling that includes the first stage uplink precoder indication and the second stage uplink precoder indication. In some examples, receiving DCI that includes the first stage uplink precoder indication and the second stage uplink precoder indication. In some examples, receiving first DCI that includes the first stage uplink precoder indication and second DCI that includes the second stage uplink precoder indication.

In some examples, receiving an RRC configuration that includes the first stage uplink precoder indication and DCI that includes the second stage uplink precoder indication.

In some cases, the second stage uplink precoder indication indicates the first wideband co-phase granularity for at least one antenna port pair of a set of antenna ports, where the transmission is transmitted using the set of antenna ports. In some cases, the second stage uplink precoder indication indicates the subband co-phase granularity for at least one antenna port pair of a set of antenna ports, where the transmission is transmitted using the set of antenna ports.

The precoded information generating component 920 may generate precoded information based on the first stage uplink precoder indication and the second stage uplink precoder indication. The precoded information transmitting component 925 may transmit a transmission generated based on the precoded information. In some examples, the precoded information transmitting component 925 may identify a resource for transmitting the transmission. In some examples, the precoded information transmitting component 925 may receive control signaling that configures the UE with the resource for transmitting the transmission. In some examples, the precoded information transmitting component 925 may transmit the transmission in a PUSCH. In some cases, the transmission is a non-configured grant transmission or a configured grant transmission.

The DCI receiving component 930 may receive DCI that schedules the UE to transmit the transmission. In some cases, the DCI includes the first stage uplink precoder indication and the second stage uplink precoder indication. In some cases, the DCI includes the first stage uplink precoder indication and second DCI includes the second stage uplink precoder indication.

The GC-DCI component 935 may receive control signaling that configures the UE with a group temporary identifier and a search offset. In some examples, the GC-DCI component 935 may monitor a search space for the second stage uplink precoder indication based on the group temporary identifier and the search offset. In some examples, the GC-DCI component 935 may receive the control signaling that configures the UE with a set of different second stage uplink precoder configurations. In some examples, the GC-DCI component 935 may decode the search space to obtain DCI based on the group temporary identifier and the search offset.

In some examples, the GC-DCI component 935 may select a first configuration from the set of different second stage uplink precoder configurations based on the DCI, where the precoded information is generated based on the first configuration. In some examples, the GC-DCI component 935 may receive the control signaling that configures the UE with a set of different second stage uplink precoder configurations and a set of indexes respectively associated with the set of different second stage uplink precoder configurations. In some examples, the GC-DCI component 935 may decode the search space to obtain DCI and a first index of the set of indexes based on the group temporary identifier and the search offset. In some examples, the GC-DCI component 935 may select a first configuration from the set of different second stage uplink precoder configurations based on the DCI and the first index, where the precoded information is generated based on the first configuration.

The payload interpretation component 940 may identify a payload size for a payload of the second stage uplink precoder indication, a minimum wideband co-phase indication granularity, a minimum subband co-phase indication granularity, and a number of subbands for frequency selective co-phase indication. In some examples, the payload interpretation component 940 may determine that the payload satisfies a co-phase indication granularity criterion based on the payload size, the number of subbands, and one or both of the minimum wideband co-phase indication granularity and the minimum subband co-phase indication granularity.

In some examples, the payload interpretation component 940 may apply a payload interpretation rule corresponding to the co-phase indication granularity criterion to interpret the payload of the second stage uplink precoder indication. In some examples, the payload interpretation component 940 may apply, sequentially or in parallel, a respective co-phase indication granularity criterion of a set of different co-phase indication granularity criteria to determine that a first co-phase indication granularity criterion of the set of different co-phase indication granularity criteria is satisfied, where the first co-phase indication granularity criterion corresponds to the payload interpretation rule.

In some examples, the payload interpretation component 940 may receive an RRC configuration, DCI, or both, including one or more of the payload size for the payload of the second stage uplink precoder indication, the minimum wideband co-phase indication granularity, the minimum subband co-phase indication granularity, and the number of subbands for frequency selective co-phase indication. In some examples, the payload interpretation component 940 may identify a set of parameters including one or more of the payload size for the payload of the second stage uplink precoder indication, the minimum wideband co-phase indication granularity, the minimum subband co-phase indication granularity, and the number of subbands for frequency selective co-phase indication, where the identifying is based on at least one predefinition for one or more parameters of the set of parameters stored in a storage device of the UE, receiving an RRC configuration indicating one or more parameters of the set of parameters, receiving DCI indicating one or more parameters of the set of parameters, or any combination thereof. In some examples, the payload interpretation component 940 may receive the control signaling that configures the UE with a set of different second stage uplink precoder configurations and a set of indexes respectively associated with the set of different second stage uplink precoder configurations.

In some examples, the payload interpretation component 940 may decode the search space to obtain DCI and a first index of the set of indexes based on the group temporary identifier and the search offset. In some examples, the payload interpretation component 940 may select a first configuration from the set of different second stage uplink precoder configurations based on the DCI and the first index, where the payload of the second stage uplink precoder indication corresponds to the first configuration.

In some examples, the payload interpretation component 940 may identify a payload size for a payload of the second stage uplink precoder indication, a fixed wideband co-phase indication granularity, a fixed subband co-phase indication granularity, and a number of subbands for frequency selective co-phase indication. In some examples, the payload interpretation component 940 may determine that the payload satisfies a co-phase indication granularity criterion based on the payload size, the number of subbands, and one or both of the fixed wideband co-phase indication granularity and the fixed subband co-phase indication granularity.

In some examples, the payload interpretation component 940 may receive an RRC configuration, DCI, or both, including one or more of the payload size for the payload of the second stage uplink precoder indication, the fixed wideband co-phase indication granularity, the fixed subband co-phase indication granularity, and the number of subbands for frequency selective co-phase indication. In some examples, the payload interpretation component 940 may identify a set of parameters including one or more of the payload size for the payload of the second stage uplink precoder indication, the fixed wideband co-phase indication granularity, the fixed subband co-phase indication granularity, and the number of subbands for frequency selective co-phase indication, where the identifying is based on at least one predefinition for one or more parameters of the set of parameters stored in a storage device of the UE, receiving an RRC configuration indicating one or more parameters of the set of parameters, receiving DCI indicating one or more parameters of the set of parameters, or any combination thereof.

In some examples, the payload interpretation component 940 may where the payload interpretation rule is that a first bit subset of the payload indicates a wideband co-phase that satisfies the fixed wideband co-phase indication granularity, that a second bit subset of the payload indicates an adaptive subband selection rule, and that, for at least one subband of the set of subbands indicated in the adaptive subband selection rule, a third bit subset of the payload provides a differential subband co-phase indication relative to the wideband co-phase that satisfies the fixed subband co-phase indication granularity.

In some examples, the payload interpretation component 940 may adaptive subband selection rule indicates to interpret the payload as selecting, starting from a nth subband of the set of subbands, every (K+n) th, (2K+n) th, (3K+n) th subband, where K is selected so that the third bit subset provides differential subband co-phase indication that satisfies the fixed subband co-phase indication granularity, and n is preconfigured or RRC configured.

In some cases, the co-phase indication granularity criterion is that, using bits of the payload, the subband co-phase granularity at least satisfies the minimum subband co-phase indication granularity for each subband of a set of subbands, and where the payload interpretation rule is that the subband co-phase granularity for each subband of the set of subbands is indicated using respective bit subsets of the payload each having an equal number of bits that indicate a subband specific co-phase with equal co-phase granularity for each of the set of subbands. In some examples, the payload interpretation rule is that a first bit subset of the payload indicates a wideband co-phase that satisfies the minimum wideband co-phase indication granularity and that the subband co-phase granularity for each subband of a set of subbands is differentially indicated relative to the wideband co-phase using respective bit subsets in a remainder of the payload, the subband co-phase granularity for each subband of the set of subbands having equal co-phase granularity.

In some cases, the co-phase indication granularity criterion is that, using bits of the payload, the subband co-phase granularity does not satisfy the minimum subband co-phase indication granularity, that, using the bits of the payload, the first wideband co-phase granularity at least satisfies the minimum wideband co-phase indication granularity, and that, apart from a subset of the bits of the payload used for indicating the first wideband co-phase granularity, remaining bits of the payload are capable of subband differential co-phase indication that satisfies the minimum subband co-phase indication granularity. In some examples, the payload interpretation rule is that a first bit subset of the payload indicates a wideband co-phase that satisfies the minimum wideband co-phase indication granularity.

In some cases, the co-phase indication granularity criterion is that, using bits of the payload, the first wideband co-phase granularity at least satisfies the minimum wideband co-phase indication granularity and that, apart from a subset of the bits of the payload used for indicating the first wideband co-phase granularity, remaining bits of the payload are not capable of subband differential co-phase indication that satisfies the minimum subband co-phase indication granularity. In some examples, the payload interpretation rule is that bits of the payload indicate a wideband co-phase for each antenna port pair that has a finer wideband co-phase granularity than the minimum wideband co-phase indication granularity.

In some cases, the finer wideband co-phase granularity maximizes wideband co-phase granularity corresponding to the payload size. In some cases, the co-phase indication granularity criterion is that, using bits of the payload, the subband co-phase granularity satisfies the fixed subband co-phase indication granularity, and where the payload interpretation rule is that the subband co-phase granularity for each subband of a set of subbands is indicated using a same number of bits of the payload to indicate subband specific co-phase that satisfies the fixed subband co-phase indication granularity. In some examples, the payload interpretation rule is that a first bit subset of the payload indicates a wideband co-phase that satisfies the fixed wideband co-phase indication granularity and that the subband co-phase granularity for each subband of a set of subbands is differentially indicated relative to the wideband co-phase using respective bit subsets of the remaining bits of the payload, the subband co-phase granularity for each subband of the set of subbands satisfying the fixed subband co-phase indication granularity.

In some cases, the co-phase indication granularity criterion is that, using bits of the payload, the subband co-phase granularity does not satisfy the fixed subband co-phase indication granularity, that, using the bits of the payload, the first wideband co-phase granularity satisfies the fixed wideband co-phase indication granularity, and that, apart from a subset of the bits of the payload used for indicating the first wideband co-phase granularity, remaining bits of the payload are capable of subband differential co-phase indication that satisfies the fixed subband co-phase indication granularity. In some examples, the payload interpretation rule is that a first bit subset of the payload indicates a wideband co-phase that satisfies the fixed wideband co-phase indication granularity, that a second bit subset of the payload indicates a subband index bitmap, and that, for at least one subband indicated in the subband index bitmap, a third subset of the payload provides a differential subband co-phase indication relative to the wideband co-phase that satisfies the fixed subband co-phase indication granularity.

In some cases, the co-phase indication granularity criterion is that, using bits of the payload, the first wideband co-phase granularity at least satisfies the fixed wideband co-phase indication granularity and that, apart from a subset of the bits of the payload used for indicating the first wideband co-phase granularity, remaining bits of the payload are not capable of satisfying the fixed subband co-phase indication granularity for each subband of a set of subbands. In some examples, the payload interpretation rule is that a first bit subset of the payload indicates a wideband co-phase that satisfies the fixed wideband co-phase indication granularity, that a second bit subset of the payload indicates a subband selection pattern, and that, for at least one subband indicated in the subband selection pattern, a third bit subset of the payload provides a differential subband co-phase indication relative to the wideband co-phase that satisfies the fixed subband co-phase indication granularity.

In some cases, the bitmap indicates positive and negative subband indexes from the set of subbands, where a first subband subset of the set of subbands with positive indexes are indicated with subband co-phases and a second subband subset of the set of subbands with negative indexes are not indicated with subband co-phases.

In some cases, the subband co-phase granularity for the first subband subset of the set of subbands with positive indexes satisfies the fixed subband co-phase indication granularity. In some cases, the second bit subset is a combinatorial number that indicates the subband selection pattern from among a set of candidate subband selection patterns. In some cases, the subband co-phase granularity for the at least one subband indicated in the subband selection pattern indicted satisfies the fixed subband co-phase indication granularity.

FIG. 10 shows a diagram of a system 1000 including a device 1005 that supports frequency selective uplink precoder indication in accordance with aspects of the present disclosure. The device 1005 may be an example of or include the components of device 705, device 805, or a UE 115 as described herein. The device 1005 may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including a communications manager 1010, an I/O controller 1015, a transceiver 1020, an antenna 1025, memory 1030, and a processor 1040. These components may be in electronic communication via one or more buses (e.g., bus 1045) .

