CONFIGURATION

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 62/963,209 filed January 20, 2020, and U.S. Provisional Application No. 63/050,898 filed July 13, 2020, the entirety of both of which is incorporated by reference herein.

TECHNICAL FIELD

[0002] Embodiments of the invention relate to wireless communications; more specifically, to the configuration of a sounding reference signal (SRS) resource set.

BACKGROUND

[0003] The Fifth Generation New Radio (5G NR) is a telecommunication standard for mobile broadband communications. NR is promulgated by the 3rd Generation Partnership Project (3GPP) to significantly improve performance metrics such as latency, reliability, throughput, etc. Furthermore, NR supports beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation.

[0004] In a 5G NR network, a user equipment (UE) can transmit one or more uplink reference signals, including a sounding reference signal (SRS), to a base station. Based on measurements of the reference signals, the base station can, for example, calculate uplink channel quality, select an uplink beam, and allocate uplink resources. A UE transmits an SRS according to an SRS resource set configuration. The configuration can be transmitted from a BS to the UE via radio resource control (RRC) signaling.

[0005] In the downlink, a base station can transmit one or more reference signals, including a channel state information reference signal (CSI-RS), to a UE. Base on measurements of the C SI RS, the UE can, for example, estimate downlink channel quality and obtain spatial information of the downlink transmission. The UE reports the estimated channel quality to the base station. The base station transmits downlink signals based on the report from the UE. For example, the base station can adapt the downlink data rate and modulation scheme based on the UE’s report. [0006] The existing 5G NR technology can be further improved to benefit operators and users. These improvements may also apply to other multi-access technologies and the telecommunication standards that employ these technologies.

SUMMARY

[0007] In one embodiment, a user equipment (UE) in a wireless network performs a method for updating a sounding reference signal (SRS) resource set configuration. The UE receives a medium access control (MAC) control element (CE) from a base station. The MAC CE is to update one or more parameter values in the SRS resource set configuration. The one or more parameter values include an identifier of a channel state information reference signal (CSI-RS). The UE receives the CSI-RS from the base station, and performs uplink transmission according to the SRS resource set configuration and based on a measurement of the CSI-RS.

[0008] In another embodiment, a UE in a wireless network performs a method for updating an SRS resource set configuration. The UE receives a MAC CE from a base station. The MAC CE is to update one or more parameter values in the SRS resource set configuration. The one or more parameter values include a slotOffset parameter value in the SRS resource set configuration. The UE performs uplink transmission according to timing information indicated by the slotOffset parameter value in the SRS resource set configuration.

[0009] In yet another embodiment, a UE in a wireless network is provided for wireless communication. The UE includes a memory to store an SRS resource set configuration; processing circuitry coupled to the memory and operative to update one or more parameter values in the SRS resource set configuration according to a MAC CE. The one or more parameter values include a slotOffset parameter value the SRS resource set configuration. The UE further includes transceiver circuitry operative to perform uplink transmission according to timing information indicated by the slotOffset parameter value in the SRS resource set configuration.

[0010] In other embodiments, the one or more parameter values updated by a MAC CE include one or more of the following: aperiodicSRS-ResourceTrigger, aperiodicSRS-ResourceTriggerList, slotOffset, csi-RS, associatedCSI-RS, usage, alpha, pO, and the like.

[0011] Other aspects and features will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments in conjunction with the accompanying figures. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The present invention is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings in which like references indicate similar elements. It should be noted that different references to "an" or "one" embodiment in this disclosure are not necessarily to the same embodiment, and such references mean at least one. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to effect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

[0013] Figure l is a diagram illustrating a network in which a base station and a UE communicate according to one embodiment.

[0014] Figure 2 is a diagram illustrating beam management using SRS according to one embodiment.

[0015] Figure 3 is a diagram illustrating codebook-based uplink transmission according to one embodiment.

[0016] Figure 4 is a diagram illustrating non-codebook-based uplink transmission according to one embodiment.

[0017] Figure 5 is a diagram illustrating an example of an SRS resource set configuration according to one embodiment.

[0018] Figure 6A and 6B illustrate examples of a MAC CE according to some embodiments. [0019] Figure 7A is a flow diagram illustrating a method performed by a UE in a wireless network for updating an SRS resource set configuration according to one embodiment.

