Interference mitigation by pseudo-random muting for sounding reference signals

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive, from a network entity, a configuration of at least one sounding reference signal (SRS) resource, wherein the configuration indicates a pseudo-random sequence for muting an SRS associated with the at least one SRS resource. The UE may transmit the SRS using the at least one SRS resource based at least in part on the pseudo-random sequence. Numerous other aspects are described.

FIELD OF THE DISCLOSURE

Aspects of the present disclosure generally relate to wireless communication and to techniques and apparatuses for interference mitigation by pseudo-random muting for sounding reference signals.

BACKGROUND

SUMMARY

Some aspects described herein relate to a method of wireless communication performed by a user equipment (UE). The method may include receiving, from a network entity, a configuration of at least one sounding reference signal (SRS) resource, wherein the configuration indicates a pseudo-random sequence for muting an SRS associated with the at least one SRS resource. The method may include transmitting the SRS using the at least one SRS resource based at least in part on the pseudo-random sequence.

Some aspects described herein relate to a method of wireless communication performed by a network entity. The method may include transmitting, to a UE, a configuration of at least one SRS resource, wherein the configuration indicates a pseudo-random sequence for muting an SRS associated with the at least one SRS resource. The method may include receiving, from the UE, the SRS via the at least one SRS resource based at least in part on the pseudo-random sequence.

Some aspects described herein relate to an apparatus for wireless communication at a UE. The apparatus may include a memory and one or more processors coupled to the memory. The one or more processors may be configured to receive, from a network entity, a configuration of at least one SRS resource, wherein the configuration indicates a pseudo-random sequence for muting an SRS associated with the at least one SRS resource. The one or more processors may be configured to transmit the SRS using the at least one SRS resource based at least in part on the pseudo-random sequence.

Some aspects described herein relate to an apparatus for wireless communication at a network entity. The apparatus may include a memory and one or more processors coupled to the memory. The one or more processors may be configured to transmit, to a UE, a configuration of at least one SRS resource, wherein the configuration indicates a pseudo-random sequence for muting an SRS associated with the at least one SRS resource. The one or more processors may be configured to receive, from the UE, the SRS via the at least one SRS resource based at least in part on the pseudo-random sequence.

Some aspects described herein relate to a non-transitory computer-readable medium that stores a set of instructions for wireless communication by a UE. The set of instructions, when executed by one or more processors of the UE, may cause the UE to receive, from a network entity, a configuration of at least one SRS resource, wherein the configuration indicates a pseudo-random sequence for muting an SRS associated with the at least one SRS resource. The set of instructions, when executed by one or more processors of the UE, may cause the UE to transmit the SRS using the at least one SRS resource based at least in part on the pseudo-random sequence.

Some aspects described herein relate to a non-transitory computer-readable medium that stores a set of instructions for wireless communication by a network entity. The set of instructions, when executed by one or more processors of the network entity, may cause the network entity to transmit, to a UE, a configuration of at least one SRS resource, wherein the configuration indicates a pseudo-random sequence for muting an SRS associated with the at least one SRS resource. The set of instructions, when executed by one or more processors of the network entity, may cause the network entity to receive, from the UE, the SRS via the at least one SRS resource based at least in part on the pseudo-random sequence.

Some aspects described herein relate to an apparatus for wireless communication. The apparatus may include means for receiving, from a network entity, a configuration of at least one SRS resource, wherein the configuration indicates a pseudo-random sequence for muting an SRS associated with the at least one SRS resource. The apparatus may include means for transmitting the SRS using the at least one SRS resource based at least in part on the pseudo-random sequence.

Some aspects described herein relate to an apparatus for wireless communication. The apparatus may include means for transmitting, to a UE, a configuration of at least one SRS resource, wherein the configuration indicates a pseudo-random sequence for muting an SRS associated with the at least one SRS resource. The apparatus may include means for receiving, from the UE, the SRS via the at least one SRS resource based at least in part on the pseudo-random sequence.

DETAILED DESCRIPTION

In some aspects, the UE120may include a communication manager140. As described in more detail elsewhere herein, the communication manager140may receive, from a network entity, a configuration of at least one sounding reference signal (SRS) resource, wherein the configuration indicates a pseudo-random sequence for muting an SRS associated with the at least one SRS resource; and transmit the SRS using the at least one SRS resource based at least in part on the pseudo-random sequence. Additionally, or alternatively, the communication manager140may perform one or more other operations described herein.

In some aspects, the network entity described elsewhere herein may correspond to the base station110. In such aspects, the network entity may include a communication manager150. As described in more detail elsewhere herein, the communication manager150may transmit, to a UE, a configuration of at least one SRS resource, wherein the configuration indicates a pseudo-random sequence for muting an SRS associated with the at least one SRS resource; and receive, from the UE, the SRS via the at least one SRS resource based at least in part on the pseudo-random sequence. Additionally, or alternatively, the communication manager150may perform one or more other operations described herein.

In some aspects, the UE120includes means for receiving, from a network entity, a configuration of at least one SRS resource, wherein the configuration indicates a pseudo-random sequence for muting an SRS associated with the at least one SRS resource; and/or means for transmitting the SRS using the at least one SRS resource based at least in part on the pseudo-random sequence. The means for the UE120to perform operations described herein may include, for example, one or more of communication manager140, antenna252, modem254, MIMO detector256, receive processor258, transmit processor264, TX MIMO processor266, controller/processor280, or memory282.

In some aspects, the network entity includes means for transmitting, to a UE, a configuration of at least one SRS resource, wherein the configuration indicates a pseudo-random sequence for muting an SRS associated with the at least one SRS resource; and/or means for receiving, from the UE, the SRS via the at least one SRS resource based at least in part on the pseudo-random sequence. In some aspects, the means for the network entity to perform operations described herein may include, for example, one or more of communication manager150, transmit processor220, TX MIMO processor230, modem232, antenna234, MIMO detector236, receive processor238, controller/processor240, memory242, or scheduler246.

FIG.3is a diagram illustrating an example300of an O-RAN architecture, in accordance with the present disclosure. As shown inFIG.3, the O-RAN architecture may include a centralized unit (CU)310that communicates with a core network320via a backhaul link. Furthermore, the CU310may communicate with one or more distributed units (DUs)330via respective midhaul links. The DUs330may each communicate with one or more radio units (RUs)340via respective fronthaul links, and the RUs340may each communicate with respective UEs120via radio frequency (RF) access links. The DUs330and the RUs340may also be referred to as O-RAN DUs (O-DUs)330and O-RAN RUs (O-RUs)340, respectively.

In some aspects, the DUs330and the RUs340may be implemented according to a functional split architecture in which functionality of a base station110(e.g., an eNB or a gNB) is provided by a DU330and one or more RUs340that communicate over a fronthaul link. Accordingly, as described herein, a base station110may include a DU330and one or more RUs340that may be co-located or geographically distributed. In some aspects, the DU330and the associated RU(s)340may communicate via a fronthaul link to exchange real-time control plane information via a lower layer split (LLS) control plane (LLS-C) interface, to exchange non-real-time management information via an LLS management plane (LLS-M) interface, and/or to exchange user plane information via an LLS user plane (LLS-U) interface.