The communications manager 1010 may receive a first stage uplink precoder indication of wideband uplink precoding, receive a second stage uplink precoder indication of a first wideband co-phase granularity for the wideband uplink precoding, a subband co-phase granularity for subband uplink precoding, or both, each of the first wideband co-phase granularity and the subband co-phase granularity being finer than a second wideband co-phase granularity indicated by the first stage uplink precoder indication, generate precoded information based on the first stage uplink precoder indication and the second stage uplink precoder indication, and transmit a transmission generated based on the precoded information.

The I/O controller 1015 may manage input and output signals for the device 1005. The I/O controller 1015 may also manage peripherals not integrated into the device 1005. In some cases, the I/O controller 1015 may represent a physical connection or port to an external peripheral. In some cases, the I/O controller 1015 may utilize an operating system such as

or another known operating system. In other cases, the I/O controller 1015 may represent or interact with a modem, a keyboard, a mouse, a touchscreen, or a similar device. In some cases, the I/O controller 1015 may be implemented as part of a processor. In some cases, a user may interact with the device 1005 via the I/O controller 1015 or via hardware components controlled by the I/O controller 1015.

The transceiver 1020 may communicate bi-directionally, via one or more antennas, wired, or wireless links as described above. For example, the transceiver 1020 may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver 1020 may also include a modem to modulate the packets and provide the modulated packets to the antennas for transmission, and to demodulate packets received from the antennas.

In some cases, the wireless device may include a single antenna 1025. However, in some cases the device may have more than one antenna 1025, which may be capable of concurrently transmitting or receiving multiple wireless transmissions.

The memory 1030 may include random-access memory (RAM) and read-only memory (ROM) . The memory 1030 may store computer-readable, computer-executable code 1035 including instructions that, when executed, cause the processor to perform various functions described herein. In some cases, the memory 1030 may contain, among other things, a basic input/output system (BIOS) which may control basic hardware or software operation such as the interaction with peripheral components or devices.

The processor 1040 may include an intelligent hardware device, (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof) . In some cases, the processor 1040 may be configured to operate a memory array using a memory controller. In other cases, a memory controller may be integrated into the processor 1040. The processor 1040 may be configured to execute computer-readable instructions stored in a memory (e.g., the memory 1030) to cause the device 1005 to perform various functions (e.g., functions or tasks supporting frequency selective uplink precoder indication) .

The code 1035 may include instructions to implement aspects of the present disclosure, including instructions to support wireless communications. The code 1035 may be stored in a non-transitory computer-readable medium such as system memory or other type of memory. In some cases, the code 1035 may not be directly executable by the processor 1040 but may cause a computer (e.g., when compiled and executed) to perform functions described herein.

FIG. 11 shows a block diagram 1100 of a device 1105 that supports frequency selective uplink precoder indication in accordance with aspects of the present disclosure. The device 1105 may be an example of aspects of a base station 105 as described herein. The device 1105 may include a receiver 1110, a communications manager 1115, and a transmitter 1120. The device 1105 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .

The receiver 1110 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to frequency selective uplink precoder indication) . Information may be passed on to other components of the device 1105. The receiver 1110 may be an example of aspects of the transceiver 1420 described with reference to FIG. 14. The receiver 1110 may utilize a single antenna or a set of antennas.

The communications manager 1115 may transmit a first stage uplink precoder indication of wideband precoding, transmit a second stage uplink precoder indication of a first wideband co-phase granularity for the wideband precoding, a subband co-phase granularity for subband uplink precoding, or both, each of the first wideband co-phase granularity and the subband co-phase granularity being finer than a second wideband co-phase granularity indicated by the first stage uplink precoder indication, and monitor for a signal generated based on information precoded in accordance with the first stage uplink precoder indication and the second stage uplink precoder indication. The communications manager 1115 may be an example of aspects of the communications manager 1410 described herein.

The communications manager 1115, or its sub-components, may be implemented in hardware, code (e.g., software or firmware) executed by a processor, or any combination thereof. If implemented in code executed by a processor, the functions of the communications manager 1115, or its sub-components may be executed by a general-purpose processor, a DSP, an ASIC, a FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure.

The communications manager 1115, or its sub-components, may be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations by one or more physical components. In some examples, the communications manager 1115, or its sub-components, may be a separate and distinct component in accordance with various aspects of the present disclosure. In some examples, the communications manager 1115, or its sub-components, may be combined with one or more other hardware components, including but not limited to an input/output (I/O) component, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof in accordance with various aspects of the present disclosure.

The transmitter 1120 may transmit signals generated by other components of the device 1105. In some examples, the transmitter 1120 may be collocated with a receiver 1110 in a transceiver module. For example, the transmitter 1120 may be an example of aspects of the transceiver 1420 described with reference to FIG. 14. The transmitter 1120 may utilize a single antenna or a set of antennas.

FIG. 12 shows a block diagram 1200 of a device 1205 that supports frequency selective uplink precoder indication in accordance with aspects of the present disclosure. The device 1205 may be an example of aspects of a device 1105, or a base station 105 as described herein. The device 1205 may include a receiver 1210, a communications manager 1215, and a transmitter 1235. The device 1205 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .

The receiver 1210 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to frequency selective uplink precoder indication) . Information may be passed on to other components of the device 1205. The receiver 1210 may be an example of aspects of the transceiver 1420 described with reference to FIG. 14. The receiver 1210 may utilize a single antenna or a set of antennas.

The communications manager 1215 may be an example of aspects of the communications manager 1115 as described herein. The communications manager 1215 may include a first stage uplink precoder indication component 1220, a second stage uplink precoder indication component 1225, and a precoded information monitoring component 1230. The communications manager 1215 may be an example of aspects of the communications manager 1410 described herein.

The first stage uplink precoder indication component 1220 may transmit a first stage uplink precoder indication of wideband precoding. The second stage uplink precoder indication component 1225 may transmit a second stage uplink precoder indication of a first wideband co-phase granularity for the wideband precoding, a subband co-phase granularity for subband uplink precoding, or both, each of the first wideband co-phase granularity and the subband co-phase granularity being finer than a second wideband co-phase granularity indicated by the first stage uplink precoder indication.

The precoded information monitoring component 1230 may monitor for a signal generated based on information precoded in accordance with the first stage uplink precoder indication and the second stage uplink precoder indication.

The transmitter 1235 may transmit signals generated by other components of the device 1205. In some examples, the transmitter 1235 may be collocated with a receiver 1210 in a transceiver module. For example, the transmitter 1235 may be an example of aspects of the transceiver 1420 described with reference to FIG. 14. The transmitter 1235 may utilize a single antenna or a set of antennas.

FIG. 13 shows a block diagram 1300 of a communications manager 1305 that supports frequency selective uplink precoder indication in accordance with aspects of the present disclosure. The communications manager 1305 may be an example of aspects of a communications manager 1115, a communications manager 1215, or a communications manager 1410 described herein. The communications manager 1305 may include a first stage uplink precoder indication component 1310, a second stage uplink precoder indication component 1315, a precoded information monitoring component 1320, a GC-DCI component 1325, and a payload generating component 1330. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses) .

The first stage uplink precoder indication component 1310 may transmit a first stage uplink precoder indication of wideband precoding. In some cases, the first stage uplink precoder indication is a PMI. In some cases, the first stage uplink precoder indication is an uplink PMI.

The second stage uplink precoder indication component 1315 may transmit a second stage uplink precoder indication of a first wideband co-phase granularity for the wideband precoding, a subband co-phase granularity for subband uplink precoding, or both, each of the first wideband co-phase granularity and the subband co-phase granularity being finer than a second wideband co-phase granularity indicated by the first stage uplink precoder indication.

In some examples, transmitting control signaling that includes the first stage uplink precoder indication and the second stage uplink precoder indication. In some examples, transmitting DCI that includes the first stage uplink precoder indication and the second stage uplink precoder indication. In some examples, transmitting an RRC configuration that includes the first stage uplink precoder indication and DCI that includes the second stage uplink precoder indication.

In some examples, the second stage uplink precoder indication component 1315 may transmit the control signaling that configures the UE with a set of different second stage uplink precoder configurations and a set of indexes respectively associated with the set of different second stage uplink precoder configurations. In some cases, the second stage uplink precoder indication indicates the wideband co-phase granularity for at least one antenna port pair of a set of antenna ports. In some cases, the second stage uplink precoder indication indicates the subband co-phase granularity for at least one antenna port pair of a set of antenna ports.

The precoded information monitoring component 1320 may monitor for a signal generated based on information precoded in accordance with the first stage uplink precoder indication and the second stage uplink precoder indication. In some examples, the precoded information monitoring component 1320 may transmit control signaling that configures a UE with a resource for transmitting the signal. In some examples, the precoded information monitoring component 1320 may transmit DCI that schedules the UE to transmit the signal. In some examples, the precoded information monitoring component 1320 may receive the signal in a PUSCH. In some cases, the DCI includes the second stage uplink precoder indication. In some cases, the DCI includes the first stage uplink precoder indication. In some cases, the signal is a non-configured grant transmission or a configured grant transmission.

The GC-DCI component 1325 may transmit control signaling that configures a UE with a group temporary identifier and a search offset. In some examples, the GC-DCI component 1325 may transmit the control signaling that configures the UE with a set of different second stage uplink precoder configurations. In some examples, the GC-DCI component 1325 may transmit the control signaling that configures the UE with a set of different second stage uplink precoder configurations and a set of indexes respectively associated with the set of different second stage uplink precoder configurations.

The payload generating component 1330 may identify a payload size for a payload of the second stage uplink precoder indication, a minimum wideband co-phase indication granularity, a minimum subband co-phase indication granularity, and a number of subbands for frequency selective co-phase indication. In some examples, the payload generating component 1330 may determine that the payload satisfies a co-phase indication granularity criterion based on the payload size, the number of subbands, and one or both of the minimum wideband co-phase indication granularity and the minimum subband co-phase indication granularity.

In some examples, the payload generating component 1330 may generate the payload of the second stage uplink precoder indication in accordance with a payload interpretation rule corresponding to the co-phase indication granularity criterion. In some examples, the payload generating component 1330 may apply, sequentially or in parallel, a respective co-phase indication granularity criterion of a set of different co-phase indication granularity criteria to determine that a first co-phase indication granularity criterion of the set of different co-phase indication granularity criteria is satisfied, where the first co-phase indication granularity criterion corresponds to the payload interpretation rule.

In some examples, the payload generating component 1330 may transmit an RRC configuration, DCI, or both, including one or more of the payload size for the payload of the second stage uplink precoder indication, the minimum wideband co-phase indication granularity, the minimum subband co-phase indication granularity, and the number of subbands for frequency selective co-phase indication. In some examples, the payload generating component 1330 may identify a set of parameters including one or more of the payload size for the payload of the second stage uplink precoder indication, the minimum wideband co-phase indication granularity, the minimum subband co-phase indication granularity, and the number of subbands for frequency selective co-phase indication based on at least one predefinition for one or more parameters of the set of parameters, a RRC configuration indicating one or more parameters of the set of parameters, DCI indicating one or more parameters of the set of parameters, or any combination thereof.

In some examples, the payload generating component 1330 may identify a payload size for a payload of the second stage uplink precoder indication, a fixed wideband co-phase indication granularity, a fixed subband co-phase indication granularity, and a number of subbands for frequency selective co-phase indication.

In some examples, the payload generating component 1330 may determine that the payload satisfies a co-phase indication granularity criterion based on the payload size, the number of subbands, and one or both of the fixed wideband co-phase indication granularity and the fixed subband co-phase indication granularity. In some examples, the payload generating component 1330 may transmit an RRC configuration, DCI, or both, including one or more of the payload size for the payload of the second stage uplink precoder indication, the fixed wideband co-phase indication granularity, the fixed subband co-phase indication granularity, and the number of subbands for frequency selective co-phase indication. In some examples, the payload generating component 1330 may identify a set of parameters including one or more of the payload size for the payload of the second stage uplink precoder indication, the fixed wideband co-phase indication granularity, the fixed subband co-phase indication granularity, and the number of subbands for frequency selective co-phase indication, where the identifying is based on at least one predefinition for one or more parameters of the set of parameters, a RRC configuration indicating one or more parameters of the set of parameters, DCI indicating one or more parameters of the set of parameters, or any combination thereof.

In some examples, the payload generating component 1330 may adaptive subband selection rule indicates to interpret the payload as selecting, starting from a nth subband of the set of subbands, every (K+n) th, (2K+n) th, (3K+n) th subband, where K is selected so that the third bit subset provides differential subband co-phase indication that satisfies the fixed subband co-phase indication granularity, and n is preconfigured or RRC configured.

