Uplink sounding reference signal precoder selection method for interference suppression

Abstract

The present disclosure provides a method for selecting a precoder for an uplink sounding reference signal (SRS) useful in multiple transmission and reception point (multiple TRP) situations. A user equipment (UE) device receives (450) a first channel state information reference signal (CSI-RS) from at least a first network entity, and also receives (455) a second CSI-RS from a second network entity. The UE device then receives (430), from the first network entity, control signaling indicating, for example, at least one set of SRS resources associated with the first CSI-RS or the second CSI-RS. The UE device transmits (470) the precoded SRS resources based on the received set of SRS resources and a precoder calculated based on the first CSI-RS and the second CSI-RS. In some cases, the UE apparatus determines (460) a precoder based on the first CSI-RS and the second CSI-RS such that the precoded SRS resources suppress interference with a signal received at the third network entity.

Description

Technical Field

[0001] The present disclosure generally relates to uplink transmission schemes. Background Art

[0002] The 3rd Generation Partnership Project (3GPP) is currently in the process of specifying a new radio interface called 5G New Radio (5G NR) and the Next Generation Packet Core Network (NG-CN or NGC). The 5G NR architecture will have three components: 5G Radio Access Network (5G-RAN), 5G Core Network (5GC), and User Equipment (UE). To facilitate the implementation of different data services and requirements, 3GPP 5G NR cellular networks support network slicing, which enables the reuse of virtualized and independent logical networks on the same physical network infrastructure.

[0003] NR supports uplink (e.g., physical uplink shared channel, PUSCH) multi-antenna precoding (e.g., in multiple layers). For massive input massive output (MIMO) scenarios, the UE device uses a precoding matrix to precode the signal after layer mapping. Generally, the UE device determines the precoding matrix using a codebook-based method or a non-codebook-based (NCB) method. In the codebook-based method, the base station (BS) provides instructions on the PDCCH to the UE device regarding the selection of the precoding matrix from the standard codebook. The BS selects the precoding matrix based on the sounding reference signal (SRS) from the antenna port of the UE device.

[0004] Unlike the codebook-based method, NCB-based uplink transmission does not rely on codebook selection. In the NCB scheme, the BS first sends a channel state information (CSI) reference signal (CSI-RS) to the UE device. The UE device measures the CSI-RS and calculates the precoder for SRS transmission to the BS. Using the precoding weights derived from the calculated precoder, the UE device sends a precoded beam to the BS on the SRS resources. The BS receives the precoder beam and uses the SRS resource set to determine the number of layers for the physical uplink shared channel (PUSCH) transmission. The BS also selects a subset of the precoded SRS resources to generate the number of layers. The BS then signals the UE device via downlink control information (DCI) to notify the UE device of the allocation of PUSCH resources in the UE device. The UE device uses the allocated resources to send PUSCH signals and demodulated reference signals (DMRS) according to the number of layers and precoding weights selected by the BS.

[0005] Multiple TRPs complicate the above-mentioned precoder selection or determination in NCB uplink transmission. Multiple TRPs enhance massive multiple-input multiple-output (MIMO) and enable a BS (e.g., a gNB) to use multiple TRPs to communicate with a UE device (e.g., each TRP can be considered as an antenna set, or another BS). Multiple TRPs can be transparent to each other and can operate jointly (e.g., the UE device treats them as the same and communication is not interrupted until all relevant TRPs fail). Conventionally, when a UE device wants to determine the uplink precoder for uplink NCB transmission, the UE device relies only on the downlink channel from one TRP: one CSI-RS from one TRP - and in a multi-TRP scenario where the UE device receives two or more CSI-RS from two or more TRPs (target TRPs), this determination will be insufficient. Summary of the invention

[0006] The present disclosure provides methods, systems and techniques for selecting a precoder for an uplink sounding reference signal (SRS) useful in a multi-transmission and reception point (multi-TRP) use case. A user equipment (UE) device sends a precoded SRS to two or more target reception TRPs when performing uplink transmission in a non-codebook (NCB) based scheme. The precoded SRS enhances the signal reception power in two or more target reception TRPs (referred to as target TRPs). The precoded SRS can also suppress interference to signals in non-target TRPs (referred to as victim TRPs) that are not intended recipients of the precoded SRS, thereby resulting in performance improvements at the victim TRPs.

[0007] When the UE device is to determine the uplink precoder for uplink NCB transmission, conventionally, the UE device only relies on the downlink channel from one TRP: one CSI-RS from one TRP-and in a multi-TRP scenario where the UE device receives two or more CSI-RS from two or more TRPs (target TRPs), this determination will be insufficient. For example, the UE device will not know how to select a precoder to generate good precoded channel energy in all target TRPs in two or more target TRPs. Further, in multi-TRP operation, an uplink signal (such as SRS) from the UE device may generate strong interference to some adjacent TRPs (victim TRPs) because the path loss between the UE device and the victim TRP may be less than the path loss between the UE device and the target TRP. In existing NCB-based transmission operations, the UE device does not consider the interference level at the victim TRP when determining the SRS precoder. Then, using conventional determination, the UE device may select a precoder that generates substantial interference to the victim TRP. Various aspects of the present disclosure allow a UE device to select a precoder with respect to two or more target TRPs and at least one victim TRP in a multi-TRP scenario.

[0008] 3GPP defines different types of SRS, including SRS for antenna switching (AS) for downlink CSI measurement based on uplink and downlink channel reciprocity. For example, the UE device uses different antenna ports to send a set of SRS signals for the AS. When the BS (e.g., gNB) receives the SRS signal, the BS estimates the uplink channel and uses the principle of reciprocity to derive the downlink channel estimate and determine the precoder for downlink transmission. The existing SRS for the AS is based on non-precoded operation, which means that the UE device sends the SRS for the AS without a precoder. The non-precoded SRS may generate interference to the victim TRP. According to various aspects of the present disclosure, the UE device uses a precoded SRS for the AS (rather than a non-precoded SRS for the AS) to increase the link budget toward the target TRP and reduce the interference at the victim TRP. The present disclosure provides a mechanism for maintaining an understanding between the BS and the UE device about the precoder for the SRS for the AS.

[0009] For example, the UE device receives a first CSI-RS from at least a first network entity (e.g., a first target TRP). The UE device also receives a second CSI-RS from a second network entity (e.g., a second target TRP). The UE device receives control signaling indicating at least one SRS resource set associated with the first CSI-RS or the second CSI-RS from the first network entity or the second network entity. The UE device sends one or more precoded SRS resources (e.g., NCB type SRS or AS type SRS) based on the received SRS resource set and the precoder calculated based on the first CSI-RS and the second CSI-RS. In some cases, the UE device determines a precoder based on the first CSI-RS and the second CSI-RS so that the precoded SRS resource suppresses interference with a signal received at a third network entity (e.g., a victim TRP). Details of the method (and related systems and techniques) are discussed in detail below. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The described embodiments and their advantages may be best understood by referring to the following description taken in conjunction with the accompanying drawings, which in no way limit any changes in form and detail that may be made to the described embodiments by one skilled in the art without departing from the spirit and scope of the described embodiments.

[0011] Figure 1 A diagram illustrating a wireless communication system including a plurality of network entities communicating over a plurality of cells according to some embodiments;

[0012] Figure 2 illustrates an example of wireless communication using multiple transmission and reception points (multiple TRPs) in accordance with some embodiments;

[0013] Figure 3 illustrates an example of wireless communication using multiple transmission and reception points (multiple TRPs) when interference occurs in accordance with some embodiments;

[0014] Figure 4 illustrates an example signaling diagram for precoder determination in an uplink transmission scheme according to some embodiments;

[0015] Figure 5A is a flow chart depicting a method for precoder determination by a user equipment (UE) device in a multi-TRP application according to some embodiments;

[0016] Figure 5B is a flow chart depicting a method for precoder determination by a UE device for interference suppression in a multi-TRP application according to some embodiments;

[0017] Fig. 6Ais a flow chart depicting a method for precoder determination by a network entity in a multi-TRP application according to some embodiments;

[0018] Figure 6B is a flow chart depicting a method for precoder determination by a network entity for interference suppression in a multi-TRP application according to some embodiments;

[0019] Fig. 7A illustrates an example signaling diagram for precoder determination in a non-codebook (NCB) semi-persistent uplink scheme with multiple TRPs according to some embodiments;

[0020] Figure 7B illustrates another example signaling diagram for precoder determination in a semi-persistent uplink scheme with multiple TRPs according to some embodiments;

[0021] Fig. 8A illustrates an example signaling diagram for precoder determination in an aperiodic uplink scheme utilizing multiple TRPs according to some embodiments;

[0022] Figure 8B illustrates another example signaling diagram for precoder determination in an aperiodic uplink scheme utilizing multiple TRPs according to some embodiments;

[0023] Fig. 9 illustrates an example signaling diagram for utilizing associated CSI-RS for precoder determination and sending uplink precoder reports according to some embodiments;

[0024] Fig.10 is a flow chart depicting a method for utilizing associated CSI-RS for precoder determination and sending uplink precoder reports by a UE device according to some embodiments;

[0025] Fig.11 is a flow chart depicting a method for precoder determination by a network entity utilizing associated CSI-RS and receiving an uplink precoder report according to some embodiments;

[0026] Fig.12 is a flow chart depicting a method for precoder determination by a UE device in a multi-TRP application according to some embodiments; and

[0027] Fig.13 is a flowchart depicting a method for precoder determination by a network entity in a multi-TRP application according to some embodiments. DETAILED DESCRIPTION

[0028] For ease of explanation, the following techniques are described in an example scenario in which one or more UE devices and a RAN implement one or more radio access technologies (RATs), including at least the fifth generation (5G) new radio (NR) standard (e.g., third generation partnership project (3GPP) release 15, 3GPP release 16, etc.) (hereinafter referred to as "5G NR" or "5G NR standard"). However, the present disclosure is not limited to networks configured with 5G NR RATs, but the techniques described herein can be applied to any combination of different ones adopted at the UE device and the RAN. In addition, the present disclosure is not limited to the examples and contexts described herein, but the techniques described herein can be applied to any network environment.

[0029] At a high level, the present disclosure provides methods and techniques for uplink precoder selection for multi-TRP applications including interference suppression. For example, the technology herein addresses uplink precoder determination, calculation, or selection with respect to two or more target TRPs. The uplink precoder also takes into account interference suppression in the victim TRP. In an uplink transmission scheme, the present disclosure further provides a mechanism for maintaining a common understanding between a network entity (e.g., a gNB) and a UE device regarding a precoder for an SRS used for antenna switching (AS). Therefore, the present disclosure achieves several technical advantages over existing uplink schemes. First, the UE device derives an uplink precoder based on more than one CSI-RS from two or more TRPs, which can improve the uplink performance of a UE with more than one target receive TRP. Second, the uplink precoder can use an interference suppression method to improve the performance of a neighboring cell or a victim TRP.

[0030] Figure 1A diagram 100 of a wireless communication system associated with a plurality of cells 190 is illustrated. The wireless communication system includes a user equipment (UE) 102 and a base station 104, some of which 104a include an aggregated base station architecture and other base stations 104b include a decomposed base station architecture. The aggregated base station architecture includes a radio unit (RU) 106, a distributed unit (DU) 108, and a centralized unit (CU) 110, which are configured to utilize a radio protocol stack physically or logically integrated within a single radio access network (RAN) node. The decomposed base station architecture utilizes a protocol stack physically or logically distributed between two or more units (e.g., RU 106, DU 108, CU 110). For example, CU 110 is implemented within a RAN node, and one or more DUs 108 may be co-located with CU 110, or alternatively, may be geographically or virtually distributed in one or more other RAN nodes. DU 108 may be implemented to communicate with one or more RUs 106. Each of the RU 106, DU 108, and CU 110 may be implemented as a virtual unit, such as a virtual radio unit (VRU), a virtual distributed unit (VDU), or a virtual central unit (VCU).

