WO2019241929A1

WO2019241929A1 - Downlink control indicator design for multi-port transmission

Info

Publication number: WO2019241929A1
Application number: PCT/CN2018/091986
Authority: WO
Inventors: Qiaoyu Li; Yu Zhang; Liangming WU; Chenxi HAO; Hao Xu
Original assignee: Qualcomm Incorporated
Priority date: 2018-06-20
Filing date: 2018-06-20
Publication date: 2019-12-26

Abstract

Certain aspects of the present disclosure provide techniques for adapting a transmission for a plurality of antenna ports by determining by a base station a number of available bits in a downlink control information (DCI) for indicating uplink precoding information for each of a number of groups of antenna ports of a user equipment. The techniques further include indicating the uplink precoding information based on the number of scheduled uplink sub-bands and according to a sub-band indication requirement, using the available bits in DCI for uplink precoding information indication. The techniques further include transmitting the DCI to the user equipment by the base station, and receiving by the base station, a data stream from the user equipment on the number of groups of antenna ports. The techniques further include decoding, by the base station the data stream based at least in part on the uplink precoding information in the DCI.

Description

DOWNLINK CONTROL INDICATOR DESIGN FOR MULTI-PORT TRANSMISSION

INTRODUCTION

Field of the Disclosure

Aspects of the present disclosure relate to wireless communications, and more particularly, to techniques for improved downlink control information (DCI) design for multi-port transmission on a group of antenna ports, and more particularly, for sub-band indications and a wide-band indication.

Description of Related Art

Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, broadcasts, etc. These wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc. ) . Examples of such multiple-access systems include 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) systems, LTE Advanced (LTE-A) systems, code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems, to name a few.

In some examples, a wireless multiple-access communication system may include a number of base stations (BSs) , which are each capable of simultaneously supporting communication for multiple communication devices, otherwise known as user equipments (UEs) . In an LTE or LTE-A network, a set of one or more base stations may define an eNodeB (eNB) . In other examples (e.g., in a next generation, a new radio (NR) , or 5G network) , a wireless multiple access communication system may include a number of distributed units (DUs) (e.g., edge units (EUs) , edge nodes (ENs) , radio heads (RHs) , smart radio heads (SRHs) , transmission reception points (TRPs) , etc. ) in communication with a number of central units (CUs) (e.g., central nodes (CNs) , access node controllers (ANCs) , etc. ) , where a set of one or more distributed units, in communication with a central unit, may define an access node (e.g., which may be referred to as a base station, 5G NB, next generation NodeB (gNB or gNodeB) , TRP, etc. ) . A base station or distributed unit may communicate with a set of UEs on downlink channels (e.g., for transmissions from a base station or to a UE) and uplink channels (e.g., for transmissions from a UE to a base station or distributed unit) .

These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. New Radio (NR) (e.g., 5G) is an example of an emerging telecommunication standard. NR is a set of enhancements to the LTE mobile standard promulgated by 3GPP. It is designed to better support mobile broadband Internet access by improving spectral efficiency, lowering costs, improving services, making use of new spectrum, and better integrating with other open standards using OFDMA with a cyclic prefix (CP) on the downlink (DL) and on the uplink (UL) . To these ends, NR supports beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation.

However, as the demand for mobile broadband access continues to increase, there exists a need for further improvements in NR and LTE technology. Preferably, these improvements should be applicable to other multi-access technologies and the telecommunication standards that employ these technologies.

BRIEF SUMMARY

The systems, methods, and devices of the disclosure each have several aspects, no single one of which is solely responsible for its desirable attributes. Without limiting the scope of this disclosure as expressed by the claims which follow, some features will now be discussed briefly. After considering this discussion, and particularly after reading the section entitled “Detailed Description” one will understand how the features of this disclosure provide advantages that include improved communications between access points and stations in a wireless network.

Certain aspects provide a method for wireless communication. The method generally includes adapting a transmission for a plurality of antenna ports. The method further includes determining by a base station a number of available bits in a downlink control information (DCI) for indicating uplink precoding information for each of a number of groups of antenna ports of a user equipment, wherein the uplink precoding information applies to a wide-band comprising a plurality of sub-bands. The method further includes indicating the uplink precoding information based on the number of scheduled uplink sub-bands and according to a sub-band indication requirement using the available bits in DCI for uplink precoding information indication. The method further includes determining if the number of available bits is sufficient to indicate sub-band indications for each of the plurality of sub-bands according to a sub-band indication requirement. The method further includes transmitting the DCI to the user equipment. The method further includes receiving by the base station, a data stream from the user equipment on the number of groups of antenna ports. The method further includes decoding, by the base station the data stream based at least in part on the uplink precoding information.

To the accomplishment of the foregoing and related ends, the one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and the appended drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of various aspects may be employed.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above-recited features of the present disclosure can be understood in detail, a more particular description, briefly summarized above, may be had by reference to aspects, some of which are illustrated in the drawings. It is to be noted, however, that the appended drawings illustrate only certain typical aspects of this disclosure and are therefore not to be considered limiting of its scope, for the description may admit to other equally effective aspects.

FIG. 1 is a block diagram conceptually illustrating an example telecommunications system, in accordance with certain aspects of the present disclosure.

FIG. 2 is a block diagram illustrating an example logical architecture of a distributed radio access network (RAN) , in accordance with certain aspects of the present disclosure.

FIG. 3 is a diagram illustrating an example physical architecture of a distributed RAN, in accordance with certain aspects of the present disclosure.

FIG. 4 is a block diagram conceptually illustrating a design of an example base station (BS) and user equipment (UE) , in accordance with certain aspects of the present disclosure.

FIG. 5 is a diagram showing examples for implementing a communication protocol stack, in accordance with certain aspects of the present disclosure.

FIG. 6 illustrates an example of a frame format for a new radio (NR) system, in accordance with certain aspects of the present disclosure.

FIG. 7 is a block diagram illustrating an example telecommunications system, in accordance with certain aspects of the present disclosure.

FIG. 8 is a flow chart depicting a method of adapting a transmission for a plurality of antenna ports using sub-band and wide-band indications in accordance with certain aspects of the present disclosure.

FIG. 9 illustrates a communications device that may include various components configured to perform operations for the techniques disclosed herein in accordance with aspects of the present disclosure.

To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one aspect may be beneficially utilized on other aspects without specific recitation.

DETAILED DESCRIPTION

Aspects of the present disclosure provide apparatus, methods, processing systems, and computer readable mediums for improved downlink control information (DCI) design for multi-port transmission on a group of antenna ports, and more particularly, for sub-band and wide-band indications in accordance with certain aspects of the present disclosure. In certain aspects, the sub-band indications and wide-band indication may refer to sub-band co-phase indications and a wide-band co-phase indication, respectively. In certain aspects, the sub-band indications and wide-band indication may refer to sub-band index of uplink precoding information and number of layers indications, and a wide-band index of uplink precoding information and number of layers indication. In certain aspects, an index of uplink precoding information and number of layers may refer to a transmit precoding matrix index (TPMI) .

As will be discussed herein, a UE and/or BS can include one or more antennas. For example, a UE and/or BS can include one or more physical antennas. These one or more physical antennas are to be distinguished from the term antenna port, used herein. In particular, an antenna port does not necessarily correspond to a physical antenna, but instead refers to a logical entity corresponding to particular one or more reference signal sequences. For example, multiple antenna port signals (e.g., corresponding to reference signal sequences) may be transmitted on a single physical antenna. In another example, a single antenna port signal may be transmitted on multiple physical antennas. In certain aspects, the term antenna port as used herein conforms to the definition of antenna port according to 3GPP TS 36.211.

Further, in certain aspects, the term “panel” may be used herein as referring to a group of antenna ports. In certain aspects, a group of antenna ports may include a single antenna port or multiple antenna ports. A group of antenna ports may or may not have the capability of coherent combining together with another group of antenna ports. If such coherent capability is enabled, two (e.g., or more) groups of antenna ports can together carry out coherent transmission.

The following description provides examples, and is not limiting of the scope, applicability, or examples set forth in the claims. Changes may be made in the function and arrangement of elements discussed without departing from the scope of the disclosure. Various examples may omit, substitute, or add various procedures or components as appropriate. For instance, the methods described may be performed in an order different from that described, and various steps may be added, omitted, or combined. Also, features described with respect to some examples may be combined in some other examples. For example, an apparatus may be implemented or a method may be practiced using any number of the aspects set forth herein. In addition, the scope of the disclosure is intended to cover such an apparatus or method which is practiced using other structure, functionality, or structure and functionality in addition to, or other than, the various aspects of the disclosure set forth herein. It should be understood that any aspect of the disclosure disclosed herein may be embodied by one or more elements of a claim. The word “exemplary” is used herein to mean “serving as an example, instance, or illustration. ” Any aspect described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects.

The techniques described herein may be used for various wireless communication technologies, such as LTE, CDMA, TDMA, FDMA, OFDMA, SC-FDMA and other networks. The terms “network” and “system” are often used interchangeably. A CDMA network may implement a radio technology such as Universal Terrestrial Radio Access (UTRA) , cdma2000, etc. UTRA includes Wide-band CDMA (WCDMA) and other variants of CDMA. cdma2000 covers IS-2000, IS-95 and IS-856 standards. A TDMA network may implement a radio technology such as Global System for Mobile Communications (GSM) . An OFDMA network may implement a radio technology such as NR (e.g. 5G RA) , Evolved UTRA (E-UTRA) , Ultra Mobile Broadband (UMB) , IEEE 802.11 (Wi-Fi) , IEEE 802.16 (WiMAX) , IEEE 802.20, Flash-OFDMA, etc. UTRA and E-UTRA are part of Universal Mobile Telecommunication System (UMTS) .