In some cases, the co-phase indication granularity criterion is that, using bits of the payload, the subband co-phase granularity does not satisfy the minimum subband co-phase indication granularity, that, using the bits of the payload, the first wideband co-phase granularity at least satisfies the minimum wideband co-phase indication granularity, and that, apart from a subset of the bits of the payload used for indicating the first wideband co-phase granularity, remaining bits of the payload are capable of subband differential co-phase indication that satisfies the minimum subband co-phase indication granularity. In some examples, the payload interpretation rule is that bits of the payload indicate a wideband co-phase for each antenna port pair that has a finer wideband co-phase granularity than the minimum wideband co-phase indication granularity.

In some cases, the co-phase indication granularity criterion is that, using bits of the payload, the first wideband co-phase granularity at least satisfies the minimum wideband co-phase indication granularity and that, apart from a subset of the bits of the payload used for indicating the first wideband co-phase granularity, remaining bits of the payload are not capable of subband differential co-phase indication that satisfies the minimum subband co-phase indication granularity, and where the payload interpretation rule is that a first bit subset of the payload indicates a wideband co-phase that satisfies the minimum wideband co-phase indication granularity. In some examples, the payload interpretation rule is that a first bit subset of the payload indicates a wideband co-phase that satisfies the fixed wideband co-phase indication granularity and that the subband co-phase granularity for each subband of a set of subbands is differentially indicated relative to the wideband co-phase using respective bit subsets of the remaining bits of the payload, the subband co-phase granularity for each subband of the set of subbands satisfying the fixed subband co-phase indication granularity.

In some cases, the co-phase indication granularity criterion is that, using bits of the payload, the first wideband co-phase granularity at least satisfies the minimum wideband co-phase indication granularity and that, apart from a subset of the bits of the payload used for indicating the first wideband co-phase granularity, remaining bits of the payload are not capable of subband differential co-phase indication that satisfies the minimum subband co-phase indication granularity. In some examples, the payload interpretation rule is that a first bit subset of the payload indicates a wideband co-phase that satisfies the fixed wideband co-phase indication granularity, that a second bit subset of the payload indicates a subband index bitmap, and that, for at least one subband indicated in the subband index bitmap, a third subset of the payload provides a differential subband co-phase indication relative to the wideband co-phase that satisfies the fixed subband co-phase indication granularity.

In some cases, the finer wideband co-phase granularity maximizes wideband co-phase granularity corresponding to the payload size.

In some cases, the co-phase indication granularity criterion is that, using bits of the payload, the subband co-phase granularity satisfies the fixed subband co-phase indication granularity, and where the payload interpretation rule is that the subband co-phase granularity for each subband of a set of subbands is indicated using a same number of bits of the payload to indicate subband specific co-phase that satisfies the fixed subband co-phase indication granularity.

In some cases, the co-phase indication granularity criterion is that, using bits of the payload, the subband co-phase granularity does not satisfy the fixed subband co-phase indication granularity, that, using the bits of the payload, the first wideband co-phase granularity satisfies the fixed wideband co-phase indication granularity, and that, apart from a subset of the bits of the payload used for indicating the first wideband co-phase granularity, remaining bits of the payload are capable of subband differential co-phase indication that satisfies the fixed subband co-phase indication granularity. In some examples, the payload interpretation rule is that a first bit subset of the payload indicates a wideband co-phase that satisfies the fixed wideband co-phase indication granularity, that a second bit subset of the payload indicates a subband selection pattern, and that, for at least one subband indicated in the subband selection pattern, a third bit subset of the payload provides a differential subband co-phase indication relative to the wideband co-phase that satisfies the fixed subband co-phase indication granularity.

In some cases, the co-phase indication granularity criterion is that, using bits of the payload, the first wideband co-phase granularity at least satisfies the fixed wideband co-phase indication granularity and that, apart from a subset of the bits of the payload used for indicating the first wideband co-phase granularity, remaining bits of the payload are not capable of satisfying the fixed subband co-phase indication granularity for each subband of a set of subbands. In some examples, the payload interpretation rule is that a first bit subset of the payload indicates a wideband co-phase that satisfies the fixed wideband co-phase indication granularity, that a second bit subset of the payload indicates an adaptive subband selection rule, and that, for at least one subband of the set of subbands indicated in the adaptive subband selection rule, a third bit subset of the payload provides a differential subband co-phase indication relative to the wideband co-phase that satisfies the fixed subband co-phase indication granularity.

In some cases, the subband index bitmap indicates positive and negative subband indexes from the set of subbands, where a first subband subset of the set of subbands with positive indexes are indicated with subband co-phases and a second subband subset of the set of subbands with negative indexes are not indicated with subband co-phases.

FIG. 14 shows a diagram of a system 1400 including a device 1405 that supports frequency selective uplink precoder indication in accordance with aspects of the present disclosure. The device 1405 may be an example of or include the components of device 1105, device 1205, or a base station 105 as described herein. The device 1405 may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including a communications manager 1410, a network communications manager 1415, a transceiver 1420, an antenna 1425, memory 1430, a processor 1440, and an inter-station communications manager 1445. These components may be in electronic communication via one or more buses (e.g., bus 1450) .

The communications manager 1410 may transmit a first stage uplink precoder indication of wideband precoding, transmit a second stage uplink precoder indication of a first wideband co-phase granularity for the wideband precoding, a subband co-phase granularity for subband uplink precoding, or both, each of the first wideband co-phase granularity and the subband co-phase granularity being finer than a second wideband co-phase granularity indicated by the first stage uplink precoder indication, and monitor for a signal generated based on information precoded in accordance with the first stage uplink precoder indication and the second stage uplink precoder indication.

The network communications manager 1415 may manage communications with the core network (e.g., via one or more wired backhaul links) . For example, the network communications manager 1415 may manage the transfer of data communications for client devices, such as one or more UEs 115.

The transceiver 1420 may communicate bi-directionally, via one or more antennas, wired, or wireless links as described above. For example, the transceiver 1420 may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver 1420 may also include a modem to modulate the packets and provide the modulated packets to the antennas for transmission, and to demodulate packets received from the antennas.

In some cases, the wireless device may include a single antenna 1425. However, in some cases the device may have more than one antenna 1425, which may be capable of concurrently transmitting or receiving multiple wireless transmissions.

The memory 1430 may include RAM, ROM, or a combination thereof. The memory 1430 may store computer-readable code 1435 including instructions that, when executed by a processor (e.g., the processor 1440) cause the device to perform various functions described herein. In some cases, the memory 1430 may contain, among other things, a BIOS which may control basic hardware or software operation such as the interaction with peripheral components or devices.

The processor 1440 may include an intelligent hardware device, (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof) . In some cases, the processor 1440 may be configured to operate a memory array using a memory controller. In some cases, a memory controller may be integrated into processor 1440. The processor 1440 may be configured to execute computer- readable instructions stored in a memory (e.g., the memory 1430) to cause the device 1405 to perform various functions (e.g., functions or tasks supporting frequency selective uplink precoder indication) .

The inter-station communications manager 1445 may manage communications with other base station 105, and may include a controller or scheduler for controlling communications with UEs 115 in cooperation with other base stations 105. For example, the inter-station communications manager 1445 may coordinate scheduling for transmissions to UEs 115 for various interference mitigation techniques such as beamforming or joint transmission. In some examples, the inter-station communications manager 1445 may provide an X2 interface within an LTE/LTE-A wireless communication network technology to provide communication between base stations 105.

The code 1435 may include instructions to implement aspects of the present disclosure, including instructions to support wireless communications. The code 1435 may be stored in a non-transitory computer-readable medium such as system memory or other type of memory. In some cases, the code 1435 may not be directly executable by the processor 1440 but may cause a computer (e.g., when compiled and executed) to perform functions described herein.

FIG. 15 shows a flowchart illustrating a method 1500 that supports frequency selective uplink precoder indication in accordance with aspects of the present disclosure. The operations of method 1500 may be implemented by a UE 115 or its components as described herein. For example, the operations of method 1500 may be performed by a communications manager as described with reference to FIGs. 7 through 10. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware.

At 1505, the UE may receive a first stage uplink precoder indication of wideband uplink precoding. The operations of 1505 may be performed according to the methods described herein. In some examples, aspects of the operations of 1505 may be performed by a first stage uplink precoder indication component as described with reference to FIGs. 7 through 10.

At 1510, the UE may receive a second stage uplink precoder indication of a first wideband co-phase granularity for the wideband uplink precoding, a subband co-phase granularity for subband uplink precoding, or both, each of the first wideband co-phase granularity and the subband co-phase granularity being finer than a second wideband co-phase granularity indicated by the first stage uplink precoder indication. The operations of 1510 may be performed according to the methods described herein. In some examples, aspects of the operations of 1510 may be performed by a second stage uplink precoder indication component as described with reference to FIGs. 7 through 10.

At 1515, the UE may generate precoded information based on the first stage uplink precoder indication and the second stage uplink precoder indication. The operations of 1515 may be performed according to the methods described herein. In some examples, aspects of the operations of 1515 may be performed by a precoded information generating component as described with reference to FIGs. 7 through 10.

At 1520, the UE may transmit a transmission generated based on the precoded information. The operations of 1520 may be performed according to the methods described herein. In some examples, aspects of the operations of 1520 may be performed by a precoded information transmitting component as described with reference to FIGs. 7 through 10.

These techniques described herein may provide some advantages for a UE 115 and a base station 105. For example, by using an uplink precoder with finer granularity, transmissions from the UE 115 to the base station 105 may have improved signal strength or signal quality. This may lead to higher uplink throughput for the UE 115 and base station 105, as the UE 115 may less frequently retransmit packets which were not successfully received or decoded by the base station 105.

In some examples, the techniques may also provide advantages for the components of the UE 115 and base station 105. For example, by configuring multiple uplink precoder configurations with finer granularity in a first message and receiving an indication of a selected uplink precoder configuration in a second message, the components of the UE 115 may have less overhead to parse in the second message, which may improve processing time for the components of the UE 115. The base station 105 may similarly have less overhead when generating a DCI payload. Additionally, by applying a more accurate (e.g., finer granularity) uplink precoder, the UE 115 may less frequently make adjustments or updates to the uplink precoder, which may further reduce the amount of processing performed by components of the UE 115.

FIG. 16 shows a flowchart illustrating a method 1600 that supports frequency selective uplink precoder indication in accordance with aspects of the present disclosure. The operations of method 1600 may be implemented by a UE 115 or its components as described herein. For example, the operations of method 1600 may be performed by a communications manager as described with reference to FIGs. 7 through 10. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware.

At 1605, the UE may receive control signaling that includes the first stage uplink precoder indication and the second stage uplink precoder indication. The operations of 1605 may be performed according to the methods described herein. In some examples, aspects of the operations of 1605 may be performed by a second stage uplink precoder indication component as described with reference to FIGs. 7 through 10.

At 1610, the UE may identify a resource for transmitting the transmission. The operations of 1610 may be performed according to the methods described herein. In some examples, aspects of the operations of 1610 may be performed by a precoded information transmitting component as described with reference to FIGs. 7 through 10.

At 1615, the UE may receive a first stage uplink precoder indication of wideband uplink precoding. The operations of 1615 may be performed according to the methods described herein. In some examples, aspects of the operations of 1615 may be performed by a first stage uplink precoder indication component as described with reference to FIGs. 7 through 10.

At 1620, the UE may receive a second stage uplink precoder indication of a first wideband co-phase granularity for the wideband uplink precoding, a subband co-phase granularity for subband uplink precoding, or both, each of the first wideband co-phase granularity and the subband co-phase granularity being finer than a second wideband co-phase granularity indicated by the first stage uplink precoder indication. The operations of 1620 may be performed according to the methods described herein. In some examples, aspects of the operations of 1620 may be performed by a second stage uplink precoder indication component as described with reference to FIGs. 7 through 10.

At 1625, the UE may generate precoded information based on the first stage uplink precoder indication and the second stage uplink precoder indication. The operations of 1625 may be performed according to the methods described herein. In some examples, aspects of the operations of 1625 may be performed by a precoded information generating component as described with reference to FIGs. 7 through 10.

At 1630, the UE may transmit a transmission generated based on the precoded information. The operations of 1630 may be performed according to the methods described herein. In some examples, aspects of the operations of 1630 may be performed by a precoded information transmitting component as described with reference to FIGs. 7 through 10.

