WO2021147119A1

WO2021147119A1 - Interference-based sounding reference signal beam determination

Info

Publication number: WO2021147119A1
Application number: PCT/CN2020/074050
Authority: WO
Inventors: Min Huang; Chenxi HAO; Qiaoyu Li
Original assignee: Qualcomm Incorporated
Priority date: 2020-01-25
Filing date: 2020-01-25
Publication date: 2021-07-29

Abstract

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive a sounding reference signal (SRS) resource configuration indicating an SRS resource. The UE may determine an SRS transmission beam, for transmission of an SRS in the SRS resource to a target transmit receive point (TRP) based at least in part on one or more SRS transmission beams associated with the target TRP and one or more reference signals transmitted from one or more non-target TRPs. Numerous other aspects are provided.

Description

INTERFERENCE-BASED SOUNDING REFERENCE SIGNAL BEAM DETERMINATION

FIELD OF THE DISCLOSURE

Aspects of the present disclosure generally relate to wireless communication and to techniques and apparatuses for interference-based sounding reference signal (SRS) beam determination.

BACKGROUND

Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. Typical wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, and/or the like) . Examples of such multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency-division multiple access (FDMA) systems, orthogonal frequency-division multiple access (OFDMA) systems, single-carrier frequency-division multiple access (SC-FDMA) systems, time division synchronous code division multiple access (TD-SCDMA) systems, and Long Term Evolution (LTE) . LTE/LTE-Advanced is a set of enhancements to the Universal Mobile Telecommunications System (UMTS) mobile standard promulgated by the Third Generation Partnership Project (3GPP) .

A wireless communication network may include a number of base stations (BSs) that can support communication for a number of user equipment (UEs) . A user equipment (UE) may communicate with a base station (BS) via the downlink and uplink. The downlink (or forward link) refers to the communication link from the BS to the UE, and the uplink (or reverse link) refers to the communication link from the UE to the BS. As will be described in more detail herein, a BS may be referred to as a Node B, a gNB, an access point (AP) , a radio head, a transmit receive point (TRP) , a New Radio (NR) BS, a 5G Node B, and/or the like.

The above multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different user equipment to communicate on a municipal, national, regional, and even global level. New Radio (NR) , which may also be referred to as 5G, is a set of enhancements to the LTE mobile standard promulgated by the Third Generation Partnership Project (3GPP) . NR is designed to better support mobile broadband Internet access by improving spectral efficiency, lowering costs, improving services, making use of new spectrum, and better integrating with other open standards using orthogonal frequency division multiplexing (OFDM) with a cyclic prefix (CP) (CP-OFDM) on the downlink (DL) , using CP-OFDM and/or SC-FDM (e.g., also known as discrete Fourier transform spread OFDM (DFT-s-OFDM) ) on the uplink (UL) , as well as supporting beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation. However, as the demand for mobile broadband access continues to increase, there exists a need for further improvements in LTE and NR technologies. Preferably, these improvements should be applicable to other multiple access technologies and the telecommunication standards that employ these technologies.

SUMMARY

In some aspects, a method of wireless communication, performed by a user equipment (UE) , may include receiving a sounding reference signal (SRS) resource configuration indicating an SRS resource; and determining an SRS transmission beam, for transmission of an SRS in the SRS resource to a target transmit receive point (TRP) based at least in part on one or more SRS transmission beams associated with the target TRP and one or more reference signals transmitted from one or more non-target TRPs.

In some aspects, a UE for wireless communication may include a memory and one or more processors operatively coupled to the memory. The memory and the one or more processors may be configured to receive an SRS resource configuration indicating an SRS resource; and determine an SRS transmission beam, for transmission of an SRS in the SRS resource to a target TRP based at least in part on one or more SRS transmission beams associated with the target TRP and one or more reference signals transmitted from one or more non-target TRPs.

In some aspects, a non-transitory computer-readable medium may store one or more instructions for wireless communication. The one or more instructions, when executed by one or more processors of a UE, may cause the one or more processors to receive an SRS resource configuration indicating an SRS resource; and determine an SRS transmission beam, for transmission of an SRS in the SRS resource to a target TRP based at least in part on one or more SRS transmission beams associated with the target TRP and one or more reference signals transmitted from one or more non-target TRPs.

In some aspects, an apparatus for wireless communication may include means for receiving an SRS resource configuration indicating an SRS resource; and means for determining an SRS transmission beam, for transmission of an SRS in the SRS resource to a target TRP based at least in part on: one or more SRS transmission beams associated with the target TRP and one or more reference signals transmitted from one or more non-target TRPs.

Aspects generally include a method, apparatus, system, computer program product, non-transitory computer-readable medium, user equipment, base station, wireless communication device, and/or processing system as substantially described herein with reference to and as illustrated by the accompanying drawings, specification, and appendix.

The foregoing has outlined rather broadly the features and technical advantages of examples according to the disclosure in order that the detailed description that follows may be better understood. Additional features and advantages will be described hereinafter. The conception and specific examples disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present disclosure. Such equivalent constructions do not depart from the scope of the appended claims. Characteristics of the concepts disclosed herein, both their organization and method of operation, together with associated advantages will be better understood from the following description when considered in connection with the accompanying figures. Each of the figures is provided for the purposes of illustration and description, and not as a definition of the limits of the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

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

Fig. 1 is a block diagram conceptually illustrating an example of a wireless communication network, in accordance with various aspects of the present disclosure.

Fig. 2 is a block diagram conceptually illustrating an example of a base station in communication with a user equipment (UE) in a wireless communication network, in accordance with various aspects of the present disclosure.

Fig. 3 is a diagram illustrating an example of mutual interference, in accordance with various aspects of the present disclosure.

Fig. 4 is a diagram illustrating one or more examples of interference-based sounding reference signal (SRS) beam determination, in accordance with various aspects of the present disclosure.

Fig. 5 is a diagram illustrating an example process performed, for example, by a UE, in accordance with various aspects of the present disclosure.

Fig. 6 is a conceptual data flow diagram illustrating an example of a data flow between different components in an example apparatus.

Fig. 7 is a diagram illustrating an example of a hardware implementation for an apparatus employing a processing system.

DETAILED DESCRIPTION

Various aspects of the disclosure are described more fully hereinafter with reference to the accompanying drawings. This disclosure may, however, be embodied in many different forms and should not be construed as limited to any specific structure or function presented throughout this disclosure. Rather, these aspects are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. Based on the teachings herein one skilled in the art should appreciate that the scope of the disclosure is intended to cover any aspect of the disclosure disclosed herein, whether implemented independently of or combined with any other aspect of the disclosure. For example, an apparatus may be implemented or a method may be practiced using any number of the aspects set forth herein. In addition, the scope of the disclosure is intended to cover such an apparatus or method which is practiced using other structure, functionality, or structure and functionality in addition to or other than the various aspects of the disclosure set forth herein. It should be understood that any aspect of the disclosure disclosed herein may be embodied by one or more elements of a claim.

Several aspects of telecommunication systems will now be presented with reference to various apparatuses and techniques. These apparatuses and techniques will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, modules, components, circuits, steps, processes, algorithms, and/or the like (collectively referred to as “elements” ) . These elements may be implemented using hardware, software, or combinations thereof. Whether such elements are implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system.

It should be noted that while aspects may be described herein using terminology commonly associated with 3G and/or 4G wireless technologies, aspects of the present disclosure can be applied in other generation-based communication systems, such as 5G and later, including NR technologies.

Fig. 1 is a diagram illustrating a wireless network 100 in which aspects of the present disclosure may be practiced. The wireless network 100 may be an LTE network or some other wireless network, such as a 5G or NR network. The wireless network 100 may include a number of BSs 110 (shown as BS 110a, BS 110b, BS 110c, and BS 110d) and other network entities. A BS is an entity that communicates with user equipment (UEs) and may also be referred to as a base station, a NR BS, a Node B, a gNB, a 5G node B (NB) , an access point, a transmit receive point (TRP) , and/or the like. Each BS may provide communication coverage for a particular geographic area. In 3GPP, the term “cell” can refer to a coverage area of a BS and/or a BS subsystem serving this coverage area, depending on the context in which the term is used.

A BS may provide communication coverage for a macro cell, a pico cell, a femto cell, and/or another type of cell. A macro cell may cover a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscription. A pico cell may cover a relatively small geographic area and may allow unrestricted access by UEs with service subscription. A femto cell may cover a relatively small geographic area (e.g., a home) and may allow restricted access by UEs having association with the femto cell (e.g., UEs in a closed subscriber group (CSG) ) . A BS for a macro cell may be referred to as a macro BS. A BS for a pico cell may be referred to as a pico BS. A BS for a femto cell may be referred to as a femto BS or a home BS. In the example shown in Fig. 1, a BS 110a may be a macro BS for a macro cell 102a, a BS 110b may be a pico BS for a pico cell 102b, and a BS 110c may be a femto BS for a femto cell 102c. A BS may support one or multiple (e.g., three) cells. The terms “eNB” , “base station” , “NR BS” , “gNB” , “TRP” , “AP” , “node B” , “5G NB” , and “cell” may be used interchangeably herein.

In some aspects, a cell may not necessarily be stationary, and the geographic area of the cell may move according to the location of a mobile BS. In some aspects, the BSs may be interconnected to one another and/or to one or more other BSs or network nodes (not shown) in the wireless network 100 through various types of backhaul interfaces such as a direct physical connection, a virtual network, and/or the like using any suitable transport network.