New Radio (NR) is an emerging wireless communications technology under development in conjunction with the 5G Technology Forum (5GTF) . 3GPP Long Term Evolution (LTE) and LTE-Advanced (LTE-A) are releases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A and GSM are described in documents from an 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 wireless networks and radio technologies mentioned above as well as other wireless networks and radio technologies. For clarity, while aspects may be described herein using terminology commonly associated with 3G and/or 4G wireless technologies, aspects of the present disclosure can be applied in other generation-based communication systems, such as 5G and later, including NR technologies.

New radio (NR) access (e.g., 5G technology) may support various wireless communication services, such as enhanced mobile broadband (eMBB) targeting wide bandwidth (e.g., 80 MHz or beyond) , millimeter wave (mmW) targeting high carrier frequency (e.g., 25 GHz or beyond) , massive machine type communications MTC (mMTC) targeting non-backward compatible MTC techniques, and/or mission critical targeting ultra-reliable low-latency communications (URLLC) . These services may include latency and reliability requirements. These services may also have different transmission time intervals (TTI) to meet respective quality of service (QoS) requirements. In addition, these services may co-exist in the same subframe.

Example Wireless Communications System

FIG. 1 illustrates an example wireless communication network 100 in which aspects of the present disclosure may be performed. For example, the wireless communication network 100 may be a New Radio (NR) or 5G network.

As illustrated in FIG. 1, the wireless network 100 may include a number of base stations (BSs) 110 and other network entities. A BS may be a station that communicates with user equipments (UEs) . Each BS 110 may provide communication coverage for a particular geographic area. In 3GPP, the term “cell” can refer to a coverage area of a Node B (NB) and/or a Node B subsystem serving this coverage area, depending on the context in which the term is used. In NR systems, the term “cell” and next generation NodeB (gNB) , new radio base station (NR BS) , 5G NB, access point (AP) , or transmission reception point (TRP) may be interchangeable. In some examples, a cell may not necessarily be stationary, and the geographic area of the cell may move according to the location of a mobile BS. In some examples, the base stations may be interconnected to one another and/or to one or more other base stations or network nodes (not shown) in wireless communication network 100 through various types of backhaul interfaces, such as a direct physical connection, a wireless connection, a virtual network, or the like using any suitable transport network.

In general, any number of wireless networks may be deployed in a given geographic area. Each wireless network may support a particular radio access technology (RAT) and may operate on one or more frequencies. A RAT may also be referred to as a radio technology, an air interface, etc. A frequency may also be referred to as a carrier, a subcarrier, a frequency channel, a tone, a sub-band, etc. Each frequency may support a single RAT in a given geographic area in order to avoid interference between wireless networks of different RATs. In some cases, NR or 5G RAT networks may be deployed.

A base station (BS) may provide communication coverage for a macro cell, a pico cell, a femto cell, and/or other types of cells. A macro cell may cover a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscription. A pico cell may cover a relatively small geographic area and may allow unrestricted access by UEs with service subscription. A femto cell may cover a relatively small geographic area (e.g., a home) and may allow 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, etc. ) . A BS for a macro cell may be referred to as a macro BS. A BS for a pico cell may be referred to as a pico BS. A BS for a femto cell may be referred to as a femto BS or a home BS. In the example shown in FIG. 1, the

BSs

110a, 110b and 110c may be macro BSs for the

macro cells

102a, 102b and 102c, respectively. The BS 110x may be a pico BS for a pico cell 102x. The BSs 110y and 110z may be femto BSs for the

femto cells

102y and 102z, respectively. A BS may support one or multiple (e.g., three) cells.

Wireless communication network 100 may also include relay stations. A relay station is a station that receives a transmission of data and/or other information from an upstream station (e.g., a BS or a UE) and sends a transmission of the data and/or other information to a downstream station (e.g., a UE or a BS) . A relay station may also be a UE that relays transmissions for other UEs. In the example shown in FIG. 1, a relay station 110r may communicate with the BS 110a and a UE 120r in order to facilitate communication between the BS 110a and the UE 120r. A relay station may also be referred to as a relay BS, a relay, etc.

Wireless network 100 may be a heterogeneous network that includes BSs of different types, e.g., macro BS, pico BS, femto BS, relays, etc. These different types of BSs may have different transmit power levels, different coverage areas, and different impact on interference in the wireless network 100. For example, macro BS may have a high transmit power level (e.g., 20 Watts) whereas pico BS, femto BS, and relays may have a lower transmit power level (e.g., 1 Watt) .

Wireless communication network 100 may support synchronous or asynchronous operation. For synchronous operation, the BSs may have similar frame timing, and transmissions from different BSs may be approximately aligned in time. For asynchronous operation, the BSs may have different frame timing, and transmissions from different BSs may not be aligned in time. The techniques described herein may be used for both synchronous and asynchronous operation.

A network controller 130 may couple to a set of BSs and provide coordination and control for these BSs. The network controller 130 may communicate with the BSs 110 via a backhaul. The BSs 110 may also communicate with one another (e.g., directly or indirectly) via wireless or wireline backhaul.

The UEs 120 (e.g., 120x, 120y, etc. ) may be dispersed throughout the wireless network 100, and each UE may be stationary or mobile. A UE may also be referred to as a mobile station, a terminal, an access terminal, a subscriber unit, a station, a Customer Premises Equipment (CPE) , a cellular phone, a smart phone, a personal digital assistant (PDA) , a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a tablet computer, a camera, a gaming device, a netbook, a smartbook, an ultrabook, an appliance, a medical device or medical equipment, a biometric sensor/device, a wearable device such as a smart watch, smart clothing, smart glasses, a smart wrist band, smart jewelry (e.g., a smart ring, a smart bracelet, etc. ) , an entertainment device (e.g., a music device, a video device, a satellite radio, etc. ) , a vehicular component or sensor, a smart meter/sensor, industrial manufacturing equipment, a global positioning system device, or any other suitable device that is configured to communicate via a wireless or wired medium. Some UEs may be considered machine-type communication (MTC) devices or evolved MTC (eMTC) devices. MTC and eMTC UEs include, for example, robots, drones, remote devices, sensors, meters, monitors, location tags, etc., that may communicate with a BS, another device (e.g., remote device) , or some other entity. A wireless node may provide, for example, connectivity for or to a network (e.g., a wide area network such as Internet or a cellular network) via a wired or wireless communication link. Some UEs may be considered Internet-of-Things (IoT) devices, which may be narrowband IoT (NB-IoT) devices.

Certain wireless networks (e.g., LTE) utilize orthogonal frequency division multiplexing (OFDM) on the downlink and single-carrier frequency division multiplexing (SC-FDM) on the uplink. OFDM and SC-FDM partition the system bandwidth into multiple (K) orthogonal subcarriers, which are also commonly referred to as tones, bins, etc. Each subcarrier may be modulated with data. In general, modulation symbols are sent in the frequency domain with OFDM and in the time domain with SC-FDM. The spacing between adjacent subcarriers may be fixed, and the total number of subcarriers (K) may be dependent on the system bandwidth. For example, the spacing of the subcarriers may be 15 kHz and the minimum resource allocation (called a “resource block” (RB) ) may be 12 subcarriers (or 180 kHz) . Consequently, the nominal Fast Fourier Transfer (FFT) size may be equal to 128, 256, 512, 1024 or 2048 for system bandwidth of 1.25, 2.5, 5, 10, or 20 megahertz (MHz) , respectively. The system bandwidth may also be partitioned into sub-bands. For example, a sub-band may cover 1.08 MHz (e.g., 6 resource blocks) , and there may be 1, 2, 4, 8, or 16 sub-bands for system bandwidth of 1.25, 2.5, 5, 10 or 20 MHz, respectively.

While aspects of the examples described herein may be associated with LTE technologies, aspects of the present disclosure may be applicable with other wireless communications systems, such as NR. NR may utilize OFDM with a CP on the uplink and downlink and include support for half-duplex operation using TDD. Beamforming may be supported and beam direction may be dynamically configured. MIMO transmissions with precoding may also be supported. MIMO configurations in the DL may support up to 8 transmit antennas with multi-layer DL transmissions up to 8 streams and up to 2 streams per UE. Multi-layer transmissions with up to 2 streams per UE may be supported. Aggregation of multiple cells may be supported with up to 8 serving cells.

In some examples, access to the air interface may be scheduled, wherein a. A scheduling entity (e.g., a base station) allocates resources for communication among some or all devices and equipment within its service area or cell. The scheduling entity may be responsible for scheduling, assigning, reconfiguring, and releasing resources for one or more subordinate entities. That is, for scheduled communication, subordinate entities utilize resources allocated by the scheduling entity. Base stations are not the only entities that may function as a scheduling entity. In some examples, a UE may function as a scheduling entity and may schedule resources for one or more subordinate entities (e.g., one or more other UEs) , and the other UEs may utilize the resources scheduled by the UE for wireless communication. In some examples, a UE may function as a scheduling entity in a peer-to-peer (P2P) network, and/or in a mesh network. In a mesh network example, UEs may communicate directly with one another in addition to communicating with a scheduling entity.