[0020] Figure 7B is a flow diagram illustrating a method performed by a UE in a wireless network for updating an SRS resource set configuration according to another embodiment.

[0021] Figure 8 is a flow diagram illustrating a method performed by a UE for non-codebook- based transmission according to one embodiment.

[0022] Figure 9 is a block diagram illustrating an apparatus that performs wireless communication according to one embodiment.

DETAILED DESCRIPTION

[0023] In the following description, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In other instances, well-known circuits, structures, and techniques have not been shown in detail in order not to obscure the understanding of this description. It will be appreciated, however, by one skilled in the art, that the invention may be practiced without such specific details. Those of ordinary skill in the art, with the included descriptions, will be able to implement appropriate functionality without undue experimentation.

[0024] Embodiments of the invention improve the reconfiguration latency of sounding reference signal (SRS) resource sets. In one embodiment, a base station may update a UE’s SRS resource set configuration via layer-2 (L2) signaling; e.g., via a medium access control (MAC) control element (CE). The reconfiguration latency of L2 signaling is lower than the reconfiguration latency of level-3 (L3) signaling (e.g., the radio resource control (RRC) signaling). Thus, when there is a change in the channel condition, the base station can quickly update the UE’s SRS resource set with a MAC CE to avoid signal degradation or failure in signal reception.

[0025] The term “SRS resource set configuration” is referred to as “SRS-ResourceSet” in the 3GPP Technical Specification (e.g., 3GPP TS 38.331, Version 15.7.0, October 2019). An SRS resource set includes one or more SRS resources, each of which is identified by a unique srs- ResourceSetld in the SRS resource set configuration. In one embodiment, each SRS resource corresponds to an uplink (UL) transmit (Tx) beam from a UE to a base station. An SRS resource set configuration provides a UE with uplink transmission information such as uplink resource scheduling, downlink (DL) reference signal identifier, SRS usage, power control indication, among others. An SRS resource set configuration includes multiple parameters and their corresponding parameter values. In one embodiment, a base station may use a MAC CE to update one or more of these parameter values.

[0026] The disclosed method, as well as the apparatus and the computer product implementing the method, can be applied to wireless communication between a base station (e.g., a gNB in a 5G NR network) and UEs. It is noted that while the embodiments may be described herein using terminology commonly associated with 5G or NR wireless technologies, the present disclosure can be applied to other multi-access technologies and the telecommunication standards that employ these technologies, such as Long Term Evolution (LTE) systems, future 3 GPP systems, IEEE protocols, and the like.

[0027] Figure 1 illustrates a wireless network 100 in which a base station (BS) 120 and a UE 150 communicate according to one embodiment. In some network environments such as a 5GNR network, the BS 120 may be known as a gNodeB, a gNB, and/or the like. In an alternative network environment, a base station may be known by other names. The BS 120 and the UE 150 transmit beamformed signals to each other. The UE 150 may also be known by other names, such as a mobile station, a subscriber unit, and/or the like. The UE 150 may be stationary or mobile. In practice, the network 100 may include additional devices, different devices, or differently arranged devices than those shown in Figure 1.

[0028] Examples of the UE 150 may include a cellular phone (e.g., a smartphone), a wireless communication device, a handheld device, a laptop computer, a tablet, a gaming device, a wearable device, an entertainment device, a sensor, an infotainment device, Internet-of-Things (IoT) devices, or any device that can communicate via a wireless medium. The UE 150 can be configured to receive and transmit signals over an air interface to one or more cells in a radio access network.

[0029] In one embodiment, the UE 150 provides layer-3 functionalities through a radio resource control (RRC) layer, which is associated with the transfer of system information, connection control, and measurement configurations. The UE 150 further provides layer-2 functionalities through a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a medium access control (MAC) layer. The PDCP layer is associated with header compression/decompression, security, and handover support. The RLC layer is associated with the transfer of packet data units (PDUs), error correction through automatic repeat request (ARQ), concatenation, segmentation, and reassembly of RLC service data units (SDUs). The MAC layer is associated with the mapping between logical channels and transport channels, multiplexing of MAC SDUs onto transport blocks (TBs), de-multiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through hybrid ARQ (HARQ), priority handling, and logical channel prioritization. The UE 150 further provides layer- 1 functionalities through a physical (PHY) layer, which is associated with error detection on the transport channels, forward error correction (FEC) coding/decoding of the transport channels, interleaving, rate matching, mapping onto physical channels, modulation/demodulation of physical channels, and multiple-input and multiple-output (MIMO) antenna processing, etc.

