KR20210011328A - Method and apparatus for channel state information feedback in communication system supporting sidelink communication - Google Patents

Abstract

Disclosed are a method and an apparatus for channel state information (CSI) feedback in a communication system supporting sidelink communication. An operating method of a first terminal comprises: a step of transmitting CSI request information requesting transmission of a CSI report to a second terminal; a step of receiving a CSI report #1 for a sidelink between the first terminal and the second terminal from the second terminal in a sidelink channel; and a step of transmitting one or more CSI reports between the CSI report #1 and a CSI report #2 for a communication link between the first terminal and a base station to the base station in an uplink channel. Therefore, the performance of a communication system can be improved.

Description

Method and device for CSI feedback in a communication system supporting sidelink communication {METHOD AND APPARATUS FOR CHANNEL STATE INFORMATION FEEDBACK IN COMMUNICATION SYSTEM SUPPORTING SIDELINK COMMUNICATION}

The present invention relates to a sidelink communication technology in a communication system, and more particularly, to a CSI (channel state information) feedback technology for sidelink communication.

In order to process rapidly increasing radio data, a frequency band higher than the frequency band of LTE (long term evolution) (or LTE-A) (eg, a frequency band of 6 GHz or less) (eg, a frequency band of 6 GHz or higher) A communication system using (for example, a new radio (NR) communication system) is being considered. The NR communication system can support not only a frequency band of 6 GHz or less but also a frequency band of 6 GHz or more, and can support various communication services and scenarios compared to the LTE communication system. For example, the usage scenario of the NR communication system may include enhanced Mobile BroadBand (eMBB), Ultra Reliable Low Latency Communication (URLLC), and Massive Machine Type Communication (mMTC).

Meanwhile, the LTE communication system and the NR communication system may support vehicle to everything (V2X) communication, and V2X communication may be performed according to a sidelink communication protocol. Sidelink communication for V2X may be performed based on a unicast method, a multicast method, a groupcast method, and/or a broadcast method. When sidelink communication is performed based on a unicast method, a feedback method of a hybrid automatic repeat request (HARQ) response (eg, HARQ-ACK (acknowlegdement)) for sidelink communication, and channel state information (CSI) You will need a feedback method, etc. However, the feedback method of the HARQ response and the feedback method of the CSI for sidelink communication in the NR communication system are not explicitly defined.

An object of the present invention for solving the above problems is to provide a method and apparatus for a hybrid automatic repeat request (HARQ) response and feedback of channel state information (CSI) in a communication system supporting sidelink communication. Have.

In order to achieve the above object, a method of operating a first terminal according to a first embodiment of the present invention includes transmitting CSI request information requesting transmission of a CSI report to a second terminal, the first terminal and the second Receiving CSI report #1 for sidelink between UEs from the second UE in a sidelink channel, and at least one CSI from among the CSI report #1 and CSI report #2 for the communication link between the first UE and the base station And transmitting reports to the base station in an uplink channel.

Here, the priority of the CSI report #1 may be determined according to the type of the sidelink channel through which the CSI report #1 is transmitted, and the sidelink channel may be PSFCH or PSSCH.

Here, the priority of the CSI report #1 may be determined according to a transmission method of the CSI report #1, and the transmission method may be a triggering transmission method, a semi-fixed transmission method, or a periodic transmission method.

Here, the priority of the CSI report #1 may be determined according to a sidelink communication method between the first terminal and the second terminal, and the sidelink communication method may be a unicast method, a groupcast method, or a broadcast method. I can.

Here, the one or more CSI reports may be selected according to the priority of the CSI report #1 and the priority of the CSI report #2, and the uplink channel may be a PUCCH or a PUSCH.

Here, the priority of the sidelink may be set differently from the priority of the communication link, the priority of the CSI report #1 may be determined in consideration of the priority of the sidelink, and the priority of the CSI report #2 The priority may be determined in consideration of the priority of the communication link.

Here, when the cell index associated with the sidelink is the same as the cell index associated with the communication link, the priority of the CSI report #1 and the priority of the CSI report #2 are the priority between the sidelink and the communication link. Can be determined irrespective of

Here, the operating method of the first terminal may further include transmitting data to the second terminal, and the HARQ response to the data and the CSI report #1 may be received in the same sidelink channel.

Here, the CSI request information and the scheduling information for the data may be included in the SCI transmitted from the first terminal to the second terminal.

The operation method of the second terminal according to the second embodiment of the present invention to achieve the above object, the step of receiving a CSI-RS from the first terminal in a sidelink between the first terminal and the second terminal, the CSI -Generating a plurality of CSI reports based on the RS, selecting one or more CSI reports according to priority among the plurality of CSI reports, and the one or more CSI reports to the first terminal in a sidelink channel And transmitting.

Here, the priorities of the plurality of CSI reports may be determined according to the type of the sidelink channel through which each CSI report is transmitted, and the sidelink channel may be PSFCH or PSSCH.

Here, the priorities of the plurality of CSI reports may be determined according to a transmission method of each CSI report, and the transmission method may be a triggering transmission method, a semi-fixed transmission method, or a periodic transmission method.

Here, the priorities of the plurality of CSI reports may be determined according to a sidelink communication method between the first terminal and the second terminal, and the sidelink communication method may be a unicast method, a groupcast method, or a broadcast method. I can.

Here, the operation method of the second terminal further includes receiving an SCI including scheduling information for data from the first terminal, and receiving the data from the first terminal based on the scheduling information The HARQ response for the data and the one or more CSI reports may be transmitted on the same sidelink channel.

The first terminal according to the third embodiment of the present invention for achieving the above object includes a processor, a memory in electronic communication with the processor, and instructions stored in the memory, wherein the instructions are executed by the processor. In this case, the instructions are that the first terminal transmits a CSI-RS in the sidelink between the first terminal and the second terminal, and the CSI report #1 for the CSI-RS is transmitted from the second terminal in a sidelink channel. It receives, and operates to cause transmission of one or more CSI reports from the CSI report #1 and the CSI report #2 for the communication link between the first terminal and the base station to the base station in an uplink channel.

Here, the priority of the CSI report #1 may be determined according to the type of the sidelink channel through which the CSI report #1 is transmitted, and the sidelink channel may be PSFCH or PSSCH.

Here, the priority of the CSI report #1 may be determined according to a transmission method of the CSI report #1, and the transmission method may be a triggering transmission method, a semi-fixed transmission method, or a periodic transmission method.

Here, the priority of the CSI report #1 may be determined according to a sidelink communication method between the first terminal and the second terminal, and the sidelink communication method may be a unicast method, a groupcast method, or a broadcast method. I can.

Here, the one or more CSI reports may be selected according to the priority of the CSI report #1 and the priority of the CSI report #2, and the uplink channel may be a PUCCH or a PUSCH.

Here, the priority of the sidelink may be set differently from the priority of the communication link, the priority of the CSI report #1 may be determined in consideration of the priority of the sidelink, and the priority of the CSI report #2 The priority may be determined in consideration of the priority of the communication link.

According to the present invention, a transmitting terminal can transmit a channel state information-reference signal (CSI-RS) to a receiving terminal, and the receiving terminal can generate a plurality of CSI reports based on the CSI-RS. The receiving terminal may transmit one or more CSI reports selected according to priority among a plurality of CSI reports to the transmitting terminal. The transmitting terminal may transmit one or more CSI reports selected according to priority among CSI report(s) for sidelink and CSI report(s) for downlink to the base station. Therefore, CSI feedback for the sidelink can be efficiently performed, and the performance of the communication system can be improved.

1 is a conceptual diagram showing a first embodiment of a communication system.
2 is a block diagram showing a first embodiment of a communication node constituting a communication system.
3 is a conceptual diagram showing a first embodiment of a communication system supporting sidelink communication.
4 is a flowchart illustrating a first embodiment of a CSI feedback method in a communication system supporting sidelink communication.

In the present invention, various modifications may be made and various embodiments may be provided, and specific embodiments will be illustrated in the drawings and described in detail. However, this is not intended to limit the present invention to a specific embodiment, it is to be understood to include all changes, equivalents, and substitutes included in the spirit and scope of the present invention.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. These terms are used only for the purpose of distinguishing one component from another component. For example, without departing from the scope of the present invention, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element. The term and/or includes a combination of a plurality of related listed items or any of a plurality of related listed items.

When a component is referred to as being "connected" or "connected" to another component, it is understood that it may be directly connected or connected to the other component, but other components may exist in the middle. Should be. On the other hand, when a component is referred to as being "directly connected" or "directly connected" to another component, it should be understood that there is no other component in the middle.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present application, terms such as "comprise" or "have" are intended to designate the presence of features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, but one or more other features. It is to be understood that the presence or addition of elements or numbers, steps, actions, components, parts, or combinations thereof, does not preclude in advance.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms as defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and should not be interpreted as an ideal or excessively formal meaning unless explicitly defined in the present application. Does not.

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings. In describing the present invention, in order to facilitate an overall understanding, the same reference numerals are used for the same elements in the drawings, and duplicate descriptions for the same elements are omitted.