In FIG. 1, a solid line with double arrows indicates desired transmissions between a UE and a serving BS, which is a BS designated to serve the UE on the downlink and/or uplink. A finely dashed line with double arrows indicates interfering transmissions between a UE and a BS.

FIG. 2 illustrates an example logical architecture of a distributed Radio Access Network (RAN) 200, which may be implemented in the wireless communication network 100 illustrated in FIG. 1. A 5G access node 206 may include an access node controller (ANC) 202. ANC 202 may be a central unit (CU) of the distributed RAN 200. The backhaul interface to the Next Generation Core Network (NG-CN) 204 may terminate at ANC 202. The backhaul interface to neighboring next generation access Nodes (NG-ANs) 210 may terminate at ANC 202. ANC 202 may include one or more transmission reception points (TRPs) 208 (e.g., cells, BSs, gNBs, etc. ) .

The TRPs 208 may be a distributed unit (DU) . TRPs 208 may be connected to a single ANC (e.g., ANC 202) or more than one ANC (not illustrated) . For example, for RAN sharing, radio as a service (RaaS) , and service specific AND deployments, TRPs 208 may be connected to more than one ANC. TRPs 208 may each include one or more antenna ports. TRPs 208 may be configured to individually (e.g., dynamic selection) or jointly (e.g., joint transmission) serve traffic to a UE.

The logical architecture of distributed RAN 200 may support fronthauling solutions across different deployment types. For example, the logical architecture may be based on transmit network capabilities (e.g., bandwidth, latency, and/or jitter) .

The logical architecture of distributed RAN 200 may share features and/or components with LTE. For example, next generation access node (NG-AN) 210 may support dual connectivity with NR and may share a common fronthaul for LTE and NR.

The logical architecture of distributed RAN 200 may enable cooperation between and among TRPs 208, for example, within a TRP and/or across TRPs via ANC 202. An inter-TRP interface may not be used.

Logical functions may be dynamically distributed in the logical architecture of distributed RAN 200. As will be described in more detail with reference to FIG. 5, the Radio Resource Control (RRC) layer, Packet Data Convergence Protocol (PDCP) layer, Radio Link Control (RLC) layer, Medium Access Control (MAC) layer, and a Physical (PHY) layers may be adaptably placed at the DU (e.g., TRP 208) or CU (e.g., ANC 202) .

FIG. 3 illustrates an example physical architecture of a distributed Radio Access Network (RAN) 300, according to aspects of the present disclosure. A centralized core network unit (C-CU) 302 may host core network functions. C-CU 302 may be centrally deployed. C-CU 302 functionality may be offloaded (e.g., to advanced wireless services (AWS) ) , in an effort to handle peak capacity.

A centralized RAN unit (C-RU) 304 may host one or more ANC functions. Optionally, the C-RU 304 may host core network functions locally. The C-RU 304 may have distributed deployment. The C-RU 304 may be close to the network edge.

A DU 306 may host one or more TRPs (Edge Node (EN) , an Edge Unit (EU) , a Radio Head (RH) , a Smart Radio Head (SRH) , or the like) . The DU may be located at edges of the network with radio frequency (RF) functionality.

FIG. 4 illustrates example components of BS 110 and UE 120 (as depicted in FIG. 1) , which may be used to implement aspects of the present disclosure. For example, antennas 452,

processors

466, 458, 464, and/or controller/processor 480 of the UE 120 and/or antennas 434,

processors

420, 460, 438, and/or controller/processor 440 of the BS 110 may be used to perform the various techniques and methods described herein.

At the BS 110, a transmit processor 420 may receive data from a data source 412 and control information from a controller/processor 440. The control information may be for the physical broadcast channel (PBCH) , physical control format indicator channel (PCFICH) , physical hybrid ARQ indicator channel (PHICH) , physical downlink control channel (PDCCH) , group common PDCCH (GC PDCCH) , etc. The data may be for the physical downlink shared channel (PDSCH) , etc. The processor 420 may process (e.g., encode and symbol map) the data and control information to obtain data symbols and control symbols, respectively. The processor 420 may also generate reference symbols, e.g., for the primary synchronization signal (PSS) , secondary synchronization signal (SSS) , and cell-specific reference signal (CRS) . A transmit (TX) multiple-input multiple-output (MIMO) processor 430 may perform spatial processing (e.g., precoding) on the data symbols, the control symbols, and/or the reference symbols, if applicable, and may provide output symbol streams to the modulators (MODs) 432a through 432t. Each modulator 432 may process a respective output symbol stream (e.g., for OFDM, etc. ) to obtain an output sample stream. Each modulator may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. Downlink signals from modulators 432a through 432t may be transmitted via the antennas 434a through 434t, respectively.

At the UE 120, the antennas 452a through 452r may receive the downlink signals from the base station 110 and may provide received signals to the demodulators (DEMODs) in transceivers 454a through 454r, respectively. Each demodulator 454 may condition (e.g., filter, amplify, downconvert, and digitize) a respective received signal to obtain input samples. Each demodulator may further process the input samples (e.g., for OFDM, etc. ) to obtain received symbols. A MIMO detector 456 may obtain received symbols from all the demodulators 454a through 454r, perform MIMO detection on the received symbols if applicable, and provide detected symbols. A receive processor 458 may process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded data for the UE 120 to a data sink 460, and provide decoded control information to a controller/processor 480.

On the uplink, at UE 120, a transmit processor 464 may receive and process data (e.g., for the physical uplink shared channel (PUSCH) ) from a data source 462 and control information (e.g., for the physical uplink control channel (PUCCH) from the controller/processor 480. The transmit processor 464 may also generate reference symbols for a reference signal (e.g., for the sounding reference signal (SRS) ) . The symbols from the transmit processor 464 may be precoded by a TX MIMO processor 466 if applicable, further processed by the demodulators in transceivers 454a through 454r (e.g., for SC-FDM, etc. ) , and transmitted to the base station 110. At the BS 110, the uplink signals from the UE 120 may be received by the antennas 434, processed by the modulators 432, detected by a MIMO detector 436 if applicable, and further processed by a receive processor 438 to obtain decoded data and control information sent by the UE 120. The receive processor 438 may provide the decoded data to a data sink 439 and the decoded control information to the controller/processor 440.

The controllers/

processors

440 and 480 may direct the operation at the base station 110 and the UE 120, respectively. The processor 440 and/or other processors and modules at the BS 110 may perform or direct the execution of processes for the techniques described herein. The

memories

442 and 482 may store data and program codes for BS 110 and UE 120, respectively. A scheduler 444 may schedule UEs for data transmission on the downlink and/or uplink.

FIG. 5 illustrates a diagram 500 showing examples for implementing a communications protocol stack, according to aspects of the present disclosure. The illustrated communications protocol stacks may be implemented by devices operating in a wireless communication system, such as a 5G system (e.g., a system that supports uplink-based mobility) . Diagram 500 illustrates a communications protocol stack including a Radio Resource Control (RRC) layer 510, a Packet Data Convergence Protocol (PDCP) layer 515, a Radio Link Control (RLC) layer 520, a Medium Access Control (MAC) layer 525, and a Physical (PHY) layer 530. In various examples, the layers of a protocol stack may be implemented as separate modules of software, portions of a processor or ASIC, portions of non-collocated devices connected by a communications link, or various combinations thereof. Collocated and non-collocated implementations may be used, for example, in a protocol stack for a network access device (e.g., ANs, CUs, and/or DUs) or a UE.

A first option 505-a shows a split implementation of a protocol stack, in which implementation of the protocol stack is split between a centralized network access device (e.g., an ANC 202 in FIG. 2) and distributed network access device (e.g., DU 208 in FIG. 2) . In the first option 505-a, an RRC layer 510 and a PDCP layer 515 may be implemented by the central unit, and an RLC layer 520, a MAC layer 525, and a PHY layer 530 may be implemented by the DU. In various examples the CU and the DU may be collocated or non-collocated. The first option 505-a may be useful in a macro cell, micro cell, or pico cell deployment.

A second option 505-b shows a unified implementation of a protocol stack, in which the protocol stack is implemented in a single network access device. In the second option, RRC layer 510, PDCP layer 515, RLC layer 520, MAC layer 525, and PHY layer 530 may each be implemented by the AN. The second option 505-b may be useful in, for example, a femto cell deployment.

Regardless of whether a network access device implements part or all of a protocol stack, a UE may implement an entire protocol stack as shown in 505-c (e.g., the RRC layer 510, the PDCP layer 515, the RLC layer 520, the MAC layer 525, and the PHY layer 530) .

In LTE, the basic transmission time interval (TTI) or packet duration is the 1 ms subframe. In NR, a subframe is still 1 ms, but the basic TTI is referred to as a slot. A subframe contains a variable number of slots (e.g., 1, 2, 4, 8, 16, …slots) depending on the subcarrier spacing. The NR RB is 12 consecutive frequency subcarriers. NR may support a base subcarrier spacing of 15 KHz and other subcarrier spacing may be defined with respect to the base subcarrier spacing, for example, 30 kHz, 60 kHz, 120 kHz, 240 kHz, etc. The symbol and slot lengths scale with the subcarrier spacing. The CP length also depends on the subcarrier spacing.

