WO2025147173A1 - Method for srs transmission and reception and device thereof - Google Patents

Abstract

A method according to one embodiment of the present specification comprises the steps of: receiving configuration information from a base station; and transmitting SRSs to the base station on the basis of at least one SRS resource set. The at least one SRS resource set, which is related to antenna switching, is configured on the basis of the configuration information. The SRSs are transmitted in different symbols on the basis of a plurality of SRS resources in the at least one SRS resource set. On the basis that the respective numbers of ports configured for the plurality of SRS resources are different, the transmission power associated with each port of one of the plurality of SRS resources is the same.

Description

SRS transmission and reception method and device thereof

This specification relates to an SRS transmission and reception method and a device therefor.

Mobile communication systems were developed to provide voice services while ensuring user activity. However, mobile communication systems have expanded their scope to include data services as well as voice, and currently, due to the explosive increase in traffic, resource shortages are occurring and users are demanding higher-speed services, so more advanced mobile communication systems are required.

The requirements for the next generation mobile communication system are that it should be able to accommodate explosive data traffic, dramatically increase the data rate per user, accommodate a greatly increased number of connected devices, support very low end-to-end latency, and support high energy efficiency. To this end, various technologies are being studied, including dual connectivity, massive multiple input multiple output (MIMO), in-band full duplex, non-orthogonal multiple access (NOMA), super wideband support, and device networking.

According to the existing standard, the SRS transmission power of an SRS resource is evenly distributed across the ‘ports of the SRS resource’ in a ‘symbol’. In the case of antenna switching for DL CSI acquisition, multiple SRS resources can be transmitted in different symbols.

Regarding the above-described antenna switching, the number of ports set for each of the plurality of SRS resources may be different depending on the UE capability to be supported in the future (e.g., 4T6R, 2T3R, 3T8R, etc.) (e.g., 4 port SRS + 2 port for 4T6R). In this case, a problem occurs in which the transmission power of each port varies for each symbol.

The purpose of this specification is to propose a method to solve the above-mentioned problems.

The technical problems to be achieved in this specification are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art to which the present invention belongs from the description below.

A method according to one embodiment of the present disclosure comprises the steps of receiving configuration information from a base station and transmitting an SRS to the base station based on at least one SRS resource set. The at least one SRS resource set related to antenna switching is configured based on the configuration information.

The above SRS is transmitted in different symbols based on a plurality of SRS resources within the at least one SRS resource set.

Based on the number of ports set for each of the plurality of SRS resources being different, the transmission power associated with each port of one of the plurality of SRS resources is characterized in that it is the same.

The above multiple SRS resources may be associated with the same SRS transmission occasion. The transmission power for the SRS may be determined based on the same SRS transmission occasion.

The transmit power for the above SRS can be equally split across ports based on the plurality of SRS resources in the different symbols.

Among the port-specific transmission powers determined for the plurality of SRS resources, the lowest transmission power can be applied to the ports of the plurality of SRS resources.

The number of ports set for each of the above multiple SRS resources may be the same.

The linear value of the transmission power for the above SRS can be evenly distributed across the ports of each SRS resource of each SRS resource set in the symbol.

The above at least one SRS resource set can be configured based on UE capability. The UE capability, xTyR, can indicate that the UE is capable of transmitting SRS on x ports based on y antennas.

The above y antennas may be based on all or a subset of the UE receive antennas.

Based on the UE capability being 3TyR: each SRS resource in the at least one SRS resource set may include four antenna ports. In each SRS resource, the SRS may be transmitted based on at least one antenna port among the four antenna ports.

Based on the UE capability being 3T3R or 3T6R: the at least one antenna port can be three antenna ports.

The above three antenna ports may be three antenna ports based on the ascending order of antenna port indices among the above four antenna ports.

A terminal according to another embodiment of the present disclosure comprises one or more transceivers, one or more processors, and one or more memories coupled to the one or more processors and storing instructions.

The above instructions are characterized in that they cause the terminal to perform all steps of any one of the above methods based on being executed by the one or more processors.

A device according to another embodiment of the present disclosure comprises one or more memories and one or more processors operatively connected to the one or more memories. The one or more memories are characterized in that they store instructions that cause the device to perform all steps of any one of the methods based on being executed by the one or more processors.

In another embodiment of the present disclosure, one or more non-transitory computer-readable storage media store instructions, which are executable by one or more processors and are characterized by causing a terminal to perform all steps of one of the methods.

A method according to another embodiment of the present disclosure comprises the steps of transmitting configuration information to a terminal and receiving an SRS from the terminal based on at least one SRS resource set. The at least one SRS resource set related to antenna switching is configured based on the configuration information.

The above SRS is received in different symbols based on a plurality of SRS resources within the at least one SRS resource set.

Based on the number of ports set for each of the plurality of SRS resources being different, the transmission power associated with each port of one of the plurality of SRS resources is characterized in that it is the same.

A base station according to another embodiment of the present disclosure includes one or more transceivers, one or more processors, and one or more memories coupled to the one or more processors and storing instructions.

The above instructions are characterized in that they cause the base station to perform all steps of the method based on being executed by the one or more processors.

According to an embodiment of the present specification, it is possible to prevent the transmission power of each port from changing for each symbol when transmitting SRS for antenna switching. Specifically, when SRS is transmitted based on SRS resources having different numbers of ports for each symbol, it is possible to prevent the accuracy of DL CSI related to Rx antennas of a terminal from deteriorating.

The effects that can be obtained from this specification are not limited to the effects mentioned above, and other effects that are not mentioned can be clearly understood by a person having ordinary skill in the art to which this specification belongs from the description below.

Figure 1 is a flowchart showing an example of a UL BM procedure using SRS.

Figure 2 is a diagram illustrating flexible aperiodic SRS transmission timing control.

Figure 3 is a diagram illustrating partial band SRS transmission.

FIG. 4 is a flowchart illustrating a method according to one embodiment of the present specification.

FIG. 5 is a flowchart illustrating a method according to another embodiment of the present specification.

FIG. 6 is a drawing showing the configuration of a first device and a second device according to an embodiment of the present specification.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The detailed description set forth below together with the accompanying drawings is intended to explain exemplary embodiments of the present invention and is not intended to represent the only embodiments in which the present invention may be practiced. The following detailed description includes specific details in order to provide a thorough understanding of the present invention.

In some cases, to avoid obscuring the concept of the present invention, well-known structures and devices may be omitted or illustrated in block diagram format focusing on the core functions of each structure and device.

Hereinafter, downlink (DL) means communication from a base station to a terminal, and uplink (UL) means communication from a terminal to a base station. In the downlink, a transmitter may be part of a base station, and a receiver may be part of a terminal. In the uplink, a transmitter may be part of a terminal, and a receiver may be part of a base station. The base station may be expressed as a first communication device, and the terminal may be expressed as a second communication device. A base station (BS) may be replaced by terms such as a fixed station, Node B, eNB (evolved-NodeB), gNB (Next Generation NodeB), BTS (base transceiver system), access point (AP: Access Point), network (5G network), AI system, RSU (road side unit), vehicle, robot, drone (Unmanned Aerial Vehicle, UAV), AR (Augmented Reality) device, VR (Virtual Reality) device, etc. In addition, the terminal may be fixed or mobile, and may be replaced with terms such as UE (User Equipment), MS (Mobile Station), UT (user terminal), MSS (Mobile Subscriber Station), SS (Subscriber Station), AMS (Advanced Mobile Station), WT (Wireless terminal), MTC (Machine-Type Communication) device, M2M (Machine-to-Machine) device, D2D (Device-to-Device) device, vehicle, robot, AI module, drone (Unmanned Aerial Vehicle, UAV), AR (Augmented Reality) device, VR (Virtual Reality) device, etc.

< SRS related actions >

A UE may be configured with one or more Sounding Reference Symbol (SRS) resource sets (via higher layer signaling, RRC signaling, etc.) configured by (higher layer parameter) SRS-ResourceSet. For each SRS resource set, the UE may be configured with K≥1 SRS resources (higher layer parameter SRS-resource). Here, K is a natural number, and the maximum value of K is indicated by SRS_capability.

Figure 1 is a flowchart showing an example of a UL BM procedure using SRS.

- The terminal receives RRC signaling (e.g. SRS-Config IE) including a usage parameter from the base station (S110). For example, the usage parameter may be set to ‘beam management’, ‘codebook’, ‘nonCodebook’, or ‘antennaSwitching’.

Table 1 shows an example of SRS-Config IE(Information Element), which is used for SRS transmission configuration. SRS-Config IE includes a list of SRS-Resources and a list of SRS-ResourceSets. Each SRS resource set means a set of SRS-resources.

The network can trigger the transmission of an SRS resource set using the configured aperiodicSRS-ResourceTrigger (L1 DCI).

In Table 1, usage represents a higher layer parameter indicating whether the SRS resource set is used for beam management and for codebook-based or non-codebook-based transmission. 'spatialRelationInfo' is a parameter indicating the setting of spatial relation between the reference RS and the target SRS. Here, the reference RS can be an SSB, CSI-RS, or SRS corresponding to the L1 parameter 'SRS-SpatialRelationInfo'. The usage is set for each SRS resource set.

- The terminal determines the Tx beam for the SRS resource to be transmitted based on the SRS-SpatialRelation Info included in the SRS-Config IE (S120). Here, the SRS-SpatialRelation Info is set for each SRS resource, and indicates whether to apply the same beam as the beam used in SSB, CSI-RS, or SRS for each SRS resource. In addition, the SRS-SpatialRelationInfo may or may not be set for each SRS resource.

- If SRS-SpatialRelationInfo is set in the SRS resource, the same beam used in SSB, CSI-RS or SRS is applied and transmitted. However, if SRS-SpatialRelationInfo is not set in the SRS resource, the terminal randomly determines a Tx beam and transmits SRS through the determined Tx beam (S130).

