WO2025160951A1

WO2025160951A1 - Method for sounding reference signal power scaling

Info

Publication number: WO2025160951A1
Application number: PCT/CN2024/075512
Authority: WO
Inventors: Yushu Zhang; Jia-Hong Liou
Original assignee: Google LLC
Current assignee: Google LLC
Priority date: 2024-02-02
Filing date: 2024-02-02
Publication date: 2025-08-07
Anticipated expiration: 2026-08-02

Abstract

This disclosure provides systems, devices, apparatus, and methods, including computer programs encoded on storage media, for sounding reference signal (SRS) power scaling. A UE 102 receives (304), from a network entity 104, an SRS resource configuration indicating multiple SRS resources at least partially overlapping in a time-domain. The UE 102 transmits (308), to the network entity 104, an SRS from one or more of the multiple SRS resources in a symbol based on a power scaling scheme associated with a respective priority of the multiple SRS resources when a total transmission power exceeds a maximum transmission power in the symbol.

Description

METHOD FOR SOUNDING REFERENCE SIGNAL POWER SCALING

TECHNICAL FIELD

The present disclosure relates generally to wireless communication, and more particularly, to method for sounding reference signal (SRS) power scaling.

BACKGROUND

The Third Generation Partnership Project (3GPP) specifies a radio interface referred to as fifth generation (5G) new radio (NR) (5G NR) . An architecture for a 5G NR wireless communication system includes a 5G core (5GC) network, a 5G radio access network (5G-RAN) , a user equipment (5G UE) , etc. The 5G NR architecture seeks to provide increased data rates, decreased latency, and/or increased capacity compared to prior generation cellular communication systems.

Wireless communication systems, in general, provide various telecommunication services (e.g., telephony, video, data, messaging, etc. ) based on multiple-access technologies, such as orthogonal frequency division multiple access (OFDMA) technologies, that support communication with multiple UEs. Improvements in mobile broadband continue the progression of such wireless communication technologies. For example, power scaling operations may be performed when the total user equipment (UE) transmission power for the uplink exceeds the maximum transmission power. The maximum transmission power may be determined by the UE and/or configured by the network entity. The total UE transmission power in a symbol of a slot is defined as the sum of the linear values of transmission powers for physical uplink shared channel (PUSCH) , physical uplink control channel (PUCCH) , physical random access channel (PRACH) , and sounding reference signal (SRS) in the symbol of the slot. When the sum exceeds the maximum transmission power in the symbol of the slot, the UE may perform the power scaling operation based on priority rules associated the uplink channels/signals. However, the priority rules for the power scaling operation for multiple SRS resources configured with the same time-domain behavior have not been defined.

BRIEF SUMMARY

The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects. This summary neither identifies key or critical elements of all aspects nor delineates the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

A user equipment (UE) uses sounding reference signal (SRS) for uplink channel sounding, including channel quality estimation, and synchronization. Currently, a network entity can configure multiple SRS resources in one SRS resource set or in different SRS resource sets for different usages, such as codebook based transmission, non-codebook based transmission, beam management, or antenna switching. The network entity can configure the usage of the SRS resource set (s) based on radio resource control (RRC) parameter usage.

Additionally, the network entity may configure the multiple SRS resources with the same time-domain behavior, such as, aperiodic, periodic, or semi-persistent. Accordingly, the UE may be scheduled to transmit SRS on multiple configured SRS resources in one SRS resource set or in different SRS resource sets at overlapped symbols. In some examples, the UE may be scheduled with multiple SRS resources in one SRS resource set for codebook based transmission or non-codebook based transmission in one symbol. In some examples, the UE may be scheduled with multiple SRS resources in different SRS resource sets for beam management, codebook based transmission, non-codebook based transmission, or antenna switching in one symbol. In other examples, the UE may be scheduled with multiple SRS resources in different SRS resource sets based on different usages at the overlapped symbols. In some other examples, the UE may be scheduled with SRS resources for codebook and beam management in overlapped symbols.

Power scaling operations may be performed when the total UE transmission power for the uplink exceeds the maximum transmission power. The maximum transmission power may be determined by the UE and/or configured by the network entity. The total UE transmission power in a symbol of a slot is defined as the sum of the linear values of transmission powers for physical uplink shared channel (PUSCH) , physical uplink control channel (PUCCH) , physical random access channel (PRACH) , and SRS in the symbol of the slot. When the sum exceeds the maximum transmission power in the symbol of the slot, the UE may perform the power scaling operation based on priority rules associated the uplink channels/signals. However, the priority rules for the power scaling operation for multiple SRS resources configured with the same time-domain behavior have not been defined.

Aspects of the present disclosure address the above-noted and other deficiencies by implementing techniques for the SRS power scaling operation based on configured SRS resources. In some examples, the network entity transmits an SRS resource configuration indicating configured SRS resources and, optionally, a power scaling scheme. The power scaling operation may be performed when a total uplink transmission power in a symbol exceeds a maximum transmission power for the symbol. The power scaling scheme may be based on the configured SRS resources. In some examples, the configured SRS resources are a part of a same resource set. In some other examples, the configured SRS resources are a part of different resource sets.

According to some aspects, a UE receives, from a network entity, an SRS resource configuration indicating multiple SRS resources at least partially overlapping in a time-domain. The UE transmits, to the network entity, an SRS from one or more of the multiple SRS resources in a symbol based on a power scaling scheme associated with a respective priority of the multiple SRS resources when a total transmission power exceeds a maximum transmission power in the symbol.

According to some aspects, a network entity transmitting, to a UE, a sounding reference signal, SRS, resource configuration indicating multiple SRS resources at least partially overlapping in a time-domain. The network entity receives, from the UE, an SRS from one or more of the multiple SRS resources in a symbol based on a power scaling scheme associated with a respective priority of the multiple SRS resources when a total transmission power exceeds a maximum transmission power in the symbol.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a diagram of a wireless communications system that includes a plurality of user equipments (UEs) and network entities in communication over one or more cells according to an embodiment.

FIG. 2 illustrates an example technique for uplink power scaling according to an embodiment.

FIG. 3 illustrates a signaling diagram illustrating communications between a user equipment (UE) and a network entity for the sounding reference signal (SRS) power scaling technique according to an embodiment.

FIG. 4 illustrates an example for the power scaling factor for all SRS resources in the overlapped symbol to maintain the same transmission power for each SRS resource according to an embodiment.

FIG. 5 illustrates an example for the equal power scaling factor for all SRS subcarriers for all SRS resources in the overlapped symbol according to an embodiment.

FIG. 6 illustrates an example for the power scaling factor for the SRS resources in the overlapped symbol to maintain the same transmission power per resource element (RE) per port according to an embodiment.

FIG. 7 illustrates an example for the power scaling for the SRS resources with lower priority according to an embodiment.

FIG. 8 illustrates an example for the procedure of a dynamic power scaling operation selection according to an embodiment.

FIG. 9 illustrates an example for the SRS transmission based on the power scaling indication according to an embodiment.

FIG. 10 illustrates an example for the associated SRS determination based on the SRS without power scaling for the physical uplink shared channel (PUSCH) transmission according to an embodiment.

FIG. 11 is a flowchart of a method of wireless communication at a UE according to an embodiment.

FIG. 12 is a flowchart of a method of wireless communication at a network entity according to an embodiment.

FIG. 13 is a diagram illustrating a hardware implementation for an example UE apparatus according to some embodiments.

FIG. 14 is a diagram illustrating a hardware implementation for one or more example network entities according to some embodiments.

DETAILED DESCRIPTION

FIG. 1 illustrates a diagram 100 of a wireless communications system associated with a plurality of cells 190. The wireless communications system includes user equipments (UEs) 102 and base stations/network entities 104. Some base stations may include an aggregated base station architecture and other base stations may include a disaggregated base station architecture. The aggregated base station architecture utilizes a radio protocol stack that is physically or logically integrated within a single radio access network (RAN) node. A disaggregated base station architecture utilizes a protocol stack that is physically or logically distributed among two or more units (e.g., radio unit (RU) 106, distributed unit (DU) 108, central unit (CU) 110) . For example, a CU 110 is implemented within a RAN node, and one or more DUs 108 may be co-located with the CU 110, or alternatively, may be geographically or virtually distributed throughout one or multiple other RAN nodes. The DUs 108 may be implemented to communicate with one or more RUs 106. Any of the RU 106, the DU 108 and the CU 110 can be implemented as virtual units, such as a virtual radio unit (VRU) , a virtual distributed unit (VDU) , or a virtual central unit (VCU) . The base station/network entity 104 (e.g., an aggregated base station or disaggregated units of the base station, such as the RU 106 or the DU 108) , may be referred to as a transmission reception point (TRP) .

Operations of the base station 104 and/or network designs may be based on aggregation characteristics of base station functionality. For example, disaggregated base station architectures are 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 a cloud radio access network (C-RAN) . Disaggregation may include distributing functionality across the two or more units at various physical locations, as well as distributing functionality for at least one unit virtually, which can enable flexibility in network designs. The various units of the disaggregated base station architecture, or the disaggregated RAN architecture, can be configured for wired or wireless communication with at least one other unit. For example, the base stations 104d, 104e and/or the RUs 106a, 106b, 106c, 106d may communicate with the UEs 102a, 102b, 102c, 102d, and/or 102s via one or more radio frequency (RF) access links based on a Uu interface. In examples, multiple RUs 106 and/or base stations 104 may simultaneously serve the UEs 102, such as by intra-cell and/or inter-cell access links between the UEs 102 and the RUs 106/base stations 104.

The RU 106, the DU 108, and the CU 110 may include (or may be coupled to) one or more interfaces configured to transmit or receive information/signals via a wired or wireless transmission medium. For example, a wired interface can be configured to transmit or receive the information/signals over a wired transmission medium, such as via the fronthaul link 160 between the RU 106d and the baseband unit (BBU) 112 of the base station 104d associated with the cell 190d. The BBU 112 includes a DU 108 and a CU 110, which may also have a wired interface (e.g., midhaul link) configured between the DU 108 and the CU 110 to transmit or receive the information/signals between the DU 108 and the CU 110. In further examples, a wireless interface, which may include a receiver, a transmitter, or a transceiver, such as an RF transceiver, configured to transmit and/or receive the information/signals via the wireless transmission medium, such as for information communicated between the RU 106a of the cell 190a and the base station 104e of the cell 190e via cross-cell communication beams 136-138 of the RU 106a and the base station 104e.

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

The RUs 106 may transmit or receive over-the-air (OTA) communication 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 a first set of communication beams 132 of the RU 106b and a second set of communication beams 134b of the UE 102b, which may correspond to inter-cell communication beams or, in some examples, cross-cell communication beams. For instance, the UE 102b of the cell 190b may communicate with the RU 106a of the cell 190a via a third set of communication beams 134a of the UE 102b and a fourth set of communication beams 136 of the RU 106a. DUs 108 can control both real-time and non-real-time features of control plane and user plane communications of the RUs 106.