Accordingly, the DU330may correspond to a logical unit that includes one or more base station functions to control the operation of one or more RUs340. For example, in some aspects, the DU330may host a radio link control (RLC) layer, a medium access control (MAC) layer, and one or more high physical (PHY) layers (e.g., forward error correction (FEC) encoding and decoding, scrambling, and/or modulation and demodulation) based at least in part on a lower layer functional split. Higher layer control functions, such as a packet data convergence protocol (PDCP), radio resource control (RRC), and/or service data adaptation protocol (SDAP), may be hosted by the CU310. The RU(s)340controlled by a DU330may correspond to logical nodes that host RF processing functions and low-PHY layer functions (e.g., fast Fourier transform (FFT), inverse FFT (iFFT), digital beamforming, and/or physical random access channel (PRACH) extraction and filtering) based at least in part on the lower layer functional split. Accordingly, in an O-RAN architecture, the RU(s)340handle all over the air (OTA) communication with a UE120, and real-time and non-real-time aspects of control and user plane communication with the RU(s)340are controlled by the corresponding DU330, which enables the DU(s)330and the CU310to be implemented in a cloud-based RAN architecture.

FIG.4is a diagram illustrating an example400of physical channels and reference signals in a wireless network, in accordance with the present disclosure. As shown inFIG.4, downlink channels and downlink reference signals may carry information from a base station110to a UE120, and uplink channels and uplink reference signals may carry information from a UE120to a base station110.

As shown, a downlink channel may include a physical downlink control channel (PDCCH) that carries downlink control information (DCI), a physical downlink shared channel (PDSCH) that carries downlink data, or a physical broadcast channel (PBCH) that carries system information, among other examples. In some aspects, PDSCH communications may be scheduled by PDCCH communications. As further shown, an uplink channel may include a physical uplink control channel (PUCCH) that carries uplink control information (UCI), a physical uplink shared channel (PUSCH) that carries uplink data, or a physical random access channel (PRACH) used for initial network access, among other examples. In some aspects, the UE120may transmit acknowledgement (ACK) or negative acknowledgement (NACK) feedback (e.g., ACK/NACK feedback or ACK/NACK information) in UCI on the PUCCH and/or the PUSCH.

As further shown, a downlink reference signal may include a synchronization signal block (SSB), a channel state information (CSI) reference signal (CSI-RS), a demodulation reference signal (DMRS), a positioning reference signal (PRS), or a phase tracking reference signal (PTRS), among other examples. As also shown, an uplink reference signal may include an SRS, a DMRS, or a PTRS, among other examples. Aspects of the SRS are described in more detail below in connection withFIGS.5and6.

An SSB may carry information used for initial network acquisition and synchronization, such as a primary synchronization signal (PSS), a secondary synchronization signal (SSS), a PBCH, and a PBCH DMRS. An SSB is sometimes referred to as a synchronization signal/PBCH (SS/PBCH) block. In some aspects, the base station110may transmit multiple SSBs on multiple corresponding beams, and the SSBs may be used for beam selection.

A CSI-RS may carry information used for downlink channel estimation (e.g., downlink CSI acquisition), which may be used for scheduling, link adaptation, or beam management, among other examples. The base station110may configure a set of CSI-RSs for the UE120, and the UE120may measure the configured set of CSI-RSs. Based at least in part on the measurements, the UE120may perform channel estimation and may report channel estimation parameters to the base station110(e.g., in a CSI report), such as a channel quality indicator (CQI), a precoding matrix indicator (PMI), a CSI-RS resource indicator (CRI), a layer indicator (LI), a rank indicator (RI), or a reference signal received power (RSRP), among other examples. The base station110may use the CSI report to select transmission parameters for downlink communications to the UE120, such as a number of transmission layers (e.g., a rank), a precoding matrix (e.g., a precoder), a modulation and coding scheme (MCS), or a refined downlink beam (e.g., using a beam refinement procedure or a beam management procedure), among other examples.

A DMRS may carry information used to estimate a radio channel for demodulation of an associated physical channel (e.g., PDCCH, PDSCH, PBCH, PUCCH, or PUSCH). The design and mapping of a DMRS may be specific to a physical channel for which the DMRS is used for estimation. DMRSs are UE-specific, can be beamformed, can be confined in a scheduled resource (e.g., rather than transmitted on a wideband), and can be transmitted only when necessary. As shown, DMRSs are used for both downlink communications and uplink communications.

A PTRS may carry information used to compensate for oscillator phase noise. Typically, the phase noise increases as the oscillator carrier frequency increases. Thus, PTRS can be utilized at high carrier frequencies, such as millimeter wave frequencies, to mitigate phase noise. The PTRS may be used to track the phase of the local oscillator and to enable suppression of phase noise and common phase error (CPE). As shown, PTRSs are used for both downlink communications (e.g., on the PDSCH) and uplink communications (e.g., on the PUSCH).

A PRS may carry information used to enable timing or ranging measurements of the UE120based on signals transmitted by the base station110to improve observed time difference of arrival (OTDOA) positioning performance. For example, a PRS may be a pseudo-random Quadrature Phase Shift Keying (QPSK) sequence mapped in diagonal patterns with shifts in frequency and time to avoid collision with cell-specific reference signals and control channels (e.g., a PDCCH). In general, a PRS may be designed to improve detectability by the UE120, which may need to detect downlink signals from multiple neighboring base stations in order to perform OTDOA-based positioning. Accordingly, the UE120may receive a PRS from multiple cells (e.g., a reference cell and one or more neighbor cells), and may report a reference signal time difference (RSTD) based on OTDOA measurements associated with the PRSs received from the multiple cells. In some aspects, the base station110may then calculate a position of the UE120based on the RSTD measurements reported by the UE120.

An SRS may carry information used for uplink channel estimation, which may be used for scheduling, link adaptation, precoder selection, or beam management, among other examples. The base station110may configure one or more SRS resource sets for the UE120, and the UE120may transmit SRSs on the configured SRS resource sets. An SRS resource set may have a configured usage, such as uplink CSI acquisition, downlink CSI acquisition for reciprocity-based operations, uplink beam management, among other examples. The base station110may measure the SRSs, may perform channel estimation based at least in part on the measurements, and may use the SRS measurements to configure communications with the UE120.

FIG.5is a diagram illustrating an example500of SRS resource sets, in accordance with the present disclosure.

A base station110may configure a UE120with one or more SRS resource sets to allocate resources for SRS transmissions by the UE120. For example, a configuration for SRS resource sets may be indicated in an RRC message (e.g., an RRC configuration message or an RRC reconfiguration message). As shown by reference number505, an SRS resource set may include one or more resources (e.g., shown as SRS resources), which may include time resources and/or frequency resources (e.g., a slot, a symbol, a resource block, and/or a periodicity for the time resources).

As shown by reference number510, an SRS resource may include one or more antenna ports on which an SRS is to be transmitted (e.g., in a time-frequency resource). Thus, a configuration for an SRS resource set may indicate one or more time-frequency resources in which an SRS is to be transmitted and may indicate one or more antenna ports on which the SRS is to be transmitted in those time-frequency resources. In some aspects, the configuration for an SRS resource set may indicate a use case (e.g., in an SRS-SetUse information element) for the SRS resource set. For example, an SRS resource set may have a use case of antenna switching, codebook, non-codebook, or beam management.

An antenna switching SRS resource set may be used to indicate downlink CSI with reciprocity between an uplink and downlink channel. For example, when there is reciprocity between an uplink channel and a downlink channel, a base station110may use an antenna switching SRS (e.g., an SRS transmitted using a resource of an antenna switching SRS resource set) to acquire downlink CSI (e.g., to determine a downlink precoder to be used to communicate with the UE120).