- Additionally, the terminal may or may not receive feedback on SRS from the base station (S140).

At least one of the terminal/base station operations based on S110 to S140 described above may be combined and applied with at least one of the embodiments described below (e.g., at least one of Proposals 1 to 5).

< Sounding reference singal (SRS) >

In Rel-15 NR, spatialRelationInfo can be utilized to indicate a transmission beam to be used when a base station transmits a UL channel to a terminal. The base station can indicate which UL transmission beam to use when transmitting PUCCH and SRS by setting a DL reference signal (e.g., SSB-RI, CRI (P/SP/AP)) or SRS (i.e., SRS resource) as a reference RS for the target UL channel and/or target RS through RRC configuration. In addition, when the base station schedules a PUSCH to a terminal, the transmission beam indicated by the base station and used for SRS transmission is indicated as a transmission beam for PUSCH through the SRI field and is used as the PUSCH transmission beam of the terminal.

< SRS for 'codebook' and 'non-codebook' >

First, in case of CB UL, the base station first sets and/or instructs the terminal to transmit an SRS resource set for the purpose of ‘CB’, and the terminal can transmit any n port SRS resource within the corresponding SRS resource set. The base station acquires a UL channel based on the corresponding SRS transmission, and can utilize this for PUSCH scheduling of the terminal. Thereafter, the base station performs PUSCH scheduling through UL DCI, and can instruct the PUSCH (transmission) beam of the terminal by instructing the SRS resource for the purpose of ‘CB’ previously transmitted by the terminal through the SRI field of the DCI. In addition, the base station can instruct the UL rank and UL precoder by instructing the uplink codebook through the TPMI field. Through this, the terminal can perform PUSCH transmission as instructed.

Next, in the case of NCB UL, the base station first sets and/or instructs the terminal to transmit an SRS resource set for a ‘non-CB’ purpose, and the terminal determines a precoder of SRS resources (maximum 4 resources, 1 port per resource) within the SRS resource set based on reception of an NZP CSI-RS connected to the SRS resource set and transmits the SRS resources simultaneously. Thereafter, the base station performs PUSCH scheduling through UL DCI, and instructs some of the SRS resources for ‘non-CB’ purposes previously transmitted by the terminal through the SRI field of the DCI, thereby instructing the PUSCH (transmission) beam of the terminal, and at the same time instructing the UL rank and UL precoder. Through this, the terminal can perform PUSCH transmission as instructed.

< SRS for 'beam management' >

SRS can be utilized for beam management. Specifically, UL BM can be performed through beamformed UL SRS transmission, and whether or not to apply UL BM of SRS resource set is configured by (higher layer parameter) usage. If usage is set to 'BeamManagement(BM)', only one SRS resource can be transmitted for each of multiple SRS resource sets at a given time instant. The UE can be configured with one or more Sounding Reference Symbol (SRS) resource sets configured by (higher layer parameter) SRS-ResourceSet (via higher layer signaling, RRC signaling, etc.). For each SRS resource set, the UE can be configured with K≥1 SRS resources (higher layer parameter SRS-resource). Here, K is a natural number, and the maximum value of K is indicated by SRS_capability.

< SRS for 'antennaSwitching' >

SRS can be used to acquire DL CSI (Channel State Information) information (i.e. DL CSI acquisition). As a specific example, in a single cell or multi cell (e.g. CA) situation based on TDD, a BS (Base Station) can schedule transmission of SRS to a UE (User Equipment), and then measure the SRS from the UE. In this case, the BS can perform scheduling of DL signals/channels to the UE based on the measurement by SRS, assuming DL/UL reciprocity. In this case, with respect to DL CSI acquisition based on SRS, the SRS can be set for antenna switching purposes.

For example, according to the standard (e.g. 3gpp TS38.214), the purpose of SRS can be set to the base station and/or terminal using a higher layer parameter (e.g. usage of RRC parameter SRS-ResourceSet). In this case, the purpose of SRS can be set to beam management purpose, codebook transmission purpose, non-codebook transmission purpose, antenna switching purpose, etc.

Below, we will examine specifically the case where SRS transmission (i.e., transmission of SRS resources or a set of SRS resources) is set for antenna switching purposes among the above purposes.

For example, for a terminal with partial reciprocity, SRS transmission based on antenna switching (i.e., transmit antenna switching) may be supported for acquisition of DL (downlink) CSI (Channel State Information) through SRS transmission in situations such as TDD (Time Division Duplex). When antenna switching is applied, approximately 15 μs may be generally required between SRS resources (and/or between SRS resources and PUSCH/PUCCH resources) for antenna switching of the terminal. Considering this, a (minimum) guard period as shown in Table 2 below may be defined.

는 서브캐리어 간격(subcarrier spacing)을 나타내며, Y는 보호 구간의 심볼 수 즉, 보호 구간의 길이(length)를 나타낸다. 표 2를 참고하면, 상기 보호 구간은 뉴머롤로지를 결정하는 파라미터 μ에 기반하여 설정될 수 있다. 상기 보호 구간에서, 단말은 다른 어떤 신호도 전송하지 않도록 설정되며, 상기 보호 구간은 온전히 안테나 스위칭에 이용되도록 설정될 수 있다. 일례로, 상기 보호 구간은 동일한 슬롯(same slot)에서 전송되는 SRS 자원들을 고려하여 설정될 수 있다. 특히, 단말이 인트라-슬롯 안테나 스위칭(intra-slot antenna switching)으로 설정된 비주기적(aperiodic) SRS를 전송하도록 설정 및/또는 지시된 경우, 해당 단말은 지정된 SRS 자원마다 서로 다른 전송 안테나를 사용하여 SRS를 전송하게 되며, 각 자원 사이에 상술한 보호 구간이 설정될 수 있다.In Table 2, μ represents numerology,

represents a subcarrier spacing, and Y represents the number of symbols of the guard interval, i.e., the length of the guard interval. Referring to Table 2, the guard interval can be set based on a parameter μ that determines a numerology. In the guard interval, the terminal is set not to transmit any other signal, and the guard interval can be set to be entirely used for antenna switching. For example, the guard interval can be set considering SRS resources transmitted in the same slot. In particular, when the terminal is set and/or instructed to transmit an aperiodic SRS set with intra-slot antenna switching, the terminal transmits the SRS using different transmission antennas for each designated SRS resource, and the above-described guard interval can be set between each resource.

In addition, as described above, if the terminal is configured with SRS resources and/or SRS resource sets for antenna switching purposes through upper layer signaling, the terminal may be configured to perform SRS transmission based on terminal capability (UE capability) related to antenna switching. Here, the capability of the terminal related to antenna switching may be '1T2R', '2T4R', '1T4R', '1T4R/2T4R', '1T1R', '2T2R', '4T4R', etc. Here, 'mTnR' may mean terminal capability supporting m transmissions and n receptions.

(Example S1) For example, for a terminal supporting 1T2R, up to two SRS resource sets can be set with different values for resourceType of the upper layer parameter SRS-ResourceSet. Here, each SRS resource set can have two SRS resources transmitted in different symbols, and each SRS resource in the given SRS resource set can configure a single SRS port. In addition, the SRS port for the second SRS resource in the SRS resource set can be set to be associated with a different UE antenna port than the SRS port for the first SRS resource in the same SRS resource set.

(Example S2) For another example, for a terminal supporting 2T4R, up to two SRS resource sets can be set with different values for resourceType of the upper layer parameter SRS-ResourceSet. Here, each SRS resource set can have two SRS resources transmitted in different symbols, and each SRS resource in the given SRS resource set can configure two SRS ports. In addition, the SRS port pair for the second SRS resource in the SRS resource set can be set to be associated with a different UE antenna port than the SRS port pair for the first SRS resource in the same SRS resource set.

(Example S3) As another example, for a terminal supporting 1T4R, SRS resource sets may be configured in different ways depending on whether SRS transmission is configured to be periodic, semi-persistent, and/or aperiodic. First, if SRS transmission is configured to be periodic or semi-persistent, 0 SRS resource set or 1 SRS resource set consisting of 4 SRS resources may be configured to be transmitted in different symbols based on the resourceType of the upper layer parameter SRS-ResourceSet. In this case, each SRS resource in the given SRS resource set may configure a single SRS port, and the SRS port for each SRS resource may be configured to be associated with different UE antenna ports. In contrast, when SRS transmission is configured aperiodic, two SRS resource sets, each consisting of 0 SRS resource sets or a total of 4 SRS resources, may be configured to be transmitted in different symbols of two different slots based on the resourceType of the upper layer parameter SRS-ResourceSet. In this case, the SRS port for each SRS resource in the two given SRS resource sets may be configured to be associated with different UE antenna ports.

(Example S4) As another example, for a terminal supporting 1T1R, 2T2R, or 4T4R, up to two SRS resource sets, each consisting of one SRS resource, can be configured for SRS transmission, and the number of SRS ports of each SRS resource can be set to 1, 2, or 4.

If the indicated terminal capability is 1T4R/2T4R, the terminal may expect that the same number of SRS ports (e.g., 1 or 2) will be configured for all SRS resources in the SRS resource set(s). In addition, if the indicated terminal capability is 1T2R, 2T4R, 1T4R, or 1T4R/2T4R, the terminal may not expect that one or more SRS resource sets configured for antenna switching purpose in the same slot will be configured or triggered. In addition, even if the indicated terminal capability is 1T1R, 2T2R, or 4T4R, the terminal may not expect that one or more SRS resource sets configured for antenna switching purpose in the same slot will be configured or triggered.

< SRS enhancement in Rel-17 MIMO >

The importance of SRS transmission of terminals to secure UL and DL channel estimation performance in NR TDD systems has increased. Accordingly, standardization was carried out in Rel-17 MIMO with the following three goals.