FIG. 6 is a diagram showing an example of a frame format 600 for NR. The transmission timeline for each of the downlink and uplink may be partitioned into units of radio frames. Each radio frame may have a predetermined duration (e.g., 10 ms) and may be partitioned into 10 subframes, each of 1 ms, with indices of 0 through 9. Each subframe may include a variable number of slots depending on the subcarrier spacing. Each slot may include a variable number of symbol periods (e.g., 7 or 14 symbols) depending on the subcarrier spacing. The symbol periods in each slot may be assigned indices. A mini-slot, which may be referred to as a sub-slot structure, refers to a transmit time interval having a duration less than a slot (e.g., 2, 3, or 4 symbols) .

Each symbol in a slot may indicate a link direction (e.g., DL, UL, or flexible) for data transmission and the link direction for each subframe may be dynamically switched. The link directions may be based on the slot format. Each slot may include DL/UL data as well as DL/UL control information.

In NR, a synchronization signal (SS) block is transmitted. The SS block includes a PSS, a SSS, and a two symbol PBCH. The SS block can be transmitted in a fixed slot location, such as the symbols 0-3 as shown in FIG. 6. The PSS and SSS may be used by UEs for cell search and acquisition. The PSS may provide half-frame timing, the SS may provide the CP length and frame timing. The PSS and SSS may provide the cell identity. The PBCH carries some basic system information, such as downlink system bandwidth, timing information within radio frame, SS burst set periodicity, system frame number, etc. The SS blocks may be organized into SS bursts to support beam sweeping. Further system information such as, remaining minimum system information (RMSI) , system information blocks (SIBs) , other system information (OSI) can be transmitted on a physical downlink shared channel (PDSCH) in certain subframes.

In some circumstances, two or more subordinate entities (e.g., UEs) may communicate with each other using sidelink signals. Real-world applications of such sidelink communications may include public safety, proximity services, UE-to-network relaying, vehicle-to-vehicle (V2V) communications, Internet of Everything (IoE) communications, IoT communications, mission-critical mesh, and/or various other suitable applications. Generally, a sidelink signal may refer to a signal communicated from one subordinate entity (e.g., UE1) to another subordinate entity (e.g., UE2) without relaying that communication through the scheduling entity (e.g., UE or BS) , even though the scheduling entity may be utilized for scheduling and/or control purposes. In some examples, the sidelink signals may be communicated using a licensed spectrum (unlike wireless local area networks, which typically use an unlicensed spectrum) .

A UE may operate in various radio resource configurations, including a configuration associated with transmitting pilots using a dedicated set of resources (e.g., a radio resource control (RRC) dedicated state, etc. ) or a configuration associated with transmitting pilots using a common set of resources (e.g., an RRC common state, etc. ) . When operating in the RRC dedicated state, the UE may select a dedicated set of resources for transmitting a pilot signal to a network. When operating in the RRC common state, the UE may select a common set of resources for transmitting a pilot signal to the network. In either case, a pilot signal transmitted by the UE may be received by one or more network access devices, such as an AN, or a DU, or portions thereof. Each receiving network access device may be configured to receive and measure pilot signals transmitted on the common set of resources, and also receive and measure pilot signals transmitted on dedicated sets of resources allocated to the UEs for which the network access device is a member of a monitoring set of network access devices for the UE. One or more of the receiving network access devices, or a CU to which receiving network access device (s) transmit the measurements of the pilot signals, may use the measurements to identify serving cells for the UEs, or to initiate a change of serving cell for one or more of the UEs.

Example Downlink Control Information (DCI) Design

Wireless communication systems continually have increasing needs for more reliable and higher data rate transmissions. As discussed above MIMO technology can facilitate higher data rates and provide improved wireless coverage, in some cases without the need to increase the average transmission power or the frequency bandwidth. MIMO technology is able to accomplish this by allowing multiple data streams and increased channel capacity.

In certain aspects to facilitate MIMO technology, a UE may send a rank indicator (RI) indicating the number layers supported by the current channel of the UE, a precoding matrix indicator PMI (e.g., from a codebook) , as well as the resulting channel quality indicator (CQI) reported by the UE to the base station after measuring a reference signal (e.g., a common reference signal (CRS) ) , to a base station to aid in precoding. A base station may also take into account other factors for precoding, such as the current bandwidth traffic and/or the location of other UEs and/or base stations. In other aspects, the base station may ignore information sent from the UE entirely and precoding is done according to other information at the base station.

A base station provides downlink control information (DCI) to one or more UEs on the physical downlink control channel (PDCCH) to one or more UEs. DCI provides information such as the resource locations (e.g., time, frequency, spatial) for use by one or more UEs for communication (e.g., on the UL/DL) and what modulation scheme should be used to code and decode data communicated on those resources. In certain aspects, DCI has additional information as set forth in the disclosure. In certain aspects, a base station transmits one or more DCIs in a single downlink or a plurality of DCIs in a plurality of downlinks.

DCI has evolved to include a plurality of DCI formats that are typically used to provide a UE with certain information. DCI Format 0 is used to indicate the resources for the UE for sending uplink data. DCI Format 1 is used for downlink resource allocation for Single Input Multiple Output (SIMO) transmissions. DCI Format 1A 1 is used for downlink resource allocation for SIMO transmissions and/or allocating a dedicated preamble signature to a UE for random access. DCI Format 1B is used for Multiple Input Multiple Output (MIMO) transmission control. DCI Format 1C is used for certain PDSCH assignments. DCI Format 1D is also used for MIMO transmission control and typically includes additional information related to power offset. DCI Format 2 and Format 2A are both used for transmission of the PDSCH resource allocation for closed and open loop MIMO operation, respectively. DCI Format 3 and Format 3A are used for the transmission of transit power control (TPC) command for an uplink channel. Format 4 is used for uplink assignment for uplink MIMO for up to 4 layers. It will be appreciated that there are additional DCI Formats, and certain aspects of the disclosure are not limited to a particular DCI Format, listed or unlisted.

DCI is typically contained in control channel elements (CCE) in a PDCCH transmission. Where 1 CCE, for example, includes 36 resource elements. It will be appreciated that the number of available resource elements can vary based on several factors, such as the number of OFDM symbols, bandwidth, and the number of groups of antenna ports to name a few. For example, if the total number of OFDM symbols is N=3, the total number of subcarriers in a resource block is S=12, and the total number of resource blocks for a 20 MHz bandwidth is 100, then there are N*S*100 = 3600 total REs. It will be appreciated that the number of REs available for DCI is less than the total 3600 RE in this case because a certain number of REs are allocated for other things (e.g., reference signals, Physical Hybrid-ARQ Indicator Channel (PHICH) , Physical Control Format Indicator (PCFICH) , etc. ) It will be appreciated that the number of bits in a RE can also vary based on modulation type. For example phase shift key (PSK) modulation has different types, such as BPSK containing one bit per RE, QPSK containing 2 bits per RE, 8PSK containing 3 bits per RE, etc.

The number of CCEs needed to send a DCI can also vary based on several factors, such as the DCI Format, number of UEs, and the number of antenna ports to name a few. Thus, for example, in a communication system using quadrant phase shifted (QPSK) modulation, 1 CCE that contains 36 REs, contains 72 bits per CCE because there are 2 bits per RE when using QPSK. Thus, if a DCI is 100 bits in size, it will not fit in 1 CCE of 72 bits. In this case, 2 CCEs should be used to include all 100 bits of the DCI in the 144 total bits of 2 the CCEs.

The number of CCEs used for sending control information (e.g., DCI) is commonly referred to as an aggregation level, with typical aggregation levels of 1, 2, 4 or 8 based on a PDCCH format of 0, 1, 2, or 3 respectively. It will be appreciated that in certain aspects, a base station my increase the aggregation level when the channel conditions are poor, thereby providing redundant information to the UE, which can increase the chances that one or more UEs can decode the PDCCH transmission. In certain aspects, the base station uses the size of a desired DCI and/or information from an uplink (e.g. a channel quality indicator (CQI) ) to determine an aggregation level.

In certain aspects, an index of uplink precoding information and number of layers indications, such as a TPMI, is included in a DCI in a downlink to one or more UEs. In certain aspects, an index of uplink precoding information and number of layers indication can include information that identifies the use of open loop (OL) or closed loop (CL) spatial multiplexing as well as the number of antenna ports (e.g. in DCI Format 2, the number of antenna ports used for closed loop spatial multiplexing can be specified (e.g., three bits for two transmit antenna ports, and six bits for four transmit antenna ports) as well as to determine whether the base station is using transmit diversity or open loop spatial multiplexing. ) In certain aspects, an index of uplink precoding information and number of layers indication may be referred to a TPMI. In certain aspects, a TPMI and an index of uplink precoding information and number of layers contain the same information, and in other aspects, they contain different information.

In certain aspects, using DCI Formats and/or an index of uplink precoding information and number of layers for uplink precoding is limited (e.g., limited to an inter-port co-phase granularity of

for up to 4 antenna ports) .

FIG. 7 depicts a wireless communication system 700 in accordance with certain aspects of the disclosure. Wireless communication system 700 includes

UE

710a and 710b (collectively UEs 710) and BS 750. Wireless communication system 700 may correspond to wireless communication network 100 of Fig. 1. UEs 710 may correspond to UEs 120 of Fig. 1. BS 750 may correspond to BS 110 of Fig. 1. UE 710a includes a group of antenna ports 720a, which in certain aspects may be a single antenna port. UE 710b includes a plurality of groups of antenna ports 720b-n, and BS 750 includes a plurality of groups of antenna ports 760a-n.