[0031] The operation and / or network design of the base station 104 can be based on the aggregated nature of the base station functions. For example, a decomposed base station architecture is utilized in an integrated access backhaul (IAB) network, an open radio access network (O-RAN) network, or a virtualized radio access network (vRAN), which may also be referred to as a cloud radio access network (C-RAN). Decomposition may include distributing functions between two or more units located at various physical locations, and virtually distributing the functions of at least one unit, which enables flexibility in network design. Various units of a decomposed base station architecture or a decomposed RAN architecture may be configured to communicate with at least one other unit in wired or wireless communication. For example, CU 110a communicates with DU108a-108b via corresponding midhaul links based on an F1 interface. DU 108a-108b may communicate with RU 106a and RU 106b-106c, respectively, via corresponding fronthaul links. RU 106a-106c can communicate with corresponding UE 102a-102c and 102s via one or more radio frequency (RF) access links based on Uu interface. In an example, multiple RU 106 and / or base station 104 can provide services for UE 102 at the same time, such as the access link of RU 106a of cell 190a and the UE 102a of cell 190e served by base station 104a of cell 190e at the same time.

[0032] One or more CUs 110, such as CU 110a or CU 110d, may communicate directly with the core network 120 via a backhaul link. For example, CU 110d communicates with the core network 120 via a backhaul link based on a next generation (NG) interface. One or more CUs 110 may also communicate indirectly with the core network 120 via one or more decomposed base station units, such as a near real-time RAN intelligent controller (RIC) 128 via an E2 link and a service management and orchestration (SMO) framework 116 that may be associated with a non-real-time RIC 118. The near real-time RIC 128 may communicate with the SMO framework 116 and / or the non-real-time RIC 118 via an A1 link. The SMO framework 116 and / or the non-real-time RIC 118 may also communicate with an open cloud (O-cloud) 130 via an O2 link. One or more CUs 110 may further communicate with each other via a backhaul link based on an Xn interface. For example, the CU 110d of the base station 104a communicates with the CU 110a of the base station 104b via a backhaul link based on an Xn interface. Similarly, the base station 104a of the cell 190e can communicate with the CU 110a of the base station 104b via a backhaul link based on an Xn interface.

[0033] RU 106, DU 108 and CU 110 and near real-time RIC 128, non-real-time RIC 118 and / or SMO framework 116 may include (or may be coupled to) one or more interfaces configured to send or receive information / signals via a wired or wireless transmission medium. Base station 104 or any one of the one or more decomposed base station units may be configured to communicate with one or more other base stations 104 or one or more other decomposed base station units via a wired or wireless transmission medium. In an example, a processor, memory and / or controller associated with executable instructions of the interface may be configured to provide communication between base station 104 and / or one or more decomposed base station units via a wired or wireless transmission medium. For example, a wired interface may be configured to send or receive information / signals via a wired transmission medium, such as a fronthaul link between RU 106d and baseband unit (BBU) 112 for cell 190d, or more specifically, a fronthaul link between RU 106d and DU 108d. The BBU 112 includes the DU 108d and the CU 110d, which may also have a wired interface configured between the DU 108d and the CU 110d to send or receive information / signals between the DU 108d and the CU 110d based on the midhaul link. In a further example, a wireless interface that may include a receiver, a transmitter, or a transceiver (such as an RF transceiver) may be configured to send or receive information / signals via a wireless transmission medium, such as information transmitted between the RU 106a of the cell 190a and the base station 104a of the cell 190e via the cross-cell communication beam of the RU 106a and the base station 104a.

[0034] One or more high-level control functions (such as functions related to radio resource control (RRC), packet data convergence protocol (PDCP), service data adaptation protocol (SDAP), etc.) can be hosted at CU 110. Each control function can be associated with an interface for transmitting signals based on one or more other control functions hosted at CU 110. User plane functions (such as central unit-user plane (CU-UP) functions), control plane functions (such as central unit-control plane (CU-CP) functions), or a combination thereof can be implemented based on CU 110. For example, CU 110 may include one or more CU-UP processes and / or one or more CU-CP processes. When implemented in an O-RAN configuration, the CU-UP function can be based on bidirectional communication with the CU-CP function via an interface (such as an E1 interface (not shown)).

[0035] The CU 110 may communicate with the DU 108 for network control and signal transmission. The DU 108 is a logical unit of the base station 104 that is configured to perform one or more base station functions. For example, the DU 108 may control the operation of one or more RUs 106. One or more of the following may be hosted at the DU 108: a radio link control (RLC) layer, a media access control (MAC) layer, or one or more higher physical (PHY) layers, such as forward error correction (FEC) modules for encoding / decoding, scrambling, modulation / demodulation, etc. The DU 108 may host such functions based on the functional division of the DU 108. The DU 108 may similarly host one or more lower PHY layers, where each lower layer or module may be implemented based on an interface for communicating with other layers and modules hosted at the DU 108, or based on a control function hosted at the CU 110.

[0036] The RU 106 may be configured to implement lower layer functions. For example, the RU 106 is controlled by the DU 108 and may correspond to a logical node hosting RF processing functions or lower layer PHY functions, such as performing fast Fourier transform (FFT), inverse FFT (iFFT), digital beamforming, physical random access channel (PRACH) extraction and filtering, etc. The functions of the RU 106 may be based on functional partitioning, such as lower layer functional partitioning.

[0037] The RU 106 may send or receive over-the-air (OTA) communications with one or more UEs 102. For example, the RU 106b of the cell 190b communicates with the UE 102b of the cell 190b via the first communication beam set 132 of the RU 106b and the second communication beam set 134 of the UE 102b, which may correspond to inter-cell communication beams or cross-cell communication beams. Both real-time and non-real-time features of the control plane and user plane communications of the RU 106 may be controlled by the associated DU 108. Thus, the DU 108 and the CU 110 may be used in a cloud-based RAN architecture (such as a vRAN architecture), and the SMO framework 116 may be used to support non-virtualized and virtualized RAN network elements. For non-virtualized network elements, the SMO framework 116 may support the deployment of dedicated physical resources for RAN coverage, where the dedicated physical resources may be managed through an operation and maintenance interface (such as an O1 interface). For virtualized network elements, the SMO framework 116 can interact with a cloud computing platform (such as O-cloud 130) via an O2 link (e.g., a cloud computing platform interface) to manage the network elements. The virtualized network elements may include, but are not limited to, RU 106, DU 108, CU 110, near real-time RIC 128, etc.

[0038] The SMO framework 116 may be configured to communicate directly with one or more RUs 106 using an O1 link. The non-real-time RIC 118 of the SMO framework 116 may also be configured to support the functionality of the SMO framework 116. For example, the non-real-time RIC 118 implements logic functions that are capable of controlling non-real-time RAN features and resources, features / applications of the near real-time RIC 128, and / or artificial intelligence / machine learning (AI / ML) processes. The non-real-time RIC 118 may communicate (or couple) with the near real-time RIC 128, such as through an A1 interface. The near real-time RIC 128 may implement logic functions that are capable of controlling near real-time RAN features and resources based on data collection and interaction through an E2 interface (such as an E2 interface between the near real-time RIC 128 and the CU 110a and the DU 108b).

[0039] The non-real-time RIC 118 may receive parameters or other information from an external server to generate an AI / ML model for deployment in the near-real-time RIC 128. For example, the non-real-time RIC 118 receives parameters or other information from the O-cloud 130 via the O2 link to deploy the AI / ML model to the real-time RIC 128 via the A1 link. The near-real-time RIC 128 may utilize the parameters and / or other information received from the non-real-time RIC 118 or the SMO framework 116 via the A1 link to perform near-real-time functions. The near-real-time RIC 128 and the non-real-time RIC 115 may be configured to adjust the performance of the RAN. For example, the non-real-time RIC 116 monitors patterns and long-term trends to improve the performance of the RAN. The non-real-time RIC 116 may also deploy the AI / ML model through the SMO framework 116 for implementing corrective actions, such as initiating reconfiguration of the O1 link or instructing the management process of the A1 link.

[0040] Any combination of RU 106, DU 108, and CU 110 or any reference thereto individually may correspond to base station 104. Therefore, base station 104 may include at least one of RU 106, DU 108, or CU 110. Base station 104 provides UE 102 with access to core network 120. That is, base station 104 may relay communications between UE 102 and core network 120. Base station 104 may be associated with a macro cell of a high-power cellular base station and / or a small cell of a low-power cellular base station. For example, cell 190e corresponds to a macro cell, and cells 190a-190d may correspond to a small cell. Small cells include femto cells, pico cells, micro cells, etc. A cell structure including at least one macro cell and at least one small cell may be referred to as a "heterogeneous network."

[0041] Transmissions from the UE 102 to the base station 104 / RU 106 are referred to as uplink (UL) transmissions, while transmissions from the base station 104 / RU 106 to the UE 102 are referred to as downlink (DL) transmissions. Uplink transmissions may also be referred to as reverse link transmissions, while downlink transmissions may also be referred to as forward link transmissions. For example, the RU 106 d utilizes the antenna of the base station 104 a of the cell 190 d to send downlink / forward link communications to the UE 102 d, or receive uplink / reverse link communications from the UE 102 d, based on the Uu interface associated with the access link between the UE 102 d and the base station 104 a / RU 106 d.

[0042] The communication link between UE 102 and base station 104 / RU 106 can be based on multiple input multiple output (MIMO) antenna technology, including spatial multiplexing, beamforming and / or transmit diversity. The communication link can be associated with one or more carriers. UE 102 and base station 104 / RU 106 can utilize Y MHz (e.g., 5 MHz, 10 MHz, 15 MHz, 20 MHz, 100 MHz, 400 MHz, etc.) spectrum bandwidth allocated per carrier in up to a total of Yx MHz carrier aggregation, where x component carriers (CCs) are used for communication in each of the uplink and downlink directions. The carriers may be adjacent to each other along the spectrum, or may not be adjacent to each other. In an example, uplink carriers and downlink carriers may be allocated in an asymmetric manner, and more or fewer carriers may be allocated for uplink or downlink. A component carrier may include a primary component carrier and one or more secondary component carriers. The primary component carrier may be associated with a primary cell (PCell), and the secondary component carrier may be associated with a secondary cell (SCell).

[0043] Some UEs 102 (such as UEs 102a and 102s) may perform device-to-device (D2D) communications via a sidelink. For example, a sidelink communication / D2D link utilizes a spectrum of a wireless wide area network (WWAN) associated with uplink and downlink communications. The sidelink communication / D2D link may also use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH), a physical sidelink discovery channel (PSDCH), a physical sidelink shared channel (PSSCH), and / or a physical sidelink control channel (PSCCH) to transmit information between UEs 102a and 102s. Such sidelink / D2D communications may be performed via various wireless communication systems, such as wireless fidelity (Wi-Fi) systems, Bluetooth systems, long term evolution (LTE) systems, new radio (NR) systems, and the like.

[0044] The electromagnetic spectrum is often subdivided into different categories, bands, channels, etc. based on different frequencies / wavelengths associated with the electromagnetic spectrum. Fifth Generation (5G) NR is often associated with two operating bands, referred to as Frequency Range 1 (FR1) and Frequency Range 2 (FR2). FR1 ranges from 410 MHz—7.125 GHz, and FR2 ranges from 24.25 GHz—52.6 GHz. FR1 is often referred to as the “sub-6 GHz” band, although a portion of FR1 is actually greater than 6 GHz. In contrast, FR2 is often referred to as the “millimeter wave” (mmW) band. FR2 is not the same as the “extremely high frequency” (EHF) band, but is an approximate subset of that band, the EHF band ranges from 30 GHz – 300 GHz, and is sometimes also referred to as the “millimeter wave” band. The frequencies between FR1 and FR2 are often referred to as the “mid-band” frequencies. The operating band of mid-band frequencies may be referred to as frequency range 3 (FR3), which ranges from 7.125 GHz to 24.25 GHz. The frequency bands within FR3 may include characteristics of FR1 and / or FR2. Therefore, the characteristics of FR1 and / or FR2 may be extended to mid-band frequencies. Higher operating bands have been identified to extend 5G NR communications above 52.6 GHz associated with the upper limit of FR2. Three of these higher operating bands include FR2-2 (ranging from 52.6 GHz – 71 GHz), FR4 (ranging from 71 GHz – 114.25 GHz), and FR5 (ranging from 114.25 GHz – 300 GHz). The upper limit of FR5 corresponds to the upper limit of the EHF band. Therefore, unless otherwise expressly stated herein, the term “below 6 GHz” may refer to frequencies less than 6 GHz, frequencies within FR1, or frequencies that may include mid-band frequencies. Further, unless otherwise expressly stated herein, the term "millimeter wave" or mmW refers to frequencies that may include mid-band frequencies, frequencies that may be within FR2, FR4, FR2-2 and / or FR5, or frequencies that may be within the EHF band.