A codebook SRS resource set may be used to indicate uplink CSI when a base station110indicates an uplink precoder to the UE120. For example, when the base station110is configured to indicate an uplink precoder to the UE120(e.g., using a precoder codebook), the base station110may use a codebook SRS (e.g., an SRS transmitted using a resource of a codebook SRS resource set) to acquire uplink CSI (e.g., to determine an uplink precoder to be indicated to the UE120and used by the UE120to communicate with the base station110). In some aspects, virtual ports (e.g., a combination of two or more antenna ports) with a maximum transmit power may be supported at least for a codebook SRS.

A non-codebook SRS resource set may be used to indicate uplink CSI when the UE120selects an uplink precoder (e.g., instead of the base station110indicated an uplink precoder to be used by the UE120. For example, when the UE120is configured to select an uplink precoder, the base station110may use a non-codebook SRS (e.g., an SRS transmitted using a resource of a non-codebook SRS resource set) to acquire uplink CSI. In this case, the non-codebook SRS may be precoded using a precoder selected by the UE120(e.g., which may be indicated to the base station110).

A beam management SRS resource set may be used for indicating CSI for millimeter wave communications.

An SRS resource can be configured as periodic, semi-persistent (sometimes referred to as semi-persistent scheduling (SPS)), or aperiodic. A periodic SRS resource may be configured via a configuration message that indicates a periodicity of the SRS resource (e.g., a slot-level periodicity, where the SRS resources occurs every Y slots) and a slot offset. In some cases, a periodic SRS resource may always be activated, and may not be dynamically activated or deactivated. A semi-persistent SRS resource may also be configured via a configuration message that indicates a periodicity and a slot offset for the semi-persistent SRS resource, and may be dynamically activated and deactivated (e.g., using DCI or a control element (MAC-CE)). An aperiodic SRS resource may be triggered dynamically, such as via DCI (e.g., UE-specific DCI or group common DCI) or a MAC-CE.

In some aspects, the UE120may be configured with a mapping between SRS ports (e.g., antenna ports) and corresponding SRS resources. The UE120may transmit an SRS on a particular SRS resource using an SRS port indicated in the configuration. In some aspects, an SRS resource may span N adjacent symbols within a slot (e.g., where N equals 1, 2, or 4). The UE120may be configured with X SRS ports (e.g., where X≤4). In some aspects, each of the X SRS ports may be mapped to a corresponding symbol of the SRS resource and used for transmission of an SRS in that symbol.

As shown inFIG.5, in some aspects, different SRS resource sets indicated to the UE120(e.g., having different use cases) may overlap (e.g., in time and/or in frequency, such as in the same slot). For example, as shown by reference number515, a first SRS resource set (e.g., shown as SRS Resource Set1) is shown as having an antenna switching use case. As shown, this example antenna switching SRS resource set includes a first SRS resource (shown as SRS Resource A) and a second SRS resource (shown as SRS Resource B). Thus, antenna switching SRS may be transmitted in SRS Resource A (e.g., a first time-frequency resource) using antenna port0and antenna port1and may be transmitted in SRS Resource B (e.g., a second time-frequency resource) using antenna port2and antenna port3.

As shown by reference number520, a second SRS resource set (e.g., shown as SRS Resource Set2) may be a codebook use case. As shown, this example codebook SRS resource set includes only the first SRS resource (shown as SRS Resource A). Thus, codebook SRSs may be transmitted in SRS Resource A (e.g., the first time-frequency resource) using antenna port0and antenna port1. In this case, the UE120may not transmit codebook SRSs in SRS Resource B (e.g., the second time-frequency resource) using antenna port2and antenna port3.

In some aspects, multiple UEs may transmit SRSs using overlapping time and/or frequency resources, which may cause interference at a receiver (e.g., a base station110or other network entity). Accordingly, in some aspects, an SRS resource and/or an SRS resource set may be configured with a cyclic shift such that SRSs originating from multiple UEs are orthogonal to one another in order to reduce interference at a receiver caused by the overlapping SRSs. Aspects of overlapping SRSs are described in more detail in connection withFIG.6.

FIG.6is a diagram illustrating an example600of time/frequency resources associated with an SRS, in accordance with the present disclosure.

The time/frequency resources shown inFIG.6include one slot in the time domain, which includes fourteen OFDM symbols indexed0to13, and one resource block in the frequency domain, which includes twelve subcarriers indexed0to11. In some aspects, an SRS transmission may occupy one, two, or four OFDM symbols in the time domain, which may be located within the last six symbols of the slot (e.g., the OFDM symbols indexed8to13in the depicted example). Moreover, an SRS transmission may occupy up to 272 resource blocks in the frequency domain. However, an individual UE may not transmit the SRS on every subcarrier, but instead may use a transmission comb to select a specific set of subcarriers.

For example, the UE may select subcarriers using a configured transmission comb spacing (KTC) of 2, 4, or 8. A transmission comb spacing of 2 means that an individual UE transmits on every second subcarrier, as is illustrated in OFDM symbols8and9inFIG.6. A transmission comb spacing of 4 means that an individual UE transmits on every fourth subcarrier, as is illustrated in OFDM symbols11and12inFIG.6. And a transmission comb spacing of 8 means that an individual UE transmits on every eighth subcarrier, as is illustrated in OFDM symbol13inFIG.6. An SRS resource may also be configured with a comb offset (sometimes referred to as Comb Offset, orkTC), which determines a starting resource element for the SRS. The comb offset may be configured as 0, 1, . . . , KTC−1 per SRS resource. For example, a first SRS resource in OFDM symbols8and9inFIG.6is configured with a transmission comb spacing of 2 and a comb offset of 0, a second SRS resource in OFDM symbols8and9is configured with a transmission comb spacing of 2 and a comb offset of 1, a third SRS resource in OFDM symbols11and12is configured with a transmission comb spacing of 4 and a comb offset of 0, a fourth SRS resource in OFDM symbols11and12is configured with a transmission comb spacing of 4 and a comb offset of 2, and a fifth SRS resource in OFDM symbol13is configured with a transmission comb spacing of 8 and a comb offset of 3.

Each transmission comb allows multiple groups of UEs to be frequency multiplexed within a given OFDM symbol. For example, a transmission comb spacing of 2 permits two groups of UEs to be frequency multiplexed with a single subcarrier offset between the two groups, as is shown in OFDM symbols8and9. A transmission comb spacing of 4 permits up to four groups of UEs to be frequency multiplexed within an OFDM symbol. And a transmission comb spacing of 8 permits up to eight groups of UEs to be frequency multiplexed within an OFDM symbol. As transmission comb spacing increases, the quality of the SRS measurements may be reduced because fewer resource elements are used to transmit the SRS.