FIG. 17 shows a flowchart illustrating a method 1700 that supports frequency selective uplink precoder indication in accordance with aspects of the present disclosure. The operations of method 1700 may be implemented by a UE 115 or its components as described herein. For example, the operations of method 1700 may be performed by a communications manager as described with reference to FIGs. 7 through 10. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware.

At 1705, the UE may receive control signaling that configures the UE with a group temporary identifier and a search offset. The operations of 1705 may be performed according to the methods described herein. In some examples, aspects of the operations of 1705 may be performed by a GC-DCI component as described with reference to FIGs. 7 through 10.

At 1710, the UE may monitor a search space for the second stage uplink precoder indication based on the group temporary identifier and the search offset. The operations of 1710 may be performed according to the methods described herein. In some examples, aspects of the operations of 1710 may be performed by a GC-DCI component as described with reference to FIGs. 7 through 10.

At 1715, the UE may receive a first stage uplink precoder indication of wideband uplink precoding. The operations of 1715 may be performed according to the methods described herein. In some examples, aspects of the operations of 1715 may be performed by a first stage uplink precoder indication component as described with reference to FIGs. 7 through 10.

At 1720, the UE may receive a second stage uplink precoder indication of a first wideband co-phase granularity for the wideband uplink precoding, a subband co-phase granularity for subband uplink precoding, or both, each of the first wideband co-phase granularity and the subband co-phase granularity being finer than a second wideband co-phase granularity indicated by the first stage uplink precoder indication. The operations of 1720 may be performed according to the methods described herein. In some examples, aspects of the operations of 1720 may be performed by a second stage uplink precoder indication component as described with reference to FIGs. 7 through 10.

At 1725, the UE may generate precoded information based on the first stage uplink precoder indication and the second stage uplink precoder indication. The operations of 1725 may be performed according to the methods described herein. In some examples, aspects of the operations of 1725 may be performed by a precoded information generating component as described with reference to FIGs. 7 through 10.

At 1730, the UE may transmit a transmission generated based on the precoded information. The operations of 1730 may be performed according to the methods described herein. In some examples, aspects of the operations of 1730 may be performed by a precoded information transmitting component as described with reference to FIGs. 7 through 10.

At 1735, the UE may receive the control signaling that configures the UE with a set of different second stage uplink precoder configurations. The operations of 1735 may be performed according to the methods described herein. In some examples, aspects of the operations of 1735 may be performed by a GC-DCI component as described with reference to FIGs. 7 through 10.

At 1740, the UE may decode the search space to obtain DCI based on the group temporary identifier and the search offset. The operations of 1740 may be performed according to the methods described herein. In some examples, aspects of the operations of 1740 may be performed by a GC-DCI component as described with reference to FIGs. 7 through 10.

At 1745, the UE may select a first configuration from the set of different second stage uplink precoder configurations based on the DCI, where the precoded information is generated based on the first configuration. The operations of 1745 may be performed according to the methods described herein. In some examples, aspects of the operations of 1745 may be performed by a GC-DCI component as described with reference to FIGs. 7 through 10.

FIG. 18 shows a flowchart illustrating a method 1800 that supports frequency selective uplink precoder indication in accordance with aspects of the present disclosure. The operations of method 1800 may be implemented by a UE 115 or its components as described herein. For example, the operations of method 1800 may be performed by a communications manager as described with reference to FIGs. 7 through 10. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware.

At 1805, the UE may receive a first stage uplink precoder indication of wideband uplink precoding. The operations of 1805 may be performed according to the methods described herein. In some examples, aspects of the operations of 1805 may be performed by a first stage uplink precoder indication component as described with reference to FIGs. 7 through 10.

At 1810, the UE may receive a second stage uplink precoder indication of a first wideband co-phase granularity for the wideband uplink precoding, a subband co-phase granularity for subband uplink precoding, or both, each of the first wideband co-phase granularity and the subband co-phase granularity being finer than a second wideband co-phase granularity indicated by the first stage uplink precoder indication. The operations of 1810 may be performed according to the methods described herein. In some examples, aspects of the operations of 1810 may be performed by a second stage uplink precoder indication component as described with reference to FIGs. 7 through 10.

At 1815, the UE may identify a payload size for a payload of the second stage uplink precoder indication, a minimum wideband co-phase indication granularity, a minimum subband co-phase indication granularity, and a number of subbands for frequency selective co-phase indication. The operations of 1815 may be performed according to the methods described herein. In some examples, aspects of the operations of 1815 may be performed by a payload interpretation component as described with reference to FIGs. 7 through 10.

At 1820, the UE may determine that the payload satisfies a co-phase indication granularity criterion based on the payload size, the number of subbands, and one or both of the minimum wideband co-phase indication granularity and the minimum subband co-phase indication granularity. The operations of 1820 may be performed according to the methods described herein. In some examples, aspects of the operations of 1820 may be performed by a payload interpretation component as described with reference to FIGs. 7 through 10.

At 1825, the UE may apply a payload interpretation rule corresponding to the co-phase indication granularity criterion to interpret the payload of the second stage uplink precoder indication. The operations of 1825 may be performed according to the methods described herein. In some examples, aspects of the operations of 1825 may be performed by a payload interpretation component as described with reference to FIGs. 7 through 10.

At 1830, the UE may generate precoded information based on the first stage uplink precoder indication and the second stage uplink precoder indication. The operations of 1830 may be performed according to the methods described herein. In some examples, aspects of the operations of 1830 may be performed by a precoded information generating component as described with reference to FIGs. 7 through 10.

At 1835, the UE may transmit a transmission generated based on the precoded information. The operations of 1835 may be performed according to the methods described herein. In some examples, aspects of the operations of 1835 may be performed by a precoded information transmitting component as described with reference to FIGs. 7 through 10.

FIG. 19 shows a flowchart illustrating a method 1900 that supports frequency selective uplink precoder indication in accordance with aspects of the present disclosure. The operations of method 1900 may be implemented by a UE 115 or its components as described herein. For example, the operations of method 1900 may be performed by a communications manager as described with reference to FIGs. 7 through 10. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware.

At 1905, the UE may receive a first stage uplink precoder indication of wideband uplink precoding. The operations of 1905 may be performed according to the methods described herein. In some examples, aspects of the operations of 1905 may be performed by a first stage uplink precoder indication component as described with reference to FIGs. 7 through 10.

At 1910, the UE may receive a second stage uplink precoder indication of a first wideband co-phase granularity for the wideband uplink precoding, a subband co-phase granularity for subband uplink precoding, or both, each of the first wideband co-phase granularity and the subband co-phase granularity being finer than a second wideband co-phase granularity indicated by the first stage uplink precoder indication. The operations of 1910 may be performed according to the methods described herein. In some examples, aspects of the operations of 1910 may be performed by a second stage uplink precoder indication component as described with reference to FIGs. 7 through 10.

At 1915, the UE may identify a payload size for a payload of the second stage uplink precoder indication, a minimum wideband co-phase indication granularity, a minimum subband co-phase indication granularity, and a number of subbands for frequency selective co-phase indication. The operations of 1915 may be performed according to the methods described herein. In some examples, aspects of the operations of 1915 may be performed by a payload interpretation component as described with reference to FIGs. 7 through 10.

At 1920, the UE may determine that the payload satisfies a co-phase indication granularity criterion based on the payload size, the number of subbands, and one or both of the minimum wideband co-phase indication granularity and the minimum subband co-phase indication granularity. The operations of 1920 may be performed according to the methods described herein. In some examples, aspects of the operations of 1920 may be performed by a payload interpretation component as described with reference to FIGs. 7 through 10.

At 1925, the UE may apply a payload interpretation rule corresponding to the co-phase indication granularity criterion to interpret the payload of the second stage uplink precoder indication. The operations of 1925 may be performed according to the methods described herein. In some examples, aspects of the operations of 1925 may be performed by a payload interpretation component as described with reference to FIGs. 7 through 10.

At 1930, the UE may apply, sequentially or in parallel, a respective co-phase indication granularity criterion of a set of different co-phase indication granularity criteria to determine that a first co-phase indication granularity criterion of the set of different co-phase indication granularity criteria is satisfied, where the first co-phase indication granularity criterion corresponds to the payload interpretation rule. The operations of 1930 may be performed according to the methods described herein. In some examples, aspects of the operations of 1930 may be performed by a payload interpretation component as described with reference to FIGs. 7 through 10.

At 1935, the UE may generate precoded information based on the first stage uplink precoder indication and the second stage uplink precoder indication. The operations of 1935 may be performed according to the methods described herein. In some examples, aspects of the operations of 1935 may be performed by a precoded information generating component as described with reference to FIGs. 7 through 10.

At 1940, the UE may transmit a transmission generated based on the precoded information. The operations of 1940 may be performed according to the methods described herein. In some examples, aspects of the operations of 1940 may be performed by a precoded information transmitting component as described with reference to FIGs. 7 through 10.

FIG. 20 shows a flowchart illustrating a method 2000 that supports frequency selective uplink precoder indication in accordance with aspects of the present disclosure. The operations of method 2000 may be implemented by a base station 105 or its components as described herein. For example, the operations of method 2000 may be performed by a communications manager as described with reference to FIGs. 11 through 14. In some examples, a base station may execute a set of instructions to control the functional elements of the base station to perform the functions described below. Additionally or alternatively, a base station may perform aspects of the functions described below using special-purpose hardware.

At 2005, the base station may transmit a first stage uplink precoder indication of wideband precoding. The operations of 2005 may be performed according to the methods described herein. In some examples, aspects of the operations of 2005 may be performed by a first stage uplink precoder indication component as described with reference to FIGs. 11 through 14.

At 2010, the base station may transmit a second stage uplink precoder indication of a first wideband co-phase granularity for the wideband precoding, a subband co-phase granularity for subband uplink precoding, or both, each of the first wideband co-phase granularity and the subband co-phase granularity being finer than a second wideband co-phase granularity indicated by the first stage uplink precoder indication. The operations of 2010 may be performed according to the methods described herein. In some examples, aspects of the operations of 2010 may be performed by a second stage uplink precoder indication component as described with reference to FIGs. 11 through 14.

At 2015, the base station may monitor for a signal generated based on information precoded in accordance with the first stage uplink precoder indication and the second stage uplink precoder indication. The operations of 2015 may be performed according to the methods described herein. In some examples, aspects of the operations of 2015 may be performed by a precoded information monitoring component as described with reference to FIGs. 11 through 14.

FIG. 21 shows a flowchart illustrating a method 2100 that supports frequency selective uplink precoder indication in accordance with aspects of the present disclosure. The operations of method 2100 may be implemented by a base station 105 or its components as described herein. For example, the operations of method 2100 may be performed by a communications manager as described with reference to FIGs. 11 through 14. In some examples, a base station may execute a set of instructions to control the functional elements of the base station to perform the functions described below. Additionally or alternatively, a base station may perform aspects of the functions described below using special-purpose hardware.

At 2105, the base station may transmit control signaling that includes the first stage uplink precoder indication and the second stage uplink precoder indication. The operations of 2105 may be performed according to the methods described herein. In some examples, aspects of the operations of 2105 may be performed by a second stage uplink precoder indication component as described with reference to FIGs. 11 through 14.

At 2110, the base station may transmit a first stage uplink precoder indication of wideband precoding. The operations of 2110 may be performed according to the methods described herein. In some examples, aspects of the operations of 2110 may be performed by a first stage uplink precoder indication component as described with reference to FIGs. 11 through 14.

At 2115, the base station may transmit a second stage uplink precoder indication of a first wideband co-phase granularity for the wideband precoding, a subband co-phase granularity for subband uplink precoding, or both, each of the first wideband co-phase granularity and the subband co-phase granularity being finer than a second wideband co-phase granularity indicated by the first stage uplink precoder indication. The operations of 2115 may be performed according to the methods described herein. In some examples, aspects of the operations of 2115 may be performed by a second stage uplink precoder indication component as described with reference to FIGs. 11 through 14.

At 2120, the base station may monitor for a signal generated based on information precoded in accordance with the first stage uplink precoder indication and the second stage uplink precoder indication. The operations of 2120 may be performed according to the methods described herein. In some examples, aspects of the operations of 2120 may be performed by a precoded information monitoring component as described with reference to FIGs. 11 through 14.

FIG. 22 shows a flowchart illustrating a method 2200 that supports frequency selective uplink precoder indication in accordance with aspects of the present disclosure. The operations of method 2200 may be implemented by a base station 105 or its components as described herein. For example, the operations of method 2200 may be performed by a communications manager as described with reference to FIGs. 11 through 14. In some examples, a base station may execute a set of instructions to control the functional elements of the base station to perform the functions described below. Additionally or alternatively, a base station may perform aspects of the functions described below using special-purpose hardware.