BS 750 is configured to send downlink control information DCI 770 in a downlink transmission 762 (e.g., a PDCCH transmission) to UEs 710. In certain aspects, DCI 770 contains a certain number of available bits for indicating uplink precoding information for each of a number of groups of antenna ports (e.g., 720a, and/or one or more of 720b-n in communication with one or more of 760a-n) . In certain aspects, DCI 770 indicates uplink precoding information based on the number of scheduled uplink sub-bands (e.g., uplink sub-bands associated with one or more of) and according to a sub-band indication, using the available bits in DCI for uplink precoding information.

In certain aspects, DCI 770 includes one or more of a “DCI Parameter” including a format 772, a modulation type 774 (e.g., BPSK, QPSK, 8PSK, etc. ) , an aggregation level 776 (e.g., 1, 2, 4, 8, etc. ) , a wide-band indication 780, sub-band indications 782, a bitmap 784 (e.g., a network implemented bitmap) comprising a bitmap and one or more sub-band differential indications (e.g., sub-band differential co-phase indications, or sub-band differential index of uplink precoding information and number of layers indications indications) , a selection pattern 786 (e.g., a network implemented selection pattern) comprising a selection pattern and one or more sub-band differential indications, and other information 788 (e.g., number of groups of antenna ports, etc. ) . It will be appreciated that a number of available bits in downlink transmission 762 for DCI 770 may be based in part on one or more of the DCI Parameters.

As discussed, the wide-band indication 780 may comprise a wide-band co-phase indication and/or wide-band index of uplink precoding information and number of layers indication that provides wide-band information (e.g., indications of co-phase and/or TPMI) for a number of groups of antenna ports. Further, the sub-band indications 780 may each comprise a sub-band co-phase indication and/or sub-band index of uplink precoding information and number of layers indication that provides sub-band information (e.g., indications of co-phase and/or index of uplink precoding information and number of layers indications) for a number of groups of antenna ports. A co-phase indication may comprise an indication of the co-phases for a number of groups of antenna ports (e.g., panels) (e.g., co-phases with respect to a first group of antenna ports) used for coherent transmission over a particular frequency band and may also be referred to as an inter-panel co-phase indication.

In certain aspects, as discussed, DCI 770 contains a number of available bits for uplink precoding information. In certain aspects, the number of available bits for uplink precoding information for each of a number of groups of antenna ports refers to the number of bits available for including co-phase indications and/or index of uplink precoding information and number of layers indications (e.g., wide-band indication 780 and/or sub-band indication 782) in DCI 770 corresponding to a number of groups of antenna ports. In certain aspects, a wide-band indication 780 for a number of groups of antenna ports corresponds to an indication for a plurality of sub-bands. Further, each sub-band indication 782 corresponds to an indication of one of the plurality of sub-bands. In certain aspects, if the number of available bits in DCI 770 is not sufficient to include sub-band indications 782 that meet a sub-band indication requirement (e.g., minimum granularity requirement, fixed granularity requirement, bit-width requirement) for each of the plurality of sub-bands, a wide-band indication 780 that meets a wide-band indication requirement (e.g., minimum granularity requirement, fixed granularity requirement, bit-width requirement) can be used to indicate information for the plurality of sub-bands. However, when the number of available bits in DCI 770 is sufficient to include individual sub-band indications 782 for each of the plurality of sub-bands, such sub-band indications 782 are included as then different information can be provided for different sub-bands.

For example, in certain aspects, one or more co-phase indications (e.g., sub-band co-phase indications and/or a wide-band co-phase indication) are included in DCI for the number of groups of antenna ports. Accordingly, (N _{Antenna Ports}-1) × N _co-phase bits of DCI 770 are used for co-phase indication, where N _{Antenna Ports}= a number of groups of antenna ports, and N _co-phase is the number of bits in DCI 770 for co-phase indication for a single group of antenna ports of the number of groups of antenna ports. Thus, the type of co-phase indication to include for the number of groups of antenna ports may be determined by the BS 750 such that (N _{Antenna Ports}-1) × N _co-phase is less than or equal to the number of available bits. Further, the maximum value for N _co-phase can be determined as floor [ (number of available bits) / (N _{Antenna Ports}-1) ] . Further references to N _co-phasein equations presented may refer to such a maximum value of N _co-phase.

In certain aspects, BS 750 can determine if the number of available bits in DCI 770 is sufficient to indicate separate sub-band co-phase indications (e.g., corresponding to sub-band indications 782) for each of the plurality of sub-bands (e.g., one or more sub-bands between UEs 710 and BS 750) using a flexible granularity approach. In certain aspects, BS 750 determines a sub-band co-phase indication granularity minimum requirement (e.g., N _sb-co-phase) (also referred to as a minimum granularity requirement for the sub-band co-phase indication) and a wide-band co-phase indication granularity minimum requirement (e.g., N _wb-co-phase) (also referred to as a minimum granularity requirement for the wide-band co-phase indication) . It will be appreciated that the wide-band co-phase indication granularity requirement is less precise than the sub-band co-phase indication granularity requirement, and that the configured number of sub-bands (N _sb) can vary. In certain aspects, the sub-band co-phase indication granularity minimum requirement and the wide-band co-phase indication granularity minimum requirement are based on the number of phases used for a phase shift keying (PSK) for modulating co-phase indications, also referred to as a PSK level. In certain aspects, N _sb-co-phaseand N _wb-co-phase refer to numbers of levels of granularity required, meaning log ₂ N _sb-co-phase and log ₂ N _wb-co-phase bits are required, respectively, to indicate information for the number of levels.

In certain aspects, BS 750 determines that a number of bits in the available bits is sufficient to indicate separate sub-band co-phase indications for each of the plurality of sub-bands according to the sub-band co-phase indication granularity minimum requirement (e.g.,

) . In this case, BS 750 uses the same number of bits Z (where

) for each sub-band co-phase indication for each sub-band in DCI 770, and preferably, BS 750 uses as many bits per sub-band as possible (e.g.,

) for equal granularity levels (e.g.,

) . In certain aspects, BS 750 includes the sub-band co-phase indications as sub-band indications 782 according to the sub-band co-phase indication granularity minimum requirement for each of the plurality of sub-bands as uplink precoding information in DCI 770.

In other aspects, BS 750 determines that the number of available bits is not sufficient to indicate separate sub-band co-phase indications for each of the plurality of sub-bands according to the sub-band co-phase indication granularity minimum requirement (e.g.,

) . In this case, BS 750 includes the wide-band co-phase indication as a wide-band indication 780 according to the wide-band co-phase indication granularity minimum requirement as corresponding to the plurality of sub-bands as uplink precoding information in DCI 770 (e.g., when the wide-band co-phase indication granularity minimum requirement is met (e.g., N _co-phase≥ log ₂ N _wb-co-phase) . For example, the number of bits used for the wide-band co-phase indication Y may be such that N _co-phase× (N _{Antenna Ports}-1) ≥ Y ≥log ₂ N _wb-co-phase× (N _{Antenna Ports}-1) .

It will be appreciated that in certain aspects, DCI 770 may contain remaining bits in the available bits after including wide-band co-phase indication (e.g., when N _co-phase× (N _{Antenna Ports}-1) ＞ Y) . In certain aspects BS 750 may use the remaining bits in the available bits in DCI 770 for sub-band differential co-phase indication. Sub-band differential co-phase indication may indicate a difference between the co-phase indicated in the wide-band, and the co-phase for a particular sub-band. In certain aspects, BS 750 can determine if a sub-band differential co-phase indication granularity minimum requirement is met (e.g.,

).If the sub-band differential co-phase indication granularity minimum requirement is met, BS 750 uses the same number of bits from the remaining bits in the available bits for each sub-band differential co-phase indication (e.g.,

) in DCI 770 in addition to wide-band co-phase indication in DCI 770, to indicate differential sub-band co-phase, such that each sub-band can be co-phase indicated with a differential co-phase of equal granularity (e.g.,

) .

In other aspects, BS 750 may determine that DCI 770 is incapable of containing sub-band differential co-phase indications that meet the sub-band co-phase indication granularity minimum requirement for each sub-band, meaning the sub-band differential co-phase indication granularity minimum requirement is not met (e.g.,

).In certain aspects, if the sub-band differential co-phase indication granularity minimum requirement is not met, BS 750 may decrease the sub-band differential co-phase granularity minimum requirement such that it is possible to include sub-band differential co-phase indications according to the sub-band differential co-phase indication granularity minimum requirement (corresponding to a type of sub-band differential indication requirement) based on the decreased sub-band differential co-phase granularity minimum requirement (e.g., by finding a minimum available integer G≥2 such that

).If BS 750 is unable to decrease the sub-band differential co-phase granularity minimum requirement (e.g., unable to find such an integer G) , meaning the number of remaining bits in the available bits after including the wide-band co-phase indication is not enough for any possible decreased sub-band differential co-phase granularity minimum requirement, then BS 750 may include no sub-band differential co-phase indications in DCI 770. In certain such aspects where BS 750 is unable to decrease the sub-band differential co-phase granularity minimum requirement BS 750 may use any remaining bits (e.g., all) in the available bits for the wide-band co-phase indication to provide a higher granularity of indication for the wide-band.

In certain aspects, BS 750 can determine if the number of available bits in DCI 770 is sufficient to indicate sub-band indications 782 for each of the plurality of sub-bands (e.g., one or more sub-bands between UEs 710 and BS 750) using a fixed granularity approach. In certain aspects, BS 750 determines a fixed sub-band co-phase indication granularity requirement (e.g., N _sb-co-phase) and a fixed wide-band co-phase indication granularity requirement (e.g., N _wb-co-phase) . It will be appreciated that the fixed wide-band co-phase indication granularity is less precise than the fixed sub-band co-phase indication granularity, and that the configured number of sub-bands (N _sb) can vary.