[0030] In a 5G NR network, a base station such as a gNB may configure and activate a bandwidth part (BWP) for communication with UEs in a serving cell, through an RRC configuration according to an RRC layer protocol. The activated BWP is referred to as the frequency resources, and the time scheduled for the communication is referred to as the time resources. The frequency resources and the time resources are herein collectively referred to as the time-and-frequency resources. In a wireless network, different serving cells may be configured with different time-and-frequency resources. Different time-and-frequency resources may be allocated to different physical uplink channels, physical downlink channels, uplink signals, and downlink signals. [0031] In one embodiment, both the BS 120 and the UE 150 include MIMO antenna arrays for performing beam steering and tracking in transmit (Tx) and receive (Rx) directions. In the example of Figure 1, the BS 120 forms beams BB#1, BB#2, BB#3, and BB#4 for downlink transmission and uplink reception, and the UE 150 forms beams UB#1, UB#2, UB#3, and UB#4 for uplink transmission and downlink reception. In an alternative embodiment, the BS 120 and/or the UE 150 may form a different number of beams than what is shown in Figure 1. Each beam corresponds to a spatial relation between the BS 120 and the UE 150. To the UE 150, a spatial relation is equivalent to spatial filtering that the UE 150 can apply in the analog and/or digital domain.

[0032] Physical signals, including data signals, control signals, and reference signals, are transmitted in both the uplink and downlink directions. Uplink reference signals may include demodulation reference signal (DMRS), phase tracking reference signal (PTRS), SRS, among others, and downlink reference signals may include DMRS, PTRS, CSI-RS, synchronization signal block (SSB), among others. Figure 1 shows that the uplink signals include SRS#1, SRS#2, SRS#5, and SRS#6, each transmitted from a different Tx beam. The downlink signals include, among others, a CSI-RS. In some embodiments, the UE may simultaneously transmit those SRSs that belong to different SRS resource sets. The following description provides further details about SRS and CSI-RS, as the configuration of each SRS resource includes a corresponding CSI-RS. In one embodiment, a UE may use the information calculated from the CSI-RS for non-codebook-based transmission.

[0033] A base station transmits downlink reference signals to a UE or a group of UEs in a serving cell. One of the reference signals is a CSI-RS. A base station can configure a set of time-and- frequency resources for a CSI-RS configuration used by the UE to receive one or more CSI-RSs. According to the CSI-RS configuration, the UE receives a CSI-RS from a target Rx beam direction with the given time-and-frequency resources for channel quality estimation, frequency, and time tracking, among other uses. A CSI-RS may be periodic, aperiodic, or semi-persistent. Based on the received CSI-RS, the UE calculates and reports channel state information (CSI) to the base station. The reported CSI indicates the quality of the radio channel or link between an antenna port of the base station and the UE. Based on the CSI report, the base station can determine a MIMO precoding scheme and the number of UE-preferred transmission layers, respectively, for downlink transmission.

[0034] For uplink transmissions, an SRS is an uplink physical signal that enables a base station to estimate the channel quality over a range of frequencies. An SRS can be periodic, aperiodic, or semi -persistent. The base station may determine a precoder matrix for downlink transmission to match the channel characteristics measured from the SRS. The base station may also send a TPMX and transmission rank indicator (TRI) to the UE, which may be used by the UE to determine a MEMO precoding scheme and the number of transmission layers, respectively, for uplink transmission

[0035] An SRS resource set configuration identifies the SRS resources available for transmitting SRSs, and also identifies a CSI-RS to aid the UE for uplink transmission. When Tx/Rx reciprocity holds in time-division duplex (TDD) transmission, the UE may use measurements of the CSI-RS for transmission of SRS, physical uplink control channel (PUCCH), and physical uplink shared channel (PUSCH).