[0045] UE 102 and base station 104 / RU 106 may each include multiple antennas. Multiple antennas may correspond to antenna elements, antenna panels, and / or antenna arrays that may facilitate beamforming operations. For example, RU 106b transmits a downlink beamformed signal to UE 102b based on a first beam set 132 in one or more transmit directions of RU 106b. UE 102b may receive a downlink beamformed signal from RU 106b based on a second beam set 134 in one or more receive directions of UE 102b. In a further example, UE 102b may also transmit an uplink beamformed signal to RU 106b based on a second beam set 134 in one or more transmit directions of UE 102b. RU 106b may receive an uplink beamformed signal from UE 102b in one or more receive directions of RU 106b. UE 102b may perform beam training to determine the optimal receive and transmit directions for the beamformed signal. The transmit and receive directions of the UE 102 and the base station 104 / RU 106 may be the same, or may be different. In a further example, a beamformed signal may be transmitted between the first base station 104a and the second base station 104b. For example, the RU 106a of the cell 190a may send a beamformed signal to the base station 104a of the cell 190e based on the RU beam set 136 in one or more transmit directions of the RU 106a. The base station 104a of the cell 190e may receive a beamformed signal from the RU 106a based on the base station beam set 138 in one or more receive directions of the base station 104a. Similarly, the base station 104a of the cell 190e may send a beamformed signal to the RU 106a based on the base station beam set 138 in one or more transmit directions of the base station 104a. The RU 106a may receive a beamformed signal from the base station 104a of the cell 190e based on the RU beam set 136 in one or more receive directions of the RU 106a.

[0046] The base station 104 may include and / or be referred to as a next generation evolved Node B (ng-eNB), a generation NB (gNB), an evolved NB (eNB), an access point, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS), an extended service set (ESS), a transmit receive point (TRP), a network node, a network entity, a network device, or other related terms. The base station 104 or an entity at the base station 104 may be implemented as an IAB node, a relay node, a side link node, a converged (integrated) base station having a RU 106 and a BBU including a DU 108 and a CU 110, or as a decomposed base station 104b including one or more of the RU 106, the DU 108, and / or the CU 110. The set of converged or decomposed base stations 104a-104b may be referred to as a next generation radio access network (NG-RAN).

[0047] The core network 120 may include an access and mobility management function (AMF) 121, a session management function (SMF) 122, a user plane function (UPF) 123, a unified data management (UDM) 124, a gateway mobile location center (GMLC) 125, and / or a location management function (LMF) 126. The core network 120 may also include one or more location servers (which may include the GMLC 125 and the LMF 126), as well as other functional entities. For example, the one or more location servers include one or more location / positioning servers, and in addition to one or more of a positioning determination entity (PDE), a serving mobile location center (SMLC), a mobile positioning center (MPC), etc., the one or more location / positioning servers may also include the GMLC 125 and the LMF 126.

[0048] AMF 121 is a control node that handles signal transmission between UE 102 and core network 120. AMF 121 supports registration management, connection management, mobility management, and other functions. SMF 122 supports session management and other functions. UPF 123 supports packet routing, packet forwarding, and other functions. UDM 124 supports the generation of authentication and key agreement (AKA) credentials, user identity handling, access authorization, and subscription management. GMLC 125 provides an interface for clients / applications (e.g., emergency services) to access UE positioning information. LMF 126 receives measurement and assistance information from NG-RAN and UE 102 via AMF 121 to calculate the positioning of UE 102. NG-RAN can use one or more positioning methods to determine the location of UE 102. Positioning UE 102 can involve signal measurement, positioning estimation, and optional speed calculation based on measurement. Signal measurement can be performed by UE 102 and / or serving base station 104 / RU 106.

[0049] The transmitted signal may also be based on one or more of a satellite positioning system (SPS) 114, such as a signal measured for positioning. In an example, the SPS 114 of the cell 190c may communicate with one or more UEs 102 (such as UE 102c) and one or more base stations 104 / RU 106 (such as RU 106c). The SPS 114 may correspond to one or more of a global navigation satellite system (GNSS), a global positioning system (GPS), a non-terrestrial network (NTN), or other satellite positioning / position systems. The SPS 114 may be associated with LTE signals, NR signals (e.g., based on round trip time (RTT) and / or multiple RTT), wireless local area network (WLAN) signals, terrestrial beacon systems (TBS), sensor-based information, NR enhanced cell ID (NR E-CID) technology, downlink departure angle (DL-AoD), downlink arrival time difference (DL-TDOA), uplink arrival time difference (UL-TDOA), uplink arrival angle (UL-AoA), and / or other systems, signals, or sensors.

[0050] UE 102 may be configured as a cellular phone, a smart phone, a Session Initiation Protocol (SIP) phone, a laptop computer, a personal digital assistant (PDA), a satellite radio, a GPS, a multimedia device, a video device, a digital audio player (e.g., a Moving Picture Experts Group (MPEG) Audio Layer 3 (MP3) player), a camera, a game console, a tablet computer, a smart device, a wearable device, a vehicle, a utility meter, a gas pump, a home appliance, a healthcare device, a sensor / actuator, a display, or any other device with similar functionality. Some of UE 102 may be referred to as Internet of Things (IoT) devices, such as parking meters, gas pumps, home appliances, vehicles, healthcare equipment, etc. UE 102 may also be referred to as a station (STA), a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communication device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handheld device, a mobile client, a client, or other similar terms. The term UE may also apply to a roadside unit (RSU), which may communicate with other RSU UEs, non-RSU UEs, the base station 104, and / or entities at the base station 104, such as the RU 106.

[0051] Still refer to Figure 1In certain aspects, the UE 102 may include a sounding reference signal (SRS) precoding component 140 configured to transmit one or more precoded SRS resources in at least one SRS resource set indicated by control signaling from the base station 104 using a precoder calculated based on two or more CSI-RS from two or more corresponding target TRPs. As described below Figure 2 As further discussed, the UE 102 can use the SRS precoding component 140 to determine a precoder for sending one or more precoded SRS resources based on two or more CSI-RS and at least one other CSI-RS from a victim TRP, such that the precoded SRS resources suppress interference to a signal received at a third network entity.

[0052] In some cases, the SRS precoding component 140 may include one or more radio frequency (RF) modems, a processor, and at least one non-transitory memory storing executable instructions for causing the processor and / or the one or more RF modems to perform one or more functions or operations disclosed herein (described in detail below). For example, the SRS precoding component 140 is configured to receive one or more CSI-RS from a network entity and send one or more CSI reports to the network entity.

[0053] In certain aspects, the base station 104 or a network entity of the base station 104 may include a precoded SRS processing component 150 configured to send control signaling indicating at least one SRS resource set to the UE device 102. The precoded SRS processing component 150 then sends a CSI-RS associated with the at least one SRS resource set. The precoded SRS processing component 150 receives one or more precoded SRS resources in the at least one SRS resource set.

[0054] In some cases, the network-side precoded SRS processing component 150 may include one or more RF modems, a processor, and at least one non-transitory memory storing executable instructions for causing the processor and / or one or more RF modems to perform one or more functions or operations disclosed herein. For example, the precoded SRS processing component 150 is configured to receive one or more precoded SRS resources precoded based on a CSI-RS transmitted by a network entity and at least a second CSI-RS transmitted by a second network entity (e.g., another target TRP associated with the base station 104).

[0055] Figure 2An example 200 of wireless communication using multiple TRPs 106a-106d according to some embodiments is illustrated. In such a multiple TRP scenario, the UE device 102 can communicate with more than one TRP simultaneously to take advantage of throughput and reliability. Although the multiple TRPs 106a-106d are labeled as "106", they can communicate with Figure 1 The example RU 106 is different, depending on the specific deployment and / or network configuration as understood in the 5G NR multi-TRP scenario. Although multiple TRPs 106a-106d are available, the path loss between the UE device 102 and each of the TRPs 106 is different. During operation, the UE may need to send some uplink signals to each TRP. In one example, for multi-TRP operation based on downlink coherent joint transmission, the base station 104 (e.g., gNB) triggers the UE to send a sounding reference signal (SRS) for antenna switching (AS) to each TRP to perform downlink channel state information (CSI) measurements based on uplink / downlink channel reciprocity. In another example, the base station 104 can trigger the UE device 102 to send a physical uplink shared channel (PUSCH) or a physical uplink control channel (PUCCH) to one or more TRPs. The UE can send PUSCH or PUCCH based on a single beam or different beams, such as when the UE enables analog beamforming. One or more TRPs can then perform independent or joint decoding of PUSCH / PUCCH. This operation can improve the reliability of uplink transmission.

[0056] The 3GPP standard includes different uses of SRS, including SRS for codebook (CB) based transmission (SRS for CB), SRS for non-codebook (NCB) based transmission (SRS for NCB), SRS for beam management (BM), and SRS for antenna switching (AS). The gNB can configure the use of SRS resource sets through the RRC parameter usage. Various aspects of the present disclosure are related to NCB and AS types in the examples of this article, while the precoder determination for interference suppression is not limited to a specific SRS type.

[0057] The SRS for CB is used for uplink channel state information (CSI) measurement for uplink CB-based transmissions. The UE sends the SRS for CB from one or more antenna ports. The gNB measures the uplink channel based on the SRS for CB and selects a precoder from a predefined codebook. Typically, the selected precoder may be a precoder that is capable of producing the strongest precoded channel energy based on the estimated channel. The gNB may then indicate the precoder to the UE through the downlink control information (DCI) field precoding information and the number of layers, where the transmit precoder matrix indicator (TPMI) and transmit rank indicator (TRI) are indicated. The UE may then identify the precoder for PUSCH transmission based on the predefined precoder indicated by the TPMI and TRI.

[0058] The SRS for NCB is used for uplink CSI measurements for transmissions based on the uplink NCB. For the SRS resource set for NCB, the gNB may configure the associated CSI reference signal (CSI-RS) through RRC signaling. The UE may estimate the downlink channel based on the associated CSI-RS and use the estimated downlink channel to derive the uplink precoder for the SRS assuming reciprocity of the uplink and downlink channels. In one example, the uplink precoder may be calculated based on the eigenvector of the average estimated channel as follows:

[0059] Where the matrix V is the calculated precoder; is the estimated channel at subcarrier j based on the associated CSI-RS, and its dimension is Multiply ,in is the number of receive antenna ports and is the number of antenna ports associated with CSI-RS; N is the total number of subcarriers associated with CSI-RS.

[0060] The UE may then apply a rank-one precoder (e.g., one column of the matrix V) to the SRS resources for the NCB. Thus, each SRS resource for the NCB is transmitted from one port with a rank-1 precoder. After measurement of the SRS resources in the resource set for the NCB, the gNB may indicate K SRS resource indicators (SRIs) for uplink NCB transmissions for rank-K transmissions, where K is an integer greater than 0. The UE shall send the PUSCH based on the precoder applied to the most recently transmitted of the indicated K SRS resources.

[0061] The SRS for BM is used for uplink beam measurement and selection. The UE can apply different beams to different SRS resources for BM. The gNB performs measurements on the SRS resources. Then, based on the measurements on the SRS resources for BM, the gNB can perform uplink beam selection by indicating an SRI for an uplink channel (e.g., PUSCH, PUCCH, or another SRS) to the UE. The UE sends the corresponding uplink channel based on the same beam as the beam applied to the SRS indicated by the SRI.

