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CN-121986449-A - SRS antenna switching for 3TX UE

CN121986449ACN 121986449 ACN121986449 ACN 121986449ACN-121986449-A

Abstract

A system and method for Sounding Reference Signal (SRS) antenna switching for three Transmit (TX) User Equipments (UEs) is provided. In some embodiments, a method performed by a UE includes transmitting UE capability signaling indicating that three transmit antennas are supported and receiving a Radio Resource Control (RRC) configuration indicating that the UE should apply a first antenna switch or a second antenna switch. In this way, the number of Orthogonal Frequency Division Multiplexing (OFDM) symbols required to probe a number of UE RX antennas is reduced compared to using a conventional SRS antenna switching configuration.

Inventors

  • Andreas Nelson
  • Polite Jacob pine

Assignees

  • 瑞典爱立信有限公司

Dates

Publication Date
20260505
Application Date
20241010
Priority Date
20231010

Claims (20)

  1. 1. A method performed by a user equipment, UE, the method comprising: Transmitting (900) UE capability signaling indicating support of three transmit antennas, and A radio resource control, RRC, configuration is received (902) to indicate that the UE should apply either a first antenna switch or a second antenna switch.
  2. 2. The method of claim 1, wherein the first antenna switch and the second antenna switch comprise one of the group consisting of a 3T6R or 4T8R antenna switch, a 3T3R or 3T6R antenna switch, a 3T8R antenna switch, and any combination of these.
  3. 3. The method of claim 1, wherein the UE capability signaling comprises a new bit field comprising one or more of { t3r3, t3r4r, t3r6, t3r8}.
  4. 4. A method according to any one of claims 1 to 3, wherein: The UE capability signaling indicates whether the UE supports one or more corresponding sounding reference signal, SRS, antenna switching configurations.
  5. 5. The method of any one of claims 1 to 4, wherein: If the UE capability signaling indication txry, the UE can be configured with xTyR antenna switching.
  6. 6. The method of any one of claims 1 to 5, wherein: If the UE has 3 Tx and 4 Rx, the UE indicates that legacy t2r4 antenna switching is supported, which legacy t2r4 antenna switching can be used to probe 4 UE Rx antennas in two orthogonal frequency division multiplexing OFDM symbols + one symbol gap period.
  7. 7. The method of any one of claims 1 to 6, wherein: if the UE has 3 Tx and 4 Rx, the UE indicates that a new t3r3 antenna switching is supported.
  8. 8. The method of any one of claims 1 to 7, wherein: When a UE is configured with a 3T8R antenna switch, the UE detects 3 SRS ports twice and 2 SRS ports a third time.
  9. 9. The method of any one of claims 1 to 8, wherein the one or more SRS resources comprise three ports.
  10. 10. The method of claim 9, wherein the three ports comprise one of: 4-port SRS resources, wherein the UE empties one of the SRS ports; Two or three cascaded SRS resources, wherein the total number of SRS ports on the cascaded SRS resources is equal to three, and New three-port SRS resources are introduced and used.
  11. 11. The method of any one of claims 1 to 10, wherein: the power scaling for all SRS ports should be the same so that the UE should apply the same power for each SRS port regardless of whether there are two or three SRS ports transmitted for each SRS resource.
  12. 12. The method of any one of claims 1 to 11, wherein: for an SRS transmission opportunity to transmit an SRS resource containing m SRS ports, the SRS resource belongs to an SRS resource set which also includes at least one SRS resource with three ports and is used for antenna switching "ANTENNASWITCHING", and the SRS power is m/3 of the SRS power of the SRS transmission opportunity to transmit the SRS resource containing three SRS ports.
  13. 13. The method of any one of claims 1 to 12, wherein: If the UE is configured with one or more SRS resource sets that are used for antenna switching and SRS resources with different numbers of ports are configured in the SRS resource sets, the UE knows that the SRS resources should be concatenated to build a three-port SRS resource.
  14. 14. The method of any one of claims 1 to 13, further comprising: An additional configuration is received indicating that the UE should blank one SRS port for a 4-port SRS resource.
  15. 15. The method of claim 14, wherein the configuring is configured in an SRS resource information element IE specified in TS 38.331.
  16. 16. The method of claim 14, wherein the configuration is configured in an SRS resource set information element IE specified in TS 38.331.
  17. 17. A method performed by a network node, the method comprising: receiving (1000) user equipment UE capability signaling indicating support of three transmit antennas, and A radio resource control, RRC, configuration is sent (1002) to indicate that the UE should apply either a first antenna switch or a second antenna switch.
  18. 18. The method of claim 17, wherein the first antenna switch and the second antenna switch comprise one of the group consisting of a 3T6R or 4T8R antenna switch, a 3T3R or 3T6R antenna switch, a 3T8R antenna switch, and any combination thereof.
  19. 19. The method according to claim 17, wherein: the UE capability signaling includes a new bit field including one or more of { t3r3, t3r4r, t3r6, t3r8}.
  20. 20. The method of any one of claims 17 to 19, wherein: The UE capability signaling indicates whether the UE supports one or more corresponding sounding reference signal, SRS, antenna switching configurations.