At 2205, the base station may transmit control signaling that configures a UE with a group temporary identifier and a search offset. The operations of 2205 may be performed according to the methods described herein. In some examples, aspects of the operations of 2205 may be performed by a GC-DCI component as described with reference to FIGs. 11 through 14.

At 2210, the base station may transmit a first stage uplink precoder indication of wideband precoding. The operations of 2210 may be performed according to the methods described herein. In some examples, aspects of the operations of 2210 may be performed by a first stage uplink precoder indication component as described with reference to FIGs. 11 through 14.

At 2215, the base station may transmit a second stage uplink precoder indication of a first wideband co-phase granularity for the wideband precoding, a subband co-phase granularity for subband uplink precoding, or both, each of the first wideband co-phase granularity and the subband co-phase granularity being finer than a second wideband co-phase granularity indicated by the first stage uplink precoder indication. The operations of 2215 may be performed according to the methods described herein. In some examples, aspects of the operations of 2215 may be performed by a second stage uplink precoder indication component as described with reference to FIGs. 11 through 14.

At 2220, the base station may monitor for a signal generated based on information precoded in accordance with the first stage uplink precoder indication and the second stage uplink precoder indication. The operations of 2220 may be performed according to the methods described herein. In some examples, aspects of the operations of 2220 may be performed by a precoded information monitoring component as described with reference to FIGs. 11 through 14.

FIG. 23 shows a flowchart illustrating a method 2300 that supports frequency selective uplink precoder indication in accordance with aspects of the present disclosure. The operations of method 2300 may be implemented by a base station 105 or its components as described herein. For example, the operations of method 2300 may be performed by a communications manager as described with reference to FIGs. 11 through 14. In some examples, a base station may execute a set of instructions to control the functional elements of the base station to perform the functions described below. Additionally or alternatively, a base station may perform aspects of the functions described below using special-purpose hardware.

At 2305, the base station may transmit a first stage uplink precoder indication of wideband precoding. The operations of 2305 may be performed according to the methods described herein. In some examples, aspects of the operations of 2305 may be performed by a first stage uplink precoder indication component as described with reference to FIGs. 11 through 14.

At 2310, the base station may identify a payload size for a payload of the second stage uplink precoder indication, a minimum wideband co-phase indication granularity, a minimum subband co-phase indication granularity, and a number of subbands for frequency selective co-phase indication. The operations of 2310 may be performed according to the methods described herein. In some examples, aspects of the operations of 2310 may be performed by a payload generating component as described with reference to FIGs. 11 through 14.

At 2315, the base station may determine that the payload satisfies a co-phase indication granularity criterion based on the payload size, the number of subbands, and one or both of the minimum wideband co-phase indication granularity and the minimum subband co-phase indication granularity. The operations of 2315 may be performed according to the methods described herein. In some examples, aspects of the operations of 2315 may be performed by a payload generating component as described with reference to FIGs. 11 through 14.

At 2320, the base station may generate the payload of the second stage uplink precoder indication in accordance with a payload interpretation rule corresponding to the co-phase indication granularity criterion. The operations of 2320 may be performed according to the methods described herein. In some examples, aspects of the operations of 2320 may be performed by a payload generating component as described with reference to FIGs. 11 through 14.

At 2325, the base station may transmit a second stage uplink precoder indication of a first wideband co-phase granularity for the wideband precoding, a subband co-phase granularity for subband uplink precoding, or both, each of the first wideband co-phase granularity and the subband co-phase granularity being finer than a second wideband co-phase granularity indicated by the first stage uplink precoder indication. The operations of 2325 may be performed according to the methods described herein. In some examples, aspects of the operations of 2325 may be performed by a second stage uplink precoder indication component as described with reference to FIGs. 11 through 14.

At 2330, the base station may monitor for a signal generated based on information precoded in accordance with the first stage uplink precoder indication and the second stage uplink precoder indication. The operations of 2330 may be performed according to the methods described herein. In some examples, aspects of the operations of 2330 may be performed by a precoded information monitoring component as described with reference to FIGs. 11 through 14.

Embodiment 1. A method for wireless communications by a UE, comprising: receiving a first stage uplink precoder indication of wideband uplink precoding; receiving a second stage uplink precoder indication of a first wideband co-phase granularity for the wideband uplink precoding, a subband co-phase granularity for subband uplink precoding, or both, each of the first wideband co-phase granularity and the subband co-phase granularity being finer than a second wideband co-phase granularity indicated by the first stage uplink precoder indication; generating precoded information based at least in part on the first stage uplink precoder indication and the second stage uplink precoder indication; and transmitting a transmission generated based at least in part on the precoded information.

Embodiment 2. The method of embodiment 1, further comprising: identifying a resource for transmitting the transmission.

Embodiment 3. The method of embodiment 2, wherein identifying the resource comprises: receiving control signaling that configures the UE with the resource for transmitting the transmission.

Embodiment 4. The method of any of embodiments 2 to 3, further comprising: receiving control signaling that comprises the first stage uplink precoder indication and the second stage uplink precoder indication.

Embodiment 5. The method of any of embodiments 2 to 3, further comprising: receiving DCI that comprises the first stage uplink precoder indication and the second stage uplink precoder indication.

Embodiment 6. The method of any of embodiments 2 to 3, wherein receiving the first stage uplink precoder indication and the second stage uplink precoder indication comprises: receiving first DCI that comprises the first stage uplink precoder indication and second DCI that comprises the second stage uplink precoder indication.

Embodiment 7. The method of any of embodiments 2 to 3, wherein receiving the first stage uplink precoder indication and the second stage uplink precoder indication comprises: receiving a RRC configuration that comprises the first stage uplink precoder indication and DCI that comprises the second stage uplink precoder indication.

Embodiment 8. The method of any of embodiments 1 to 7, further comprising: receiving DCI that schedules the UE to transmit the transmission.

Embodiment 9. The method of embodiment 8, wherein the DCI comprises the first stage uplink precoder indication and the second stage uplink precoder indication.

Embodiment 10. The method of embodiment 9, wherein the DCI comprises the first stage uplink precoder indication and second DCI comprises the second stage uplink precoder indication.

Embodiment 11. The method of any of embodiments 1 to 10, further comprising: receiving control signaling that configures the UE with a group temporary identifier and a search offset; and monitoring a search space for the second stage uplink precoder indication based at least in part on the group temporary identifier and the search offset.

Embodiment 12. The method of embodiment 11, wherein receiving the control signaling further comprises: receiving the control signaling that configures the UE with a plurality of different second stage uplink precoder configurations; decoding the search space to obtain DCI based at least in part on the group temporary identifier and the search offset; and selecting a first configuration from the plurality of different second stage uplink precoder configurations based at least in part on the DCI, wherein the precoded information is generated based at least in part on the first configuration.

Embodiment 13. The method of embodiment 11, wherein receiving the control signaling further comprises: receiving the control signaling that configures the UE with a plurality of different second stage uplink precoder configurations and a plurality of indexes respectively associated with the plurality of different second stage uplink precoder configurations; decoding the search space to obtain DCI and a first index of the plurality of indexes based at least in part on the group temporary identifier and the search offset; and selecting a first configuration from the plurality of different second stage uplink precoder configurations based at least in part on the DCI and the first index, wherein the precoded information is generated based at least in part on the first configuration.

Embodiment 14. The method of any of embodiments 1 to 13, further comprising: identifying a payload size for a payload of the second stage uplink precoder indication, a minimum wideband co-phase indication granularity, a minimum subband co-phase indication granularity, and a number of subbands for frequency selective co-phase indication; determining that the payload satisfies a co-phase indication granularity criterion based at least in part on the payload size, the number of subbands, and one or both of the minimum wideband co-phase indication granularity and the minimum subband co-phase indication granularity; and applying a payload interpretation rule corresponding to the co-phase indication granularity criterion to interpret the payload of the second stage uplink precoder indication.

Embodiment 15. The method of embodiment 14, wherein determining that the payload satisfies the co-phase indication granularity criterion comprises: applying, sequentially or in parallel, a respective co-phase indication granularity criterion of a plurality of different co-phase indication granularity criteria to determine that a first co-phase indication granularity criterion of the plurality of different co-phase indication granularity criteria is satisfied, wherein the first co-phase indication granularity criterion corresponds to the payload interpretation rule.

Embodiment 16. The method of any of embodiments 14 to 15, wherein the identifying further comprises: identifying a set of parameters comprising one or more of the payload size for the payload of the second stage uplink precoder indication, the minimum wideband co-phase indication granularity, the minimum subband co-phase indication granularity, and the number of subbands for frequency selective co-phase indication, wherein the identifying is based at least in part on at least one predefinition for one or more parameters of the set of parameters stored in a storage device of the UE, receiving a RRC configuration indicating one or more parameters of the set of parameters, receiving DCI indicating one or more parameters of the set of parameters, or any combination thereof.

Embodiment 17. The method of any of embodiments 14 to 15, wherein the co-phase indication granularity criterion is that, using bits of the payload, the subband co-phase granularity at least satisfies the minimum subband co-phase indication granularity for each subband of a plurality of subbands, and wherein the payload interpretation rule is that the subband co-phase granularity for each subband of the plurality of subbands is indicated using respective bit subsets of the payload each having an equal number of bits that indicate a subband specific co-phase with equal co-phase granularity for each of the plurality of subbands.

Embodiment 18. The method of any of embodiments 14 to 15, wherein the co-phase indication granularity criterion is that, using bits of the payload, the subband co-phase granularity does not satisfy the minimum subband co-phase indication granularity, that, using the bits of the payload, the first wideband co-phase granularity at least satisfies the minimum wideband co-phase indication granularity, and that, apart from a subset of the bits of the payload used for indicating the first wideband co-phase granularity, remaining bits of the payload are capable of subband differential co-phase indication that satisfies the minimum subband co-phase indication granularity; and wherein the payload interpretation rule is that a first bit subset of the payload indicates a wideband co-phase that satisfies the minimum wideband co-phase indication granularity and that the subband co-phase granularity for each subband of a plurality of subbands is differentially indicated relative to the wideband co-phase using respective bit subsets in a remainder of the payload, the subband co-phase granularity for each subband of the plurality of subbands having equal co-phase granularity.

Embodiment 19. The method of any of embodiments 14 to 15, wherein the co-phase indication granularity criterion is that, using bits of the payload, the first wideband co-phase granularity at least satisfies the minimum wideband co-phase indication granularity and that, apart from a subset of the bits of the payload used for indicating the first wideband co-phase granularity, remaining bits of the payload are not capable of subband differential co-phase indication that satisfies the minimum subband co-phase indication granularity; and wherein the payload interpretation rule is that a first bit subset of the payload indicates a wideband co-phase that satisfies the minimum wideband co-phase indication granularity.

Embodiment 20. The method of any of embodiments 14 to 15, wherein the co-phase indication granularity criterion is that, using bits of the payload, the first wideband co-phase granularity at least satisfies the minimum wideband co-phase indication granularity and that, apart from a subset of the bits of the payload used for indicating the first wideband co-phase granularity, remaining bits of the payload are not capable of subband differential co-phase indication that satisfies the minimum subband co-phase indication granularity; and wherein the payload interpretation rule is that bits of the payload indicate a wideband co-phase for each antenna port pair that has a finer wideband co-phase granularity than the minimum wideband co-phase indication granularity.

Embodiment 21. The method of embodiment 20, wherein the finer wideband co-phase granularity maximizes wideband co-phase granularity corresponding to the payload size.

Embodiment 22. The method of any of embodiments 14 to 34, wherein receiving the control signaling further comprises: receiving the control signaling that configures the UE with a plurality of different second stage uplink precoder configurations and a plurality of indexes respectively associated with the plurality of different second stage uplink precoder configurations; decoding the search space to obtain DCI and a first index of the plurality of indexes based at least in part on the group temporary identifier and the search offset; and selecting a first configuration from the plurality of different second stage uplink precoder configurations based at least in part on the DCI and the first index, wherein the payload of the second stage uplink precoder indication corresponds to the first configuration.