Any combination of the RU 106, the DU 108, and the CU 110, or reference thereto individually, may correspond to a base station 104. Thus, the base station 104 may include at least one of the RU 106, the DU 108, or the CU 110. The base stations 104 provide the UEs 102 with access to a core network. The base stations 104 may relay communications between the UEs 102 and the core network (not shown) . The base stations 104 may be associated with macrocells for higher-power cellular base stations and/or small cells for lower-power cellular base stations. For example, the cell 190e may correspond to a macrocell, whereas the cells 190a-190d may correspond to small cells. Small cells include femtocells, picocells, microcells, etc. A network that includes at least one macrocell and at least one small cell may be referred to as a “heterogeneous network. ”

Transmissions from a UE 102 to a base station 104/RU 106 are referred to as uplink (UL) transmissions, whereas 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 and downlink transmissions may also be referred to as forward link transmissions. For example, the RU 106d utilizes antennas of the base station 104d of cell 190d to transmit a downlink/forward link communication to the UE 102d or receive an uplink/reverse link communication from the UE 102d based on the Uu interface associated with the access link between the UE 102d and the base station 104d/RU 106d.

Communication links between the UEs 102 and the base stations 104/RUs 106 may be based on multiple-input and multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and/or transmit diversity. The communication links may be associated with one or more carriers. The UEs 102 and the base stations 104/RUs 106 may utilize a spectrum bandwidth of Y MHz (e.g., 5, 10, 15, 20, 100, 400, 800, 1600, 2000, etc. MHz) per carrier allocated in a carrier aggregation of up to a total of Yx MHz, where x component carriers (CCs) are used for communication in each of the uplink and downlink directions. The carriers may or may not be adjacent to each other along a frequency spectrum. In examples, uplink and downlink carriers may be allocated in an asymmetric manner, with more or fewer carriers allocated to either the uplink or the downlink. A primary component carrier and one or more secondary component carriers may be included in the component carriers. The primary component carrier may be associated with a primary cell (PCell) and a secondary component carrier may be associated with a secondary cell (SCell) .

Some UEs 102, such as the UEs 102a and 102s, may perform device-to-device (D2D) communications over sidelink. For example, a sidelink communication/D2D link utilizes a spectrum for a wireless wide area network (WWAN) associated with uplink and downlink communications. Such sidelink/D2D communication may be performed through various wireless communications systems, such as wireless fidelity (Wi-Fi) systems, Bluetooth systems, Long Term Evolution (LTE) systems, New Radio (NR) systems, etc.

The UEs 102 and the base stations 104/RUs 106 may each include a plurality of antennas. The plurality of antennas may correspond to antenna elements, antenna panels, and/or antenna arrays that may facilitate beamforming operations. For example, the RU 106b transmits a downlink beamformed signal based on a first set of communication beams 132 to the UE 102b in one or more transmit directions of the RU 106b. The UE 102b may receive the downlink beamformed signal based on a second set of communication beams 134b from the RU 106b in one or more receive directions of the UE 102b. In a further example, the UE 102b may also transmit an uplink beamformed signal (e.g., sounding reference signal (SRS) ) to the RU 106b based on the second set of communication beams 134b in one or more transmit directions of the UE 102b. The RU 106b may receive the uplink beamformed signal from the UE 102b in one or more receive directions of the RU 106b. The UE 102b may perform beam training to determine the best receive and transmit directions for the beamformed signals. The transmit and receive directions for the UEs 102 and the base stations 104/RUs 106 may or may not be the same.

In further examples, beamformed signals may be communicated between a first base station/RU 106a and a second base station 104e. For instance, the base station 104e of the cell 190e may transmit a beamformed signal to the RU 106a based on the communication beams 138 in one or more transmit directions of the base station 104e. The RU 106a may receive the beamformed signal from the base station 104e of the cell 190e based on the RU communication beams 136 in one or more receive directions of the RU 106a. In further examples, the base station 104e transmits a downlink beamformed signal to the UE 102e based on the communication beams 138 in one or more transmit directions of the base station 104e. The UE 102e receives the downlink beamformed signal from the base station 104e based on UE communication beams 130 in one or more receive directions of the UE 102e. The UE 102e may also transmit an uplink beamformed signal to the base station 104e based on the UE communication beams 130 in one or more transmit directions of the UE 102e, such that the base station 104e may receive the uplink beamformed signal from the UE 102e in one or more receive directions of the base station 104e.

The base station 104 may include and/or be referred to as a network entity. That is, “network entity” may refer to the base station 104 or at least one unit of the base station 104, such as the RU 106, the DU 108, and/or the CU 110. The base station 104 may also include and/or be referred to as a next generation evolved Node B (ng-eNB) , a next 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 TRP, a network node, network equipment, or other related terminology. The base station 104 or an entity at the base station 104 can be implemented as an IAB node, a relay node, a sidelink node, an aggregated (monolithic) base station, or a disaggregated base station including one or more RUs 106, DUs 108, and/or CUs 110. A set of aggregated or disaggregated base stations may be referred to as a next generation-radio access network (NG-RAN) . In some examples, the UE 102a operates in dual connectivity (DC) with the base station 104e and the base station/RU 106a. In such cases, the base station 104e can be a master node and the base station/RU 106a can be a secondary node.

Still referring to FIG. 1, in certain aspects, any of the UEs 102 may include a UE SRS Power Scaling component 140 configured to receive, from a network entity, an SRS resource configuration indicating multiple SRS resources at least partially overlapping in a time-domain; transmit, to the network entity, an SRS from one or more of the multiple SRS resources in a symbol based on a power scaling scheme associated with a respective priority of the multiple SRS resources when a total transmission power exceeds a maximum transmission power in the symbol.

In certain aspects, any of the base stations 104 or a network entity of the base stations 104 may include a network entity SRS Power Scaling component 150 configured to transmit, to a UE, a sounding reference signal, SRS, resource configuration indicating multiple SRS resources at least partially overlapping in a time-domain; receive, from the UE, an SRS from one or more of the multiple SRS resources in a symbol based on a power scaling scheme associated with a respective priority of the multiple SRS resources when a total transmission power exceeds a maximum transmission power in the symbol.

Accordingly, FIG. 1 describes a wireless communication system that may be implemented in connection with aspects of one or more other figures described herein. Further, although the following description may be focused on 5G NR, the concepts described herein may be applicable to other similar areas, such as 5G- Advanced and future versions, LTE, LTE-advanced (LTE-A) , and other wireless technologies, such as 6G.

The network entity can configure SRS resource sets with different usages, and the network entity can configure the usage of each SRS resource set based on the radio resource control (RRC) parameter usage as shown below. When the network entity configures the RRC parameter usage for the SRS resource set as ‘codebook’ , the UE transmits the SRS resources in the SRS resource set for the network entity to perform uplink channel state information (CSI) measurement. The network entity may measure the uplink CSI based on such SRS resources and identify the modulation and coding scheme (MCS) and the precoder for the physical uplink shared channel (PUSCH) based on a predefined codebook.

When the network entity configures the RRC parameter usage for the SRS resource set as ‘nonCodebook’ , the UE may transmit the 1-port SRS resources in the SRS resource set based on a precoder determined by the UE (UE-determined) . The UE may transmit different layers of the UE-determined precoder by different SRS resources. The UE may determine the precoder based on a CSI reference signal (CSI-RS) associated with the SRS resource set. The network entity may measure the uplink CSI based on the SRS resources and identify the MCS and rank N precoder for the PUSCH based on N SRS resources from all the SRS resources in the SRS resource set.

When the network entity configures the RRC parameter usage for the SRS resource set as ‘antennaSwitching’ , the UE may transmit the SRS resources with different UE antenna ports. For example, for a UE with x transmission antenna ports and y receiving antenna ports (xTyR) , the network entity may configure an SRS resource set with (y/x) resources and configures the UE to transmit the SRS from x ports for each SRS resource. The network entity configures the time domain location of the SRS resources based on a minimum guard period (GP) , which is predefined based on the subcarrier spacing of the SRS.

When the network entity configures the RRC parameter usage for the SRS resource set as ‘beamMangement’ , the UE may transmit different SRS resources in the SRS resource set based on different transmission beams (spatial domain filters) . The network entity may identify the best beam based on the measurement of the SRS resources.

FIG. 2 illustrates an example technique 200 for uplink power scaling according to an embodiment.

Referring to FIG. 2, for an uplink transmission, when the total transmission power exceeds the maximum transmission power 202 in a symbol, the UE may perform a power scaling for the uplink signals with the lowest priority.

An UL scheduling status 220 indicates an UL signal 1 204 and an UL signal 2 206. As shown, the SRS resources for the UL signal 1 204 and the UL signal 2 206 are at least partially overlapping in a time-domain. Here, the priority of the UL signal 2 206 is lower than that of the signal 1 204. Accordingly, as illustrated in FIG. 2, an UL transmission status 222 shows that the UE performs a power scaling for the UL signal 2 206 when it is determined that the total transmission power exceeds the maximum transmission power 202 in a symbol. The total UE transmit power in a symbol of a slot is defined as the sum of the linear values of the UE transmit powers for the PUSCH, the PUCCH, the PRACH, and the SRS in the symbol of the slot. The UE may determine the total UE transmit power in a symbol of a slot based on the uplink signals per UE panel, e.g., uplink signals corresponding to a TCI state or associated with an SRS resource set or a downlink reference signal or an identifier configured by the network entity, or across all UE panels. The maximum transmission power may be determined by the UE and/or configured by the network entity (e.g., defined in section 8-1 of the 3GPP technical specification (TS) 38.101-1 for the frequency range (FR) 1 and section 8-2 of the 3GPP TS 38.101-2 for the FR2) . The UE may determine maximum transmission power per UE panel or across all UE panels. In one example, the priority order (in a descending order) is defined as follows: (1) a PRACH transmission on a candidate cell, if any, as described in Clause 21 of the 3GPP TS 38.213; (2) a PRACH transmission on the PCell; (3) PUCCH or PUSCH transmissions with a higher priority index; (4) PUCCH or PUSCH transmissions with same priority index, (a) a PUCCH transmission with a hybrid automatic repeat request-acknowledgement (HARQ-ACK) information, and/or a scheduling request (SR) , and/or a link recovery request (LRR) , or a PUSCH transmission with a HARQ-ACK information of the priority index, (b) a PUCCH transmission with a CSI or a PUSCH transmission with a CSI, (c) a PUSCH transmission without a HARQ-ACK information of the priority index or a CSI and, for a Type-2 random access procedure, a PUSCH transmission on the PCell; (5) if the UE is configured with prioSCellPRACH-OverSP- PeriodicSRS-r17, (a) an aperiodic SRS transmission or a PRACH transmission on a serving cell other than the PCell, a semi-persistent and/or a periodic SRS transmission; (6) otherwise, an SRS transmission, with an aperiodic SRS having a higher priority than a semi-persistent and/or a periodic SRS, or a PRACH transmission on a serving cell other than the PCell.

In a situation of the same priority order and for an operation with carrier aggregation, the UE prioritizes the power allocation for transmissions on the primary cell of the master cell group (MCG) or the secondary cell group (SCG) over transmissions on a secondary cell. In a situation of the same priority order and for an operation with two UL carriers, the UE prioritizes the power allocation for transmissions on the carrier where the UE is configured to transmit the PUCCH. If the PUCCH is not configured for any of the two UL carriers, the UE prioritizes the power allocation for the transmissions on the non-supplementary UL carrier.

FIG. 3 is a signaling diagram 300 illustrating communications between a UE 102 and a network entity 104 for SRS transmission uplink power scaling technique according to an embodiment. The network entity 104 may correspond to a base station or a unit of a base station, such as the RU 106, the DU 108, the CU 110, etc.