A communication system to which embodiments according to the present invention are applied will be described. The communication system to which the embodiments according to the present invention are applied is not limited to the contents described below, and the embodiments according to the present invention can be applied to various communication systems. Here, the communication system may be used with the same meaning as a communication network.

1 is a conceptual diagram showing a first embodiment of a communication system.

Referring to FIG. 1, a communication system 100 includes a plurality of communication nodes 110-1, 110-2, 110-3, 120-1, 120-2, 130-1, 130-2, 130-3, 130-4, 130-5, 130-6). A plurality of communication nodes are 4G communication (e.g., long term evolution (LTE), LTE-A (advanced)), 5G communication (e.g., new radio) specified in the 3rd generation partnership project (3GPP) standard. ), etc. 4G communication may be performed in a frequency band of 6 GHz or less, and 5G communication may be performed in a frequency band of 6 GHz or more as well as a frequency band of 6 GHz or less.

For example, for 4G communication and 5G communication, a plurality of communication nodes may include a code division multiple access (CDMA)-based communication protocol, a wideband CDMA (WCDMA)-based communication protocol, a time division multiple access (TDMA)-based communication protocol, Frequency division multiple access (FDMA)-based communication protocol, OFDM (orthogonal frequency division multiplexing)-based communication protocol, Filtered OFDM-based communication protocol, CP (cyclic prefix)-OFDM-based communication protocol, DFT-s-OFDM (discrete) Fourier transform-spread-OFDM)-based communication protocol, OFDMA (orthogonal frequency division multiple access)-based communication protocol, SC (single carrier)-FDMA-based communication protocol, NOMA (Non-orthogonal Multiple Access), GFDM (generalized frequency) Division multiplexing) based communication protocol, FBMC (filter bank multi-carrier) based communication protocol, UFMC (universal filtered multi-carrier) based communication protocol, SDMA (Space Division Multiple Access) based communication protocol can be supported. .

In addition, the communication system 100 may further include a core network. When the communication system 100 supports 4G communication, the core network may include a serving-gateway (S-GW), a packet data network (PDN)-gateway (P-GW), a mobility management entity (MME), and the like. have. When the communication system 100 supports 5G communication, the core network may include a user plane function (UPF), a session management function (SMF), an access and mobility management function (AMF), and the like.

Meanwhile, a plurality of communication nodes 110-1, 110-2, 110-3, 120-1, 120-2, 130-1, 130-2, 130-3, 130- constituting the communication system 100 4, 130-5, 130-6) Each may have the following structure.

2 is a block diagram showing a first embodiment of a communication node constituting a communication system.

Referring to FIG. 2, the communication node 200 may include at least one processor 210, a memory 220, and a transmission/reception device 230 connected to a network to perform communication. In addition, the communication node 200 may further include an input interface device 240, an output interface device 250, and a storage device 260. Each of the components included in the communication node 200 may be connected by a bus 270 to perform communication with each other.

However, each of the components included in the communication node 200 may be connected through an individual interface or an individual bus centering on the processor 210 instead of the common bus 270. For example, the processor 210 may be connected to at least one of the memory 220, the transmission/reception device 230, the input interface device 240, the output interface device 250, and the storage device 260 through a dedicated interface. .

The processor 210 may execute a program command stored in at least one of the memory 220 and the storage device 260. The processor 210 may mean a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which methods according to embodiments of the present invention are performed. Each of the memory 220 and the storage device 260 may be configured with at least one of a volatile storage medium and a nonvolatile storage medium. For example, the memory 220 may be formed of at least one of a read only memory (ROM) and a random access memory (RAM).

Referring back to FIG. 1, the communication system 100 includes a plurality of base stations 110-1, 110-2, 110-3, 120-1, 120-2, and a plurality of terminals 130- 1, 130-2, 130-3, 130-4, 130-5, 130-6). Base stations (110-1, 110-2, 110-3, 120-1, 120-2) and terminals (130-1, 130-2, 130-3, 130-4, 130-5, 130-6) The containing communication system 100 may be referred to as an “access network”. Each of the first base station 110-1, the second base station 110-2, and the third base station 110-3 may form a macro cell. Each of the fourth base station 120-1 and the fifth base station 120-2 may form a small cell. The fourth base station 120-1, the third terminal 130-3, and the fourth terminal 130-4 may belong to the cell coverage of the first base station 110-1. The second terminal 130-2, the fourth terminal 130-4, and the fifth terminal 130-5 may belong to the cell coverage of the second base station 110-2. The fifth base station 120-2, the fourth terminal 130-4, the fifth terminal 130-5, and the sixth terminal 130-6 may belong within the cell coverage of the third base station 110-3. have. The first terminal 130-1 may belong to the cell coverage of the fourth base station 120-1. The sixth terminal 130-6 may belong to the cell coverage of the fifth base station 120-2.

Here, each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 is a NodeB, an evolved NodeB, gNB, and a base transceiver station (BTS). ), a radio base station, a radio transceiver, an access point, an access node, and the like. Each of the plurality of terminals 130-1, 130-2, 130-3, 130-4, 130-5, and 130-6 is a user equipment (UE), a terminal, an access terminal, and a mobile device. It may be referred to as a mobile terminal, a station, a subscriber station, a mobile station, a portable subscriber station, a node, a device, and the like.

Meanwhile, each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may operate in different frequency bands or may operate in the same frequency band. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may be connected to each other through an ideal backhaul link or a non-ideal backhaul link, , Information can be exchanged with each other through an ideal backhaul link or a non-ideal backhaul link. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may be connected to the core network through an ideal backhaul link or a non-ideal backhaul link. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 transmits a signal received from the core network to the corresponding terminal 130-1, 130-2, 130-3, 130 -4, 130-5, 130-6), and the signal received from the corresponding terminal (130-1, 130-2, 130-3, 130-4, 130-5, 130-6) Can be transferred to.

In addition, each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 transmits MIMO (e.g., single user (SU)-MIMO, multi-user (MU)- MIMO, massive MIMO, etc.), coordinated multipoint (CoMP) transmission, carrier aggregation (CA) transmission, transmission in an unlicensed band, direct communication between terminals (device to device communication, D2D) (or, ProSe ( proximity services)). Here, each of the plurality of terminals 130-1, 130-2, 130-3, 130-4, 130-5, and 130-6 is a base station 110-1, 110-2, 110-3, 120-1 , 120-2) and operations supported by the base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may be performed. For example, the second base station 110-2 may transmit a signal to the fourth terminal 130-4 based on the SU-MIMO scheme, and the fourth terminal 130-4 may transmit a signal to the fourth terminal 130-4 by the SU-MIMO scheme. A signal may be received from the second base station 110-2. Alternatively, the second base station 110-2 may transmit a signal to the fourth terminal 130-4 and the fifth terminal 130-5 based on the MU-MIMO method, and the fourth terminal 130-4 And each of the fifth terminal 130-5 may receive a signal from the second base station 110-2 by the MU-MIMO method.

Each of the first base station 110-1, the second base station 110-2, and the third base station 110-3 may transmit a signal to the fourth terminal 130-4 based on the CoMP scheme, and The terminal 130-4 may receive signals from the first base station 110-1, the second base station 110-2, and the third base station 110-3 by the CoMP method. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 has terminals 130-1, 130-2, 130-3, and 130-4 belonging to their cell coverage. , 130-5, 130-6) and the CA method can transmit and receive signals. Each of the first base station 110-1, the second base station 110-2, and the third base station 110-3 can control D2D between the fourth terminal 130-4 and the fifth terminal 130-5. And, each of the fourth terminal 130-4 and the fifth terminal 130-5 may perform D2D under the control of the second base station 110-2 and the third base station 110-3, respectively. .

Next, methods of transmitting a hybrid automatic repeat request (HARQ) response and a channel state information (CSI) report in a communication system supporting sidelink communication in a communication system will be described. Even when a method performed in the first communication node (for example, transmission or reception of a signal) among communication nodes is described, the second communication node corresponding thereto is a method corresponding to the method performed in the first communication node (e.g. For example, signal reception or transmission) may be performed. That is, when the operation of the terminal is described, the corresponding base station may perform an operation corresponding to the operation of the terminal. Conversely, when the operation of the base station is described, the terminal corresponding thereto may perform an operation corresponding to the operation of the base station.

In the following embodiments, signaling may be one or a combination of two or more of higher layer signaling, medium access control (MAC) signaling, and physical (PHY) signaling. Higher layer signaling may refer to a procedure for transmitting and receiving system information (eg, a master information block (MIB), a system information block (SIB)) and/or a radio resource control (RRC) message. MAC signaling may mean a transmission/reception procedure of MAC CE (control information). PHY signaling may refer to a transmission/reception procedure of control information (eg, downlink control information (DCI), uplink control information (UCI), sidelink control information (SCI)).

A message used for higher layer signaling may be referred to as a higher layer signaling message, a message used for MAC signaling may be referred to as a MAC signaling message, and a message used for PHY signaling may be referred to as a PHY signaling message. I can. In the following embodiments, "a base station (eg, a serving base station) sets specific information to the terminal" or "specific information is set to the terminal" means "the base station sends a signaling message including specific information to the terminal. It may mean "an operation to transmit to."