Wireless network 100 may also include relay stations. A relay station is an entity that can receive a transmission of data from an upstream station (e.g., a BS or a UE) and send a transmission of the data to a downstream station (e.g., a UE or a BS) . A relay station may also be a UE that can relay transmissions for other UEs. In the example shown in Fig. 1, a relay station 110d may communicate with macro BS 110a and a UE 120d in order to facilitate communication between BS 110a and UE 120d. A relay station may also be referred to as a relay BS, a relay base station, a relay, and/or the like.

Wireless network 100 may be a heterogeneous network that includes BSs of different types, e.g., macro BSs, pico BSs, femto BSs, relay BSs, and/or the like. These different types of BSs may have different transmit power levels, different coverage areas, and different impacts on interference in wireless network 100. For example, macro BSs may have a high transmit power level (e.g., 5 to 40 Watts) whereas pico BSs, femto BSs, and relay BSs may have lower transmit power levels (e.g., 0.1 to 2 Watts) .

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

UEs 120 (e.g., 120a, 120b, 120c) may be dispersed throughout wireless network 100, and each UE may be stationary or mobile. A UE may also be referred to as an access terminal, a terminal, a mobile station, a subscriber unit, a station, and/or the like. A UE may be a cellular phone (e.g., a smart phone) , a personal digital assistant (PDA) , a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a tablet, a camera, a gaming device, a netbook, a smartbook, an ultrabook, a medical device or equipment, biometric sensors/devices, wearable devices (smart watches, smart clothing, smart glasses, smart wrist bands, smart jewelry (e.g., smart ring, smart bracelet) ) , an entertainment device (e.g., a music or video device, or a satellite radio) , a vehicular component or sensor, smart meters/sensors, industrial manufacturing equipment, a global positioning system device, or any other suitable device that is configured to communicate via a wireless or wired medium.

Some UEs may be considered machine-type communication (MTC) or evolved or enhanced machine-type communication (eMTC) UEs. MTC and eMTC UEs include, for example, robots, drones, remote devices, sensors, meters, monitors, location tags, and/or the like, that may communicate with a base station, another device (e.g., remote device) , or some other entity. A wireless node may provide, for example, connectivity for or to a network (e.g., a wide area network such as Internet or a cellular network) via a wired or wireless communication link. Some UEs may be considered Internet-of-Things (IoT) devices, and/or may be implemented as NB-IoT (narrowband internet of things) devices. Some UEs may be considered a Customer Premises Equipment (CPE) . UE 120 may be included inside a housing that houses components of UE 120, such as processor components, memory components, and/or the like.

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

In some aspects, two or more UEs 120 (e.g., shown as UE 120a and UE 120e) may communicate directly using one or more sidelink channels (e.g., without using a base station 110 as an intermediary to communicate with one another) . For example, the UEs 120 may communicate using peer-to-peer (P2P) communications, device-to-device (D2D) communications, a vehicle-to-everything (V2X) protocol (e.g., which may include a vehicle-to-vehicle (V2V) protocol, a vehicle-to-infrastructure (V2I) protocol, and/or the like) , a mesh network, and/or the like. In this case, the UE 120 may perform scheduling operations, resource selection operations, and/or other operations described elsewhere herein as being performed by the base station 110.

As indicated above, Fig. 1 is provided as an example. Other examples may differ from what is described with regard to Fig. 1.

Fig. 2 shows a block diagram of a design 200 of base station 110 and UE 120, which may be one of the base stations and one of the UEs in Fig. 1. Base station 110 may be equipped with T antennas 234a through 234t, and UE 120 may be equipped with R antennas 252a through 252r, where in general T ≥ 1 and R ≥ 1.

At base station 110, a transmit processor 220 may receive data from a data source 212 for one or more UEs, select one or more modulation and coding schemes (MCS) for each UE based at least in part on channel quality indicators (CQIs) received from the UE, process (e.g., encode and modulate) the data for each UE based at least in part on the MCS (s) selected for the UE, and provide data symbols for all UEs. Transmit processor 220 may also process system information (e.g., for semi-static resource partitioning information (SRPI) and/or the like) and control information (e.g., CQI requests, grants, upper layer signaling, and/or the like) and provide overhead symbols and control symbols. Transmit processor 220 may also generate reference symbols for reference signals (e.g., the cell-specific reference signal (CRS) ) and synchronization signals (e.g., the primary synchronization signal (PSS) and secondary synchronization signal (SSS) ) . A transmit (TX) multiple-input multiple-output (MIMO) processor 230 may perform spatial processing (e.g., precoding) on the data symbols, the control symbols, the overhead symbols, and/or the reference symbols, if applicable, and may provide T output symbol streams to T modulators (MODs) 232a through 232t. Each modulator 232 may process a respective output symbol stream (e.g., for OFDM and/or the like) to obtain an output sample stream. Each modulator 232 may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. T downlink signals from modulators 232a through 232t may be transmitted via T antennas 234a through 234t, respectively. According to various aspects described in more detail below, the synchronization signals can be generated with location encoding to convey additional information.

At UE 120, antennas 252a through 252r may receive the downlink signals from base station 110 and/or other base stations and may provide received signals to demodulators (DEMODs) 254a through 254r, respectively. Each demodulator 254 may condition (e.g., filter, amplify, downconvert, and digitize) a received signal to obtain input samples. Each demodulator 254 may further process the input samples (e.g., for OFDM and/or the like) to obtain received symbols. A MIMO detector 256 may obtain received symbols from all R demodulators 254a through 254r, perform MIMO detection on the received symbols if applicable, and provide detected symbols. A receive processor 258 may process (e.g., demodulate and decode) the detected symbols, provide decoded data for UE 120 to a data sink 260, and provide decoded control information and system information to a controller/processor 280. A channel processor may determine reference signal received power (RSRP) , received signal strength indicator (RSSI) , reference signal received quality (RSRQ) , channel quality indicator (CQI) , and/or the like. In some aspects, one or more components of UE 120 may be included in a housing.

On the uplink, at UE 120, a transmit processor 264 may receive and process data from a data source 262 and control information (e.g., for reports comprising RSRP, RSSI, RSRQ, CQI, and/or the like) from controller/processor 280. Transmit processor 264 may also generate reference symbols for one or more reference signals. The symbols from transmit processor 264 may be precoded by a TX MIMO processor 266 if applicable, further processed by modulators 254a through 254r (e.g., for DFT-s-OFDM, CP-OFDM, and/or the like) , and transmitted to base station 110. At base station 110, the uplink signals from UE 120 and other UEs may be received by antennas 234, processed by demodulators 232, detected by a MIMO detector 236 if applicable, and further processed by a receive processor 238 to obtain decoded data and control information sent by UE 120. Receive processor 238 may provide the decoded data to a data sink 239 and the decoded control information to controller/processor 240. Base station 110 may include communication unit 244 and communicate to network controller 130 via communication unit 244. Network controller 130 may include communication unit 294, controller/processor 290, and memory 292.

Controller/processor 240 of base station 110, controller/processor 280 of UE 120, and/or any other component (s) of Fig. 2 may perform one or more techniques associated with interference-based sounding reference signal (SRS) beam determination, as described in more detail elsewhere herein. For example, controller/processor 240 of base station 110, controller/processor 280 of UE 120, and/or any other component (s) of Fig. 2 may perform or direct operations of, for example, process 500 of Fig. 5 and/or other processes as described herein.

Memories

242 and 282 may store data and program codes for base station 110 and UE 120, respectively. In some aspects, memory 242 and/or memory 282 may comprise a non-transitory computer-readable medium storing one or more instructions for wireless communication. For example, the one or more instructions, when executed by one or more processors of the base station 110 and/or the UE 120, may perform or direct operations of, for example, process 500 of Fig. 5 and/or other processes as described herein. A scheduler 246 may schedule UEs for data transmission on the downlink and/or uplink.

In some aspects, UE 120 may include means for receiving an SRS resource configuration indicating an SRS resource, means for determining an SRS transmission beam, for transmission of an SRS in the SRS resource to a target TRP based at least in part on one or more SRS transmission beams associated with the target TRP and one or more reference signals transmitted from one or more non-target TRPs, and/or the like. In some aspects, such means may include one or more components of UE 120 described in connection with Fig. 2, such as controller/processor 280, transmit processor 264, TX MIMO processor 266, MOD 254, antenna 252, DEMOD 254, MIMO detector 256, receive processor 258, and/or the like.

As indicated above, Fig. 2 is provided as an example. Other examples may differ from what is described with regard to Fig. 2.

Fig. 3 is a diagram illustrating an example 300 of mutual interference. As shown in Fig. 3, example 300 may include a plurality of TRPs. The TRPs may be TRPs of the same BS or may be TRPs of different BSs. As further shown in Fig. 3, example 300 may include a plurality of UEs. In some cases, each UE (e.g., UE1, UE2, and so on) may be capable of communicating with one of the TRPs. In some cases, a UE may be capable of communicating with two or more of the TRPs, which may be referred to as a multi-TRP configuration. In this case, the BS communicatively connects with two or more of the TRPs (which may be geographically distributed) , and the BS may separately or jointly transmit communications to one or more of the UEs and/or may separately or jointly receive signals from one or more of the UEs via the two or more TRPs. This increases transmit diversity, increases system capacity, and/or increases cell coverage for the BS and the UEs.