[0062] The SRS for AS is used for downlink CSI measurement based on uplink and downlink channel reciprocity. The UE can send SRS resource sets for AS using different antenna ports. Then, by receiving the SRS resources, the gNB can estimate the uplink channel in order to derive the downlink channel and determine the precoder for downlink transmission. In one example, for a UE with X (e.g., X=2) transmit antenna ports and Y (e.g., Y=4) receive antenna ports (xTyR), the gNB can configure an SRS resource set with ceil(y / x) (e.g., 2) SRS resources, where each SRS resource is sent from X antenna ports.

[0063] The UE sends SRS resources in a periodic SRS resource set based on the periodicity and offset configured by the RRC parameter periodityAndOffset-p. After receiving the activation signaling of the MAC control element (CE), the UE sends SRS resources in a semi-persistent SRS resource set based on the periodicity and offset configured by the RRC parameter periodityAndOffset-sp. After receiving a DCI to trigger an SRS resource set in a time slot with a time slot offset configured by the RRC parameter slotOffset from the time slot with the last symbol of the DCI or a reference time slot indicated by the DCI, the UE sends SRS resources in an aperiodic SRS resource set. The triggered SRS resource set index is indicated by the DCI field SRS request. DCI can also be used to trigger PDSCH / PUCCH or PUSCH.

[0064] Figure 3An example 300 of wireless communication using multiple transmission and reception points (multiple TRPs) when interference occurs according to some embodiments is illustrated. As shown, the UE device 102 intends to provide uplink transmissions to target TRPs 3 and 4, as indicated by the solid lines. The UE device 102 selects a precoder that is sufficient for target TRP 4 but insufficient for target TRP 3 based on a conventional precoder determination using only the CSI-RS from TRP 4. In addition, as mentioned above, due to the path loss difference, the precoder may cause a signal that generates strong interference (as indicated by the dashed line) to the victim TRPs 1 and 2. For example, the UE device 102 does not consider the signals received at the victim TRPs 1 and 2, and selects a precoder that causes interference.

[0065] Conventionally, when determining the uplink precoder for uplink NCB transmission, the UE device 102 may rely only on the downlink channel from one TRP, such as one CSI-RS from one TRP. However, when the number of target TRPs is more than one, the UE faces difficulty in selecting a precoder to produce a good precoded channel energy. Further, in multi-TRP operation, the uplink signal may generate strong interference to some adjacent TRPs because the path loss between the UE and the TRP may be small. In the current case of NCB-based transmission operation, the precoder selection does not take into account the interference level. However, it is possible that the selected precoder may generate more interference to adjacent TRPs. Therefore, if Figure 3 As shown, how to select the uplink precoder for uplink NCB-based transmission may be a problem with respect to more than one target reception TRP and with respect to interference suppression for some adjacent TRPs.

[0066] In addition, the conventional SRS for antenna switching (AS) is based on non-precoded operation. Therefore, in the conventional scheme, the UE sends the SRS for AS without a precoder. Although the link budget for the non-precoded SRS may be smaller than the precoded SRS, the non-precoded SRS may generate more interference to the adjacent TRP than the precoded SRS. According to various aspects of the present disclosure, the UE device uses the precoded SRS for AS to increase the link budget and reduce interference. For the precoded SRS for AS, the technology of this article solves how to derive, calculate, determine or select a precoder for the AS type SRS. Accordingly, the gNB also needs to know the uplink precoder in order to recover the downlink channel, as follows. in indicates the estimated downlink channel at subcarrier j, is the estimated channel from the SRS for AS at subcarrier j; W is the precoder applied to the SRS for AS.

[0067] Aspects of the present disclosure also address how to maintain the same understanding between the gNB and the UE regarding the selected precoder (e.g., precoder reporting) for SRS used for the AS.

[0068] Figure 4 An example signaling diagram for making precoder determination in an uplink transmission scheme according to some embodiments is illustrated. Signaling diagram 400 illustrates a process for uplink precoder selection with respect to two or more target receive TRPs and interference suppression. As shown, a UE device 102 may send 420 a UE capability report regarding uplink precoder selection for SRS with more than one associated CSI-RS (e.g., in a multiple TRP use case). A network entity 410 (e.g., its TRP, such as a first target TRP), upon receiving the UE capability report, sends 430 control signaling to configure more than one semi-persistent CSI-RS for at least one semi-persistent SRS resource set in the UE device 102.

[0069] In some cases, the network entity 410 sends 440 control signaling to trigger an SRS resource set associated with more than one CSI-RS and the associated CSI-RS. The network entity 410 then sends 450 a plurality of CSI-RS-1s associated with the triggered SRSs via a first TRP. The network entity 410 also sends 455 a plurality of CSI-RS-2s associated with the triggered SRSs via a second TRP. Although Figure 4 The network entity 410 is illustrated as sending CSI-RS-1 and CSI-RS-2 separately, but the network entity 410 may send CSI-RS jointly, simultaneously, or concurrently. In some cases, the network entity 410 may include multiple TRPs for sending (450 and 455, 459) CSI-RS, or when the other network entity and the network entity 410 are transparent to each other, another network entity (not shown) or TRP may send 455 CSI-RS-2. The UE device 102 determines 460 a precoder for an SRS resource in an SRS resource set for activation based on the received CSI-RS when measuring the CSI-RS from the network entity 410 (or network entity). Then, the UE device 102 sends 470 the triggered SRS to the network entity 410 using the determined precoder. The network entity 410 receives 480 the triggered SRS.

[0070] In some embodiments, the UE reports one or more capabilities of uplink precoder selection with interference suppression to the network entity 410. For example, the one or more capabilities indicate a maximum number of associated CSI-RS resources for signal reception for uplink precoder selection and a maximum number of associated CSI-RS resources for interference suppression for uplink precoder selection. In other implementations, the network entity 410 receives the one or more capabilities from a core network (e.g., an access and mobility management function (AMF)).

[0071] In some embodiments, the network entity 410 receives one or more UE capabilities regarding uplink precoder selection for SRS from another base station (e.g., a gNB or an eNB). Based on the one or more UE capabilities, the network entity 410 may configure at least one SRS resource set having two or more associated CSI-RS resources. In some embodiments, the network entity 410 sends an RRC message (e.g., an RRCReconfiguration message) including associated CSI-RS related information to the UE. Then, for semi-persistent SRS, the network entity 410 may send a MAC CE to the UE to trigger transmission; for aperiodic SRS, the network entity 410 may send a DCI to the UE to trigger transmission. The network entity 410 may activate or trigger the associated CSI-RS based on a separate MAC CE or DCI or the same MAC CE or DCI used to trigger semi-persistent SRS or aperiodic SRS transmission. The network entity 410 sends the associated CSI-RS for the UE to derive the uplink precoder for SRS. Based on the received CSI-RS, the UE can estimate the channel for the target reception TRP and / or the channel for the victim TRP to determine the uplink precoder for signal reception and interference suppression. The UE can then send 470 the triggered SRS based on the determined uplink precoder.

[0072] Details for each step are provided in the embodiments below. The UE may apply the selected precoder to uplink signal transmission. Precoder selection for signal reception is to identify the uplink precoder to enhance the received power from the uplink signal at the target receive TRP using the selected precoder. Precoder selection for interference suppression is to identify the uplink precoder to reduce the interference of the uplink signal to the neighboring / victim TRP using the selected precoder.

[0073] Figure 5A5 is a flowchart depicting a method for precoder determination by a user equipment (UE) device in a multi-TRP application according to some embodiments. Method 500 illustrates an example behavior of a UE device 102 for selecting an uplink precoder for an SRS using an associated CSI-RS list. The UE device may use an associated CSI-RS list to select an uplink precoder for uplink signal reception. As shown, the UE device (optionally) sends 520 a UE capability report on uplink precoder selection for SRS using more than one associated CSI-RS. The UE device receives 530 control signaling for configuring an associated CSI-RS list for at least one SRS resource set. The UE device may receive 540 a media access control (MAC) control element (CE) for activating a semi-persistent CSI-RS, or may receive 540 downlink control information (DCI) for triggering an aperiodic SRS and associated aperiodic CSI-RS.

[0074] The UE device receives 532 an associated CSI-RS list (for at least one resource set). Based on the received CSI-RS list, the UE device determines 560 a precoder for an SRS resource in the resource set based on the received associated CSI-RS list. The associated CSI-RS list is used for precoder selection for signal reception. The UE device then sends 570 an SRS based on the determined precoder.

[0075] Figure 5B 5 is a flow chart depicting a method for precoder determination by a UE device for interference suppression in a multi-TRP application in accordance with some embodiments. As shown, method 502 illustrates UE behavior for selecting an uplink precoder for SRS using two associated CSI-RS lists. The first associated CSI-RS list is used by the UE to select an uplink precoder for uplink signal reception, and the second associated CSI-RS list is used to select a precoder for uplink interference suppression. Figure 5A In contrast, operations 520, 540, and 570 are common. On the other hand, the UE device receives 532 control signaling for configuring a first associated CSI-RS list for signal reception and a second associated CSI-RS list for interference suppression for at least one SRS resource set. The UE device receives 559 the first associated CSI-RS list and the second associated CSI-RS list, and determines 560 a precoder for the SRS resources in the resource set based on the two received associated CSI-RS lists. The first associated CSI-RS list is used for precoder selection for signal reception. The second associated CSI-RS list is used for precoder selection for interference suppression.

[0076] Fig. 6A is a flow chart depicting a method for precoder determination by a network entity in a multi-TRP application according to some embodiments. The method 600 performed by the network entity may correspond to the method 500 performed by the UE device. That is, the method 600 illustrates gNB behavior for selecting an uplink precoder for SRS using one associated CSI-RS list. As shown, the network entity receives 620 a UE capability report regarding uplink precoder selection for SRS using more than one associated CSI-RS. The network entity sends 630 control signaling to configure an associated CSI-RS list for at least one SRS resource set. The network entity sends 640 a MAC CE to activate a semi-persistent SRS and an associated semi-persistent CSI-RS; or the network entity sends 640 a DCI to trigger an aperiodic SRS and an associated aperiodic CSI-RS. The network entity then sends 659 the associated CSI-RS list to the UE device. The network entity receives 670 the triggered SRS precoded by the UE device.

[0077] Figure 6B is a flow chart depicting a method for precoder determination by a network entity for interference suppression in a multi-TRP application according to some embodiments. The method 602 performed by the network entity may correspond to the method 502 performed by the UE device. That is, the method 602 illustrates gNB behavior for selecting an uplink precoder for SRS using two associated CSI-RS lists (one for interference suppression): a first associated CSI-RS list is used by the UE to select an uplink precoder for uplink signal reception, and a second associated CSI-RS list is used by the UE to select an uplink precoder for uplink interference suppression. Fig. 6A In contrast, operations 620, 640, and 670 are common. On the other hand, the network entity sends 632 control signaling to configure a first associated CSI-RS list for signal reception and a second associated CSI-RS list for interference suppression for at least one SRS resource set. The network entity also sends 659 the first associated CSI-RS list and the second associated CSI-RS list to the UE device (e.g., via different TRPs, such as a target TRP and a victim TRP).

[0078] In various aspects of the present disclosure, unless otherwise specified, RRC signaling may include / indicate an RRC reconfiguration message from the gNB to the UE, or a system information block (SIB). The SIB may be an existing SIB (e.g., SIB1) or a new SIB (e.g., SIB J, where J is an integer greater than 21) sent by the gNB.

[0079] In some embodiments, the UE reports to the network entity 410 a capability indicating that the UE is capable of uplink precoder selection and / or interference suppression for two or more target receive TRPs. The UE capability may include at least one of the following: a maximum number of associated CSI-RS resources for signal reception for an SRS resource set for NCB, a maximum number of associated CSI-RS resources for interference suppression for an SRS resource set for NCB; whether the UE supports associated CSI-RS resources for an SRS resource set for AS; or a maximum number of associated CSI-RS resources for signal reception for an SRS resource set for AS; a maximum number of associated CSI-RS resources for interference suppression for an SRS resource set for AS. The maximum number of associated CSI-RS resources in the above UE capability may be counted / determined based on the maximum number of associated CSI-RS resources configured and / or the maximum number of associated CSI-RS resources in a time slot. The UE capability may be reported by feature set, by frequency band, by frequency band combination, and / or by UE.