Channels used in sidelink communication include a physical sidelink shared channel (PSSCH), a physical sidelink control channel (PSCCH), a physical sidelink discovery channel (PSCCH), a physical sidelink broadcast channel (PSBCH), and a physical sidelink feedback channel (PSFCH). can do. The sidelink signal may be a synchronization signal and a reference signal used for sidelink communication. For example, the synchronization signal may be a synchronization signal/physical broadcast channel (SS/PBCH) block, a sidelink synchronization signal (SLSS), a primary sidelink synchronization signal (PSSS), a secondary sidelink synchronization signal (SSSS), and the like. Reference signals are CSI-RS (channel state information-reference signal), DM-RS (demodulation-reference signal), PT-RS (phase tracking-reference signal), CRS (cell specific reference signal), SRS (sounding reference signal) , A discovery reference signal (DRS), or the like. In the following embodiments, the sidelink signal may be used to include a sidelink signal and a sidelink channel.

3 is a conceptual diagram showing a first embodiment of a communication system supporting sidelink communication.

Referring to FIG. 3, the communication system may include a base station 310, a first terminal 321, and a second terminal 322. The first terminal 321 and/or the second terminal 322 may be located within the coverage of the base station 310. Alternatively, the first terminal 321 and/or the second terminal 322 may be located outside the coverage of the base station 310. The first terminal 321 and/or the second terminal 322 may be connected to a base station. Each of the first terminal 321 and the second terminal 322 may operate in a radio resource control (RRC) idle state, an RRC inactive state, or an RRC connected state. The base station 310, the first terminal 321, and the second terminal 322 may be configured in the same or similar to the communication node 200 shown in FIG. 2.

V2X (vehicle to everything) communication service is a PC5 interface between the first terminal 321 and the second terminal 322 and / or the base station 310 and a terminal (for example, a first terminal 321, a second terminal ( 322)) may be provided through the Uu interface. The PC5 interface can be used for V2X sidelink (SL) communication. V2X SL communication may mean V2X communication performed according to a sidelink communication method. In the following embodiments, sidelink communication may mean V2X SL communication. V2X SL communication is not only when the terminal (for example, the first terminal 321, the second terminal 322) belongs to the coverage of the base station 310, but also the terminal (for example, the first terminal 321, 2 This can be applied even when the terminal 322 does not belong to the coverage of the base station 310.

Meanwhile, the resource allocation operation for V2X SL communication may be performed according to two modes. When the first mode (hereinafter referred to as "mode 1") is used, a terminal operating in an RRC connected state may request resource allocation to a base station (eg, a serving base station to which the terminal is connected), and the base station Information on the resources allocated according to the request of can be transmitted to the terminal, and the terminal can perform V2X SL communication using the resources allocated by the base station. When the second mode (hereinafter referred to as "mode 2") is used, the terminal can autonomously secure resources (eg, sidelink resources). The sidelink resource may be a resource used for sidelink communication. Mode 2 may be used when a resource region or a resource pool is previously set in the terminal. In embodiments, the resource region may refer to a resource pool, and the resource pool may refer to a resource region.

The terminal may perform a sensing operation for a sidelink resource (eg, a listen before talk (LBT) operation), and may select a specific sidelink resource according to a result of the sensing operation. The terminal may select the sidelink resource again. Depending on the result of the sensing operation, a plurality of sidelink resources may be reserved. The number of sidelink resources that can be simultaneously reserved by the terminal may be limited. The maximum number of sidelink resources that can be simultaneously reserved by the terminal may be set by one or a combination of two or more of higher layer signaling, MAC signaling, and PHY signaling. The terminal may perform sidelink communication (eg, V2X SL communication) by using one or more sidelink resources among a plurality of reserved sidelink resources. One terminal can help when another terminal selects a sidelink resource. In addition, one terminal can directly allocate sidelink resources to another terminal.

The terminal may report its own geographic location information to the base station (eg, serving base station). The geographic location information may be information indicating a zone to which the terminal belongs (eg, zone ID). The geographic location may be associated with a sidelink resource area (eg, a sidelink resource pool). The relationship (eg, mapping relationship) between the geographic location and the sidelink resource region may be established by one or two or more of higher layer signaling, MAC signaling, and PHY signaling. The relationship between the geographic location and the sidelink resource area may be used in mode 2 (eg, when the terminal autonomously selects the sidelink resource). A terminal located outside the coverage of the base station may use a preset relationship (eg, a mapping relationship between a geographic location and a sidelink resource region).

The terminal may perform sidelink communication (eg, V2X SL communication) on one or more carriers. Sidelink communication may be supported by networks of various operators (eg, public land mobile network (PLMN)). One or more SL SPS (semi-persistant scheduling) may be configured, and one or more SL SPSs among a plurality of configured SL SPSs may be activated or deactivated. SL SPS may be configured by a base station (eg, serving base station) and/or a terminal. One or more SL SPSs may be configured by one or a combination of two or more of higher layer signaling, MAC signaling, and PHY signaling. The base station (eg, serving base station) may transmit information indicating activation or deactivation of the SL SPS to the terminal. Information indicating activation or deactivation of the SL SPS may be indicated by MAC signaling (eg, MAC CE) and/or PHY signaling (eg, DCI).

The terminal may transmit UE assistance information including other information (eg, information for sidelink communication) to the base station (eg, serving base station). The transmission method of UE assistance information may be configured by one or a combination of two or more of higher layer signaling, MAC signaling, and PHY signaling. The UE assistance information may include traffic characteristic information, and the traffic characteristic information may be used by a base station (eg, a serving base station) when activating SL SPS. For example, the traffic characteristic information includes a period of SL SPS, timing offset, L2 ID of a receiving terminal (e.g., a destination UE (DUE)) in sidelink communication, a logical channel identifier (LCID), and a traffic pattern. It may include the size of the transport block derived from (eg, the maximum size). The timing offset may be set in units of symbols, slots, or subframes. Here, the timing offset may be set based on a system frame number (SFN) 0.

The sidelink resource region may be defined in one or more frequencies. Information on the sidelink resource region set at a frequency other than the serving frequency may be broadcast from the base station through system information. Alternatively, the base station may transmit a separate message (eg, a dedicated message, a UE-specific message) including information on the sidelink resource region set at a frequency other than the serving frequency to each terminal. Alternatively, information on the sidelink resource region set at a frequency other than the serving frequency may be preset in the technical standard. That is, information on the sidelink resource region set in a frequency other than the serving frequency may be preset in the terminal.

The base station may allocate sidelink resource(s) to the terminal. For example, the base station may set one or more carriers to the terminal. Here, different carriers may be configured in the terminal. The base station may set different carrier(s) for each receiving terminal in a transmitting terminal (eg, a source UE (SUE)). Different carrier(s) configured in the transmitting terminal may be used for data packet duplication. The transmitting terminal may be a terminal that transmits data (eg, sidelink data), and the receiving terminal may be a terminal that receives data.

Sidelink communication and uplink communication performed on the same frequency resource(s) may overlap in the time domain. In this case, sidelink communication may be performed prior to uplink communication according to priority. Alternatively, uplink communication may be performed prior to sidelink communication according to priority. The priority may be set in the UE by one or a combination of two or more of higher layer signaling, MAC signaling, and PHY signaling. Alternatively, the priority may be predefined in the technical standard. That is, the terminal may know the priority in advance.

[CSI feedback multiplexing method in sidelink communication]

4 is a flowchart illustrating a first embodiment of a CSI feedback method in a communication system supporting sidelink communication.

Referring to FIG. 4, the communication system may include a base station, a transmitting terminal (SUE), and a receiving terminal (DUE). The base station illustrated in FIG. 4 may be the base station 310 illustrated in FIG. 3, and the transmitting terminal illustrated in FIG. 4 may be the first terminal 321 illustrated in FIG. 3, and the receiving terminal illustrated in FIG. 4 May be the second terminal 322 shown in FIG. 3. The base station, the first terminal, and the second terminal may be configured in the same or similar to the communication node 200 shown in FIG. 2.

The terminal may perform a measurement operation on a reference signal (eg, CSI-RS) received from the base station and/or other terminal, and may feed back a CSI report that is a result of the measurement operation on the reference signal. For example, the UE may transmit a CSI report to a base station (eg, a serving base station) through a physical uplink control channel (PUCCH) and/or a physical uplink shared channel (PUSCH). The UE may transmit a CSI report to another UE through PSSCH and/or PSCCH. CSI report may mean a message, signal, or information including CSI. CSI may include one or more of a channel quality indicator (CQI), a precoding matrix indicator (PMI), and a rank indicator (RI). CSI may include CQI, PMI, and RI as well as other information.

A base station (eg, a serving base station) may request transmission of a CSI report for sidelink communication from terminals (eg, a transmitting terminal and a receiving terminal) performing sidelink communication. The base station may request transmission of a CSI report for sidelink communication from the transmitting terminal through the PDCCH to which the SL-DCI is mapped (S401). That is, information for requesting CSI report (hereinafter referred to as "CSI request information") may be transmitted from the base station to the transmitting terminal through the PDCCH (eg, SL-DCI). The SL-DCI may be a DCI including information for sidelink communication, and the PDCCH to which the SL-DCI is mapped may be a PDCCH used for transmission of SL-DCI.