In some implementations, the UE may optionally transmit 302, to the network entity (the network entity may receive, from the UE) , UE capability report indicating the supported SRS transmission power scaling operation for SRS resources in an SRS resource set and/or SRS resources in different SRS resource sets. In some aspects, the UE capability report may include at least one of the information: whether the UE supports common power scaling factor for each SRS resource; whether the UE supports common scaled transmission power for each resource element (RE) or resource block (RB) for each SRS resource; whether the UE supports overlapped SRS resources with different bandwidth; whether the UE supports overlapped SRS resources with different number of subcarriers; whether the UE supports partially overlapped SRS resources in time domain; whether the UE supports power scaling or dropping of overlapped SRS resources when the UE determines to perform power scaling for the SRS resource (s) .

Based on the UE capability report, the network entity transmits 304 (the UE receives from the network entity) an RRC signaling configuring at least one of the parameters: SRS resources in an SRS resource set with partially or fully overlapped symbol (s) ; SRS resources in different SRS resource sets with partially or fully overlapped symbol (s) . The network entity may optionally configure SRS power scaling operation for SRS resources in an SRS resource set and/or SRS resources in different SRS resource sets, e.g., equal power scaling or non-equal power scaling or dropping of the SRS resource (s) with lower priority.

For a semi-persistent SRS resource set, the network entity may optionally transmit 310 a medium access control (MAC) control element activating the SRS resource set. For an aperiodic SRS resource set, the network entity may transmit a downlink control information (DCI) triggering the SRS resource set. To activate or trigger multiple SRS resource sets, the network entity may transmit one or multiple MAC CEs or DCIs. The network entity may indicate the SRS power scaling operation for the activated or triggered SRS resource set (s) by the MAC CE or DCI.

Then, the UE determines the transmission power for each SRS resource in the SRS resource set (s) based on power control parameters, e.g., target received power (P0) , pathloss compensation factor (alpha) , pathloss measured from a pathloss reference signal, a closed-loop power adjustment factor or state. The UE may receive the configuration of the power control parameters by RRC signaling, MAC CE, or DCI. In some examples, the UE may receive the configuration of the power control parameters based on the transmission configuration indicator (TCI) state configured or indicated by the network entity for the SRS resource.

In some implementations, for each SRS resource, the UE may determine the transmission power based on power control equation in 3GPP TS 38.213 section 7.3.1. When the total transmission power for the uplink signals exceeds the maximum transmission power in a symbol, the UE may determine to perform power scaling for one or multiple SRS resources in the symbol.

Then the UE transmits 308 the SRS resource (s) in the SRS resource set (s) based on the scaled transmission power. If the UE determines different transmission power for different symbols for an SRS resource after the power scaling, the UE may transmit SRS on a symbol for the SRS resource based on the determined transmission power corresponding to the symbol. Alternatively, if the UE determines different transmission power for different symbols for an SRS resource after the power scaling, the UE may transmit SRS on all the symbols for the SRS resource based on a common transmission power. The UE may determine the common transmission power based on the minimum, maximum, or average determined transmission power corresponding to each symbol.

In some implementations, after receiving the SRS for codebook or non-codebook based transmission, the network entity may optionally transmit 310 a DCI scheduling PUSCH, and may indicate one or multiple SRS resources in the one or multiple SRS resource set (s) to be associated with the PUSCH.

The UE may transmit 312 the PUSCH based on the power scaling factors for the associated SRS resources.

In this disclosure, unless specified, a RRC signaling may indicate a RRC reconfiguration message from the network entity to UE, or a System Information Block (SIB) , where the SIB can be an existing SIB (e.g., SIB1) or a new SIB (e.g., SIB J, where J is an integer above 21) transmitted by the network entity. In some implementations, the network entity may receive the UE capability from a UE or from a core network (e.g., Access and Mobility Management Function (AMF) ) or another network entity.

In an embodiment, the UE may report one of the following UE capabilities: the UE supports the simultaneous transmission of SRS resources in a SRS resource set, the maximum number of SRS resources in an SRS resource set for simultaneous transmission; the maximum number of SRS ports across the SRS resources in an SRS resource set for simultaneous transmission. The UE may report the one or multiple UE capabilities for one or multiple usages separately or commonly.

In some examples, the network entity may configure multiple or all the SRS resources in an SRS resource set for the non-codebook in overlapped symbol (s) . In some other examples, the network entity may configure X SRS resources in an SRS resource subset or an SRS resource set for a codebook in overlapped symbol (s) , where the UE transmits the X SRS resources from different antenna ports and the total number of antenna ports across the X SRS resources is smaller than or equal to the maximum number of SRS ports that the UE reported.

In an embodiment, if the UE determines to perform a power scaling for the SRS resources in an SRS resource set in a symbol when the total uplink transmission power in the symbol exceeds the maximum transmission power, the UE may perform the power scaling for the SRS resources in the SRS resource set to maintain the same transmission power for each SRS resource. Thus, the UE may transmit the SRS resources in the overlapped symbol (s) based on the same transmission power.

FIG. 4 illustrates an example of a power scaling operation 400 for the power scaling factor for all SRS resources in the overlapped symbol to maintain the same transmission power for each SRS resource according to an embodiment. Referring to FIG. 4, the maximum transmission power 402 is configured for the UL scheduling status 420 and the UL transmission status 422. The UE determines to perform power scaling for the SRS resources 408 and 410 in a symbol when the total uplink transmission power (as shown in the UL scheduling status 420) in the symbol exceeds the maximum transmission power 402. As shown, the UE performs the power scaling for the SRS resource 1 408 and the SRS resource 2 410 in the SRS resource set to maintain a same transmission power for each SRS resource as shown in the UL transmission status 422.

The UL scheduling status 420 illustrates SRS resource 1 408 is scheduled to be transmitted at a transmission power 404 and SRS resource 2 410 is scheduled to be transmitted at a transmission power 406. The UE determines to perform power scaling because the total transmission power in a symbol (e.g., transmission power 404 + transmission power 406) is greater than the maximum transmission power 402.

The UL transmission status 422 illustrates transmission of the SRS resource 1 408 and SRS resource 2 410 after a power scaling operation performed by the UE. The power scaling 412 (X1 mW) is performed on SRS resource 1 408 and power scaling 414 (X2 mW) is performed on SRS resource 1 410 such that the SRS resource 1 408 and SRS resource 2 410 are transmitted at a same transmission power (as shown in UL transmission status 422) . Note that although FIG. 4 only shows two SRS resources, a greater number of SRS resources may also be used in an SRS resource set or different SRS resource sets.

The UE may determine the transmission power based on the number of overlapped SRS resources in the overlapped symbol, and the total maximum uplink transmission power for the SRS resources in the overlapped symbol.

The UE may determine the total maximum uplink transmission power for the SRS resources based on the total transmission power for other uplink signal in the overlapped symbol with higher priority than the SRS, the maximum uplink transmission power for the transmission occasion and the number of overlapped SRS resources in the SRS resource set. The UE may keep the same transmission power for each SRS resource after power scaling.

In some examples, the UE may determine the transmission power in the dBm for one SRS resource in the symbol l’ in bandwidth part (BWP) b, carrier f, serving cell c according to the equation 1 (if P_cmax (i) -P_total (l′) >0) :

Where K_l′ indicates the number of overlapped SRS resources in the SRS resource set for power scaling in the overlapped symbol l’; P_cmax (i) is the linear maximum transmission power for transmission occasion i as defined in the section 8-1 of the 3GPP TS 38.101-1 for a FR 1 and the section 8-2 of the 3GPP TS 38.101-2 for a FR2; P_total (l′) is the total linear transmission power of the uplink signals with higher priority than the SRS resource set for power scaling on the serving cells in one frequency range. If the P_cmax (i) -P_total (l′) ≤0, the UE drops the SRS resource set.

In some implementations, if the transmission power for an SRS resource is smaller than a minimum transmission power, the UE may drop the SRS. The minimum transmission power may be predefined or configured by the network entity or reported by the UE.

In some implementations, the UE may determine the minimum transmission power based on a minimum uplink reception power per resource element (RE) or per resource block (RB) , the number of REs or RBs in a symbol for the SRS resource and the pathloss measured from the pathloss reference signal for uplink power control for the SRS. The minimum uplink reception power per RE or per RB may be configured by the network entity or pre-defined. Alternatively, the minimum uplink reception power may be determined based on the target reception power (P0) minus an offset predefined or configured by the network entity.

In some examples, the UE may determine the minimum transmission power according to equation 2.

whereindicates the minimum uplink reception power per RE for an SRS resource; N_{RE, SRS, b, f, c} (i) indicates the number of REs in one symbol for the SRS resource; PL_b, f, c (q_d) indicates the pathloss that the UE obtained from a pathloss reference signal q_d based on the transmission power the network entity configured for the pathloss reference signal and measured filtered reference signal reception power (RSRP) for the pathloss reference signal.

In some implementations, the network entity may provide the same configuration for at least one of the followings for the overlapped SRS resources in the SRS resource set: number of subcarriers, subcarriers, bandwidth (e.g., number of RBs) , allocated RBs, symbol index within a slot, and number of ports. Thus, the network entity may refrain from configuring the overlapped SRS resources in the SRS resource set with different configuration for at least one of the above-describe parameters. The UE may expect the network entity to provide the same configuration for at least one of the above-describe parameters.

In an embodiment, if the UE determines to perform power scaling for the SRS resources in an SRS resource set in a symbol when the total uplink transmission power in the symbol exceeds the maximum transmission power, the UE may perform an equal power scaling for all the SRS resources in the SRS resource set in the symbol.

FIG. 5 illustrates an example power scaling operation 500 for the equal power scaling factor for all SRS subcarriers for all SRS resources in the overlapped symbol according to an embodiment. Referring to FIG. 5, the maximum transmission power 502 is configured for the UL scheduling status 520 and the UL transmission status 522. The UE determines to perform power scaling for the SRS resource 1 508 and SRS resource 2 510 in a symbol when the total uplink transmission power (as shown in the UL scheduling status 520) in the symbol exceeds the maximum transmission power 502.

The UL scheduling status 520 illustrates an SRS resource 1 508 is scheduled to be transmitted at transmission power 504 and SRS resource 2 510 is scheduled to be transmitted at transmission power 506. The UE determines to perform power scaling because a total transmission power (e.g., transmission power 504 + transmission power 506) in a symbol exceeds the maximum transmission power 502.

The UL transmission status 522 illustrates transmission of the SRS resource 1 508 and SRS resource 2 510 after a power scaling operation performed by the UE. The transmission power for SRS resource 1 508 is indicated as transmission power 512. The transmission power for SRS resource 2 510 is indicated as transmission power 514. As shown, the power scaling for each SRS resource is applied by the same amount (X mW) . Thus, there is an equal power split per SRS resource (i.e., equal power scaling factor for all SRS subcarriers for all SRS resources in the overlapped symbol) .

As described above, although FIG. 5 only shows two SRS resources, a greater number of SRS resources may also be used in an SRS resource set or different SRS resource sets. When UE performs equal power scaling, UE may use the same power scaling or power reduction factor or value.

Thus, the UE may determine the power scaling factor based on the total transmission power for other uplink signal in the overlapped symbol with a higher priority than the SRS, the maximum uplink transmission power for the transmission occasion, the total target uplink transmission power for the SRS resources in the overlapped symbol based on the power control parameters and the number of overlapped SRS resources in the SRS resource set. The UE may keep the same transmission power for each subcarrier or RE for each SRS resource after power scaling in the overlapped symbol. Thus, the UE may transmit the SRS on the SRS resources in the overlapped symbol based on the same transmission power per RE.