[0036] A UE may be configured with multiple SRS resource sets with different usages. An SRS resource set configuration indicates the usage of the SRS resource set, such as beam management, codebook-based transmission, non-codebook-based transmission, or antenna switching. The process of antenna switching is used to sound all antennas, taking into account that UEs typically have more receive (RX) chains than transmit (TX) chains. The processes of beam management, codebook-based transmission, and non-codebook-based transmission are described below with reference to Figures 2, 3, and 4.

[0037] Figure 2 is a diagram illustrating a base station (e.g., the BS 120 in Figure 1) and a UE (e.g., the UE 150 in Figure 1) using SRS for a beam management process 200 according to one embodiment. The UE is configured with one or more SRS resource sets, and each SRS resource set includes one or more SRS resources. The base station may configure an SRS resource set of the UE for beam management by setting its “usage” parameter to “beamManagement.”

[0038] The beam management process 200 includes the UE transmits SRSs to the base station, and the base station transmits a beam indication to the UE based on measurements of the SRSs. In this example, the UE is configured with two SRS resource sets: SRS-ResourceSet#l and SRS- ResourceSet#2, where SRS-ResourceSet#l includes SRS#1 and SRS#2, and SRS-ResourceSet#2 includes SRS#5 and SRS#6. In one embodiment, different SRSs are transmitted in different Tx beams, and only one SRS in each SRS resource set may be transmitted at a given time instant. In one embodiment, different SRSs in the same SRS resource set may be transmitted from the same antenna panel in different Tx beams at different time instants. SRSs from different SRS resource sets may be transmitted simultaneously in different Tx beams. At step 210, the UE simultaneously transmits two SRSs, one from each SRS resource set. For example, SRS#1 and SRS#5 are transmitted at time tl, and then SRS#2 and SRS#6 are transmitted at time t2. The base station measures the signal strength from each of SRS#1, SRS#2, SRS#5, and SRS#6. The base station at step 215 determines the SRS (corresponds to a Tx beam) having the strongest signal; e.g., SRS#2 in the example of Figure 1. The base station at step 220 sends a beam indication to the UE to indicate the strongest SRS. The beam indication may be an SRS resource indicator (SRI) indicating the SRS resource having the strongest SRS (i.e., the strongest Tx beam). In one embodiment, the base station sends downlink control information (DCI) to the UE, where the DCI includes the SRI. The UE at step 230 can use the indicated SRS resource for PUSCH, PUCCH, and SRS transmissions. The transmission may be codebook-based or non-codebook-based.

[0039] Figure 3 is a diagram illustrating a codebook-based transmission process 300 according to one embodiment. The base station may configure an SRS resource set of the UE for codebook- based transmission by setting its “usage” parameter to “codebook” in the SRS resource set configuration.

[0040] The codebook-based transmission process 300 shown in Figure 3 is a close-loop precoding process. The UE at step 310 transmits an SRS to the base station. The base station at step 315 estimates the uplink channel condition based on the SRS, and, accordingly, selects a precoder matrix (a.k.a. precoder) from a codebook of candidate precoder matrices. The base station at step 320 indicates this selected precoder matrix to the UE by sending a Transmit precoder matrix indicator (TPMI) to the UE. The base station at step 320 also sends a transmission rank indicator (TRI) to the UE to indicate the number of transmission layers (i.e., symbol streams) to be transmitted by the UE’s antennas. The base station at step 320 may also send an SRS resource indicator (SRI) to the UE to identify an SRS resource in the SRS resource set for use in precoded transmission. The UE at step 325 applies the precoder to uplink transmission, and at step 330 transmits precoded transmission of SRS, PUSCH, and PUCCH.

[0041] Figure 4 is a diagram illustrating a non-codebook-based transmission process 400 according to one embodiment. The base station may configure an SRS resource set of the UE for non-codebook-based transmission by setting its “usage” parameter to “non-codebook” in the SRS resource set configuration. Non-codebook-based uplink transmission is applicable when Tx/Rx reciprocity holds at the UE (e.g., in the TDD mode).