Embodiment 22. The method of any of embodiments 1 to 14, further comprising: identifying a payload size for a payload of the second stage uplink precoder indication, a fixed wideband co-phase indication granularity, a fixed subband co-phase indication granularity, and a number of subbands for frequency selective co-phase indication; determining that the payload satisfies a co-phase indication granularity criterion based at least in part on the payload size, the number of subbands, and one or both of the fixed wideband co-phase indication granularity and the fixed subband co-phase indication granularity; and applying a payload interpretation rule corresponding to the co-phase indication granularity criterion to interpret the payload of the second stage uplink precoder indication.

Embodiment 23. The method of embodiment 22, wherein determining that the payload satisfies the co-phase indication granularity criterion comprises: applying, sequentially or in parallel, a respective co-phase indication granularity criterion of a plurality of different co-phase indication granularity criteria to determine that a first co-phase indication granularity criterion of the plurality of different co-phase indication granularity criteria is satisfied, wherein the first co-phase indication granularity criterion corresponds to the payload interpretation rule.

Embodiment 24. The method of any of embodiments 22 to 23, wherein the identifying further comprises: identifying a set of parameters comprising one or more of the payload size for the payload of the second stage uplink precoder indication, the fixed wideband co-phase indication granularity, the fixed subband co-phase indication granularity, and the number of subbands for frequency selective co-phase indication, wherein the identifying is based at least in part on at least one predefinition for one or more parameters of the set of parameters stored in a storage device of the UE, receiving a RRC configuration indicating one or more parameters of the set of parameters, receiving DCI indicating one or more parameters of the set of parameters, or any combination thereof.

Embodiment 25. The method of any of embodiments 22 to 23, wherein the co-phase indication granularity criterion is that, using bits of the payload, the subband co-phase granularity satisfies the fixed subband co-phase indication granularity, and wherein the payload interpretation rule is that the subband co-phase granularity for each subband of a plurality of subbands is indicated using a same number of bits of the payload to indicate subband specific co-phase that satisfies the fixed subband co-phase indication granularity.

Embodiment 26. The method of any of embodiments 22 to 23, wherein the co-phase indication granularity criterion is that, using bits of the payload, the subband co-phase granularity does not satisfy the fixed subband co-phase indication granularity, that, using the bits of the payload, the first wideband co-phase granularity satisfies the fixed wideband co-phase indication granularity, and that, apart from a subset of the bits of the payload used for indicating the first wideband co-phase granularity, remaining bits of the payload are capable of subband differential co-phase indication that satisfies the fixed subband co-phase indication granularity; and wherein the payload interpretation rule is that a first bit subset of the payload indicates a wideband co-phase that satisfies the fixed wideband co-phase indication granularity and that the subband co-phase granularity for each subband of a plurality of subbands is differentially indicated relative to the wideband co-phase using respective bit subsets of the remaining bits of the payload, the subband co-phase granularity for each subband of the plurality of subbands satisfying the fixed subband co-phase indication granularity.

Embodiment 27. The method of any of embodiments 22 to 23, wherein the co-phase indication granularity criterion is that, using bits of the payload, the first wideband co-phase granularity at least satisfies the fixed wideband co-phase indication granularity and that, apart from a subset of the bits of the payload used for indicating the first wideband co-phase granularity, remaining bits of the payload are not capable of satisfying the fixed subband co-phase indication granularity for each subband of a plurality of subbands; and wherein the payload interpretation rule is that a first bit subset of the payload indicates a wideband co-phase that satisfies the fixed wideband co-phase indication granularity, that a second bit subset of the payload indicates a subband index bitmap, and that, for at least one subband indicated in the subband index bitmap, a third subset of the payload provides a differential subband co-phase indication relative to the wideband co-phase that satisfies the fixed subband co-phase indication granularity.

Embodiment 28. The method of embodiment 27, wherein the bitmap indicates positive and negative subband indexes from the plurality of subbands, wherein a first subband subset of the plurality of subbands with positive indexes are indicated with subband co-phases and a second subband subset of the plurality of subbands with negative indexes are not indicated with subband co-phases.

Embodiment 29. The method of embodiment 28, wherein the subband co-phase granularity for the first subband subset of the plurality of subbands with positive indexes satisfies the fixed subband co-phase indication granularity.

Embodiment 30. The method of any of embodiments 22 to 23, wherein the co-phase indication granularity criterion is that, using bits of the payload, the first wideband co-phase granularity at least satisfies the fixed wideband co-phase indication granularity and that, apart from a subset of the bits of the payload used for indicating the first wideband co-phase granularity, remaining bits of the payload are not capable of satisfying the fixed subband co-phase indication granularity for each subband of a plurality of subbands; and wherein the payload interpretation rule is that a first bit subset of the payload indicates a wideband co-phase that satisfies the fixed wideband co-phase indication granularity, that a second bit subset of the payload indicates a subband selection pattern, and that, for at least one subband indicated in the subband selection pattern, a third bit subset of the payload provides a differential subband co-phase indication relative to the wideband co-phase that satisfies the fixed subband co-phase indication granularity.

Embodiment 31. The method of embodiment 30, wherein the second bit subset is a combinatorial number that indicates the subband selection pattern from among a plurality of candidate subband selection patterns.

Embodiment 32. The method of embodiment 30, wherein the subband co-phase granularity for the at least one subband indicated in the subband selection pattern indicted satisfies the fixed subband co-phase indication granularity.

Embodiment 33. The method of any of embodiments 22 to 23, wherein the co-phase indication granularity criterion is that, using bits of the payload, the first wideband co-phase granularity at least satisfies the fixed wideband co-phase indication granularity and that, apart from a subset of the bits of the payload used for indicating the first wideband co-phase granularity, remaining bits of the payload are not capable of satisfying the fixed subband co-phase indication granularity for each subband of a plurality of subbands; and wherein the payload interpretation rule is that a first bit subset of the payload indicates a wideband co-phase that satisfies the fixed wideband co-phase indication granularity, that a second bit subset of the payload indicates an adaptive subband selection rule, and that, for at least one subband of the plurality of subbands indicated in the adaptive subband selection rule, a third bit subset of the payload provides a differential subband co-phase indication relative to the wideband co-phase that satisfies the fixed subband co-phase indication granularity.

Embodiment 34. The method of embodiment 33, wherein the adaptive subband selection rule indicates to interpret the payload as selecting, starting from a nth subband of the plurality of subbands, every (K+n) th, (2K+n) th, (3K+n) th subband, where K is selected so that the third bit subset provides differential subband co-phase indication that satisfies the fixed subband co-phase indication granularity, and n is preconfigured or RRC configured.

Embodiment 35. The method of any of embodiments 14 to 34, wherein receiving the control signaling further comprises: receiving the control signaling that configures the UE with a plurality of different second stage uplink precoder configurations and a plurality of indexes respectively associated with the plurality of different second stage uplink precoder configurations; decoding the search space to obtain DCI and a first index of the plurality of indexes based at least in part on the group temporary identifier and the search offset; and selecting a first configuration from the plurality of different second stage uplink precoder configurations based at least in part on the DCI and the first index, wherein the payload of the second stage uplink precoder indication corresponds to the first configuration.

Embodiment 36. The method of any of embodiments 1 to 35, wherein the second stage uplink precoder indication indicates the first wideband co-phase granularity for at least one antenna port pair of a plurality of antenna ports, wherein the transmission is transmitted using the plurality of antenna ports.

Embodiment 37. The method of any of embodiments 1 to 36, wherein the second stage uplink precoder indication indicates the subband co-phase granularity for at least one antenna port pair of a plurality of antenna ports, wherein the transmission is transmitted using the plurality of antenna ports.

Embodiment 38. The method of any of embodiments 1 to 37, wherein transmitting the transmission comprises: transmitting the transmission in a PUSCH.

Embodiment 39. The method of any of embodiments 1 to 38, wherein the transmission is a non-configured grant transmission or a configured grant transmission.

Embodiment 40. The method of any of embodiments 1 to 39, wherein the first stage uplink precoder indication is an uplink PMI.

Embodiment 41. A method for wireless communications by a base station, comprising: transmitting a first stage uplink precoder indication of wideband precoding; transmitting a second stage uplink precoder indication of a first wideband co-phase granularity for the wideband precoding, a subband co-phase granularity for subband uplink precoding, or both, each of the first wideband co-phase granularity and the subband co-phase granularity being finer than a second wideband co-phase granularity indicated by the first stage uplink precoder indication; and monitoring for a signal generated based at least in part on information precoded in accordance with the first stage uplink precoder indication and the second stage uplink precoder indication.

Embodiment 42. The method of embodiment 41, further comprising: transmitting control signaling that configures a UE with a resource for transmitting the signal.

Embodiment 43. The method of embodiment 41, further comprising: transmitting control signaling that comprises the first stage uplink precoder indication and the second stage uplink precoder indication.

Embodiment 44. The method of any of embodiments 41 to 43, further comprising: transmitting DCI that comprises the first stage uplink precoder indication and the second stage uplink precoder indication.

Embodiment 45. The method of any of embodiments 41 to 44, wherein transmitting the first stage uplink precoder indication and the second stage uplink precoder indication comprises: transmitting a RRC configuration that comprises the first stage uplink precoder indication and DCI that comprises the second stage uplink precoder indication.

Embodiment 46. The method of any of embodiments 41 to 45, further comprising: transmitting DCI that schedules the UE to transmit the signal.

Embodiment 47. The method of embodiment 46, wherein the DCI comprises the second stage uplink precoder indication.

Embodiment 48. The method of embodiment 47, wherein the DCI comprises the first stage uplink precoder indication.

Embodiment 49. The method of any of embodiments 41 to 48, further comprising: transmitting control signaling that configures a UE with a group temporary identifier and a search offset.

Embodiment 50. The method of embodiment 49, wherein transmitting the control signaling comprises: transmitting the control signaling that configures the UE with a plurality of different second stage uplink precoder configurations.

Embodiment 51. The method of embodiment 49, wherein transmitting the control signaling comprises: transmitting the control signaling that configures the UE with a plurality of different second stage uplink precoder configurations and a plurality of indexes respectively associated with the plurality of different second stage uplink precoder configurations.

Embodiment 52. The method of any of embodiments 41 to 51, wherein the first stage uplink precoder indication is a PMI.

Embodiment 53. The method of any of embodiments 41 to 52, further comprising: identifying a payload size for a payload of the second stage uplink precoder indication, a minimum wideband co-phase indication granularity, a minimum subband co-phase indication granularity, and a number of subbands for frequency selective co-phase indication; determining that the payload satisfies a co-phase indication granularity criterion based at least in part on the payload size, the number of subbands, and one or both of the minimum wideband co-phase indication granularity and the minimum subband co-phase indication granularity; and generating the payload of the second stage uplink precoder indication in accordance with a payload interpretation rule corresponding to the co-phase indication granularity criterion.

Embodiment 54. The method of embodiment 53, wherein determining that the payload satisfies the co-phase indication granularity criterion comprises: applying, sequentially or in parallel, a respective co-phase indication granularity criterion of a plurality of different co-phase indication granularity criteria to determine that a first co-phase indication granularity criterion of the plurality of different co-phase indication granularity criteria is satisfied, wherein the first co-phase indication granularity criterion corresponds to the payload interpretation rule.

Embodiment 55. The method of any of embodiments 53 to 54, wherein the identifying further comprises: identifying a set of parameters comprising one or more of the payload size for the payload of the second stage uplink precoder indication, the minimum wideband co-phase indication granularity, the minimum subband co-phase indication granularity, and the number of subbands for frequency selective co-phase indication, wherein the identifying is based at least in part on at least one predefinition for one or more parameters of the set of parameters, a RRC configuration indicating one or more parameters of the set of parameters, DCI indicating one or more parameters of the set of parameters, or any combination thereof.

Embodiment 56. The method of any of embodiments 53 to 55, wherein the co-phase indication granularity criterion is that, using bits of the payload, the subband co-phase granularity at least satisfies the minimum subband co-phase indication granularity for each subband of a plurality of subbands, and wherein the payload interpretation rule is that the subband co-phase granularity for each subband of the plurality of subbands is indicated using respective bit subsets of the payload each having an equal number of bits that indicate a subband specific co-phase with equal co-phase granularity for each of the plurality of subbands.

Embodiment 57. The method of any of embodiments 53 to 55, wherein the co-phase indication granularity criterion is that, using bits of the payload, the subband co-phase granularity does not satisfy the minimum subband co-phase indication granularity, that, using the bits of the payload, the first wideband co-phase granularity at least satisfies the minimum wideband co-phase indication granularity, and that, apart from a subset of the bits of the payload used for indicating the first wideband co-phase granularity, remaining bits of the payload are capable of subband differential co-phase indication that satisfies the minimum subband co-phase indication granularity; and wherein the payload interpretation rule is that a first bit subset of the payload indicates a wideband co-phase that satisfies the minimum wideband co-phase indication granularity and that the subband co-phase granularity for each subband of a plurality of subbands is differentially indicated relative to the wideband co-phase using respective bit subsets in a remainder of the payload, the subband co-phase granularity for each subband of the plurality of subbands having equal co-phase granularity.