FIG. 5 is one example for the equal power scaling factor for all SRS subcarriers for all SRS resources in the overlapped symbol.

In some examples, the UE may determine the transmission power in dBm for one SRS resource in the symbol l’ in bandwidth part (BWP) b, carrier f, serving cell c according to equation 3 (if P_cmax (i) -P_total (l′) >0) :

where K_l′ indicates the number of the overlapped SRS resources in the overlapped symbol l’; is the linear value of P_{SRS, b, f, c} (i, q_s, l) which indicates the transmission power determined by the UE for transmission occasion i of the SRS resource based on the power control parameters set q_s, and closed-loop power adjustment state l according to 3GPP TS 38.213 section 7.3.1 or P_{SRS, b, f, c} (i, q_s, l) may be determined according to equation 4 or equation 5 alternatively; P_total, SRS (l′) indicates the total linear uplink transmission power for the overlapped SRS resources in the overlapped symbol l’ based on the uplink power control parameters.

Where P_CMAX, f, c (i) is the UE configured maximum output power; is the target received power per RE; u indicates the subcarrier scaling factor defined in the 3GPP TS 38.211; N_{RE, SRS, b, f, c} (i) is the number of REs in a symbol for the SRS resource; α_{SRS, b, f, c} (q_s) is the pathloss compensation factor; PL_b, f, c (q_d) is the pathloss measured from a pathloss reference signal; h_b, f, c (i, l) is the closed-loop power adjustment state.

Whereis the target received power per RB based on a reference number of SRS REs per RB; N_RPFis the scaling factor based on the configured number of SRS REs per RB and the reference number of SRS REs. In some examples, whereindicates the reference number of SRS REs per RB andindicates the configured number of SRS REs per RB.

Alternatively, the UE may determine the maximum total transmission power for the overlapped SRS resources based on the maximum transmission power and transmission power for other uplink signals with higher priority than the SRS, and then allocate the transmission power for each RE equally across the overlapped SRS resources based on the maximum total transmission power for the overlapped SRS resources. In some examples, the UE may determine the transmission power for each SRS resources as follows:

Where N_{RE, total, SRS, b, f, c} (l′) indicates the total number of REs for the SRS symbol.

In some implementations, if the transmission power for an SRS resource is smaller than a minimum transmission power, the UE may drop the SRS. The minimum transmission power may be predefined or configured by the network entity or reported by the UE. In some examples, the UE may determine the minimum transmission power according to the equation 2.

In some implementations, the network entity may configure the same number of ports for the overlapped SRS resources. Thus, the network entity may refrain from configuring the overlapped SRS resources in the SRS resource set with different number of ports. The UE may expect the network entity should configure the same number of ports for the overlapped SRS resources.

In an embodiment, if the UE determines to perform power scaling for the SRS resources in an SRS resource set in a symbol when the total uplink transmission power in the symbol exceeds the maximum transmission power, the UE may perform the power scaling for the SRS resources to maintain the same transmission power for each RE per port for each SRS resource in the SRS resource set. The UE may perform the power scaling to maintain the same transmission power for all ports across all REs across all SRS resource (s) in the SRS resource set in an overlapped symbol. Thus, the UE may transmit the SRS on the SRS resources in the overlapped symbol based on the same transmission power per RE and per port.

FIG. 6 illustrates an example of a power scaling operation 600 for the power scaling factor for the SRS resources in the overlapped symbol to maintain the same transmission power per RE per port.

The UL scheduling status 620 illustrates an SRS resource 1 608 is scheduled to be transmitted at a transmission power 604 and SRS resource 2 610 is scheduled to be transmitted at a transmission power 606. As shown, SRS resource 1 608 is configured with Z antenna port and SRS resource 2 610 is configured with 2Z antenna port. The UE determines to perform power scaling when the total transmission power in a symbol (e.g., transmission power 604 + transmission power 606) is greater than the maximum transmission power 602.

The UL transmission status 622 illustrates transmission of the SRS resource 1 608 and SRS resource 2 610 after a power scaling operation performed by the UE. As shown, the power scaling X3 mW is performed to the SRS resource 1 608 configured with Z antenna port. The power scaling X4 mW is performed to the SRS resource 2 610 configured with 2Z antenna port. The power scaling as described above causes the same transmission power to be maintained for each RE per port for each SRS resource in the SRS resource set. In other words, the UE may perform the power scaling to maintain the same transmission power for all antenna ports across all REs and across all SRS resources in the SRS resource set in an overlapped symbol. As described above, note that although FIG. 6 only shows two SRS resources, a greater number of SRS resources may also be used in an SRS resource set or different SRS resource sets.

Thus, the UE may determine the power scaling factor based on the total transmission power for other uplink signal in the overlapped symbol with higher priority than the SRS, the maximum uplink transmission power for the transmission occasion, the total target uplink transmission power for the SRS resources in the overlapped symbol based on the power control parameters and the number of ports for each overlapped SRS resource. The UE may keep the same transmission power for each RE per port for each SRS resource after power scaling. Thus, the UE may transmit the SRS on the SRS resources in the overlapped symbol based on the same transmission power for each RE per port.

In some examples, the UE may determine the transmission power in dBm for one SRS resource in the symbol l’ in bandwidth part (BWP) b, carrier f, serving cell c according to equation 7 (if P_cmax (i) -P_total (l′) >0) :

Where N_p indicates the number of ports for the SRS resource; N_p, total indicates the total number of ports for the SRS resources in the overlapped symbol l’.

Alternatively, the UE may determine the maximum total transmission power for the overlapped SRS resources based on the maximum transmission power and transmission power for other uplink signals with higher priority than the SRS, and then allocate the transmission power for each RE per port across the overlapped SRS resources equally based on the maximum total transmission power for the overlapped SRS resources. In some examples, the UE may determine the transmission power for each SRS resources as follows:

In an embodiment, if the UE determines to perform power scaling for the SRS resources in an SRS resource set in a symbol when the total uplink transmission power in the symbol exceeds the maximum transmission power, the UE may perform the power scaling for the SRS resources in the SRS resource set with lowest priority until the total transmission power in the frequency range is below or equal to the maximum transmission power.

FIG. 7 illustrates an example of a power scaling operation 700 for the power scaling for the SRS resources with lower priority according to an embodiment.

The UL scheduling status 720 illustrates an SRS resource 1 708 is scheduled to be transmitted at a transmission power 704 and SRS resource 2 710 is scheduled to be transmitted at a transmission power 706. The UE determines to perform power scaling because the total transmission power in a symbol (e.g., transmission power 704 + transmission power 706) is greater than the maximum transmission power 702.

The UL transmission status 722 illustrates transmission of the SRS resource 1 708 and SRS resource 2 710 after a power scaling operation performed by the UE. In this example, the SRS resource 1 708 has a higher priority over SRS resource 2 710. Therefore, as shown, the UE performs power scaling on SRS resource 2 710, which has lower priority than SRS resource 1 708. The UE applies power scaling factor (X5 mW) on the SRS resource 2 710 until a total transmission power (e.g., transmission power 704 + transmission power 714) in the symbol is below or equal to the maximum transmission power 702.

As described above, note that although FIG. 7 only shows two SRS resources, a greater number of SRS resources may also be used in an SRS resource set or different SRS resource sets.

In some implementations, the UE may determine the priority for the SRS resources in an SRS resource set based on at least one of the followings: SRS resource index within the SRS resource set based on the order of the SRS resources within the SRS resource set, e.g., the configuration order of SRS resources in the SRS resource set or srs-ResourceIdList; the configuration order of SRS resources in a SRS resource list (e.g., srs-ResourceToAddModList) ; the SRS resource identifier (ID) for the SRS resource, e.g., srs-ResourceId; number of ports of the SRS resource; bandwidth of the SRS resource; number of REs per symbol of the SRS resource; number of REs per RB of the SRS resource; whether the SRS resource is for codebook (CB) /non-codebook (NCB) for DCI format 0_1 or DCI format 0_2 or both.

In some examples, the UE may determine the priority of the SRS resource with lower resource index within the SRS resource set or lower ID is higher or lower than that with higher resource index within the SRS resource set or higher ID. In another example, the UE may determine the priority of the SRS resource with more ports is higher or lower than that with fewer ports. In another example, the UE may determine the priority of the SRS resource with wider bandwidth is higher or lower than that with smaller bandwidth. In another example, the UE may determine the priority of an SRS resource with first configuration order is higher or lower than an SRS resource with second configuration order in the SRS resource set or SRS resource list (e.g., srs-ResourceToAddModList) , and so on. In another example, the UE may determine the priority of an SRS resource for CB/NCB for DCI format 0_1 is higher or lower than that for DCI format 0_2. In another example, the UE may determine the priority of an SRS resource for CB/NCB for both DCI format 0_1 and DCI format 0_2 is higher than that for DCI format 0_1 or DCI format 0_2.

In some other implementations, the network entity may configure the priority for the SRS resources. In some other implementations, the UE may report the priority for the SRS resources.

In an embodiment, the network entity may configure the power scaling operation for the SRS resources in an SRS resource set based on one of the options as described in FIGs 4-7. The network entity may provide the configuration by the RRC signaling, MAC CE or DCI. In some examples, the network entity may provide the RRC parameter per SRS resource set, per SRS usage, per BWP, per UL/carrier (e.g., non-supplementary uplink, NUL or supplementary uplink, SUL) , per serving cell or per serving cell group. In another example, the network entity may provide the configuration based on the MAC CE or DCI triggering the SRS resource set.

In some implementations, the UE may determine the power scaling operation according to on one of the operations as described in FIGs 4-7 based on the usage of the SRS resource. In some examples, the UE may determine different power scaling operations for different SRS resource sets with different usages configured. The UE may determine to apply the operation according to FIG. 5 or FIG. 7 for the SRS for non-codebook based transmission. The UE may determine to apply the operation according to FIG. 7 or FIG. 7 for the SRS for the codebook based transmission or antenna switching. The UE may determine apply the power scaling operation according to FIG. 4 for the SRS for the beam management. The UE may report the supported power scaling operation (s) for SRS with different usages separately by the UE capability.

In some other implementations, the UE may determine the power scaling operation as one of the options from FIG. s4-7 based on the power reduction for the SRS.

In some examples, if the UE identifies the transmission power based on one of FIGs. 4-6 cannot meet the criteria for uplink transmission, the UE may determine to apply FIG. 7; otherwise, the UE may determine the power reduction for the SRS resources based on one of FIGs. 4-6

In some implementations, the UE identifies the transmission power cannot meet the criteria for the uplink transmission if it identifies one or multiple of the following scenarios: the transmission power of one of the SRS resources after the power scaling is below the minimum transmission power; the power reduction for one of the SRS resources is above a first threshold; the ratio between the power reduction and the target uplink transmission power based on uplink power control parameter is above a second threshold; or the ratio between the actual transmission power and the target uplink transmission power based on uplink power control parameters is below a third threshold.

The first, second and/or third threshold may be predefined or configured by the network entity.

FIG. 8 is a flow chart illustrating an example procedure 800 for a dynamic power scaling operation selection according to an embodiment.

Referring to FIG. 8, at block 882, the target uplink transmission power for each SRS resource may be determined based on the uplink power control parameters.

At block 884, if the total uplink transmission power in a symbol exceeds the maximum uplink transmission power, the scaled uplink transmission power may be determined based on a power scaling for each overlapped SRS resource according to the power scaling operations described in FIGS. 4-6.