The transmitting terminal can obtain the SL-DCI from the base station by performing a monitoring operation on the PDCCH, and can check the CSI request information included in the SL-DCI. Alternatively, the CSI request information may be received through the PDCCH separately from SL-DCI. That is, the CSI request information may not be included in the SL-DCI. The transmitting terminal may request transmission of a CSI report for sidelink communication from the receiving terminal through the PSCCH and/or PSSCH to which the SCI is mapped (S402). CSI request information may be included in SCI. Alternatively, the CSI request information may be transmitted through PSCCH and/or PSSCH separately from SCI. That is, the CSI request information may not be included in the SCI.

SCI may include "1 ^st -stage SCI" or "1 ^st -stage SCI and 2 ^nd -stage SCI". 1 ^st -stage SCI may be transmitted through PSCCH, and 2 ^nd -stage SCI may be transmitted through PSSCH. The CSI request information may be included in 1 ^st -stage SCI and/or 2 ^nd -stage SCI. 1 ^st -stage SCI priority (priority) information, frequency resource allocation (frequency resource assignment) information, time resource allocation information, resource reservation period (resource reservation period) information, DMRS pattern information, the 2 ^nd -stage SCI format information, It may include one or more information elements from among beta_offset indicators, the number of DMRS ports, and modulation and coding scheme (MCS) information.

Details 2 ^nd -stage SCI is HARQ processor ID (identifier), RV (redundancy version), the source (source) ID, the destination (destination) ID, CSI request (request) information, zone (zone) ID, and a communication range request ( Communication range requirement) may include one or more information elements. In addition, SCI (eg, 1 ^st -stage SCI and / or 2 ^nd -stage SCI) is information indicating PSFCH resources for HARQ feedback (eg, frequency resource allocation information, time resource allocation information) and/ Alternatively, information for transmission of HARQ feedback may be further included.

Meanwhile, the receiving terminal may acquire SCI from the transmitting terminal by performing a monitoring operation on the PSCCH and/or PSSCH, and may check CSI request information included in the SCI. Alternatively, the CSI request information may be received through PSCCH and/or PSSCH separately from SCI. The transmitting terminal may transmit a CSI-RS (eg, CSI-RS for sidelink communication) to the receiving terminal (S403). If necessary, the transmitting terminal may transmit data (eg, SL-SCH (shared channel)) to the receiving terminal or other terminal(s). Data may be transmitted in a unicast method, a multicast method, a groupcast method, or a broadcast method.

The receiving terminal may receive the CSI-RS from the transmitting terminal, and may generate one or more CSI reports based on the received CSI-RS. The receiving terminal may transmit one or more CSI reports to the transmitting terminal (S404). When a plurality of CSI reports for the sidelink are generated, the receiving terminal generates one or more CSI reports (eg, one or more CSI reports having a relatively high priority) among a plurality of CSI reports according to priority. It can be selected and one or more selected CSI reports can be transmitted to the transmitting terminal. The priority of the CSI report may be determined based on Equation 1 or Equation 2 to be described later. The operation of determining the priority of the CSI report and the operation of selecting the CSI report based on the priority may be performed based on embodiments to be described later. The CSI report(s) may be transmitted from the receiving terminal to the transmitting terminal using PSSCH and/or PSFCH. PSSCH may be used for transmission of CSI report(s). In order to support this operation, the transmitting terminal may transmit information of the PSSCH used by the receiving terminal (eg, a channel reserved by the transmitting terminal) to the receiving terminal. Accordingly, the receiving terminal can transmit the CSI report(s) to the transmitting terminal using the PSSCH reserved by the transmitting terminal.

The transmitting terminal may receive the CSI report(s) for the sidelink from the receiving terminal. In addition, the transmitting terminal may generate CSI report(s) based on the CSI-RS received from the base station. That is, CSI report(s) for a communication link (eg, downlink) between the transmitting terminal and the base station may be generated. The transmitting terminal may select one or more CSI reports from CSI report(s) for the communication link and CSI report(s) for the sidelink. One or more CSI reports may be selected according to the priority of each CSI report. The priority of the CSI report may be determined based on Equation 1 or Equation 2 to be described later. The operation of determining the priority of the CSI report and the operation of selecting the CSI report based on the priority may be performed based on embodiments to be described later.

The transmitting terminal may transmit the CSI report(s) to the base station using PUCCH and/or PUSCH (S405). The CSI report(s) transmitted in step S405 may be CSI report(s) selected by the transmitting terminal according to priority. For example, the CSI report(s) transmitted in step S405 may include CSI report(s) for the communication link and/or CSI report(s) for the sidelink. The CSI report for the communication link may be a CSI report for the Uu interface between the base station and the transmitting terminal. The CSI report for the sidelink may be a CSI report for the PC5 interface between the transmitting terminal and the receiving terminal. The base station may receive the CSI report(s) from the transmitting terminal. The base station may support communication between the base station and the transmitting terminal and/or sidelink communication between the transmitting terminal and the receiving terminal based on the CSI report(s).

[ SL SPS Periodic feedback method of CSI report used]

When the size of the PSSCH is set in advance, the transmitting terminal may transmit CSI request information to the receiving terminal according to an autonomous determination or a determination of a base station (eg, a serving base station). Here, the CSI request information may request periodic CSI reporting. The receiving terminal may receive CSI request information from the transmitting terminal, and may periodically transmit the CSI report(s) to the transmitting terminal according to the CSI request information. Here, the CSI report(s) may be transmitted from the receiving terminal to the transmitting terminal through the PSFCH. When the SL SPS resource overlaps the CSI resource, the CSI feedback operation may be performed according to a procedure defined in the technical standard. The SL SPS resource may be a resource configured according to the SL SPS, and the CSI resource may be a resource configured for transmission of a CSI report.

In the proposed method, when the priority of the SL-SCH (eg, SL-SCH transmitted through the SL SPS resource) is higher than the priority of CSI reporting, CSI reporting in the overlapped resource between the SL SPS resource and the CSI resource Instead, SL-SCH may be transmitted.

In another proposed method, when an overlapped resource (eg, time resource, slot) between the SL SPS resource and the CSI resource (eg, a resource for periodic CSI reporting) is preset, the SL-SCH and the CSI report are It can be transmitted through the same PSSCH. In this case, the SL-SCH may be rate matched in the PSSCH.

[How to prioritize CSI reporting]

One terminal may perform uplink communication or sidelink communication. In uplink communication or sidelink communication, the CSI report(s) may be transmitted together with other data. In this case, the UE may select one or more CSI reports having a high priority among the CSI report(s), and may map the selected one or more CSI reports to an uplink channel or a sidelink channel.

The base station (eg, serving base station) may set J PUCCH resources to the terminal using higher layer signaling. For example, the base station may set a multi-CSI-PUCCH-Resource-List in the terminal. J may be an integer of 1 or more. For example, the UE may wish to transmit a plurality of CSI reports through a PUCCH in one slot. In this case, the UE may select one PUCCH resource from PUCCH resource #0 to PUCCH resource #J-1. The base station may define (eg, set) PUCCH resource #0 to PUCCH resource #J-1. In this case, it may be defined to increase the size of the PUCCH resource (eg, the number of resource elements (REs) × coding rate × modulation rate). Therefore, the size of PUCCH resource #1 may be larger than the size of PUCCH resource #0.

When the CSI report(s) and other UCI (uplink control information) may be transmitted in PUCCH resource #0, the UE may transmit the CSI report(s) and other UCI using PUCCH resource #0. The CSI report(s) can be encoded along with other UCIs. A cyclic redundancy check (CRC) may be added to the CSI report(s) and other UCIs. Other UCI may include SR (scheduling request) and/or HARQ response. The HARQ response may be referred to as HARQ-ACK, and may include acknowledgment (ACK) or negative ACK (NACK). If UCI different from the CSI report(s) cannot be transmitted in PUCCH resource #0, the UE may use PUCCH resource #1. That is, when UCI different from the CSI report(s) can be transmitted in PUCCH resource #1, the UE may transmit a UCI different from the CSI report(s) using PUCCH resource #1.

When transmission of CSI report(s) and other UCI is impossible in PUCCH resource #0-1, one or more CSI reports among CSI report(s) may not be transmitted. One or more CSI reports excluded from transmission may be determined based on a predefined equation (eg, priority). For example, the priority of each CSI report may be determined based on Equation 1 below.

N _cells may be indicated by signaling (eg, higher layer signaling) and may mean the maximum number of serving cells. M _s may be indicated by signaling (eg, higher layer signaling), and may mean the maximum number for the configuration of CSI reports. y may indicate the CSI reporting method. When the CSI report is an aperiodic CSI report transmitted on the PUSCH, y may be set to 0. When the CSI report is a semi-static CSI report transmitted on the PUSCH, y may be set to 1. When the CSI report is a semi-fixed CSI report transmitted on the PUCCH, y may be set to 2. When the CSI report is a periodic CSI report transmitted on the PUCCH, y may be set to 3.

k may indicate the type of CSI report. When the CSI report includes a reference signal received power (L1-RSRP), k may be set to 0. When the CSI report includes information other than L1-RSRP, k may be set to 1. c may indicate an index of a serving cell. s may indicate a CSI reporting index (eg, CSI index). As pri( y,k,c,s ) is smaller, it may be determined that the corresponding CSI report has a higher priority.

