WO2021253218A1

WO2021253218A1 - Doppler shift reporting for multiple transmission reception points

Info

Publication number: WO2021253218A1
Application number: PCT/CN2020/096322
Authority: WO
Inventors: Muhammad Sayed Khairy Abdelghaffar; Alexandros MANOLAKOS; Yu Zhang
Original assignee: Qualcomm Incorporated
Priority date: 2020-06-16
Filing date: 2020-06-16
Publication date: 2021-12-23
Also published as: WO2021253664A1

Abstract

Methods, systems, and devices for wireless communications are described. A user equipment (UE) may receive a first reference signal from a first transmission reception point (TRP) and a second reference signal from a second TRP. The UE may estimate a first Doppler shift associated with the first TRP based on receiving the first reference signal and may estimate a second Doppler shift associated with the second TRP based on receiving the second reference signal. The UE may transmit a first indication of the first Doppler shift and a second indication of the second Doppler shift to the first TRP, the second TRP, or both. In some cases, the UE may receive a first Doppler pre-compensated downlink transmission from the first TRP and a second Doppler pre-compensated downlink transmission from the second TRP based on transmitting the indications of the Doppler shifts.

Description

DOPPLER SHIFT REPORTING FOR MULTIPLE TRANSMISSION RECEPTION POINTS

FIELD OF TECHNOLOGY

The following relates generally to wireless communications and more specifically to Doppler shift reporting for multiple transmission reception points (TRPs) .

BACKGROUND

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

In some wireless communications systems, a UE may be in communication with more than one transmission reception point (TRP) (e.g., in a multi-TRP configuration) . Additionally, a UE may experience Doppler shifts when communicating in a multi-TRP configuration. Improved techniques for communicating in a multi-TRP configuration may be desirable.

SUMMARY

The described techniques relate to improved methods, systems, devices, and apparatuses that support Doppler shift reporting for multiple transmission reception points (TRPs) . Generally, the described techniques provide for compensating for a Doppler shift associated with communications between multiple TRPs and a user equipment (UE) . A UE may receive reference signals (e.g., tracking reference signals (TRSs) , synchronization signal block (SSB) transmissions, channel state information-reference signals (CSI-RSs) ) from each TRP of a set of TRPs that is in communication with the UE. The UE may then estimate one or more Doppler metrics (e.g., a Doppler shift, a maximum Doppler spread) associated with each TRP based on receiving the set of reference signals from each TRP. For example, the UE may estimate a first Doppler shift associated with a first TRP based on receiving a first reference signal from the first TRP. Additionally, the UE may estimate a second Doppler shift associated with a second TRP based on receiving a second reference signal from the second TRP. After estimating the one or more Doppler metrics associated with each TRP, the UE may transmit an indication to at least one of the TRPs indicating one or more of the estimated Doppler metrics. After the UE transmits the indications of the estimated Doppler metrics, one or more of the TRPs (e.g., of the set of TRPs) may transmit Doppler pre-compensated downlink transmissions to the UE. For example, a TRP may transmit a physical downlink shared channel (PDSCH) transmission to the UE that has been adjusted by the TRP to account for the Doppler shift (e.g., that is associated with that TRP) estimated by the UE.

A method of wireless communication at a UE is described. The method may include receiving a first reference signal from a first TRP and a second reference signal from a second TRP, estimating a first Doppler shift associated with the first TRP based on receiving the first reference signal, estimating a second Doppler shift associated with the second TRP based on receiving the second reference signal, and transmitting both of a first indication of the first Doppler shift and a second indication of the second Doppler shift, with at least one of the first indication or the second indication being transmitted to at least one of the first TRP or the second TRP .

An apparatus for wireless communication at a UE is described. The apparatus may include a processor, memory coupled with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to receive a first reference signal from a first TRP and a second reference signal from a second TRP, estimate a first Doppler shift associated with the first TRP based on receiving the first reference signal, estimate a second Doppler shift associated with the second TRP based on receiving the second reference signal, and transmit both of a first indication of the first Doppler shift and a second indication of the second Doppler shift, with at least one of the first indication or the second indication being transmitted to at least one of the first TRP or the second TRP .

Another apparatus for wireless communication at a UE is described. The apparatus may include means for receiving a first reference signal from a first TRP and a second reference signal from a second TRP, estimating a first Doppler shift associated with the first TRP based on receiving the first reference signal, estimating a second Doppler shift associated with the second TRP based on receiving the second reference signal, and transmitting both of a first indication of the first Doppler shift and a second indication of the second Doppler shift, with at least one of the first indication or the second indication being transmitted to at least one of the first TRP or the second TRP .

A non-transitory computer-readable medium storing code for wireless communication at a UE is described. The code may include instructions executable by a processor to receive a first reference signal from a first TRP and a second reference signal from a second TRP, estimate a first Doppler shift associated with the first TRP based on receiving the first reference signal, estimate a second Doppler shift associated with the second TRP based on receiving the second reference signal, and transmit both of a first indication of the first Doppler shift and a second indication of the second Doppler shift, with at least one of the first indication or the second indication being transmitted to at least one of the first TRP or the second TRP .

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving, based on transmitting the first indication of the first Doppler shift, a first Doppler pre-compensated downlink transmission from the first TRP via a physical downlink shared channel (PDSCH) , and receiving, based on transmitting the second indication of the second Doppler shift, a second Doppler pre-compensated downlink transmission from the second TRP via the PDSCH.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting an indication of a capability of the UE to estimate the first Doppler shift associated with the first TRP and the second Doppler shift associated with the second TRP, where receiving the first reference signal and the second reference signal may be based on transmitting the indication.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving, from the first TRP or the second TRP, downlink control information (DCI) that may be indicative of a set of resources for transmitting the first indication and the second indication, where transmitting the first indication and the second indication may be based on receiving the DCI.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the DCI triggers the UE to transmit a channel state information (CSI) report for the first reference signal and the second reference signal, the first reference signal may be associated with a first transmission configuration indicator (TCI) state corresponding to the first TRP, and the second reference signal may be associated with a second TCI state corresponding to the second TRP.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the DCI triggers the UE to transmit a CSI report for a single reference signal associated with a first TCI state and a second TCI state, the single reference signal associated with the first TCI state corresponds to the first reference signal, and the single reference signal associated with the second TCI state corresponds to the second reference signal.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for identifying, from the first reference signal and the second reference signal, a reference signal having a higher signal strength, and transmitting an indication of a TRP, from the first TRP or the second TRP, associated with the reference signal having the higher signal strength.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving an indication of a quantity of Doppler shift indications to transmit to the first TRP or the second TRP, where transmitting the first indication of the first Doppler shift and the second indication of the second Doppler shift may be based on receiving the indication of the quantity of Doppler shift indications to transmit.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving, from a set of TRPs including at least the first TRP and the second TRP, a set of reference signals including at least the first reference signal and the second reference signal, identifying the quantity of reference signals of the set of reference signals having a higher signal strength than remaining reference signals of the set of reference signals, and transmitting the quantity of Doppler shift indications each associated with one of the quantity of reference signals based on the identifying.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, transmitting the first indication of the first Doppler shift and the second indication of the second Doppler shift may include operations, features, means, or instructions for transmitting the first indication of the first Doppler shift and the second indication of the second Doppler shift to one of the first TRP or the second TRP.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, transmitting the first indication of the first Doppler shift and the second indication of the second Doppler shift may include operations, features, means, or instructions for transmitting the first indication of the first Doppler shift to the first TRP, and transmitting the second indication of the second Doppler shift to the second TRP.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, transmitting the first indication and the second indication further may include operations, features, means, or instructions for transmitting a CSI report including the first indication of the first Doppler shift, the second indication of the second Doppler shift, or both.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, transmitting the first indication and the second indication further may include operations, features, means, or instructions for transmitting the first indication of the first Doppler shift and the second indication of the second Doppler shift by a physical uplink control channel (PUCCH) or a physical uplink shared channel (PUSCH) .

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving, based on transmitting the first indication of the first Doppler shift and the second indication of the second Doppler shift, a first Doppler pre-compensated downlink transmission from the first TRP and a second Doppler pre-compensated downlink transmission from the second TRP, selecting a channel estimation procedure associated with a Doppler shift less than a threshold Doppler shift based on transmitting the first indication of the first Doppler shift and the second indication of the second Doppler shift, and performing the selected channel estimation procedure on a PDSCH based on receiving the first Doppler pre-compensated downlink transmission and the second Doppler pre-compensated downlink transmission.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving, based on transmitting the first indication of the first Doppler shift and the second indication of the second Doppler shift, a first Doppler pre-compensated downlink transmission from the first TRP and a second Doppler pre-compensated downlink transmission from the second TRP, and identifying a single frequency network downlink transmission based on receiving the first Doppler pre-compensated downlink transmission and the second Doppler pre-compensated downlink transmission.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, receiving the first reference signal from the first TRP and the second reference signal from the second TRP may include operations, features, means, or instructions for receiving the first reference signal from a first remote radio head (RRH) of the first TRP, and receiving the second reference signal from a second RRH of the second TRP, where the first TRP and the second TRP may be the same.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first reference signal and the second reference signal may be TRSs, CSI-RSs, SSB transmissions, or a combination thereof.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first reference signal and the second reference signal may be CSI-RSs, and a set of resources associated with the first reference signal and the second reference signal may be configured for a channel measurement procedure.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving the first reference signal from the first TRP may be based on a first TCI state, and receiving the second reference signal from the second TRP may be based on a second TCI state different than the first TCI state.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first Doppler shift may be associated with a first control resource set (CORESET) index, and the second Doppler shift may be associated with a second CORESET index.

A method of wireless communication at a cell associated with a first TRP and a second TRP is described. The method may include transmitting, by the first TRP, a first reference signal to a UE, transmitting, by the second TRP, a second reference signal to the UE, receiving, from the UE, a first indication of a first Doppler shift associated with the first TRP based on transmitting the first reference signal, and receiving, from the UE, a second indication of a second Doppler shift associated with the second TRP based on transmitting the second reference signal.

An apparatus for wireless communication at a cell associated with a first TRP and a second TRP is described. The apparatus may include a processor, memory coupled with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to transmit, by the first TRP, a first reference signal to a UE, transmit, by the second TRP, a second reference signal to the UE, receive, from the UE, a first indication of a first Doppler shift associated with the first TRP based on transmitting the first reference signal, and receive, from the UE, a second indication of a second Doppler shift associated with the second TRP based on transmitting the second reference signal.

Another apparatus for wireless communication at a cell associated with a first TRP and a second TRP is described. The apparatus may include means for transmitting, by the first TRP, a first reference signal to a UE, transmitting, by the second TRP, a second reference signal to the UE, receiving, from the UE, a first indication of a first Doppler shift associated with the first TRP based on transmitting the first reference signal, and receiving, from the UE, a second indication of a second Doppler shift associated with the second TRP based on transmitting the second reference signal.

A non-transitory computer-readable medium storing code for wireless communication at a cell associated with a first TRP and a second TRP is described. The code may include instructions executable by a processor to transmit, by the first TRP, a first reference signal to a UE, transmit, by the second TRP, a second reference signal to the UE, receive, from the UE, a first indication of a first Doppler shift associated with the first TRP based on transmitting the first reference signal, and receive, from the UE, a second indication of a second Doppler shift associated with the second TRP based on transmitting the second reference signal.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting, based on receiving the first indication of the first Doppler shift, a first Doppler pre-compensated downlink transmission from the first TRP to the UE via a PDSCH, and transmitting, based on receiving the second indication of the second Doppler shift, a second Doppler pre-compensated downlink transmission from the second TRP to the UE via the PDSCH.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving an indication of a capability of the UE to estimate the first Doppler shift associated with the first TRP and the second Doppler shift associated with the second TRP, where transmitting the first reference signal and the second reference signal may be based on receiving the indication.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting, by the first TRP or the second TRP, DCI that may be indicative of a set of resources for transmitting the first indication and the second indication, where receiving the first indication and the second indication may be based on transmitting the DCI.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the DCI triggers the UE to transmit a CSI report for the first reference signal and the second reference signal, the first reference signal may be associated with a first TCI state corresponding to the first TRP, and the second reference signal may be associated with a second TCI state corresponding to the second TRP.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving, from the UE based on transmitting the first reference signal and the second reference signal, an indication of a TRP, from the first TRP or the second TRP, associated with a reference signal having a higher signal strength.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting, to the UE, an indication of a quantity of Doppler shift indications for the UE transmit to the first TRP or the second TRP, where receiving the first indication of the first Doppler shift and the second indication of the second Doppler shift may be based on transmitting the indication of the quantity of Doppler shift indications to the UE.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting, by a set of TRPs including at least the first TRP and the second TRP, a set of reference signals to the UE, the set of reference signals including at least the first reference signal and the second reference signal, and receiving the quantity of Doppler shift indications each associated with one of the quantity of reference signals of the set of reference signals having a higher signal strength than remaining reference signals of the set of reference signals.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, receiving the first indication of the first Doppler shift and the second indication of the second Doppler shift may include operations, features, means, or instructions for receiving, by one of the first TRP or the second TRP, the first indication of the first Doppler shift and the second indication of the second Doppler shift.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, receiving the first indication of the first Doppler shift and the second indication of the second Doppler shift may include operations, features, means, or instructions for receiving, by the first TRP, the first indication of the first Doppler shift, and receiving, by the second TRP, the second indication of the second Doppler shift.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, receiving the first indication of the first Doppler shift and the second indication of the second Doppler shift may include operations, features, means, or instructions for receiving a CSI report including the first indication of the first Doppler shift, the second indication of the second Doppler shift, or both.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, receiving the first indication of the first Doppler shift and the second indication of the second Doppler shift may include operations, features, means, or instructions for receiving the first indication of the first Doppler shift and the second indication of the second Doppler shift by a PUCCH or a PUSCH.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, transmitting the first reference signal and the second reference signal may include operations, features, means, or instructions for transmitting the first reference signal to the UE by a first RRH of the first TRP, and transmitting the second reference signal the UE by a second RRH of the second TRP, where the first TRP and the second TRP may be the same.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting the first reference signal from the first TRP may be based on a first TCI state, and transmitting the second reference signal from the second TRP may be based on a second TCI state different than the first TCI state.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first Doppler shift may be associated with a first CORESET index, and the second Doppler shift may be associated with a second CORESET index.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a system for wireless communications that supports Doppler shift reporting for multiple transmission reception points (TRPs) in accordance with aspects of the present disclosure.

FIG. 2 illustrates an example of a system for wireless communications that supports Doppler shift reporting for multiple TRPs in accordance with aspects of the present disclosure.

FIG. 3 illustrates an example of a process flow that supports Doppler shift reporting for multiple TRPs in accordance with aspects of the present disclosure.

FIGs. 4 and 5 show block diagrams of devices that support Doppler shift reporting for multiple TRPs in accordance with aspects of the present disclosure.

FIG. 6 shows a block diagram of a communications manager that supports Doppler shift reporting for multiple TRPs in accordance with aspects of the present disclosure.

FIG. 7 shows a diagram of a system including a device that supports Doppler shift reporting for multiple TRPs in accordance with aspects of the present disclosure.

FIGs. 8 and 9 show block diagrams of devices that support Doppler shift reporting for multiple TRPs in accordance with aspects of the present disclosure.