At block 886, if the scaled uplink transmission power is determined meeting the criteria for an uplink transmission, the SRS is transmitted based on the scaled uplink transmission power 888. If the scaled uplink transmission power is determined not meeting the criteria for an uplink transmission, the uplink transmission power scaling for SRS resource (s) is determined based on the priority 890; perform the uplink power scaling for SRS resource (s) with the lowest priority until the total uplink transmission power is below or equal to the maximum uplink transmission power; transmit the SRS resource (s) with lowest priority based on the determined scaled transmission power and remaining SRS resource (s) based on the target uplink transmission power.

In an embodiment, the UE may report the UE capability that it supports the simultaneous transmission for multiple SRS resource sets for a usage, or it supports the simultaneous transmission for multiple SRS resource sets for a usage with the same time-domain behavior. The UE may report the UE capability separately or commonly for different usages. The SRS resource sets may be within one serving cell or bandwidth part. The UE may further report whether it supports the simultaneous transmission for multiple SRS resource sets based on different usages. The UE may report the UE capability for different usage combinations, e.g., codebook and beam management, non-codebook and beam management, codebook and antenna switching and so on, separately or commonly.

Then in some implementations, the network entity may configure the UE to transmit SRS on multiple SRS resource sets with the same usage, e.g., codebook, non-codebook or beam management, based on the same time-domain behavior in overlapped symbol (s) . In some other implementations, the network entity may configure the UE to transmit SRS on multiple SRS resource sets with the different usages based on the same time-domain behavior in overlapped symbol (s) .

In an embodiment, if the UE determines to perform power scaling for the SRS resources in multiple SRS resource sets with the same time domain behavior in a symbol when the total uplink transmission power in the symbol exceeds the maximum transmission power, the UE may perform the power scaling for the SRS resources to maintain the same transmission power for each SRS resource. The UE may determine the transmission power based on the number of overlapped SRS resources in the overlapped symbol, the total maximum uplink transmission power for the SRS resources in the overlapped symbol and the number of overlapped SRS resources in the SRS resource sets or number of overlapped SRS resource sets. The UE may transmit the SRS resources from different SRS resource sets based on the same transmission power in the overlapped symbol.

In some examples, the UE may determine the transmission power in dBm for one SRS resource in the symbol l’ in bandwidth part (BWP) b, carrier f, serving cell c as equation 9 (if P_cmax (i) -P_total (l′) >0) .

Whereindicates the number of overlapped SRS resources in the SRS resource sets for power scaling or the number of overlapped SRS resource sets in the overlapped symbol l’. P_total (l′) is the total linear transmission power of the uplink signals with higher priority than the SRS resource sets for power scaling on the serving cells in one frequency range.

In an embodiment, if the UE determines to perform power scaling for the SRS resources in multiple SRS resource sets with the same time domain behavior in a symbol when the total uplink transmission power in the symbol exceeds the maximum transmission power, the UE may perform equal power scaling for all the overlapped SRS resources in the SRS resource sets in the symbol. When UE perform equal power scaling, UE may use the same power scaling or power reduction factor or value. In some implementations, the UE may transmit the SRS on the SRS resources from different SRS resource sets in the overlapped symbol based on the same transmission power for each RE or for each RE per port.

Thus, the UE may determine the power scaling factor based on the total maximum uplink transmission power for the SRS resources in the overlapped symbol, and the total uplink transmission power for the SRS resources in the overlapped symbol.

In some examples, the UE may determine the transmission power in dBm for one SRS resource in the symbol l’ in bandwidth part (BWP) b, carrier f, serving cell c as equation 10 (if P_cmax (i) -P_total (l′) >0) :

In an embodiment, if the UE determines to perform power scaling for the SRS resources in multiple SRS resource sets with the same time domain behavior in a symbol when the total uplink transmission power in the symbol exceeds the maximum transmission power, the UE may perform equal power scaling for all the overlapped SRS resource sets in the symbol.

Thus, the UE may determine the power scaling factor based on the total maximum uplink transmission power for the SRS resources in the overlapped symbol, the total uplink transmission power for the SRS resources in the overlapped symbol, and the number of overlapped SRS resource set.

Then for each overlapped SRS resource set, the UE may determine to reduce the linear transmission power as follows:

Where S_l′ indicates the number of overlapped SRS resource sets.

Then for each set, if there are multiple overlapped SRS resources in the symbol, the UE may determine the transmission power based on one of the options for SRS resource power scaling within a set or based on one of the operations according to FIGs. 4-8 for intra-set power scaling, where the variables P_total, SRS (l′) -P_cmax (i) +P_total (l′) in equation 3 and 7 can be replaced by Δ_SRS. In some implementations, the UE may transmit the SRS on the SRS resources from one SRS resource set or from different SRS resource sets in the overlapped symbol based on the same transmission power for each RE or for each RE per port.

In an embodiment, if the UE determines to perform power scaling for the SRS resources in multiple SRS resource sets with the same time domain behavior in a symbol when the total uplink transmission power in the symbol exceeds the maximum transmission power, the UE may perform the power scaling for the SRS resource set (s) with lowest priority until the total transmission power in the frequency range is below or equal to the maximum transmission power.

In some implementations, the UE may determine the priority for the SRS resource set with the same time domain behavior based on at least one of the followings: SRS resource set ID; configuration order of SRS resource set in an SRS resource set list (e.g., srs-ResourceSetToAddModList) ; usage for the SRS resource set; number of SRS resources in the SRS resource set; whether the SRS resource set is for CB/NCB for DCI format 0_1 or DCI format 0_2.

In some examples, the UE may determine the priority of the SRS resource set with lower set ID is higher or lower than that with higher set ID. In another example, the UE may determine the priority of the SRS resource set based on the usage as follows: beam management > antenna switching > codebook > non-codebook > positioning. The UE may determine different priority orders in different examples. In another example, the UE may determine the priority of the SRS resource set with more SRS resources is higher or lower than that with fewer SRS resources. In another example, the UE may determine an SRS resource set with first configuration order is higher or lower than an SRS resource set with second configuration order in the SRS resource set list (e.g., srs-ResourceSetToAddModList) , and so on. In another example, the UE determine an SRS resource set for CB/NCB for DCI format 0_1 is higher or lower than that for DCI format 0_2.

In some implementations, if the SRS resource sets are in different serving cells, the UE may determine SRS resource set from primary cell (PCell) or primary secondary cell (PSCell) with higher priority than SRS resource set from secondary cell (SCell) . The UE may further determine the priority for SRS resource sets from SCells based on the serving cell index, e.g., ServCellIndex for the SCell. In some examples, the priority of the SRS resource set from the SCell with lower priority ID is higher or lower than that from the SCell with higher priority.

In some other implementations, the network entity may configure the priority for the SRS resource sets. In some other implementations, the UE may report the priority for the SRS resource sets.

Then for each set, if there are multiple overlapped SRS resources in the symbol, the UE may determine the transmission power based on one of the options for SRS resource power scaling within a set based on one of the power scaling operations according to FIGs. 4-8 for intra-set power scaling.

In an embodiment, the network entity may configure the power scaling operation for the SRS resources in multiple SRS resource sets based on one of the options according to FIGs. 4-7 in the embodiment for power scaling for SRS resources in different SRS resource set. The network entity may provide the configuration by RRC signaling, MAC CE or DCI. In some examples, the network entity may provide the RRC parameter per SRS usage, per BWP, per UL/carrier (e.g., NUL or SUL) , per serving cell or per serving cell group. In another example, the network entity may provide the configuration based on the MAC CE or DCI triggering the SRS resource set.

In some implementations, the UE may determine the power scaling operation based on based on one of the options according to FIGs. 4-7 based on the usage of the SRS resource. In some examples, the UE may determine different power scaling operations for different SRS resource sets with different usages configured. The UE may report the supported power scaling operation (s) for SRS with different usages separately by the UE capability.

In an embodiment, if the power reduction for an SRS resource is above a fourth threshold, or the ratio between the power reduction and the uplink transmission power based on uplink power control parameter is above a fifth threshold, or the ratio between the actual transmission power and the target uplink transmission power based on uplink power control parameters is below a sixth threshold, the UE may report a power scaling indication for the transmission occasion of the SRS resource. The fourth, fifth, and/or sixth threshold may be predefined or configured by the NE.

In some implementations, the UE may report the power scaling indication for an SRS resource based on the SRS on the SRS resource implicitly. In some examples, the UE may transmit the SRS resource based on a first sequence if it identifies a negative power scaling indication, and the UE may transmit the SRS resource based on a second sequence if it identifies a positive power scaling indication. The first and second sequence may correspond to a first sequence ID (e.g., sequenceId) and a second sequence ID (e.g., sequenceId2) respectively, which may be configured by the network entity.

FIG. 9 illustrates an example operation 900 for the SRS transmission based on the power scaling indication according to an embodiment. Operation 982 of FIG. 9 is similar to the block 882 of FIG. 8.

Referring to FIG. 9, at block 902, if the UE identifies the total uplink transmission power in a symbol exceeds the maximum uplink transmission power, the UE may determine the scaled uplink transmission power based on power scaling for each overlapped SRS resources in one or multiple SRS resource sets.

At block 904, if the UE determines that the scaled uplink transmission power meets the criteria for uplink transmission power indication, e.g., power scaling indication report, for an SRS resource, the UE transmits the SRS on the SRS resource based on a first sequence 906. If the UE determines that the scaled uplink transmission power does not meet the criteria for uplink transmission power indication, e.g., power scaling indication report, for an SRS resource, the UE transmits the SRS on the SRS resource based on a second sequence 908.

In some other implementations, the UE may report the power scaling indication for an SRS resource based on an uplink control information (UCI) on PUCCH or PUSCH or a MAC CE. In some examples, the UE may report the power scaling indication on a PUCCH resource configured by the network entity if it identifies a positive power scaling indication, and the UE may not transmit the PUCCH resource if it identifies a negative power scaling indication.

In an embodiment, after receiving a PDCCH scheduling a PUSCH, the UE may transmit the PUSCH associated with the most recent transmitted SRS resource (s) without power scaling before the first symbol of the scheduling PDCCH. The associated SRS resource (s) are indicated by the network entity based on the DCI scheduling the PUSCH. The scheduled PUSCH may not be associated with a SRS with power scaling, even the SRS is the most recent transmitted SRS resource. The UE may transmit the PUSCH based on the same number of ports, the same antenna virtualization operation, and/or the same spatial domain filter as the transmission occasion of the associated SRS resources.

In an embodiment, after receiving the DCI scheduling a PUSCH, the UE may transmit the PUSCH based on the same energy per resource element (EPRE) ratio for each port or layer associated with the associated SRS resource (s) . The associated SRS resource (s) are indicated by the network entity based on the DCI scheduling the PUSCH. The PUSCH is associated with the most recent indicated SRS resource (s) before the first symbol of the scheduling PDCCH.

In some examples, for codebook based PUSCH, a first set of x PUSCH ports may be associated with the first SRS resource from x ports, a second set of y PUSCH ports may be associated with the second SRS resource from y ports and so on.Then if the EPRE ratio of the N indicated SRS resources are {1, m₂, …, m_N} , where m_k indicates the power scaling ratio between the SRS resource k and SRS resource 1, the UE transmits the PUSCH ports associated with the SRS resources based on the same power scaling ratio.

In another example, for non-codebook based PUSCH, a first PUSCH layer may be associated with the first SRS indicated resource, a second PUSCH layer may be associated with the second indicated SRS resource and so on. Then if the EPRE ratio of the N indicated SRS resources are {1, m₂, …, m_N} , the UE transmits the PUSCH layers based on the power ratio of {1, m₂, …, m_N} .