Embodiment 58. The method of any of embodiments 53 to 55, wherein the co-phase indication granularity criterion is that, using bits of the payload, the first wideband co-phase granularity at least satisfies the minimum wideband co-phase indication granularity and that, apart from a subset of the bits of the payload used for indicating the first wideband co-phase granularity, remaining bits of the payload are not capable of subband differential co-phase indication that satisfies the minimum subband co-phase indication granularity, and wherein the payload interpretation rule is that a first bit subset of the payload indicates a wideband co-phase that satisfies the minimum wideband co-phase indication granularity.

Embodiment 59. The method of any of embodiments 53 to 55, wherein the co-phase indication granularity criterion is that, using bits of the payload, the first wideband co-phase granularity at least satisfies the minimum wideband co-phase indication granularity and that, apart from a subset of the bits of the payload used for indicating the first wideband co-phase granularity, remaining bits of the payload are not capable of subband differential co-phase indication that satisfies the minimum subband co-phase indication granularity; and wherein the payload interpretation rule is that bits of the payload indicate a wideband co-phase for each antenna port pair that has a finer wideband co-phase granularity than the minimum wideband co-phase indication granularity.

Embodiment 60. The method of embodiment 59, wherein the finer wideband co-phase granularity maximizes wideband co-phase granularity corresponding to the payload size.

Embodiment 61. The method of embodiment 41, further comprising: identifying a payload size for a payload of the second stage uplink precoder indication, a fixed wideband co-phase indication granularity, a fixed subband co-phase indication granularity, and a number of subbands for frequency selective co-phase indication; determining that the payload satisfies a co-phase indication granularity criterion based at least in part on the payload size, the number of subbands, and one or both of the fixed wideband co-phase indication granularity and the fixed subband co-phase indication granularity; and generating the payload of the second stage uplink precoder indication in accordance with a payload interpretation rule corresponding to the co-phase indication granularity criterion.

Embodiment 62. The method of embodiment 61, wherein determining that the payload satisfies the co-phase indication granularity criterion comprises: applying, sequentially or in parallel, a respective co-phase indication granularity criterion of a plurality of different co-phase indication granularity criteria to determine that a first co-phase indication granularity criterion of the plurality of different co-phase indication granularity criteria is satisfied, wherein the first co-phase indication granularity criterion corresponds to the payload interpretation rule.

Embodiment 63. The method of any of embodiments 61 to 62, wherein the identifying further comprises: identifying a set of parameters comprising one or more of the payload size for the payload of the second stage uplink precoder indication, the fixed wideband co-phase indication granularity, the fixed subband co-phase indication granularity, and the number of subbands for frequency selective co-phase indication, wherein the identifying is based at least in part on at least one predefinition for one or more parameters of the set of parameters, a RRC configuration indicating one or more parameters of the set of parameters, DCI indicating one or more parameters of the set of parameters, or any combination thereof.

Embodiment 64. The method of any of embodiments 61 to 62, wherein the co-phase indication granularity criterion is that, using bits of the payload, the subband co-phase granularity satisfies the fixed subband co-phase indication granularity, and wherein the payload interpretation rule is that the subband co-phase granularity for each subband of a plurality of subbands is indicated using a same number of bits of the payload to indicate subband specific co-phase that satisfies the fixed subband co-phase indication granularity.

Embodiment 65. The method of any of embodiments 61 to 62, wherein the co-phase indication granularity criterion is that, using bits of the payload, the subband co-phase granularity does not satisfy the fixed subband co-phase indication granularity, that, using the bits of the payload, the first wideband co-phase granularity satisfies the fixed wideband co-phase indication granularity, and that, apart from a subset of the bits of the payload used for indicating the first wideband co-phase granularity, remaining bits of the payload are capable of subband differential co-phase indication that satisfies the fixed subband co-phase indication granularity; and wherein the payload interpretation rule is that a first bit subset of the payload indicates a wideband co-phase that satisfies the fixed wideband co-phase indication granularity and that the subband co-phase granularity for each subband of a plurality of subbands is differentially indicated relative to the wideband co-phase using respective bit subsets of the remaining bits of the payload, the subband co-phase granularity for each subband of the plurality of subbands satisfying the fixed subband co-phase indication granularity.

Embodiment 66. The method of any of embodiments 61 to 62, wherein: the co-phase indication granularity criterion is that, using bits of the payload, the first wideband co-phase granularity at least satisfies the fixed wideband co-phase indication granularity and that, apart from a subset of the bits of the payload used for indicating the first wideband co-phase granularity, remaining bits of the payload are not capable of satisfying the fixed subband co-phase indication granularity for each subband of a plurality of subbands; and wherein the payload interpretation rule is that a first bit subset of the payload indicates a wideband co-phase that satisfies the fixed wideband co-phase indication granularity, that a second bit subset of the payload indicates a subband index bitmap, and that, for at least one subband indicated in the subband index bitmap, a third subset of the payload provides a differential subband co-phase indication relative to the wideband co-phase that satisfies the fixed subband co-phase indication granularity.

Embodiment 67. The method of embodiment 66, wherein the subband index bitmap indicates positive and negative subband indexes from the plurality of subbands, wherein a first subband subset of the plurality of subbands with positive indexes are indicated with subband co-phases and a second subband subset of the plurality of subbands with negative indexes are not indicated with subband co-phases.

Embodiment 68. The method of embodiment 67, wherein the subband co-phase granularity for the first subband subset of the plurality of subbands with positive indexes satisfies the fixed subband co-phase indication granularity.

Embodiment 69. The method of any of embodiments 61 to 68, wherein: the co-phase indication granularity criterion is that, using bits of the payload, the first wideband co-phase granularity at least satisfies the fixed wideband co-phase indication granularity and that, apart from a subset of the bits of the payload used for indicating the first wideband co-phase granularity, remaining bits of the payload are not capable of satisfying the fixed subband co-phase indication granularity for each subband of a plurality of subbands; and wherein the payload interpretation rule is that a first bit subset of the payload indicates a wideband co-phase that satisfies the fixed wideband co-phase indication granularity, that a second bit subset of the payload indicates a subband selection pattern, and that, for at least one subband indicated in the subband selection pattern, a third bit subset of the payload provides a differential subband co-phase indication relative to the wideband co-phase that satisfies the fixed subband co-phase indication granularity.

Embodiment 70. The method of embodiment 69, wherein the second bit subset is a combinatorial number that indicates the subband selection pattern from among a plurality of candidate subband selection patterns.

Embodiment 71. The method of embodiment 69, wherein the subband co-phase granularity for the at least one subband indicated in the subband selection pattern indicted satisfies the fixed subband co-phase indication granularity.

Embodiment 72. The method of any of embodiments 61 to 71, wherein the co-phase indication granularity criterion is that, using bits of the payload, the first wideband co-phase granularity at least satisfies the fixed wideband co-phase indication granularity and that, apart from a subset of the bits of the payload used for indicating the first wideband co-phase granularity, remaining bits of the payload are not capable of satisfying the fixed subband co-phase indication granularity for each subband of a plurality of subbands; and wherein the payload interpretation rule is that a first bit subset of the payload indicates a wideband co-phase that satisfies the fixed wideband co-phase indication granularity, that a second bit subset of the payload indicates an adaptive subband selection rule, and that, for at least one subband of the plurality of subbands indicated in the adaptive subband selection rule, a third bit subset of the payload provides a differential subband co-phase indication relative to the wideband co-phase that satisfies the fixed subband co-phase indication granularity.

Embodiment 73. The method of embodiment 72, wherein the adaptive subband selection rule indicates to interpret the payload as selecting, starting from a nth subband of the plurality of subbands, every (K+n) th, (2K+n) th, (3K+n) th subband, where K is selected so that the third bit subset provides differential subband co-phase indication that satisfies the fixed subband co-phase indication granularity, and n is preconfigured or RRC configured.

Embodiment 74. The method of any of embodiments 41 to 73, wherein receiving the control signaling further comprises: transmitting the control signaling that configures the UE with a plurality of different second stage uplink precoder configurations and a plurality of indexes respectively associated with the plurality of different second stage uplink precoder configurations.

Embodiment 75. The method of any of embodiments 41 to 74, wherein the second stage uplink precoder indication indicates the wideband co-phase granularity for at least one antenna port pair of a plurality of antenna ports.

Embodiment 76. The method of any of embodiments 41 to 75, wherein the second stage uplink precoder indication indicates the subband co-phase granularity for at least one antenna port pair of a plurality of antenna ports.

Embodiment 77. The method of any of embodiments 41 to 76, further comprising: receiving the signal in a PUSCH.

Embodiment 78. The method of embodiment 77, wherein the signal is a non-configured grant transmission or a configured grant transmission.

Embodiment 79. The method of any of embodiments 41 to 78, wherein the first stage uplink precoder indication is an uplink PMI.

Embodiment 80. An apparatus comprising at least one means for performing a method of any of embodiments 1 to 40.

Embodiment 81. An apparatus comprising at least one means for performing a method of any of embodiments 41 to 79.

Embodiment 82. An apparatus for wireless communication, comprising: a processor; memory in communication with the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform a method of any of embodiments 1 to 40.

Embodiment 83: An apparatus for wireless communication, comprising: a processor; memory in communication with the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform a method of any of embodiments 41 to 79.

Embodiment 84: A non-transitory computer-readable medium storing code for wireless communications, the code comprising instructions executable by a processor to perform a method of any of embodiments 1 to 40.

Embodiment 85: A non-transitory computer-readable medium storing code for wireless communications, the code comprising instructions executable by a processor to perform a method of any of embodiments 41 to 79.

It should be noted that the methods described herein describe possible implementations, and that the operations and the steps may be rearranged or otherwise modified and that other implementations are possible. Further, aspects from two or more of the methods may be combined.

Techniques described herein may be used for various wireless communications systems such as code division multiple access (CDMA) , time division multiple access (TDMA) , frequency division multiple access (FDMA) , orthogonal frequency division multiple access (OFDMA) , single carrier frequency division multiple access (SC-FDMA) , and other systems. A CDMA system may implement a radio technology such as CDMA2000, Universal Terrestrial Radio Access (UTRA) , etc. CDMA2000 covers IS-2000, IS-95, and IS-856 standards. IS-2000 Releases may be commonly referred to as CDMA2000 1X, 1X, etc. IS-856 (TIA-856) is commonly referred to as CDMA2000 1xEV-DO, High Rate Packet Data (HRPD) , etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. A TDMA system may implement a radio technology such as Global System for Mobile Communications (GSM) .

An OFDMA system may implement a radio technology such as Ultra Mobile Broadband (UMB) , Evolved UTRA (E-UTRA) , Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi) , IEEE 802.16 (WiMAX) , IEEE 802.20, Flash-OFDM, etc. UTRA and E-UTRA are part of Universal Mobile Telecommunications System (UMTS) . LTE, LTE-A, and LTE-A Pro are releases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, LTE-A Pro, NR, and GSM are described in documents from the organization named “3rd Generation Partnership Project” (3GPP) . CDMA2000 and UMB are described in documents from an organization named “3rd Generation Partnership Project 2” (3GPP2) . The techniques described herein may be used for the systems and radio technologies mentioned herein as well as other systems and radio technologies. While aspects of an LTE, LTE-A, LTE-A Pro, or NR system may be described for purposes of example, and LTE, LTE-A, LTE-A Pro, or NR terminology may be used in much of the description, the techniques described herein are applicable beyond LTE, LTE-A, LTE-A Pro, or NR applications.

A macro cell generally covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscriptions with the network provider. A small cell may be associated with a lower-powered base station, as compared with a macro cell, and a small cell may operate in the same or different (e.g., licensed, unlicensed) frequency bands as macro cells. Small cells may include pico cells, femto cells, and micro cells according to various examples. A pico cell, for example, may cover a small geographic area and may allow unrestricted access by UEs with service subscriptions with the network provider. A femto cell may also cover a small geographic area (e.g., a home) and may provide restricted access by UEs having an association with the femto cell (e.g., UEs in a closed subscriber group (CSG) , UEs for users in the home, and the like) . An eNB for a macro cell may be referred to as a macro eNB. An eNB for a small cell may be referred to as a small cell eNB, a pico eNB, a femto eNB, or a home eNB. An eNB may support one or multiple (e.g., two, three, four, and the like) cells, and may also support communications using one or multiple component carriers.