FIG. 10 shows a block diagram of a communications manager that supports Doppler shift reporting for multiple TRPs in accordance with aspects of the present disclosure.

FIG. 11 shows a diagram of a system including a device that supports Doppler shift reporting for multiple TRPs in accordance with aspects of the present disclosure.

FIGs. 12 through 15 show flowcharts illustrating methods that support Doppler shift reporting for multiple TRPs in accordance with aspects of the present disclosure.

DETAILED DESCRIPTION

In some wireless communications systems, a user equipment (UE) may support communications with multiple transmission reception points (TRPs) (e.g., in a multi-TRP configuration) . For example, the wireless communications system may include a cell associated with multiple TRPs. Here, a UE may communicate with the cell by more than one TRP. Additionally or alternatively, the wireless communications system may include a cell associated with multiple remote radio heads (RRHs) . Here, the UE may communicate with a TRP by more than one RRH. For example, the UE may receive single frequency network (SFN) transmissions from the multiple TRPs (or, in other cases, multiple RRHs) . That is, the UE may receive multiple identical transmissions from each of the multiple TRPs and utilize them to decode a single downlink transmission. Additionally, the UE may be moving with respect to each of the TRPs. Thus, communications between the UE and each of the TRPs may by associated with Doppler shifts or Doppler spreads. In some cases, the Doppler effects on communications between a UE and the multiple TRPs may not be consistent from one TRP to another TRP. That is, communications between the UE and a first TRP may experience a larger Doppler shift than communications between the UE and a second TRP. In some cases, the variable Doppler effects on communications between the UE and the multiple TRPs may degrade communications (e.g. decrease a reliability of the communications) between the UE and the multiple TRPs.

In some cases, the UE may indicate, to one or more of the multiple TRPs, an estimated Doppler effect (e.g., an estimated Doppler shift, an estimated maximum Doppler spread) associated with each TRP. For example, a UE may receive a first reference signal (e.g., a tracking reference signal (TRS) , a synchronization signal block (SSB) transmission, a channel state information-reference signal (CSI-RS) ) from a first TRP and a second reference signal from a second TRP. Based on the received reference signals, the UE may estimate aspects of a channel (e.g., a Doppler shift, a Doppler spread) between each of the TRPs and UE.For example, the UE may estimate a first Doppler shift associated with the first TRP based on the first reference signal and may estimate a second Doppler shift associated with the second TRP based on the second reference signal. The UE may then transmit a first indication of the estimated Doppler effect (e.g., by an indication of an estimated Doppler shift or an estimated Doppler spread) to one or more of the multiple TRPs. For example, the UE may transmit a first indication of the first Doppler shift and a second indication of the second Doppler shift (e.g., to the first TRP, to the second TRP, or to the first and the second TRPs) . In some examples, the UE may support communications with multiple RRHs located at different geographic locations of a single TRP. Here, the UE may receive the first reference signal from a first RRH of the first TRP and the second reference signal from a second RRH of the second TRP, where the first TRP and the second TRP are the same TRP.

Based on receiving an indication of the estimated Doppler effect, one or more of the TRPs may pre-compensate downlink transmissions (e.g., prior to transmitting the downlink transmissions to the UE) to account for the estimated Doppler effect associated with that TRP. Thus, the UE may receive downlink communications from the TRPs that have been Doppler pre-compensated. In some cases, this may decrease the Doppler effect on downlink communications received by the UE from multiple TRPs thereby increasing downlink performance.

Aspects of the disclosure are initially described in the context of wireless communications systems. Aspects of the disclosure are then described in the context of process flows. Aspects of the disclosure are further illustrated by and described with reference to apparatus diagrams, system diagrams, and flowcharts that relate to Doppler shift reporting for multiple TRPs.

FIG. 1 illustrates an example of a wireless communications system 100 that supports Doppler shift reporting for multiple TRPs in accordance with aspects of the present disclosure. The wireless communications system 100 may include one or more base stations 105, one or more UEs 115, and a core network 130. In some examples, the wireless communications system 100 may be a Long Term Evolution (LTE) network, an LTE-Advanced (LTE-A) network, an LTE-A Pro network, or a New Radio (NR) network. In some examples, the wireless communications system 100 may support enhanced broadband communications, ultra-reliable (e.g., mission critical) communications, low latency communications, communications with low-cost and low-complexity devices, or any combination thereof.

The base stations 105 may be dispersed throughout a geographic area to form the wireless communications system 100 and may be devices in different forms or having different capabilities. The base stations 105 and the UEs 115 may wirelessly communicate via one or more communication links 125. Each base station 105 may provide a coverage area 110 over which the UEs 115 and the base station 105 may establish one or more communication links 125. The coverage area 110 may be an example of a geographic area over which a base station 105 and a UE 115 may support the communication of signals according to one or more radio access technologies.

The UEs 115 may be dispersed throughout a coverage area 110 of the wireless communications system 100, and each UE 115 may be stationary, or mobile, or both at different times. The UEs 115 may be devices in different forms or having different capabilities. Some example UEs 115 are illustrated in FIG. 1. The UEs 115 described herein may be able to communicate with various types of devices, such as other UEs 115, the base stations 105, or network equipment (e.g., core network nodes, relay devices, integrated access and backhaul (IAB) nodes, or other network equipment) , as shown in FIG. 1.

The base stations 105 may communicate with the core network 130, or with one another, or both. For example, the base stations 105 may interface with the core network 130 through one or more backhaul links 120 (e.g., via an S1, N2, N3, or other interface) . The base stations 105 may communicate with one another over the backhaul links 120 (e.g., via an X2, Xn, or other interface) either directly (e.g., directly between base stations 105) , or indirectly (e.g., via core network 130) , or both. In some examples, the backhaul links 120 may be or include one or more wireless links.

One or more of the base stations 105 described herein may include or may be referred to by a person having ordinary skill in the art as a base transceiver station, a radio base station, an access point, a radio transceiver, a NodeB, an eNodeB (eNB) , a next-generation NodeB or a giga-NodeB (either of which may be referred to as a gNB) , a Home NodeB, a Home eNodeB, or other suitable terminology.

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

The UEs 115 described herein may be able to communicate with various types of devices, such as other UEs 115 that may sometimes act as relays as well as the base stations 105 and the network equipment including macro eNBs or gNBs, small cell eNBs or gNBs, or relay base stations, among other examples, as shown in FIG. 1.

The UEs 115 and the base stations 105 may wirelessly communicate with one another via one or more communication links 125 over one or more carriers. The term “carrier” may refer to a set of radio frequency spectrum resources having a defined physical layer structure for supporting the communication links 125. For example, a carrier used for a communication link 125 may include a portion of a radio frequency spectrum band (e.g., a bandwidth part (BWP) ) that is operated according to one or more physical layer channels for a given radio access technology (e.g., LTE, LTE-A, LTE-A Pro, NR) . Each physical layer channel may carry acquisition signaling (e.g., synchronization signals, system information) , control signaling that coordinates operation for the carrier, user data, or other signaling. The wireless communications system 100 may support communication with a UE 115 using carrier aggregation or multi-carrier operation. A UE 115 may be configured with multiple downlink component carriers and one or more uplink component carriers according to a carrier aggregation configuration. Carrier aggregation may be used with both frequency division duplexing (FDD) and time division duplexing (TDD) component carriers.

In some examples (e.g., in a carrier aggregation configuration) , a carrier may also have acquisition signaling or control signaling that coordinates operations for other carriers. A carrier may be associated with a frequency channel (e.g., an evolved universal mobile telecommunication system terrestrial radio access (E-UTRA) absolute radio frequency channel number (EARFCN) ) and may be positioned according to a channel raster for discovery by the UEs 115. A carrier may be operated in a standalone mode where initial acquisition and connection may be conducted by the UEs 115 via the carrier, or the carrier may be operated in a non-standalone mode where a connection is anchored using a different carrier (e.g., of the same or a different radio access technology) .

The communication links 125 shown in the wireless communications system 100 may include uplink transmissions from a UE 115 to a base station 105, or downlink transmissions from a base station 105 to a UE 115. Carriers may carry downlink or uplink communications (e.g., in an FDD mode) or may be configured to carry downlink and uplink communications (e.g., in a TDD mode) .

Signal waveforms transmitted over a carrier may be made up of multiple subcarriers (e.g., using multi-carrier modulation (MCM) techniques such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform spread OFDM (DFT-S-OFDM) ) . In a system employing MCM techniques, a resource element may consist of one symbol period (e.g., a duration of one modulation symbol) and one subcarrier, where the symbol period and subcarrier spacing are inversely related. The number of bits carried by each resource element may depend on the modulation scheme (e.g., the order of the modulation scheme, the coding rate of the modulation scheme, or both) . Thus, the more resource elements that a UE 115 receives and the higher the order of the modulation scheme, the higher the data rate may be for the UE 115. A wireless communications resource may refer to a combination of a radio frequency spectrum resource, a time resource, and a spatial resource (e.g., spatial layers or beams) , and the use of multiple spatial layers may further increase the data rate or data integrity for communications with a UE 115.

The time intervals for the base stations 105 or the UEs 115 may be expressed in multiples of a basic time unit which may, for example, refer to a sampling period of T _s=1/ (Δf _max·N _f) seconds, where Δf _max may represent the maximum supported subcarrier spacing, and N _f may represent the maximum supported discrete Fourier transform (DFT) size. Time intervals of a communications resource may be organized according to radio frames each having a specified duration (e.g., 10 milliseconds (ms) ) . Each radio frame may be identified by a system frame number (e.g., ranging from 0 to 1023) .

Each frame may include multiple consecutively numbered subframes or slots, and each subframe or slot may have the same duration. In some examples, a frame may be divided (e.g., in the time domain) into subframes, and each subframe may be further divided into a number of slots. Alternatively, each frame may include a variable number of slots, and the number of slots may depend on subcarrier spacing. Each slot may include a number of symbol periods (e.g., depending on the length of the cyclic prefix prepended to each symbol period) . In some wireless communications systems 100, a slot may further be divided into multiple mini-slots containing one or more symbols. Excluding the cyclic prefix, each symbol period may contain one or more (e.g., N _f) sampling periods. The duration of a symbol period may depend on the subcarrier spacing or frequency band of operation.

A subframe, a slot, a mini-slot, or a symbol may be the smallest scheduling unit (e.g., in the time domain) of the wireless communications system 100 and may be referred to as a transmission time interval (TTI) . In some examples, the TTI duration (e.g., the number of symbol periods in a TTI) may be variable. Additionally or alternatively, the smallest scheduling unit of the wireless communications system 100 may be dynamically selected (e.g., in bursts of shortened TTIs (sTTIs) ) .

Physical channels may be multiplexed on a carrier according to various techniques. A physical control channel and a physical data channel may be multiplexed on a downlink carrier, for example, using one or more of time division multiplexing (TDM) techniques, frequency division multiplexing (FDM) techniques, or hybrid TDM-FDM techniques. A control region (e.g., a control resource set (CORESET) ) for a physical control channel may be defined by a number of symbol periods and may extend across the system bandwidth or a subset of the system bandwidth of the carrier. One or more control regions (e.g., CORESETs) may be configured for a set of the UEs 115. For example, one or more of the UEs 115 may monitor or search control regions for control information according to one or more search space sets, and each search space set may include one or multiple control channel candidates in one or more aggregation levels arranged in a cascaded manner. An aggregation level for a control channel candidate may refer to a number of control channel resources (e.g., control channel elements (CCEs) ) associated with encoded information for a control information format having a given payload size. Search space sets may include common search space sets configured for sending control information to multiple UEs 115 and UE-specific search space sets for sending control information to a specific UE 115.

Each base station 105 may provide communication coverage via one or more cells, for example a macro cell, a small cell, a hot spot, or other types of cells, or any combination thereof. The term “cell” may refer to a logical communication entity used for communication with a base station 105 (e.g., over a carrier) and may be associated with an identifier for distinguishing neighboring cells (e.g., a physical cell identifier (PCID) , a virtual cell identifier (VCID) , or others) . In some examples, a cell may also refer to a geographic coverage area 110 or a portion of a geographic coverage area 110 (e.g., a sector) over which the logical communication entity operates. Such cells may range from smaller areas (e.g., a structure, a subset of structure) to larger areas depending on various factors such as the capabilities of the base station 105. For example, a cell may be or include a building, a subset of a building, or exterior spaces between or overlapping with geographic coverage areas 110, among other examples.

A macro cell generally covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by the UEs 115 with service subscriptions with the network provider supporting the macro cell. A small cell may be associated with a lower-powered base station 105, as compared with a macro cell, and a small cell may operate in the same or different (e.g., licensed, unlicensed) frequency bands as macro cells. Small cells may provide unrestricted access to the UEs 115 with service subscriptions with the network provider or may provide restricted access to the UEs 115 having an association with the small cell (e.g., the UEs 115 in a closed subscriber group (CSG) , the UEs 115 associated with users in a home or office) . A base station 105 may support one or multiple cells and may also support communications over the one or more cells using one or multiple component carriers.

In some examples, a carrier may support multiple cells, and different cells may be configured according to different protocol types (e.g., MTC, narrowband IoT (NB-IoT) , enhanced mobile broadband (eMBB) ) that may provide access for different types of devices.

In some examples, a base station 105 may be movable and therefore provide communication coverage for a moving geographic coverage area 110. In some examples, different geographic coverage areas 110 associated with different technologies may overlap, but the different geographic coverage areas 110 may be supported by the same base station 105. In other examples, the overlapping geographic coverage areas 110 associated with different technologies may be supported by different base stations 105. The wireless communications system 100 may include, for example, a heterogeneous network in which different types of the base stations 105 provide coverage for various geographic coverage areas 110 using the same or different radio access technologies.

The wireless communications system 100 may support synchronous or asynchronous operation. For synchronous operation, the base stations 105 may have similar frame timings, and transmissions from different base stations 105 may be approximately aligned in time. For asynchronous operation, the base stations 105 may have different frame timings, and transmissions from different base stations 105 may, in some examples, not be aligned in time. The techniques described herein may be used for either synchronous or asynchronous operations.

The wireless communications system 100 may be configured to support ultra-reliable communications or low-latency communications, or various combinations thereof. For example, the wireless communications system 100 may be configured to support ultra-reliable low-latency communications (URLLC) or mission critical communications. The UEs 115 may be designed to support ultra-reliable, low-latency, or critical functions (e.g., mission critical functions) . Ultra-reliable communications may include private communication or group communication and may be supported by one or more mission critical services such as mission critical push-to-talk (MCPTT) , mission critical video (MCVideo) , or mission critical data (MCData) . Support for mission critical functions may include prioritization of services, and mission critical services may be used for public safety or general commercial applications. The terms ultra-reliable, low-latency, mission critical, and ultra-reliable low-latency may be used interchangeably herein.

In some examples, a UE 115 may also be able to communicate directly with other UEs 115 over a device-to-device (D2D) communication link 135 (e.g., using a peer-to-peer (P2P) or D2D protocol) . One or more UEs 115 utilizing D2D communications may be within the geographic coverage area 110 of a base station 105. Other UEs 115 in such a group may be outside the geographic coverage area 110 of a base station 105 or be otherwise unable to receive transmissions from a base station 105. In some examples, groups of the UEs 115 communicating via D2D communications may utilize a one-to-many (1: M) system in which each UE 115 transmits to every other UE 115 in the group. In some examples, a base station 105 facilitates the scheduling of resources for D2D communications. In other cases, D2D communications are carried out between the UEs 115 without the involvement of a base station 105.