First, standardization was carried out with the goal of more flexibly controlling aperiodic SRS transmission according to the DL and UL slot ratios and traffic conditions of various TDD systems.

Second, NR terminals supporting DL rank 8 transmission must be equipped with at least 8 receiving antennas, but the SRS antenna changing transmission technique for estimating DL channels based on channel reciprocity in the NR TDD system only supports terminals with up to 4 receiving antennas. Therefore, Rel-17 standardized the technique to support the SRS antenna changing transmission technique for terminals equipped with more than 4 receiving antennas.

Third, standardization was carried out for the purpose of increasing the transmission coverage of SRS and increasing the capacity of SRS considering simultaneous access of multiple terminals.

A more flexible aperiodic SRS transmission triggering technique

Figure 2 is a diagram illustrating flexible aperiodic SRS transmission timing control.

In order to more flexibly control aperiodic SRS transmissions according to the DL and UL slot ratios and traffic conditions of various TDD systems in Rel-17 MIMO, the following two techniques are standardized.

First, a technique is introduced to dynamically control the slot offset value for aperiodic SRS transmission triggers via DCI. This is to solve the problem that the slot offset value is previously fixed semi-statically, which may result in significant delay in SRS transmission depending on DL and UL slot settings.

To this end, a new DCI field is defined that specifies one of multiple slot offset values set by an RRC message. In addition, the slot offset value indicated by the DCI field is standardized to be calculated based on available slots defined as uplink slots and slots composed of flexible symbols, thereby enabling flexible SRS transmission triggering with a small number of slot offset candidate values.

Second, we introduce a technique for triggering aperiodic SRS transmission without accompanying UL data transmission and CSI reporting. In the conventional method, SRS transmission could be triggered together with UL DCI only when PUSCH is allocated to trigger UL data and/or CSI reporting. It was difficult for a base station to estimate UL/DL channels by triggering SRS for a terminal in a situation where there is no UL data to transmit and aperiodic CSI reporting is not required. This technique is intended to solve the above-mentioned problems.

SRS antenna change transmission for terminals equipped with more than 4 receiving antennas

As described above, the SRS antenna change transmission technique supported in the Rel-15/16 NR system only considered terminals equipped with 4 receiving antennas. In Rel-17 MIMO, the SRS antenna change transmission method for terminals equipped with 6 receiving antennas and 8 receiving antennas was standardized. The extended antenna change transmission method supports the following combinations of the number of Nt transmitting antennas and the number of Nr receiving antennas.

Terminal with Nr=6: Nt=1, Nt=2, Terminal with Nr=8: Nt=1, Nt=2, Nt=4

The above SRS transmission can be transmitted within one slot, or across two or four slots.

SRS Coverage and Capacity Enhancement Techniques

Figure 3 is a diagram illustrating partial band SRS transmission.

To increase the coverage and capacity of SRS in Rel-17 MIMO, three major techniques were introduced.

First, the maximum number of repetitions of SRS was increased so that it can be utilized in systems requiring wider coverage. In Rel-15 and Rel-16, SRS could be repeatedly transmitted in up to 4 symbols within a slot, except in the case of positioning. In Rel-17 MIMO, SRS can be repeatedly transmitted in up to 14 symbols within a slot to secure wider SRS coverage. Specifically, SRS can be transmitted in 8, 10, 12, or 14 consecutive symbols within a slot.

Another is that SRS can be transmitted only in partial bands. For this purpose, the base station can set the resource block location where SRS transmission starts and the SRS transmission band to the terminal. For SRS transmission, the corresponding frequency location can also be hopped or fixed according to a set rule according to the SRS frequency hopping period. The introduction of this technique allows different terminals to simultaneously transmit SRS to the same base station in different partial bands, thereby increasing the capacity of SRS.

Finally, SRS with lower frequency density was supported. Except for the case of positioning in Rel-15/16, the frequency density of SRS supported was 1 RE per 2 RE or 1 RE per 4 RE. Accordingly, stable channel estimation performance could be secured in a frequency-selective channel environment, but there was a limit to securing SRS capacity. Therefore, a transmission technique that transmits SRS in 1 RE per 8 RE was additionally introduced in Rel-17 MIMO, thereby enabling SRS capacity to be increased in a frequency-nonselective channel environment.

In NR Rel-15 MIMO, SRS can be used for UL link adaptation (codebook/non-codebook), beam management, and DL CSI acquisition (antenna switching). In Rel-17 FeMIMO, standardization was carried out to increase the number of repetitions, introduce RPFS (RB-level Partial Frequency Sounding), and support comb value 8 in order to enhance the coverage and capacity of SRS.

In Rel-18, SRS was also standardized to support 8-port transmission, considering terminals capable of 8 Tx transmission. Comb offset hopping and cyclic shift hopping were introduced to improve the capacity and interference randomization performance of SRS.

As below, Rel-19 will perform SRS enhancement for terminals with 3 Tx antennas.

"Specify non-coherent UL codebook to facilitate 3-antenna-port codebook-based transmissions, without enhancement on UL full power transmission and without enhancement on SRS resource

Note: UL full power transmission mode 1 and 2 are not supported."

The uplink reference signal SRS has been used for DL CSI acquisition using channel reciprocity in TDD environment in addition to its original purpose of UL link adaptation since the LTE standard. One of the four "usages" of SRS in NR is "antenna switching" for DL CSI acquisition. In the case of actual market UEs, there are many implementations where the number of Tx chains and Rx chains is asymmetrical to reduce cost (e.g., the number of Rx chains including Rx antennas > the number of Tx chains). In order to perform sounding over a large number of Rx antennas using a small number of Tx chains, the SRS antenna switching operation through RF switching has been standardized (see SRS for 'antennaSwitching' above). This SRS antenna switching operation has been enhanced to xT6R/xT8R configuration for terminals with more than 4 Rx antennas in Rel-17, and to 8T8R configuration for 8Tx terminals in Rel-18. SRS enhancement for 3 Tx terminals is scheduled to be performed in Rel-18. There is a need for discussion on how SRS antenna switching of 3 Tx terminals will be performed.

Below, we propose a method to introduce a new 3 Tx SRS antenna switching by extending/enhancing the existing SRS antenna switching configuration, and a method to introduce a 3 Tx SRS antenna switching by combining the existing SRS antenna switching configuration (while performing only minimal enhancement).

Based on this background, this paper proposes a method for setting SRS antenna switching considering 3 Tx terminals of a base station and a subsequent terminal antenna switching SRS transmission operation.

In this document, '/' means 'and', 'or', or 'and/or' depending on the context.

In order to support 3-port SRS resources in this specification, the following methods may be considered.

Alt 1. A method of setting/indicating 3 CS values out of the 4 CS (cyclic shift) values set for legacy 4-port SRS resources for 3-port resources.

Alt 2. A method of setting/indicating 3 comb values out of the 4 comb values set for legacy 4-port SRS resources for 3-port resources.

Alt 3. A method of setting/indicating 3 comb/CS values out of 2 comb values and 2 CS values (total 4 comb/CS values) set for legacy 4-port SRS resource for 3-port resource.

Alt 4. Redefine 3-port SRS resource so that 3 CS values are assigned to 3 ports of the 3-port SRS resource.

Alt 5. Redefine 3-port SRS resource so that 3 comb values are assigned to 3 ports of the 3-port SRS resource.

Alt 6. A method of configuring a 3-port SRS resource by combining a legacy 2-port SRS resource and a 1-port SRS resource, or configuring a 3-port SRS resource by combining three legacy 1-port SRS resources.

Hereinafter, SRS resource transmission may mean SRS transmission on an SRS resource. Hereinafter, it is assumed that the upper layer parameter usage of the SRS resource set is set to 'antennaSwitching'. Hereinafter, port may be interpreted/replaced with an SRS port or an antenna port.

Proposal 1

A method of introducing a new 3 Tx SRS antenna switching by extending/enhancing the existing SRS antenna switching configuration can be considered.

1) Terminal supporting 3T3R

i. The base station can set one SRS resource set including one 3-port SRS resource for a 3T3R supporting terminal. The terminal can perform sounding for 3 Rx antennas by transmitting the 3-port SRS resource without switching.

2) Terminals supporting 3T4R

i. The base station may configure one SRS resource set including one 3-port SRS resource and one 1-port SRS resource for the 3T4R supporting terminal. The 3-port SRS resource and the 1-port SRS resource may correspond to mutually exclusive SRS ports. The meaning of mutually exclusive SRS ports in this specification will be described in more detail as follows. That two SRS resources correspond to mutually exclusive SRS ports may mean that SRS ports based on a first SRS resource (e.g., three SRS ports, ports 1000-1002) are different from SRS ports based on a second SRS resource (e.g., one SRS port, port 1003). As an example, the base station may configure a Y gap symbol as shown in Table 2 between transmission of the 3-port SRS resource and the 1-port SRS resource in consideration of the antenna switching time of the terminal. For example, the base station may schedule the resources considering the Y gap symbol.

ii. The base station may configure one SRS resource set including two 2-port SRS resources for the 3T4R supporting terminal. The two 2-port SRS resources may each correspond to a mutually exclusive SRS port. The base station may configure a Y gap symbol as shown in Table 2 between transmissions of the two 2-port SRS resources, considering the antenna switching time of the terminal. For example, the base station may schedule the resources considering the Y gap symbol.

iii. The base station can configure one SRS resource set including two 3-port SRS resources for the 3T4R supporting terminal. The two 3-port SRS resources include two SRS port(s) in common, and the remaining one port of each resource can correspond to a mutually exclusive SRS port, respectively. The base station can configure a Y gap symbol as shown in Table 2 between transmissions of the two 3-port SRS resources considering the antenna switching time of the terminal. For example, the base station may need to schedule the resources considering the Y gap symbol.