[0042] For non-codebook based transmission, the UE determines one or more precoder candidates based on a downlink reference signal such as a CSI-RS transmitted from a base station at step 410. The UE at step 415 estimates the downlink channel from the CSI-RS, uses the downlink channel estimate as an estimate for the uplink channel, and calculates a set of precoder candidates based on the estimate. The UE at step 420 transmits one or more precoded SRSs in one or more SRS resources to the base station. The base station measures the precoded SRS, determines one or more preferred SRS, and instructs the UE to use the precoder(s) applied to the one or more preferred SRS. The base station at step 430 may transmit an SRI to indicate to the UE which precoder to use. The UE at step 435 applies the precoder to uplink transmission, and at step 440 transmits precoded SRS, PUSCH, and PUCCH.

[0043] In the non-codebook based transmission process 400, a CSI-RS used by the UE for calculating the precoder candidates is specified in the configuration of each SRS resource set. In the SRS resource set configuration, the parameter that indicates the CSI-RS for an aperiodic SRS is “csi-RS,” and for a periodic or semi-persistent SRS is “associatedCSI-RS.” The target value (i.e., the target identifier) for “csi-RS” and “associatedCSI-RS” is identified by the parameter value NZP- CSI-RS-Resourceld. In one embodiment, the UE is configured with one NZP CSI-RS resource for an SRS resource set.

[0044] Figure 5 is a diagram illustrating a configuration of an SRS resource set (SRS-ResourceSet configuration 500) according to one embodiment. According to embodiments of the invention, a base station can update the SRS-ResourceSet configuration 500 via a MAC CE. A UE may be configured with multiple SRS resource sets; only one is shown in Figure 5. It is understood that the configuration 500 is simplified to show only some of the parameters in an SRS resource set; additional parameters may be included in alternative embodiments. The parameter values in the configuration 500 are shown in curly brackets; e.g., “target_value_i”, “m_taget_values” or ”n_target_values” where i is a running index.

[0045] SRS-ResourceSet is identified by its identifier srs-Re source Setld. SRS-ResourceSet includes one or more SRS-Resources, each of which is identified by a corresponding identifier in srs-ResourceldList. An SRS resource can be one of the three resource types: aperiodic, periodic, or semi-persistent. The trigger to an aperiodic SRS resource is specified in the configuration 500 as the parameter aperiodicSRS-ResourceTrigger or aperiodicSRS-ResourceTriggerList. In one embodiment, aperiodicSRS-ResourceTrigger or aperiodicSRS-ResourceTriggerList specifies a DCI code point upon which the UE transmits SRS according to this SRS resource set configuration. The slotOffset parameter indicates the timing of the trigger. In one embodiment, slotOffset is an offset in the number of slots between the triggering DCI and the actual transmission of this SRS resource set configuration. [0046] The configuration 500 includes the parameter value NZP-CSI-RS-ResourcelD for each resource type. NZP-CSI-RS-ResourcelD identifies a CSI-RS for the UE to estimate channel condition and to determine a precoder matrix. The configuration 500 also indicates a usage parameter for all the SRS resources in the SRS-ResourceSet. As mentioned before, the target value of usage parameter is beamManagement, codebook, nonCodebook, or antennaSwitching

[0047] Furthermore, the configuration 500 includes power control parameters. The power control parameters are configured per SRS resource set. The power control parameters include P0 and alpha for the UE to calculate the transmission power. The power control parameters may also identify a reference signal for path loss estimation (i.e., the parameter pathlossReferenceRS). The target value (i.e., an SSB index or NZP-CSI-RS-ResourcelD) of pathlossReferenceRS is used to measure the downlink reference signal received power (RSRP).

[0048] In one embodiment, the configuration 500 may be stored in a memory 540 of a UE, such as the UE 150. The UE 150 receives the configuration 500 via a MAC CE from a base station using a radio receiver (Rx) 510, and sends one or more SRSs according to the configuration 500 to the base station using a radio transmitter (Tx) 520. The UE 150 may also receive a CSI-RS identified in the configuration 500 and calculate one or more precoders based on the received CSI-RS using a processor 530. The UE may apply the one or more precoders to the subsequent uplink transmission of SRS, PUCCH, and PUSCH.

[0049] A MAC CE may be used to update one parameter value or multiple parameter values of the configuration 500. A MAC CE is a bit string that is byte aligned (e.g., multiple of 8 bits) in length. A MAC CE is part of a MAC subPDU; a MAC PDU consists of one or more MAC subPDUs.