The core network 130 may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. The core network 130 may be an evolved packet core (EPC) or 5G core (5GC) , which may include at least one control plane entity that manages access and mobility (e.g., a mobility management entity (MME) , an access and mobility management function (AMF) ) and at least one user plane entity that routes packets or interconnects to external networks (e.g., a serving gateway (S-GW) , a Packet Data Network (PDN) gateway (P-GW) , or a user plane function (UPF) ) . The control plane entity may manage non-access stratum (NAS) functions such as mobility, authentication, and bearer management for the UEs 115 served by the base stations 105 associated with the core network 130. User IP packets may be transferred through the user plane entity, which may provide IP address allocation as well as other functions. The user plane entity may be connected to the network operators IP services 150. The operators IP services 150 may include access to the Internet, Intranet (s) , an IP Multimedia Subsystem (IMS) , or a Packet-Switched Streaming Service.

Some of the network devices, such as a base station 105, may include subcomponents such as an access network entity 140, which may be an example of an access node controller (ANC) . Each access network entity 140 may communicate with the UEs 115 through one or more other access network transmission entities 145, which may be referred to as radio heads, smart radio heads, or TRPs. Each access network transmission entity 145 may include one or more antenna panels. In some configurations, various functions of each access network entity 140 or base station 105 may be distributed across various network devices (e.g., radio heads and ANCs) or consolidated into a single network device (e.g., a base station 105) .

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

The wireless communications system 100 may also operate in a super high frequency (SHF) region using frequency bands from 3 GHz to 30 GHz, also known as the centimeter band, or in an extremely high frequency (EHF) region of the spectrum (e.g., from 30 GHz to 300 GHz) , also known as the millimeter band. In some examples, the wireless communications system 100 may support millimeter wave (mmW) communications between the UEs 115 and the base stations 105, and EHF antennas of the respective devices may be smaller and more closely spaced than UHF antennas. In some examples, this may facilitate use of antenna arrays within a device. The propagation of EHF transmissions, however, may be subject to even greater atmospheric attenuation and shorter range than SHF or UHF transmissions. The techniques disclosed herein may be employed across transmissions that use one or more different frequency regions, and designated use of bands across these frequency regions may differ by country or regulating body.

The wireless communications system 100 may utilize both licensed and unlicensed radio frequency spectrum bands. For example, the wireless communications system 100 may employ License Assisted Access (LAA) , LTE-Unlicensed (LTE-U) radio access technology, or NR technology in an unlicensed band such as the 5 GHz industrial, scientific, and medical (ISM) band. When operating in unlicensed radio frequency spectrum bands, devices such as the base stations 105 and the UEs 115 may employ carrier sensing for collision detection and avoidance. In some examples, operations in unlicensed bands may be based on a carrier aggregation configuration in conjunction with component carriers operating in a licensed band (e.g., LAA) . Operations in unlicensed spectrum may include downlink transmissions, uplink transmissions, P2P transmissions, or D2D transmissions, among other examples.

A base station 105 or a UE 115 may be equipped with multiple antennas, which may be used to employ techniques such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communications, or beamforming. The antennas of a base station 105 or a UE 115 may be located within one or more antenna arrays or antenna panels, which may support MIMO operations or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays may be co-located at an antenna assembly, such as an antenna tower. In some examples, antennas or antenna arrays associated with a base station 105 may be located in diverse geographic locations. A base station 105 may have an antenna array with a number of rows and columns of antenna ports that the base station 105 may use to support beamforming of communications with a UE 115. Likewise, a UE 115 may have one or more antenna arrays that may support various MIMO or beamforming operations. Additionally or alternatively, an antenna panel may support radio frequency beamforming for a signal transmitted via an antenna port.

The base stations 105 or the UEs 115 may use MIMO communications to exploit multipath signal propagation and increase the spectral efficiency by transmitting or receiving multiple signals via different spatial layers. Such techniques may be referred to as spatial multiplexing. The multiple signals may, for example, be transmitted by the transmitting device via different antennas or different combinations of antennas. Likewise, the multiple signals may be received by the receiving device via different antennas or different combinations of antennas. Each of the multiple signals may be referred to as a separate spatial stream and may carry bits associated with the same data stream (e.g., the same codeword) or different data streams (e.g., different codewords) . Different spatial layers may be associated with different antenna ports used for channel measurement and reporting. MIMO techniques include single-user MIMO (SU-MIMO) , where multiple spatial layers are transmitted to the same receiving device, and multiple-user MIMO (MU-MIMO) , where multiple spatial layers are transmitted to multiple devices.

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

A base station 105 or a UE 115 may use beam sweeping techniques as part of beam forming operations. For example, a base station 105 may use multiple antennas or antenna arrays (e.g., antenna panels) to conduct beamforming operations for directional communications with a UE 115. Some signals (e.g., synchronization signals, reference signals, beam selection signals, or other control signals) may be transmitted by a base station 105 multiple times in different directions. For example, the base station 105 may transmit a signal according to different beamforming weight sets associated with different directions of transmission. Transmissions in different beam directions may be used to identify (e.g., by a transmitting device, such as a base station 105, or by a receiving device, such as a UE 115) a beam direction for later transmission or reception by the base station 105.

Some signals, such as data signals associated with a particular receiving device, may be transmitted by a base station 105 in a single beam direction (e.g., a direction associated with the receiving device, such as a UE 115) . In some examples, the beam direction associated with transmissions along a single beam direction may be determined based on a signal that was transmitted in one or more beam directions. For example, a UE 115 may receive one or more of the signals transmitted by the base station 105 in different directions and may report to the base station 105 an indication of the signal that the UE 115 received with a highest signal quality or an otherwise acceptable signal quality.

In some examples, transmissions by a device (e.g., by a base station 105 or a UE 115) may be performed using multiple beam directions, and the device may use a combination of digital precoding or radio frequency beamforming to generate a combined beam for transmission (e.g., from a base station 105 to a UE 115) . The UE 115 may report feedback that indicates precoding weights for one or more beam directions, and the feedback may correspond to a configured number of beams across a system bandwidth or one or more sub-bands. The base station 105 may transmit a reference signal (e.g., a cell-specific reference signal (CRS) , a CSI-RS, which may be precoded or unprecoded. The UE 115 may provide feedback for beam selection, which may be a precoding matrix indicator (PMI) or codebook-based feedback (e.g., a multi-panel type codebook, a linear combination type codebook, a port selection type codebook) . Although these techniques are described with reference to signals transmitted in one or more directions by a base station 105, a UE 115 may employ similar techniques for transmitting signals multiple times in different directions (e.g., for identifying a beam direction for subsequent transmission or reception by the UE 115) or for transmitting a signal in a single direction (e.g., for transmitting data to a receiving device) .

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

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

Wireless communications systems 100 may support a multi-TRP configuration. For example, a UE 115 may receive downlink transmissions (e.g., via a physical downlink shared channel (PDSCH) ) from multiple TRPs. Thus, the UE 115 may utilize one or more multiplexing schemes (e.g., spatial multiplexing) to receive and decode each of the downlink transmissions from the multiple TRPs. Additionally, the UE 115 may decode each of the downlink transmissions according to a transmission configuration indicator (TCI) state (e.g., a beam configuration) associated with the downlink transmission. In some cases, each TCI state may correspond to a quasi-colocation (QCL) relationship. For example, the UE 115-a may assume that certain channel estimations may be similar for transmissions associated with a same TCI state (e.g., due to the QCL relationship) . In some cases of the multi-TRP configuration, a single TRP may transmit downlink control information (DCI) selecting multiple TCI states each associated with a downlink transmission from one of the multiple TRPs (e.g., when the multiple TRPs have an ideal backhaul communication link) . For example, a first TRP may transmit DCI indicating a first TCI state for a subsequent downlink transmission by the first TRP. In this example, the second TRP may not transmit DCI to the UE 115. That is, although the UE 115 is in communication with multiple TRPs, the UE 115 may only receive DCI from the first TRP. Here, the UE 115 may receive downlink transmissions from multiple TRPs according to a single TCI state (e.g., indicated by the DCI) . Thus, the UE 115 may not identify which TRP transmits different received downlink transmissions.

In some other cases of a multi-TRP configuration, the UE 115 may receive DCI from each of the multiple TRPs. In such cases, the UE 115 may decode downlink transmissions according to a TCI state indicated by the DCI transmitted by the same TRP. For example, the UE 115 may decode a downlink transmission from a first TRP according to a TCI state indicated by the first TRP within DCI. Additionally, the UE 115 may decode a downlink transmission from a second TRP according to a TCI state indicated by the second TRP within DCI. In some cases, a UE 115 may identify which TRP a TCI state is associated with based on a control region (e.g., a CORESET) associated with the DCI indicating the TCI state. That is, the UE 115 may receive the DCI from a TRP by a CORESET in a physical control channel (e.g., a PDCCH) . The CORESET may be associated with a CORESET index (e.g., a CORESETPoolIndex) that indicates one or more TRPs. Thus, based on the CORESET associated with the received DCI, the UE 115 may identify a TRP or group of TRPs that transmitted the DCI. In turn, the UE 115 may identify a TRP or group of TRPs associated with the TCI state indicated by the DCI.

Additionally, a UE 115 in communication with more than one TRP may receive SFN transmissions from each of the TRPs. That is, more than one TRP may transmit a same downlink transmission (e.g., a PDSCH transmission) to the UE 115 over a same set of frequency resources. Thus, the UE 115 may receive a same downlink transmission from more than one TRP. In some cases, this may increase a spatial diversity of the downlink transmission and may improve a reliability of the downlink transmission when compared to a downlink transmission that is transmitted by a single TRP. In some cases, an SFN transmission may be associated with a single TCI state. That is, the UE 115 may receive the downlink transmission based on a single TCI state and each TRP may transmit the downlink transmission according to the single TCI state. In some other cases, an SFN transmission may be associated with more than one TCI state. That is, the UE 115 may receive the downlink transmission based on more than one TCI state. Additionally, each TRP may transmit the downlink transmission based on the more than one TCI state.

To properly interpret received transmissions from one or more TRPs, the UE 115 may determine one or more properties of a channel over which the one or more transmissions were made. For example, the UE 115 may estimate aspects of a radio channel based on one or more reference signals transmitted over the channel between the TRP and the UE 115. The channel estimations may assist the UE 115 in interpreting received downlink transmissions and relevant channel state information (CSI) , among other examples. In some cases, multiple TRPs may transmit reference signals to the UE 115 for channel estimation that are SFN reference signals. Thus, the UE 115 may perform channel estimations based on the SFN channel associated with multiple reference signal transmissions from different TRPs. In some cases, the UE 115 may be moving with respect to one or more of the TRPs, resulting in a Doppler effect impacting one or more of the reference signal transmissions. Additionally, a relative movement between the UE 115 and a first TRP may be different than a relative movement between the UE 115 and a second TRP. Thus, performing a single channel estimation on the SFN channel may not reliably estimate the Doppler effects on the channel.

In some other examples, the UE 115 may instead receive reference signals from the multiple TRPs that are not SFN reference signal transmissions. Thus, the UE 115 may perform a channel estimation (e.g., to estimate one or more Doppler metrics associated with the channel) on each channel associated with a single TRP. In some cases, this may enable the UE 115 to more reliably estimate the Doppler effects on the channels (e.g., when compared to estimating the Doppler effects on an SFN channel) .

For example, the UE 115 may receive a reference signal from each TRP of the multiple TRPs. That is, a UE 115 may support communications with a first TRP and a second TRP. The UE 115 may receive a first reference signal from the first TRP and a second reference signal from the second TRP. In some cases, the first reference signal may be associated with a first Doppler shift and the second reference signal may be associated a second Doppler shift (e.g., different from the first Doppler shift, the same as the first Doppler shift) . For example, the first Doppler shift may cause the UE 115 to detect a first frequency shift of a transmission received from the first TRP, and the second Doppler shift may cause the UE 115 to detect a second frequency shift of a transmission received from the second TRP. The UE 115 may estimate the first Doppler shift based on the first reference signal received from the first TRP and may estimate the second Doppler shift based on the second reference signal received from the second TRP. In some cases, the first TRP and the second TRP may be the same TRP. Here, the UE 115 may receive the first reference signal from a first RRH of the first TRP and the second reference signal from a second RRH of the second TRP, where the first TRP and the second TRP are the same TRP.

The UE 115 may then transmit a first indication of the first Doppler shift and a second indication of the second Doppler shift. In some cases, the UE 115 may transmit the first indication of the first Doppler shift and the second indication of the second Doppler shift to the first TRP. Here, the first TRP may forward the second indication of the second Doppler shift to the second TRP (e.g., via a backhaul link between the first TRP and the second TRP) . In other cases, the UE 115 may transmit the first indication of the first Doppler shift to the first TRP and the second indication of the second Doppler shift to the second TRP. In some examples, the first TRP may Doppler pre-compensate a first downlink transmission based on the first Doppler shift, and the second TRP may Doppler pre-compensate a second downlink transmission (e.g., that is an SFN transmission with the first downlink transmission) based on the second Doppler shift. Thus, the first TRP may transmit the first Doppler pre-compensated downlink transmission to the UE 115 via a PDSCH, and the second TRP may transmit the second Doppler pre-compensated downlink transmission to the UE 115 via the PDSCH.

FIG. 2 illustrates an example of a wireless communications system 200 that supports Doppler shift reporting for multiple TRPs in accordance with aspects of the present disclosure. In some examples, wireless communications system 200 may implement aspects of wireless communications system 100. The wireless communications system 200 may include a UE 115-a, which may be an example of a UE 115 as described with reference to FIG. 1. Additionally, the wireless communications system 200 may include TRPs 205, which may be examples of access network transmission entities 145 as described with reference to FIG. 1. In wireless communications system 200, the UE 115-a may be configured to communicate with multiple TRPs 205 (e.g., TRP 205-a and TRP 205-b) .

The UE 115-a may be in communication with a serving cell by the first TRP 205-a and the second TRP 205-b. In some cases, the UE 115-a may additionally be in communication with additional TRPs 205 associated with the serving cell. The UE 115-a may receive one or more indications (e.g., via RRC signaling, MAC-CE signaling, DCI transmissions) of active TCI states associated with receiving downlink transmissions from the TRP 205-a and the TRP 205-b. For example, the TRP 205-a may transmit DCI to the UE 115-a indicating a first TCI state for communications between the TRP 205-a and the UE 115-a. Additionally, the TRP 205-b may transmit DCI to the UE 115-a indicating a second TCI state (e.g., different from the first TCI state) for communications between the TRP 205-b and the UE 115-a. In another example, one of the TRPs 205 may transmit DCI to the UE 115-a that indicates the first TCI state for communications between the UE 115-a and the TRP 205-a and the second TCI state for communications between the UE 115-a and the TRP 205-b.