3) Terminals supporting 3T6R

i. The base station may configure one SRS resource set including two 3-port SRS resources for the 3T6R supporting terminal. The two 3-port SRS resources may each correspond to a mutually exclusive SRS port. The base station may configure a Y gap symbol as shown in Table 2 between transmissions of the two 3-port SRS resources, considering the antenna switching time of the terminal. For example, the base station may schedule the resources considering the Y gap symbol.

4) Terminals supporting 3T8R

i. The base station can configure one SRS resource set including two 3-port SRS resources and one 2-port SRS resource for the 3T8R supporting terminal. Among the three resources, the first 3-port SRS resource, the second 3-port SRS resource, and the 2-port SRS resource can correspond to mutually exclusive SRS ports. The base station can configure a Y gap symbol as shown in Table 2 between transmissions of the three resources considering the antenna switching time of the terminal. For example, the base station may need to schedule the resources considering the Y gap symbol.

ii. The base station can configure one SRS resource set including four 2-port SRS resources for the 3T8R supporting terminal. The four 2-port SRS resources can each correspond to a mutually exclusive SRS port. The base station can configure a Y gap symbol as shown in Table 2 between the transmission of the four 2-port SRS resources considering the antenna switching time of the terminal. For example, the base station may schedule the resources considering the Y gap symbol.

In the above proposal 1, the 3-port SRS resource can be composed of one or more SRS resources.

In Proposal 1, assuming that 3 Tx SRS resources are defined, we propose a method for configuring SRS antenna switching for 3 Tx terminals using 3 Tx SRS resources. By newly defining SRS antenna switching configuration for 3 Tx terminals, the terminals receive only minimum resources from the base station. The terminals can perform 3 Tx SRS antenna switching operation simply (with reduced delay) by utilizing the configured resources. In addition, in case of iii) of 2) above, if there is an SRS port commonly included in different SRS resource transmissions, it can be helpful in correcting phase errors, etc. when the different SRS resources are transmitted with a time difference in the time domain.

Proposal 2

A method to introduce 3 Tx SRS antenna switching by combining existing SRS antenna switching settings (with only minimal enhancement) can be considered.

1) Terminal supporting 3T3R

i. The base station can configure 2-port SRS resource and one 1-port SRS resource for a 3T3R supporting terminal. The two resources can be included in one SRS resource set or can be included in two SRS resource sets, respectively. The 2-port SRS resource and the 1-port SRS resource can correspond to mutually exclusive SRS ports. In the case of a terminal supporting 3T3R, since it is a terminal capable of transmitting 3 Tx antennas simultaneously, operations i) or ii) can be performed by the terminal. i) The 2-port SRS resource and the 1-port SRS resource can be transmitted simultaneously (using the same time/frequency resource). ii) Transmission can be performed by concatenating (at a symbol level) the 2-port SRS resource and the 1-port SRS resource without setting a Y gap symbol between transmissions.

ii. Similar to paragraph i above, the base station can configure three 1-port SRS resources for a 3T3R supporting terminal. The three resources can be included in one SRS resource set or can be included in three SRS resource sets respectively. The terminal can perform either i) or ii) operations. i) The three 1-port SRS resources can be transmitted simultaneously (using the same time/frequency resources). ii) Transmission can be performed by concatenating (at symbol level) the transmission of each resource without setting a Y gap symbol between transmissions.

iii. The base station can configure one SRS resource set including two 2-port SRS resources for the 3T3R supporting terminal. The two resources can be included in one SRS resource set or can be included in two SRS resource sets, respectively. The two 2-port SRS resources include one SRS port(s) in common, and the remaining one port of each resource can correspond to a mutually exclusive SRS port. The terminal can perform either i) or ii) operation. i) The two 2-port SRS resources can be transmitted simultaneously (using the same time/frequency resource). ii) Transmission can be performed by concatenating (at symbol level) transmission between the transmissions of each resource without setting a Y gap symbol.

2) Terminals supporting 3T4R

i. The base station can set two 2-port SRS resources for a 3T4R supporting terminal. The two resources can be included in one SRS resource set or can be included in two SRS resource sets, respectively. The two 2-port SRS resources can each correspond to a mutually exclusive SRS port. The base station can set a Y gap symbol as shown in Table 2 between transmissions of the two 2-port SRS resources, considering the antenna switching time of the terminal. For example, the base station may schedule the resources considering the Y gap symbol.

ii. Similar to the above paragraph i, the base station can configure four 1-port SRS resources for the 3T4R supporting terminal. The four resources can be included in one SRS resource set, or can be divided into two SRS resource sets, with three resources and one resource being included. The terminal can perform operations i) or ii). i) Three resources (belonging to the same SRS resource set) among the four 1-port SRS resources can be transmitted simultaneously (using the same time/frequency resources). ii) Transmission can be performed by concatenating (at symbol level) the three resources without setting a Y gap symbol between transmissions.

iii. Similar to the above paragraph i, the base station can configure one 2-port SRS resource and two 1-port SRS resources for the 3T4R supporting terminal. The three resources can be included in one SRS resource set, or two resources and one resource can be divided and included in two SRS resource sets. The terminal can perform operations i) or ii). i) Two resources among the three resources (belonging to the same SRS resource set) can be transmitted simultaneously (using the same time/frequency resources). ii) Transmission can be performed by concatenating (at the symbol level) the two resources without setting a Y gap symbol between transmissions.

3) Terminals supporting 3T6R

i. The base station can set three 2-port SRS resources for the 3T6R supporting terminal. The three resources can be included in one SRS resource set or can be included in three SRS resource sets, respectively. The three 2-port SRS resources can each correspond to a mutually exclusive SRS port. The base station can set a Y gap symbol as shown in Table 2 between transmissions of the three 2-port SRS resources, considering the antenna switching time of the terminal. For example, the base station may schedule the resources considering the Y gap symbol.

ii. The base station can configure six 1-port SRS resources for a 3T6R supporting terminal. The six resources can be included in one SRS resource set or three resources can be included in two SRS resource sets each. The terminal can perform operations i) or ii). i) Three resources among the six 1-port SRS resources (belonging to the same SRS resource set) can be transmitted simultaneously (using the same time/frequency resources). ii) Transmission can be performed by concatenating (at symbol level) the three resources without setting a Y gap symbol between transmissions.

4) Terminals supporting 3T8R

i. The base station can set four 2-port SRS resources for the 3T8R supporting terminal. The four resources can be included in one SRS resource set or can be included in four SRS resource sets, respectively. The four 2-port SRS resources can each correspond to a mutually exclusive SRS port. The base station can set a Y gap symbol as shown in Table 2 between transmissions of the four 2-port SRS resources, considering the antenna switching time of the terminal. For example, the base station may schedule the resources considering the Y gap symbol.

ii. The base station can configure eight 1-port SRS resources for the 3T8R supporting terminal. The eight resources can be included in one SRS resource set, or three or two SRS resources can be included in each of three SRS resource sets. For example, the first and second SRS resource sets can include three SRS resources, and the third SRS resource set can include two SRS resources. Operations i) or ii) can be performed by the terminal. i) Two or three resources (belonging to the same SRS resource set) among the eight 1-port SRS resources can be transmitted simultaneously (using the same time/frequency resource). ii) Transmission can be performed by concatenating (at a symbol level) two or three resources without setting a Y gap symbol between transmissions.

In the above proposal 2, a method of configuring one or more 4-port SRS resources as SRS resource configurations for supporting 3TyR terminals is proposed. As a specific embodiment, for a terminal supporting 3T6R, a base station can configure two 4-port SRS resources and schedule the two resources in TDM format. A method of transmitting only resources corresponding to three ports when each 4-port SRS resource is transmitted by the terminal may be considered. For example, since the two SRS resources correspond to different SRS ports, it may be necessary to configure a Y gap symbol between the two resources in consideration of antenna switching time. For example, since each of three ports is transmitted from two 4-port SRS resources, sounding for 6 Rx antennas can be performed in the 3T6R configuration. Examples related to SRS transmission based on three ports out of four ports are described in detail below.

In one embodiment, the terminal may transmit SRS by selecting three ports (e.g., ports 1000-1002) in ascending/descending order from the lowest/highest port index of the 4-port SRS resource. As an example of ascending port index, the terminal may transmit SRS based on three ports (e.g., ports 1000-1002) among four ports (e.g., ports 1000-1003). As an example of descending port index, the terminal may transmit SRS based on three ports (e.g., ports 1003, 1002, 1001) among four ports (e.g., ports 1000-1003). To put the above example differently, any one port (e.g. port 1003 or port 1000) other than the three ports determined in ascending/descending port index order can be muted or disabled.

In one embodiment, a terminal can transmit SRS by selecting three ports in ascending/descending order from the lowest/highest CS values of a 4-port SRS resource.

In one embodiment, a terminal can transmit an SRS by selecting three ports in ascending/descending order from the lowest/highest value (in the frequency domain) among the comb values of a 4-port SRS resource.

In one embodiment, a terminal can transmit an SRS by selecting three ports among two comb values and two CS values of a 4-port SRS resource.

In one embodiment, a base station can set one 4-port SRS resource for a terminal supporting 3T3R. The terminal can transmit only resources (e.g., symbols) corresponding to three ports according to the above-described rules. In more detail, the terminal can transmit SRS based on symbol(s) related to three ports among symbols based on the 4-port SRS resource.

In one embodiment, for a terminal supporting 3T8R, a base station can set three 4-port SRS resources. For two specific 4-port SRS resources, the terminal can transmit only the resources corresponding to three ports according to the above-determined rule (e.g., ascending/descending order of port index). For the remaining one 4-port SRS resource, the terminal can transmit only the resources corresponding to two ports by applying the above-determined rule.

The above embodiments are methods for enabling SRS antenna switching of a 3 Tx terminal by using/utilizing only some ports of a 4-port SRS resource. According to the embodiments, there is an advantage of enabling 3 Tx SRS antenna switching without the need to separately define a 3-port resource. In addition, there is an advantage of enabling resources corresponding to/corresponding to ports not used/utilized by the terminal in the 4-port SRS resource to be utilized for SRS scheduling of other terminals.