In an embodiment, the network entity may configure whether the UE should transmit the PUSCH associated with the transmission occasion of indicated SRS resource (s) without power scaling/reduction or not. If the network entity configures the UE should transmit the PUSCH associated with the transmission occasion of indicated SRS resource (s) without power reduction, the UE transmits the PUSCH associated with the most recent transmitted SRS on the indicated SRS resource (s) without power scaling or reduction before the first symbol of the scheduling PDCCH; otherwise, the UE should transmit the PUSCH associated with the most recent transmitted SRS on the indicated SRS resource (s) regardless of whether the SRS is with power scaling/reduction or not before the first symbol of the scheduling PDCCH.

FIG. 10 is one example scenario 1000 for the associated SRS determination based on the SRS without power scaling for the PUSCH transmission.

Referring to FIG. 10, the UE transmits SRS resource 1 without power scaling 1002. At a later time, the UE transmits SRS resource 1 with power scaling 1004. The network entity transmits a PDCCH 1006 scheduling a PUSCH 1008 associated with the indicated SRS resource (s) without power scaling 1002 (e.g., SRS resource indicator (SRI) = 0 in the DCI) . In this situation, the UE transmits the PUSCH 1008 associated with the most recent transmitted SRS on the indicated SRS resource (s) without the power scaling 1002 before the first symbol of the scheduling PDCCH 1006. The associated SRS resource (s) are indicated by the network entity based on the DCI scheduling the PUSCH. The scheduled PUSCH 1008 may not be associated with the SRS with power scaling 1004, even though the SRS was the most recently transmitted SRS resource. In some implementations, the UE may transmit the PUSCH based on the same number of ports, the same antenna virtualization operation, and/or the same spatial domain filter as the transmission occasion of the associated SRS resources.

The network entity may provide the configuration by RRC signaling, MAC CE or DCI. In some examples, the network entity may configure an RRC parameter for the configuration per scheduling DCI format, e.g., DCI format 0_1/0_2/0_3, per BWP, per UL/carrier (e.g., NUL or SUL) , per serving cell or per serving cell group. In another example, the network entity may provide the configuration by a DCI field in the DCI, e.g., DCI format 0_1/0_2/0_3, scheduling the PUSCH.

FIGs. 11-12 show methods for implementing one or more aspects of FIGs. 2-10. In particular, FIG. 11 shows an implementation by the UE 102 of the one or more aspects of FIGs. 2-10. FIG. 11 shows an implementation by the network entity 104 of the one or more aspects of FIGs. 2-10.

FIG. 11 illustrates a flowchart 1100 of a method of wireless communication at a UE. With reference to FIGs. 1-10, the method may be performed by the UE 102.

In some embodiments, the UE 102 may optionally transmit 1102, to the network entity 104, a UE capability report indicating support for at least one of: a common power scaling factor for each SRS resource; a common scaled transmission power for each resource element (RE) or resource block (RB) for each SRS resource; an overlapped SRS resources with different bandwidth; an overlapped SRS resources with different number of subcarriers; a partially overlapped SRS resources in time domain; a power scaling or dropping of overlapped SRS resources when the UE determines to perform power scaling for the SRS resources. For example, referring to FIG. 3, the UE 102 transmits 302 a UE capability on the supported operation for an SRS power scaling for the SRS resources in an SRS resource set and/or SRS resources in different SRS resource set.

In some embodiments, the UE 102 receives 1104, from the network entity 104, an SRS resource configuration indicating multiple SRS resources at least partially overlapping in a time-domain. For example, referring to FIG. 3, the UE 102 transmits 304 an RRC signaling configuring at least one of the followings: SRS resources in an SRS resource set with partially or fully overlapped symbol (s) ; SRS resources in different SRS resource set with partially or fully overlapped symbol (s) , and optionally configuring SRS power scaling operation for SRS resources in an SRS resource set and/or SRS resources in different SRS resource sets.

In some embodiments, the UE 102 may optionally receive 1106, from the network entity 104, at least one of: downlink control information, DCI, triggering the SRS resource configuration or a medium access control-control element, MAC-CE, activating the SRS resource configuration. For example, referring to FIG. 3, the UE receives 306 one or multiple MAC CE or DCI activating or triggering the configured SRS resource set (s) and optionally indicating the SRS power scaling operation for the SRS resources in the SRS resource set (s) .

In some embodiments, the UE 102 transmits 1108, to the network entity 104, an SRS from one or more of the multiple SRS resources in a symbol based on a power scaling scheme associated with a respective priority of the multiple SRS resources when a total transmission power exceeds a maximum transmission power in the symbol. For example, referring to FIG. 3, the UE 102 transmits 308 an SRS from the SRS resource set (s) based on a scaled transmission power when the total uplink transmission power exceeds the maximum transmission power.

In some embodiments, the UE 102 may optionally receive 1110, from the network entity 104, a DCI triggering a PUSCH transmission, the DCI indicating one or more multiple SRS resources associated with the PUSCH transmission. For example, referring to FIG. 3, the UE 102 receives 310 a DCI triggering a PUSCH transmission and indicating one or multiple SRS resources in the SRS resource set (s) that the PUSCH is associated with.

In embodiments, the UE 102 may optionally transmit 1112, to the network entity 104, a PUSCH transmission based on the power scaling scheme associated with the indicated SRS resource (s) . In some implementations, the PUSCH transmission is associated with a most recently transmitted SRS resource without power scaling before a first symbol of a scheduling PDCCH. For example, referring to FIG. 3, the UE 102 transmits 312 PUSCH based on the power scaling factors as the indicated SRS resource (s) .

FIG. 11 describes a method from a UE-side of a wireless communication link, whereas FIG. 12 describes a method from a network-side of the wireless communication link.

FIG. 12 is a flowchart 1200 of a method of wireless communication at a network entity. With reference to FIG. 3, the method may be performed by one or more network entities 104, which may correspond to a base station or a unit of the base station, such as the RU 106, the DU 108, and/or the CU 110.

In some embodiments, the network entity 104 may optionally receive 1202, from a UE 102, a UE capability report indicating support for at least one of: a common power scaling factor for each SRS resource; a common scaled transmission power for each resource element (RE) or resource block (RB) for each SRS resource; an overlapped SRS resources with different bandwidth; an overlapped SRS resources with different number of subcarriers; a partially overlapped SRS resources in time domain; a power scaling or dropping of overlapped SRS resources when the UE determines to perform power scaling for the SRS resources. For example, referring to FIG. 3, the network entity 104 receives 302 a UE capability on the supported operation for an SRS power scaling for the SRS resources in an SRS resource set and/or SRS resources in different SRS resource set.

In some embodiments, the network entity 104 transmits 1204, to the UE 102, an SRS resource configuration indicating multiple SRS resources at least partially overlapping in a time-domain. For example, referring to FIG. 3, the UE 102 transmits 304 an RRC signaling configuring at least one of the followings: SRS resources in an SRS resource set with partially or fully overlapped symbol (s) ; SRS resources in different SRS resource set with partially or fully overlapped symbol (s) , and optionally configuring SRS power scaling operation for SRS resources in an SRS resource set and/or SRS resources in different SRS resource sets.

In some embodiments, the network entity 104 may optionally transmit 1206, to the UE 102, at least one of: downlink control information, DCI, triggering the SRS resource configuration or a medium access control-control element, MAC-CE, activating the SRS resource configuration. For example, referring to FIG. 3, the network entity 104 transmits 306 one or multiple MAC CE or DCI activating or triggering the configured SRS resource set (s) and optionally indicating the SRS power scaling operation for the SRS resources in the SRS resource set (s) .

In some embodiments, the network entity 104 receives 1208, from the UE 102, an SRS from one or more of the multiple SRS resources in a symbol based on a power scaling scheme associated with a respective priority of the multiple SRS resources when a total transmission power exceeds a maximum transmission power in the symbol. For example, referring to FIG. 3, the network entity 104 receives 308 from the UE 102, an SRS from the SRS resource set (s) based on a scaled transmission power when the total uplink transmission power exceeds the maximum transmission power.

In some embodiments, the network entity 104 may optionally transmit 1210, to the UE 102, a DCI triggering a PUSCH transmission, the DCI indicating one or more multiple SRS resources associated with the PUSCH transmission. For example, referring to FIG. 3, the network entity 104 transmits 310 a DCI triggering a PUSCH transmission and indicating one or multiple SRS resources in the SRS resource set (s) that the PUSCH is associated with.

In some embodiments, the network entity 104 may optionally receive 1212, from the UE 102, a PUSCH transmission based on the power scaling scheme associated with the indicated SRS resource (s) , In some implementations, the PUSCH transmission is associated with a most recently transmitted SRS resource without power scaling before a first symbol of a scheduling PDCCH. For example, referring to FIG. 3, the network entity 104 receives 312 from the UE 102, a PUSCH based on the power scaling factors as the indicated SRS resource (s) .

A UE apparatus 1302, as described in FIG. 13, may perform the method of flowchart 1100. The one or more network entities 104, as described in FIG. 14, may perform the method of flowchart 1200.

FIG. 13 is a diagram 1300 illustrating an example of a hardware implementation for a UE apparatus 1302. The UE apparatus 1302 may be the UE 102, a component of the UE 102, or may implement UE functionality. The UE apparatus 1302 may include an application processor 1306, which may have on-chip memory 1306’. In examples, the application processor 1306 may be coupled to a secure digital (SD) card 1308 and/or a display 1310. The application processor 1306 may also be coupled to a sensor (s) module 1312, a power supply 1314, an additional module of memory 1316, a camera 1318, and/or other related components.

The UE apparatus 1302 may further include a wireless baseband processor 1326, which may be referred to as a modem. The wireless baseband processor 1326 may have on-chip memory 1326'. Along with, and similar to, the application processor 1306, the wireless baseband processor 1326 may also be coupled to the sensor (s) module 1312, the power supply 1314, the additional module of memory 1316, the camera 1318, and/or other related components. The wireless baseband processor 1326 may be additionally coupled to one or more subscriber identity module (SIM) card (s) 1320 and/or one or more transceivers 1330 (e.g., wireless RF transceivers) .

Within the one or more transceivers 1330, the UE apparatus 1302 may include a Bluetooth module 1332, a WLAN module 1334, an SPS module 1336 (e.g., GNSS module) , and/or a cellular module 1338. The Bluetooth module 1332, the WLAN module 1334, the SPS module 1336, and the cellular module 1338 may each include an on-chip transceiver (TRX) , or in some cases, just a transmitter (TX) or just a receiver (RX) . The Bluetooth module 1332, the WLAN module 1334, the SPS module 1336, and the cellular module 1338 may each include dedicated antennas and/or utilize antennas 1340 for communication with one or more other nodes. For example, the UE apparatus 1302 can communicate through the transceiver (s) 1330 via the antennas 1340 with another UE (e.g., sidelink communication) and/or with a network entity 104 (e.g., uplink/downlink communication) , where the network entity 104 may correspond to a base station or a unit of the base station, such as the RU 106, the DU 108, or the CU 110.