The UE 115-a may be capable of estimating Doppler metrics associated with the different channels between the UE 115-a and the TRPs 205 (e.g., the channel between the UE 115-a and the TRP 205-a and the channel between the UE 115-a and the TRP 205-b) . Thus, the UE 115-a may transmit an indication a capability of the UE 115-a to estimate a Doppler metrics. For example, the UE 115-a may transmit the indication of the UE capability to the first TRP 205-a and the second TRP 205-b. In other examples, the UE 115-a may transmit the indication of the UE capability to one of the first TRP 205-a or the second TRP 205-b. In this example, the TRP 205 that receives the indication of the UE capability to estimate the Doppler metrics may communicate the UE capability to the other TRP 205 (e.g., by the backhaul link 240) . Based on determining that the UE 115-a is capable of estimating Doppler metrics for each of the channels between the UE 115-a and multiple TRPs 205, one of the TRPs 205 may transmit an indication (e.g., via) configuring the UE 115-a to perform the Doppler estimation.

The first TRP 205-a may transmit the first reference signal 210-a by the first TCI state and the second TRP 205-a may transmit the second reference signal 210-b by the second TCI state. Thus, the UE 115-a may receive the first reference signal 210-a according to a different TCI state than the second reference signal 210-b. This may enable the UE 115-a to perform a first channel estimation procedure using the first reference signal 210-a separately from performing a second channel estimation procedure using the second reference signal 210-b. When performing the channel estimation procedures, the UE 115-a may use the reference signals 210 to determine channel condition indicators (e.g., channel quality indicator (CQI) , reference signal received power (RSRP) , reference signal received quality (RSRQ) , signal-to-interference-plus-noise ratio (SINR) , rank indicator (RI) ) for downlink transmissions associated with each TRP 205. That is, the UE 115-a may determine a signal strength associated with each of the received reference signals 210 (e.g., based on the RSRQ, the SINR) .

In some cases, the first TRP 205-a and the second TRP 205-b may be the same TRP 205. For example, a TRP 205 (e.g., the first TRP 205-a, the second TRP 205-b) may include multiple RRHs located at different geographic locations of the TRP 205. The TRP 205 may transmit the first reference signal 210-a by a first RRH of the TRP 205 and the second reference signal 210-b by a second RRH of the TRP 205. Thus, the UE 115-a may receive the first reference signal 210-a from the first RRH of the TRP 205 and the second reference signal 210-b from the second RRH of the TRP 205.

Additionally, the UE 115-a may estimate one or more Doppler metrics (e.g., a Doppler shift, a Doppler spread) associated with each TRP 205 based on the received reference signals 210. For example, the UE 115-a may estimate a first Doppler shift or a first Doppler spread associated with the first TRP 205-a based on receiving the first reference signal 210-a. Additionally, the UE 115-a may estimate a second Doppler shift or a second Doppler spread associated with the second TRP 205-b based on receiving the second reference signal 210-b.

The UE 115-a may receive the reference signals 210 based on a TCI state corresponding to a TRP 205. In some cases, one or both of the TRPs 205 may transmit an indication (e.g., via DCI) of a first TCI state associated with the first reference signal 210-a and a second TCI state (e.g., unique from the first TCI state) associated with the second reference signal 210-b. In some cases, the UE 115-a may identify with which TRP 205 is associated with each reference signal 210 based on a TCI state associated with the reference signal 210 (e.g., based on a CORESET associated with the received DCI indicating the TCI states) . That is, the CORESET associated with the DCI indication may be associated with a CORESET index (e.g., a CORESETPoolIndex) that indicates one or more TRPs 205. For example, the first TRP 205-a may be associated with a first CORESET index and the TRP 205-b may associated with a second CORESET index. Here, the UE 115-a may identify that the first TCI state is associated with the first reference signal 210-a based on a CORESET of the indication of the first TCI state being associated with the first CORESET index. Additionally, the UE 115-a may identify that the second TCI state is associated with the second reference signal 210-b based on a CORESET of the indication of the second TCI state being associated with the second CORESET index.

The UE 115-a may decode the reference signals 210 based on a TCI state associated with the reference signal 210. For example, the UE 115-a may decode the first reference signal 210-a according to the first TCI state and may decode the second reference signal 210-b according to the second TCI state. The UE 115-a may then estimate the first Doppler shift based on the first reference signal 210-a and may estimate the second Doppler shift based on the second reference signal 210-b. In some cases, the UE 115-a may associate the first Doppler shift with the first CORESET index and the second Doppler shift with the second CORESET index.

The UE 115-a may indicate the estimated Doppler metrics (e.g., an estimated Doppler shift, an estimated Doppler spread, or both) associated with the first TRP 205-a and the second TRP 205-b to one or both of the TRPs 205.

In some cases, the UE 115-a may indicate the estimated Doppler metrics by a CSI report to one or both of the TRPs 205. For example, the UE 115-a may transmit a first Doppler shift indication 220-a of the first Doppler shift and a second Doppler shift indication 220-b of the second Doppler shift. In some cases, the UE 115-a may transmit the first Doppler shift indication 220-a to the first TRP 205-a and the second Doppler shift indication 220-b to the second TRP 205-b. In some other cases, the UE 115-a may transmit the first Doppler shift indication 220-a and the second Doppler shift indication 220-b the first TRP 205-a. Here, the first TRP 205-a may communicate the second indication of the second Doppler shift to the second TRP 205-b via a backhaul link 240 between the first TRP 205-a and the second TRP 205-b. In some cases, the UE 115-a may transmit the first Doppler shift indication 220-a and the second Doppler shift indication 220-b based on the backhaul link 240. For example, if the backhaul link 240 is an ideal backhaul link, the UE 115-a may transmit the first Doppler shift indication 220-a and the second Doppler shift indication 220-b to the first TRP 205-a. If the backhaul link 240 is non-ideal, the UE may transmit the first Doppler shift indication 220-a to the first TRP 205-a and the second Doppler shift indication 220-b to the second TRP 205-b. In some instances, the UE 115-a may transmit the first Doppler shift indication 220-a and the second Doppler shift indication 220-b by a physical uplink control channel (PUCCH) or a physical uplink shared channel (PUSCH) .

The UE 115-a may transmit the Doppler shift indications 220 according to a configuration (e.g., indicated by one or both of the TRPs 205) . For example, the UE 115-a may receive DCI from the first TRP 205-a or the second TRP 205-b that indicates a configuration for the Doppler shift indications 220. Additionally, the DCI may indicate a set of resources for transmitting the Doppler shift indications 220 of the estimated Doppler metrics. For example, the UE 115-a may receive DCI configuring the UE 115-a to transmit a first Doppler shift indication 220-a associated with the first Doppler shift and a second Doppler shift indication 220-b associated with the second Doppler shift using resources associated with transmitting one or more CSI reports. That is, the UE 115-a may transmit a CSI report including one or more additional fields corresponding to the first Doppler shift indication 220-a, the second Doppler shift indication 220-b, or both.

The UE 115-a may transmit CSI reports (e.g., including one or both of the Doppler shift indications 220) according to a CSI reporting configurations indicated by DCI. In some cases, the DCI may configure a CSI report with resources associated with each reference signal 210. Additionally, the resources associated with each reference signal 210 may additionally be associated with a TCI state (e.g., the TCI state associated with the reference signal 210) . Here, the UE 115-a may transmit a CSI report including the Doppler shift indication 220-a associated with the first reference signal 210-a, where the Doppler shift indication 220-a additionally indicates the TCI state (e.g., by a first TCI state index) associated with the first reference signal 210-a. Additionally, the UE 115-a may include the Doppler shift indication 220-b associated with the second reference signal 210-b in the CSI report. Here, the Doppler shift indication 220-b may additionally indicate the TCI state (e.g., by a second TCI state index) associated with the second reference signal 210-b.

In other cases, the DCI may configure a CSI report with resources associated with one reference signal 210 (e.g., a third reference signal 210 different from the first reference signal 210-a and the second reference signal 210-b) . Here, the resources associated with the one reference signal 210 may additionally include resources associated with more than one TCI state. For example, the resources associated with the one reference signal 210 may include a first set of resources for the Doppler shift indication 220-a associated with a TCI state corresponding to the first reference signal 210-a. The resources associated with the one reference signal 210 may additionally include a second set of resources for the Doppler shift indication 220-b associated with a different TCI state (e.g., that is associated with the second reference signal 210-b) . Here, the UE 115-a may transmit the first Doppler shift indication 220-a and the second Doppler shift indication 220-b using the resources associated with the one reference signal 210. In order to differentiate between the first Doppler shift indication 220-a and the second Doppler shift indication 220-b, the UE 115-a may transmit the first Doppler shift indication 220-a using the first TCI state index and may transmit the second Doppler shift indication 220-b using the second TCI state index.

In some cases, the DCI configuring the CSI report linked to a reference signal (e.g., a CSI-RS) resource setting (e.g., a resourcesForChannelMeasurement setting) associated with channel measurement. That is, one or more resources associated with the CSI report or the reference signals 210 may be configured for performing or reporting channel measurements (e.g., an RSRP) .

The DCI configuring the Doppler shift indications 220 may indicate, to the UE 115-a, to report an indication of a TRP 205 associated with a reference signal 210 having a higher signal strength than other reference signals 210 received by the UE 115-a. For example, the UE 115-a may determine a signal strength associated with each reference signal 210. The UE 115-a may then identify which of the received reference signals 210 has a higher signal strength (e.g., by comparing an SINR, RSRP, or RSRQ associated with each reference signals 210) . The UE 115-a may then transmit an indication (e.g., in the CSI report) which TRP 205 is associated with the reference signal 210 having the higher signal strength. In some cases, the UE 115-a may be configured to transmit the indication in an additional field of a CSI report by including an index of the reference signal 210 having the higher signal strength.

The DCI configuration may indicate, to the UE 115-a, a quantity of Doppler shift indications 220 to include in the CSI report. That is, the DCI configuration may indicate for the UE 115-a to include the quantity of Doppler shift indications 220 that are associated with the reference signals 210 having the highest signal quality (e.g., the highest SINR, the best RSRP, the best RSRQ) . For example, the DCI configuration may indicate for the UE 115-a to include three the Doppler shift indications 220 in the CSI report that are associated with the three reference signals 210 having the highest signal quality. In another example, the DCI configuration may indicate for the UE 115-a to include a single Doppler shift indication 220 in the CSI report that is associated with the one reference signal 210 having the highest signal quality. In another example, the DCI configuration may indicate for the UE 115-a to include a quantity of Doppler shift indications 220 in the CSI report that is equal to the quantity of TRPs transmitting reference signals 210 to the UE 115-a. Here, the UE 115-a may include Doppler shift indications 220 within the CSI report associated with every reference signal 210 received from the TRPs 205.

After transmitting the one or more Doppler shift indications 220, the UE 115-a may receive Doppler pre-compensated downlink transmissions 230, which may be SFN PDSCH transmissions. In some cases, the first TRP 205-a may Doppler pre-compensate a downlink transmission based on the first Doppler shift indication 220-a and the second TRP may Doppler pre-compensate a downlink transmission based on the second Doppler shift indication 220-b. That is, the first TRP 205-a may adjust a frequency of a of a downlink transmission prior to transmitting the downlink transmission to the UE 115-a to account for the effect of the estimated first Doppler shift associated with the first TRP 205-a. The first TRP 205-a may then transmit the first Doppler pre-compensated downlink transmission 230-a. Additionally, the second TRP 205-b may adjust a frequency of a downlink transmission prior to transmitting the downlink transmission to the UE 115-a to account for the effect of the estimated second Doppler shift associated with the second TRP 205-b. The second TRP 205-b may then transmit the second Doppler pre-compensated downlink transmission 230-b.

The UE 115-a may receive the first Doppler pre-compensated downlink transmission 230-a and the second Doppler pre-compensated downlink transmission 230-b. In some cases, the first Doppler pre-compensated downlink transmission 230-a and the second Doppler pre-compensated downlink transmission 230-b may be SFN PDSCH transmissions. After receiving the Doppler pre-compensated downlink transmissions 230, the UE 115-a may perform a channel estimation procedure on the PDSCH. In some cases, the UE 115-a may select a channel estimation procedure based on an expected Doppler shift associated with the associated with the Doppler pre-compensated downlink transmissions 230. For example, the UE 115-a may select a first channel estimation procedure in a case that a predicated Doppler shift of a downlink transmission exceeds a threshold Doppler shift. Additionally, the UE 115-a may select a second channel estimation procedure in a case that a predicted Doppler shift is less than the threshold Doppler shift. Here, the UE 115-a may select the second channel estimation procedure because the UE 115-a predicts that the Doppler pre-compensated downlink transmissions 230 are Doppler pre-compensated (e.g., based on transmitting the Doppler shift indications 220) and therefore expects the Doppler shift to be less than the threshold Doppler shift. When performing the second channel estimation procedure, the UE 115-a may select a filter size that is less than a filter size associated with the first channel estimation procedure for the Doppler pre-compensated downlink transmission 230 and may average reference signals (e.g., DMRSs) of the Doppler pre-compensated downlink transmissions 230.

FIG. 3 illustrates an example of a process flow 300 that supports Doppler shift reporting for multiple TRPs in accordance with aspects of the present disclosure. In some examples, process flow 300 may implement aspects of wireless communications systems as described with reference to FIGs. 1 and 2. For example, UE 115-b may be an example of the UEs 115 as described with reference to FIGs. 1 and 2. Additionally, base station 105-a may include TRPs 205-c and 205-d that may be examples a base station 105 and TRPs 205 as described with reference to FIGs. 1 and 2.

At 305, the UE 115-b may optionally transmit a UE capability indication to a first TRP 205-c. The UE capability indication may indicate to the first TRP 205-c that the UE 115-b is capable of estimating a first Doppler shift associated with the first TRP 205-c and a second Doppler shift associated with the second TRP 205-d.

At 310, the UE 115-b may optionally transmit a UE capability indication to a second TRP 205-d. That is, the UE 115-b may transmit the UE capability indication to the second TRP 205-d instead of transmitting the UE capability to the first TRP 205-c at 305. In some other cases, the UE 115-b may transmit the UE capability indication to the first TRP 205-c and the second TRP 205-d.

At 315, the first TRP 205-c may optionally transmit DCI that triggers the UE 115-b to estimate Doppler shifts associated with reference signals transmitted by the first TRP 205-c or the second TRP 205-d. The DCI may also indicate a set of resources for transmitting one or more Doppler shift indications to the first TRP 205-c or the second TRP 205-d, or both. In some cases, the DCI may additionally indicate a CSI report configuration for transmitting the Doppler shift indications to one or both of the TRPs 205.

At 320, the second TRP 205-d may optionally transmit DCI that triggers the UE 115-b to estimate Doppler shifts associated with reference signals transmitted by the first TRP 205-c or the second TRP 205-d. For example, the second TRP 205-d may transmit the DCI to the UE 115-b in a case that the first TRP 205-c does not transmit the DCI to the UE 115-b at 315.

At 325, the first TRP 205-c may transmit a reference signal to the UE 115-b. In some cases, the first TRP 205-c may transmit the reference signal based on receiving a UE capability indication indicating that the UE 115-b may estimate a Doppler shift associated with the reference signal. In some cases, the reference signal may be a TRS, an SSB transmission, a CSI-RS, or a combination thereof.

At 330, the second TRP 205-d may transmit a reference signal to the UE 115-b. In some cases, the second TRP 205-d may transmit the reference signal based on receiving a UE capability indication indicating that the UE 115-b may estimate a Doppler shift associated with the reference signal. In some examples, the first TRP 205-c and the second TRP 205-d may be the same TRP 205. Here, the first TRP 205-c may transmit the reference signal from a first RRH of the first TRP 205-c at 325, and the second TRP 205-d may transmit the reference signal from a second RRH of the second TRP 205-d, where the first TRP 205-c and the second TRP 205-d are the same TRP 205. In some cases, the reference signal may be a TRS, an SSB transmission, a CSI-RS, or a combination thereof.