In certain aspects, BS 750 determines that the number of bits in the available bits is sufficient to indicate separate sub-band co-phase indications (e.g., corresponding to sub-band indications 782) for each of the plurality of sub-bands according to the fixed sub-band co-phase indication granularity requirement using all of the available bits (e.g.,

) . In this case, BS 750 uses the same number of bits (e.g., (N _{Antenna Ports}-1) ×log ₂ N _sb-co-phase) ) for each sub-band co-phase indication for each sub-band in DCI 770. In certain aspects, BS 750 includes the sub-band co-phase indications as sub-band indications 782 according to the fixed sub-band co-phase indication granularity requirement for each of the plurality of sub-bands as uplink precoding information in DCI 770.

In other aspects, BS 750 determines that the number of available bits is not sufficient to indicate separate sub-band co-phase indications for each of the plurality of sub-bands according to the fixed sub-band co-phase indication granularity requirement (e.g.,

) . In this case, BS 750 includes a wide-band co-phase indication as a wide-band indication 780 according to the fixed wide-band co-phase indication granularity requirement as corresponding to the plurality of sub-bands as uplink precoding information in DCI 770 (e.g., when the fixed wide-band co-phase indication granularity requirement is met (e.g., N _co-phase≥log ₂ N _wb-co-phase) . For example, the number of bits used for the wide-band co-phase indication may be log ₂ N _wb-co-phase× (N _{Antenna Ports}-1) .

In certain aspects, when fixed co-phase indication granularity requirements are used as discussed, BS 750 uses one of a bitmap 784 and/or a selection pattern 786 as described below and includes such a bitmap 784 and/or selection pattern 786 in DCI 770.

In certain aspects, when BS 750 determines that the number of available bits is not sufficient to indicate separate sub-band co-phase indications for each of the plurality of sub-bands according to the fixed sub-band co-phase indication granularity requirement and includes wide-band co-phase indication according to the fixed wide-band co-phase granularity requirement, there are remaining bits in the available bits. In certain such aspects, BS 750 may use the remaining bits in DCI 770 to include sub-band differential co-phase indications and a bit-map 784 indicating which sub-bands (e.g., indices of sub-bands) the sub-band differential co-phase indications are for. It will be appreciated that bitmap 784 may be a network implemented bitmap, and may require a bitmap reservation in DCI 770 using some of the available bits. For example, BS 750 uses the remaining bits to indicate sub-band differential co-phase indications for as many sub-bands as possible according to a fixed sub-band differential co-phase indication granularity requirement while also including bitmap 784 (e.g., each sub-band uses

bits) for sub-band differential co-phase indication, on top of the (N _{Antenna Ports}-1) ×log ₂ N _wb-co-phase bits for wide-band co-phase indication) .

In certain such aspects, instead of BS 750 including a bitmap 784 indicating sub-bands corresponding to the sub-band differential co-phase indications, BS 750 includes a sub-band selection pattern 786 (e.g., a formula, number pattern, etc. ) to indicate the sub-bands. It will be appreciated that sub-band selection pattern 786 may be a network implemented selection pattern. In certain aspects, sub-band selection pattern 784 uses N _{sb-sel-pattern} bits in the remaining bits to indicate one of a number of sub-band selection patterns (e.g., number of patterns may be

) .

In other aspects, instead of one or more co-phase indications (e.g., sub-band co-phase indications and/or a wide-band co-phase indication) being included in DCI 770 for the number of groups of antenna ports, one or more of an index of uplink precoding information and number of layers indications (e.g., TPMI indications (e.g., sub-band TPMI indications and/or wide-band TPMI indication) ) are included in DCI 770 for the number of groups of antenna ports. For example, a UE can provide an identification to the network (e.g., including a number of antenna ports (e.g., a number of groups of antenna ports) supported in a reference signal resource (e.g. a sounding reference signal (SRS) resource) as well as a coherent capability associated with one or more of the number of groups of antenna ports, and the maximum number of reference signal resources that can be configured (e.g., configured by a network) ) . In certain aspects, the identification is transmitted by a UE in one or more of an uplink control information (UCI) , medium access control -control element (MAC-CE) , or radio resource control (RRC) to the network. In certain aspects, the network can receive the identification and configures a number of resources (e.g., SRS resources) for the UE, each resource containing the number of antenna ports reported by the UE. In certain aspects, the network transmits the configuration in one or more of a DCI, MAC-CE, or RRC to the UE. The UE receives the network configuration and transmits the resources based on the network configuration. In certain aspects, the network receives the resources and indicates to the UE an index of uplink precoding information and number of layers indications in one or more of a DCI, MAC-CE, or RRC. In certain aspects, the UE receives the index of uplink precoding information and number of layers indicated by the network, and transmits a PUSCH using the precoding information and number of layers indicated by the index.

In certain aspects, the number of bits used for including one or more of an index of uplink precoding information and number of layers indications (e.g., TPMI indications) is referred to as N _tpmi, which corresponds to the number of available bits as discussed. In certain aspects, BS 750 can determine if the number of available bits in DCI 770 is sufficient to indicate separate sub-band index of uplink precoding information and number of layers indications (e.g., corresponding to sub-band indications 782) for each of the plurality of sub-bands (e.g., one or more sub-bands between UEs 710 and BS 750) using a fixed bit-width for the index of uplink precoding information and number of layers indications. In certain aspects, BS 750 determines a fixed sub-band index of uplink precoding information and number of layers indication bit width requirement (e.g., N _sb-tpmi) for all of the groups of antenna ports and a fixed wide-band index of uplink precoding information and number of layers indication bit-width requirement (e.g., N _wb-tpmi) for all of the groups of antenna ports. It will be appreciated that the fixed wide-band index of uplink precoding information and number of layers indication bit width requirement is less than the fixed sub-band index of uplink precoding information and number of layers indication bit width requirement (e.g., N _wb-tpmi＜N _sb-tpmi) . In certain aspects, the configured number of sub-bands (N _sb) varies.

In certain aspects, when BS 750 determines the number of available bits in DCI 770 is sufficient to indicate separate sub-band index of uplink precoding information and number of layers indications for each sub-band according to the fixed sub-band index of uplink precoding information and number of layers indication bit width requirement (e.g., N _tpmi/N _sb≥N _sb-tpmi) , BS 750 includes the sub-band co-phase index of uplink precoding information and number of layers indications as sub-band indications 782 for each sub-band in DCI 770 (e.g., corresponding to N _sb*N _sb-tpmi bits of the available bits) as sub-band indications 782 as corresponding to the plurality of sub-bands as uplink precoding information in DCI 770.

In certain aspects, when BS 750 determines the number available bits in DCI 770 is not sufficient to indicate separate sub-band index of uplink precoding information and number of layers indications for each sub-band according to the fixed sub-band index of uplink precoding information and number of layers indications bit width requirement (e.g., N _tpmi/N _sb＜N _sb-tpmi) , BS 750 includes a wide-band index of uplink precoding information and number of layers indication as a wide-band indication 780 according to the fixed wide-band index of uplink precoding information and number of layers indication bit width requirement as corresponding to the plurality of sub-bands as uplink precoding information in DCI 770 (e.g., using N _wb-tpmi of the available bits, such as when N _wb-tpmi < N _tpmi) .

It will be appreciated that in certain aspects, when BS 750 includes the wide-band index of uplink precoding information and number of layers indication according to the fixed wide-band index of uplink precoding information and number of layers indication bit width requirement in DCI 770, there are remaining bits of the number of available bits. In certain aspects, when there are remaining bits in the number of available bits (e.g., when BS 750 determines the fixed sub-band index of uplink precoding information and number of layers indication width requirement is not met for each sub-band, and the fixed wide-band index of uplink precoding information and number of layers indication bit width requirement is met) BS 750 may include bitmap 784 or selection pattern 786 in DCI 770.

In certain aspects, when BS 750 determines that the number of available bits is not sufficient to indicate separate sub-band index of uplink precoding information and number of layers indications for each of the plurality of sub-bands according to the fixed sub-band index of uplink precoding information and number of layers indication bit width requirement and includes wide-band index of uplink precoding information and number of layers indication according to the fixed wide-band index of uplink precoding information and number of layers indication bit width requirement, there are remaining bits in the available bits. In certain such aspects, BS 750 may use the remaining bits in DCI 770 to include sub-band differential index of uplink precoding information and number of layers indications (corresponding to a type of sub-band differential indication requirement) and a bit-map 784 indicating which sub-bands (e.g., indices of sub-bands) the sub-band differential index of uplink precoding information and number of layers indications are for. It will be appreciated that bitmap 784 may be a network implemented bitmap, and may require a bitmap reservation in DCI 770 using some of the available bits. For example, BS 750 uses the remaining bits to indicate sub-band differential index of uplink precoding information and number of layers indications for as many sub-bands as possible according to a fixed sub-band differential index of uplink precoding information and number of layers indication bit width requirement while also including bitmap 784 (e.g., each sub-band uses N _sb-tpmi-N _wb-tpmibits) for sub-band differential index of uplink precoding information and number of layers indication , on top of the N _wb-tpmi bits for wide-band index of uplink precoding information and number of layers indication) .