[0080] In some embodiments, the network entity 410 may send control signaling on the associated CSI-RS resources for the SRS resource set for NCB / AS through higher layer signaling (e.g., RRC signaling). In some embodiments, with respect to two or more target reception TRPs, the network entity 410 may configure additional associated CSI-RS resources or associated CSI-RS resource lists for signal reception for the SRS for NCB / AS through RRC signaling. In one example, the network entity 410 may configure the associated CSI-RS resources through the following RRC parameter channelMeasAssociatedCSI-RSList, as shown in the example ASN.1 code 1 below.

[0081] In some embodiments, with respect to two or more target reception TRPs, the network entity 410 configures one or more associated CSI-RS resource lists for signal reception for the SRS used for NCB / AS through RRC signaling (e.g., the channelMeasAssociatedCSI-RSList field in the aperiodic field, the semi-persistent field, and / or the periodic field), and down-selects at least one associated CSI-RS resource through MAC CE or DCI.

[0082] In one example, for a semi-persistent SRS, the network entity 410 may select an associated CSI-RS resource index from the associated CSI-RS resource list configured for signal reception (e.g., channelMeasAssociatedCSI-RSList in the semi-persistent field), and include the selected index in the MAC CE field (e.g., the associated CSI-RS resource index of the MAC CE). In one implementation, the size of the MAC CE field may be determined by the UE and the network entity 410 as bits, where C is the number of associated CSI-RS resources configured by RRC for signal reception.

[0083] In some embodiments, the size of the MAC CE field is a fixed number of bits. In one example, the fixed number is the maximum number of associated CSI-RS resources (e.g., maxNrofSRS-SignalReception). In another example, the fixed number is ceil(log2C), where C is the maximum number of associated CSI-RS resources for signal reception. In another example, for semi-persistent SRS, the network entity 410 may select one or more associated CSI-RS resource indexes via a MAC CE field (e.g., an associated CSI-RS resource index of a MAC CE), where the MAC CE field may be a bitmap and each bit indicates whether a specific CSI-RS is selected. In one implementation, the size of the MAC CE is a fixed number of bits. For example, the fixed number is equal to or greater than the maximum number of associated CSI-RS resources (e.g., maxNrofSRS-SignalReception).

[0084] In one example, for an aperiodic SRS, the network entity 410 may select an associated CSI-RS resource index from an associated CSI-RS resource list (e.g., channelMeasAssociatedCSI-RSList in the aperiodic field) through a DCI field (e.g., an associated CSI-RS resource index of the DCI). The bit width of the DCI field may be , where C is the number of candidate associated CSI-RS resources configured by RRC. In another example, for aperiodic SRS, the network entity 410 may select one or more associated CSI-RS resource indexes through a DCI field (e.g., associated CSI-RS resource index), where the DCI field may be a bitmap and each bit indicates whether a CSI-RS is selected.

[0085] In some embodiments, regarding interference suppression, the network entity 410 may configure additional associated CSI-RS resources for interference suppression for the SRS used for NCB / AS. In one example, the network entity 410 may configure associated CSI-RS resources for interference suppression via the following RRC parameter interfereMeasAssociatedCSI-RS, as shown in the example ASN.1 code 2 below.

[0086] In one example, the network entity 410 may configure an associated CSI-RS resource list for interference mitigation via the following RRC parameter interfereMeasAssociatedCSI-RSList, as shown in example ASN.1 code 3 below.

[0087] In some embodiments, the network entity 410 may configure a first associated CSI-RS resource list for signal reception and a second associated CSI-RS resource list for RRC interference suppression. In one example, the network entity 410 may configure the first associated CSI-RS resource list through an RRC parameter channelMeasAssociatedCSI-RSList and configure the second associated CSI-RS resource list through an RRC parameter interferingMeasAssociatedCSI-RSList, as shown in the example ASN.1 code 4 below.

[0088] In some embodiments, with respect to two or more victim TRPs for interference suppression, the network entity 410 may configure an associated CSI-RS resource list for interference suppression for the SRS used for NCB / AS through RRC signaling (e.g., the interferenceMeasAssociatedCSI-RSList field in the non-periodic field, the semi-persistent field, and / or the periodic field), and down-select at least one associated CSI-RS resource through MAC CE or DCI.

[0089] In one example, for the semi-persistent SRS, the network entity 410 may select an associated CSI-RS resource index from a configured candidate associated CSI-RS resource list for interference suppression (e.g., interferenceMeasAssociatedCSI-RSList in the semi-persistent field) through the MAC CE field (e.g., the associated CSI-RS resource index of the MACCE). In one implementation, the size of the MAC CE field may be determined by the UE and the network entity 410 as bits, where C is the number of associated CSI-RS resources configured by RRC. In some embodiments, the size of the MAC CE field is a fixed number of bits. In one example, the fixed number is the maximum number of associated CSI-RS resources (e.g., maxNrofSRS-InterferenceSuppression). In another example, the fixed number is ceil(log2C), where C is the maximum number of associated CSI-RS resources for interference suppression. In another example, for semi-persistent SRS, the network entity 410 may select one or more associated CSI-RS resource indexes via a MAC CE field (e.g., an associated CSI-RS resource index of a MAC CE), where the MAC CE field may be a bitmap and each bit indicates whether a specific CSI-RS is selected. In one implementation, the size of the MAC CE is a fixed number of bits. For example, the fixed number is equal to or greater than the maximum number of associated CSI-RS resources (e.g., maxNrofSRS-Suppression).

[0090] In one example, for aperiodic SRS, the network entity 410 may select an associated CSI-RS resource index from an associated CSI-RS resource list for interference suppression (e.g., interferenceMeasAssociatedCSI-RSList in the aperiodic field) through a DCI field (e.g., an associated CSI-RS resource index of the DCI). The bit width of the DCI field may be , where C is the number of candidate associated CSI-RS resources configured by RRC. In another example, for aperiodic SRS, the network entity 410 may select one or more associated CSI-RS resource indexes through a DCI field (e.g., associated CSI-RS resource index), where the DCI field may be a bitmap and each bit indicates whether a CSI-RS is selected.

[0091] Fig. 7AAn example signaling diagram 700 for precoder determination in a non-codebook (NCB) semi-persistent uplink scheme with multiple TRPs is illustrated in accordance with some embodiments. In one embodiment, the network entity 410 sends the associated CSI-RS to the UE device in a repetitive manner (e.g., periodically or semi-periodically). For periodic CSI-RS, the network entity 410 sends the associated CSI-RS based on a configured period and slot offset. For semi-persistent CSI-RS, the network entity 410 sends a MAC CE to activate the CSI-RS and sends the CSI-RS based on the configured period and slot offset. The network entity 410 may use a MAC CE such as Fig. 7A A single MAC CE as shown or Figure 7B A separate MAC CE is shown to trigger the associated semi-persistent CSI-RS and semi-persistent SRS resource sets.

[0092] exist Fig. 7A , the UE 102 sends 420 a UE capability report regarding uplink precoder selection for SRS with more than one associated CSI-RS to a network entity 410 (e.g., a gNB). The network entity 410 sends 430 control signaling to configure more than one associated semi-persistent CSI-RS for at least one semi-persistent SRS resource set. The network entity 410 then sends 740 a MAC CE to the UE device to activate the semi-persistent SRS and the associated semi-persistent CSI-RS. The network entity 410 sends 752 and 754 a plurality of first semi-persistent CSI-RS-1 associated with the activated SRS. The network entity 410 sends 755 and 757 a plurality of second semi-persistent CSI-RS-2 associated with the activated SRS. Upon receiving the CSI-RS-1 and CSI-RS-2, the UE device 102 determines 760 a precoder for an SRS resource in the activated SRS resource set based on the received semi-persistent CSI-RS. The UE device 102 transmits 770 a semi-persistent SRS using the determined precoder to the network entity 410. The network entity 410 receives 780 the activated SRS.

[0093] Figure 7B Another example signaling diagram for precoder determination in a semi-persistent uplink scheme with multiple TRPs according to some embodiments is illustrated. The call flow diagram 702 is similar to the call flow diagram 700, except that the network entity 410 sends 742 and 744 two separate MAC CEs to activate the associated semi-persistent CSI-RS and semi-persistent SRS, respectively.

[0094] Fig. 8AAn example signaling diagram for precoder determination in an aperiodic uplink scheme using multiple TRPs according to some embodiments is illustrated. For an aperiodic CSI-RS, the network entity 410 may trigger the associated aperiodic CSI-RS resource and the corresponding SRS via an SRS request field in a DCI, such as Fig. 8A Alternatively, the network entity 410 may trigger the associated aperiodic CSI-RS resources and the corresponding SRS via a separate DCI, such as Figure 8B As shown. Fig. 8A , the network entity 410 sends 840 a DCI for triggering aperiodic SRS and associated aperiodic CSI-RS after sending 430 control signaling for configuring more than one associated aperiodic CSI-RS for at least one aperiodic SRS resource set. Then, the network entity 410 sends 850 and 855 aperiodic CSI-RS-1 and CSI-RS-2 (of the corresponding two TRPs) associated with the triggered aperiodic SRS. The UE device 102 determines 860 a precoder for the SRS resources in the triggered SRS resource set based on the received CSI-RS, and sends 870 the aperiodic SRS using the determined precoder. The network entity 410 receives 880 the aperiodic SRS.

[0095] In some embodiments, the network entity 410 sends the associated CSI-RS resource at a time slot having a time slot offset configured by RRC signaling from the time slot with the last symbol of the DCI. In some embodiments, the network entity 410 sends the associated CSI-RS resource in the same time slot as the time slot with the last symbol of the DCI. In some embodiments, the network entity 410 sends the associated CSI-RS at the reference time slot indicated by the DCI. The last symbol of the triggered associated CSI-RS resource should be at least Z symbols (including timing advance) before the first symbol of the triggered aperiodic SRS, where Z can be predefined, such as Z=42, or Z can be reported by the UE capability.

[0096] Figure 8B Another example signaling diagram for precoder determination in an aperiodic uplink scheme with multiple TRPs according to some embodiments is illustrated. Call flow diagram 802 is similar to call flow diagram 800, except that network entity 410 sends 842 and 844 two separate DCIs to trigger associated aperiodic CSI-RS and aperiodic SRS resource sets, respectively.

[0097] For an SRS resource having two associated CSI-RS resource lists, the network entity 410 may send the two associated CSI-RS resource lists in a first time slot. Alternatively, the network entity 410 may send the two associated CSI-RS resource lists in consecutive time slots, wherein the first list is sent from the first time slot and the second list is sent from the next time slot after the first time slot. In one example, the first time slot may be a time slot having a time slot offset configured by RRC signaling from a time slot having the last symbol of the DCI. In another example, the first time slot may be a time slot having the last symbol of the DCI. In another example, the first time slot may be a reference time slot indicated by the DCI.

[0098] In one embodiment, the UE may derive an uplink precoder based on the associated CSI-RS resource for each SRS resource in the SRS resource set and send precoded SRS resources based on the determined precoder.

[0099] In one example, if there are two or more associated CSI-RS resources for signal reception, the UE may derive the uplink precoder as follows:

[0100] in indicates the estimated channel for the associated CSI-RS resource k at subcarrier j; M is the number of associated CSI-RS resources.

[0101] In another example, the UE may derive the uplink precoder as follows:

[0102] in is the scaling factor k of the associated CSI-RS resource, and . In a certain implementation, the network entity 410 may configure the value of the scaling factor for each associated CSI-RS resource through RRC signaling. In a certain implementation, the network entity 410 may dynamically configure the value of the scaling factor for each associated CSI-RS through layer 1 or layer 2 signaling (e.g., DCI or MAC CE). In a certain implementation, the scaling factor is determined based on the linear reference signal received power (RSRP) of the associated CSI-RS resource. The network entity 410 may configure whether to enable the scaling factor through RRC signaling. In one example, it may be calculated as follows:

[0103] In another example, if there is at least one associated CSI-RS resource for interference suppression, the UE may derive the precoder based on the associated CSI-RS for signal reception and the associated CSI-RS for interference suppression. In one example, the UE calculates the precoder for the SRS resource s in the resource set as follows:

[0104] where the precoder is the first row or matrix in the normalized case ; is the sth column of the eigenvector V calculated from the associated CSI-RS for signal reception; is the first row of the eigenvector of the associated CSI-RS resource q for interference suppression; Q is the number of associated CSI-RS resources for interference suppression.