At 335, the UE 115-b may estimate a first Doppler shift associated with the first TRP 205-c and a second Doppler shift associated with the second TRP 205-d. In some cases, the UE 115-b may estimate the first Doppler shift based on the reference signal received at 325. In some cases, the UE may estimate the second Doppler shift based on the reference signal received at 330.

At 340, the UE 115-b may transmit a first Doppler shift indication of the first Doppler shift to the first TRP 205-c. In some cases, the UE 115-b may transmit the first Doppler shift indication as part of a CSI report. The first Doppler shift indication may be associated with a first CORESET index (e.g., based on a TCI state associated with the reference signal transmitted by the first TRP 205-c) .

At 345, the UE 115-b may optionally transmit a second Doppler shift indication to the first TRP 205-c. In some cases, the UE 115-b may transmit the second Doppler shift indications as part of a CSI report. In some cases, the UE 115-b may transmit the second Doppler shift indication to the first TRP 205-c based on a backhaul link between the first TRP 205-c and the second TRP 205-d (e.g., in a case that the first TRP 205-c and the second TRP 205-d are in communication by an ideal backhaul link) . The second Doppler shift indication may be associated with a second CORESET index (e.g., based on a TCI state associated with the reference signal transmitted by the second TRP 205-d) .

At 350, the first TRP 205-c may optionally forward the second indication of the second Doppler shift to the second TRP 205-d (e.g., if the first TRP 205-c receives the second Doppler shift indication from the UE 115-b at 345) . In some cases, the first TRP 205-c may forward the second indication of the second Doppler shift to the second TRP 205-d via a backhaul link between the first TRP 205-c and the second TRP 205-d.

Alternatively, at 355 the UE 115-b may transmit the second indication of the second Doppler shift to the second TRP 205-d. In some instances, the UE 115-b may transmit the second indication of the second Doppler shift to the second TRP 205-d (e.g., instead of the first TRP 205-c) based on a backhaul link between the first TRP 205-c and the second TRP 205-d being non-ideal.

At 360, the first TRP 205-c may Doppler pre-compensate a downlink transmission (e.g., a PDSCH transmission) based on the first Doppler shift indication.

At 365, the second TRP 205-d may Doppler pre-compensate a downlink transmission (e.g., a PDSCH transmission) based on the second Doppler shift indication.

At 370, the first TRP 205-c may transmit a Doppler pre-compensated downlink transmission to the UE 115-b via a PDSCH.

At 375, the second TRP 205-d may transmit a Doppler compensated downlink transmission to the UE 115-b via the PDSCH.

FIG. 4 shows a block diagram 400 of a device 405 that supports Doppler shift reporting for multiple TRPs in accordance with aspects of the present disclosure. The device 405 may be an example of aspects of a UE 115 as described herein. The device 405 may include a receiver 410, a communications manager 415, and a transmitter 420. The device 405 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .

The receiver 410 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to Doppler shift reporting for multiple TRPs, etc. ) . Information may be passed on to other components of the device 405. The receiver 410 may be an example of aspects of the transceiver 720 described with reference to FIG. 7. The receiver 410 may utilize a single antenna or a set of antennas.

The communications manager 415 may receive a first reference signal from a first TRP and a second reference signal from a second TRP, estimate a first Doppler shift associated with the first TRP based on receiving the first reference signal, estimate a second Doppler shift associated with the second TRP based on receiving the second reference signal, and transmit both of a first indication of the first Doppler shift and a second indication of the second Doppler shift, with at least one of the first indication or the second indication being transmitted to at least one of the first TRP or the second TRP . The communications manager 415 may be an example of aspects of the communications manager 710 described herein.

The communications manager 415, or its sub-components, may be implemented in hardware, code (e.g., software or firmware) executed by a processor, or any combination thereof. If implemented in code executed by a processor, the functions of the communications manager 415, or its sub-components may be executed by a general-purpose processor, a digital signal processor (DSP) , an application-specific integrated circuit (ASIC) , a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure.

The communications manager 415, or its sub-components, may be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations by one or more physical components. In some examples, the communications manager 415, or its sub-components, may be a separate and distinct component in accordance with various aspects of the present disclosure. In some examples, the communications manager 415, or its sub-components, may be combined with one or more other hardware components, including but not limited to an input/output (I/O) component, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof in accordance with various aspects of the present disclosure.

The transmitter 420 may transmit signals generated by other components of the device 405. In some examples, the transmitter 420 may be collocated with a receiver 410 in a transceiver module. For example, the transmitter 420 may be an example of aspects of the transceiver 720 described with reference to FIG. 7. The transmitter 420 may utilize a single antenna or a set of antennas.

FIG. 5 shows a block diagram 500 of a device 505 that supports Doppler shift reporting for multiple TRPs in accordance with aspects of the present disclosure. The device 505 may be an example of aspects of a device 405, or a UE 115 as described herein. The device 505 may include a receiver 510, a communications manager 515, and a transmitter 540. The device 505 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .

The receiver 510 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to Doppler shift reporting for multiple TRPs, etc. ) . Information may be passed on to other components of the device 505. The receiver 510 may be an example of aspects of the transceiver 720 described with reference to FIG. 7. The receiver 510 may utilize a single antenna or a set of antennas.

The communications manager 515 may be an example of aspects of the communications manager 415 as described herein. The communications manager 515 may include a reference signal manager 520, a first Doppler shift estimator 525, a second Doppler shift estimator 530, and a Doppler shift indication manager 535. The communications manager 515 may be an example of aspects of the communications manager 710 described herein.

The reference signal manager 520 may receive a first reference signal from a first TRP and a second reference signal from a second TRP.

The first Doppler shift estimator 525 may estimate a first Doppler shift associated with the first TRP based on receiving the first reference signal.

The second Doppler shift estimator 530 may estimate a second Doppler shift associated with the second TRP based on receiving the second reference signal.

The Doppler shift indication manager 535 may transmit both of a first indication of the first Doppler shift and a second indication of the second Doppler shift, with at least one of the first indication or the second indication being transmitted to at least one of the first TRP or the second TRP .

The transmitter 540 may transmit signals generated by other components of the device 505. In some examples, the transmitter 540 may be collocated with a receiver 510 in a transceiver module. For example, the transmitter 540 may be an example of aspects of the transceiver 720 described with reference to FIG. 7. The transmitter 540 may utilize a single antenna or a set of antennas.

FIG. 6 shows a block diagram 600 of a communications manager 605 that supports Doppler shift reporting for multiple TRPs in accordance with aspects of the present disclosure. The communications manager 605 may be an example of aspects of a communications manager 415, a communications manager 515, or a communications manager 710 described herein. The communications manager 605 may include a reference signal manager 610, a first Doppler shift estimator 615, a second Doppler shift estimator 620, a Doppler shift indication manager 625, a Doppler pre-compensation component 630, a UE capability component 635, a DCI component 640, a signal strength component 645, a channel estimation component 650, and an SFN component 655. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses) .

The reference signal manager 610 may receive a first reference signal from a first TRP and a second reference signal from a second TRP. In some examples, the reference signal manager 610 may receive the first reference signal from the first TRP based on a first TCI state. In some cases, the reference signal manager 610 may receive the second reference signal from the second TRP is based on a second TCI state different than the first TCI state. In some instances, the reference signal manager 610 may receive, from a set of TRPs including at least the first TRP and the second TRP, a set of reference signals including at least the first reference signal and the second reference signal.

In some examples, the first reference signal is associated with a first TCI state corresponding to the first TRP. In some cases, the second reference signal is associated with a second TCI state corresponding to the second TRP. In some instances, the first reference signal and the second reference signal are TRSs, CSI-RSs, SSB transmissions, or a combination thereof. In some examples, a set of resources associated with the first reference signal and the second reference signal are configured for a channel measurement procedure.

The first Doppler shift estimator 615 may estimate a first Doppler shift associated with the first TRP based on receiving the first reference signal. In some cases, the first Doppler shift is associated with a first CORESET index.

The second Doppler shift estimator 620 may estimate a second Doppler shift associated with the second TRP based on receiving the second reference signal. In some instances, the second Doppler shift is associated with a second CORESET index.

The Doppler shift indication manager 625 may transmit both of a first indication of the first Doppler shift and a second indication of the second Doppler shift, with at least one of the first indication or the second indication being transmitted to at least one of the first TRP or the second TRP. In some examples, the Doppler shift indication manager 625 may transmit the first indication of the first Doppler shift and the second indication of the second Doppler shift to one of the first TRP or the second TRP. In other examples, the Doppler shift indication manager 625 may transmit the first indication of the first Doppler shift to the first TRP and the second indication of the second Doppler shift to the second TRP.

In some cases, the Doppler shift indication manager 625 may transmit an indication of a TRP, from the first TRP or the second TRP, associated with a reference signal having a higher signal strength.

In some instances, the Doppler shift indication manager 625 may receive an indication of a quantity of Doppler shift indications to transmit to the first TRP or the second TRP, where transmitting the first indication of the first Doppler shift and the second indication of the second Doppler shift is based on receiving the indication of the quantity of Doppler shift indications to transmit. In some examples, the Doppler shift indication manager 625 may transmit the quantity of Doppler shift indications each associated with one of the quantity of reference signals based on identifying a quantity of reference signals of a set of reference signals having a higher signal strength than remaining reference signals of the set of reference signals.

In some cases, the Doppler shift indication manager 625 may transmit a CSI report including the first indication of the first Doppler shift, the second indication of the second Doppler shift, or both. In some instances, the Doppler shift indication manager 625 may transmit the first indication of the first Doppler shift and the second indication of the second Doppler shift by a PUCCH or a PUSCH.

The Doppler pre-compensation component 630 may receive, based on transmitting the first indication of the first Doppler shift, a first Doppler pre-compensated downlink transmission from the first TRP via a PDSCH. In some examples, the Doppler pre-compensation component 630 may receive, based on transmitting the second indication of the second Doppler shift, a second Doppler pre-compensated downlink transmission from the second TRP via the PDSCH. In some cases, the Doppler pre-compensation component 630 may receive, based on transmitting the first indication of the first Doppler shift and the second indication of the second Doppler shift, a first Doppler pre-compensated downlink transmission from the first TRP and a second Doppler pre-compensated downlink transmission from the second TRP.

The UE capability component 635 may transmit an indication of a capability of the UE to estimate the first Doppler shift associated with the first TRP and the second Doppler shift associated with the second TRP, where receiving the first reference signal and the second reference signal is based on transmitting the indication.

The DCI component 640 may receive, from the first TRP or the second TRP, DCI that is indicative of a set of resources for transmitting the first indication and the second indication, where transmitting the first indication and the second indication is based on receiving the DCI. In some cases, the DCI triggers the UE to transmit a CSI report for the first reference signal and the second reference signal. In some instances, the DCI triggers the UE to transmit a CSI report for a single reference signal associated with a first TCI state and a second TCI state. In some cases, the single reference signal associated with the first TCI state corresponds to the first reference signal and the single reference signal associated with the second TCI state corresponds to the second reference signal.

The signal strength component 645 may identify, from the first reference signal and the second reference signal, a reference signal having a higher signal strength. In some instances, the signal strength component 645 may identify a quantity of reference signals of a set of reference signals having a higher signal strength than remaining reference signals of the set of reference signals.

The channel estimation component 650 may select a channel estimation procedure associated with a Doppler shift less than a threshold Doppler shift based on transmitting the first indication of the first Doppler shift and the second indication of the second Doppler shift. In some examples, the channel estimation component 650 may perform the selected channel estimation procedure on a PDSCH based on receiving the first Doppler pre-compensated downlink transmission and the second Doppler pre-compensated downlink transmission.

The SFN component 655 may identify a single frequency network downlink transmission based on receiving the first Doppler pre-compensated downlink transmission and the second Doppler pre-compensated downlink transmission.

FIG. 7 shows a diagram of a system 700 including a device 705 that supports Doppler shift reporting for multiple TRPs in accordance with aspects of the present disclosure. The device 705 may be an example of or include the components of device 405, device 505, or a UE 115 as described herein. The device 705 may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including a communications manager 710, an I/O controller 715, a transceiver 720, an antenna 725, memory 730, and a processor 740. These components may be coupled with each other via one or more buses (e.g., bus 745) .

The communications manager 710 may receive a first reference signal from a first TRP and a second reference signal from a second TRP, estimate a first Doppler shift associated with the first TRP based on receiving the first reference signal, estimate a second Doppler shift associated with the second TRP based on receiving the second reference signal, and transmit both of a first indication of the first Doppler shift and a second indication of the second Doppler shift, with at least one of the first indication or the second indication being transmitted to at least one of the first TRP or the second TRP .

The I/O controller 715 may manage input and output signals for the device 705. The I/O controller 715 may also manage peripherals not integrated into the device 705. In some cases, the I/O controller 715 may represent a physical connection or port to an external peripheral. In some cases, the I/O controller 715 may utilize an operating system such as

or another known operating system. In other cases, the I/O controller 715 may represent or interact with a modem, a keyboard, a mouse, a touchscreen, or a similar device. In some cases, the I/O controller 715 may be implemented as part of a processor. In some cases, a user may interact with the device 705 via the I/O controller 715 or via hardware components controlled by the I/O controller 715.

The transceiver 720 may communicate bi-directionally, via one or more antennas, wired, or wireless links as described above. For example, the transceiver 720 may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver 720 may also include a modem to modulate the packets and provide the modulated packets to the antennas for transmission, and to demodulate packets received from the antennas.

In some cases, the wireless device may include a single antenna 725. However, in some cases the device may have more than one antenna 725, which may be capable of concurrently transmitting or receiving multiple wireless transmissions.

The memory 730 may include random-access memory (RAM) and read-only memory (ROM) . The memory 730 may store computer-readable, computer-executable code 735 including instructions that, when executed, cause the processor to perform various functions described herein. In some cases, the memory 730 may contain, among other things, a basic input/output system (BIOS) which may control basic hardware or software operation such as the interaction with peripheral components or devices.

The processor 740 may include an intelligent hardware device, (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof) . In some cases, the processor 740 may be configured to operate a memory array using a memory controller. In other cases, a memory controller may be integrated into the processor 740. The processor 740 may be configured to execute computer-readable instructions stored in a memory (e.g., the memory 730) to cause the device 705 to perform various functions (e.g., functions or tasks supporting Doppler shift reporting for multiple TRPs) .

The code 735 may include instructions to implement aspects of the present disclosure, including instructions to support wireless communications. The code 735 may be stored in a non-transitory computer-readable medium such as system memory or other type of memory. In some cases, the code 735 may not be directly executable by the processor 740 but may cause a computer (e.g., when compiled and executed) to perform functions described herein.

FIG. 8 shows a block diagram 800 of a device 805 that supports Doppler shift reporting for multiple TRPs in accordance with aspects of the present disclosure. The device 805 may be an example of aspects of a base station 105 as described herein. The device 805 may include a receiver 810, a communications manager 815, and a transmitter 820. The device 805 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .

The receiver 810 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to Doppler shift reporting for multiple TRPs, etc. ) . Information may be passed on to other components of the device 805. The receiver 810 may be an example of aspects of the transceiver 1120 described with reference to FIG. 11. The receiver 810 may utilize a single antenna or a set of antennas.