In some cases, the BS may schedule a UE to transmit an uplink communication to a TRP via an uplink scheduling grant, such as a format 0_1 downlink control information (DCI) communication. The uplink scheduling grant may indicate an uplink beam on which the UE is to transmit the uplink communication, may indicate a time-frequency resource in which to transmit the uplink communication, and/or the like. The BS may determine one or more parameters for the uplink beam (e.g., beam direction, beam weight, and/or the like) , and one or more parameters for the transmission of the uplink communication (e.g., resource assignment, transport format, modulation coding scheme, quantity of layers, and/or the like) , based at least in part on one or more SRSs transmitted by the UE. The BS may determine the one or more parameters for the uplink beam based at least in part on channel gains of the one or more SRSs (e.g., by selecting the parameters based at least in part on the SRS transmission beams for the SRS with the highest channel gains) .

In some cases, the BS may configure SRS resources for transmission of the one or more SRSs in radio resource control (RRC) signaling. The RRC signaling may include an SRS resource configuration, which may include SRS spatial relation information (SRS-SpatialRelationInfo) . In some cases, if the SRS resource configuration identifies an SRS resource, the UE may transmit an SRS on the SRS transmission beam associated with the SRS resource. If the SRS resource configuration identifies a reference signal index (e.g., a synchronization signal block (SSB) index, a channel state information reference signal (CSI-RS) index, a demodulation reference signal (DMRS) index, and/or the like) for an SRS resource, the UE may use the SRS transmission beam, that is used to receive the reference signal to which the reference signal index is assigned, to transmit the SRS.

In some cases, a BS may configure UE1 to transmit an uplink communication to a target TRP (e.g., a TRP that is the intended or target recipient of the uplink communications) on a target uplink during the same time-frequency resource in which UE2 is scheduled to transmit another uplink communication to a non-target TRP (e.g., a TRP that is not the target TRP of UE1) on a non-target uplink. While this may increase spectrum efficiency and throughput, if UE1 and UE2 separately transmit uplink communications in the same time-frequency resource to different TRPs without uplink beam coordination, the uplink communications may cause mutual interference at the TRPs.

Mutual interference may refer to the interference with the uplink communication transmitted by UE2 to the non-target TRP caused by transmission of the uplink communication from UE1 to the target TRP, and the interference with the uplink communication transmitted by UE1 to the target TRP caused by transmission of the uplink communication from UE2 to the non-target TRP. Mutual interference may be represented as an interference link, which may be an access link between a UE and a non-target TRP that causes interference on a target uplink between another UE and the non-target TRP (which is the target TRP for the UE) . Mutual interference may result in poor or reduced reception performance for the TRPs, which in turn can cause decoding errors, dropped uplink communications, an increase in uplink retransmissions, and/or the like.

As indicated above, Fig. 3 is provided as an example. Other examples may differ from what is described with regard to Fig. 3.

In some cases, determining an uplink beam (e.g., an SRS transmission beam) for an uplink communication based at least in part on an SRS resource configuration may result in an increase in mutual interference if the SRS resource configuration only considers the channel gain on a target link to a target TRP of a UE. By only considering the target link to the target TRP, the UE can transmit an uplink communication on an SRS transmission beam that can enhance the channel gain of the target link. However, the transmission of the uplink communication using an SRS transmission beam that is determined without consideration of the interference caused to uplink communication reception at non-target TRPs may cause an increase in mutual interference with the non-target uplinks of the non-target TRPs, which may lead to weak reception performance (e.g., low signal to interference plus noise ratio (SINR) ) of uplink communications received by the non-target TRPs during the same time-frequency resource in which the uplink communication is transmitted by the UE.

Some aspects described herein provide techniques and apparatuses for interference-based SRS beam determination. In some aspects, a BS may configure an SRS resource configuration that indicates an SRS resource for transmitting an SRS to a target TRP. A UE may receive the SRS resource configuration and may determine an SRS transmission beam for transmitting the SRS in the SRS resource. The UE may be configured to determine the SRS transmission beam based at least in part on one or more SRS transmission beams associated with the target TRP and one or more reference signals transmitted from one or more non-target TRPs. In this way, the UE considers the channel gain on the target uplink to the target TRP as well as estimated or measured interference (e.g., mutual interference) that transmission on the target uplink may cause to the non-target TRPs (e.g., based at least in part on the one or more reference signals) , which reduces mutual interference for the non-target TRPs while increasing channel gain on the target uplink. Moreover, the UE may determine the current SRS transmission beam by reusing the previous SRS transmission beams associated with the target TRP to the extent possible, which conserves energy and processing resources of the UE and reduces latency relative to remeasuring or re-sweeping the reference signal (s) of the target TRP to regenerate the SRS transmission beams of the target TRP.

Fig. 4 is a diagram illustrating one or more examples 400 of interference-based SRS beam determination, in accordance with various aspects of the present disclosure. As shown in Fig. 4, example (s) 400 may include communication between a UE (e.g., UE 120) and a BS (e.g., BS 110) . In some aspects, the BS may be communicatively connected with a plurality of TRPs in a multi-TRP configuration. In some aspects, the UE and the BS may be included in a wireless network, such as wireless network 100. In some aspects, the TRPs may include a target TRP and one or more non-target TRPs. The target TRP may be a TRP to which the UE is to transmit one or more uplink communications on a target uplink. The non-target TRP (s) may be TRP (s) that are different from the target TRP, and for which the UE is not scheduled or configured to transmit uplink communications.

In some aspects, the BS may transmit an uplink scheduling grant to the UE to configure the UE to transmit an uplink communication (e.g., an uplink data communication on a physical uplink shared channel (PUSCH) , an uplink control communication on a physical uplink control channel (PUCCH) , and/or the like) to the target TRP. The uplink scheduling grant may identify an uplink beam on which to transmit the uplink communication, may identify a time-frequency resource in which to transmit the uplink communication, and/or the like.

As shown in Fig. 4, and by reference number 402, to select an uplink beam for an uplink scheduling grant, the BS may transmit an SRS resource configuration to the UE. The SRS resource configuration may indicate an SRS resource in which to transmit an SRS to the target TRP on the target uplink. The SRS resource may include an uplink time-frequency resource, which may include one or more slots, one or more symbols, one or more resource blocks, one or more resource elements, and/or the like.

In some aspects, the BS may transmit the SRS resource configuration to the UE via a target downlink of the target TRP. In some aspects, the BS may transmit the SRS resource configuration to the UE in one or more RRC communications, in one or more DCI communications, in one or more medium access control control element (MAC-CE) communications, and/or other types of downlink communications.

As further shown in Fig. 4, and by reference number 404, the UE may determine an SRS transmission beam for transmitting the SRS in the SRS resource. In some aspects, the UE may determine the SRS transmission beam based at least in part on one or more SRS transmission beams associated with the target TRP and one or more reference signals transmitted by the one or more non-target TRPs. In some aspects, the one or more SRS beams associated with the target TRP and/or the one or more reference signals transmitted by the one or more non-target TRPs may be indicated in the SRS resource configuration. The one or more SRS beams associated with the target TRP and/or the one or more reference signals transmitted by the one or more non-target TRPs may be indicated in another downlink communication, may be indicated in system information (e.g., a system information block (SIB) , a master information block (MIB) , a remaining minimum system information (RMSI) communication, other system information (OSI) communication, and/or the like) , and/or the like.

In some aspects, the one or more SRS transmission beams associated with the target TRP may be existing or previously determined SRS transmission beams for one or more other SRS resources configured for the target TRP. Each of the other SRS resource (s) may be associated with one or more SRS ports (e.g., antenna ports) . Accordingly, each of the one or more SRS ports may be associated with and/or may represent a respective SRS transmission beam of the one or more SRS transmission beams. In some aspects, the UE may determine or generate the one or more SRS transmission beams associated with the target TRP based at least in part on determining respective sets of beamforming weights for each of the one or more SRS transmission beams and generating an SRS beam of the one or more SRS transmission beams associated with the target TRP based at least in part on a set of beamforming weights for the SRS transmission beam and an SRS port, of the one or more SRS ports, associated with the SRS transmission beam.

In some aspects, the one or more reference signals may be SSBs transmitted by the one or more non-target TRPs, CSI-RSs transmitted by the one or more non-target TRPs, one or more DMRSs transmitted by the one or more non-target TRPs, and/or other types of measurement resources transmitted by the one or more non-target TRPs. In some aspects, the one or more non-target TRPs may transmit the reference signals after the BS transmits the SRS resource configuration and/or concurrently with transmission of the SRS resource configuration. In some aspects, the UE may determine the SRS transmission beam for the SRS by determining respective channel response matrixes for each of the one or more reference signals. The channel response matrix for a reference signal may represent the channel gain of the interference link associated with the non-target TRP that transmitted the reference signal. In this case, the channel gain of the interference link corresponds to the mutual interference between the UE and the non-target TRP.

In some aspects, the UE may determine the SRS transmission beam based at least in part on one or more SRS transmission beam parameters, in addition to the one or more SRS transmission beams associated with the target TRP and the one or more reference signals transmitted by the non-target TRPs. The SRS transmission beam parameters may specify rules, criteria, and/or parameters that dictate how the UE determines the SRS transmission beam based at least in part on the one or more SRS transmission beams associated with the target TRP and the one or more reference signals transmitted by the non-target TRPs.

In some aspects, the UE may receive an indication of the one or more SRS transmission beam parameters in the SRS resource configuration. In some aspects, the UE may receive an indication of the one or more SRS transmission beam parameters in another downlink communication or system information. In some aspects, the one or more SRS transmission beam parameters may be hard-coded, programmed, or configured at the UE in a memory (e.g., memory 282) , in a table, in a specification, and/or the like based at least in part on a standard.