Description

SRS antenna switching for 3TX UE RELATED APPLICATIONS The present application claims the benefit of provisional patent application Ser. No. 63/589,142, filed 10/2023, 10, the disclosure of which is incorporated herein by reference in its entirety. Technical Field The present disclosure relates generally to antenna switching. Background Parameter set In the time domain, the NR DL transmission and the NR UL transmission are organized into subframes of equal size, each subframe being 1ms. The subframe is further divided into a plurality of slots of equal duration. The slot length depends on the parameter set (i.e., depends on SCS and CP). For a 15kHz SCS, there is only one slot per subframe. Generally, forThe kHz SCS (wherein,Is SCS configuration) with each subframe presentAnd each time slot. Each slot consists of 14 symbols (for extended CP, each slot consists of 12 symbols unless configured with extended CP). In the frequency domain, the channel bandwidth is divided into RBs, each RB corresponding to 12 consecutive subcarriers. One subcarrier during one symbol interval forms one RE, which is the smallest physical resource in NR. Carrier aggregation NR supports CA of up to 16 CCs. A CA-enabled UE may transmit/receive on multiple CCs simultaneously, where different CCs may have different channel bandwidths and/or duplexing schemes (i.e., TDD or FDD). In FR1 (i.e., for operating bands n1 to n 105), a channel bandwidth of up to 100MHz is supported. In FR2 (i.e., for operating bands n257 to n 263), a channel bandwidth of up to 400MHz is supported. The 3GPP TS 38.101-1 and 3GPP TS 38.101-2 list operating bands supporting (continuous and discontinuous) intra-band CA and inter-band CA for FR1 and FR2, respectively. For in-band CA, the CCs are in the same operating frequency band. For inter-band CA, CCs are in different operating frequency bands. In the NR specification, CCs are referred to as cells. One of the cells is called a PCell and is the cell to which the UE is initially connected. After connecting the UE, one or more scells may be additionally configured. Furthermore, the SCell may be dynamically activated/deactivated (via MAC CE signaling). When CA is not configured, the UE will transmit/receive only on the PCell. In DL and UL, the number of cells need not be the same. Typically, there are more DL cells than UL cells, since there are generally more DL traffic than UL traffic. RBs within a cell (across a channel bandwidth) are called CRBs and numbered starting from 0. The first subcarrier in CRB0 is called reference point a, which is signaled to the UE as part of SIB 1. Bandwidth part NR is designed to support very large channel bandwidths (up to 400 MHz), but not all UEs can handle such large channel bandwidths. Thus, the UE may operate within a cell in a contiguous subset of CRBs. This subset is called BWP. For each serving cell, the UE may be configured with up to four DL BWP and four UL BWP, wherein different parameter sets may be configured for different BWP. The starting location and bandwidth of BWP are RRC configured. For each serving cell, only one DL BWP and one UL BWP are active at the same time. For TDD, active DL BWP and UL BWP must share the same center frequency. For FDD, this is not required. In DL, the UE does not expect to receive PDCCH and/or PDSCH outside of active BWP, for example. In UL, the UE does not expect to transmit PUCCH and/or PUCCH outside of active BWP. NW may switch active BWP via DCI signaling. For example, DCI format 1_1 (for scheduling DL transmissions) and DCI format 0_1 (for scheduling UL transmissions) include up to 2 bits of a "BWP indicator" field for switching BWP for DL and UL transmissions, respectively. RBs within BWP are called PRBs and are numbered starting from 0. When the NW schedules DL or UL transmissions, a set of VRBs mapped to PRBs are signaled. In DL, interleaving and non-interleaving mapping are supported. In the UL, only non-interlace mapping is supported, where there is a one-to-one mapping between VRBs and CRBs. Hereinafter, unless otherwise stated, it is assumed that there is a one-to-one mapping between VRBs and PRBs, and that both VRBs and CRBs are simply referred to using RBs. SRS The SRS is a UL RS based on Zadoff-Chu sequences for providing CSI to the NW. Uses of SRS include, for example, deriving appropriate transmit/receive beams and/or performing link adaptation (i.e., setting transmission rank and MCS) and for determining PDSCH and PUSCH precoding matrices. SRS configuration SRS is configured via RRC signaling, where portions of the configuration can be updated (to reduce latency) via MAC CE signaling. In configuring SRS transmission, the gNB configures an SRS resource list and an SRS resource set list through an SRS-Config IE (see ASN fragment from 3gpp TS 38.331 version 17.2.0 below): SRS-Config ::= SEQUENCE { srs-ResourceSetToReleaseList SEQUENCE (SIZE(1..maxNrofSRS-ResourceSets)) OF SRS-ResourceSetId OPTIONAL, -- Need N srs-ResourceSetT