Meanwhile, one or more CSI reports may be configured to be transmitted on the PUSCH. That is, y may be set to 0 or 1. In this case, transmission of the two CSI reports may collide. For example, CSI report #1 may be set to be transmitted on PUSCH, and CSI report #2 may be set to be transmitted on PUSCH. One or more symbols included in the PUSCH configured for CSI report #1 may overlap with one or more symbols included in the PUSCH configured for CSI report #2 in the time domain. In this case, the UE may select a CSI report having a high priority (e.g., small pri ( y,k,c,s )) from CSI report #1 and CSI report #2, and the selected CSI report from PUSCH Can be transmitted.

In another embodiment, CSI report #1 may be set to be transmitted on PUCCH, and CSI report #2 may be set to be transmitted on PUSCH. One or more symbols included in the PUCCH configured for CSI report #1 may overlap with one or more symbols included in the PUSCH configured for CSI report #2 in the time domain. In this case, the UE may not transmit a CSI report having a low priority (eg, large pri( y,k,c,s )) among CSI report #1 and CSI report #2.

In another embodiment, one or more CSI reports may be configured to be transmitted on the PUCCH. That is, y may be set to 2 or 3. For example, CSI report #1 may be set to be transmitted on PUCCH, and CSI report #2 may be set to be transmitted on PUCCH. One or more symbols included in the PUCCH configured for CSI report #1 may overlap with one or more symbols included in the PUCCH configured for CSI report #2 in the time domain. In this case, the UE may not transmit a CSI report having a low priority (eg, large pri( y,k,c,s )) among CSI report #1 and CSI report #2. That is, the UE may select a CSI report having a high priority (eg, small pri ( y,k,c,s )) among CSI report #1 and CSI report #2, and transmit the selected CSI report on the PUCCH. I can. Here, one or more CSI reports may be selected, and the selected CSI report(s) may be multiplexed on the PUCCH. The PUCCH resource through which the selected CSI report(s) is transmitted may be PUCCH resource #J-1.

The CSI report for the Uu interface (eg, a radio link between a base station and a terminal) may be measured in a downlink (DL) bandwidth part (BWP) or a DL carrier. The above-described CSI reporting method (eg, a CSI reporting method for a Uu interface) may be applied for CSI reporting on a PC5 interface (eg, a sidelink between terminals). CSI reporting for the PC5 interface can be measured in SL BWP or SL carrier.

Equation 1 described above (for example, pri( y,k,c,s )) is "when the receiving terminal transmits a CSI report to the transmitting terminal in sidelink communication" and/or "sidelink communication, downlink This may be applied to a case where a transmitting terminal performing communication and/or uplink communication transmits a CSI report to a base station (eg, a serving base station).

[How to determine the priority of CSI reporting in sidelink communication]

The receiving terminal may transmit the CSI report(s) to the transmitting terminal using PSFCH and/or PSSCH. The receiving terminal may determine the priority of CSI reporting by using Equation 1. That is, Equation 1 can be applied to the PC5 interface. However, the meaning of some element(s) in Equation 1 applied to the PC5 interface may be different from the meaning of some element(s) in Equation 1 applied to the Uu interface.

N _cells may be indicated by signaling (eg, higher layer signaling) and may mean the maximum number of serving cells. M _s may be indicated by signaling (eg, higher layer signaling), and may mean the maximum number for CSI configuration. y may indicate the reporting method of CSI. "When a CSI report for sidelink communication is triggered and the corresponding CSI report is transmitted through the PSSCH", y may be set to 0. That is, when the transmission method of the CSI report is the triggering transmission method, y may be set to 0. "When the CSI report for sidelink communication is semi-statically activated and the CSI report is transmitted through the PSSCH", y may be set to 1. "When the CSI report for sidelink communication is semi-statically activated and the CSI report is transmitted through the PSFCH", y may be set to 2. That is, when the transmission method of the CSI report is a semi-persistent transmission method, y may be set to 1 or 2.

When the CSI report for sidelink communication is periodically transmitted through the PSFCH, y may be set to 3. That is, when the transmission method of the CSI report is a periodic transmission method, y may be set to 3. In sidelink communication, periodic CSI reporting may not be defined. In this case, the triggered CSI report may be transmitted through PSSCH or PSFCH. Therefore, the value of y for sidelink communication may not be classified into four values. For example, the value of y for sidelink communication may be divided into two or three values. y may be used to distinguish a channel (eg, PSFCH or PSSCH) through which the triggered CSI report is transmitted. Depending on the CSI reporting scheme, a channel (eg, PSFCH or PSSCH) through which CSI reporting can be transmitted may vary.

k may indicate the type of CSI report. When the CSI report includes L1-RSRP, k may be set to 0. When the CSI report includes information other than L1-RSRP, k may be set to 1. c may indicate a serving cell index. s may indicate a CSI reporting index (eg, CSI index). As pri( y,k,c,s ) is smaller, it may be determined that the corresponding CSI report has a higher priority. The order of important elements for determining the priority of CSI reporting may be "CSI reporting method (y) → CSI type (k) → serving cell index (c) → CSI reporting index (s)". That is, among elements used to determine the priority of CSI reporting, the importance of the CSI reporting method (y) may be the highest and the importance of the CSI reporting index (s) may be the lowest.

Meanwhile, the sidelink resource region may be configured so that the PSSCH does not overlap with the PSFCH in the time domain. In this case, it may not be necessary to determine the priority of CSI reporting. For example, the time resource region in which the PSSCH is transmitted may be set to be always orthogonal to the time resource region in which the PSFCH is transmitted. However, transmission of the CSI report may be multiplexed in one physical channel (eg, PSSCH) instead of two or more physical channels in the same slot. In this case, the priority of CSI reporting corresponding to different physical channels should be determined.

In the proposed method, a physical channel through which the CSI report is transmitted may be considered in order to determine the priority of the CSI report. The physical channel considered for CSI reporting may be two physical channels (eg, PSSCH, PSFCH). A first element indicating a physical channel through which the CSI report is transmitted may be set. The first element set to the first value may indicate that the CSI report is transmitted using the PSSCH. The first element set to the second value may indicate that the CSI report is transmitted using the PSFCH.

"CSI reporting is semi-fixedly activated" may be distinguished from "CSI reporting is triggered". In the proposed method, a CSI reporting scheme may be considered to determine the priority of CSI reporting. For example, the CSI reporting method may be classified into a triggering transmission method and a semi-fixed transmission method. Alternatively, the CSI reporting method may be classified into a triggering transmission method, a semi-fixed transmission method, and a periodic transmission method. The physical channel considered for CSI reporting may be two physical channels (eg, PSSCH, PSFCH). The above-described first element may indicate a CSI reporting method as well as a physical channel through which the CSI report is transmitted.

The first element set to the first value may indicate that the CSI report is transmitted using the PSSCH. The first element set to the second value may indicate that the CSI report is transmitted using the PSFCH. The first element set to the third value may indicate that the triggered CSI report is transmitted using the PSSCH. That is, the first element set to the third value may indicate that the triggering transmission method is used. The first element set to the fourth value may indicate that the semi-statically activated CSI report is transmitted through the PSSCH. That is, the first element set to the fourth value may indicate that the semi-fixed transmission method is used. In this case, the CSI reporting method through the PSSCH can be classified into three types.

Meanwhile, the sidelink communication (eg, PC5 interface) may support a unicast method, a multicast method, a groupcast method, and/or a broadcast method. Different priorities may be assigned to each cast method for CSI reporting. In order to support this operation, the cast method may be reflected in a function that determines the priority of CSI reporting.

In the proposed method, a CSI report cast method may be considered in order to determine the priority of the CSI report. In order to support this operation, when setting a CSI report index (eg, a CSI index), the CSI report index may be sorted according to a cast method. For example, in Equation 1, s may refer to the CSI reporting index. The CSI report index (s) may be allocated according to the priority of the cast method (eg, unicast method, multicast method, groupcast method, broadcast method), and based on the corresponding CSI report index (s) The priority of CSI reporting can be determined.

However, additional signaling may be required to allocate new CSI reporting index(s) for sidelink communication. The reason is that when a new CSI report index(s) is allocated, the existing CSI report index(s) must be rearranged, and the CSI report index(s) must be reset to support this operation. A method that requires less signaling than that required for a method of determining the priority of CSI reporting using the CSI reporting index may be required.

In the proposed method, in order to determine the priority of the CSI report, a new element(s) indicating the cast method of the CSI report may be introduced. The priority of the CSI report may be determined according to a function, and different priorities may be assigned for each cast method of the CSI report. CSI reporting according to the cast method may be performed in one serving cell. For example, the UE may determine the priority of CSI reporting based on Equation 2 below.

N _cells may be indicated by signaling (eg, higher layer signaling) and may mean the maximum number of serving cells. M _s may be indicated by signaling (eg, higher layer signaling), and may mean the maximum number for the configuration of CSI reports. y may indicate the CSI reporting method. k may indicate the type of CSI report. s may indicate a CSI reporting index (eg, CSI index).