Moreover, multiple SRSs may be sent in a given resource element (e.g., a group of UEs may utilize the same SRS resource) because each UE may be configured to transmit, as the SRS, a base sequence (e.g., a Zadoff-Chu sequence) with a specific cyclic shift. A length of the base sequence may be equal to a number of allocated resource elements for the SRS, and thus is dependent on the number of resource blocks allocated for the SRS (which may be up to 272 resource blocks) and the transmission comb spacing used (which may be 2, 4, or 8, as described). The base sequence may be selected such that, when each SRS is shifted according to the configured cyclic shift, the SRSs are orthogonalized Thus, a first SRS transmitted by a first UE according to a first cyclic shift will be orthogonal to a second SRS transmitted by a second UE according to a second cyclic shift, and thus may be transmitted using the same SRS resource with little interference at the receiver (e.g., base station or the like). The number of cyclic shifts (nSRScs,max) available for a given SRS resource may be dependent on the transmission comb spacing being used to transmit the SRS. For example, there may be eight cyclic shifts available when using a transmission comb spacing of 2, twelve cyclic shifts available when using a transmission comb spacing of 4, and six cyclic shifts available when using a transmission comb spacing of 6. Each UE may be configured with a cyclic shift index (nSRScs), which may be configured as 0, 1 . . . nSRScs,max−1 per SRS resource. In addition to different cyclic shifts being allocated to different UEs, when a UE is using multiple ports to transmit the SRS, different cyclic shifts may be allocated to different antenna ports (e.g., a UE which transmits the SRS from four antenna ports may be configured with four cyclic shifts).

In some aspects,ru,v(n) may be used to represent the base sequence to be transmitted as the SRS (with 0≤n<the length of the sequence), and a, may be a cyclic shift applied to the base sequence. In such aspects, the sequence transmitted by a UE may be equal to ejαin×ru,v(n) The cyclic shift, αi, may be equal to 2πnSRScs,i/nSRScs,max, with nSRScs,ibeing equal to

(nSRScs+nSRScs,max(pi-1⁢0⁢0⁢0)Na⁢pSRS)⁢mod⁢nSRScs,max,
with picorresponding to the antenna port number used to transmit the SRS (which may be 1000, 1001, 1002, or 1003), and with NapSRScorresponding to the number of allocated antenna ports (which sometimes may be referred to as nroJSRS-Ports). Thus, αimay be equal to {0, 1, 2, . . . 5, 6, 7}×2π/8 when using a transmission comb spacing of 2, may be equal to {0, 1, 2, . . . 9, 10, 11}×2π/12 when using a transmission comb spacing of 4, and may be equal to {0, 1, 2, 3, 4, 5}×2π/6 when using a transmission comb spacing of 8. Applying the cyclic shift to the base sequence in the manner described ensures mutual orthogonality among all antenna ports of a given SRS resource, and/or among different SRS resources of the same or different UEs.

Moreover, in some aspects, multiple base sequences (e.g., multipleru,v(n)) of flexible length may be available for use as the SRS. The particular sequence (e.g.,ru,v(n)) to be used by a UE may be determined using two steps. The first step selects a group of sequences. In some aspects, for a given length of SRS, there may be 30 groups of sequences, and these groups may be indexed using the variable u (e.g., u∈{0, 1, . . . , 29). The second step selects a sequence from within the group. Each group may include one sequence for sequences having a length less than 72, indexed as v=0, and may include two sequences for sequences having a length greater than or equal to 72, indexed as v∈{1, 2}. In some aspects, different base sequences (different (u, v)) may not be completely orthogonal but may nonetheless exhibit low cross-correlation such that interference between SRSs of different base sequences at the receiver is low.

The group, u, may be selected according to the equation u=(fgh(ns,fμ,l′)+nIDSRS) mod 30, where nIDSRSis an SRS sequence identity configured per SRS resource, and the component fgh(ns,fμ,l′) is dependent on whether group or sequence hopping is configured for the SRS resource, which may be indicated using a group or sequence hopping parameter (sometimes referred to as groupOrSequenceHopping). Group or sequence hopping may be used to pseudo-randomly switch between groups of sequences used for an SRS resource (e.g., u) or to pseudo-randomly switch between sequences within groups used for an SRS resource (e.g., v) in an effort to randomize interference at the receiver. If the group or sequence hopping parameter (e.g., groupOrSequenceHopping) indicates that neither group nor sequence hopping is to be utilized, fgh(ns,fμ,l′)=0 and v=0, and thus the group index only depends on the SRS sequence identity (e.g., u=nIDSRSmod 30). In such aspects, the base sequence is fixed in all OFDM symbols in all SRS slots for the SRS transmission in that SRS resource. Thus, for such aspects, a network entity (e.g., a base station) configuring one or more SRS resources may utilize interference planning techniques to minimize interference at the receiver, such as carefully assigning respective SRS sequence identities (e.g., nIDSRS) to different SRS resources of different UEs to avoid interference at the receiver (e.g., neighboring cells may be configured with values that generate different results from nIDSRSmod 30 to ensure that neighboring cells use different groups of sequences).

If the group or sequence hopping parameter (e.g., groupOrSequenceHopping) indicates that group hopping should be utilized, then v=0 while fgh(ns,fμ,l′) generates a pseudo-random result dependent on slot and symbol timing, with ns,fu, corresponding to the slot number within the radio frame for subcarrier spacing u, and1′ corresponding to a symbol number within the slot. More particularly, fgh(ns,fμ,l′)=(Σm=07c(8(ns,fμNsymbslot+l0+l′)+m)×2m) mod 30, where c(i) is a pseudo-random sequence that is initialized as cint=nIDSRSat the beginning of each radio frame.

If the group or sequence hopping parameter (e.g., groupOrSequenceHopping) indicates that sequence hopping should be utilized, then fgh(ns,fμ,l′)=0 (e.g., the group index only depends on the SRS sequence identity (e.g., u=nIDSRSmod 30)) while v is based upon a pseudo-random result dependent on slot and symbol timing. More particularly,

v={c⁡(ns,fμ⁢Nsymbslot+l0+l′)Msc,bSRS≥6⁢NscR⁢B0othe⁢r⁢w⁢i⁢s⁢e,
where c(i) is a pseudo-random sequence that is initialized as cinit=nIDSRSat the beginning of each radio frame.

Moreover, in some aspects, frequency hopping may be used to pseudo-randomly switch between frequency bands used to transmit the SRS, also in an effort to randomize interference at the receiver. More particularly, when the SRS spans less than a maximum bandwidth for SRS transmissions (e.g., 272 resource blocks), then an SRS resource may be configured with frequency hopping such that the SRS is transmitted using different portions (e.g., different frequency hops) of the SRS bandwidth.

Although the interference planning, group hopping, sequence hopping, and/or frequency hopping techniques described above may reduce and/or randomize some SRS interference at a receiver, SRSs may nonetheless still interfere with one another. For example, in coherent joint transmission (CJT) schemes, one or more UEs are coherently served by multiple TRPs (e.g., a cluster of TRPs), and thus the network may need information about channels between each TRP and a given UE in order to select transmission weights or other transmission parameters. Accordingly, each TRP of the multiple TRPs may need to receive SRS transmissions from a given UE, requiring the UE to transmit an SRS transmission with a large amount of power, thus increasing the likelihood of the SRS transmission reaching other network entities and causing interference. This may be particularly problematic when a large number of CJT UEs are near to one another, requiring multiple UEs to send SRS transmissions on the same OFDM symbols, thus increasing the likelihood of inter-cell and/or inter-cluster interference at the various receivers. In such scenarios, the above interference mitigation techniques may insufficiently mitigate SRS interference, leading to degraded SRS reception and channel quality, and overall poor link performance including high latency, low throughput, and link failure.