In some aspects, the one or more SRS transmission beam parameters may indicate that the UE is to determine the SRS transmission beam in a manner that maximizes reusage of the one or more SRS transmission beam associated with the target TRP, and reduces or eliminates the interference strengths of the interference links between the UE and the one or more non-target TRPs. For example, the one or more SRS transmission beam parameters may include a first parameter indicating that the UE is to select the SRS transmission beam from the one or more SRS transmission beams associated with the target TRP.

Alternatively, the first parameter may indicate that, if the UE determines the SRS transmission beam to be an SRS transmission beam that is different from the one or more SRS transmission beams associated with the target TRP, then the beam correlation between the determined SRS transmission beam and at least one of the one or more SRS transmission beams associated with the target TRP is to satisfy a beam correlation threshold (e.g., 80%correlation, 90%correlation, and/or the like) . Thus, if an SRS transmission of the one or more SRS transmission beams associated with the target TRP is denoted as a column vector v, and the SRS transmission beam determined by the UE is denoted as a column vector u, the UE may determine the SRS transmission beam such that the value of |u ^Hv| (where u ^H is the Hermitian of the column vector u) is maximized and/or satisfies a threshold value corresponding to the beam correlation threshold. In this way, the first parameter ensures that the determined SRS transmission beam and at least one of the one or more SRS transmission beams associated with the target TRP have a large beam correlation. As an example, the beam correlation threshold is 100%correlation, which means the determined SRS transmission beam is selected from the one or more SRS transmission beams associated with the target TRP.

As another example, the one or more SRS transmission parameters may include a second parameter indicating that the UE is to determine the SRS transmission beam such that the SRS transmission beam is to generate zero interference strength on the access links (e.g., non-target uplinks) associated with the one or more non-target TRPs. In some aspects, zero interference strength to an access link may refer to projection powers of the transmission beam weight vectors on the signal-subspace of the channel response matrixes of non-target TRPs being equal to zero.

In some aspects, the UE may determine the SRS transmission beam such that the SRS transmission beam results in zero interference strength to an access link of a non-target TRP in a 5G NR frequency range 1 (FR1) deployment, where the UE communicates with the target TRP using a sub-6 GHz frequency. In some aspects, the UE may perform a received signal strength measurement of the reference signal transmitted by the non-target TRP (which may indicate the beamformed downlink channel gain on the non-target downlink of the access link) , and may determine the uplink channel response matrix for access link based at least in part on channel reciprocity between the non-target downlink and the non-target uplink of the access link. The uplink channel response matrix may be denoted as H ₁₂. The UE may determine an orthogonal projection matrix of the uplink channel response matrix H ₁₂. The orthogonal projection matrix may be denoted as P ₁₂. The UE may determine the orthogonal projection matrix P ₁₂ such that, for any matrix A having a quantity of rows equal to the number of columns as H ₁₂, the matrix of P ₁₂A is orthogonal to H ₁₂. The UE may determine a projection of a beamforming weight vector, of an SRS transmission beam (denoted as column vector v) of the one or more SRS transmission beams associated with the target TRP, onto the orthogonal projection matrix P ₁₂. The UE may determine the projection of the beamforming weight vector that results in column vector u, such that column vector u=P ₁₂v.

Alternatively, the second parameter may indicate that the UE is to determine the SRS transmission beam such that the interference strength of the SRS transmission beam for the access links (e.g., non-target uplinks) associated with the one or more non-target TRPs satisfies an interference strength threshold (e.g. -90 dBm, or 10 dB smaller than the channel gain of the access links associated with the one or more non-target TRPs) . Thus, based at least in part on the second parameter, the UE may determine the SRS transmission beam such that the SRS transmission beam has a sufficiently small projection power on the signal-subspace of the channel response matrixes of non-target TRPs and/or or has a sufficiently large projection power on the null-subspace of the channel response matrixes of non-target TRPs.

In some aspects, the UE may determine the interference strength on an access link associated with a non-target TRP by determining a beamformed downlink channel gain on a non-target downlink associated with the non-target TRP. The UE may determine the interference strength of the SRS transmission beam based at least in part on reciprocity between the interference strength of the SRS transmission beam and the beamformed downlink channel gain on the non-target downlink associated with the non-target TRP. The UE may determine whether the interference strength of the SRS transmission satisfies the interference strength threshold indicated in the one or more SRS transmission beam parameters.

In some aspects, the UE may determine the beamformed downlink channel gain on the access links associated with the non-target TRP by identifying a transmission power for the reference signal (s) transmitted by the non-target TRP and determining the beamformed downlink channel gain based at least in part on the transmission power of the reference signal (s) . In some aspects, the UE may identify the transmission power for the reference signal (s) based at least in part on an indication of the transmission power in the SRS resource configuration, based at least in part on an indication of the transmission power in another downlink communication or system information received from the BS, based at least in part on the transmission power being indicated in a specification or standard and programmed or configured for the UE, and/or the like.

In some aspects, the UE may determine the SRS transmission beam in a 5G NR frequency range 2 (FR2) configuration (e.g., where the UE communicates with the target TRP using a millimeter wave (mmWave) frequency) . In this case, the UE may determine correlation coefficients between one or more reference SRS transmission beams and the one or more SRS transmission beams associated with the target TRP. The UE may determine one or more downlink beams based on the one or more reference SRS transmission beams. The UE may beam sweep the one or more downlink beams to receive the one or more reference signals transmitted from the one or more non-target TRPs. The UE may determine respective beamformed downlink channel gains for each of the one or more downlink beams based at least in part on the one or more reference signals. The UE may determine respective uplink interference strengths for the one or more reference SRS transmission beams based at least in part on the respective beamformed downlink channel gains and reciprocity between the one or more reference SRS transmission beams and the one or more downlink beams. The UE may determine the SRS transmission beam based at least in part on the respective uplink interference strengths and the respective correlation coefficients for the one or more reference SRS transmission beams.

As further shown in Fig. 4, and by reference number 406, the UE may transmit the SRS in the SRS resource indicated in the SRS resource configuration. Moreover, the UE may transmit the SRS using the SRS transmission beam determined by the UE (e.g., based at least in part on the one or more SRS transmission beams associated with the target TRP, the one or more reference signals transmitted by the one or more non-target TRPs, and/or the one or more SRS transmission beam parameters) . The target TRP may relay, forward, and/or provide information associated with the SRS to the BS, such as the SRS transmission beam on which the SRS was transmitted.

As further shown in Fig. 4, and by reference number 408, the BS may configure an uplink scheduling grant for transmission of an uplink data communication. In some aspects, the BS may configure the uplink scheduling grant based at least in part on the SRS, the SRS transmission beam on which the SRS was transmitted, and/or the like. The uplink scheduling grant may identify a time-frequency resource in which to transmit the uplink data communication, may identify an uplink beam on which to transmit the uplink data communication, and/or the like. In some aspects, the uplink beam may be the SRS transmission beam on which the UE transmitted the SRS to the target TRP.

As further shown in Fig. 4, and by reference number 410, the BS may transmit the uplink scheduling grant to the UE. In some aspects, the BS may transmit the uplink scheduling grant via the target TRP. In this case, the UE may receive the uplink scheduling grant from the target TRP via the target downlink associated with the target TRP.

As further shown in Fig. 4, and by reference number 412, the UE may transmit the uplink data communication to the target TRP based at least in part on the uplink scheduling grant. For example, the UE may transmit the uplink data communication in the time-frequency resource indicated in the uplink scheduling grant, may transmit the uplink data communication using the uplink beam (e.g., the SRS transmission beam) indicated in the uplink scheduling grant, and/or the like.

In this way, the UE may be configured to determine the SRS transmission beam based at least in part on one or more SRS transmission beams associated with the target TRP and one or more reference signals transmitted from one or more non-target TRPs. Accordingly, the UE considers the channel gain on the target uplink to the target TRP as well as estimated or measured interference (e.g., mutual interference) that transmission on the target uplink may cause to the non-target TRPs (e.g., based at least in part on the one or more reference signals) , which reduces mutual interference for the non-target TRPs while increasing channel gain on the target uplink. Moreover, the UE may determine the current SRS transmission beam by reusing the previous SRS transmission beams associated with the target TRP to the extent possible, which conserves energy and processing resources of the UE and reduces latency relative to remeasuring or re-sweeping the reference signal (s) of the target TRP to regenerate the SRS transmission beams of the target TRP.

As indicated above, Fig. 4 is provided as one or more examples. Other examples may differ from what is described with respect to Fig. 4.

Fig. 5 is a diagram illustrating an example process 500 performed, for example, by a UE, in accordance with various aspects of the present disclosure. Example process 500 is an example where the UE (e.g., UE 120 depicted and described in connection with Figs. 1 and/or 2, UE1 or UE2 depicted and described in connection with Fig. 3, the UE depicted and described in connection with Fig. 4, the apparatus 602 depicted and described in connection with Fig. 6, the apparatus 602′ depicted and described in connection with Fig. 7, and/or the like) performs operations associated with interference-based SRS beam determination.

As shown in Fig. 5, in some aspects, process 500 may include receiving an SRS resource configuration indicating an SRS resource (block 510) . For example, the UE (e.g., using receive processor 258, transmit processor 264, controller/processor 280, memory 282, and/or the like) may receive an SRS resource configuration indicating an SRS resource, as described above in connection with Fig. 4.

In some aspects, receiving the SRS resource configuration comprises receiving the SRS resource configuration in one or more RRC communications, one or more MAC-CE communications, or one or more DCI communications.