[0050] Figure 6A is a diagram illustrating a MAC CE 610 according to one embodiment. The MAC CE 610 can be used to update the value of one parameter in an SRS resource set configuration (e.g., a parameter in the configuration 500 in Figure 5).

[0051] The MAC CE 610 includes three 8-bit segments (i.e., 3 bytes), with each byte shown as a row in the figure. The MAC CE 610 indicates a serving cell ID, a BWP ID, and an SRS resource set ID. The “field index” 630 indicates a parameter in the identified SRS resource set, and the “target value” 640 indicates the updated value of the parameter in 630. An example of the target value can be an updated NZP-CSI-RS-Resourceld. The “R” field is a reserved field.

[0052] Figure 6B is a diagram illustrating a MAC CE 620 according to another embodiment. The MAC CE 620 includes (2N + 2) bytes, where N is a positive integer. The MAC CE 620 can be used to update the values of N parameters in an SRS resource set configuration (e.g., N parameters in the configuration 500 in Figure 5).

[0053] The first two bytes of the MAC CE 620 indicate a serving cell ID, a BWP ID, and an SRS resource set ID. Each “field index” 611-i indicates a parameter in the identified SRS resource set, and the “target value” 621-i indicates the updated value of the corresponding parameter in 611-i, where i is a running index from 1 to N. The “R” field is a reserved field. The Έ” field indicates extension configurable to indicate an update to multiple parameter values in the SRS resource set configuration; it is configurable to indicate the existence of a next pair of (field index, target value). The E field is set to 0 to indicate the nonexistence of an extension. It is set to 1 to indicate the existence of an extension. It is understood that the binary values 0 and 1 may be reversed.

[0054] Figure 7A is a flow diagram illustrating a method 700 performed by a UE in a wireless network for updating an SRS resource set configuration according to one embodiment. The UE may be the UE 150 in Figures 1 and 5, and/or the apparatus 900 in Figure 9. The method 700 begins at step 710 when the UE receives a MAC CE from a base station, and uses the MAC CE to update one or more parameter values in an SRS resource set configuration. In one embodiment, the updated one or more parameter values include an identifier of a CSI-RS. The UE at step 720 receives the CSI-RS from the base station. The UE at step 730 performs uplink transmission according to the SRS resource set configuration updated by the MAC CE, and based on a measurement of the CSI-RS. In one embodiment, the uplink transmission may include transmission of SRS, PUSCH, and PUCCH from the UE to the base station.

[0055] Figure 7B is a flow diagram illustrating a method 701 performed by a UE in a wireless network for updating an SRS resource set configuration according to one embodiment. The UE may be the UE 150 in Figures 1 and 5, and/or the apparatus 900 in Figure 9. The method 701 begins at step 750 when the UE receives a MAC CE from a base station, and uses the MAC CE to update one or more parameter values in an SRS resource set configuration. In one embodiment, the updated one or more parameter values include a slotOffset parameter value in the SRS resource set configuration. The UE at step 760 performs uplink transmission according to timing information indicated by the slotOffset parameter value in the SRS resource set configuration. In one embodiment, the uplink transmission may include transmission of SRS, PUSCH, and PUCCH from the UE to the base station.

[0056] In one embodiment, the SRS resource set configuration may include a csi-RS field for aperiodic SRS, or an associatedCSI-RS field for semi-persistent SRS and periodic SRS. The MAC CE may update the values of the csi-RS/associatedCSI-RS field with the identifier NZP-CSI-RS- Resourceld. In one embodiment, the one or more parameter values updated by the MAC CE may include one or more values of the following parameters in the SRS resource set configuration: aperiodic-SRS-ResourceTrigger, aperiodic-SRS-ResourceTriggerList, slotOffset, usage, pO, alpha, pathlossReferenceRS, etc.

[0057] Figure 8 is a flow diagram illustrating a method 800 performed by a UE for non- codebook-based transmission according to one embodiment. The method 800 may be performed by the UE of Figure 7. The method 800 begins at step 810 when the UE determines an uplink precoder based on the CSI-RS received from the base station. The UE at step 820 precodes uplink signals using the uplink precoder. The UE at step 830 transmits precoded uplink signals to the base station. In one embodiment, the UE may transmit one or more precoded SRSs to the base station. In one embodiment, the UE may transmit data precoded with the uplink precoder to the base station via a PUSCH. In one embodiment, the UE may transmit control information precoded with the uplink precoder to the base station via a PUCCH. In one embodiment, the UE performs the method 800 when the usage parameter in the SRS resource set is set to “nonCodebook.”