According to Proposal 2, the SRS resource setting for the existing 1TyR/2TyR is utilized/extended without utilizing the 3Tx SRS resource (3 port SRS resource). Specifically, Proposal 2 proposes a SRS antenna switching setting method for a 3 Tx terminal through a combination of legacy setting methods. There is an advantage in that the 3 Tx SRS antenna switching operation of the terminal can be supported by utilizing the existing RRC parameters without the need to newly define the SRS antenna switching setting for the 3 Tx terminal. However, more than one SRS resource setting may be required for a specific 3TyR operation. In addition, in case of iii) of the above 1), when there is an SRS port commonly included in different SRS resource transmissions, it can be helpful in correcting phase errors, etc. when the different SRS resources are transmitted with a time difference in the time domain.

Proposal 3

A method may be considered to perform SRS antenna switching configuration corresponding to a subset of a specific SRS UE capability report (e.g., xTyR) of the terminal.

First, we describe the existing operation based on UE capability (e.g., xTyR) related to antenna switching. The UE capability, xTyR, indicates that the UE is capable of transmitting SRS on x ports based on y antennas. The y antennas are based on all or a subset of the UE receive antennas.

After the Rel-15 SRS antenna switching standardization, a new antenna switching capability was added in the Rel-16 standardization to enable the base station to configure xTyR less than the number of Tx antennas of the terminal even though the terminal supports 2T2R, 2T4R, and 4T4R for more than 2 Tx terminals (i.e., supportedSRS-TxPortSwitch-v1610). This was done in consideration of flexibility in base station configuration and terminal power saving. The operation based on the UE capability (UE sounding procedure) and the upper layer parameters related to the UE capability (see Table 3) are examined in turn.

The UE sounding procedure for DL CSI acquisition is as follows.

If the upper layer parameter usage in the SRS-ResourceSet of the UE is set to 'antennaSwitching', the UE shall support the indicated UE capability supportedSRS-TxPortSwitch ('t1r2' for 1T2R, 't1r1-t1r2' for 1T=1R/1T2R, 't2r4' for 2T4R, 't1r4' for 1T4R, 't8r8' for 8T8R, 't1r1-t1r2-t1r4' for 1T=1R/1T2R/1T4R, 't1r4-t2r4' for 1T4R/2T4R, 't1r1-t1r2-t2r2-t2r4' for 1T=1R/1T2R/2T=2R/2T4R, Only one of the configurations can be set depending on the configuration ('t1r1-t1r2-t2r2-t1r4-t2r4' for 1T=1R/1T2R/2T=2R/1T4R/2T4R, 't1r1' for 1T=1R, 't2r2' for 2T=2R, 't1r1-t2r2' for 1T=1R/2T=2R, 't4r4' for 4T=4R, or 't1r1-t2r2-t4r4' for 1T=1R/2T=2R/4T=4R). Or the UE may set only one of the configurations according to the indicated UE capability supportedSRS-TxPortSwitchBeyond4Rx ('t1r1' for 1T=1R, 't2r2' for 2T=2R, 't1r2' for 1T2R, 't4r4' for 4T=4R, 't2r4' for 2T4R, 't1r4' for 1T4R, 't2r6' for 2T6R, 't1r6' for 1T6R, 't4r8' for 4T8R, 't2r8' for 2T8R, 't1r8' for 1T8R). Here, the configurations mean the setting of SRS resource set/SRS resource defined per UE capability, such as the examples S0~S4 described above. As an example of 4T8R, 0, 1, or 2 SRS resource sets can be set in the terminal. Each SRS resource set has two SRS resources transmitted in different symbols. Each SRS resource in a given set consists of four SRS ports. The SRS ports of a resource in a given set are associated with different UE antenna ports.

In a 3TyR configuration that can be supported by a 3Tx terminal (e.g., SRS resource/SRS resource set configuration for 3T6R), the UE capability reporting method for a subset configuration corresponding to/associated with lower capability than the corresponding configuration is described in detail below.

1) A terminal supporting 3T3R can report a capability combination as follows (at least one of the candidates) for subset configuration in SRS antenna switching capability related to 3 Tx terminals.

i. {1T1R, 1T2R, 1T3R, 2T2R, [2T3R], 3T3R}

2) A terminal supporting 3T4R can report a capability combination as follows (at least one of the candidates) for subset configuration in SRS antenna switching capability related to a 3 Tx terminal.

i. {1T1R, 1T2R, [1T3R], 1T4R, 2T2R, [2T3R], 2T4R, 3T3R, 3T4R}

3) A terminal supporting 3T6R can report a capability combination as follows (at least one of the candidates) for subset configuration in SRS antenna switching capability related to 3 Tx terminals.

i. {1T1R, 1T2R, [1T3R], 1T4R, 1T6R, 2T2R, [2T3R], 2T4R, 2T6R, 3T3R, 3T4R, 3T6R}

4) A terminal supporting 3T8R can report a capability combination as follows (at least one of the candidates) for subset configuration in SRS antenna switching capability related to 3 Tx terminals.

i. {1T1R, 1T2R, [1T3R], 1T4R, 1T6R, 1T8R, 2T2R, [2T3R], 2T4R, 2T6R, 2T8R, 3T3R, 3T4R, 3T6R, 3T8R}

Problem 1

The reason why it was decided to standardize the transmission/reception method to support 3 Tx terminals in the current Rel-18 MIMO is because of market usage. Specifically, the maximum number of Tx antennas supported by terminals currently distributed in the market is 2, and there is not enough space to increase the number of Tx antennas infinitely in hand-held terminals. As described above, the development of terminals equipped with 3 Tx antennas is realistic, but the number of terminal Tx antennas supported by the standard is only 1/2/4/8. For the above reasons, standardization for supporting 3 Tx antenna terminals was conducted. Here, the Tx antenna and Tx chain structure for hand-held terminals may be limited. For example, some of the three antennas may share an RF chain including a power amplifier. For example, RF switching for antenna switching may not be possible between a specific antenna and some antennas among the three antennas (because the transmission panels are different or physically separated). In Proposal 4, we propose a technique to operate 3 Tx SRS antenna switching under these structural limitations.

Proposal 4

In cases where RF chains are shared between specific antennas and some antennas in a 3 Tx terminal, a method supporting 3 Tx SRS antenna switching can be considered.

1) In a 3 Rx antenna terminal, two Tx/Rx antennas share an RF chain and an independent RF chain is implemented in the remaining one Tx/Rx antenna.

i. 3T3R setup

- The base station can set 2-port SRS resource and 1-port SRS resource for 3T3R supporting terminal (when receiving a terminal report that RF chain is shared between specific antennas in the terminal implementation) similar to 1)-i of the proposal 2. The terminal supporting 3T3R is a terminal that can perform transmission based on 3 Tx antennas simultaneously. Operation of i) or ii) can be performed by the terminal. i) The 2-port SRS resource and the 1-port SRS resource can be transmitted simultaneously (using the same time/frequency resource). ii) Transmission can be performed by concatenating (at symbol level) the 2-port SRS resource and the 1-port SRS resource transmission without setting a Y gap symbol.

ii. 2T3R setting

- The base station may set 2-port SRS resource and 1-port SRS resource for 2T3R supporting terminal (if a terminal report is received that RF chain is shared between specific antennas in the terminal implementation). The 2-port SRS resource and the 1-port SRS resource correspond to mutually exclusive SRS ports. 2-ports associated/corresponding to two Tx/Rx antennas sharing RF chain may be mapped to the 2-port SRS resource. The base station may set Y gap symbol as shown in Table 2 between transmission of the 2-port SRS resource and the 1-port SRS resource considering the antenna switching time of the terminal. For example, the base station may need to schedule the resources considering the Y gap symbol.

Or/and, the 2-port SRS resource and the 1-port SRS resource correspond to mutually exclusive SRS ports. The 2-port SRS resource may have 2 ports associated/corresponding to one of the two Tx/Rx antennas sharing an RF chain and one Tx/Rx antenna configured with the remaining independent RF chain. In this case, since antenna switching is not required between the 2-port SRS resource and the 1-port SR resource (since 1 port of the 2-port resource and 1 port of the 1-port resource share an RF chain), the two 2-port SRS resources can be transmitted concatenatedly (at a symbol level) without setting a Y gap symbol between transmissions.

- (Alternatively,) the base station may configure three 1-port SRS resources for the 2T3R supporting terminal (if the base station receives a terminal report that RF chain is shared between specific antennas in the terminal implementation). The three 1-port SRS resources correspond to mutually exclusive SRS ports. No gap symbol configuration may be required between transmissions of 1-port SRS resources associated with two Tx/Rx antennas sharing the RF chain (since the terminal can transmit through two antennas simultaneously). Additionally/or, the 1-port SRS resources associated with the two Tx/Rx antennas sharing the RF chain may be transmitted simultaneously (using the same time/frequency resources). On the other hand, the base station may configure a Y gap symbol as shown in Table 2 by considering the antenna switching time of the terminal between transmission of the 1-port SRS resources associated with the two Rx antennas and transmission of the 1-port SRS resource associated with the remaining one Tx/Rx antenna. For example, the base station may schedule the resources considering the Y gap symbol.

iii. 1T3R setting

The base station can configure three 1-port SRS resources for the 1T3R supporting terminal (if the base station receives a terminal report that an RF chain is shared between specific antennas in the terminal implementation). The three 1-port SRS resources correspond to mutually exclusive SRS ports, and no gap symbol configuration may be required between transmissions of the 1-port SRS resources associated with the two Tx/Rx antennas sharing the RF chain (since the terminal can perform simultaneous transmission based on the two antennas). In addition/or, the 1-port SRS resources associated with the two Tx/Rx antennas sharing the RF chain can be transmitted simultaneously (using the same time/frequency resources). On the other hand, the base station can configure a Y gap symbol as shown in Table 2 by considering the antenna switching time of the terminal between transmission of the 1-port SRS resources associated with the two Rx antennas and transmission of the 1-port SRS resource associated with the remaining one Tx/Rx antenna. For example, the base station may schedule the resources considering the Y gap symbol.