As further shown in Fig. 5, in some aspects, process 500 may include determining an SRS transmission beam, for transmission of an SRS in the SRS resource to a target TRP, based at least in part on one or more SRS transmission beams associated with the target TRP and one or more reference signals transmitted from one or more non-target TRPs (block 520) . For example, the UE (e.g., using receive processor 258, transmit processor 264, controller/processor 280, memory 282, and/or the like) may determine an SRS transmission beam, for transmission of an SRS in the SRS resource to a target TRP, based at least in part on one or more SRS transmission beams associated with the target TRP and one or more reference signals transmitted from one or more non-target TRPs, as described above in connection with Fig. 4.

In some aspects, the one or more SRS transmission beams are associated with another, previously configured, SRS resource for the target TRP. In some aspects, the one or more SRS transmission beams are identified in the SRS resource configuration. In some aspects, the one or more reference signals are identified in the SRS resource configuration. In some aspects, the one or more reference signals comprise at least one of a CSI-RS, a DMRS, or an SSB.

In some aspects, determining the SRS transmission beam comprises determining the SRS transmission beam based at least in part on one or more SRS transmission beam parameters. In some aspects, the one or more SRS transmission beam parameters are indicated in the SRS resource configuration. In some aspects, the one or more SRS transmission beam parameters are programmed or configured at the UE and are based at least in part on a standard.

In some aspects, the one or more SRS transmission beam parameters comprise a first parameter indicating that a beam correlation between the SRS transmission beam and a reference SRS transmission beam of the one or more SRS transmission beams is to satisfy a beam correlation threshold, and a second parameter indicating that the SRS transmission beam is to generate zero interference strength on access links associated with the one or more non-target TRPs. In some aspects, the one or more SRS transmission beam parameters comprise a first parameter indicating that a beam correlation between the SRS transmission beam and a reference SRS transmission beam of the one or more SRS transmission beams is to satisfy a beam correlation threshold, and a second parameter indicating an interference strength of the SRS transmission beam for access links associated with the one or more non-target TRPs that satisfies an interference strength threshold.

In some aspects, determining the SRS transmission beam comprises determining, for a non-target TRP of the one or more non-target TRPs, an uplink channel response matrix based at least in part on a reference signal, of the one or more reference signals, transmitted from the non-target TRP; determining an orthogonal projection matrix of the uplink channel response matrix; determining a projection of a beamforming weight vector of a reference SRS transmission beam, of the one or more SRS transmission beams, associated with the target TRP onto the orthogonal projection matrix; and determining a column vector as the beamforming weight vector of the SRS transmission beam, based at least in part on the projection of the vector of the reference SRS transmission beam onto the orthogonal projection matrix.

In some aspects, determining the SRS transmission beam comprises determining respective correlation coefficients between one or more reference SRS transmission beams and the one or more SRS transmission beams; determining one or more downlink beams based on the one or more reference SRS transmission beams; sweeping the one or more downlink beams to receive the one or more reference signals; determining respective beamformed downlink channel gains for each of the one or more downlink beams based at least in part on the one or more reference signals; determining respective uplink interference strengths for the one or more reference SRS transmission beams based at least in part on the respective beamformed downlink channel gains and reciprocity between the one or more reference SRS transmission beams and the one or more downlink beams; and determining the SRS transmission beam based at least in part on the respective uplink interference strengths and the respective correlation coefficients.

Process 500 may include additional aspects, such as any single aspect or any combination of aspects described below and/or in connection with one or more other processes described elsewhere herein.

In some aspects, process 500 includes transmitting, to the target TRP, the SRS in the SRS resource using the SRS transmission beam; receiving an uplink scheduling grant based at least in part on the SRS; and transmitting, based at least in part on the uplink scheduling grant, an uplink data communication using the SRS transmission beam. In some aspects, process 500 includes determining respective sets of beamforming weights for each of the one or more SRS transmission beams; and generating a reference SRS transmission beam of the one or more SRS transmission beams based at least in part on: a set of beamforming weights for the reference SRS transmission beam, and an SRS port, of the one or more SRS ports, associated with the reference SRS transmission beam.

In some aspects, process 500 includes determining respective channel response matrixes for each of the one or more reference signals based at least in part on the SRS resource configuration, and determining the SRS transmission beam comprises determining the SRS transmission beam based at least in part on the respective channel response matrixes. In some aspects, process 500 includes determining a beamformed downlink channel gain on non-target downlinks associated with the one or more non-target TRPs; determining the interference strength of the SRS transmission beam based at least in part on reciprocity between the interference strength of the SRS transmission beam and the beamformed downlink channel gain on the non-target downlinks associated with the one or more non-target TRPs; and determining whether the interference strength of the SRS transmission satisfies the interference strength threshold.

In some aspects, determining the beamformed downlink channel gain on the access links associated with the one or more non-target TRPs comprises identifying respective transmission powers for each of the one or more reference signals, and determining the beamformed downlink channel gain on the non-target downlinks associated with the one or more non-target TRPs based at least in part on the respective transmission powers for each of the one or more reference signals.

In some aspects, identifying the respective transmission powers comprises identifying the respective transmission powers based at least in part on an indication of the respective transmission powers in the SRS resource configuration. In some aspects, identifying the respective transmission powers comprises identifying the respective transmission powers based at least in part on the respective transmission powers being programmed or configured at the UE.

Although Fig. 5 shows example blocks of process 500, in some aspects, process 500 may include additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted in Fig. 5. Additionally, or alternatively, two or more of the blocks of process 500 may be performed in parallel.

Fig. 6 is a conceptual data flow diagram 600 illustrating a data flow between different components in an example apparatus 602. The apparatus 602 may be a UE (e.g., UE 120) . In some aspects, the apparatus 602 includes a reception component 604, a determining component 606, and/or a transmission component 608.

In some aspects, reception component 604 may receive an SRS resource configuration 610 from a BS 620 (e.g., BS 110) . The SRS resource configuration may indicate an SRS resource for transmitting an SRS 614. In some aspects, the determining component 606 may determine an SRS transmission beam for transmission of the SRS 614 in the SRS resource to a target TRP of the BS 620. In some aspects, the determining component may determine the SRS transmission beam based at least in part on one or more SRS transmission beams associated with the target TRP and one or more reference signals 612 transmitted from one or more non-target TRPs of the BS 620. In some aspects, the transmission component 608 may transmit, to the target TRP of the BS 620, the SRS 614 in the SRS resource using the SRS transmission beam.

In some aspects, the reception component 604 may receive an uplink scheduling grant 616 based at least in part on the SRS 614. In some aspects, the transmission component 608 may transmit, based at least in part on the uplink scheduling grant 616, an uplink data communication 618 using the SRS transmission beam.

In some aspects, the reception component 604 may include an antenna (e.g., antenna 252) , a MIMO detector (e.g., MIMO detector 256) , a receive processor (e.g., receive processor 258) , a controller/processor (e.g., controller/processor 280) , a memory (e.g., memory 282) , and/or the like. In some aspects, determining component 606 may include a receive processor (e.g., receive processor 258) , a transmit processor (e.g., transmit processor 264) , a controller/processor (e.g., controller/processor 280) , a memory (e.g., memory 282) , and/or the like. In some aspects, the transmission component 608 may include an antenna (e.g., antenna 252) , a TX MIMO processor (e.g., TX MIMO processor 266) , a transmit processor (e.g., transmit processor 264) , a controller/processor (e.g., controller/processor 280) , a memory (e.g., a memory 282) , and/or the like.

The apparatus may include additional components that perform each of the blocks of the algorithm in the aforementioned process 500 of Fig. 5 and/or the like. Each block in the aforementioned process 500 of Fig. 5 and/or the like may be performed by a component and the apparatus may include one or more of those components. The components may be one or more hardware components specifically configured to carry out the stated processes/algorithm, implemented by a processor configured to perform the stated processes/algorithm, stored within a computer-readable medium for implementation by a processor, or some combination thereof.

The number and arrangement of components shown in Fig. 6 are provided as an example. In practice, there may be additional components, fewer components, different components, or differently arranged components than those shown in Fig. 6. Furthermore, two or more components shown in Fig. 6 may be implemented within a single component, or a single component shown in Fig. 6 may be implemented as multiple, distributed components. Additionally, or alternatively, a set of components (e.g., one or more components) shown in Fig. 6 may perform one or more functions described as being performed by another set of components shown in Fig. 6.

Fig. 7 is a diagram 700 illustrating an example of a hardware implementation for an apparatus 602′ employing a processing system 702. The apparatus 602′ may be a UE (e.g., UE 120) .

The processing system 702 may be implemented with a bus architecture, represented generally by the bus 704. The bus 704 may include any number of interconnecting buses and bridges depending on the specific application of the processing system 702 and the overall design constraints. The bus 704 links together various circuits including one or more processors and/or hardware components, represented by the processor 706, the

components

604, 606, 608, and the computer-readable medium /memory 708. The bus 704 may also link various other circuits such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art, and therefore will not be described any further.

The processing system 702 may be coupled to a transceiver 710. The transceiver 710 is coupled to one or more antennas 712. The transceiver 710 provides a means for communicating with various other apparatuses over a transmission medium. The transceiver 710 receives a signal from the one or more antennas 712, extracts information from the received signal, and provides the extracted information to the processing system 702, specifically the reception component 604. In addition, the transceiver 710 receives information from the processing system 702, specifically the transmission component 608, and based at least in part on the received information, generates a signal to be applied to the one or more antennas 712. The processing system 702 includes a processor 706 coupled to a computer-readable medium /memory 708. The processor 706 is responsible for general processing, including the execution of software stored on the computer-readable medium /memory 708. The software, when executed by the processor 706, causes the processing system 702 to perform the various functions described herein for any particular apparatus. The computer-readable medium /memory 708 may also be used for storing data that is manipulated by the processor 706 when executing software. The processing system further includes at least one of the

components

604, 606, and/or 608. The components may be software modules running in the processor 706, resident/stored in the computer readable medium /memory 708, one or more hardware modules coupled to the processor 706, or some combination thereof. The processing system 702 may be a component of the UE 120 and may include the memory 282 and/or at least one of the TX MIMO processor 266, the RX processor 258, the receive processor 258, the transmit processor 264, and/or the controller/processor 280.