In order to determine the CSI reporting index (s) defined in the same serving cell, one or more step(s) may be added. The maximum number of CSI reports according to each cast method may be defined. For example, M _sB may indicate the maximum number of CSI reports transmitted according to a broadcast scheme. M _sG may indicate the maximum number of CSI reports transmitted according to the _groupcast method. M _sU may indicate the maximum number of CSI reports transmitted according to the unicast scheme. Priorities may be assigned for each cast method (r). Here, the value of “M _sB + M _sG + M _sU ” may not be greater than M _s . The CSI reporting index (s) may be extended to (r,s).

For example, when r (eg, r=0) set as the first value indicates the broadcast method, (r,s) may be interpreted as s. When r (eg, r=1) set as the second value indicates the groupcast method, (r,s) may be interpreted as “s+M _sB ”. When r (eg, r=2) set as the third value indicates the unicast method, (r,s) may be interpreted as “s+M _sB +M _sG ”.

For another example, when r (eg, r=0) set as the first value indicates the groupcast method, (r,s) may be interpreted as s. When r (eg, r=1) set as the second value indicates the unicast method, (r,s) may be interpreted as “s+M _sG ”. Here, the values of r (eg, a first value, a second value, and a third value) may be set regardless of the size. The priority of the CSI report may be calculated according to a function that determines the priority.

[How to determine the priority of CSI reporting in sidelink/downlink/uplink communication]

In order to determine the priority of CSI reporting, the priority between sidelink communication, downlink communication, and uplink communication may be determined according to an interface (eg, a PC5 interface, a Uu interface). Alternatively, the priority between sidelink communication, downlink communication, and uplink communication may be determined in consideration of an interface (eg, a PC5 interface, a Uu interface) and other factor(s).

In the proposed method, the priority of CSI reporting may be determined according to an interface (eg, PC5 interface, Uu interface). For example, the priority of CSI reporting for the PC5 interface (e.g., CSI reporting for sidelink) is the priority of CSI reporting for the Uu interface (e.g., CSI reporting for downlink or uplink). And can be set differently.

The terminal (eg, the transmitting terminal) can manage the PC5 interface and the Uu interface. Therefore, it may be desirable to set the priority of the PC5 interface different from that of the Uu interface. In order to simplify the operation of the terminal (eg, the transmitting terminal), the priority of all CSI reports belonging to one interface may be higher than the priority of all CSI reports belonging to another interface.

When the terminal (eg, the transmitting terminal) operates according to mode 1, the link (eg, downlink, uplink) between the transmitting terminal and the base station (eg, serving base station) is It may be more important than a link (eg, a sidelink). Alternatively, a link (eg, sidelink) between a transmitting terminal and a receiving terminal may be more important than a link (eg, downlink, uplink) between a transmitting terminal and a base station (eg, a serving base station). In this case, emergency data and/or important data may be transmitted and received through a sidelink. The priority between links (eg, interfaces) can be considered to determine the priority of CSI reporting.

In the proposed method, a new element (z) indicating an interface (eg, PC5 interface, Uu interface) related to CSI reporting is introduced into a function (eg, Equation 2) to determine the priority of CSI reporting. Can be. For example, z set to the first value (eg, z=0) may indicate the Uu interface. Z (eg, z=1) set as the second value may indicate the PC5 interface. In Equation 2 (pri _{proposed ( z,y,k,c,s )} ), the maximum value of y may be 3. The terminal (eg, the transmitting terminal) may appropriately determine the priority of the CSI report by changing the value of z in Equation 2.

In the proposed method, the priority of CSI reporting may be determined regardless of an interface (eg, PC5 interface, Uu interface). In this case, since the priority of the CSI report is determined regardless of the type of the interface, a function defined in the technical standard may be used to determine the priority of the CSI report. "When the terminal (eg, the transmitting terminal) simultaneously supports the Uu interface and the PC5 interface, and the SL BWP and the UL BWP are set (eg, activated) on the same carrier", the serving cell index (c) is appropriately May not be defined. The reason is that in a communication system supporting frequency division duplexing (FDD), the serving cell index c of the DL BWP (eg, DL carrier) is the serving cell index c of the UL BWP (eg, UL carrier). Because it is the same as ).

Therefore, the priority of the CSI report derived by the transmitting terminal based on the CSI-RS received from the DL BWP (eg, the DL carrier) is the CSI-RS received by the receiving terminal from the SL BWP (eg, the SL carrier). It may not be distinguished from the priority of the CSI report derived based on. The CSI report derived from the receiving terminal may be reported to the transmitting terminal, and the transmitting terminal may not be able to distinguish between the priority of the CSI report for the DL BWP and the priority of the CSI report for the SL BWP. Here, the SL BWP may be set in the same carrier as the UL BWP associated with the DL BWP. To solve this problem, the index of the SL BWP (eg, SL carrier) may be set differently from the index of each of the DL BWP (eg, DL carrier) and UL BWP (eg, UL carrier). .

In the proposed method, the serving cell index for “DL BWP (eg, DL carrier)” or “UL BWP (eg, UL carrier)” is a serving cell for SL BWP (eg, SL carrier). It can be set differently from the index. In this case, the terminal (eg, the transmitting terminal) has the index of the SL BWP (eg, the SL carrier) associated with the CSI report for the sidelink communication "DL BWP associated with the CSI report for the downlink communication (eg For example, it can be seen that the index of the DL carrier" or "the index of the UL BWP (eg, UL carrier) associated with CSI reporting for uplink communication" is distinguished. To support this operation, a base station (e.g., a serving base station) is a SL BWP (e.g., an SL carrier), a DL BWP (e.g., a DL carrier), and a UL BWP (e.g., a UL carrier). You can determine the priority of the liver. The determined priority may be signaled from the base station to a terminal (eg, a transmitting terminal, a receiving terminal).

[Method of simultaneous transmission of HARQ response (eg, HARQ-ACK) and CSI]

Transmission of the HARQ response (eg, HARQ-ACK bit) and the CSI report in the same channel (eg, the same slot) may be configured in the terminal (eg, the receiving terminal). The setting of this operation may be signaled by the base station and/or the transmitting terminal. When the HARQ response and the CSI report are transmitted in the same slot, the physical channel through which the HARQ response is transmitted in the same slot may be different from the physical channel through which the CSI report is transmitted. The physical channel through which the HARQ response is transmitted in the same slot may be multiplexed with the physical channel through which the CSI report is transmitted in the time domain or frequency domain. Whether to transmit the HARQ response and the CSI report in the same channel or in the same slot may be determined according to the processing capability of the terminal (eg, the receiving terminal). Here, the processing capability of the terminal includes processing capability for decoding the DL-SCH or SL-SCH to derive the HARQ response(s) and/or the processing capability for estimating the channel to derive the CSI report(s). can do. The above-described operation(s) may not be allowed in the transmitting terminal.

When the Uu interface or the PC5 interface is supported, whether to transmit the HARQ response and the CSI report in the same slot (or the same channel) may be determined according to the above-described processing capability. If both the PC5 interface and the Uu interface are supported, the first terminal (eg, the transmitting terminal) is the HARQ response(s) and/or the CSI report(s) received from the second terminal (eg, the receiving terminal) Can be delivered to another communication node (eg, a base station). In this case, the first terminal may perform a repeater function. HARQ response(s) and CSI report(s) transmitted from the first terminal to other communication nodes are not only HARQ response(s) and CSI report(s) of the first terminal, but also HARQ response(s) of the second terminal and/ Or CSI report(s).

For example, among the HARQ response(s) that the transmitting terminal transmits to the base station (eg, serving base station), some HARQ response(s) may be the result of decoding the SL-SCH in the receiving terminal, and the remaining HARQ response (S) may be a result of decoding the DL-SCH by the transmitting terminal. Among the CSI report(s) transmitted by the transmitting terminal to the base station (eg, serving base station), some CSI report(s) may be the result of estimating CSI-RS for sidelink communication by the receiving terminal, and the remaining CSI The report(s) may be a result of estimating CSI-RS for downlink communication and/or uplink communication by the transmitting terminal. The UCI of the transmitting terminal (eg, HARQ response, CSI report) may be distinguished from the SL feedback information (eg, HARQ response, CSI report) received from the receiving terminal. Processing capacity additionally required for the transmitting terminal for relaying SL feedback information may not be large.

In the proposed method, the base station can configure the UE (eg, the transmitting terminal and the receiving terminal) to perform simultaneous transmission of the HARQ response and the CSI report using higher layer signaling. A parameter indicating the simultaneous transmission of the HARQ response and the CSI report may be included in the RRC message. "Parameter instructing to perform simultaneous transmission of HARQ response and CSI report" included in the RRC message for the Uu interface is a parameter indicative of performing simultaneous transmission of "HARQ response and CSI report" included in the RRC message for PC5 interface It may be different from ".

[Method of transmitting CSI report and/or HARQ response through PSFCH]

In sidelink communication, each transmission of the HARQ response and CSI report may be activated or deactivated. In the following embodiments, a case in which both transmission of a HARQ response and a CSI report for sidelink communication are activated may be considered.