[0105] If the UE enables analog beamforming, the UE may determine an uplink transmission beam for sending a precoded SRS based on a downlink receive beam for receiving an associated CSI-RS for signal reception. In some embodiments, the UE receives the associated CSI-RS based on a single downlink receive beam. The UE may then send the precoded SRS based on a single uplink transmission beam, which is based on a single downlink for receiving the associated CSI-RS. In some embodiments, the UE receives each associated CSI-RS based on a separate downlink receive beam. The UE may then send the precoded SRS based on more than one uplink beam, where each uplink transmission beam is based on a downlink for receiving each associated CSI-RS.

[0106] Fig. 9 An example signaling diagram for utilizing an associated CSI-RS for precoder determination and sending an uplink precoder report according to some embodiments is illustrated. As shown, call flow diagram 900 illustrates a process for sending 975 a precoder report for an SRS for antenna switching (AS). The precoder report provides a mechanism to maintain a common understanding between the network entity 410 and the UE device 102 about the precoder applied to the SRS (e.g., AS type SRS). The network entity 410 can recover the downlink channel based on the measurement of the precoded SRS for the AS, as follows: in indicates the estimated downlink channel at subcarrier j; is the estimated channel from the SRS for AS at subcarrier j; is the reported precoder.

[0107] The UE device 102 sends 920 a UE capability report regarding uplink precoder selection for SRS with more than one associated CSI-RS (similar to Figure 4 420 in operation 420). The UE device 102 receives 930 control signaling from the network entity 410 to configure more than one associated non-periodic CSI-RS for at least one non-periodic SRS resource set. The network entity 410 sends 940 control signaling to trigger an SRS resource set associated with at least one CSI-RS and a precoder report. Then, the network entity 410 sends 950 and 955, 959 multiple CSI-RS-1 and CSI-RS-2 associated with the triggered SRS. The UE device 102 determines 960 a precoder for the SRS sent in the triggered SRS resource set based on the received CSI-RS. The UE device 102 uses the determined precoder to send 970 the triggered SRS and sends 975 a precoder report to the network entity 410. The network entity 410 receives 980 the non-periodic SRS and the precoder report.

[0108] Unlike conventional operations, in aspects of the present disclosure, the network entity 410 sends 930 control signaling related to precoder reporting to the UE, which control signaling may include parameters for precoder quantization and uplink resources for precoder reporting. In addition, the network entity 410 may send 930 control signaling to configure at least one associated CSI-RS for an SRS resource set for the UE to calculate the precoder. The network entity 410 may send an RRC message (e.g., an RRCReconfiguration message) including such control signaling. Alternatively, the network entity 410 may send certain control signaling, such as uplink resources for precoder reporting, via a MAC CE or a DCI.

[0109] In some cases, the network entity 410 may further trigger the precoder report via MAC CE or DCI. For semi-persistent SRS and semi-persistent precoder report, the network entity 410 may activate the precoder report via MAC CE. For aperiodic SRS and aperiodic precoder report, the network entity 410 may trigger the precoder report via DCI.

[0110] In some cases, the UE may quantize the precoder based on received control signaling regarding the quantization parameter and send the precoder to the network entity 410 based on the uplink resources configured or indicated for the precoder report.

[0111] In some cases, the network entity 410 may estimate the downlink channel based on the received SRS and precoder reports, and determine a downlink precoder to use for downlink transmissions based on the downlink channel estimate.

[0112] Fig.10 1000 is a flow chart depicting a method for precoder determination and uplink precoder reporting by a UE device utilizing associated CSI-RS according to some embodiments. Flowchart 1000 illustrates the behavior of uplink precoder reporting utilizing associated CSI-RS by a UE device 102. As shown, the UE device sends 1020 UE capabilities 1020 regarding uplink precoder selection and reporting for SRS utilizing at least one associated CSI-RS. The UE device receives 1030 control signaling with at least one associated CSI-RS for SRS and uplink precoder reporting. The UE device receives 1040 a MACCE to activate semi-persistent SRS, associated semi-persistent CSI-RS, and semi-persistent precoder reporting. Alternatively, the UE device receives 1040 a DCI to trigger aperiodic SRS, associated aperiodic CSI-RS, and aperiodic precoder reporting. The UE device receives 1050 the associated CSI-RS, and determines 1060 a precoder based on the CSI-RS for signal reception and / or the CSI-RS for interference suppression, and quantizes the precoder based on a quantization parameter. The UE device sends 1070 an SRS based on the determined precoder and the quantized precoder at the configured or indicated uplink resource. The UE device sends 1075 a precoder report. In some cases, sending the precoder report is based on a quantized amplitude and a quantized phase of each precoding weight coefficient as configured by radio resource control (RRC) signaling.

[0113] Fig.11is a flow chart depicting a method for precoder determination and receiving uplink precoder reports by a network entity using associated CSI-RS according to some embodiments. Flowchart 1100 illustrates network-side (gNB) behavior for uplink precoder reports using associated CSI-RS. The method shown in flowchart 1100 on the network entity side may correspond to the method of flowchart 1000 on the UE device side. The network entity (optionally) receives 1120 UE capabilities regarding uplink precoder selection and reporting for SRS using at least one associated CSI-RS. The network entity sends 1130 control signaling with at least one associated CSI-RS for SRS and uplink precoder reports. The network entity (optionally) sends 1140 a MAC CE to activate semi-persistent SRS, associated semi-persistent CSI-RS, and semi-persistent precoder reports. Alternatively, the network entity sends a DCI to trigger aperiodic SRS, associated aperiodic CSI-RS, and aperiodic precoder reports. The network entity sends 1150 the associated CSI-RS to the UE device. The network entity receives 1170 the SRS and the quantized precoder at the configured or indicated uplink resources. The network entity identifies 1185 a downlink precoder based on the received SRS and precoder.

[0114] In one embodiment, for periodic SRS for AS, the network entity 410 may configure uplink resources for precoder reporting, such as a PUCCH resource list or PUCCH resources, through RRC signaling. The network entity 410 may further configure reporting periodicity and time slot offset. For semi-persistent SRS for AS, the network entity 410 may configure uplink resources for precoder reporting, such as a PUCCH resource list or PUCCH resources or PUSCH, through RRC signaling, and report periodicity and time slot offset. For PUSCH-based reporting, the network entity 410 may further configure PUSCH resources through DCI associated with a configured scheduling radio network temporary ID (CS-RNTI). For aperiodic SRS for AS, the network entity 410 may configure a reporting time slot offset list through RRC signaling, and indicate uplink resources, such as PUCCH or PUSCH, for precoder reporting through DCI. In one example, the DCI may be a DCI for triggering aperiodic SRS for AS. In another example, the DCI may be a separate DCI for triggering aperiodic SRS for AS.

[0115] In one example, the network entity 410 may configure the following RRC parameters (parameters underlined below) for precoder reporting.

[0116] In some embodiments, the network entity 410 may configure the precoder quantization-related parameters through RRC signaling, including at least one of the following: 1. The number of horizontal antenna ports (N1); 2. The number of horizontal oversampling factors (O1); 3. The number of horizontal antenna ports (N2); 4. The number of horizontal oversampling factors (O2); 5. The number of selected beams (L); 6. The number of strongest coefficients (Kc); 7. The number of bits used for the amplitude step of non-zero coefficients (X1); or 8. The number of bits used for the phase of the non-zero coefficients (X2).

[0117] In some embodiments, at least one of the above parameters may be predefined. For example, O1 and O2 may be defined as 1, X1 and X2 may be predefined as 3, and Kc may be predefined as N1*N2*U, where U is the total number of antenna ports across the SRS resources in the resource set.

[0118] In some embodiments, the UE quantizes and reports the precoder applied for the most recent SRS for the AS associated with the measured CSI-RS based on the received quantization scheme.

[0119] In some embodiments, the UE quantizes each coefficient based on the configured or predefined number of bits for the amplitude of the non-zero coefficient and the number of bits for the phase of the non-zero coefficient. In one example, the amplitude can be quantized as [0, In another example, the phase can be quantized as [ , , ,…,1]. The UE may then report to the network entity 410 the amplitude and phase of each coefficient from the precoder applied to the precoded SRS.

[0120] In some embodiments, the UE quantizes the precoder based on a two-stage precoder as follows: where W1 is the space domain basis and is selected from a codebook generated as follows: in represents the Kronecker product. The codebook contains precoders with different values ​​of m and n. Denoting the codebook as W, W1 and W2 can be based on To calculate, where W1 is the matrix The strongest 2L row of , and W2 includes the space domain basis combination factor, where The UE may then report the L beam indices selected from the codebook and the strongest Kc coefficient of W2 and the index within W2 for the strongest Kc coefficient.

[0121] Fig.12 is a flowchart depicting a method for precoder selection by a UE device in a multi-TRP application according to some embodiments. The method is performed by processing logic, which includes hardware (e.g., circuit system, dedicated logic, programmable logic, processor, processing device, central processing unit (CPU), system on chip (SoC), etc.), software (e.g., instructions and / or applications running / executed on a processing device), firmware (e.g., microcode), or a combination thereof. The method of flowchart 1200 is performed by a UE device such as UE device 102. The UE device may include one or more radio frequency (RF) modems, a processor coupled to the one or more RF modems, and at least one non-volatile memory storing executable instructions for manipulating at least one of the processor or the RF modem to perform the method of flowchart 1200. A network entity may perform complementary methods to perform the method (e.g., see Figure 4 and Fig. 7A Interact with a UE device of the calling flowcharts 400 and 700).

[0122] refer to Fig.12 , flowchart 1200 illustrates example functionality used by various embodiments. Although specific functional blocks ("boxes") are disclosed in flowchart 1200, such blocks are examples. That is, the embodiments are well suited to performing various other boxes or variations of boxes listed in the method. It should be understood that the boxes in the method can be executed in an order different from the order presented, and not all boxes in the method can be executed.

[0123] like Fig.12 As shown, the UE device receives 1250 a first CSI-RS (with Figure 4 450 Fig. 8A 850 and the like). For example, the first network entity may include a first TRP among the plurality of TRPs. The UE device receives 1255 a second CSI-RS (similar to 850 of the plurality of TRPs) from the second network entity (e.g., a second TRP among the plurality of TRPs). Figure 4455 or Fig. 8A 855 is similar).

[0124] The UE device receives 1230 control signaling indicating at least one SRS resource set associated with at least the first CSI-RS or the second CSI-RS from the network entity (with Figure 4 , Fig. 8A and Figure 8B The UE device transmits 1270 one or more precoded SRSs in at least one SRS resource set to the first network entity using a precoder calculated based on at least the first CSI-RS and the second CSI-RS.

[0125] In some embodiments, the UE device further receives a third CSI-RS from at least a third network entity. The UE device determines a precoder for sending one or more precoded SRSs based on the first CSI-RS, the second CSI-RS, and the third CSI-RS, so that the precoded SRSs suppress interference with signals received at least at the third network entity.

[0126] In some embodiments, the UE device further receives a second control signaling from the first network entity for triggering at least one SRS resource set, the second control signaling being associated with a first CSI-RS corresponding to the second control signaling or a second CSI-RS corresponding to the second control signaling. The first network entity and the second network entity are transparent to each other.

[0127] In some embodiments, the UE device further sends an indication to the first network entity that the UE device is capable of uplink precoder selection for the SRS associated with more than one CSI-RS (e.g., CSI-RS in a multi-TRP scenario, not just more than one instance from a single TRP). For example, the indication may include at least one of the following: (1) a maximum number of associated CSI-RS resources for signal reception for an SRS resource set for a non-codebook (NCB) uplink transmission scheme; (2) a maximum number of associated CSI-RS resources for interference suppression for an SRS resource set for NCB; (3) the UE supports associated CSI-RS resources for an SRS resource set for antenna switching (AS); (4) a maximum number of associated CSI-RS resources for signal reception for an SRS resource set for AS; or (5) a maximum number of associated CSI-RS resources for interference suppression for an SRS resource set for AS.