2) In a 4 Rx antenna terminal, two Tx/Rx antennas share an RF chain and the remaining two Tx/Rx antennas share an RF chain.

i. 3T4R setup

- The base station can configure two 2-port SRS resources for the 3T4R supporting terminal (if the base station receives a terminal report that RF chain is shared between specific antennas in the terminal implementation). The two 2-port SRS resources each correspond to a mutually exclusive SRS port. Each 2-port SRS resource can have a 2-port associated/corresponding to one of the first two Tx/Rx antennas sharing the RF chain and one of the second two Tx/Rx antennas sharing the RF chain mapped. In this case, since antenna switching is not required between the two 2-port SRSs (since each two ports of the 2-port resource and each two ports of the other 2-port resource share the RF chain), the two 2-port SRS resources can be configured to be transmitted concatenatedly (at a symbol level) without configuring a Y gap symbol between transmissions.

ii. 2T4R setting

- The same base station/terminal operation as above i can be performed.

iii. 1T4R setting

- The base station can configure four 1-port SRS resources for the 1T4R supporting terminal (if the base station receives a terminal report that RF chain is shared between specific antennas in the terminal implementation). The four 1-port SRS resources correspond to mutually exclusive SRS ports. No gap symbol configuration may be required between transmissions of 1-port SRS resources associated with two Tx/Rx antennas sharing the RF chain (since the terminal can transmit through two antennas simultaneously). In addition/or, the 1-port SRS resources associated with two Tx/Rx antennas sharing the RF chain can be transmitted simultaneously (using the same time/frequency resources). On the other hand, the base station can configure a Y gap symbol as shown in Table 2 above by considering the antenna switching time of the terminal between transmission of 1-port SRS resources associated with two Rx antennas sharing the RF chain and transmission of 1-port SRS resources associated with two Tx/Rx antennas sharing the remaining RF chain. For example, the base station may schedule the resources considering the Y gap symbol.

3) Similar to the above operations 1 and 2, 3 Tx SRS antenna switching of 6 Rx/8 Rx antenna terminals can be performed. For example, transmission of multiple SRS resources related to Tx/Rx antennas sharing a Tx chain can be concatenated (at symbol level) without setting a Y gap symbol, or the multiple SRS resources can be transmitted simultaneously (by utilizing the same time/frequency resources).

In the above proposal 4, multiple SRS resources related to ports sharing the same RF chain can be included in a specific SRS resource set. Or/and a connection relationship can be established/defined between multiple SRS resources related to ports sharing the same RF chain through signaling (such as RRC/MAC-CE). In more detail, if SRS resources are included in different SRS resource sets or the connection relationship is not established between SRS resources, it may mean that ports related to the corresponding SRS resources are related to different RF chains (not sharing an RF chain) and a Y gap symbol needs to be established between transmissions of the corresponding SRS resources.

Proposal 4 utilizes the fact that Y gap symbols are not required between multiple SRS resources for antenna switching in a specific terminal implementation, or that the multiple SRS resources can be transmitted simultaneously. Proposal 4 has the advantage that the delay required for a terminal to complete transmission of a specific antenna switching configuration can be reduced.

Problem 2

In the above proposals, it can be assumed that SRS resources with different numbers of ports are transmitted in TDM. For example, 1-port SRS resources and 2-port SRS resources can be transmitted in TDM. For example, 2-port SRS resources and 3-port SRS resources can be transmitted in TDM.

According to the SRS power control operation below, the SRS transmission power is determined according to the SRS transmission occasion, and (the linear power value) is equally split for each port in the corresponding transmission occasion. Accordingly, a power imbalance problem may occur in which the power of each Rx antenna that performed sounding for antenna switching is not constant. For example, it can be assumed that a 1-port SRS resource and a 2-port SRS resource are transmitted in TDM for antenna switching transmission for 3 Rx antennas. For the 1-port SRS resource, P_SRS,b,f,c is determined by the power control parameters set for the SRS resource set to which the corresponding resource is set, and the terminal transmits the SRS using the determined values (without splitting since it is a 1-port resource). On the other hand, for the 2-port SRS resource, P_SRS,b,f,c (same as the set) is determined by the power control parameters set for the SRS resource set (same as the set) to which the corresponding resource is set. A value corresponding to 1/2 of the linear value of the determined value is allocated to each port. Accordingly, a power imbalance problem occurs. Proposal 5 proposes a method to solve the above problem 2.

First, we describe the existing operation related to the transmission power of SRS.

For SRS,

의 선형 값

을 SRS 전송을 위한 각 심볼에 대해 구성된 안테나 포트에 걸쳐 균등하게 분할한다(if a UE is provided tdm for an SRS resource with 8 ports in an SRS resource set with usage 'codebook' or 'antennaSwitching', the UE splits a linear value

of the transmit power

on active UL BWP

of carrier

of serving cell

equally across the configured antenna ports on each symbol for SRS transmission).- If tdm is provided for an SRS resource with 8 ports in an SRS resource set with usage of 'codebook' or 'antennaSwitching' to the UE, the UE transmits power at the active UL BWP b of carrier f of serving cell c.

Linear value of

splits the SRS resource evenly across the configured antenna ports for each symbol for SRS transmission (if a UE is provided tdm for an SRS resource with 8 ports in an SRS resource set with usage 'codebook' or 'antennaSwitching', the UE splits a linear value

of the transmit power

on active UL BWP

of carrier

of serving cell

equally across the configured antenna ports on each symbol for SRS transmission).

의 선형 값

을 SRS를 위해 구성된 안테나 포트에 걸쳐 균등하게 분할한다(else, a UE splits a linear value

of the transmit power

on active UL BWP

of carrier

of serving cell

equally across the configured antenna ports for SRS).- Otherwise, the UE transmits power at the active UL BWP b of carrier f of serving cell c.

Linear value of

splits the SRS signal evenly across the antenna ports configured for it (else, a UE splits a linear value

of the transmit power

on active UL BWP

of carrier

of serving cell

equally across the configured antenna ports for SRS).

을 다음과 같이 결정한다(If a UE transmits SRS based on a configuration by SRS-ResourceSet on active UL BWP

of carrier

of serving cell

using SRS power control adjustment state with index

, the UE determines the SRS transmission power

in SRS transmission occasion

as).When a UE transmits an SRS on an active UL BWP b of carrier f of serving cell c using an SRS power control adjustment state with index l, the UE shall adjust the SRS transmission power at SRS transmission opportunity i according to the configuration of SRS-ResourceSet.

is determined as follows (If a UE transmits SRS based on a configuration by SRS-ResourceSet on active UL BWP

of carrier

of serving cell

using SRS power control adjustment state with index

, the UE determines the SRS transmission power

in SRS transmission occasion

as).

[dbm]

[dbm]

Proposal 5

Below, we examine a method for solving the power imbalance problem, such as problem 2 above, when SRS resources with different numbers of ports are transmitted in TDM (for 3 Tx SRS antenna switching).

1) Embodiment 1: SRS resources transmitted in TDM may be assumed as a single SRS transmission occasion. As a specific example, a terminal may assume a plurality of SRS resources (configured for 3-port transmission) for transmission based on a specific single antenna switching configuration (e.g., xTyR configuration) or/and 3-port SRS transmission as a single SRS transmission occasion. Or/and the assumption for the single SRS transmission occasion may be agreed/specified between the base station/terminal. For example, if 2-port SRS resource and 1-port SRS resource are utilized for 3T3R antenna switching transmission, (corresponding resources are included in the same SRS resource set) P_SRS,b,f,c values for the two SRS resources may be defined/determined for a single SRS transmission occasion i. (Linear values of) the corresponding P_SRS,b,f,c values may be evenly divided for 2-port + 1-port = 3-port.

2) Embodiment 2: To solve problem 2, the existing operation of SRS port-specific power splitting can be extended and applied. Specifically, for transmission based on a specific single antenna switching configuration (e.g., xTyR configuration) or/and multiple SRS resources (configured for 3-port transmission) for 3-port SRS transmission, the terminal can evenly split the transmission power per port. This SRS power control operation can be defined or configured by the base station. For example, the following base station/terminal assumptions can be promised/specified.

의 선형 값

을 SRS 전송을 위한 구성된 3개 안테나 포트들에 걸쳐 균등하게 분할한다(if a UE is provided [3port] for SRS resource(s) with 3 ports in an SRS resource set with usage 'codebook' or 'antennaSwitching', the UE splits a linear value

of the transmit power

on active UL BWP

of carrier

of serving cell

equally across the configured three antenna ports for SRS transmission).- If [3port] is provided for SRS resource(s) with 3 ports in the SRS resource set whose usage is 'codebook' or 'antennaSwitching', the UE shall transmit power at the active UL BWP b of carrier f of serving cell c.

Linear value of

splits SRS resource(s) evenly across the configured 3 antenna ports for SRS transmission (if a UE is provided [3port] for SRS resource(s) with 3 ports in an SRS resource set with usage 'codebook' or 'antennaSwitching', the UE splits a linear value

of the transmit power

on active UL BWP

of carrier

of serving cell

equally across the configured three antenna ports for SRS transmission).

- In the above, [3port] may be an example of a configuration for at least one 3-port SRS resource(s). For example, [3port] being provided to a UE may mean that parameters/information related to SRS transmission based on 3 ports are configured/instructed to the UE.

3) Example 3: The terminal can perform power allocation for each SRS port by the following procedure.