The communications manager 815 may transmit, by the first TRP, a first reference signal to a UE, transmit, by the second TRP, a second reference signal to the UE, receive, from the UE, a first indication of a first Doppler shift associated with the first TRP based on transmitting the first reference signal, and receive, from the UE, a second indication of a second Doppler shift associated with the second TRP based on transmitting the second reference signal. The communications manager 815 may be an example of aspects of the communications manager 1110 described herein.

The communications manager 815, or its sub-components, may be implemented in hardware, code (e.g., software or firmware) executed by a processor, or any combination thereof. If implemented in code executed by a processor, the functions of the communications manager 815, or its sub-components may be executed by a general-purpose processor, a DSP, an application-specific integrated circuit (ASIC) , a FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure.

The communications manager 815, or its sub-components, may be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations by one or more physical components. In some examples, the communications manager 815, or its sub-components, may be a separate and distinct component in accordance with various aspects of the present disclosure. In some examples, the communications manager 815, or its sub-components, may be combined with one or more other hardware components, including but not limited to an input/output (I/O) component, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof in accordance with various aspects of the present disclosure.

The transmitter 820 may transmit signals generated by other components of the device 805. In some examples, the transmitter 820 may be collocated with a receiver 810 in a transceiver module. For example, the transmitter 820 may be an example of aspects of the transceiver 1120 described with reference to FIG. 11. The transmitter 820 may utilize a single antenna or a set of antennas.

FIG. 9 shows a block diagram 900 of a device 905 that supports Doppler shift reporting for multiple TRPs in accordance with aspects of the present disclosure. The device 905 may be an example of aspects of a device 805, or a base station 105 as described herein. The device 905 may include a receiver 910, a communications manager 915, and a transmitter 940. The device 905 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .

The receiver 910 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to Doppler shift reporting for multiple TRPs, etc. ) . Information may be passed on to other components of the device 905. The receiver 910 may be an example of aspects of the transceiver 1120 described with reference to FIG. 11. The receiver 910 may utilize a single antenna or a set of antennas.

The communications manager 915 may be an example of aspects of the communications manager 815 as described herein. The communications manager 915 may include a first reference signal manager 920, a second reference signal manager 925, a first Doppler shift indication manager 930, and a second Doppler shift indication manager 935. The communications manager 915 may be an example of aspects of the communications manager 1110 described herein.

The first reference signal manager 920 may transmit, by the first TRP, a first reference signal to a UE.

The second reference signal manager 925 may transmit, by the second TRP, a second reference signal to the UE.

The first Doppler shift indication manager 930 may receive, from the UE, a first indication of a first Doppler shift associated with the first TRP based on transmitting the first reference signal.

The second Doppler shift indication manager 935 may receive, from the UE, a second indication of a second Doppler shift associated with the second TRP based on transmitting the second reference signal.

The transmitter 940 may transmit signals generated by other components of the device 905. In some examples, the transmitter 940 may be collocated with a receiver 910 in a transceiver module. For example, the transmitter 940 may be an example of aspects of the transceiver 1120 described with reference to FIG. 11. The transmitter 940 may utilize a single antenna or a set of antennas.

FIG. 10 shows a block diagram 1000 of a communications manager 1005 that supports Doppler shift reporting for multiple TRPs in accordance with aspects of the present disclosure. The communications manager 1005 may be an example of aspects of a communications manager 815, a communications manager 915, or a communications manager 1110 described herein. The communications manager 1005 may include a first reference signal manager 1010, a second reference signal manager 1015, a first Doppler shift indication manager 1020, a second Doppler shift indication manager 1025, a first Doppler pre-compensation component 1030, a second Doppler pre-compensation component 1035, a UE capability component 1040, a DCI component 1045, a signal strength component 1050, and a TRP manager 1055. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses) .

The first reference signal manager 1010 may transmit, by the first TRP, a first reference signal to a UE. In some cases, the first reference signal is associated with a first TCI state corresponding to the first TRP. In some examples, the first reference signal manager 1010 may transmit the first reference signal from the first TRP based on a first TCI state.

In some instances, the first reference signal is a TRS, CSI-RS, SSB transmission, or a combination thereof. In some examples, a set of resources associated with the first reference signal and a second reference signal are configured for a channel measurement procedure.

The second reference signal manager 1015 may transmit, by the second TRP, a second reference signal to the UE. In some cases, the second reference signal is associated with a second TCI state corresponding to the second TRP. In some cases, the second reference signal manager 1015 may transmit the second reference signal from the second TRP based on a second TCI state different than the first TCI state.

In some instances, the second reference signal is a TRS, CSI-RS, SSB transmission, or a combination thereof. In some cases, a set of resources associated with a first reference signal and the second reference signal are configured for a channel measurement procedure.

The first Doppler shift indication manager 1020 may receive, from the UE, a first indication of a first Doppler shift associated with the first TRP based on transmitting the first reference signal. In some instances, the first Doppler shift indication manager 1020 may receive, by the first TRP, the first indication of the first Doppler shift. In some examples, the first Doppler shift indication manager 1020 may receive, by the first TRP, the first indication of the first Doppler shift and a second indication of a second Doppler shift. In some cases, the first Doppler shift indication manager 1020 may transmit, to the UE, an indication of a quantity of Doppler shift indications for the UE transmit to the first TRP or the second TRP, where receiving the first indication of the first Doppler shift and the second indication of the second Doppler shift is based on transmitting the indication of the quantity of Doppler shift indications to the UE

In some examples, the first Doppler shift indication manager 1020 may receive a CSI report including the first indication of the first Doppler shift, the second indication of the second Doppler shift, or both. In some examples, the first Doppler shift indication manager 1020 may receive the first indication of the first Doppler shift and the second indication of the second Doppler shift by a PUCCH or a PUSCH. In some cases, the first Doppler shift is associated with a first CORESET index.

The second Doppler shift indication manager 1025 may receive, from the UE, a second indication of a second Doppler shift associated with the second TRP based on transmitting the second reference signal. In some examples, the second Doppler shift indication manager 1025 may receive, by the second TRP, the second indication of the second Doppler shift. In some cases, the second Doppler shift indication manager 1025 may receive, by the second TRP, a first indication of a first Doppler shift and the second indication of the second Doppler shift. In some instances, the second Doppler shift indication manager 1025 may transmit, to the UE, an indication of a quantity of Doppler shift indications for the UE transmit to the first TRP or the second TRP, where receiving the first indication of the first Doppler shift and the second indication of the second Doppler shift is based on transmitting the indication of the quantity of Doppler shift indications to the UE.

In some examples, the second Doppler shift indication manager 1025 may receive a CSI report including the first indication of the first Doppler shift, the second indication of the second Doppler shift, or both. In some cases, the second Doppler shift indication manager 1025 may receive the first indication of the first Doppler shift and the second indication of the second Doppler shift by a PUCCH or a PUSCH. In some instances, the second Doppler shift is associated with a second CORESET index.

The first Doppler pre-compensation component 1030 may transmit, based on receiving the first indication of the first Doppler shift, a first Doppler pre-compensated downlink transmission from the first TRP to the UE via a PDSCH.

The second Doppler pre-compensation component 1035 may transmit, based on receiving the second indication of the second Doppler shift, a second Doppler pre-compensated downlink transmission from the second TRP to the UE via the PDSCH.

The UE capability component 1040 may receive an indication of a capability of the UE to estimate the first Doppler shift associated with the first TRP and the second Doppler shift associated with the second TRP, where transmitting the first reference signal and the second reference signal is based on receiving the indication.

The DCI component 1045 may transmit, by the first TRP or the second TRP, DCI that is indicative of a set of resources for transmitting the first indication and the second indication, where receiving the first indication and the second indication is based on transmitting the DCI. In some cases, the DCI triggers the UE to transmit a CSI report corresponding to the first reference signal and the second reference signal. In some examples, the DCI triggers the UE to transmit a CSI report for the first reference signal and the second reference signal. In some instances, the DCI triggers the UE to transmit a CSI report for a single reference signal associated with a first TCI state and a second TCI state. In some examples, the single reference signal associated with the first TCI state corresponds to the first reference signal and the single reference signal associated with the second TCI state corresponds to the second reference signal

The signal strength component 1050 may receive, from the UE based on transmitting the first reference signal and the second reference signal, an indication of a TRP, from the first TRP or the second TRP, associated with a reference signal having a higher signal strength.

The TRP manager 1055 may transmit, by a set of TRPs including at least the first TRP and the second TRP, a set of reference signals to the UE, the set of reference signals including at least the first reference signal and the second reference signal. In some examples, the TRP manager 1055 may receive a quantity of Doppler shift indications each associated with one of the quantity of reference signals of the set of reference signals having a higher signal strength than remaining reference signals of the set of reference signals.

FIG. 11 shows a diagram of a system 1100 including a device 1105 that supports Doppler shift reporting for multiple TRPs in accordance with aspects of the present disclosure. The device 1105 may be an example of or include the components of device 805, device 905, or a base station 105 as described herein. The device 1105 may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including a communications manager 1110, a network communications manager 1115, a transceiver 1120, an antenna 1125, memory 1130, a processor 1140, and an inter-station communications manager 1145. These components may be coupled with each other via one or more buses (e.g., bus 1150) .

The communications manager 1110 may transmit, by the first TRP, a first reference signal to a UE, transmit, by the second TRP, a second reference signal to the UE, receive, from the UE, a first indication of a first Doppler shift associated with the first TRP based on transmitting the first reference signal, and receive, from the UE, a second indication of a second Doppler shift associated with the second TRP based on transmitting the second reference signal.

The network communications manager 1115 may manage communications with the core network (e.g., via one or more wired backhaul links) . For example, the network communications manager 1115 may manage the transfer of data communications for client devices, such as one or more UEs 115.

The transceiver 1120 may communicate bi-directionally, via one or more antennas, wired, or wireless links as described above. For example, the transceiver 1120 may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver 1120 may also include a modem to modulate the packets and provide the modulated packets to the antennas for transmission, and to demodulate packets received from the antennas.

In some cases, the wireless device may include a single antenna 1125. However, in some cases the device may have more than one antenna 1125, which may be capable of concurrently transmitting or receiving multiple wireless transmissions.

The memory 1130 may include RAM, ROM, or a combination thereof. The memory 1130 may store computer-readable code 1135 including instructions that, when executed by a processor (e.g., the processor 1140) cause the device to perform various functions described herein. In some cases, the memory 1130 may contain, among other things, a BIOS which may control basic hardware or software operation such as the interaction with peripheral components or devices.

The processor 1140 may include an intelligent hardware device, (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof) . In some cases, the processor 1140 may be configured to operate a memory array using a memory controller. In some cases, a memory controller may be integrated into processor 1140. The processor 1140 may be configured to execute computer-readable instructions stored in a memory (e.g., the memory 1130) to cause the device 1105 to perform various functions (e.g., functions or tasks supporting Doppler shift reporting for multiple TRPs) .

The inter-station communications manager 1145 may manage communications with other base station 105, and may include a controller or scheduler for controlling communications with UEs 115 in cooperation with other base stations 105. For example, the inter-station communications manager 1145 may coordinate scheduling for transmissions to UEs 115 for various interference mitigation techniques such as beamforming or joint transmission. In some examples, the inter-station communications manager 1145 may provide an X2 interface within an LTE/LTE-A wireless communication network technology to provide communication between base stations 105.

The code 1135 may include instructions to implement aspects of the present disclosure, including instructions to support wireless communications. The code 1135 may be stored in a non-transitory computer-readable medium such as system memory or other type of memory. In some cases, the code 1135 may not be directly executable by the processor 1140 but may cause a computer (e.g., when compiled and executed) to perform functions described herein.

FIG. 12 shows a flowchart illustrating a method 1200 that supports Doppler shift reporting for multiple TRPs in accordance with aspects of the present disclosure. The operations of method 1200 may be implemented by a UE 115 or its components as described herein. For example, the operations of method 1200 may be performed by a communications manager as described with reference to FIGs. 4 through 7. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware.

At 1205, the UE may receive a first reference signal from a first TRP and a second reference signal from a second TRP. The operations of 1205 may be performed according to the methods described herein. In some examples, aspects of the operations of 1205 may be performed by a reference signal manager as described with reference to FIGs. 4 through 7.

At 1210, the UE may estimate a first Doppler shift associated with the first TRP based on receiving the first reference signal. The operations of 1210 may be performed according to the methods described herein. In some examples, aspects of the operations of 1210 may be performed by a first Doppler shift estimator as described with reference to FIGs. 4 through 7.

At 1215, the UE may estimate a second Doppler shift associated with the second TRP based on receiving the second reference signal. The operations of 1215 may be performed according to the methods described herein. In some examples, aspects of the operations of 1215 may be performed by a second Doppler shift estimator as described with reference to FIGs. 4 through 7.

At 1220, the UE may transmit both of a first indication of the first Doppler shift and a second indication of the second Doppler shift, with at least one of the first indication or the second indication being transmitted to at least one of the first TRP or the second TRP . The operations of 1220 may be performed according to the methods described herein. In some examples, aspects of the operations of 1220 may be performed by a Doppler shift indication manager as described with reference to FIGs. 4 through 7.

FIG. 13 shows a flowchart illustrating a method 1300 that supports Doppler shift reporting for multiple TRPs in accordance with aspects of the present disclosure. The operations of method 1300 may be implemented by a UE 115 or its components as described herein. For example, the operations of method 1300 may be performed by a communications manager as described with reference to FIGs. 4 through 7. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware.

At 1305, the UE may receive a first reference signal from a first TRP and a second reference signal from a second TRP. The operations of 1305 may be performed according to the methods described herein. In some examples, aspects of the operations of 1305 may be performed by a reference signal manager as described with reference to FIGs. 4 through 7.

At 1310, the UE may estimate a first Doppler shift associated with the first TRP based on receiving the first reference signal. The operations of 1310 may be performed according to the methods described herein. In some examples, aspects of the operations of 1310 may be performed by a first Doppler shift estimator as described with reference to FIGs. 4 through 7.

At 1315, the UE may estimate a second Doppler shift associated with the second TRP based on receiving the second reference signal. The operations of 1315 may be performed according to the methods described herein. In some examples, aspects of the operations of 1315 may be performed by a second Doppler shift estimator as described with reference to FIGs. 4 through 7.

At 1320, the UE may transmit both of a first indication of the first Doppler shift and a second indication of the second Doppler shift, with at least one of the first indication or the second indication being transmitted to at least one of the first TRP or the second TRP . The operations of 1320 may be performed according to the methods described herein. In some examples, aspects of the operations of 1320 may be performed by a Doppler shift indication manager as described with reference to FIGs. 4 through 7.

At 1325, the UE may receive, based on transmitting the first indication of the first Doppler shift, a first Doppler pre-compensated downlink transmission from the first TRP via a PDSCH. The operations of 1325 may be performed according to the methods described herein. In some examples, aspects of the operations of 1325 may be performed by a Doppler pre-compensation component as described with reference to FIGs. 4 through 7.

At 1330, the UE may receive, based on transmitting the second indication of the second Doppler shift, a second Doppler pre-compensated downlink transmission from the second TRP via the PDSCH. The operations of 1330 may be performed according to the methods described herein. In some examples, aspects of the operations of 1330 may be performed by a Doppler pre-compensation component as described with reference to FIGs. 4 through 7.