In some aspects, the apparatus 602/602′ for wireless communication includes means for receiving an SRS resource configuration indicating an SRS resource, means for determining an SRS transmission beam, for transmission of an SRS in the SRS resource to a target TRP based at least in part on one or more SRS transmission beams associated with the target TRP and one or more reference signals transmitted from one or more non-target TRPs. In some aspects, the apparatus 602/602′ for wireless communication includes means for transmitting, to the target TRP, the SRS in the SRS resource using the SRS transmission beam, means for receiving an uplink scheduling grant based at least in part on the SRS, means for transmitting, based at least in part on the uplink scheduling grant, an uplink data communication using the SRS transmission beam, and/or the like. The aforementioned means may be one or more of the aforementioned components of the apparatus 602 and/or the processing system 702 of the apparatus 602′ configured to perform the functions recited by the aforementioned means. As described elsewhere herein, the processing system 702 may include the TX MIMO processor 266, the transmit processor 264, the receive processor 258, the MIMO detector 256, and/or the controller/processor 280.

Fig. 7 is provided as an example. Other examples may differ from what is described in connection with Fig. 7.

The foregoing disclosure provides illustration and description, but is not intended to be exhaustive or to limit the aspects to the precise form disclosed. Modifications and variations may be made in light of the above disclosure or may be acquired from practice of the aspects.

As used herein, the term “component” is intended to be broadly construed as hardware, firmware, and/or a combination of hardware and software. As used herein, a processor is implemented in hardware, firmware, and/or a combination of hardware and software.

As used herein, satisfying a threshold may, depending on the context, refer to a value being greater than the threshold, greater than or equal to the threshold, less than the threshold, less than or equal to the threshold, equal to the threshold, not equal to the threshold, and/or the like.

It will be apparent that systems and/or methods described herein may be implemented in different forms of hardware, firmware, and/or a combination of hardware and software. The actual specialized control hardware or software code used to implement these systems and/or methods is not limiting of the aspects. Thus, the operation and behavior of the systems and/or methods were described herein without reference to specific software code-it being understood that software and hardware can be designed to implement the systems and/or methods based, at least in part, on the description herein.

Even though particular combinations of features are recited in the claims and/or disclosed in the specification, these combinations are not intended to limit the disclosure of various aspects. In fact, many of these features may be combined in ways not specifically recited in the claims and/or disclosed in the specification. Although each dependent claim listed below may directly depend on only one claim, the disclosure of various aspects includes each dependent claim in combination with every other claim in the claim set. A phrase referring to “at least one of” a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover a, b, c, a-b, a-c, b-c, and a-b-c, as well as any combination with multiples of the same element (e.g., a-a, a-a-a, a-a-b, a-a-c, a-b-b, a-c-c, b-b, b-b-b, b-b-c, c-c, and c-c-c or any other ordering of a, b, and c) .

No element, act, or instruction used herein should be construed as critical or essential unless explicitly described as such. Also, as used herein, the articles “a” and “an” are intended to include one or more items, and may be used interchangeably with “one or more. ” Furthermore, as used herein, the terms “set” and “group” are intended to include one or more items (e.g., related items, unrelated items, a combination of related and unrelated items, and/or the like) , and may be used interchangeably with “one or more. ” Where only one item is intended, the phrase “only one” or similar language is used. Also, as used herein, the terms “has, ” “have, ” “having, ” and/or the like are intended to be open-ended terms. Further, the phrase “based on” is intended to mean “based, at least in part, on” unless explicitly stated otherwise.

Claims

A method of wireless communication performed by a user equipment (UE) , comprising:

receiving a sounding reference signal (SRS) resource configuration indicating an SRS resource; and

determining an SRS transmission beam, for transmission of an SRS in the SRS resource to a target transmit receive point (TRP) based at least in part on:

one or more SRS transmission beams associated with the target TRP, and

one or more reference signals transmitted from one or more non-target TRPs.
The method of claim 1, further comprising:

transmitting, to the target TRP, the SRS in the SRS resource using the SRS transmission beam;

receiving an uplink scheduling grant based at least in part on the SRS; and

transmitting, based at least in part on the uplink scheduling grant, an uplink data communication using the SRS transmission beam.
The method of claim 1, wherein the one or more SRS transmission beams are associated with another, previously configured, SRS resource for the target TRP;

wherein the other SRS resource is associated with one or more SRS ports; and

wherein each of the one or more SRS ports is associated with a respective SRS transmission beam of the one or more SRS transmission beams.
The method of claim 1, wherein the one or more SRS transmission beams are identified in the SRS resource configuration.
The method of claim 1, further comprising:

determining respective sets of beamforming weights for each of the one or more SRS transmission beams; and

generating a reference SRS transmission beam of the one or more SRS transmission beams based at least in part on:

a set of beamforming weights for the reference SRS transmission beam, and

an SRS port, of the one or more SRS ports, associated with the reference SRS transmission beam.
The method of claim 1, wherein the one or more reference signals are identified in the SRS resource configuration.
The method of claim 1, further comprising:

determining respective channel response matrixes for each of the one or more reference signals based at least in part on the SRS resource configuration; and

wherein determining the SRS transmission beam comprises:

determining the SRS transmission beam based at least in part on the respective channel response matrixes.
The method of claim 7, wherein the one or more reference signals comprise at least one of:

a channel state information reference signal,

a demodulation reference signal, or

a synchronization signal block.
The method of claim 1, wherein receiving the SRS resource configuration comprises:

receiving the SRS resource configuration in at least one of:

one or more radio resource control communications,

one or more medium access control control element communications, or

one or more downlink control information communications.
The method of claim 1, wherein determining the SRS transmission beam comprises:

determining the SRS transmission beam based at least in part on one or more SRS transmission beam parameters.
The method of claim 10, wherein the one or more SRS transmission beam parameters are indicated in the SRS resource configuration.
The method of claim 10, wherein the one or more SRS transmission beam parameters are programmed or configured at the UE and are based at least in part on a standard.
The method of claim 10, wherein the one or more SRS transmission beam parameters comprise:

a first parameter indicating that a beam correlation between the SRS transmission beam and a reference SRS transmission beam of the one or more SRS transmission beams is to satisfy a beam correlation threshold; and

a second parameter indicating that the SRS transmission beam is to generate zero interference strength on access links associated with the one or more non-target TRPs.
The method of claim 10, wherein the one or more SRS transmission beam parameters comprise:

a first parameter indicating that a beam correlation between the SRS transmission beam and a reference SRS transmission beam of the one or more SRS transmission beams is to satisfy a beam correlation threshold; and

a second parameter indicating an interference strength of the SRS transmission beam for access links associated with the one or more non-target TRPs that satisfies an interference strength threshold.
The method of claim 14, further comprising:

determining a beamformed downlink channel gain on non-target downlinks associated with the one or more non-target TRPs;

determining the interference strength of the SRS transmission beam based at least in part on reciprocity between the interference strength of the SRS transmission beam and the beamformed downlink channel gain on the non-target downlinks associated with the one or more non-target TRPs; and

determining whether the interference strength of the SRS transmission satisfies the interference strength threshold.
The method of claim 15, wherein determining the beamformed downlink channel gain on the access links associated with the one or more non-target TRPs comprises:

identifying respective transmission powers for each of the one or more reference signals; and

determining the beamformed downlink channel gain on the non-target downlinks associated with the one or more non-target TRPs based at least in part on the respective transmission powers for each of the one or more reference signals.
The method of claim 16, wherein identifying the respective transmission powers comprises:

identifying the respective transmission powers based at least in part on an indication of the respective transmission powers in the SRS resource configuration.
The method of claim 16, wherein identifying the respective transmission powers comprises:

identifying the respective transmission powers based at least in part on the respective transmission powers being programmed or configured at the UE.
The method of claim 1, wherein determining the SRS transmission beam comprises:

determining, for a non-target TRP of the one or more non-target TRPs, an uplink channel response matrix based at least in part on a reference signal, of the one or more reference signals, transmitted from the non-target TRP;

determining an orthogonal projection matrix of the uplink channel response matrix;

determining a projection of a beamforming weight vector of a reference SRS transmission beam, of the one or more SRS transmission beams, associated with the target TRP onto the orthogonal projection matrix; and

determining a column vector as the beamforming weight vector of the SRS transmission beam, based at least in part on the projection of the vector of the reference SRS transmission beam onto the orthogonal projection matrix.
The method of claim 1, wherein determining the SRS transmission beam comprises:

determining respective correlation coefficients between one or more reference SRS transmission beams and the one or more SRS transmission beams;

determining one or more downlink beams based on the one or more reference SRS transmission beams;

sweeping the one or more downlink beams to receive the one or more reference signals;

determining respective beamformed downlink channel gains for each of the one or more downlink beams based at least in part on the one or more reference signals;

determining respective uplink interference strengths for the one or more reference SRS transmission beams based at least in part on:

the respective beamformed downlink channel gains, and

reciprocity between the one or more reference SRS transmission beams and the one or more downlink beams; and