In certain such aspects, instead of BS 750 including a bitmap 784 indicating sub-bands corresponding to the sub-band differential index of uplink precoding information and number of layers indications, BS 750 includes a sub-band selection pattern 786 (e.g., a formula, number pattern, etc. ) to indicate the sub-bands. It will be appreciated that sub-band selection pattern 786 may be a network implemented selection pattern. In certain aspects, sub-band selection pattern 784 uses N _{sb-sel-pattern} bits in the remaining bits to indicate one of a number of sub-band selection patterns (e.g., number of patterns may be

) .

In certain aspects, BS 750 transmits DCI 770 to UEs 710 in a downlink transmission 762. UE’s 710 are configured to receive DCI 770 in downlink transmission 762, and send a data stream on an uplink on a number of groups of antenna ports (e.g., 720a and 720b-n) to BS 750. BS 750 receives the data stream from UEs 710, and decodes the data stream based at least in part on DCI 770.

FIG. 8 illustrates a method 800 of adapting a transmission for a plurality of antenna ports in accordance with certain aspects of the disclosure. At step 802, a base station determines a number of available bits in a downlink control information (DCI) for indicating uplink precoding information for each of a number of groups of antenna ports of a user equipment, wherein the uplink precoding information applies to a wide-band comprising a plurality of sub-bands.

At step 804, the base station further indicates the uplink precoding information based on the number of scheduled uplink sub-bands and according to a sub-band indication requirement, using the available bits in DCI for uplink precoding information indication. In certain aspects, the sub-band indication requirement comprises a sub-band co-phase indication and the sub-band indication requirement comprises a sub-band co-phase indication granularity requirement. In other aspects, the sub-band indications each comprise a sub-band index of uplink precoding information and number of layers indication and the sub-band indication requirement comprises a sub-band index of uplink precoding information and number of layers indication bit width requirement.

At step 806, the base station transmits the DCI to the user equipment and the base station receives a data stream from the user equipment on the number of groups of antenna ports.

At step 808, the base station receives a data stream from the user equipment on the number of groups of antenna ports, and decodes the data stream based at least in part on the uplink precoding information.

FIG. 9 illustrates a communications device 900 that may include various components (e.g., corresponding to means-plus-function components) configured to perform operations for the techniques disclosed herein, such as the operations illustrated in FIG. 8. The communications device 900 includes a processing system 902 coupled to a transceiver 908. The transceiver 908 is configured to transmit and receive signals for the communications device 900 via an antenna 910, such as the various signal described herein. The processing system 902 may be configured to perform processing functions for the communications device 900, including processing signals received and/or to be transmitted by the communications device 900.

The processing system 902 includes a processor 904 coupled to a computer-readable medium/memory 912 via a bus 906. In certain aspects, the computer-readable medium/memory 912 is configured to store instructions that when executed by processor 904, cause the processor 904 to perform the operations illustrated in FIG. 8, or other operations for performing the various techniques discussed herein.

In certain aspects, the processing system 902 further includes a determining component 914 for performing the operations illustrated in step 802 of FIG. 8. Additionally, the processing system 902 includes an indicating component 916 for performing the operations illustrated in step 804 of FIG. 8. Additionally, the processing system 902 includes a transmitting and receiving component 918 for performing the operations illustrated in step 806 of FIG. 8. Additionally, the processing system 902 includes a decoding component 1020 for performing the operations illustrated in step 808 of FIG. 8.

The determining component 914, indicating component 916, transmitting and receiving component 918, and decoding component 920 may be coupled to the processor 904 via bus 906. In certain aspects, the determining component 914, integrating component 916, transmitting and receiving component 918, and decoding component 920 may be hardware circuits. In certain aspects, the determining component 914, integrating component 916, transmitting and receiving component 918, and decoding component 920 may be software components that are executed and run on processor 904.

The methods disclosed herein comprise one or more steps or actions for achieving the methods. The method steps and/or actions may be interchanged with one another without departing from the scope of the claims. In other words, unless a specific order of steps or actions is specified, the order and/or use of specific steps and/or actions may be modified without departing from the scope of the claims.

As used herein, a phrase referring to “at least one of” a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover a, b, c, a-b, a-c, b-c, and a-b-c, as well as any combination with multiples of the same element (e.g., a-a, a-a-a, a-a-b, a-a-c, a-b-b, a-c-c, b-b, b-b-b, b-b-c, c-c, and c-c-c or any other ordering of a, b, and c) .

As used herein, the term “determining” encompasses a wide variety of actions. For example, “determining” may include calculating, computing, processing, deriving, investigating, looking up (e.g., looking up in a table, a database or another data structure) , ascertaining and the like. Also, “determining” may include receiving (e.g., receiving information) , accessing (e.g., accessing data in a memory) and the like. Also, “determining” may include resolving, selecting, choosing, establishing and the like.

The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but is to be accorded the full scope consistent with the language of the claims, wherein reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more. ” Unless specifically stated otherwise, the term “some” refers to one or more. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 U.S.C. §112 (f) unless the element is expressly recited using the phrase “means for” or, in the case of a method claim, the element is recited using the phrase “step for. ”

The various operations of methods described above may be performed by any suitable means capable of performing the corresponding functions. The means may include various hardware and/or software component (s) and/or module (s) , including, but not limited to a circuit, an application specific integrated circuit (ASIC) , or processor. Generally, where there are operations illustrated in figures, those operations may have corresponding counterpart means-plus-function components with similar numbering.

The various illustrative logical blocks, modules and circuits described in connection with the present disclosure may be implemented or performed with 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 (PLD) , 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 commercially available 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, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

If implemented in hardware, an example hardware configuration may comprise a processing system in a wireless node. The processing system may be implemented with a bus architecture. The bus may include any number of interconnecting buses and bridges depending on the specific application of the processing system and the overall design constraints. The bus may link together various circuits including a processor, machine-readable media, and a bus interface. The bus interface may be used to connect a network adapter, among other things, to the processing system via the bus. The network adapter may be used to implement the signal processing functions of the PHY layer. In the case of a user terminal 120 (see FIG. 1) , a user interface (e.g., keypad, display, mouse, joystick, etc. ) may also be connected to the bus. The bus may also link various other circuits such as timing sources, peripherals, voltage regulators, power management circuits, and the like, which are well known in the art, and therefore, will not be described any further. The processor may be implemented with one or more general-purpose and/or special-purpose processors. Examples include microprocessors, microcontrollers, DSP processors, and other circuitry that can execute software. Those skilled in the art will recognize how best to implement the described functionality for the processing system depending on the particular application and the overall design constraints imposed on the overall system.

If implemented in software, the functions may be stored or transmitted over as one or more instructions or code on a computer readable medium. Software shall be construed broadly to mean instructions, data, or any combination thereof, whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. Computer-readable media include both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. The processor may be responsible for managing the bus and general processing, including the execution of software modules stored on the machine-readable storage media. A computer-readable storage medium may be coupled to a processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. By way of example, the machine-readable media may include a transmission line, a carrier wave modulated by data, and/or a computer readable storage medium with instructions stored thereon separate from the wireless node, all of which may be accessed by the processor through the bus interface. Alternatively, or in addition, the machine-readable media, or any portion thereof, may be integrated into the processor, such as the case may be with cache and/or general register files. Examples of machine-readable storage media may include, by way of example, RAM (Random Access Memory) , flash memory, ROM (Read Only Memory) , PROM (Programmable Read-Only Memory) , EPROM (Erasable Programmable Read-Only Memory) , EEPROM (Electrically Erasable Programmable Read-Only Memory) , registers, magnetic disks, optical disks, hard drives, or any other suitable storage medium, or any combination thereof. The machine-readable media may be embodied in a computer-program product.

A software module may comprise a single instruction, or many instructions, and may be distributed over several different code segments, among different programs, and across multiple storage media. The computer-readable media may comprise a number of software modules. The software modules include instructions that, when executed by an apparatus such as a processor, cause the processing system to perform various functions. The software modules may include a transmission module and a receiving module. Each software module may reside in a single storage device or be distributed across multiple storage devices. By way of example, a software module may be loaded into RAM from a hard drive when a triggering event occurs. During execution of the software module, the processor may load some of the instructions into cache to increase access speed. One or more cache lines may then be loaded into a general register file for execution by the processor. When referring to the functionality of a software module below, it will be understood that such functionality is implemented by the processor when executing instructions from that software module.

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 (IR) , 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 compact disc (CD) , laser disc, optical disc, digital versatile disc (DVD) , floppy disk, and

disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Thus, in some aspects computer-readable media may comprise non-transitory computer-readable media (e.g., tangible media) . In addition, for other aspects computer-readable media may comprise transitory computer-readable media (e.g., a signal) . Combinations of the above should also be included within the scope of computer-readable media.

Thus, certain aspects may comprise a computer program product for performing the operations presented herein. For example, such a computer program product may comprise a computer-readable medium having instructions stored (and/or encoded) thereon, the instructions being executable by one or more processors to perform the operations described herein. For example, instructions for performing the operations described herein and illustrated in FIG. 8.

Further, it should be appreciated that modules and/or other appropriate means for performing the methods and techniques described herein can be downloaded and/or otherwise obtained by a user terminal and/or base station as applicable. For example, such a device can be coupled to a server to facilitate the transfer of means for performing the methods described herein. Alternatively, various methods described herein can be provided via storage means (e.g., RAM, ROM, a physical storage medium such as a compact disc (CD) or floppy disk, etc. ) , such that a user terminal and/or base station can obtain the various methods upon coupling or providing the storage means to the device. Moreover, any other suitable technique for providing the methods and techniques described herein to a device can be utilized.