Some techniques and apparatuses described herein enable reduced SRS interference by pseudo-randomly muting SRS transmissions. For example, in some aspects, an SRS resource may be configured with a pseudo-random sequence for muting an SRS associated with the SRS resource, and the UE may transmit the SRS using the SRS resource based at least in part on the pseudo-random sequence. The pseudo-random sequence may be used to determine whether, at a given time, the UE should transmit the SRS (e.g., the SRS should not be muted) or not transmit the SRS (e.g., the SRS should be muted). In some aspects, the UE may determine whether or not to transmit the SRS based at least in part on performing a modulo operation between a pseudo-random number associated with the pseudo-random sequence and an integer and/or by comparing a result of the modulo operation between the pseudo-random number and the integer to a threshold. The pseudo-random sequence may be a function of time and, in some aspects, may be a function of one or more additional parameters to increase randomness, such as one or more of a comb offset index, a cyclic shift index, or an SRS sequence index (e.g., a group index or sequence index within the group) associated with the SRS resource. Pseudo-randomly muting SRS transmissions may beneficially decrease interference levels at a receiver because, at a given time, SRSs for some UEs may be muted, thus decreasing SRS density in a given resource, and/or because different combinations of UEs may simultaneously transmit SRSs in different transmission instances (e.g., in different slots and/or/symbols), avoiding consistent SRS interference at the receiver. As a result, SRS interference may be further mitigated as compared to group hopping, sequence hopping, frequency hopping, and similar techniques, leading to improved SRS reception and channel quality, including lower latency, higher throughput, and increased coverage.

FIG.7is a diagram illustrating an example700associated with interference mitigation by pseudo-random muting for SRSs, in accordance with the present disclosure. As shown inFIG.7, a UE705and a network entity710may communicate with one another. In some aspects, the UE705may correspond to the UE120, and the network entity710may correspond to any of the network entities described herein, such as a base station110, a TRP, a CU310, a DU330, an RU340, or a similar network entity.

As shown by reference number715, the UE705may receive, from the network entity710, a configuration of at least one SRS resource, wherein the configuration indicates a pseudo-random sequence (sometimes referred to as c(⋅)) for muting an SRS associated with the at least one SRS resource. In some aspects, the configuration indicated by reference number715may be received via an RRC message. Moreover, the configuration indicated by reference number715may be associated with an SRS resource and/or an SRS resource set. That is, in some aspects, the configuration of the at least one SRS resource is associated with a single SRS resource (such as one of SRS Resource A or SRS resource B described in connection withFIG.5), while in some other aspects, the configuration of the at least one SRS resource is associated with an SRS resource set including multiple SRS resources (such as one of SRS resource set1or SRS resource set2described in connection withFIG.5). The pseudo-random sequence may be used to indicate to the UE705whether or not the UE705should transmit the SRS at a particular time, as described in more detail below in connection with reference numbers725and730.

As shown by reference number720, in some aspects, the UE705and/or the network entity710may initialize the pseudo-random sequence (e.g., c(⋅)) at the beginning of each radio frame associated with the SRS transmission. In some aspects, the pseudo-random sequence may be initialized based at least in part on an SRS sequence identity configured for the at least one SRS resource (e.g., nIDSRSdescribed in connection withFIG.6). More particularly, the pseudo-random sequence may be initialized as cinitat the beginning of each radio frame, with cinit=nIDSRS. In some aspects, a network entity (e.g., network entity710) may configure the same SRS sequence identity (e.g., nIDSRS) for intra-cell or intra-cluster UEs, and may configure different SRS sequence identities for inter-cell or inter-cluster UEs. Thus, initializing the pseudo-random sequence based at least in part on the SRS sequence identity may beneficially result in inter-cell or inter-cluster interference randomization because UEs in different cells and/or clusters may not have the same outcome of muting and/or transmitting in all slots because the pseudo-random sequence initialization is not the same.

In some other aspects, the pseudo-random sequence may be initialized at a beginning of each radio frame based at least in part on a parameter configured by the network entity710(via RRC configuration or the like). For example, in some aspects, the UE705may receive, from the network entity710, a configuration of a pseudo-random sequence initialization parameter (which may be different than the SRS sequence identify), and the pseudo-random sequence may be initialized at a beginning of each radio frame based at least in part on the pseudo-random sequence initialization parameter. Beneficially, in such aspects, the pseudo-random sequence may be decoupled from the SRS sequence identity (e.g., nIDSRS), further randomizing SRS interference. In some aspects, a network entity (e.g., network entity710) may configure multiple UEs with the same pseudo-random sequence initialization parameter when, for example, the UEs are far from each other, such that they do not create interference to each other's intended receiver, and/or when the configured SRS parameters at each UE (e.g., KTC, nSRScs, nIDSRS, u, v, groupOrSequenceHopping, or the like) may result in orthogonalization. In some aspects, a network entity (e.g., network entity710) may configure different UEs with different pseudo-random sequence initialization parameters when, for example, the UEs are close to each other, such that they may create interference to each other's intended receiver, and/or when the configured SRS parameters at each UE (e.g., KTC, nSRScs, nIDSRS, u, v, groupOrSequenceHopping, or the like) may not result in orthogonalization Put another way, if two UEs have the same pseudo-random sequence initialization parameter, then at a given time both UEs may be muted or else both may be transmitting (e.g., there is no interference randomization). Thus, a network entity (e.g., network entity710) may only configure two UEs with the same pseudo-random sequence initialization parameter if the UEs' SRS transmissions do not create interference and/or if the UEs' SRS transmissions are orthogonal.

As shown by reference number725, the UE705may determine, at a given time, whether to transmit the SRS based at least in part on the pseudo-random sequence. In some aspects, the pseudo-random sequence may be used to generate a pseudo-random number, sometimes referred to as fmuting(t), at a particular time, t. The particular time, t, may correspond to a slot number or a symbol number of the SRS resource. Put another way, in some aspects, the UE705may determine whether to transmit the SRS using a slot granularity, while in some other aspects, the UE705may determine whether or to transmit the SRS using a symbol granularity.

When the determination is performed using a symbol granularity, the UE705may separately determine whether to transmit the SRS in each symbol of the SRS resource. For example, fmuting(ns,fμ,l′) may be equal to Σm=0M-1c(M×(ns,fμ,Nsymbslot+l0+l′)+m)×2m, with ns,fμcorresponding to the slot number with the radio frame for subcarrier spacing μ, l′ corresponding to the symbol number within the SRS resource, l0corresponding to the first symbol of the SRS resource in the slot (such that l0+l′ is equal to the symbol index within the slot), and c corresponding to the pseudo-random sequence. When the determination is performed using a slot granularity, the UE705may determine whether to transmit the SRS in each slot of the SRS resource. For example, fmuting(ns,fμ) may be equal to Σm=0M-1c(M×Nsymbslot+m)×2m, or Σm=0M-1c(M×(ns,fμNsymbslot+l0)+m)×2m. In such aspects, the random number (e.g., fmuting(t)) may be a function of the first symbol of the SRS resource within the slot, but may not change within the slot.

Moreover, in addition to being a function of time, the pseudo-random number (e.g., fmuting(t)) may be a function of one or more additional parameters in order to provide additional randomization to the SRS transmission. For example, in some aspects, the pseudo-random number may further be a function of a comb offset index associated with the at least one SRS resource (e.g., KTCdescribed in connection withFIG.6). Additionally, or alternatively, the pseudo-random number may further be a function of a cyclic shift index associated with the at least one SRS resource (e.g., nSRScsdescribed in connection withFIG.6). Additionally, or alternatively, the pseudo-random number may further be a function of an SRS sequence index associated with the at least one SRS resource (e.g., at least one of u or v described in connection withFIG.5). Put another way, the pseudo-random sequence may indicate whether to transmit the SRS as a function of at least one of a comb offset index associated with the at least one SRS resource, a cyclic shift index associated with the at least one SRS resource, or an SRS sequence index associated with the at least one SRS resource.