FIG. 14 shows a flowchart illustrating a method 1400 that supports Doppler shift reporting for multiple TRPs in accordance with aspects of the present disclosure. The operations of method 1400 may be implemented by a base station 105 or its components as described herein. For example, the operations of method 1400 may be performed by a communications manager as described with reference to FIGs. 8 through 11. In some examples, a base station may execute a set of instructions to control the functional elements of the base station to perform the functions described below. Additionally or alternatively, a base station may perform aspects of the functions described below using special-purpose hardware.

At 1405, the base station may transmit, by the first TRP, a first reference signal to a UE. The operations of 1405 may be performed according to the methods described herein. In some examples, aspects of the operations of 1405 may be performed by a first reference signal manager as described with reference to FIGs. 8 through 11.

At 1410, the base station may transmit, by the second TRP, a second reference signal to the UE. The operations of 1410 may be performed according to the methods described herein. In some examples, aspects of the operations of 1410 may be performed by a second reference signal manager as described with reference to FIGs. 8 through 11.

At 1415, the base station may receive, from the UE, a first indication of a first Doppler shift associated with the first TRP based on transmitting the first reference signal. The operations of 1415 may be performed according to the methods described herein. In some examples, aspects of the operations of 1415 may be performed by a first Doppler shift indication manager as described with reference to FIGs. 8 through 11.

At 1420, the base station may receive, from the UE, a second indication of a second Doppler shift associated with the second TRP based on transmitting the second reference signal. The operations of 1420 may be performed according to the methods described herein. In some examples, aspects of the operations of 1420 may be performed by a second Doppler shift indication manager as described with reference to FIGs. 8 through 11.

FIG. 15 shows a flowchart illustrating a method 1500 that supports Doppler shift reporting for multiple TRPs in accordance with aspects of the present disclosure. The operations of method 1500 may be implemented by a base station 105 or its components as described herein. For example, the operations of method 1500 may be performed by a communications manager as described with reference to FIGs. 8 through 11. In some examples, a base station may execute a set of instructions to control the functional elements of the base station to perform the functions described below. Additionally or alternatively, a base station may perform aspects of the functions described below using special-purpose hardware.

At 1505, the base station may transmit, by the first TRP, a first reference signal to a UE. The operations of 1505 may be performed according to the methods described herein. In some examples, aspects of the operations of 1505 may be performed by a first reference signal manager as described with reference to FIGs. 8 through 11.

At 1510, the base station may transmit, by the second TRP, a second reference signal to the UE. The operations of 1510 may be performed according to the methods described herein. In some examples, aspects of the operations of 1510 may be performed by a second reference signal manager as described with reference to FIGs. 8 through 11.

At 1515, the base station may receive, from the UE, a first indication of a first Doppler shift associated with the first TRP based on transmitting the first reference signal. The operations of 1515 may be performed according to the methods described herein. In some examples, aspects of the operations of 1515 may be performed by a first Doppler shift indication manager as described with reference to FIGs. 8 through 11.

At 1520, the base station may receive, from the UE, a second indication of a second Doppler shift associated with the second TRP based on transmitting the second reference signal. The operations of 1520 may be performed according to the methods described herein. In some examples, aspects of the operations of 1520 may be performed by a second Doppler shift indication manager as described with reference to FIGs. 8 through 11.

At 1525, the base station may transmit, based on receiving the first indication of the first Doppler shift, a first Doppler pre-compensated downlink transmission from the first TRP to the UE via a PDSCH. The operations of 1525 may be performed according to the methods described herein. In some examples, aspects of the operations of 1525 may be performed by a first Doppler pre-compensation component as described with reference to FIGs. 8 through 11.

At 1530, the base station may transmit, based on receiving the second indication of the second Doppler shift, a second Doppler pre-compensated downlink transmission from the second TRP to the UE via the PDSCH. The operations of 1530 may be performed according to the methods described herein. In some examples, aspects of the operations of 1530 may be performed by a second Doppler pre-compensation component as described with reference to FIGs. 8 through 11.

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

The following provides an overview of examples of the present disclosure:

Example 1: A method for wireless communication at a user equipment (UE) , comprising: receiving a first reference signal from a first TRP and a second reference signal from a second TRP; estimating a first Doppler shift associated with the first TRP based at least in part on receiving the first reference signal; estimating a second Doppler shift associated with the second TRP based at least in part on receiving the second reference signal; and transmitting both of a first indication of the first Doppler shift and a second indication of the second Doppler shift, with at least one of the first indication or the second indication being transmitted to at least one of the first TRP or the second TRP.

Example 2: The method of example 1, further comprising: receiving, based at least in part on transmitting the first indication of the first Doppler shift, a first Doppler pre-compensated downlink transmission from the first TRP via a PDSCH; and receiving, based at least in part on transmitting the second indication of the second Doppler shift, a second Doppler pre-compensated downlink transmission from the second TRP via the PDSCH.

Example 3: The method of any one of examples 1 through 2, further comprising: transmitting an indication of a capability of the UE to estimate the first Doppler shift associated with the first TRP and the second Doppler shift associated with the second TRP, wherein receiving the first reference signal and the second reference signal is based at least in part on transmitting the indication.

Example 4: The method of any one of examples 1 through 3, further comprising: receiving, from the first TRP or the second TRP, DCI that is indicative of a set of resources for transmitting the first indication and the second indication, wherein transmitting the first indication and the second indication is based at least in part on receiving the DCI.

Example 5: The method of example 4, wherein: the DCI triggers the UE to transmit a channel state information report corresponding to one or more reference signals transmitted by one of the first TRP or the second TRP; and the one or more reference signals include one of the first reference signal or the second reference signal and are associated with unique TCI states of one of the first TRP or the second TRP.

Example 6: The method of any one of examples 4 through 5, wherein: the DCI triggers the UE to transmit a channel state information report corresponding to the first reference signal and the second reference signal; the first reference signal is associated with a first TCI state; and the second reference signal is associated with a second TCI state.

Example 7: The method of any one of examples 1 through 6, further comprising: identifying, from the first reference signal and the second reference signal, a reference signal having a higher signal strength; and transmitting an indication of a TRP, from the first TRP or the second TRP, associated with the reference signal having the higher signal strength.

Example 8: The method of any one of examples 1 through 7, further comprising: receiving an indication of a quantity of Doppler shift indications to transmit to the first TRP or the second TRP, wherein transmitting the first indication of the first Doppler shift and the second indication of the second Doppler shift is based at least in part on receiving the indication of the quantity of Doppler shift indications to transmit.

Example 9: The method of any one of examples 1 through 8, further comprising: receiving, from a set of TRPs comprising at least the first TRP and the second TRP, a set of reference signals comprising at least the first reference signal and the second reference signal; identifying the quantity of reference signals of the set of reference signals having a higher signal strength than remaining reference signals of the set of reference signals; and transmitting the quantity of Doppler shift indications each associated with one of the quantity of reference signals based at least in part on the identifying.

Example 10: The method of any one of examples 1 through 9, wherein transmitting the first indication of the first Doppler shift and the second indication of the second Doppler shift comprises: transmitting the first indication of the first Doppler shift and the second indication of the second Doppler shift to one of the first TRP or the second TRP.

Example 11: The method of any one of examples 1 through 10, wherein transmitting the first indication of the first Doppler shift and the second indication of the second Doppler shift comprises: transmitting the first indication of the first Doppler shift to the first TRP; and transmitting the second indication of the second Doppler shift to the second TRP.

Example 12: The method of any one of examples 1 through 11, wherein transmitting the first indication and the second indication further comprises: transmitting a channel state information report comprising the first indication of the first Doppler shift, the second indication of the second Doppler shift, or both.

Example 13: The method of any one of examples 1 through 12, wherein transmitting the first indication and the second indication further comprises: transmitting the first indication of the first Doppler shift and the second indication of the second Doppler shift by a PUCCH or a PUSCH.

Example 14: The method of any one of examples 1 through 13, further comprising: receiving, based at least in part on transmitting the first indication of the first Doppler shift and the second indication of the second Doppler shift, a first Doppler pre-compensated downlink transmission from the first TRP and a second Doppler pre-compensated downlink transmission from the second TRP; selecting a channel estimation procedure associated with a Doppler shift less than a threshold Doppler shift based at least in part on transmitting the first indication of the first Doppler shift and the second indication of the second Doppler shift; and performing the selected channel estimation procedure on a PDSCH based at least in part on receiving the first Doppler pre-compensated downlink transmission and the second Doppler pre-compensated downlink transmission.

Example 15: The method of any one of examples 1 through 14, further comprising: receiving, based at least in part on transmitting the first indication of the first Doppler shift and the second indication of the second Doppler shift, a first Doppler pre-compensated downlink transmission from the first TRP and a second Doppler pre-compensated downlink transmission from the second TRP; and identifying a single frequency network downlink transmission based at least in part on receiving the first Doppler pre-compensated downlink transmission and the second Doppler pre-compensated downlink transmission.

Example 16: The method of any one of examples 1 through 15, wherein receiving the first reference signal from the first TRP and the second reference signal from the second TRP comprises: receiving the first reference signal from a first RRH of the first TRP; and receiving the second reference signal from a second RRH of the second TRP, wherein the first TRP and the second TRP are the same.

Example 17: The method of any one of examples 1 through 16, wherein the first reference signal and the second reference signal are TRSs, CSI-RSs, SSB transmissions, or a combination thereof.

Example 18: The method of any one of examples 1 through 17, wherein: the first reference signal and the second reference signal are CSI-RSs; and a set of resources associated with the first reference signal and the second reference signal are configured for a channel measurement procedure.

Example 19: The method of any one of examples 1 through 18, wherein: receiving the first reference signal from the first TRP is based at least in part on a first TCI state; and receiving the second reference signal from the second TRP is based at least in part on a second TCI state different than the first TCI state.

Example 20: The method of any one of examples 1 through 19, wherein: the first Doppler shift is associated with a first CORESET index; and the second Doppler shift is associated with a second CORESET index.

Example 21: A method for wireless communication at a cell associated with a first TRP and a second TRP, comprising: transmitting, by the first TRP, a first reference signal to a user equipment (UE) ; transmitting, by the second TRP, a second reference signal to the UE; receiving, from the UE, a first indication of a first Doppler shift associated with the first TRP based at least in part on transmitting the first reference signal; and receiving, from the UE, a second indication of a second Doppler shift associated with the second TRP based at least in part on transmitting the second reference signal.

Example 22: The method of example 21, further comprising: transmitting, based at least in part on receiving the first indication of the first Doppler shift, a first Doppler pre-compensated downlink transmission from the first TRP to the UE via a PDSCH; and transmitting, based at least in part on receiving the second indication of the second Doppler shift, a second Doppler pre-compensated downlink transmission from the second TRP to the UE via the PDSCH.

Example 23: The method of any one of examples 21 through 22, further comprising: receiving an indication of a capability of the UE to estimate the first Doppler shift associated with the first TRP and the second Doppler shift associated with the second TRP, wherein transmitting the first reference signal and the second reference signal is based at least in part on receiving the indication.

Example 24: The method of any one of examples 21 through 23, further comprising: transmitting, by the first TRP or the second TRP, DCI that is indicative of a set of resources for transmitting the first indication and the second indication, wherein receiving the first indication and the second indication is based at least in part on transmitting the DCI.

Example 25: The method of example 24, wherein: the DCI triggers the UE to transmit a channel state information report corresponding to one or more reference signals transmitted by one of the first TRP or the second TRP; and the one or more reference signals include one of the first reference signal or the second reference signal and are associated with unique TCI states of one of the first TRP or the second TRP.

Example 26: The method of any one of examples 24 through 25 wherein: the DCI triggers the UE to transmit a channel state information report corresponding to the first reference signal and the second reference signal; the first reference signal is associated with a first TCI state; and the second reference signal is associated with a second TCI state.

Example 27: The method of any one of examples 21 through 26, further comprising: receiving, from the UE based at least in part on transmitting the first reference signal and the second reference signal, an indication of a TRP, from the first TRP or the second TRP, associated with a reference signal having a higher signal strength.

Example 28: The method of any one of examples 21 through 27, further comprising: transmitting, to the UE, an indication of a quantity of Doppler shift indications for the UE transmit to the first TRP or the second TRP, wherein receiving the first indication of the first Doppler shift and the second indication of the second Doppler shift is based at least in part on transmitting the indication of the quantity of Doppler shift indications to the UE.

Example 29: The method of any one of examples 21 through 28, further comprising: transmitting, by a set of TRPs comprising at least the first TRP and the second TRP, a set of reference signals to the UE, the set of reference signals comprising at least the first reference signal and the second reference signal; and receiving the quantity of Doppler shift indications each associated with one of the quantity of reference signals of the set of reference signals having a higher signal strength than remaining reference signals of the set of reference signals.

Example 30: The method of any one of examples 21 through 29, wherein receiving the first indication of the first Doppler shift and the second indication of the second Doppler shift comprises: receiving, by one of the first TRP or the second TRP, the first indication of the first Doppler shift and the second indication of the second Doppler shift.

Example 31: The method of any one of examples 21 through 30, wherein receiving the first indication of the first Doppler shift and the second indication of the second Doppler shift comprises: receiving, by the first TRP, the first indication of the first Doppler shift; and receiving, by the second TRP, the second indication of the second Doppler shift.

Example 32: The method of any one of examples 21 through 31, wherein receiving the first indication of the first Doppler shift and the second indication of the second Doppler shift comprises: receiving a channel state information report comprising the first indication of the first Doppler shift, the second indication of the second Doppler shift, or both.

Example 33: The method of any one of examples 21 through 32, wherein receiving the first indication of the first Doppler shift and the second indication of the second Doppler shift comprises: receiving the first indication of the first Doppler shift and the second indication of the second Doppler shift by a PUCCH or a PUSCH.

Example 34: The method of any one of examples 21 through 33, wherein transmitting the first reference signal and the second reference signal comprises: transmitting the first reference signal to the UE by a first RRH of the first TRP; and transmitting the second reference signal the UE by a second RRH of the second TRP, wherein the first TRP and the second TRP are the same.

Example 35: The method of any one of examples 21 through 34, wherein the first reference signal and the second reference signal are TRSs, CSI-RSs, SSB transmissions, or a combination thereof.

Example 36: The method of any one of examples 21 through 35, wherein: the first reference signal and the second reference signal are CSI-RSs; and a set of resources associated with the first reference signal and the second reference signal are configured for a channel measurement procedure.

Example 37: The method of any one of examples 21 through 36, wherein: transmitting the first reference signal from the first TRP is based at least in part on a first TCI state; and transmitting the second reference signal from the second TRP is based at least in part on a second TCI state different than the first TCI state.

Example 38: The method of any one of examples 21 through 37, wherein: the first Doppler shift is associated with a first CORESET index; and the second Doppler shift is associated with a second CORESET index.

Example 39: An apparatus for wireless communications at a UE comprising at least one means for performing a method of any one of examples 1 through 20.

Example 40: An apparatus for wireless communications at a UE comprising: a processor; memory coupled to the processor; and instructions stored in the memory and executable to perform a method of any one of examples 1 through 20.

Example 41: A non-transitory computer-readable medium storing code for wireless communications at a UE, the code comprising instructions executable by a processor to perform a method of any one of examples 1 through 20.