determining the SRS transmission beam based at least in part on the respective uplink interference strengths and the respective correlation coefficients.
A user equipment (UE) for wireless communication, comprising:

a memory; and

one or more processors operatively coupled to the memory, the memory and the one or more processors configured to:

receive a sounding reference signal (SRS) resource configuration indicating an SRS resource; and

determine an SRS transmission beam, for transmission of an SRS in the SRS resource to a target transmit receive point (TRP) based at least in part on:

one or more SRS transmission beams associated with the target TRP, and

one or more reference signals transmitted from one or more non-target TRPs.
The UE of claim 21, wherein the one or more processors are further configured to:

transmit, to the target TRP, the SRS in the SRS resource using the SRS transmission beam;

receive an uplink scheduling grant based at least in part on the SRS; and

transmit, based at least in part on the uplink scheduling grant, an uplink data communication using the SRS transmission beam.
The UE of claim 21, wherein the one or more SRS transmission beams are associated with another, previously configured, SRS resource for the target TRP;

wherein the other SRS resource is associated with one or more SRS ports; and

wherein each of the one or more SRS ports is associated with a respective SRS transmission beam of the one or more SRS transmission beams.
The UE of claim 21, wherein the one or more SRS transmission beams are identified in the SRS resource configuration.
The UE of claim 21, wherein the one or more processors are further configured to:

determine respective sets of beamforming weights for each of the one or more SRS transmission beams; and

generate a reference SRS transmission beam of the one or more SRS transmission beams based at least in part on:

a set of beamforming weights for the reference SRS transmission beam, and

an SRS port, of the one or more SRS ports, associated with the reference SRS transmission beam.
The UE of claim 21, wherein the one or more reference signals are identified in the SRS resource configuration.
The UE of claim 21, wherein the one or more processors are further configured to:

determine respective channel response matrixes for each of the one or more reference signals based at least in part on the SRS resource configuration; and

wherein the one or more processors, when determining the SRS transmission beam comprises, are configured to:

determine the SRS transmission beam based at least in part on the respective channel response matrixes.
The UE of claim 27, wherein the one or more reference signals comprise at least one of:

a channel state information reference signal,

a demodulation reference signal, or

a synchronization signal block.
The UE of claim 21, wherein the one or more processors, when receiving the SRS resource configuration, are configured to:

receive the SRS resource configuration in at least one of:

one or more radio resource control communications,

one or more medium access control control element communications, or

one or more downlink control information communications.
The UE of claim 21, wherein the one or more processors, when determining the SRS transmission beam, are configured to:

determine the SRS transmission beam based at least in part on one or more SRS transmission beam parameters.
The UE of claim 30, wherein the one or more SRS transmission beam parameters are indicated in the SRS resource configuration.
The UE of claim 30, wherein the one or more SRS transmission beam parameters are programmed or configured at the UE and are based at least in part on a standard.
The UE of claim 30, wherein the one or more SRS transmission beam parameters comprise:

a first parameter indicating that a beam correlation between the SRS transmission beam and a reference SRS transmission beam of the one or more SRS transmission beams is to satisfy a beam correlation threshold; and

a second parameter indicating that the SRS transmission beam is to generate zero interference strength on access links associated with the one or more non-target TRPs.
The UE of claim 30, wherein the one or more SRS transmission beam parameters comprise:

a first parameter indicating that a beam correlation between the SRS transmission beam and a reference SRS transmission beam of the one or more SRS transmission beams is to satisfy a beam correlation threshold; and

a second parameter indicating an interference strength of the SRS transmission beam for access links associated with the one or more non-target TRPs that satisfies an interference strength threshold.
The UE of claim 34, wherein the one or more processors are further configured to:

determine a beamformed downlink channel gain on non-target downlinks associated with the one or more non-target TRPs;

determine the interference strength of the SRS transmission beam based at least in part on reciprocity between the interference strength of the SRS transmission beam and the beamformed downlink channel gain on the non-target downlinks associated with the one or more non-target TRPs; and

determine whether the interference strength of the SRS transmission satisfies the interference strength threshold.
The UE of claim 35, wherein the one or more processors, when determining the beamformed downlink channel gain on the access links associated with the one or more non-target TRPs, are configured to:

identify respective transmission powers for each of the one or more reference signals; and

determine the beamformed downlink channel gain on the non-target downlinks associated with the one or more non-target TRPs based at least in part on the respective transmission powers for each of the one or more reference signals.
The UE of claim 36, wherein the one or more processors, when identifying the respective transmission powers, are configured to:

identify the respective transmission powers based at least in part on an indication of the respective transmission powers in the SRS resource configuration.
The UE of claim 36, wherein the one or more processors, when identifying the respective transmission powers, are configured to:

identify the respective transmission powers based at least in part on the respective transmission powers being programmed or configured at the UE.
The UE of claim 21, wherein the one or more processors, when determining the SRS transmission beam, are configured to:

determine, for a non-target TRP of the one or more non-target TRPs, an uplink channel response matrix based at least in part on a reference signal, of the one or more reference signals, transmitted from the non-target TRP;

determine an orthogonal projection matrix of the uplink channel response matrix;

determine a projection of a beamforming weight vector of a reference SRS transmission beam, of the one or more SRS transmission beams, associated with the target TRP onto the orthogonal projection matrix; and

determine a column vector as the beamforming weight vector of the SRS transmission beam, based at least in part on the projection of the vector of the reference SRS transmission beam onto the orthogonal projection matrix.
The UE of claim 21, wherein the one or more processors, when determining the SRS transmission beam, are configured to:

determine respective correlation coefficients between one or more reference SRS transmission beams and the one or more SRS transmission beams;

determine one or more downlink beams based on the one or more reference SRS transmission beams;

sweep the one or more downlink beams to receive the one or more reference signals;

determine respective beamformed downlink channel gains for each of the one or more downlink beams based at least in part on the one or more reference signals;

determine respective uplink interference strengths for the one or more reference SRS transmission beams based at least in part on:

the respective beamformed downlink channel gains, and

reciprocity between the one or more reference SRS transmission beams and the one or more downlink beams; and

determine the SRS transmission beam based at least in part on the respective uplink interference strengths and the respective correlation coefficients.
A non-transitory computer-readable medium storing one or more instructions for wireless communication, the one or more instructions comprising:

one or more instructions that, when executed by one or more processors of a user equipment (UE) , cause the one or more processors to:

receive a sounding reference signal (SRS) resource configuration indicating an SRS resource; and

determine an SRS transmission beam, for transmission of an SRS in the SRS resource to a target transmit receive point (TRP) based at least in part on:

one or more SRS transmission beams associated with the target TRP, and

one or more reference signals transmitted from one or more non-target TRPs.
The non-transitory computer-readable medium of claim 41, wherein the one or more instructions, when executed by the one or more processors, further cause the one or more processors to:

transmit, to the target TRP, the SRS in the SRS resource using the SRS transmission beam;

receive an uplink scheduling grant based at least in part on the SRS; and

transmit, based at least in part on the uplink scheduling grant, an uplink data communication using the SRS transmission beam.
The non-transitory computer-readable medium of claim 41, wherein the one or more SRS transmission beams are associated with another, previously configured, SRS resource for the target TRP;

wherein the other SRS resource is associated with one or more SRS ports; and

wherein each of the one or more SRS ports is associated with a respective SRS transmission beam of the one or more SRS transmission beams.
The non-transitory computer-readable medium of claim 41, wherein the one or more SRS transmission beams are identified in the SRS resource configuration.
The non-transitory computer-readable medium of claim 41, wherein the one or more instructions, when executed by the one or more processors, further cause the one or more processors to:

determine respective sets of beamforming weights for each of the one or more SRS transmission beams; and

generate a reference SRS transmission beam of the one or more SRS transmission beams based at least in part on:

a set of beamforming weights for the reference SRS transmission beam, and

an SRS port, of the one or more SRS ports, associated with the reference SRS transmission beam.
The non-transitory computer-readable medium of claim 41, wherein the one or more reference signals are identified in the SRS resource configuration.
The non-transitory computer-readable medium of claim 41, wherein the one or more instructions, when executed by the one or more processors, further cause the one or more processors to:

determine respective channel response matrixes for each of the one or more reference signals based at least in part on the SRS resource configuration; and

wherein the one or more instructions, that cause the one or more processors to determine the SRS transmission beam, cause the one or more processors to:

determine the SRS transmission beam based at least in part on the respective channel response matrixes.
The non-transitory computer-readable medium of claim 47, wherein the one or more reference signals comprise at least one of:

a channel state information reference signal,

a demodulation reference signal, or

a synchronization signal block.
The non-transitory computer-readable medium of claim 41, wherein the one or more instructions, that cause the one or more processors to receiving the SRS resource configuration, cause the one or more processors to:

receive the SRS resource configuration in at least one of:

one or more radio resource control communications,

one or more medium access control control element communications, or

one or more downlink control information communications.
The non-transitory computer-readable medium of claim 41, wherein the one or more instructions, that cause the one or more processors to determining the SRS transmission beam, cause the one or more processors to:

determine the SRS transmission beam based at least in part on one or more SRS transmission beam parameters.
The non-transitory computer-readable medium of claim 50, wherein the one or more SRS transmission beam parameters are indicated in the SRS resource configuration.
The non-transitory computer-readable medium of claim 50, wherein the one or more SRS transmission beam parameters are programmed or configured at the UE and are based at least in part on a standard.
The non-transitory computer-readable medium of claim 50, wherein the one or more SRS transmission beam parameters comprise:

a first parameter indicating that a beam correlation between the SRS transmission beam and a reference SRS transmission beam of the one or more SRS transmission beams is to satisfy a beam correlation threshold; and

a second parameter indicating that the SRS transmission beam is to generate zero interference strength on access links associated with the one or more non-target TRPs.
The non-transitory computer-readable medium of claim 50, wherein the one or more SRS transmission beam parameters comprise:

a first parameter indicating that a beam correlation between the SRS transmission beam and a reference SRS transmission beam of the one or more SRS transmission beams is to satisfy a beam correlation threshold; and

a second parameter indicating an interference strength of the SRS transmission beam for access links associated with the one or more non-target TRPs that satisfies an interference strength threshold.
The non-transitory computer-readable medium of claim 54, wherein the one or more instructions, when executed by the one or more processors, further cause the one or more processors to:

determine a beamformed downlink channel gain on non-target downlinks associated with the one or more non-target TRPs;

determine the interference strength of the SRS transmission beam based at least in part on reciprocity between the interference strength of the SRS transmission beam and the beamformed downlink channel gain on the non-target downlinks associated with the one or more non-target TRPs; and

determine whether the interference strength of the SRS transmission satisfies the interference strength threshold.
The non-transitory computer-readable medium of claim 55, wherein the one or more instructions, that cause the one or more processors to determining the beamformed downlink channel gain on the access links associated with the one or more non-target TRPs, cause the one or more processors to:

identify respective transmission powers for each of the one or more reference signals; and

determine the beamformed downlink channel gain on the non-target downlinks associated with the one or more non-target TRPs based at least in part on the respective transmission powers for each of the one or more reference signals.
The non-transitory computer-readable medium of claim 56, wherein the one or more instructions, that cause the one or more processors to identifying the respective transmission powers, cause the one or more processors to:

identify the respective transmission powers based at least in part on an indication of the respective transmission powers in the SRS resource configuration.
The non-transitory computer-readable medium of claim 56, wherein the one or more instructions, that cause the one or more processors to identifying the respective transmission powers, cause the one or more processors to:

identify the respective transmission powers based at least in part on the respective transmission powers being programmed or configured at the UE.
The non-transitory computer-readable medium of claim 41, wherein the one or more instructions, that cause the one or more processors to determining the SRS transmission beam, cause the one or more processors to:

determine, for a non-target TRP of the one or more non-target TRPs, an uplink channel response matrix based at least in part on a reference signal, of the one or more reference signals, transmitted from the non-target TRP;

determine an orthogonal projection matrix of the uplink channel response matrix;

determine a projection of a beamforming weight vector of a reference SRS transmission beam, of the one or more SRS transmission beams, associated with the target TRP onto the orthogonal projection matrix; and

determine a column vector as the beamforming weight vector of the SRS transmission beam, based at least in part on the projection of the vector of the reference SRS transmission beam onto the orthogonal projection matrix.
The non-transitory computer-readable medium of claim 41, wherein the one or more instructions, that cause the one or more processors to determining the SRS transmission beam, cause the one or more processors to:

determine respective correlation coefficients between one or more reference SRS transmission beams and the one or more SRS transmission beams;

determine one or more downlink beams based on the one or more reference SRS transmission beams;

sweep the one or more downlink beams to receive the one or more reference signals;

determine respective beamformed downlink channel gains for each of the one or more downlink beams based at least in part on the one or more reference signals;

determine respective uplink interference strengths for the one or more reference SRS transmission beams based at least in part on:

the respective beamformed downlink channel gains, and

reciprocity between the one or more reference SRS transmission beams and the one or more downlink beams; and

determine the SRS transmission beam based at least in part on the respective uplink interference strengths and the respective correlation coefficients.
An apparatus for wireless communication, comprising:

means for receiving a sounding reference signal (SRS) resource configuration indicating an SRS resource; and

means for determining an SRS transmission beam, for transmission of an SRS in the SRS resource to a target transmit receive point (TRP) based at least in part on:

one or more SRS transmission beams associated with the target TRP, and

one or more reference signals transmitted from one or more non-target TRPs.
The apparatus of claim 61, further comprising:

means for transmitting, to the target TRP, the SRS in the SRS resource using the SRS transmission beam;

means for receiving an uplink scheduling grant based at least in part on the SRS; and

means for transmitting, based at least in part on the uplink scheduling grant, an uplink data communication using the SRS transmission beam.
The apparatus of claim 61, wherein the one or more SRS transmission beams are associated with another, previously configured, SRS resource for the target TRP;

wherein the other SRS resource is associated with one or more SRS ports; and

wherein each of the one or more SRS ports is associated with a respective SRS transmission beam of the one or more SRS transmission beams.
The apparatus of claim 61, wherein the one or more SRS transmission beams are identified in the SRS resource configuration.
The apparatus of claim 61, further comprising:

means for determining respective sets of beamforming weights for each of the one or more SRS transmission beams; and

means for generating a reference SRS transmission beam of the one or more SRS transmission beams based at least in part on:

a set of beamforming weights for the reference SRS transmission beam, and

an SRS port, of the one or more SRS ports, associated with the reference SRS transmission beam.
The apparatus of claim 61, wherein the one or more reference signals are identified in the SRS resource configuration.
The apparatus of claim 61, further comprising:

means for determining respective channel response matrixes for each of the one or more reference signals based at least in part on the SRS resource configuration; and

wherein the means for determining the SRS transmission beam comprises:

means for determining the SRS transmission beam based at least in part on the respective channel response matrixes.
The apparatus of claim 67, wherein the one or more reference signals comprise at least one of:

a channel state information reference signal,

a demodulation reference signal, or

a synchronization signal block.
The apparatus of claim 61, wherein receiving the SRS resource configuration comprises:

means for receiving the SRS resource configuration in at least one of:

one or more radio resource control communications,

one or more medium access control control element communications, or

one or more downlink control information communications.
The apparatus of claim 61, wherein the means for determining the SRS transmission beam comprises:

means for determining the SRS transmission beam based at least in part on one or more SRS transmission beam parameters.
The apparatus of claim 70, wherein the one or more SRS transmission beam parameters are indicated in the SRS resource configuration.
The apparatus of claim 70, wherein the one or more SRS transmission beam parameters are programmed or configured at the apparatus and are based at least in part on a standard.
The apparatus of claim 70, wherein the one or more SRS transmission beam parameters comprise:

a first parameter indicating that a beam correlation between the SRS transmission beam and a reference SRS transmission beam of the one or more SRS transmission beams is to satisfy a beam correlation threshold; and

a second parameter indicating that the SRS transmission beam is to generate zero interference strength on access links associated with the one or more non-target TRPs.
The apparatus of claim 70, wherein the one or more SRS transmission beam parameters comprise:

a first parameter indicating that a beam correlation between the SRS transmission beam and a reference SRS transmission beam of the one or more SRS transmission beams is to satisfy a beam correlation threshold; and

a second parameter indicating an interference strength of the SRS transmission beam for access links associated with the one or more non-target TRPs that satisfies an interference strength threshold.
The apparatus of claim 74, further comprising:

means for determining a beamformed downlink channel gain on non-target downlinks associated with the one or more non-target TRPs;

means for determining the interference strength of the SRS transmission beam based at least in part on reciprocity between the interference strength of the SRS transmission beam and the beamformed downlink channel gain on the non-target downlinks associated with the one or more non-target TRPs; and

means for determining whether the interference strength of the SRS transmission satisfies the interference strength threshold.
The apparatus of claim 75, wherein the means for determining the beamformed downlink channel gain on the access links associated with the one or more non-target TRPs comprises:

means for identifying respective transmission powers for each of the one or more reference signals; and

means for determining the beamformed downlink channel gain on the non-target downlinks associated with the one or more non-target TRPs based at least in part on the respective transmission powers for each of the one or more reference signals.
The apparatus of claim 76, wherein the means for identifying the respective transmission powers comprises:

means for identifying the respective transmission powers based at least in part on an indication of the respective transmission powers in the SRS resource configuration.
The apparatus of claim 76, wherein the means for identifying the respective transmission powers comprises:

means for identifying the respective transmission powers based at least in part on the respective transmission powers being programmed or configured at the apparatus.
The apparatus of claim 61, wherein the means for determining the SRS transmission beam comprises:

means for determining, for a non-target TRP of the one or more non-target TRPs, an uplink channel response matrix based at least in part on a reference signal, of the one or more reference signals, transmitted from the non-target TRP;

means for determining an orthogonal projection matrix of the uplink channel response matrix;

means for determining a projection of a beamforming weight vector of a reference SRS transmission beam, of the one or more SRS transmission beams, associated with the target TRP onto the orthogonal projection matrix; and

means for determining a column vector as the beamforming weight vector of the SRS transmission beam, based at least in part on the projection of the vector of the reference SRS transmission beam onto the orthogonal projection matrix.
The apparatus of claim 61, wherein the means for determining the SRS transmission beam comprises:

means for determining respective correlation coefficients between one or more reference SRS transmission beams and the one or more SRS transmission beams;

means for determining one or more downlink beams based on the one or more reference SRS transmission beams;

means for sweeping the one or more downlink beams to receive the one or more reference signals;

means for determining respective beamformed downlink channel gains for each of the one or more downlink beams based at least in part on the one or more reference signals;

means for determining respective uplink interference strengths for the one or more reference SRS transmission beams based at least in part on:

the respective beamformed downlink channel gains, and

reciprocity between the one or more reference SRS transmission beams and the one or more downlink beams; and

means for determining the SRS transmission beam based at least in part on the respective uplink interference strengths and the respective.