Additionally, or alternatively, when the at least one SRS resource is associated with multiple frequency hops, the pseudo-random sequence may indicate whether to transmit the SRS in each frequency hop, of the multiple frequency hops. Put another way, the pseudo-random number may further be a function of a frequency hop associated with the at least one SRS resource. More particularly, fmuting(ns,fμ, hop) may be equal to Σm=0M-1c(M×(ns,fμNsymbslot+l0hop)+m)×2m, with l0hopcorresponding to the hop index and/or the first symbol of the frequency hop.

In some aspects, the determination may be based at least in part on a result of a modulo operation between the pseudo-random number associated with the pseudo-random sequence at a given time (e.g., fmuting(t)) and an integer. For example, in some aspects, the integer may be 2. In such aspects, a result of the modulo operation between the pseudo-random number and the integer (e.g., fmutingmod 2) will be equal to either 0 or 1. A result of 0 or 1 may indicate that the UE705should transmit the SRS, while a result of the other one of 0 or 1 may indicate that the UE705should not transmit the SRS. In such aspects, the modulo operation may result in a muting probability of ½ (e.g., the UE705will mute the SRS transmission approximately half of the time). In some other aspects, the integer may be a different integer than 2 without departing from the scope of the disclosure.

Moreover, in some aspects, the pseudo-random sequence may further indicate whether to transmit the SRS based at least in part on a comparison of a result of the modulo operation between the pseudo-random number and the integer to the threshold value. Put another way, the determination shown by reference number725may further be based at least in part on comparing the result of the modulo operation between the pseudo-random number and the integer (e.g., K) with a threshold value (sometimes referred to as k). In some aspects, the threshold value may be less than the integer (e.g., k<K). Moreover, in some aspects, the result of the modulo operation between the pseudo-random number and the integer being greater than the threshold value (e.g., fmutingmod K>k) may indicate that the UE705should transmit the SRS, and the result of the modulo operation between the pseudo-random number and the integer being equal to or less than the threshold value (e.g., fmutingmod K≤k) may indicate that the UE705should not transmit the SRS. In such aspects, the modulo operation may result in a muting probability of k/K. Moreover, in some aspects, the values of K and k may be configured by the network entity710(such as for purposes of controlling the probability of muting per SRS resource), and thus may be transmitted to the UE705via an RRC message. For example, in some aspects, the values of K and k may be indicated via the configuration described in connection with reference number715, or via a similar configuration message.

As shown by reference number730, the UE705may transmit the SRS using the at least one SRS resource based at least in part on the pseudo-random sequence. More particularly, the UE705may periodically mute the SRS based at least in part on the pseudo-random sequence, as described above. This may include, at a given time, muting the SRS based at least in part on performing a modulo operation between the pseudo-random number (e.g., fmuting(t)) and an integer (e.g., K) and/or by comparing a result of the modulo operation between the pseudo-random number and the integer to a threshold value (e.g., k). As described, the pseudo-random number may be time dependent (e.g., dependent on a slot or symbol of the SRS resource) and/or may be dependent on one or more of a comb offset index, a cyclic shift index, or an SRS sequence index (e.g., a group index (e.g., u) or a sequence index (e.g., v)) associated with the at least one SRS resource. By pseudo-randomly muting SRS transmissions in the manner described, the UE705may beneficially decrease interference levels at the network entity710while creating varying combinations of SRSs received at the network entity, thus avoiding consistent SRS interference in the system. As a result, SRS interference may be further mitigated as compared to only group hopping, sequence hopping, and similar techniques, as discussed.

FIG.8is a diagram illustrating an example process800performed, for example, by a UE, in accordance with the present disclosure. Example process800is an example where the UE (e.g., UE705) performs operations associated with interference mitigation by pseudo-random muting for SRSs.

As shown inFIG.8, in some aspects, process800may include receiving, from a network entity, a configuration of at least one SRS resource, wherein the configuration indicates a pseudo-random sequence for muting an SRS associated with the at least one SRS resource (block810). For example, the UE (e.g., using communication manager1008and/or reception component1002, depicted inFIG.10) may receive, from a network entity, a configuration of at least one SRS resource, wherein the configuration indicates a pseudo-random sequence for muting an SRS associated with the at least one SRS resource, as described above.

As further shown inFIG.8, in some aspects, process800may include transmitting the SRS using the at least one SRS resource based at least in part on the pseudo-random sequence (block820). For example, the UE (e.g., using communication manager1008and/or transmission component1004, depicted inFIG.10) may transmit the SRS using the at least one SRS resource based at least in part on the pseudo-random sequence, as described above.

In a first aspect, the configuration of the at least one SRS resource is received via an RRC message.

In a second aspect, alone or in combination with the first aspect, the configuration of the at least one SRS resource is associated with a single SRS resource.

In a third aspect, alone or in combination with one or more of the first and second aspects, the configuration of the at least one SRS resource is associated with an SRS resource set including multiple SRS resources.

In a fourth aspect, alone or in combination with one or more of the first through third aspects, the pseudo-random sequence indicates whether to transmit the SRS as a function of time.

In a fifth aspect, alone or in combination with one or more of the first through fourth aspects, the pseudo-random sequence indicates whether to transmit the SRS as a function of time based at least in part on performing a modulo operation between a pseudo-random number associated with the pseudo-random sequence and an integer.

In a sixth aspect, alone or in combination with one or more of the first through fifth aspects, the integer is 2, a result of the modulo operation between the pseudo-random number and the integer being equal to one of 0 or 1 indicates that the UE should transmit the SRS, and the result of the modulo operation between the pseudo-random number and the integer being equal to the other one of 0 or 1 indicates that the UE should not transmit the SRS.

In a seventh aspect, alone or in combination with one or more of the first through sixth aspects, the pseudo-random sequence further indicates whether to transmit the SRS based at least in part on a comparison of a result of the modulo operation between the pseudo-random number and the integer to a threshold value.

In an eighth aspect, alone or in combination with one or more of the first through seventh aspects, the threshold value is less than the integer.

In a ninth aspect, alone or in combination with one or more of the first through eighth aspects, the result of the modulo operation between the pseudo-random number and the integer being greater than the threshold value indicates that the UE should transmit the SRS, and the result of the modulo operation between the pseudo-random number and the integer being equal to or less than the threshold value indicates that the UE should not transmit the SRS.

In a tenth aspect, alone or in combination with one or more of the first through ninth aspects, the pseudo-random sequence indicates whether to transmit the SRS as a function of at least one of a comb offset index associated with the at least one SRS resource, a cyclic shift index associated with the at least one SRS resource, or an SRS sequence index associated with the at least one SRS resource.

In an eleventh aspect, alone or in combination with one or more of the first through tenth aspects, each SRS resource of the at least one SRS resource includes multiple SRS symbols, and the pseudo-random sequence indicates whether to transmit the SRS in each SRS symbol, of the multiple SRS symbols.