Step 1: For each of the multiple SRS resources (configured for 3-port transmission) for transmission based on a specific single antenna switching configuration (e.g., xTyR configuration) and/or 3-port SRS transmission, the UE determines the power for each SRS transmission occasion as before.

Step 2: The terminal calculates the minimum value P_min among the powers per SRS port determined in Step 1. The terminal finally sets/applies the powers per port of the plurality of SRS resources to the P_min.

Through the above proposal 5, power is equally allocated to each SRS port related to antenna switching in SRS resources set for a specific SRS antenna switching configuration, thereby solving the power imbalance problem.

In the above proposals 1 to 4, the Y gap symbol may be a value that increases from the Y values in Table 2 according to the sub-carrier spacing. For example, as the sub-carrier spacing increases to 240/480/960 KHz, a separate Y value (proportionally increased) may be set/defined.

In the above proposals 1 to 4, the fact that multiple SRS resources can be transmitted simultaneously (using the same time/frequency resources) may mean that the following operations i) or ii) are performed. i) The base station configures multiple SRS resources to the terminal in the same symbol. At this time, each SRS resource may be configured to have a different CS/Comb value (so as to correspond to/map to mutually exclusive port(s)). ii) The base station configures multiple SRS resources to the terminal in the same symbol. At this time, each SRS resource may be configured to have a non-overlapped SRS PRB location. In the case of the above i), even if the multiple SRS resources are configured with the same FDRA parameters such as C_SRS, B_SRS, etc., the multiple SRS resources are transmitted using (orthogonal/quasi-orthogonal) resources corresponding to different ports, so that the resources can be transmitted without collision. Methods such as i) and ii) have the advantage that the base station can perform channel estimation for multiple SRS ports based on a specific single symbol.

The embodiments of the above proposals 1 to 5 can operate in certain combinations.

Below, we examine signaling procedures based on the embodiments described above.

An example of a terminal (or base station) operation based on at least one of the embodiments described above (e.g. at least one of Proposals 1 to 5) is as follows.

1) The terminal (base station) receives (transmits) SRS-related setting information.

The above configuration information may include configuration for SRS resource(s) within a specific SRS resource set (of codebook and/or antennaSwitching usage) based on Proposals 1 to 5.

2) The terminal (base station) transmits (receives) SRS according to P/SP/AP-SRS transmission setting/activation/instruction.

The terminal transmits the SRS resource set (including one or more SRS resources) configured/activated/indicated by RRC/MAC CE/DCI based on the settings of Proposal 1 to Proposal 5. Transmitting the SRS resource (set) means transmitting the SRS based on the SRS resource (set).

The terminal allocates power per SRS port based on Proposal 5.

In terms of implementation, the operations of the base station/terminal according to the embodiments described above (e.g., operations based on at least one of Proposals 1 to 5) can be processed by the device of FIG. 6 described below (e.g., processor (110, 210) of FIG. 6).

In addition, the operations of the base station/terminal according to the above-described embodiments (e.g., operations based on at least one of proposals 1 to 5) may be stored in a memory (e.g., 140, 240 of FIG. 6) in the form of commands/programs (e.g., instructions, executable codes) for driving at least one processor (e.g., 110, 210 of FIG. 6).

The embodiments described below are specifically described with reference to FIGS. 4 and 5 in terms of the operation of the terminal and the base station. The methods described below are distinguished only for the convenience of explanation, and it goes without saying that some components of one method may be substituted for some components of another method or may be applied in combination with each other.

FIG. 4 is a flowchart illustrating a method according to one embodiment of the present specification.

Referring to FIG. 4, a method according to one embodiment of the present specification includes a step of receiving configuration information (S410) and a step of transmitting SRS based on at least one SRS resource set (S420).

In S410, the terminal receives configuration information from the base station. Based on the configuration information, at least one Sounding Reference Signal (SRS) resource set related to antenna switching is configured.

For example, the at least one SRS resource set may be based on SRS resource set(s) having the higher layer parameter usage set to antennaSwitching.

For example, the above configuration information may be based on SRS-Config in Table 1.

For example, the configuration information may include i) a list of one or more SRS resource sets (e.g., srs-ResourceSetToAddModList) and ii) a list of one or more SRS resources (e.g., srs-ResourceToAddModList). An SRS resource set may include at least one SRS resource. A configuration for an SRS resource set may include a list of SRS resource ID(s) representing the at least one SRS resource (e.g., srs-ResourceIdList).

For example, the configuration information may include information related to a configuration/operation based on at least one of the above-described proposals 1 to 5. As a specific example, the configuration information may include information related to proposal 2. The configuration information may include information/parameters related to SRS transmission based on three of the four ports. As a specific example, the configuration information may include information related to proposal 5. The configuration information may include information related to determination of SRS transmission power based on three ports.

In S420, the terminal transmits an SRS to the base station based on at least one SRS resource set.

For example, the SRS may be transmitted in different symbols based on a plurality of SRS resources within the at least one SRS resource set. As a specific example, the SRS may be transmitted in different symbols (e.g., two symbols) based on two SRS resources within one SRS resource set. As a specific example, the SRS may be transmitted in different symbols based on SRS resource(s) of each of the two SRS resource sets.

For example, the number of ports set for each of the plurality of SRS resources may be the same or different. As a specific example, the number of ports set for the first SRS resource among the two SRS resources (e.g., 1, 2, 4, or 8) may be the same or different from the number of ports set for the second SRS resource (e.g., 1, 2, 4, or 8).

For example, the number of ports set for each of the plurality of SRS resources may be the same. In this case, the power control operation may be performed in the same manner as before. The transmission power is evenly distributed across the SRS ports based on one symbol (or each symbol among the plurality of symbols). Specifically, the linear value of the transmission power for the SRS may be evenly distributed across the ports of each SRS resource of each SRS resource set in the symbol.

When multiple SRS resources having different numbers of ports are transmitted in different symbols, a power imbalance problem such as problem 2 described above may occur. Embodiments for solving this problem are described in detail below.

In one embodiment, based on the number of ports set for each of the plurality of SRS resources being different, the transmission power associated with each port of one of the plurality of SRS resources may be the same. This embodiment may be based on Proposal 5.

Below, a detailed explanation is given assuming that the number of the above multiple SRS resources is 2.

It can be assumed that the number of ports set in the first SRS resource among two SRS resources is 4, and the number of ports set in the second SRS resource is 2. The transmission power (or the linear value of the transmission power) associated with each port among the four ports of the first SRS resource can be equal to the transmission power (or the linear value of the transmission power) associated with each port among the two ports of the second SRS resource. In the above example, the number of ports (4, 2) of each SRS resource and the number (2) of the plurality of SRS resources are assumed for the convenience of explanation. It is obvious that even if the number of ports and the total number of SRS resources are different from the above example, it is included in the technical idea of the present embodiment.

According to the above embodiment, even if the number of ports set for each of the plurality of SRS resources is the same or different, the transmission power (linear value of transmission power) for each port is controlled identically. Therefore, the operation related to the number of ports for each SRS resource described above can be expressed again as follows.

The number of ports set for each of the above plurality of SRS resources may be the same or different. The transmission power (or linear value of the transmission power) associated with each port of one of the above plurality of SRS resources may be the same. Based on the different number of ports set for each of the above plurality of SRS resources, the SRS transmission power may be determined based on one of the following embodiments.

In one embodiment, the plurality of SRS resources may be associated with a same SRS transmission occasion. The transmission power for the SRS may be determined based on the same SRS transmission occasion. This embodiment may be based on embodiment 1 of proposal 5.

In one embodiment, the transmit power for the SRS may be equally split across ports based on the plurality of SRS resources in the different symbols. This embodiment may be based on embodiment 2 of proposal 5.

In one embodiment, the lowest transmission power among the port-specific transmission powers determined for the plurality of SRS resources may be applied to the ports of the plurality of SRS resources. Hereinafter, a case in which the number of the plurality of SRS resources is 2 will be described as an example. Transmission power may be determined for each of the first SRS resource and the second SRS resource. A linear value of the determined transmission power may be equally split across the ports of each of the first SRS resource and the second SRS resource. In this case, the port-specific transmission powers described above may be based on i) a linear value (a first value) of the transmission power distributed/allocated to one of the ports of the first SRS resource and ii) a linear value (a second value) of the transmission power distributed/allocated to one of the ports of the second SRS resource. A smallest value among the first value and the second values may be applied as the transmission power of each of the ports based on the two SRS resources. This embodiment may be based on Embodiment 3 of Proposal 5.

Below, we will look at an example of UE capability related to antenna switching of a terminal (e.g., 3Tx UE).

In one embodiment, the at least one SRS resource set can be configured based on UE capability. The UE capability, xTyR, can indicate that the UE is capable of transmitting SRS on x ports based on y antennas. For example, the y antennas can be based on all or a subset of UE receive antennas.

In one embodiment, based on the UE capability being 3TyR: each SRS resource in the at least one SRS resource set may include four antenna ports. Furthermore, in each SRS resource, the SRS may be transmitted based on at least one antenna port among the four antenna ports. The present embodiment may be based on Proposal 2. For example, each SRS resource may be based on the 4-port SRS resource described above. The 4-port SRS resource may mean an SRS resource in which the upper layer parameter nrofSRS-Ports indicating the number of ports is set to ports4.

For example, based on the UE capability being 3T3R or 3T6R, the at least one antenna port may be three antenna ports. The UE capability being 3T3R or 3T6R may be indicated based on a higher layer parameter (e.g., supportedSRS-TxPortSwitch or supportedSRS-TxPortSwitchBeyond4Rx) set to 't3r3' or 't3r6'.

As a concrete example, for 3T6R, 0, 1 or 2 SRS resource sets can be configured. Each SRS resource set can include two SRS resources transmitted in different symbols. Each SRS resource in a given set (SRS resource set) can include four ports, and one of the four ports is disabled. The ports of each SRS resource in the SRS resource set are associated with different UE antenna ports. When two SRS resource sets are configured, two SRS resources based on the two SRS resource sets are transmitted in different symbols of different slots.