It is to be understood that the claims are not limited to the precise configuration and components illustrated above. Various modifications, changes and variations may be made in the arrangement, operation and details of the methods and apparatus described above without departing from the scope of the claims.

Claims

A method of adapting a transmission for a plurality of antenna ports, the method comprising:

determining by a base station a number of available bits in a downlink control information (DCI) for indicating uplink precoding information for each of a number of groups of antenna ports of a user equipment, wherein the uplink precoding information applies to a wide-band comprising a plurality of sub-bands;

indicating the uplink precoding information based on the number of scheduled uplink sub-bands and according to a sub-band indication requirement, using the available bits in DCI for uplink precoding information indication;

transmitting the DCI to the user equipment;

receiving by the base station, a data stream from the user equipment on the number of groups of antenna ports; and

decoding, by the base station the data stream based at least in part on the uplink precoding information.
The method of claim 1, further comprising:

determining if the number of available bits is sufficient to indicate sub-band indications for each of the plurality of sub-bands according to a sub-band indication requirement;

when the number of available bits is determined sufficient, including the sub-band indications according to the sub-band indication requirement for each of the plurality of sub-bands as part of the uplink precoding information in the DCI;

when the number of available bits is determined not sufficient, including a wide-band indication for the wide-band according to a wide-band indication requirement as part of the uplink precoding information in the DCI.
The method of claim 2, wherein the sub-band indications each comprise a sub-band co-phase indication, wherein the wide-band indication comprises a wide-band co-phase indication, wherein the sub-band indication requirement comprises a sub-band co-phase indication granularity requirement, and wherein the wide-band indication requirement comprises a wide-band co-phase indication granularity requirement.
The method of claim 3, wherein the sub-band co-phase indication granularity requirement comprises a minimum granularity requirement for the sub-band co-phase indication.
The method of claim 4, wherein including the sub-band indications according to the sub-band indication requirement for each of the plurality of sub-bands comprises allocating an equal number of bits of the number of available bits to each of the sub-band co-phase indications, the equal number of bits being a floor of the available number of bits divided by a number of the plurality of sub-bands.
The method of claim 4, further comprising, when the number of available bits is determined not sufficient:

determining a number of remaining bits of the number of available bits comprising the number of available bits minus a minimum number of bits required for the wide-band co-phase indication according to the wide-band co-phase indication granularity requirement comprising a minimum granularity requirement for the wide-band co-phase indication;

determining if the number of remaining bits is sufficient to indicate sub-band co-phase indications for each of the plurality of sub-bands according to a sub-band differential co-phase indication granularity requirement, a combination of the sub-band differential co-phase indication granularity requirement and the wide-band co-phase indication granularity requirement being sufficient to meet the minimum granularity requirement for the sub-band co-phase indication; and

when the number of remaining bits is determined sufficient, including sub-band differential co-phase indications according to the sub-band differential co-phase indication granularity requirement for each of the plurality of sub-bands as part of the uplink precoding information in the DCI.
The method of claim 6, further comprising, when the number of remaining bits is determined not sufficient:

determining if the sub-band differential co-phase indication granularity requirement can be decreased;

when it is determined the sub-band differential co-phase indication granularity requirement can be decreased:

decreasing the sub-band differential co-phase indication granularity requirement; and

including the sub-band differential co-phase indications according to the decreased sub-band differential co-phase indication granularity

requirement for each of the plurality of sub-bands as part of the uplink precoding information in the DCI.
The method of claim 7, when it is determined the sub-band differential co-phase indication granularity requirement cannot be decreased, utilizing the remaining bits for indicating the wide-band indication.
The method of claim 3, wherein the sub-band co-phase indication granularity requirement comprises a fixed granularity requirement for the sub-band co-phase indication.
The method of claim 9, wherein including the sub-band indications according to the sub-band indication requirement for each of the plurality of sub-bands comprises allocating an equal number of bits of the number of available bits to each of the sub-band co-phase indications, the equal number of bits being based on the fixed granularity requirement for the sub-band co-phase indication.
The method of claim 9, further comprising, when the number of available bits is determined not sufficient:

determining a number of remaining bits of the number of available bits comprising the number of available bits minus a number of bits required for the wide-band co-phase indication according to a fixed granularity requirement for the wide-band co-phase indication;

determining if the number of remaining bits is sufficient to indicate a bitmap indicating indices of each of the plurality of sub-bands; and

when the number of remaining bits is sufficient, including the bitmap and one or more sub-band differential co-phase indications according to a sub-band differential co-phase indication granularity requirement for one or more of the plurality of sub-bands as part of the uplink precoding information in the DCI, wherein the bitmap indicates the one or more of the plurality of sub-bands, where a number of the one or more sub-band differential co-phase indications is based on the number of remaining bits and the sub-band differential co-phase indication granularity requirement, a combination of the sub-band differential co-phase indication granularity requirement and the wide-band co-phase indication granularity requirement being sufficient to meet the fixed granularity requirement for the sub-band co-phase indication.
The method of claim 9, further comprising, when the number of available bits is determined not sufficient:

determining a number of remaining bits of the number of available bits comprising the number of available bits minus a number of bits required for the wide-band co-phase indication according to a fixed granularity requirement for the wide-band co-phase indication;

determining if the number of remaining bits is sufficient to form a sub-band selection pattern; and

when the number of remaining bits is sufficient, including the sub-band selection pattern and one or more sub-band differential co-phase indications according to a sub-band differential co-phase indication granularity for one or more of the plurality of sub-bands as part of the uplink precoding information in the DCI, wherein the sub-band selection pattern indicates the one or more of the plurality of sub-bands, where a number of the one or more sub-band differential co-phase indications is based on the number of remaining bits and the sub-band differential co-phase indication granularity requirement, a combination of the sub-band differential co-phase indication granularity requirement and the wide-band co-phase indication granularity requirement being sufficient to meet the fixed granularity requirement for the sub-band co-phase indication.
The method of claim 12, further comprising determining the sub-band selection pattern to maximize a number of the one or more sub-band differential co-phase indications while meeting the sub-band differential co-phase indication granularity requirement.
The method of claim 2, wherein the sub-band indications each comprise a sub-band index of uplink precoding information and number of layers, wherein the wide-band indication comprises a wide-band index of uplink precoding information and number of layers indication, wherein the sub-band indication requirement comprises a sub-band index of uplink precoding information and number of layers indication bit width requirement, and wherein the wide-band indication requirement comprises a wide-band index of uplink precoding information and number of layers indication bit width requirement.
The method of claim 14, wherein including the sub-band indications according to the sub-band indication requirement for each of the plurality of sub-bands comprises allocating an equal number of bits of the number of available bits to each of the sub-band index of uplink precoding information and number of layers indications, the equal number of bits being based on the sub-band index of uplink precoding information and number of layers indication bit width requirement.
The method of claim 14, further comprising, when the number of available bits is determined not sufficient:

determining a number of remaining bits of the number of available bits comprising the number of available bits minus a number of bits required for the wide-band index of uplink precoding information and number of layers indication according to the wide-band index of uplink precoding information and number of layers indication bit width requirement;

determining if the number of remaining bits is sufficient to indicate a bitmap indicating indices of each of the plurality of sub-bands; and

when the number of remaining bits is sufficient, including the bitmap and one or more sub-band index of uplink precoding information and number of layers differential indications according to a sub-band index of uplink precoding information and number of layers differential indication bit width requirement for one or more of the plurality of sub-bands as part of the uplink precoding information in the DCI, wherein the bitmap indicates the one or more of the plurality of sub-bands, where a number of the one or more sub-band index of uplink precoding information and number of layers differential indications is based on the number of remaining bits and the sub-band index of uplink precoding information and number of layers differential indication bit width requirement, a combination of the sub-band index of uplink precoding information and number of layers differential indication bit width requirement and the wide-band index of uplink precoding information and number of layers indication bit width requirement being sufficient to meet the sub-band index of uplink precoding information and number of layers indication bit width requirement.
The method of claim 14, further comprising, when the number of available bits is determined not sufficient:

determining a number of remaining bits of the number of available bits comprising the number of available bits minus a number of bits required for the wide-band index of uplink precoding information and number of layers indication according to the wide-band index of uplink precoding information and number of layers indication bit width requirement;

determining if the number of remaining bits is sufficient to form a sub-band selection pattern; and

when the number of remaining bits is sufficient, including the sub-band selection pattern and one or more sub-band index of uplink precoding information and number of layers differential indications according to a sub-band index of uplink precoding information and number of layers differential indication bit width for one or more of the plurality of sub-bands as part of the uplink precoding information in the DCI, wherein the sub-band selection pattern indicates the one or more of the plurality of sub-bands, where a number of the one or more sub-band index of uplink precoding information and number of layers differential indications is based on the number of remaining bits and the sub-band index of uplink precoding information and number of layers differential indication bit width requirement, a combination of the sub-band index of uplink precoding information and number of layers differential indication bit width requirement and the wide-band index of uplink precoding information and number of layers indication bit width requirement being sufficient to meet the sub-band index of uplink precoding information and number of layers indication bit width requirement.
The method of claim 15, further comprising determining the sub-band selection pattern to maximize a number of the one or more sub-band index of uplink precoding information and number of layers differential indications while meeting the sub-band index of uplink precoding information and number of layers differential indication bit width requirement.