In a twelfth aspect, alone or in combination with one or more of the first through eleventh aspects, each SRS resource of the at least one SRS resource is associated with a slot, and the pseudo-random sequence indicates whether to transmit the SRS in each slot.

In a thirteenth aspect, alone or in combination with one or more of the first through twelfth aspects, each SRS resource of the at least one SRS resource includes multiple frequency hops, and the pseudo-random sequence indicates whether to transmit the SRS in each frequency hop, of the multiple frequency hops.

In a fourteenth aspect, alone or in combination with one or more of the first through thirteenth aspects, the pseudo-random sequence is initialized at a beginning of each radio frame based at least in part on an SRS sequence identity configured for the at least one SRS resource.

In a fifteenth aspect, alone or in combination with one or more of the first through fourteenth aspects, process800includes receiving, from the network entity, a configuration of a pseudo-random sequence initialization parameter, wherein the pseudo-random sequence is initialized at a beginning of each radio frame based at least in part on the pseudo-random sequence initialization parameter.

FIG.9is a diagram illustrating an example process900performed, for example, by a network entity, in accordance with the present disclosure. Example process900is an example where the network entity (e.g., network entity710) performs operations associated with interference mitigation by pseudo-random muting for SRSs.

As shown inFIG.9, in some aspects, process900may include transmitting, to a UE, a configuration of at least one SRS resource, wherein the configuration indicates a pseudo-random sequence for muting an SRS associated with the at least one SRS resource (block910). For example, the network entity (e.g., using communication manager1108and/or transmission component1104, depicted inFIG.11) may transmit, to a UE, a configuration of at least one SRS resource, wherein the configuration indicates a pseudo-random sequence for muting an SRS associated with the at least one SRS resource, as described above.

As further shown inFIG.9, in some aspects, process900may include receiving, from the UE, the SRS via the at least one SRS resource based at least in part on the pseudo-random sequence (block920). For example, the network entity (e.g., using communication manager1108and/or reception component1102, depicted inFIG.11) may receive, from the UE, the SRS via the at least one SRS resource based at least in part on the pseudo-random sequence, as described above.

In a first aspect, the configuration of the at least one SRS resource is transmitted via an RRC message.

In a second aspect, alone or in combination with the first aspect, the configuration of the at least one SRS resource is associated with a single SRS resource.

In a third aspect, alone or in combination with one or more of the first and second aspects, the configuration of the at least one SRS resource is associated with an SRS resource set including multiple SRS resources.

In a fourth aspect, alone or in combination with one or more of the first through third aspects, the pseudo-random sequence indicates whether to transmit the SRS as a function of time.

In a fifth aspect, alone or in combination with one or more of the first through fourth aspects, the pseudo-random sequence indicates whether to transmit the SRS as a function of time based at least in part on a performance of a modulo operation between a pseudo-random number associated with the pseudo-random sequence and an integer.

In a sixth aspect, alone or in combination with one or more of the first through fifth aspects, the integer is 2, a result of the modulo operation between the pseudo-random number and the integer being equal to one of 0 or 1 indicates that the UE should transmit the SRS, and the result of the modulo operation between the pseudo-random number and the integer being equal to the other one of 0 or 1 indicates that the UE should not transmit the SRS.

In a seventh aspect, alone or in combination with one or more of the first through sixth aspects, the pseudo-random sequence further indicates whether to transmit the SRS based at least in part on a comparison of a result of the modulo operation between the pseudo-random number and the integer to a threshold value.

In an eighth aspect, alone or in combination with one or more of the first through seventh aspects, the threshold value is less than the integer.

In a ninth aspect, alone or in combination with one or more of the first through eighth aspects, the result of the modulo operation between the pseudo-random number and the integer being greater than the threshold value indicates that the UE should transmit the SRS, and the result of the modulo operation between the pseudo-random number and the integer being equal to or less than the threshold value indicates that the UE should not transmit the SRS.

In a tenth aspect, alone or in combination with one or more of the first through ninth aspects, the pseudo-random sequence indicates whether to transmit the SRS as a function of at least one of a comb offset index associated with the at least one SRS resource, a cyclic shift index associated with the at least one SRS resource, or an SRS sequence index associated with the at least one SRS resource.

In an eleventh aspect, alone or in combination with one or more of the first through tenth aspects, each SRS resource of the at least one SRS resource includes multiple SRS symbols, and the pseudo-random sequence indicates whether to transmit the SRS in each SRS symbol, of the multiple SRS symbols.

In a twelfth aspect, alone or in combination with one or more of the first through eleventh aspects, each SRS resource of the at least one SRS resource is associated with a slot, and the pseudo-random sequence indicates whether to transmit the SRS in each slot.

In a thirteenth aspect, alone or in combination with one or more of the first through twelfth aspects, each SRS resource of the at least one SRS resource includes multiple frequency hops, and the pseudo-random sequence indicates whether to transmit the SRS in each frequency hop, of the multiple frequency hops.

In a fourteenth aspect, alone or in combination with one or more of the first through thirteenth aspects, the pseudo-random sequence is initialized at a beginning of each radio frame based at least in part on an SRS sequence identity configured for the at least one SRS resource.

In a fifteenth aspect, alone or in combination with one or more of the first through fourteenth aspects, process900includes transmitting, to the UE, a configuration of a pseudo-random sequence initialization parameter, wherein the pseudo-random sequence is initialized at a beginning of each radio frame based at least in part on the pseudo-random sequence initialization parameter.

FIG.10is a diagram of an example apparatus1000for wireless communication, in accordance with the present invention. The apparatus1000may be a UE (e.g., UE705), or a UE may include the apparatus1000. In some aspects, the apparatus1000includes a reception component1002and a transmission component1004, which may be in communication with one another (for example, via one or more buses and/or one or more other components). As shown, the apparatus1000may communicate with another apparatus1006(such as a UE, a base station, or another wireless communication device) using the reception component1002and the transmission component1004. As further shown, the apparatus1000may include the communication manager1008(e.g., communication manager140). The communication manager1008may include an SRS component1010.

The reception component1002and/or the SRS component1010may receive, from a network entity, a configuration of at least one SRS resource, wherein the configuration indicates a pseudo-random sequence for muting an SRS associated with the at least one SRS resource. The transmission component1004and/or the SRS component1010may transmit the SRS using the at least one SRS resource based at least in part on the pseudo-random sequence.

The reception component1002may receive, from the network entity, a configuration of a pseudo-random sequence initialization parameter, wherein the pseudo-random sequence is initialized at a beginning of each radio frame based at least in part on the pseudo-random sequence initialization parameter.

FIG.11is a diagram of an example apparatus1100for wireless communication, in accordance with the present invention. The apparatus1100may be a network entity (e.g., network entity710), or a network entity may include the apparatus1100. In some aspects, the apparatus1100includes a reception component1102and a transmission component1104, which may be in communication with one another (for example, via one or more buses and/or one or more other components). As shown, the apparatus1100may communicate with another apparatus1106(such as a UE, a base station, or another wireless communication device) using the reception component1102and the transmission component1104. As further shown, the apparatus1100may include the communication manager1108(e.g., communication manager150). The communication manager1108may include one or more of a configuration component1110, or an SRS component1112, among other examples.

The transmission component1104, the configuration component1110, and/or the SRS component1112may transmit, to a UE, a configuration of at least one SRS resource, wherein the configuration indicates a pseudo-random sequence for muting an SRS associated with the at least one SRS resource. The reception component1102and/or the SRS component1112may receive, from the UE, the SRS via the at least one SRS resource based at least in part on the pseudo-random sequence.