For example, the three antenna ports may be based on three antenna ports (e.g., ports 1000-1002) among the four antenna ports (e.g., ports 1000-1003) based on the ascending order of antenna port indices. As a specific example, port 1003 among ports 1000-1003 may be disabled.

According to the above-described embodiment, the antenna switching operation of the 3Tx UE (e.g., 3TyR-based operation) can be performed through the existing defined SRS resource (4-port SRS resource). Therefore, the implementation complexity required to support the antenna switching operation of the 3Tx UE (e.g., 3TyR-based operation) can be reduced by minimizing the enhancement of the existing defined terminal/base station operation.

The operations based on S410 to S420 described above can be implemented by the device of Fig. 6. For example, the terminal (200) can control one or more transceivers (230) and/or one or more memories (240) to perform the operations based on S410 to S420.

The embodiments described below are specifically described in terms of base station operation.

S510 to S520 described below correspond to S410 to S420 described in Fig. 4. Considering the above correspondence relationship, redundant descriptions are omitted. That is, the specific description of the base station operation described below can be replaced with the description/example of Fig. 4 corresponding to the operation.

FIG. 5 is a flowchart illustrating a method according to another embodiment of the present specification.

Referring to FIG. 5, a method according to another embodiment of the present specification includes a step of transmitting configuration information (S510) and a step of receiving an SRS based on at least one SRS resource set (S520).

In S510, the base station transmits configuration information to the terminal. Based on the configuration information, at least one Sounding Reference Signal (SRS) resource set related to antenna switching is configured.

In S520, the base station receives an SRS from the terminal based on at least one SRS resource set.

For example, the SRS may be received in different symbols based on a plurality of SRS resources within the at least one SRS resource set.

The operations based on S510 to S520 described above can be implemented by the device of Fig. 6. For example, the base station (100) can control one or more transceivers (130) and/or one or more memories (140) to perform the operations based on S510 to S520.

Below, a device to which an embodiment of the present specification can be applied (a device that implements a method/operation according to an embodiment of the present specification) is described with reference to FIG. 6.

FIG. 6 is a drawing showing the configuration of a first device and a second device according to an embodiment of the present specification.

The first device (100) may include a processor (110), an antenna unit (120), a transceiver (130), and a memory (140).

The processor (110) performs baseband-related signal processing and may include an upper layer processing unit (111) and a physical layer processing unit (115). The upper layer processing unit (111) may process operations of a MAC layer, an RRC layer, or higher layers. The physical layer processing unit (115) may process operations of a PHY layer. For example, when the first device (100) is a base station device in base station-terminal communication, the physical layer processing unit (115) may perform uplink reception signal processing, downlink transmission signal processing, etc. For example, when the first device (100) is a first terminal device in terminal-to-terminal communication, the physical layer processing unit (115) may perform downlink reception signal processing, uplink transmission signal processing, sidelink transmission signal processing, etc. In addition to performing baseband-related signal processing, the processor (110) may also control the overall operation of the first device (100).

The antenna unit (120) may include one or more physical antennas, and when it includes multiple antennas, it may support MIMO transmission and reception. The transceiver (130) may include an RF (Radio Frequency) transmitter and an RF receiver. The memory (140) may store information processed by the processor (110), and software, an operating system, applications, etc. related to the operation of the first device (100), and may also include components such as a buffer.

The processor (110) of the first device (100) may be configured to implement operations of the base station in base station-to-terminal communication (or operations of the first terminal device in terminal-to-terminal communication) in the embodiments described in the present disclosure.

The second device (200) may include a processor (210), an antenna unit (220), a transceiver (230), and a memory (240).

The processor (210) performs baseband-related signal processing and may include an upper layer processing unit (211) and a physical layer processing unit (215). The upper layer processing unit (211) may process operations of a MAC layer, an RRC layer, or higher layers. The physical layer processing unit (215) may process operations of a PHY layer. For example, when the second device (200) is a terminal device in base station-terminal communication, the physical layer processing unit (215) may perform downlink reception signal processing, uplink transmission signal processing, etc. For example, when the second device (200) is a second terminal device in terminal-to-terminal communication, the physical layer processing unit (215) may perform downlink reception signal processing, uplink transmission signal processing, sidelink reception signal processing, etc. In addition to performing baseband-related signal processing, the processor (210) may also control the overall operation of the second device (210).

The antenna unit (220) may include one or more physical antennas, and when it includes multiple antennas, it may support MIMO transmission and reception. The transceiver (230) may include an RF transmitter and an RF receiver. The memory (240) may store information processed by the processor (210), and software, an operating system, applications, etc. related to the operation of the second device (200), and may also include components such as a buffer.

The processor (210) of the second device (200) may be configured to implement operations of a terminal in base station-to-terminal communication (or operations of a second terminal device in terminal-to-terminal communication) in the embodiments described in the present disclosure.

In the operation of the first device (100) and the second device (200), the matters described for the base station and the terminal (or the first terminal and the second terminal in the terminal-to-terminal communication) in the examples of the present disclosure can be applied equally, and redundant descriptions are omitted.

Here, the wireless communication technology implemented in the device (100, 200) of the present disclosure may include LTE, NR, and 6G, as well as Narrowband Internet of Things (NB-IoT) for low-power communication. For example, the NB-IoT technology may be an example of LPWAN (Low Power Wide Area Network) technology, and may be implemented with standards such as LTE Cat NB1 and/or LTE Cat NB2, and is not limited to the above-described names.

Additionally or alternatively, the wireless communication technology implemented in the device (100, 200) of the present disclosure may perform communication based on LTE-M technology. For example, the LTE-M technology may be an example of LPWAN technology and may be called by various names such as eMTC (enhanced Machine Type Communication). For example, the LTE-M technology may be implemented by at least one of various standards such as 1) LTE CAT 0, 2) LTE Cat M1, 3) LTE Cat M2, 4) LTE non-BL (non-Bandwidth Limited), 5) LTE-MTC, 6) LTE Machine Type Communication, and/or 7) LTE M, and is not limited to the above-described names.

Additionally or alternatively, the wireless communication technology implemented in the device (100, 200) of the present disclosure may include at least one of ZigBee, Bluetooth, and Low Power Wide Area Network (LPWAN) considering low-power communication, and is not limited to the above-described names. For example, ZigBee technology can create PAN (personal area networks) related to small/low-power digital communication based on various standards such as IEEE 802.15.4, and may be called by various names.

Claims (15)

In terms of method, A step of receiving configuration information from a base station, wherein at least one Sounding Reference Signal (SRS) resource set related to antenna switching is configured based on the configuration information; and A step of transmitting an SRS to the base station based on at least one SRS resource set; comprising: The above SRS is transmitted in different symbols based on a plurality of SRS resources within the at least one SRS resource set, A method characterized in that the transmission power associated with each port of one of the plurality of SRS resources is the same, based on the number of ports set for each of the plurality of SRS resources being different. In the first paragraph, The above multiple SRS resources are associated with the same SRS transmission occasion, A method characterized in that the transmission power for the above SRS is determined based on the same SRS transmission opportunity. In the first paragraph, The transmission power for the above SRS is in the different symbols A method characterized in that the plurality of SRS resources are equally split across ports. In the first paragraph, A method characterized in that the lowest transmission power among the port-specific transmission powers determined for the plurality of SRS resources is applied to the ports of the plurality of SRS resources. In the first paragraph, The number of ports set for each of the above multiple SRS resources is the same, A method characterized in that the linear value of the transmission power for the above SRS is evenly distributed across the ports of each SRS resource of each SRS resource set in a symbol. In the first paragraph, The above at least one SRS resource set is set based on UE capability, A method characterized in that the UE capability, which is xTyR, indicates that the terminal is capable of transmitting SRS on x ports based on y antennas. In Article 6, A method characterized in that the y antennas are based on all or a subset of UE receive antennas. In Article 6, Based on the above UE capability of 3TyR: Each SRS resource in the above at least one SRS resource set includes four antenna ports, A method characterized in that, in each SRS resource, the SRS is transmitted based on at least one antenna port among the four antenna ports. In Article 8, Based on the above UE capability, which is 3T3R or 3T6R: A method, wherein said at least one antenna port is three antenna ports. In Article 9, A method characterized in that the above three antenna ports are three antenna ports based on the ascending order of antenna port indices among the above four antenna ports. At the terminal, One or more transmitters and receivers; one or more processors; and comprising one or more memories connected to said one or more processors and storing instructions; A terminal characterized in that the instructions, based on being executed by the one or more processors, cause the terminal to perform all steps of the method according to any one of claims 1 to 10. In a device comprising one or more memories and one or more processors functionally connected to the one or more memories, A device characterized in that said one or more memories store instructions that cause said device to perform all steps of a method according to any one of claims 1 to 10, based on being executed by said one or more processors. In one or more non-transitory computer-readable storage media storing instructions, One or more non-transitory computer-readable storage media characterized in that the instructions executable by one or more processors cause a terminal to perform all steps of a method according to any one of claims 1 to 10. In terms of method, A step of transmitting configuration information to a terminal, wherein at least one Sounding Reference Signal (SRS) resource set related to antenna switching is configured based on the configuration information; and A step of receiving an SRS from the terminal based on at least one SRS resource set; comprising: The above SRS is received in different symbols based on a plurality of SRS resources within the at least one SRS resource set, A method characterized in that the transmission power associated with each port of one of the plurality of SRS resources is the same, based on the number of ports set for each of the plurality of SRS resources being different. At the base station, One or more transmitters and receivers; one or more processors; and comprising one or more memories connected to said one or more processors and storing instructions; A base station characterized in that said instructions, based on being executed by said one or more processors, cause said base station to perform all steps of the method according to claim 14.

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