[0128] In some embodiments, receiving control signaling (e.g., first control signaling) includes at least one of: receiving a first CSI-RS resource list associated with signal reception at a UE device, the first CSI-RS list including at least a first CSI-RS or a second CSI-RS; or receiving a second CSI-RS resource list associated with interference suppression caused by signal transmission at the UE device, the second CSI-RS list including a third CSI-RS from a victim network entity.

[0129] In some embodiments, receiving control signaling (eg, second control signaling) includes receiving radio resource control (RRC) signaling from the first network entity or the second network entity.

[0130] In some embodiments, the UE device further receives a medium access control (MAC) control element (CE) for activating the semi-persistent SRS and the associated semi-persistent CSI-RS. Alternatively, the UE device further receives downlink control information (DCI) for triggering the aperiodic SRS and the associated aperiodic CSI-RS.

[0131] In some embodiments, the MAC-CE or DCI jointly triggers the SRS resource set and the associated first CSI-RS or second CSI-RS at the UE device.

[0132] In some embodiments, the UE device reduces the selection of CSI-RS resources for precoder selection through an indication in a MAC-CE or DCI.

[0133] In some embodiments, the UE device receives a third control signaling indicating a physical uplink shared channel (PUSCH) resource or a physical uplink control channel (PUCCH) resource. The UE device uses the indicated PUSCH resource or PUCCH resource to send a precoder report to the first network entity. In some cases, the third control signaling includes at least one of RRC, MACCE, or DCI (for example, but not limited to PDCCH).

[0134] In some embodiments, the one or more precoded SRS resources in the at least one SRS resource set include SRS resources in an SRS resource set for NCB; or SRS resources in an SRS resource set for antenna switching (AS).

[0135] In some embodiments, sending a precoder report is based on: at least one spatial domain basis (e.g., The control signaling includes at least one coefficient indicating a spatial domain basis combining factor (e.g., a Kc coefficient of W2), and an index to the reported coefficient. In some cases, the control signaling includes radio resource control (RRC) signaling that configures at least one of the following: the number of horizontal antenna ports, the number of horizontal oversampling factors, the number of vertical antenna ports, the number of vertical oversampling factors, the number of spatial bases, or at least one coefficient associated with a strong signal.

[0136] Fig.13 is a flowchart depicting a method for precoder determination by a network entity in a multi-TRP application according to some embodiments. The method is performed by processing logic, which includes hardware (e.g., circuit system, dedicated logic, programmable logic, processor, processing device, central processing unit (CPU), system on chip (SoC), etc.), software (e.g., instructions and / or applications running / executed on a processing device), firmware (e.g., microcode), or a combination thereof. The method of flowchart 1000 is performed by a UE device. The network entity may include one or more radio frequency (RF) modems, a processor coupled to the one or more RF modems, and at least one non-volatile memory storing executable instructions to manipulate at least one of the processor or RF modems to perform the method of flowchart 1000. The network entity may perform a complementary method of flowchart 1000 to perform the method (e.g., see Figure 4 and Fig. 7A Interact with a UE device of the calling flow charts 400 and 700, etc.).

[0137] refer to Fig.13 , flowchart 1300 illustrates example functionality used by various embodiments. Although specific functional blocks ("blocks") are disclosed in flowchart 1300, such blocks are examples. That is, embodiments are well suited to performing various other blocks or variations of blocks listed in the method. It should be understood that the blocks in the method may be executed in an order different from the order presented, and not all blocks in the method may be executed.

[0138] like Fig.13 As shown, the network entity sends 1320 control signaling indicating at least one SRS resource set to the UE device (with Figure 4 The network entity sends 1350 a CSI-RS associated with at least one SRS resource set (similar to 430 of FIG. 1 ). Figure 4 1450 and 1455, Fig. 7A 752, 755, 754 and 757, or Fig. 8A850 and 855 are similar). The network entity receives 1370 one or more precoded SRS resources in at least one SRS resource set. The one or more precoded SRS resources are precoded based on the CSI-RS sent by the network entity and at least a second CSI-RS sent by a second network entity (e.g., a second target TRP in a multi-TRP scenario).

[0139] Unless specifically noted otherwise, terms such as "establish", "receive", "send", etc. refer to actions and processes performed or implemented by a computing device that manipulate data represented as physical (electronic) quantities within registers and memories of the computing device into other data similarly represented as physical quantities within the computing device memory or registers or other such information storage, transmission or display devices. In addition, the terms "first", "second", "third", "fourth", etc. as used herein are intended as labels to distinguish different elements and may not necessarily have ordinal meanings according to their numerical designations.

[0140] The examples described herein also relate to an apparatus for performing the operations described herein. This apparatus may be specially constructed for the desired purpose, or the apparatus may include a general-purpose computing device selectively programmed by a computer program stored in the computing device. Such a computer program may be stored in a computer-readable non-transitory storage medium.

[0141] The methods and illustrative examples described herein are not inherently related to any particular computer or other device. Various general purpose systems may be used according to the teachings described herein, or more specialized devices may be conveniently constructed to perform the required method steps. The required structures of a variety of these systems will be presented as described above.

[0142] The above description is intended to be illustrative rather than restrictive. Although the present disclosure has been described with reference to specific illustrative examples, it will be appreciated that the present disclosure is not limited to the described examples. The scope of the present disclosure should be determined with reference to the following claims and the full scope of equivalents to which the claims are authorized.

[0143] As used herein, the singular forms "a", "an", "an", "the", and "said" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should be further understood that the terms "include", "comprises", and / or "contains" when used herein specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. Therefore, the terminology used herein is for the purpose of describing specific embodiments only and is not intended to be limiting.

[0144] It should also be noted that in some alternative implementations, the functions / actions noted may not occur in the order noted in the figures. For example, two figures shown in succession may actually be performed substantially simultaneously or may sometimes be performed in reverse order, depending on the functionality / actions involved.

[0145] Although the method operations are described in a particular order, it should be understood that other operations may be performed between the described operations, that the described operations may be adjusted so that they occur at slightly different times, or that the described operations may be distributed in a system that allows the processing operations to occur at various intervals associated with the process.

[0146] Various units, circuits, or other components may be described or claimed as being "configured to" or "configurable to" perform one or more tasks. In such contexts, the phrases "configured to" or "configurable to" are used to represent a structure by indicating that a unit / circuit / component includes a structure (e.g., a circuit system) that performs one or more tasks during operation. Thus, even if a specified unit / circuit / component is not currently operating (e.g., not turned on), it can be said that the unit / circuit / component is configured to perform a task, or is configurable to perform a task. Units / circuits / components used with the "configured to" or "configurable to" language include hardware - e.g., circuits, memory storing program instructions executable to implement operations, etc. The recitation that a unit / circuit / component is "configured to" perform one or more tasks, or "configurable to" perform one or more tasks is expressly intended not to invoke the sixth paragraph of 35 USC §112 with respect to that unit / circuit / component. Additionally, "configured to" or "configurable to" may include general structures (e.g., general circuitry) manipulated by software and / or firmware (e.g., an FPGA or a general purpose processor executing software) to operate in a manner capable of performing the tasks in question. "Configured to" may also include adjusting a manufacturing process (e.g., a semiconductor manufacturing facility) to manufacture a device (e.g., an integrated circuit) suitable for implementing or performing one or more tasks. "Configurable to" is expressly intended not to apply to blank media, an unprogrammed processor or an unprogrammed general purpose computer, or an unprogrammed programmable logic device, programmable gate array, or other unprogrammed device, unless accompanied by a programming medium that imparts the unprogrammed device with the ability to be configured to perform the disclosed functionality.

[0147] For the purpose of explanation, the above description has been described with reference to specific embodiments. However, the above illustrative discussion is not intended to be exhaustive or to limit the present disclosure to the precise form disclosed. In view of the above teachings, many modifications and variations are possible. For example, dotted lines indicate optional operations in this article. The embodiments are selected and described in order to best explain the principles of the embodiments and their practical application, so as to enable those skilled in the art to best utilize the embodiments and various modifications that may be suitable for the intended specific use. Therefore, the embodiments of the present invention are considered to be illustrative rather than restrictive, and the present disclosure is not limited to the details given herein, but may be modified within the scope and equivalents of the appended claims. Example UE Example:

[0148] 1. A device, comprising: a processor, the processor being configured to cause a user equipment (UE): receiving control signaling indicating at least one sounding reference signal (SRS) resource set associated with at least two channel state information reference signals (CSI-RS); receiving an associated CSI-RS; determining a precoder based on the received associated CSI-RS; The SRS resources in the SRS resource set are transmitted based on the determined precoder.

[0149] 2. The apparatus of example 1, wherein the SRS is an SRS for uplink non-codebook (NCB) based transmission.

[0150] 3. The apparatus of example 1, wherein the SRS is an SRS for antenna switching (AS).

[0151] 4. A device according to Example 1, wherein the UE further sends a UE capability for SRS utilizing at least one associated channel state information reference signal (CSI-RS), the UE capability including at least one of the following elements: a maximum number of associated CSI-RS resources for signal reception for an SRS resource set for an NCB, a maximum number of associated CSI-RS resources for interference suppression for an SRS resource set for an NCB; whether the UE supports associated CSI-RS resources for an SRS resource set for an AS; a maximum number of associated CSI-RS resources for signal reception for an SRS resource set for an AS; a maximum number of associated CSI-RS resources for interference suppression for an SRS resource set for an AS.

[0152] 5. The apparatus of Example 1, wherein the control signaling may include a first CSI-RS resource list for signal reception.

[0153] 6. The apparatus of Example 1, wherein the control signaling may include a second CSI-RS resource list for interference suppression.

[0154] 7. The apparatus according to Examples 1, 5 and 6, wherein the control signaling may be RRC signaling.

[0155] 8. The apparatus of Example 7, wherein further downward selection of CSI-RS resources for precoder selection may be indicated by a MAC control element (CE).

[0156] 9. The apparatus of Example 7, wherein further downward selection of CSI-RS resources for precoder selection may be indicated by downlink control information (DCI).

[0157] 10. The device according to Example 1, wherein the associated CSI-RS and the SRS resource set can be jointly triggered by a DCI field or a MAC CE.

[0158] 11. The apparatus of Example 1, wherein the UE determines the precoder based on the associated CSI-RS for signal reception and the associated CSI-RS for interference suppression.

[0159] 12. The apparatus of Example 11, wherein the UE transmits the precoder via a PUCCH or a PUSCH.

[0160] 13. The apparatus of Example 12, wherein the PUCCH or PUSCH resource is configured via RRC signaling.

[0161] 14. The apparatus of Example 12, wherein the PUCCH or PUSCH resource is configured via a MAC CE.

[0162] 15. The apparatus of Example 12, wherein the PUCCH or PUSCH resource is indicated by a DCI.

[0163] 16. An apparatus according to Example 12, wherein the UE reports the precoder based on the quantized amplitude and phase of each coefficient.

[0164] 17. The apparatus of Example 16, wherein the number of bits used for amplitude quantization is configured via RRC signaling.

[0165] 18. The apparatus of Example 16, wherein the number of bits used for phase quantization is configured via RRC signaling.

[0166] 19. An apparatus according to Example 12, wherein the UE reports the precoder based on at least one spatial domain basis, at least one strongest coefficient, and an index for the reported coefficient.

[0167] 20. The apparatus of Example 19, wherein at least one of the following parameters is configured via RRC signaling: the number of horizontal antenna ports, the number of horizontal oversampling factors, the number of vertical antenna ports, the number of vertical oversampling factors, and the number of spatial bases.

[0168] 21. The apparatus of Example 19, wherein the number of strongest coefficients reported is configured via RRC signaling. BS Example

[0169] 1. An apparatus, comprising: a processor configured to cause a base station (BS): sending control signaling having at least one sounding reference signal (SRS) resource set associated with at least two channel state information reference signals (CSI-RS); Sending associated CSI-RS; The precoded SRS resources in the at least one SRS resource set are received.

[0170] 2. The apparatus of example 1, wherein the SRS is an SRS for uplink non-codebook (NCB) based transmission.