The transmission component1104, the configuration component1110, and/or the SRS component1112may transmit, to the UE, a configuration of a pseudo-random sequence initialization parameter, wherein the pseudo-random sequence is initialized at a beginning of each radio frame based at least in part on the pseudo-random sequence initialization parameter.

Aspect 1: A method of wireless communication performed by a UE, comprising: receiving, from a network entity, a configuration of at least one SRS resource, wherein the configuration indicates a pseudo-random sequence for muting an SRS associated with the at least one SRS resource; and transmitting the SRS using the at least one SRS resource based at least in part on the pseudo-random sequence.

Aspect 2: The method of Aspect 1, wherein the configuration of the at least one SRS resource is received via an RRC message.

Aspect 3: The method of any of Aspects 1-2, wherein the configuration of the at least one SRS resource is associated with a single SRS resource.

Aspect 4: The method of any of Aspects 1-2, wherein the configuration of the at least one SRS resource is associated with an SRS resource set including multiple SRS resources.

Aspect 5: The method of any of Aspects 1-4, wherein the pseudo-random sequence indicates whether to transmit the SRS as a function of time.

Aspect 6: The method of Aspect 5, wherein the pseudo-random sequence indicates whether to transmit the SRS as a function of time based at least in part on performing a modulo operation between a pseudo-random number associated with the pseudo-random sequence and an integer.

Aspect 7: The method of Aspect 6, wherein the integer is 2, wherein a result of the modulo operation between the pseudo-random number and the integer being equal to one of 0 or 1 indicates that the UE should transmit the SRS, and wherein the result of the modulo operation between the pseudo-random number and the integer being equal to the other one of 0 or 1 indicates that the UE should not transmit the SRS.

Aspect 8: The method of Aspect 6, wherein the pseudo-random sequence further indicates whether to transmit the SRS based at least in part on a comparison of a result of the modulo operation between the pseudo-random number and the integer to a threshold value.

Aspect 9: The method of Aspect 8, wherein the threshold value is less than the integer.

Aspect 10: The method of Aspect 9, wherein the result of the modulo operation between the pseudo-random number and the integer being greater than the threshold value indicates that the UE should transmit the SRS, and wherein the result of the modulo operation between the pseudo-random number and the integer being equal to or less than the threshold value indicates that the UE should not transmit the SRS.

Aspect 11: The method of any of Aspects 1-10, wherein the pseudo-random sequence indicates whether to transmit the SRS as a function of at least one of a comb offset index associated with the at least one SRS resource, a cyclic shift index associated with the at least one SRS resource, or an SRS sequence index associated with the at least one SRS resource.

Aspect 12: The method of any of Aspects 1-11, wherein each SRS resource of the at least one SRS resource includes multiple SRS symbols, and wherein the pseudo-random sequence indicates whether to transmit the SRS in each SRS symbol, of the multiple SRS symbols.

Aspect 13: The method of any of Aspects 1-11, wherein each SRS resource of the at least one SRS resource is associated with a slot, and wherein the pseudo-random sequence indicates whether to transmit the SRS in each slot.

Aspect 14: The method of any of Aspects 1-13, wherein each SRS resource of the at least one SRS resource includes multiple frequency hops, and wherein the pseudo-random sequence indicates whether to transmit the SRS in each frequency hop, of the multiple frequency hops.

Aspect 15: The method of any of Aspects 1-14, wherein the pseudo-random sequence is initialized at a beginning of each radio frame based at least in part on an SRS sequence identity configured for the at least one SRS resource.

Aspect 16: The method of any of Aspects 1-14, further comprising receiving, from the network entity, a configuration of a pseudo-random sequence initialization parameter, wherein the pseudo-random sequence is initialized at a beginning of each radio frame based at least in part on the pseudo-random sequence initialization parameter.

Aspect 17: A method of wireless communication performed by a network entity, comprising: transmitting, to a UE, a configuration of at least one SRS resource, wherein the configuration indicates a pseudo-random sequence for muting an SRS associated with the at least one SRS resource; and receiving, from the UE, the SRS via the at least one SRS resource based at least in part on the pseudo-random sequence.

Aspect 18: The method of Aspect 17, wherein the configuration of the at least one SRS resource is transmitted via an RRC message.

Aspect 19: The method of any of Aspects 17-18, wherein the configuration of the at least one SRS resource is associated with a single SRS resource.

Aspect 20: The method of any of Aspects 17-18, wherein the configuration of the at least one SRS resource is associated with an SRS resource set including multiple SRS resources.

Aspect 21: The method of any of Aspects 17-20, wherein the pseudo-random sequence indicates whether to transmit the SRS as a function of time.

Aspect 22: The method of Aspect 21, wherein the pseudo-random sequence indicates whether to transmit the SRS as a function of time based at least in part on a performance of a modulo operation between a pseudo-random number associated with the pseudo-random sequence and an integer.

Aspect 23: The method of Aspect 22, wherein the integer is 2, wherein a result of the modulo operation between the pseudo-random number and the integer being equal to one of 0 or 1 indicates that the UE should transmit the SRS, and wherein the result of the modulo operation between the pseudo-random number and the integer being equal to the other one of 0 or 1 indicates that the UE should not transmit the SRS.

Aspect 24: The method of any of Aspects 22, wherein the pseudo-random sequence further indicates whether to transmit the SRS based at least in part on a comparison of a result of the modulo operation between the pseudo-random number and the integer to a threshold value.

Aspect 25: The method of Aspect 24, wherein the threshold value is less than the integer.

Aspect 26: The method of Aspect 25, wherein the result of the modulo operation between the pseudo-random number and the integer being greater than the threshold value indicates that the UE should transmit the SRS, and wherein the result of the modulo operation between the pseudo-random number and the integer being equal to or less than the threshold value indicates that the UE should not transmit the SRS.

Aspect 27: The method of any of Aspects 17-26, wherein the pseudo-random sequence indicates whether to transmit the SRS as a function of at least one of a comb offset index associated with the at least one SRS resource, a cyclic shift index associated with the at least one SRS resource, or an SRS sequence index associated with the at least one SRS resource.

Aspect 28: The method of any of Aspects 17-27, wherein each SRS resource of the at least one SRS resource includes multiple SRS symbols, and wherein the pseudo-random sequence indicates whether to transmit the SRS in each SRS symbol, of the multiple SRS symbols.

Aspect 29: The method of any of Aspects 17-27, wherein each SRS resource of the at least one SRS resource is associated with a slot, and wherein the pseudo-random sequence indicates whether to transmit the SRS in each slot.

Aspect 30: The method of any of Aspects 17-29, wherein each SRS resource of the at least one SRS resource includes multiple frequency hops, and wherein the pseudo-random sequence indicates whether to transmit the SRS in each frequency hop, of the multiple frequency hops.

Aspect 31: The method of any of Aspects 17-30, wherein the pseudo-random sequence is initialized at a beginning of each radio frame based at least in part on an SRS sequence identity configured for the at least one SRS resource.

Aspect 32: The method of any of Aspects 17-30, further comprising transmitting, to the UE, a configuration of a pseudo-random sequence initialization parameter, wherein the pseudo-random sequence is initialized at a beginning of each radio frame based at least in part on the pseudo-random sequence initialization parameter.