The wireless communications systems described herein may support synchronous or asynchronous operation. For synchronous operation, the base stations may have similar frame timing, and transmissions from different base stations may be approximately aligned in time. For asynchronous operation, the base stations may have different frame timing, and transmissions from different base stations may not be aligned in time. The techniques described herein may be used for either synchronous or asynchronous operations.

Information and signals described herein may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

The various illustrative blocks and modules described in connection with the disclosure herein may be implemented or performed with a general-purpose processor, a DSP, an ASIC, an FPGA, or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration) .

The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Other examples and implementations are within the scope of the disclosure and appended claims. For example, due to the nature of software, functions described herein can be implemented using software executed by a processor, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations.

Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A non-transitory storage medium may be any available medium that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, non-transitory computer-readable media may include RAM, ROM, electrically erasable programmable ROM (EEPROM) , flash memory, compact disk (CD) ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that can be used to carry or store desired program code means in the form of instructions or data structures and that can be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL) , or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, include CD, laser disc, optical disc, digital versatile disc (DVD) , floppy disk and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above are also included within the scope of computer-readable media.

As used herein, including in the claims, “or” as used in a list of items (e.g., a list of items prefaced by a phrase such as “at least one of” or “one or more of” ) indicates an inclusive list such that, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (e.g., A and B and C) . Also, as used herein, the phrase “based on” shall not be construed as a reference to a closed set of conditions. For example, an exemplary step that is described as “based on condition A” may be based on both a condition A and a condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase “based on” shall be construed in the same manner as the phrase “based at least in part on. ”

In the appended figures, similar components or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If just the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label, or other subsequent reference label.

The description set forth herein, in connection with the appended drawings, describes example configurations and does not represent all the examples that may be implemented or that are within the scope of the claims. The term “exemplary” used herein means “serving as an example, instance, or illustration, ” and not “preferred” or “advantageous over other examples. ” The detailed description includes specific details for the purpose of providing an understanding of the described techniques. These techniques, however, may be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form in order to avoid obscuring the concepts of the described examples.

The description herein is provided to enable a person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not limited to the examples and designs described herein, but is to be accorded the broadest scope consistent with the principles and novel features disclosed herein.

Claims

A method for wireless communications by a user equipment (UE) , comprising:

receiving a first stage uplink precoder indication of wideband uplink precoding;

receiving a second stage uplink precoder indication of a first wideband co-phase granularity for the wideband uplink precoding, a subband co-phase granularity for subband uplink precoding, or both, each of the first wideband co-phase granularity and the subband co-phase granularity being finer than a second wideband co-phase granularity indicated by the first stage uplink precoder indication;

generating precoded information based at least in part on the first stage uplink precoder indication and the second stage uplink precoder indication; and

transmitting a transmission generated based at least in part on the precoded information.
The method of claim 1, further comprising:

identifying a resource for transmitting the transmission.
The method of claim 2, wherein identifying the resource comprises:

receiving control signaling that configures the UE with the resource for transmitting the transmission.
The method of claim 2, further comprising:

receiving control signaling that comprises the first stage uplink precoder indication and the second stage uplink precoder indication.
The method of claim 2, further comprising:

receiving downlink control information that comprises the first stage uplink precoder indication and the second stage uplink precoder indication.
The method of claim 2, wherein receiving the first stage uplink precoder indication and the second stage uplink precoder indication comprises:

receiving first downlink control information that comprises the first stage uplink precoder indication and second downlink control information that comprises the second stage uplink precoder indication.
The method of claim 2, wherein receiving the first stage uplink precoder indication and the second stage uplink precoder indication comprises:

receiving a radio resource control configuration that comprises the first stage uplink precoder indication and downlink control information that comprises the second stage uplink precoder indication.
The method of claim 1, further comprising:

receiving downlink control information that schedules the UE to transmit the transmission.
The method of claim 8, wherein the downlink control information comprises the first stage uplink precoder indication and the second stage uplink precoder indication.
The method of claim 9, wherein the downlink control information comprises the first stage uplink precoder indication and second downlink control information comprises the second stage uplink precoder indication.
The method of claim 1, further comprising:

receiving control signaling that configures the UE with a group temporary identifier and a search offset; and

monitoring a search space for the second stage uplink precoder indication based at least in part on the group temporary identifier and the search offset.
The method of claim 11, wherein receiving the control signaling further comprises:

receiving the control signaling that configures the UE with a plurality of different second stage uplink precoder configurations;

decoding the search space to obtain downlink control information based at least in part on the group temporary identifier and the search offset; and

selecting a first configuration from the plurality of different second stage uplink precoder configurations based at least in part on the downlink control information, wherein the precoded information is generated based at least in part on the first configuration.
The method of claim 11, wherein receiving the control signaling further comprises:

receiving the control signaling that configures the UE with a plurality of different second stage uplink precoder configurations and a plurality of indexes respectively associated with the plurality of different second stage uplink precoder configurations;

decoding the search space to obtain downlink control information and a first index of the plurality of indexes based at least in part on the group temporary identifier and the search offset; and

selecting a first configuration from the plurality of different second stage uplink precoder configurations based at least in part on the downlink control information and the first index, wherein the precoded information is generated based at least in part on the first configuration.
The method of claim 1, further comprising:

identifying a payload size for a payload of the second stage uplink precoder indication, a minimum wideband co-phase indication granularity, a minimum subband co-phase indication granularity, and a number of subbands for frequency selective co-phase indication;

determining that the payload satisfies a co-phase indication granularity criterion based at least in part on the payload size, the number of subbands, and one or both of the minimum wideband co-phase indication granularity and the minimum subband co-phase indication granularity; and

applying a payload interpretation rule corresponding to the co-phase indication granularity criterion to interpret the payload of the second stage uplink precoder indication.
The method of claim 14, wherein determining that the payload satisfies the co-phase indication granularity criterion comprises:

applying, sequentially or in parallel, a respective co-phase indication granularity criterion of a plurality of different co-phase indication granularity criteria to determine that a first co-phase indication granularity criterion of the plurality of different co-phase indication granularity criteria is satisfied, wherein the first co-phase indication granularity criterion corresponds to the payload interpretation rule.
The method of claim 14, wherein the identifying further comprises:

identifying a set of parameters comprising one or more of the payload size for the payload of the second stage uplink precoder indication, the minimum wideband co-phase indication granularity, the minimum subband co-phase indication granularity, and the number of subbands for frequency selective co-phase indication, wherein the identifying is based at least in part on at least one predefinition for one or more parameters of the set of parameters stored in a storage device of the UE, receiving a RRC configuration indicating one or more parameters of the set of parameters, receiving downlink control information indicating one or more parameters of the set of parameters, or any combination thereof.
The method of claim 14, wherein the co-phase indication granularity criterion is that, using bits of the payload, the subband co-phase granularity at least satisfies the minimum subband co-phase indication granularity for each subband of a plurality of subbands, and wherein the payload interpretation rule is that the subband co-phase granularity for each subband of the plurality of subbands is indicated using respective bit subsets of the payload each having an equal number of bits that indicate a subband specific co-phase with equal co-phase granularity for each of the plurality of subbands.
The method of claim 14, wherein:

the co-phase indication granularity criterion is that, using bits of the payload, the subband co-phase granularity does not satisfy the minimum subband co-phase indication granularity, that, using the bits of the payload, the first wideband co-phase granularity at least satisfies the minimum wideband co-phase indication granularity, and that, apart from a subset of the bits of the payload used for indicating the first wideband co-phase granularity, remaining bits of the payload are capable of subband differential co-phase indication that satisfies the minimum subband co-phase indication granularity; and

wherein the payload interpretation rule is that a first bit subset of the payload indicates a wideband co-phase that satisfies the minimum wideband co-phase indication granularity and that the subband co-phase granularity for each subband of a plurality of subbands is differentially indicated relative to the wideband co-phase using respective bit subsets in a remainder of the payload, the subband co-phase granularity for each subband of the plurality of subbands having equal co-phase granularity.
The method of claim 14, wherein:

the co-phase indication granularity criterion is that, using bits of the payload, the first wideband co-phase granularity at least satisfies the minimum wideband co-phase indication granularity and that, apart from a subset of the bits of the payload used for indicating the first wideband co-phase granularity, remaining bits of the payload are not capable of subband differential co-phase indication that satisfies the minimum subband co-phase indication granularity; and

wherein the payload interpretation rule is that a first bit subset of the payload indicates a wideband co-phase that satisfies the minimum wideband co-phase indication granularity.
The method of claim 14, wherein:

the co-phase indication granularity criterion is that, using bits of the payload, the first wideband co-phase granularity at least satisfies the minimum wideband co-phase indication granularity and that, apart from a subset of the bits of the payload used for indicating the first wideband co-phase granularity, remaining bits of the payload are not capable of subband differential co-phase indication that satisfies the minimum subband co-phase indication granularity; and

wherein the payload interpretation rule is that bits of the payload indicate a wideband co-phase for each antenna port pair that has a finer wideband co-phase granularity than the minimum wideband co-phase indication granularity.
The method of claim 20, wherein the finer wideband co-phase granularity maximizes wideband co-phase granularity corresponding to the payload size.
The method of claim 1, further comprising:

identifying a payload size for a payload of the second stage uplink precoder indication, a fixed wideband co-phase indication granularity, a fixed subband co-phase indication granularity, and a number of subbands for frequency selective co-phase indication;

determining that the payload satisfies a co-phase indication granularity criterion based at least in part on the payload size, the number of subbands, and one or both of the fixed wideband co-phase indication granularity and the fixed subband co-phase indication granularity; and

applying a payload interpretation rule corresponding to the co-phase indication granularity criterion to interpret the payload of the second stage uplink precoder indication.
The method of claim 1, wherein the second stage uplink precoder indication indicates the first wideband co-phase granularity for at least one antenna port pair of a plurality of antenna ports, wherein the transmission is transmitted using the plurality of antenna ports.
The method of claim 1, wherein the second stage uplink precoder indication indicates the subband co-phase granularity for at least one antenna port pair of a plurality of antenna ports, wherein the transmission is transmitted using the plurality of antenna ports.
The method of claim 1, wherein transmitting the transmission comprises:

transmitting the transmission in a physical uplink shared channel.
The method of claim 1, wherein the transmission is a non-configured grant transmission or a configured grant transmission.
The method of claim 1, wherein the first stage uplink precoder indication is an uplink precoding matrix indicator.
A method for wireless communications by a base station, comprising:

transmitting a first stage uplink precoder indication of wideband precoding;

transmitting a second stage uplink precoder indication of a first wideband co-phase granularity for the wideband precoding, a subband co-phase granularity for subband uplink precoding, or both, each of the first wideband co-phase granularity and the subband co-phase granularity being finer than a second wideband co-phase granularity indicated by the first stage uplink precoder indication; and

monitoring for a signal generated based at least in part on information precoded in accordance with the first stage uplink precoder indication and the second stage uplink precoder indication.
An apparatus for wireless communications by a user equipment (UE) , comprising:

a processor,

memory in electronic communication with the processor; and

instructions stored in the memory and executable by the processor to cause the apparatus to:

receive a first stage uplink precoder indication of wideband uplink precoding;

receive a second stage uplink precoder indication of a first wideband co-phase granularity for the wideband uplink precoding, a subband co-phase granularity for subband uplink precoding, or both, each of the first wideband co-phase granularity and the subband co-phase granularity being finer than a second wideband co-phase granularity indicated by the first stage uplink precoder indication;

generate precoded information based at least in part on the first stage uplink precoder indication and the second stage uplink precoder indication; and

transmit a transmission generated based at least in part on the precoded information.
An apparatus for wireless communications by a base station, comprising:

a processor,

memory in electronic communication with the processor; and

instructions stored in the memory and executable by the processor to cause the apparatus to:

transmit a first stage uplink precoder indication of wideband precoding;

transmit a second stage uplink precoder indication of a first wideband co-phase granularity for the wideband precoding, a subband co-phase granularity for subband uplink precoding, or both, each of the first wideband co-phase granularity and the subband co-phase granularity being finer than a second wideband co-phase granularity indicated by the first stage uplink precoder indication; and

monitor for a signal generated based at least in part on information precoded in accordance with the first stage uplink precoder indication and the second stage uplink precoder indication.