[0058] Figure 9 is a block diagram illustrating elements of an apparatus 900 performing wireless communication with a base station 950 according to one embodiment. In one embodiment, the apparatus 900 may be a UE and the base station 950 may be a gNb or the like, both of which may operate in a wireless network, such as the wireless network 100 in Figure 1. In one embodiment, the apparatus 900 may be the UE 150 in Figure 1 and Figure 5. In one embodiment, the base station 950 includes an antenna array 955 to form beams for transmitting and receiving signals.

[0059] As shown, the apparatus 900 may include an antenna assembly 910; e.g., MIMO antenna arrays, to support beamforming operations, and a transceiver circuit (also referred to as a transceiver 920) including a transmitter and a receiver configured to provide radio communications with another station in a radio access network. The transmitter and the receiver may include filters in the digital front end for each cluster, and each filter can be enabled to pass signals and disabled to block signals. The transceiver 920 is operative to receive downlink signals (e.g., a MAC CE) and transmit uplink signals according to methods 700 and 701 in Figures 7A and 7B, respectively. The apparatus 900 may also include processing circuitry 930 which may include one or more control processors, signal processors, central processing units, cores, and/or processor cores. The apparatus 900 may also include a memory circuit (also referred to as memory 940) coupled to the processing circuitry 930. The memory 940 may store configurations for supporting wireless communication, including an SRS resource set configuration 945. The processing circuitry 930 is coupled to the memory 940 and operative to update the SRS resource set configuration according to the received MAC CE. The apparatus 900 may also include an interface (such as a user interface). The apparatus 900 may be incorporated into a wireless system, a station, a terminal, a device, an appliance, a machine, and IoT operable to perform wireless communication in a multi-access network, such as a 5G NR network. It is understood the embodiment of Figure 9 is simplified for illustration purposes. Additional hardware components may be included.

[0060] In one embodiment, the apparatus 900 may store and transmit (internally and/or with other electronic devices over a network) code (composed of software instructions) and data using computer-readable media, such as non-transitory tangible computer-readable media (e.g., computer- readable storage media such as magnetic disks; optical disks; read-only memory; flash memory devices) and transitory computer-readable transmission media (e.g., electrical, optical, acoustical or other forms of propagated signals). For example, the memory 940 may include a non-transitory computer-readable storage medium that stores computer-readable program code. The code, when executed by the processors, causes the processors to perform operations according to embodiments disclosed herein, such as the method disclosed in Figure 7.

[0061] Although the apparatus 900 is used in this disclosure as an example, it is understood that the methodology described herein is applicable to any computing and/or communication device capable of performing wireless communications.

[0062] The operations of the flow diagrams of Figures 7A, 7B and 8 have been described with reference to the exemplary embodiments of Figures 1, 5, and 9. However, it should be understood that the operations of the flow diagrams of Figures 7A, 7B and 8 can be performed by embodiments of the invention other than the embodiments of Figures 1, 5, and 9, and the embodiments of Figures 1, 5, and 9 can perform operations different than those discussed with reference to the flow diagrams. While the flow diagrams of Figures 7A, 7B and 8 show a particular order of operations performed by certain embodiments of the invention, it should be understood that such order is exemplary (e.g., alternative embodiments may perform the operations in a different order, combine certain operations, overlap certain operations, etc.).

[0063] Various functional components or blocks have been described herein. As will be appreciated by persons skilled in the art, the functional blocks will preferably be implemented through circuits (either dedicated circuits, or general-purpose circuits, which operate under the control of one or more processors and coded instructions), which will typically comprise transistors that are configured in such a way as to control the operation of the circuity in accordance with the functions and operations described herein.

[0064] While the invention has been described in terms of several embodiments, those skilled in the art will recognize that the invention is not limited to the embodiments described, and can be practiced with modification and alteration within the spirit and scope of the appended claims. The description is thus to be regarded as illustrative instead of limiting.