[0171] 3. The apparatus of example 1, wherein the SRS is an SRS for antenna switching (AS).

[0172] 4. The device according to Example 1, wherein the BS further receives UE capabilities, which include at least one of the following elements: a maximum number of associated CSI-RS resources for signal reception for an SRS resource set for an NCB, a maximum number of associated CSI-RS resources for interference suppression for an SRS resource set for an NCB; whether the UE supports associated CSI-RS resources for an SRS resource set for an AS; a maximum number of associated CSI-RS resources for signal reception for an SRS resource set for an AS; and a maximum number of associated CSI-RS resources for interference suppression for an SRS resource set for an AS.

[0173] 5. The apparatus of Example 1, wherein the control signaling may include a first CSI-RS resource list for signal reception.

[0174] 6. The apparatus of Example 1, wherein the control signaling may include a second CSI-RS resource list for interference suppression.

[0175] 7. The apparatus according to Examples 1, 5 and 6, wherein the control signaling may be RRC signaling.

[0176] 8. The apparatus of Example 7, wherein further downward selection of CSI-RS resources for precoder selection may be indicated by a MAC control element (CE).

[0177] 9. The apparatus of Example 7, wherein further downward selection of CSI-RS resources for precoder selection may be indicated by downlink control information (DCI).

[0178] 10. The device according to Example 1, wherein the associated CSI-RS and the SRS resource set can be jointly triggered by a DCI field or a MAC CE.

[0179] 11. The apparatus of Example 1, wherein the BS further receives a precoder applied to the most recent SRS through a PUCCH or a PUSCH.

[0180] 12. The apparatus of Example 12, wherein the PUCCH or PUSCH resource is configured via RRC signaling.

[0181] 13. The apparatus of Example 12, wherein the PUCCH or PUSCH resource is configured via a MAC CE.

[0182] 14. The apparatus of Example 12, wherein the PUCCH or PUSCH resource is indicated by a DCI.

[0183] 15. An apparatus according to example 11, wherein the precoder is reported based on the quantized amplitude and phase of each coefficient.

[0184] 16. The apparatus of Example 15, wherein the number of bits used for amplitude quantization is configured via RRC signaling.

[0185] 17. The apparatus of Example 15, wherein the number of bits used for phase quantization is configured via RRC signaling.

[0186] 18. An apparatus according to Example 11, wherein the precoder is reported based on at least one spatial domain basis, at least one strongest coefficient, and an index for the reported coefficient.

[0187] 19. An apparatus according to Example 18, wherein at least one of the following parameters is configured through RRC signaling: the number of horizontal antenna ports, the number of horizontal oversampling factors, the number of vertical antenna ports, the number of vertical oversampling factors, and the number of spatial bases.

[0188] 20. The apparatus of Example 18, wherein the number of strongest coefficients reported is configured via RRC signaling.

Claims

1. A method for determining a precoder by a user equipment (UE), the method comprising: Receiving, by the UE device, a first channel state information reference signal CSI-RS from a first network entity; receiving, by the UE device, a second CSI-RS from a second network entity; receiving, by the UE device from the first network entity, first control signaling indicating at least one sounding reference signal (SRS) resource set associated with at least the first CSI-RS or the second CSI-RS; as well as One or more precoded SRSs in the at least one SRS resource set are sent by the UE device to the first network entity using a precoder calculated based on at least the first CSI-RS and the second CSI-RS.

2. The method of claim 1, further comprising: receiving, by the UE device, a third CSI-RS from a third network entity; as well as At the UE device, the precoder for sending the one or more precoded SRSs is determined based on at least the first CSI-RS, the second CSI-RS, and the third CSI-RS, so that the precoded SRS resources suppress interference with the signal received at the third network entity.

3. The method according to claim 1 or 2, further comprising: Second control signaling for triggering sending of the one or more precoded SRSs is received by the UE device from the first network entity, wherein the second control signaling is associated with at least the first CSI-RS or the second CSI-RS.

4. The method according to any one of claims 1 to 3, further comprising: An indication is sent to the first network entity that the UE device is capable of uplink precoder selection for an SRS associated with more than one CSI-RS.

5. The method of claim 4, wherein sending the indication comprises sending at least one of: (1) The maximum number of associated CSI-RS resources for signal reception for an SRS resource set for non-codebook NCB; (2) The maximum number of associated CSI-RS resources for interference mitigation for an SRS resource set used for NCB; (3) the UE supports associated CSI-RS resources for an SRS resource set for an antenna switching AS; (4) the maximum number of associated CSI-RS resources for signal reception for an SRS resource set for an AS; or (5) The maximum number of associated CSI-RS resources for interference suppression for an SRS resource set for an AS.

6. The method of any one of claims 1 to 5, wherein receiving the first control signaling comprises at least one of the following: receiving a first CSI-RS resource list associated with signal reception at the UE device, the first CSI-RS list including at least the first CSI-RS or the second CSI-RS; and A second CSI-RS resource list associated with interference mitigation caused by signal transmission at the UE device is received, the second CSI-RS list including at least a third CSI-RS from a victim network entity.

7. The method according to any one of claims 1 to 6, wherein receiving the first control signaling comprises: Radio Resource Control (RRC) signaling is received from the first network entity or the second network entity.

8. The method according to any one of claims 3 to 7, wherein receiving the second control signaling comprises: A medium access control MAC control element CE for activating a semi-persistent SRS and an associated semi-persistent CSI-RS is received.

9. The method according to any one of claims 3 to 7, wherein receiving the second control signaling comprises: Downlink control information DCI for triggering an aperiodic SRS and an associated aperiodic CSI-RS is received.

10. The method of claim 8 or 9, further comprising: The SRS resource set and the associated first CSI-RS and / or second CSI-RS are jointly triggered at the UE device through the MAC-CE or the DCI.

11. The method of claim 8 or 9, further comprising: The selection of CSI-RS resources for precoder selection is reduced through an indication in the MAC-CE or the DCI.

12. The method of claim 8 or 9, further comprising: receiving a third control signaling indicating a physical uplink shared channel PUSCH resource or a physical uplink control channel PUCCH resource; as well as A precoder report is sent to the first network entity using the indicated PUSCH resources or PUCCH resources.

13. The method of claim 12, wherein sending the precoder report is based on: The quantized amplitude and quantized phase of each precoding weight coefficient as configured through radio resource control RRC signaling.

14. The method of claim 12, wherein the third control signaling comprises at least one of the following: Radio Resource Control RRC signaling; Media Access Control MAC Control Element CE; or Downlink Control Information DCI.

15. The method of any one of claims 1 to 14, wherein sending the one or more precoded SRS resources in the at least one SRS resource set comprises: Sending one or more SRS resources in an SRS resource set for a non-codebook NCB; or One or more SRS resources in the SRS resource set for the antenna switching AS are sent.

16. The method of claim 12, wherein sending the precoder report is based on: At least one spatial domain basis, at least one coefficient indicating a spatial domain basis combining factor, and Index to the reported coefficient.

17. The method of claim 16, wherein receiving the control signaling comprises: Receiving radio resource control (RRC) signaling configuring at least one of: The number of horizontal antenna ports, The amount of horizontal oversampling factor, The number of vertical antenna ports, The amount of vertical oversampling factor, the number of spatial bases, or Indicates the number of coefficients of the space domain basis combining factor.

18. A method for precoder determination by a network entity, the method comprising: Sending a first control signaling indicating at least one sounding reference signal (SRS) resource set associated with at least one channel state information reference signal (CSI-RS) to a user equipment (UE) device; Sending a channel state information reference signal (CSI-RS) associated with the at least one SRS resource set to the user equipment (UE) device; as well as One or more precoded SRSs in the at least one SRS resource set are received, the one or more precoded SRSs being precoded based on the CSI-RS sent by the network entity and at least a second CSI-RS sent by a second network entity.

19. The method of claim 18, wherein receiving the one or more precoded SRSs comprises: sending a third CSI-RS to the UE device; as well as The one or more precoded SRSs determined based on at least the CSI-RS, the second CSI-RS, and the third CSI-RS are received so that the one or more precoded SRSs suppress interference to a signal received at a third network entity associated with the third CSI-RS.

20. The method of claim 18 or 19, further comprising: Second control signaling is sent to the UE device for triggering transmission of the one or more precoded SRSs by the UE, wherein the second control signaling is associated with the first CSI-RS or the second CSI-RS.

21. The method of any one of claims 18 to 20, further comprising: An indication is received by the network entity that the UE device is capable of uplink precoder selection for SRS associated with CSI-RS from two or more network entities.

22. The method of claim 21 , wherein receiving the indication comprises receiving at least one of: (1) The maximum number of associated CSI-RS resources for signal reception for an SRS resource set for non-codebook NCB; (2) The maximum number of associated CSI-RS resources for interference mitigation for an SRS resource set used for NCB; (3) the UE supports associated CSI-RS resources for an SRS resource set for an antenna switching AS; (4) the maximum number of associated CSI-RS resources for signal reception for an SRS resource set for an AS; or (5) The maximum number of associated CSI-RS resources for interference suppression for an SRS resource set for an AS.

23. The method of any one of claims 18 to 22, wherein sending the first control signaling comprises at least one of: transmitting a first CSI-RS resource list associated with signal reception at the UE device, the first CSI-RS list including at least the first CSI-RS or the second CSI-RS; and A second CSI-RS resource list associated with interference mitigation caused by signal transmission at the UE device is transmitted, the second CSI-RS list including at least a third CSI-RS from a victim network entity.

24. The method according to any one of claims 18 to 23, wherein sending the first control signaling comprises: Radio Resource Control (RRC) signaling is sent from the network entity or the second network entity.

25. The method according to any one of claims 20 to 23, wherein sending the second control signaling comprises: A medium access control MAC control element CE for activating the semi-persistent SRS and the associated semi-persistent CSI-RS is sent.

26. The method according to any one of claims 18 to 23, wherein sending the second control signaling comprises: Downlink control information DCI for triggering aperiodic SRS and associated aperiodic CSI-RS is transmitted.

27. The method of claim 25 or 26, further comprising: The SRS resource set and the associated first CSI-RS and / or second CSI-RS are jointly triggered at the UE device through the MAC-CE or the DCI.

28. The method of claim 25 or 26, further comprising: The selection of CSI-RS resources for precoder selection is reduced through an indication in the MAC-CE or the DCI.

29. The method of claim 25 or 26, further comprising: Sending a third control signaling indicating a physical uplink shared channel (PUSCH) resource or a physical uplink control channel (PUCCH) resource to the UE device; as well as A precoder report is received from the UE device in the indicated PUSCH resources or PUCCH resources.

30. The method of claim 29, wherein receiving the precoder report is based on: A radio resource control (RRC) message is sent to the UE device to configure a quantized amplitude and a quantized phase of each precoding weight coefficient for the precoder report.

31. The method of claim 29, wherein sending the third control signaling to the UE device comprises sending at least one of: Radio Resource Control RRC signaling; Media Access Control MAC Control Element CE; or Downlink Control Information DCI.

32. The method of any one of claims 18 to 31, wherein receiving the one or more precoded SRSs in the at least one SRS resource set comprises: receiving one or more SRSs in an SRS resource set for a non-codebook NCB; or One or more SRSs in an SRS resource set for an antenna switching AS are received.

33. The method according to any one of claims 18 to 26, wherein sending the first control signaling comprises: Sending radio resource control (RRC) signaling that configures at least one of the following: The number of horizontal antenna ports, The amount of horizontal oversampling factor, The number of vertical antenna ports, The amount of vertical oversampling factor, the number of spatial bases, or Indicates the number of coefficients of the spatial domain basis combining factor.

34. A user equipment UE, comprising: one or more radio frequency (RF) modems; a processor coupled to the one or more RF modems; as well as At least one memory storing executable instructions for manipulating at least one of the processor or the one or more RF modems to perform the method of any one of claims 1 to 17.

35. A network entity comprising: one or more radio frequency (RF) modems; a processor coupled to the one or more RF modems; as well as At least one memory storing executable instructions for manipulating at least one of the processor or the one or more RF modems to perform the method of any one of claims 18 to 33.

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