The wireless baseband processor 1326 and the application processor 1306 may each include a computer-readable medium /memory 1326', 1306', respectively. The additional module of memory 1316 may also be considered a computer-readable medium/memory. Each computer-readable medium /memory 1326', 1306', 1316 may be non-transitory. The wireless baseband processor 1326 and the application processor 1306 may each be responsible for general processing, including execution of software stored on the computer-readable medium /memory 1326', 1306', 1316. The software, when executed by the wireless baseband processor 1326 /application processor 1306, causes the wireless baseband processor 1326 /application processor 1306 to perform the various functions described herein. The computer-readable medium /memory may also be used for storing data that is manipulated by the wireless baseband processor 1326 /application processor 1306 when executing the software. The wireless baseband processor 1326 /application processor 1306 may be a component of the UE 102. The UE apparatus 1302 may be a processor chip (e.g., modem and/or application) and include just the wireless baseband processor 1326 and/or the application processor 1306. In other examples, the UE apparatus 1302 may be the entire UE 102 and include the additional modules of the apparatus 1302.

As discussed in FIG. 1 and implemented with respect to FIG. 11, the UE SRS Power Scaling component 140 is configured to receive, from a network entity, an SRS resource configuration indicating multiple SRS resources at least partially overlapping in a time-domain; transmit, to the network entity, an SRS from one or more of the multiple SRS resources in a symbol based on a power scaling scheme associated with a respective priority of the multiple SRS resources when a total transmission power exceeds a maximum transmission power in the symbol.

The UE SRS Power Scaling component 140 may be within the application processor 1306 (e.g., at 140a) , the wireless baseband processor 1326 (e.g., at 140b) , or both the application processor 1306 and the wireless baseband processor 1326. The UE SRS Power Scaling component 140a-140b may be one or more hardware components specifically configured to carry out the stated processes/algorithm, implemented by one or more processors configured to perform the stated processes/algorithm, stored within a computer-readable medium for implementation by the one or more processors, or a combination thereof.

FIG. 14 is a diagram 1400 illustrating an example of a hardware implementation for one or more network entities 104. The one or more network entities 104 may be a base station, a component of a base station, or may implement base station functionality. The one or more network entities 104 may include, or may correspond to, at least one of the RU 106, the DU, 108, or the CU 110. The CU 110 may include a CU processor 1446, which may have on-chip memory 1446'. In some aspects, the CU 110 may further include an additional module of memory 1456 and/or a communications interface 1448, both of which may be coupled to the CU processor 1446. The CU 110 can communicate with the DU 108 through a midhaul link 162, such as an F1 interface between the communications interface 1448 of the CU 110 and a communications interface 1428 of the DU 108.

The DU 108 may include a DU processor 1426, which may have on-chip memory 1426'. In some aspects, the DU 108 may further include an additional module of memory 1436 and/or the communications interface 1428, both of which may be coupled to the DU processor 1426. The DU 108 can communicate with the RU 106 through a fronthaul link 160 between the communications interface 1428 of the DU 108 and a communications interface 1408 of the RU 106.

The RU 106 may include an RU processor 1406, which may have on-chip memory 1406'. In some aspects, the RU 106 may further include an additional module of memory 1416, the communications interface 1408, and one or more transceivers 1430, all of which may be coupled to the RU processor 1406. The RU 106 may further include antennas 1440, which may be coupled to the one or more transceivers 1430, such that the RU 106 can communicate through the one or more transceivers 1430 via the antennas 1440 with the UE 102.

The on-chip memory 1406', 1426', 1446' and the additional modules of memory 1416, 1436, 1456 may each be considered a computer-readable medium /memory. Each computer-readable medium /memory may be non-transitory. Each of the processors 1406, 1426, 1446 is responsible for general processing, including execution of software stored on the computer-readable medium /memory. The software, when executed by the corresponding processor (s) 1406, 1426, 1446 causes the processor (s) 1406, 1426, 1446 to perform the various functions described herein. The computer-readable medium /memory may also be used for storing data that is manipulated by the processor (s) 1406, 1426, 1446 when executing the software. In examples, the network entity SRS Power Scaling component 150may sit at any of the one or more network entities 104, such as at the CU 110; both the CU 110 and the DU 108; each of the CU 110, the DU 108, and the RU 106; the DU 108; both the DU 108 and the RU 106; or the RU 106.

As discussed in FIG. 1 and implemented with respect to FIG. 12, the network entity SRS Power Scaling component 150 is configured to configured to transmit, to a UE, a sounding reference signal, SRS, resource configuration indicating multiple SRS resources at least partially overlapping in a time-domain; receive, from the UE, an SRS from one or more of the multiple SRS resources in a symbol based on a power scaling scheme associated with a respective priority of the multiple SRS resources when a total transmission power exceeds a maximum transmission power in the symbol.

The network entity SRS Power Scaling component 150 may be within one or more processors of the one or more network entities 104, such as the RU processor 1406 (e.g., at 150a) , the DU processor 1426 (e.g., at 150b) , and/or the CU processor 1446 (e.g., at 150c) . The network entity SRS Power Scaling component 150150a-150c may be one or more hardware components specifically configured to carry out the stated processes/algorithm, implemented by one or more processors 1406, 1426, 1446 configured to perform the stated processes/algorithm, stored within a computer-readable medium for implementation by the one or more processors 1406, 1426, 1446, or a combination thereof.

The specific order or hierarchy of blocks in the processes and flowcharts disclosed herein is an illustration of example approaches. Hence, the specific order or hierarchy of blocks in the processes and flowcharts may be rearranged. Some blocks may also be combined or deleted. Dashed lines may indicate optional elements of the diagrams. The accompanying method claims present elements of the various blocks in an example order, and are not limited to the specific order or hierarchy presented in the claims, processes, and flowcharts.

The detailed description set forth herein describes various configurations in connection with the drawings and does not represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough explanation of various concepts. However, these concepts may be practiced without these specific details. In some instances, well known structures and components are shown in block diagram form in order to avoid obscuring such concepts.

Aspects of wireless communication systems, such as telecommunication systems, are presented with reference to various apparatuses and methods. These apparatuses and methods are described in the following detailed description and are illustrated in the accompanying drawings by various blocks, components, circuits, processes, call flows, systems, algorithms, etc. (collectively referred to as “elements” ) . These elements may be implemented using electronic hardware, computer software, or combinations thereof. Whether such elements are implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system.

An element, or any portion of an element, or any combination of elements may be implemented as a “processing system” that includes one or more processors. Examples of processors include microprocessors, microcontrollers, graphics processing units (GPUs) , central processing units (CPUs) , application processors, digital signal processors (DSPs) , reduced instruction set computing (RISC) processors, systems-on-chip (SoC) , baseband processors, field programmable gate arrays (FPGAs) , programmable logic devices (PLDs) , state machines, gated logic, discrete hardware circuits, and other similar hardware configured to perform the various functionality described throughout this disclosure. One or more processors in the processing system may execute software, which may be referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software components, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, or any combination thereof.

If the functionality described herein is implemented in software, the functions may be stored on, or encoded as, one or more instructions or code on a computer-readable medium, such as a non-transitory computer-readable storage medium. Computer-readable media includes computer storage media and can include a random-access memory (RAM) , a read-only memory (ROM) , an electrically erasable programmable ROM (EEPROM) , optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of these types of computer-readable media, or any other medium that can be used to store computer executable code in the form of instructions or data structures that can be accessed by a computer. Storage media may be any available media that can be accessed by a computer.

Aspects, implementations, and/or use cases described herein may be implemented across many differing platform types, devices, systems, shapes, sizes, and packaging arrangements. For example, the aspects, implementations, and/or use cases may come about via integrated chip implementations and other non-module-component based devices, such as end-user devices, vehicles, communication devices, computing devices, industrial equipment, retail/purchasing devices, medical devices, artificial intelligence (AI) -enabled devices, machine learning (ML) -enabled devices, etc. The aspects, implementations, and/or use cases may range from chip-level or modular components to non-modular or non-chip-level implementations, and further to aggregate, distributed, or original equipment manufacturer (OEM) devices or systems incorporating one or more techniques described herein.

Devices incorporating the aspects and features described herein may also include additional components and features for the implementation and practice of the claimed and described aspects and features. For example, transmission and reception of wireless signals necessarily includes a number of components for analog and digital purposes, such as hardware components, antennas, RF-chains, power amplifiers, modulators, buffers, processor (s) , interleavers, adders/summers, etc. Techniques described herein may be practiced in a wide variety of devices, chip-level components, systems, distributed arrangements, aggregated or disaggregated components, end-user devices, etc., of varying configurations.

The description herein is provided to enable a person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not limited to the aspects described herein, but are to be interpreted in view of the full scope of the present disclosure consistent with the language of the claims.

Reference to an element in the singular does not mean “one and only one” unless specifically stated, but rather “one or more. ” Terms such as “if, ” “when, ” and “while” do not imply an immediate temporal relationship or reaction. That is, these phrases, e.g., “when, ” do not imply an immediate action in response to or during the occurrence of an action, but simply imply that if a condition is met then an action will occur, but without requiring a specific or immediate time constraint for the action to occur. The terms “may” , “might” , and “can” , as used in this disclosure, often carry certain connotations. For example, “may” refers to a permissible feature that may or may not occur, “might” refers to a feature that probably occurs, and “can” refers to a capability (e.g., capable of) . The phrase “For example” often carries a similar connotation to “may” and, therefore, “may” is sometimes excluded from sentences that include “for example” or other similar phrases.

Unless specifically stated otherwise, the term “some” refers to one or more. Combinations such as “at least one of A, B, or C” or “one or more of A, B, or C” include any combination of A, B, and/or C, such as A and B, A and C, B and C, or A and B and C, and may include multiples of A, multiples of B, and/or multiples of C, or may include A only, B only, or C only. Sets should be interpreted as a set of elements where the elements number one or more. Terms or articles such as “a” , “an” , and/or “the” may refer to one of an item, feature, element, etc., that the term or article precedes, or may refer to more than one of said item, feature, element, etc. that the term or article precedes. For example, the recitation “a widget” does not preclude reference to multiples of said widget, as “multiple widgets” necessarily includes “a widget” . Hence, the recitation “a widget” may be interpreted as “at least one widget” or, similarly, interpreted as “one or more widgets” .

Unless otherwise specifically indicated, ordinal terms such as “first” and “second” do not necessarily imply an order in time, sequence, numerical value, etc., but are used to distinguish between different instances of a term or phrase that follows each ordinal term.

Reference numbers, as used in the specification and figures, are sometimes cross-referenced among drawings to denote same or similar features. A feature that is exactly the same in multiple drawings may be labeled with the same reference number in the multiple drawings. A feature that is similar among the multiple drawings, but not exactly the same, may be labeled with reference numbers that have different leading numbers but have one or more of the same trailing numbers (e.g., 206, 306, 406, etc., may refer to similar features in the drawings) . Hence, like numbers may refer to like actions.

Structural and functional equivalents to elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are encompassed by the claims. The words “module, ” “mechanism, ” “element, ” “device, ” and the like may not be a substitute for the word “means. ” As such, no claim element is to be construed as a means plus function unless the element is expressly recited using the phrase “means for. ” As used herein, the phrase “based on” shall not be construed as a reference to a closed set of information, one or more conditions, one or more factors, or the like. In other words, the phrase “based on A” , where “A” may be information, a condition, a factor, or the like, shall be construed as “based at least on A” unless specifically recited differently.

The following examples are illustrative only and may be combined with other examples or teachings described herein, without limitation.

Example 1 is a method of wireless communication at a UE, including: receiving , from a network entity, a sounding reference signal, SRS, resource configuration indicating multiple SRS resources at least partially overlapping in a time-domain; and transmitting, to the network entity, an SRS from one or more of the multiple SRS resources in a symbol based on a power scaling scheme associated with a respective priority of the multiple SRS resources when a total transmission power exceeds a maximum transmission power in the symbol.