The receiving terminal can receive the SL-SCH (for example, sidelink data) from the transmitting terminal, can perform a decoding operation on the SL-SCH, and a HARA response (for example, according to the result of the decoding operation) ACK or NACK) can be generated. The receiving terminal may transmit the HARQ response to the transmitting terminal using the PSFCH. The PSFCH used for transmission of the HARQ response may be indicated by SCI or preset feedback timing. SCI (eg, 1 ^st -stage SCI and/or 2 ^nd -stage SCI) associated with scheduling information (eg, resource allocation information) of SL-SCH may include CSI request information.

The SCI may include time resource information (eg, slot index, slot offset) of the PSSCH (or PSFCH) through which the CSI report is transmitted. Alternatively, the SCI may not include time resource information of the PSSCH (or PSFCH) through which the CSI report is transmitted. That is, the time resource information of the PSSCH (or PSFCH) through which the CSI report is transmitted may be explicitly or implicitly indicated to the terminal (eg, the receiving terminal).

The HARQ response (eg, HARQ-ACK bit) for the SL-SCH may be transmitted through the PSFCH. The SCI may include time resource information (eg, slot index, slot offset) of the PSFCH through which the HARQ response is transmitted. Alternatively, the SCI may not include time resource information of the PSFCH through which the HARQ response is transmitted. That is, the time resource information of the PSFCH on which the HARQ response is transmitted may be explicitly or implicitly indicated to the terminal (eg, the receiving terminal).

When the SCI indicates the time resource used for the transmission of the CSI report in the transmission procedure of the CSI report for the sidelink communication, the time resource for the CSI report indicated by the SCI is the time resource of the PSFCH in which the HARQ response is transmitted and They can be the same or different. Resources for transmission of HARQ responses and/or CSI reports in sidelink communication may be explicitly or implicitly indicated. Alternatively, resources for transmission of HARQ responses and/or CSI reports in sidelink communication may be defined in the technical standard. The HARQ response and CSI report for sidelink communication may be fed back to the transmitting terminal through the same physical channel. Alternatively, the HARQ response and CSI report for sidelink communication may be fed back to the transmitting terminal through different time resources. Here, different time resources may belong to the same physical channel or different physical channels.

Meanwhile, the transmitting terminal may transmit information indicating the existence of the periodically transmitted CSI-RS to the receiving terminal. This information may be transmitted by one or a combination of two or more of higher layer signaling, MAC signaling, and PHY signaling (eg, SCI). The receiving terminal may receive a periodic CSI-RS from the transmitting terminal, and may generate CSI report(s) based on the periodic CSI-RS. The receiving terminal may transmit the CSI report(s) to the transmitting terminal using the PSSCH and/or PSFCH. The resources (eg, PSSCH, PSFCH) used for transmission of the CSI report may be indicated when a request for the CSI report is set. For example, SCI may include information indicating a resource used for transmission of a CSI report as well as CSI request information. Alternatively, the CSI report(s) may be multiplexed on different physical channels transmitted by the receiving terminal to the transmitting terminal. The multiplexing method of the CSI report(s) may be predefined in the technical standard.

For example, the receiving terminal may periodically transmit the PSSCH to the transmitting terminal. When a periodic CSI report is indicated, and the period (eg, period and slot offset) of the PSSCH coincides with the period (eg, period and slot offset) of the CSI report, the receiving terminal performs the CSI report and SL- The SCH can be multiplexed, and the multiplexed CSI report and SL-SCH can be transmitted through the PSSCH. For another example, when there is no other physical channel transmitted from the receiving terminal to the transmitting terminal, the receiving terminal may transmit only the CSI report. In this case, the receiving terminal may transmit a CSI report to the transmitting terminal using the PSFCH.

The PSFCH through which the CSI report is transmitted may be composed of one or more symbols in the time domain. For example, in the time domain, the PSFCH may consist of 1 or 2 symbols. The PSFCH may be a physical channel to which "coded CSI report" or "coded CSI report and HARQ response" is mapped. For example, PUCCH format 2 may be used.

In the proposed method, the CSI report may be transmitted on the PSFCH alone. The transmitting terminal may request transmission of the CSI report to the receiving terminal and may transmit a CSI-RS. The receiving terminal may receive the CSI-RS from the transmitting terminal, and may derive the CSI report(s) based on the received CSI-RS. The CSI-RS may be a periodic or aperiodic CSI-RS. When the CSI report is triggered, the transmitting terminal may transmit information indicating that the CSI-RS is transmitted together with the CSI request information to the receiving terminal. In this case, the resource used for transmission of the CSI report in the receiving terminal may be allocated or reserved by the transmitting terminal.

The resource available in the receiving terminal may be a PSSCH. For example, a resource used for transmission of a CSI report in a receiving terminal may be a PSSCH. When a specific mode of sidelink communication (eg, a fourth sub-mode of the second mode in the NR communication system) is used, the transmitting terminal may allocate the sidelink resource(s) to the receiving terminal. For example, the sidelink resource(s) may be autonomously allocated by the transmitting terminal. When a mode other than a specific mode is used in the sidelink communication, the transmitting terminal may not be able to allocate the sidelink resource(s) to the receiving terminal.

The receiving terminal may transmit the CSI report(s) to the transmitting terminal using a resource set (in advance) for the receiving terminal or a resource indicated by the base station. When this operation is used, there may be a time delay for CSI reporting. Therefore, this operation may not be suitable in an environment where the fading of the radio channel is frequently changed.

The resource available in the receiving terminal may be PSFCH. For example, the resource used for transmission of the CSI report in the receiving terminal may be PSFCH. The transmitting terminal may transmit information indicating the PSFCH resource (eg, resource index) to the receiving terminal. Information indicating the PSFCH resource (eg, resource index) may be indicated to the receiving terminal through an implicit method, an explicit method, or a combination of an implicit method and an explicit method. PSFCH can be supported in all modes for sidelink communication. The method of indicating PSFCH resources may be simpler than the method of indicating PSSCH resources. Accordingly, the size of control information required to indicate the PSFCH resource may be smaller than the size of control information required to indicate the PSSCH resource.

In addition, the size of the CSI report for sidelink communication may be known in advance to the transmitting terminal and the receiving terminal. Depending on the type of PMI codebook to be derived by the receiving terminal, the size of the PMI (eg, the number of bits constituting the PMI) may be different. In addition, the size of the PMI and/or the size of the CQI may be affected by the size of the RI. Therefore, there may be cases where the exact size of the CSI report cannot be known in the NR communication system. In particular, when the CSI report is transmitted through the PUCCH, the base station (eg, the serving base station) may perform a blind decoding operation to obtain the CSI report. However, since the number of CSI-RS antenna ports used in sidelink communication is small, the size of the CSI report may not vary greatly depending on the size of the PMI.

The transmitting terminal may transmit CSI request information to the receiving terminal, and the CSI report may be transmitted through the PSFCH. The physical channel used for transmission of the CSI report may not be limited to the PSFCH. For example, the receiving terminal may transmit CSI report(s) to the transmitting terminal using PSSCH and/or PSFCH. This operation can be set by the transmitting terminal.

In the proposed method, the physical channel (eg, PSSCH and/or PSFCH) through which the CSI report is transmitted may be determined according to the SCI format. The transmitting terminal may transmit the SCI including scheduling information (eg, resource allocation information) of the SL-SCH to the receiving terminal. Here, the SCI may be used to schedule the SL-SCH transmitted from the transmitting terminal to the receiving terminal. This SCI may be referred to as “SCI Format A”. Alternatively, the SCI may be used to schedule the SL-SCH transmitted from the receiving terminal to the transmitting terminal. This SCI may be referred to as “SCI Format B”. That is, the aforementioned SCIs may have different formats. SCI format A (eg, 1 ^st -stage SCI and/or 2 ^nd -stage SCI of SCI format A) may include CSI request information. Alternatively, SCI format B (eg, 1 ^st -stage SCI and/or 2 ^nd -stage SCI of SCI format B) may include CSI request information.

In the proposed method, the CSI report may be concatenated with the HARQ response, and the concatenated CSI report and the HARQ response may be transmitted through PSFCH. SCI (eg, SCI format A and/or SCI format B) may include information indicating that the CSI report is transmitted on the PSFCH. SCI format A may instruct the receiving terminal to perform not only the transmission operation of the CSI report but also the SL-SCH reception operation. In this case, the receiving terminal may transmit a HARQ response (eg, HARQ-ACK bit) that is a result of decoding of the SL-SCH on the PSFCH, and may transmit the CSI report(s) on the PSFCH. The PSFCH through which the HARQ response is transmitted may be the same as the PSFCH through which the CSI report(s) is transmitted. Alternatively, the PSFCH through which the HARQ response is transmitted may be different from the PSFCH through which the CSI report(s) is transmitted.

It may be configured that the receiving terminal transmits the HARQ response and the CSI report on the same PSFCH. Alternatively, in the technical standard, it may be defined that the receiving terminal transmits the HARQ response and the CSI report on the same PSFCH. In this case, the receiving terminal may simultaneously transmit the HARQ response and the CSI report on the same PSFCH.