Example 42: An apparatus for wireless communications at a cell associated with a first TRP and a second TRP comprising at least one means for performing a method of any one of examples 21 through 38

Example 43: An apparatus for wireless communication at a cell associated with a first TRP and a second TRP, comprising: a processor; memory coupled to the processor; and instructions stored in the memory and executable to perform a method of any one of examples 21 through 38.

Example 44: A non-transitory computer-readable medium storing code for wireless communications at a cell associated with a first TRP and a second TRP, the code comprising instructions executable by a processor to perform a method of any one of examples 21 through 38.

Although aspects of an LTE, LTE-A, LTE-A Pro, or NR system may be described for purposes of example, and LTE, LTE-A, LTE-A Pro, or NR terminology may be used in much of the description, the techniques described herein are applicable beyond LTE, LTE-A, LTE-A Pro, or NR networks. For example, the described techniques may be applicable to various other wireless communications systems such as Ultra Mobile Broadband (UMB) , Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi) , IEEE 802.16 (WiMAX) , IEEE 802.20, Flash-OFDM, as well as other systems and radio technologies not explicitly mentioned herein.

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

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

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

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

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

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

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

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

Claims

A method for wireless communication at a user equipment (UE) , comprising:

receiving a first reference signal from a first transmission reception point and a second reference signal from a second transmission reception point;

estimating a first Doppler shift associated with the first transmission reception point based at least in part on receiving the first reference signal;

estimating a second Doppler shift associated with the second transmission reception point based at least in part on receiving the second reference signal; and

transmitting both of a first indication of the first Doppler shift and a second indication of the second Doppler shift, with at least one of the first indication or the second indication being transmitted to at least one of the first transmission reception point or the second transmission reception point.
The method of claim 1, further comprising:

receiving, based at least in part on transmitting the first indication of the first Doppler shift, a first Doppler pre-compensated downlink transmission from the first transmission reception point via a physical downlink shared channel; and

receiving, based at least in part on transmitting the second indication of the second Doppler shift, a second Doppler pre-compensated downlink transmission from the second transmission reception point via the physical downlink shared channel.
The method of claim 1, further comprising; .

transmitting an indication of a capability of the UE to estimate the first Doppler shift associated with the first transmission reception point and the second Doppler shift associated with the second transmission reception point, wherein receiving the first reference signal and the second reference signal is based at least in part on transmitting the indication.
The method of claim 1, further comprising:

receiving, from the first transmission reception point or the second transmission reception point, downlink control information that is indicative of a set of resources for transmitting the first indication and the second indication, wherein transmitting the first indication and the second indication is based at least in part on receiving the downlink control information.
The method of claim 4, wherein:

the downlink control information triggers the UE to transmit a channel state information report corresponding to one or more reference signals transmitted by one of the first transmission reception point or the second transmission reception point; and

the one or more reference signals include one of the first reference signal or the second reference signal and are associated with unique transmission configuration indicator states of one of the first transmission reception point or the second transmission reception point.
The method of claim 4, wherein:

the downlink control information triggers the UE to transmit a channel state information report corresponding to the first reference signal and the second reference signal;

the first reference signal is associated with a first transmission configuration indicator state; and

the second reference signal is associated with a second transmission configuration indicator state.
The method of claim 1, further comprising:

identifying, from the first reference signal and the second reference signal, a reference signal having a higher signal strength; and

transmitting an indication of a transmission reception point, from the first transmission reception point or the second transmission reception point, associated with the reference signal having the higher signal strength.
The method of claim 1, further comprising:

receiving an indication of a quantity of Doppler shift indications to transmit to the first transmission reception point or the second transmission reception point, wherein transmitting the first indication of the first Doppler shift and the second indication of the second Doppler shift is based at least in part on receiving the indication of the quantity of Doppler shift indications to transmit.
The method of claim 8, further comprising:

receiving, from a set of transmission reception points comprising at least the first transmission reception point and the second transmission reception point, a set of reference signals comprising at least the first reference signal and the second reference signal;

identifying the quantity of reference signals of the set of reference signals having a higher signal strength than remaining reference signals of the set of reference signals; and

transmitting the quantity of Doppler shift indications each associated with one of the quantity of reference signals based at least in part on the identifying.
The method of claim 1, wherein transmitting the first indication of the first Doppler shift and the second indication of the second Doppler shift comprises:

transmitting the first indication of the first Doppler shift and the second indication of the second Doppler shift to one of the first transmission reception point or the second transmission reception point.
The method of claim 1, wherein transmitting the first indication of the first Doppler shift and the second indication of the second Doppler shift comprises:

transmitting the first indication of the first Doppler shift to the first transmission reception point; and

transmitting the second indication of the second Doppler shift to the second transmission reception point.
The method of claim 1, wherein transmitting the first indication and the second indication further comprises:

transmitting a channel state information report comprising the first indication of the first Doppler shift, the second indication of the second Doppler shift, or both.
The method of claim 1, wherein transmitting the first indication and the second indication further comprises:

transmitting the first indication of the first Doppler shift and the second indication of the second Doppler shift by a physical uplink control channel or a physical uplink shared channel.
The method of claim 1, further comprising:

receiving, based at least in part on transmitting the first indication of the first Doppler shift and the second indication of the second Doppler shift, a first Doppler pre-compensated downlink transmission from the first transmission reception point and a second Doppler pre-compensated downlink transmission from the second transmission reception point;

selecting a channel estimation procedure associated with a Doppler shift less than a threshold Doppler shift based at least in part on transmitting the first indication of the first Doppler shift and the second indication of the second Doppler shift; and

performing the selected channel estimation procedure on a physical downlink shared channel based at least in part on receiving the first Doppler pre-compensated downlink transmission and the second Doppler pre-compensated downlink transmission.
The method of claim 1, further comprising:

receiving, based at least in part on transmitting the first indication of the first Doppler shift and the second indication of the second Doppler shift, a first Doppler pre-compensated downlink transmission from the first transmission reception point and a second Doppler pre-compensated downlink transmission from the second transmission reception point; and

identifying a single frequency network downlink transmission based at least in part on receiving the first Doppler pre-compensated downlink transmission and the second Doppler pre-compensated downlink transmission.
The method of claim 1, wherein receiving the first reference signal from the first transmission reception point and the second reference signal from the second transmission reception point comprises:

receiving the first reference signal from a first remote radio head of the first transmission reception point; and

receiving the second reference signal from a second remote radio head of the second transmission reception point, wherein the first transmission reception point and the second transmission reception point are the same.
The method of claim 1, wherein the first reference signal and the second reference signal are tracking reference signals, channel state information reference signals, synchronization signal block transmissions, or a combination thereof.
The method of claim 1, wherein:

the first reference signal and the second reference signal are channel state information reference signals; and

a set of resources associated with the first reference signal and the second reference signal are configured for a channel measurement procedure.
The method of claim 1, wherein:

receiving the first reference signal from the first transmission reception point is based at least in part on a first transmission configuration indicator state; and

receiving the second reference signal from the second transmission reception point is based at least in part on a second transmission configuration indicator state different than the first transmission configuration indicator state.
The method of claim 1, wherein:

the first Doppler shift is associated with a first control resource set index; and

the second Doppler shift is associated with a second control resource set index.
A method for wireless communication at a cell associated with a first transmission reception point and a second transmission reception point, comprising:

transmitting, by the first transmission reception point, a first reference signal to a user equipment (UE) ;

transmitting, by the second transmission reception point, a second reference signal to the UE;

receiving, from the UE, a first indication of a first Doppler shift associated with the first transmission reception point based at least in part on transmitting the first reference signal; and

receiving, from the UE, a second indication of a second Doppler shift associated with the second transmission reception point based at least in part on transmitting the second reference signal.
The method of claim 21, further comprising:

transmitting, based at least in part on receiving the first indication of the first Doppler shift, a first Doppler pre-compensated downlink transmission from the first transmission reception point to the UE via a physical downlink shared channel; and

transmitting, based at least in part on receiving the second indication of the second Doppler shift, a second Doppler pre-compensated downlink transmission from the second transmission reception point to the UE via the physical downlink shared channel.
The method of claim 21, further comprising:

receiving an indication of a capability of the UE to estimate the first Doppler shift associated with the first transmission reception point and the second Doppler shift associated with the second transmission reception point, wherein transmitting the first reference signal and the second reference signal is based at least in part on receiving the indication.
The method of claim 21, further comprising:

transmitting, by the first transmission reception point or the second transmission reception point, downlink control information that is indicative of a set of resources for transmitting the first indication and the second indication, wherein receiving the first indication and the second indication is based at least in part on transmitting the downlink control information.
The method of claim 24, wherein:

the downlink control information triggers the UE to transmit a channel state information report corresponding to one or more reference signals transmitted by one of the first transmission reception point or the second transmission reception point; and

the one or more reference signals include one of the first reference signal or the second reference signal and are associated with unique transmission configuration indicator states of one of the first transmission reception point or the second transmission reception point.
The method of claim 24, wherein:

the downlink control information triggers the UE to transmit a channel state information report corresponding to the first reference signal and the second reference signal;

the first reference signal is associated with a first transmission configuration indicator state; and

the second reference signal is associated with a second transmission configuration indicator state.
The method of claim 21, further comprising:

receiving, from the UE based at least in part on transmitting the first reference signal and the second reference signal, an indication of a transmission reception point, from the first transmission reception point or the second transmission reception point, associated with a reference signal having a higher signal strength.
The method of claim 21, further comprising:

transmitting, to the UE, an indication of a quantity of Doppler shift indications for the UE transmit to the first transmission reception point or the second transmission reception point, wherein receiving the first indication of the first Doppler shift and the second indication of the second Doppler shift is based at least in part on transmitting the indication of the quantity of Doppler shift indications to the UE.
The method of claim 28, further comprising:

transmitting, by a set of transmission reception points comprising at least the first transmission reception point and the second transmission reception point, a set of reference signals to the UE, the set of reference signals comprising at least the first reference signal and the second reference signal; and

receiving the quantity of Doppler shift indications each associated with one of the quantity of reference signals of the set of reference signals having a higher signal strength than remaining reference signals of the set of reference signals.
The method of claim 21, wherein receiving the first indication of the first Doppler shift and the second indication of the second Doppler shift comprises:

receiving, by one of the first transmission reception point or the second transmission reception point, the first indication of the first Doppler shift and the second indication of the second Doppler shift.
The method of claim 21, wherein receiving the first indication of the first Doppler shift and the second indication of the second Doppler shift comprises:

receiving, by the first transmission reception point, the first indication of the first Doppler shift; and

receiving, by the second transmission reception point, the second indication of the second Doppler shift.
The method of claim 21, wherein receiving the first indication of the first Doppler shift and the second indication of the second Doppler shift comprises:

receiving a channel state information report comprising the first indication of the first Doppler shift, the second indication of the second Doppler shift, or both.
The method of claim 21, wherein receiving the first indication of the first Doppler shift and the second indication of the second Doppler shift comprises:

receiving the first indication of the first Doppler shift and the second indication of the second Doppler shift by a physical uplink control channel or a physical uplink shared channel.
The method of claim 21, wherein transmitting the first reference signal and the second reference signal comprises:

transmitting the first reference signal to the UE by a first remote radio head of the first transmission reception point; and

transmitting the second reference signal the UE by a second remote radio head of the second transmission reception point, wherein the first transmission reception point and the second transmission reception point are the same.
The method of claim 21, wherein the first reference signal and the second reference signal are tracking reference signals, channel state information reference signals, synchronization signal block transmissions, or a combination thereof.
The method of claim 21, wherein:

the first reference signal and the second reference signal are channel state information reference signals; and

a set of resources associated with the first reference signal and the second reference signal are configured for a channel measurement procedure.
The method of claim 21, wherein:

transmitting the first reference signal from the first transmission reception point is based at least in part on a first transmission configuration indicator state; and

transmitting the second reference signal from the second transmission reception point is based at least in part on a second transmission configuration indicator state different than the first transmission configuration indicator state.
The method of claim 21, wherein:

the first Doppler shift is associated with a first control resource set index; and

the second Doppler shift is associated with a second control resource set index.
An apparatus for wireless communication at a user equipment (UE) , comprising:

a processor,

memory coupled with the processor; and

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

receive a first reference signal from a first transmission reception point and a second reference signal from a second transmission reception point;

estimate a first Doppler shift associated with the first transmission reception point based at least in part on receiving the first reference signal;

estimate a second Doppler shift associated with the second transmission reception point based at least in part on receiving the second reference signal; and

transmit both of a first indication of the first Doppler shift and a second indication of the second Doppler shift, with at least one of the first indication or the second indication being transmitted to at least one of the first transmission reception point or the second transmission reception point.
An apparatus for wireless communication at a cell associated with a first transmission reception point and a second transmission reception point, comprising:

a processor,

memory coupled with the processor; and

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

transmit, by the first transmission reception point, a first reference signal to a user equipment (UE) ;

transmit, by the second transmission reception point, a second reference signal to the UE;

receive, from the UE, a first indication of a first Doppler shift associated with the first transmission reception point based at least in part on transmitting the first reference signal; and

receive, from the UE, a second indication of a second Doppler shift associated with the second transmission reception point based at least in part on transmitting the second reference signal.
An apparatus for wireless communication at a user equipment (UE) , comprising:

means for receiving a first reference signal from a first transmission reception point and a second reference signal from a second transmission reception point;

means for estimating a first Doppler shift associated with the first transmission reception point based at least in part on receiving the first reference signal;

means for estimating a second Doppler shift associated with the second transmission reception point based at least in part on receiving the second reference signal; and

means for transmitting both of a first indication of the first Doppler shift and a second indication of the second Doppler shift, with at least one of the first indication or the second indication being transmitted to at least one of the first transmission reception point or the second transmission reception point.
An apparatus for wireless communication at a cell associated with a first transmission reception point and a second transmission reception point, comprising:

means for transmitting, by the first transmission reception point, a first reference signal to a user equipment (UE) ;

means for transmitting, by the second transmission reception point, a second reference signal to the UE;

means for receiving, from the UE, a first indication of a first Doppler shift associated with the first transmission reception point based at least in part on transmitting the first reference signal; and

means for receiving, from the UE, a second indication of a second Doppler shift associated with the second transmission reception point based at least in part on transmitting the second reference signal.
A non-transitory computer-readable medium storing code for wireless communication at a user equipment (UE) , the code comprising instructions executable by a processor to:

receive a first reference signal from a first transmission reception point and a second reference signal from a second transmission reception point;

estimate a first Doppler shift associated with the first transmission reception point based at least in part on receiving the first reference signal;

estimate a second Doppler shift associated with the second transmission reception point based at least in part on receiving the second reference signal; and

transmit both of a first indication of the first Doppler shift and a second indication of the second Doppler shift, with at least one of the first indication or the second indication being transmitted to at least one of the first transmission reception point or the second transmission reception point.
A non-transitory computer-readable medium storing code for wireless communication at a cell associated with a first transmission reception point and a second transmission reception point, the code comprising instructions executable by a processor to:

transmit, by the first transmission reception point, a first reference signal to a user equipment (UE) ;

transmit, by the second transmission reception point, a second reference signal to the UE;

receive, from the UE, a first indication of a first Doppler shift associated with the first transmission reception point based at least in part on transmitting the first reference signal; and

receive, from the UE, a second indication of a second Doppler shift associated with the second transmission reception point based at least in part on transmitting the second reference signal.