Example 2 may be combined with Example 1 and further includes the multiple SRS resources have a same priority and the multiple SRS resources have a same time-domain behavior including at least one of: aperiodic, semi-persistent, or periodic.

Example 3 may be combined with any of Examples 1-2 and further includes that the multiple SRS resources are configured in at least one of: a same SRS resource set or different SRS resource sets.

Example 4 may be combined with any of Examples 1-3 and further includes that the power scaling scheme indicates at least one of: to maintain a same transmission power for each SRS resource, to apply an equal power scaling factor to each SRS resource in the symbol, to maintain a same transmission power for each resource element, RE, per port for each SRS resource, to apply an equal power scaling factor for overlapped SRS resources in the symbol, or to apply a power scaling to the one or more of the multiple SRS resources with a lowest priority until the total transmission power is below or equal to the maximum transmission power.

Example 5 may be combined with any of Examples 1-4 and further includes that the respective priority of the multiple SRS resources is based on at least one of: SRS resource index within the SRS resource set; SRS resource identifier (ID) for the SRS resource; number of ports of the SRS resource; bandwidth of the SRS resource; number of REs per symbol of the SRS resource; or number of REs per RB of the SRS resource.

Example 6 may be combined with any of Examples 1-5 and further includes that the power scaling scheme is based on a usage of an SRS resource including at least one of: codebook; non-codebook; beam management; or antenna switching.

Example 7 may be combined with Example 1 and further includes: transmitting, to the network entity, a power scaling report indicating a transmission occasion of the SRS based on at least one of: a power reduction for the one or more of the multiple SRS resources being above a first threshold, a ratio between the power reduction and an uplink transmission power based on an uplink power control parameter being above a second threshold, or a ratio between an actual transmission power and a target uplink transmission power based on the uplink power control parameters being below a third threshold.

Example 8 may be combined with Example 1 and further includes: transmitting, to the network entity, a physical uplink shared channel, PUSCH, transmission based on the power scaling scheme, and further includes that the PUSCH transmission is associated with a most recently transmitted SRS without power scaling before a first symbol of a scheduling physical downlink control channel, PDCCH.

Example 9 may be combined with Example 8 and further includes that the PUSCH transmission is based on a same energy per resource element, EPRE, ratio for each port associated with an SRS resource of the multiple SRS resources.

Example 10 may be combined with Example 8 and further includes that the PUSCH transmission is transmitted based on the power scaling scheme.

Example 11 may be combined with any of Examples 1-10 and further includes that the configuration includes an uplink power control parameter indicating the power scaling scheme.

Example 12 may be combined with any of Examples 1-11 and further includes: transmitting, to the network entity, a UE capability report indicating support for at least one of: a common power scaling factor for each SRS resource; a common scaled transmission power for each resource element (RE) or resource block (RB) for each SRS resource; an overlapped SRS resources with different bandwidth; an overlapped SRS resources with different number of subcarriers; a partially overlapped SRS resources in time domain; a power scaling or dropping of overlapped SRS resources when the UE determines to perform power scaling for the SRS resources.

Example 13 is a method of wireless communication at a network entity, including: transmitting, to a user equipment, UE, a sounding reference signal, SRS, resource configuration indicating multiple SRS resources at least partially overlapping in a time-domain; and receiving, from the UE, an SRS from one or more of the multiple SRS resources in a symbol based on a power scaling scheme associated with a respective priority of the multiple SRS resources when a total transmission power exceeds a maximum transmission power in the symbol.

Example 14 may be combined with Example 13 and further includes that the multiple SRS resources have a same priority and the multiple SRS resources have a same time-domain behavior including at least one of: aperiodic, semi-persistent, or periodic.

Example 15 may be combined with any of Examples 13-14 and further includes that the multiple SRS resources are configured in at least one of: a same SRS resource set or different SRS resource sets.

Example 16 may be combined with any of Examples 13-15 and further includes that the power scaling scheme indicates at least one of: to maintain a same transmission power for each SRS resource, to apply an equal power scaling factor to each SRS resource in the symbol, to maintain a same transmission power for each resource element, RE, per port for each SRS resource, to apply an equal power scaling factor for overlapped SRS resources in the symbol, or to apply a power scaling to the one or more of the multiple SRS resources with a lowest priority until the total transmission power is below or equal to the maximum transmission power.

Example 17 may be combined with any of Examples 13-16 and further includes that the respective priority of the multiple SRS resources is based on at least one of: SRS resource index within the SRS resource set; SRS resource identifier (ID) for the SRS resource; number of ports of the SRS resource; bandwidth of the SRS resource; number of REs per symbol of the SRS resource; or number of REs per RB of the SRS resource.

Example 18 may be combined with any of Examples 13-17 and further includes that the power scaling scheme is based on a usage of an SRS resource including at least one of: codebook; non-codebook; beam management; or antenna switching.

Example 19 may be combined with Example 13 and further includes : receiving, from the UE, a power scaling report indicating a transmission occasion of the SRS based on at least one of: a power reduction for the one or more of the multiple SRS resources being above a first threshold, a ratio between the power reduction and an uplink transmission power based on an uplink power control parameter being above a second threshold, or a ratio between an actual transmission power and a target uplink transmission power based on the uplink power control parameters being below a third threshold.

Example 20 may be combined with Example 13 and further includes: receiving, from the UE, a physical uplink shared channel, PUSCH, transmission based on the power scaling scheme, and further includes that the PUSCH transmission is associated with a most recently transmitted SRS without power scaling before a first symbol of a scheduling physical downlink control channel, PDCCH.

Example 21 may be combined with Example 20 and further includes that the PUSCH transmission is based on a same energy per resource element, EPRE, ratio for each port associated with an SRS resource of the multiple SRS resources.

Example 22 may be combined with Example 20, and further includes that the PUSCH transmission is transmitted based on the power scaling scheme.

Example 23 may be combined with any of Examples 13-22 and further includes that the configuration includes an uplink power control parameter indicating the power scaling scheme.

Example 24 may be combined with any of Examples 13-23 and further includes: transmitting, to the network entity, a UE capability report indicating support for at least one of: a common power scaling factor for each SRS resource; a common scaled transmission power for each resource element (RE) or resource block (RB) for each SRS resource; an overlapped SRS resources with different bandwidth; an overlapped SRS resources with different number of subcarriers; a partially overlapped SRS resources in time domain; a power scaling or dropping of overlapped SRS resources when the UE determines to perform power scaling for the SRS resources.

Example 25 is an apparatus for wireless communication for implementing a method as in any of examples 1-24.

Example 26 is an apparatus for wireless communication including means for implementing a method as in any of examples 1-24.

Example 27 is a non-transitory computer-readable medium storing computer executable code, the code when executed by a processor causes the processor to implement a method as in any of examples 1-24.

Claims

A method of wireless communication at a user equipment, UE, (102) comprising:

receiving (304) , from a network entity (104) , a sounding reference signal, SRS, resource configuration indicating multiple SRS resources at least partially overlapping in a time-domain; and

transmitting (308) , to the network entity (104) , an SRS from one or more of the multiple SRS resources in a symbol based on a power scaling scheme associated with a respective priority of the multiple SRS resources when a total transmission power exceeds a maximum transmission power in the symbol.
The method of claim 1, wherein the multiple SRS resources have a same priority and the multiple SRS resources have a same time-domain behavior including at least one of: aperiodic, semi-persistent, or periodic.
The method of any of claims 1-2, wherein the multiple SRS resources are configured in at least one of: a same SRS resource set or different SRS resource sets.
The method of any of claims 1-3, wherein the power scaling scheme indicates at least one of:

to maintain a same transmission power for each SRS resource,

to apply an equal power scaling factor to each SRS resource in the symbol,

to maintain a same transmission power for each resource element, RE, per port for each SRS resource,

to apply an equal power scaling factor for overlapped SRS resources in the symbol, or

to apply a power scaling to the one or more of the multiple SRS resources with a lowest priority until the total transmission power is below or equal to the maximum transmission power.
The method of any of claims 1-4, wherein the respective priority of the multiple SRS resources is based on at least one of:

SRS resource index within the SRS resource set;

SRS resource identifier, ID, for the SRS resource;

number of ports of the SRS resource;

bandwidth of the SRS resource;

number of REs per symbol of the SRS resource; or

number of REs per RB of the SRS resource.
The method of any of claims 1-5, wherein the power scaling scheme is based on a usage of an SRS resource including at least one of:

codebook;

non-codebook;

beam management; or

antenna switching.
The method of claim 1, further comprising:

transmitting (308) , to the network entity (104) , a power scaling report indicating a transmission occasion of the SRS based on at least one of:

a power reduction for the one or more of the multiple SRS resources being above a first threshold,

a ratio between the power reduction and an uplink transmission power based on an uplink power control parameter being above a second threshold, or

a ratio between an actual transmission power and a target uplink transmission power based on the uplink power control parameters being below a third threshold.
The method of claim 1, further comprising:

transmitting (312) , to the network entity (104) , a physical uplink shared channel, PUSCH, transmission based on the power scaling scheme, wherein the PUSCH transmission is associated with a most recently transmitted SRS without power scaling before a first symbol of a scheduling physical downlink control channel, PDCCH.
The method of claim 8, wherein the PUSCH transmission is based on a same energy per resource element, EPRE, ratio for each port associated with an SRS resource of the multiple SRS resources.
The method of claim 8, wherein the PUSCH transmission is transmitted based on the power scaling scheme.
The method of any of claims 1-10, wherein the configuration includes an uplink power control parameter indicating the power scaling scheme.
The method of any of claims 1-11, further comprising:

transmitting (302) , to the network entity (104) , a UE capability report indicating support for at least one of:

a common power scaling factor for each SRS resource;

a common scaled transmission power for each resource element, RE, or resource block, RB, for each SRS resource;

an overlapped SRS resources with different bandwidth;

an overlapped SRS resources with different number of subcarriers;

a partially overlapped SRS resources in time domain;

a power scaling or dropping of overlapped SRS resources when the UE determines to perform power scaling for the SRS resources.
A method of wireless communication at a network entity, comprising:

transmitting (304) , to a user equipment, UE, (102) , a sounding reference signal, SRS, resource configuration indicating multiple SRS resources at least partially overlapping in a time-domain; and

receiving (308) , from the UE (102) , an SRS from one or more of the multiple SRS resources in a symbol based on a power scaling scheme associated with a respective priority of the multiple SRS resources when a total transmission power exceeds a maximum transmission power in the symbol.
The method of claim 13, wherein the multiple SRS resources have a same priority and the multiple SRS resources have a same time-domain behavior including at least one of: aperiodic, semi-persistent, or periodic.
The method of any of claims 1-14, wherein the power scaling scheme indicates at least one of:

to maintain a same transmission power for each SRS resource,

to apply an equal power scaling factor to each SRS resource in the symbol,

to maintain a same transmission power for each resource element, RE, per port for each SRS resource,

to apply an equal power scaling factor for overlapped SRS resources in the symbol, or

to apply a power scaling to the one or more of the multiple SRS resources with a lowest priority until the total transmission power is below or equal to the maximum transmission power.
An apparatus for wireless communication comprising a memory, a transceiver, and a processor coupled to the memory and the transceiver, the apparatus being configured to implement a method as in any of claims 1-15.