Alternatively, it may be configured that the receiving terminal does not simultaneously transmit the HARQ response and the CSI report. For example, if the processing power of the receiving terminal is insufficient, the receiving terminal may not be able to complete the operation of generating the HARQ response and the operation of generating the CSI report in the same time interval (eg, slot or mini-slot). In this case, the receiving terminal may transmit the HARQ response and CSI report(s) on different PSFCHs. To support this operation, the SCI may include information indicating the PSFCH for transmission of the HARQ response and information indicating the PSFCH for transmission of the CSI report.

In order to reduce the size of the SCI (eg, the number of bits constituting the SCI), it may be desirable to derive another PSFCH resource from one PSFCH resource. For example, the SCI may include a time offset (eg, slot offset, mini slot offset, symbol offset) between a specific PSFCH and another PSFCH. A specific PSFCH may be directly indicated by resource allocation information included in the SCI, and another PSFCH may be indicated by resource allocation information and a time offset of a specific PSFCH. That is, the receiving terminal may check a specific PSFCH (eg, PSFCH for transmission of a HARQ response and/or CSI report) based on the resource allocation information included in the SCI received from the transmitting terminal, and the specific PSFCH and SCI Other PSFCHs can be identified using the included time offset.

When the HARQ response and the CSI report are transmitted on the same PSFCH, a channel coding operation for the HARQ response and the CSI report may be performed, and the encoded HARQ response and the CSI report may be mapped to the PSFCH.

The channel coding operation applied to the HARQ response may be different from the channel coding operation applied to the CSI report. This is because the error rate required for the HARQ response may be different from the error rate required for CSI reporting. The terminal (eg, the receiving terminal) can generate one codeword by performing a channel encoding operation for the HARQ response, and generating one codeword by performing a channel encoding operation for the CSI report. I can. The codeword for the HARQ response may be different from the codeword for the CSI report. The codeword for the HARQ response may be concatenated with the codeword for the CSI report, and the concatenated codewords may be mapped to the PSFCH. The code rate applied to each of the HARQ response and CSI report may be preset. Alternatively, the SCI may include information (eg, index) indicating a code rate applied to each of the HARQ response and the CSI report. The receiving terminal may check a code rate applied to each of the HARQ response and CSI report based on information included in the SCI received from the transmitting terminal.

The channel coding operation applied to the HARQ response may be the same as the channel coding operation applied to the CSI report. The HARQ response and the CSI report may be transmitted on the same PSFCH. The terminal (eg, the receiving terminal) may concatenate the HARQ response and the CSI report, and may generate one codeword by performing the same channel coding operation for the concatenated HARQ response and CSI report. One codeword can be mapped to the PSFCH. The channel encoding operation may be performed using a Reed Muller code or a polar code. The code rate applied to the PSFCH may be preset. Alternatively, the SCI may include information (eg, an index) indicating a code rate applied to the PSFCH. The receiving terminal can check the code rate applied to the PSFCH based on the information included in the SCI received from the transmitting terminal.

The methods according to the present invention may be implemented in the form of program instructions that can be executed through various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like alone or in combination. The program instructions recorded on the computer-readable medium may be specially designed and configured for the present invention, or may be known and usable to those skilled in computer software.

Examples of computer-readable media include hardware devices specially configured to store and execute program instructions, such as rom, ram, flash memory, and the like. Examples of program instructions include not only machine language codes such as those produced by a compiler, but also high-level language codes that can be executed by a computer using an interpreter or the like. The above-described hardware device may be configured to operate as at least one software module to perform the operation of the present invention, and vice versa.

Although described with reference to the above embodiments, those skilled in the art will understand that various modifications and changes can be made to the present invention without departing from the spirit and scope of the present invention described in the following claims. I will be able to.

Claims (20)

As a method of operating a first terminal in a communication system,
Transmitting CSI request information for requesting transmission of a channel state information (CSI) report to a second terminal;
Receiving a CSI report #1 for a sidelink between the first terminal and the second terminal from the second terminal in a sidelink channel; And
And transmitting one or more CSI reports from among the CSI report #1 and CSI report #2 for a communication link between the first terminal and the base station to the base station in an uplink channel. The method according to claim 1,
The priority of the CSI report #1 is determined according to the type of the sidelink channel through which the CSI report #1 is transmitted, and the sidelink channel is a physical sidelink feedback channel (PSFCH) or a physical sidelink shared channel (PSSCH), Operation method of the first terminal. The method according to claim 1,
The priority of the CSI report #1 is determined according to the transmission method of the CSI report #1, and the transmission method is a triggering transmission method, a semi-persistent transmission method, or a periodic transmission method. Phosphorus, the operation method of the first terminal. The method according to claim 1,
The priority of the CSI report #1 is determined according to a sidelink communication method between the first terminal and the second terminal, and the sidelink communication method is a unicast method, a groupcast method, or a broadcast method. A method of operating a first terminal, which is a broadcast method. The method according to claim 1,
The one or more CSI reports are selected according to the priority of the CSI report #1 and the priority of the CSI report #2, and the uplink channel is a physical uplink control channel (PUCCH) or a physical uplink shared channel (PUSCH), Operation method of the first terminal. The method according to claim 1,
The priority of the sidelink is set differently from the priority of the communication link, the priority of the CSI report #1 is determined in consideration of the priority of the sidelink, and the priority of the CSI report #2 is the communication The operation method of the first terminal is determined in consideration of the priority of the link. The method according to claim 1,
When the cell index associated with the sidelink is the same as the cell index associated with the communication link, the priority of the CSI report #1 and the priority of the CSI report #2 are independent of the priority between the sidelink and the communication link. Determined, the operation method of the first terminal. The method according to claim 1,
The operating method of the first terminal,
Further comprising the step of transmitting data to the second terminal,
Hybrid automatic repeat request (HARQ) response to the data and the CSI report #1 are received on the same sidelink channel, the operating method of the first terminal. The method of claim 8,
The CSI request information and scheduling information for the data are included in sidelink control information (SCI) transmitted from the first terminal to the second terminal. As a method of operating a second terminal in a communication system,
Receiving a channel state information-reference signal (CSI-RS) from the first terminal in a sidelink between the first terminal and the second terminal;
Generating a plurality of CSI reports based on the CSI-RS;
Selecting one or more CSI reports according to priority from among the plurality of CSI reports; And
And transmitting the one or more CSI reports to the first terminal in a sidelink channel. The method of claim 10,
The priorities of the plurality of CSI reports are determined according to the type of the sidelink channel through which each CSI report is transmitted, and the sidelink channel is a physical sidelink feedback channel (PSFCH) or a physical sidelink shared channel (PSSCH). Terminal operation method. The method of claim 10,
Priorities of the plurality of CSI reports are determined according to the transmission method of each CSI report, and the transmission method is a triggering transmission method, a semi-persistent transmission method, or a periodic transmission method, Method of operation of the second terminal. The method of claim 10,
Priorities of the plurality of CSI reports are determined according to a sidelink communication method between the first terminal and the second terminal, and the sidelink communication method is a unicast method, a groupcast method, or a broadcast method. The operation method of the second terminal, which is a broadcast method. The method of claim 10,
The operation method of the second terminal,
Receiving sidelink control information (SCI) including scheduling information for data from the first terminal; And
Further comprising the step of receiving the data from the first terminal based on the scheduling information,
A hybrid automatic repeat request (HARQ) response for the data and the one or more CSI reports are transmitted on the same sidelink channel. As a first terminal in a communication system,
Processor;
A memory in electronic communication with the processor; And
Contains instructions stored in the memory,
When the instructions are executed by the processor, the instructions are performed by the first terminal,
Transmitting a channel state information-reference signal (CSI-RS) in a sidelink between the first terminal and the second terminal;
Receiving CSI report #1 for the CSI-RS from the second terminal in a sidelink channel; And
The CSI report #1 and the CSI report #2 for a communication link between the first terminal and the base station, operating to cause the transmission of one or more CSI reports to the base station in an uplink channel, the first terminal. The method of claim 15,
The priority of the CSI report #1 is determined according to the type of the sidelink channel through which the CSI report #1 is transmitted, and the sidelink channel is a physical sidelink feedback channel (PSFCH) or a physical sidelink shared channel (PSSCH), The first terminal. The method of claim 15,
The priority of the CSI report #1 is determined according to the transmission method of the CSI report #1, and the transmission method is a triggering transmission method, a semi-persistent transmission method, or a periodic transmission method. Phosphorus, the first terminal. The method of claim 15,
The priority of the CSI report #1 is determined according to a sidelink communication method between the first terminal and the second terminal, and the sidelink communication method is a unicast method, a groupcast method, or a broadcast method. The first terminal, which is a broadcast method. The method of claim 15,
The one or more CSI reports are selected according to the priority of the CSI report #1 and the priority of the CSI report #2, and the uplink channel is a physical uplink control channel (PUCCH) or a physical uplink shared channel (PUSCH), The first terminal. The method of claim 15,
The priority of the sidelink is set differently from the priority of the communication link, the priority of the CSI report #1 is determined in consideration of the priority of the sidelink, and the priority of the CSI report #2 is the communication Determined in consideration of the priority of the link, the first terminal.

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