CN113366902A

CN113366902A - Method and apparatus for sidelink multicast communication

Info

Publication number: CN113366902A
Application number: CN202080011824.2A
Authority: CN
Inventors: 崔寿汉; 韩镇百
Original assignee: Hyundai Motor Co; Kia Corp
Current assignee: Hyundai Motor Co; Kia Corp
Priority date: 2019-02-01
Filing date: 2020-01-29
Publication date: 2021-09-07
Also published as: KR20200096413A

Abstract

A method and apparatus for sidelink multicast communication is disclosed. A method of operating a transmitting terminal, comprising the steps of: transmitting SS/PBCH blocks for sidelink communications in respective directions using a beam scanning method; receiving first feedback information on SS/PBCH blocks from a plurality of receiving terminals; and transmits the sidelink channel in a specific direction using the beam of the transmitting terminal determined based on the first feedback information. Accordingly, the communication system performance can be improved.

Description

Method and apparatus for sidelink multicast communication

Technical Field

The present invention relates generally to sidelink communication techniques, and more particularly, to techniques for beamforming-based sidelink communication to support multicast services.

Background

A fifth generation (5G) communication system (e.g., a New Radio (NR) communication system) using a higher frequency band than that of a fourth generation (4G) communication system (e.g., a Long Term Evolution (LTE) communication system or an LTE-advanced (LTE-a) communication system) and a frequency band of the 4G communication system have been considered for processing wireless data. The 5G communication system may support enhanced mobile broadband (eMBB) communication, ultra-reliable and low latency communication (URLLC), large-scale machine type communication (mtc), and so on.

The 4G communication system and the 5G communication system may support vehicle-to-anything (V2X) communication. V2X communications supported in cellular communication systems, such as 4G communication systems, 5G communication systems, and the like, may be referred to as "cellular-V2X (C-V2X) communications. V2X communications (e.g., C-V2X communications) may include vehicle-to-vehicle (V2V) communications, vehicle-to-infrastructure (V2I) communications, vehicle-to-pedestrian (V2P) communications, vehicle-to-network (V2N) communications, and so forth.

In a cellular communication system, V2X communications (e.g., C-V2X communications) may be performed based on a "sidelink" communication technology (e.g., a proximity services (ProSe) -based communication technology, a device-to-device (D2D) communication technology, etc.). For example, a sidelink channel of a vehicle participating in the V2V communication may be established, and the communication between the vehicles may be performed using the sidelink channel.

Meanwhile, sidelink communications may be performed using a high frequency band (e.g., millimeter wave band). In this case, the sidelink communication may be performed in the beam scanning scheme. Accordingly, the transmitting terminal can transmit the sidelink signals and/or channels in all directions by rotating the beam. The sidelink communication may support broadcast services, multicast services, and unicast services.

When the side link communication supports the multicast service, the location of the receiving terminal participating in the multicast service may be limited to a specific area. Even in this case, if the transmitting terminal transmits the sidelink signals and/or channels in all directions according to the beam scanning scheme, a transmission delay may occur due to an unnecessary transmission procedure (e.g., beam transmission to an area where the receiving terminal does not exist), and power loss may increase. Furthermore, unnecessary transmission procedures may cause interference to other communication nodes.

Disclosure of Invention

Accordingly, exemplary embodiments of the present invention provide a method and apparatus for beamforming-based sidelink communication to support a multicast service.

According to an exemplary embodiment of the present invention, an operating method of a transmitting terminal in a communication system may include transmitting a synchronization signal/physical broadcast channel (SS/PBCH) block for sidelink communication in an omni-direction by using a beam scanning scheme; receiving first feedback information of an SS/PBCH block from a plurality of receiving terminals; and transmitting the sidelink channel in a specific direction using a beam of the transmission terminal determined based on the first feedback information, wherein a transmission region corresponding to the specific direction is narrower than a transmission region corresponding to the omni-direction.

The SS/PBCH block may be transmitted within a beam scanning interval configured by a base station to which the transmitting terminal is connected, and the beam scanning interval may be configured within a bandwidth part (BWP) for sidelink communication.

The first feedback information may include a beam index of the transmitting terminal selected based on beam quality measured according to the SS/PBCH block. A transmission interval may be configured based on the first feedback information, and the sidelink channels may be transmitted to the plurality of receiving terminals in a beam scanning scheme within the transmission interval.

The method of operation may further include classifying the plurality of receiving terminals into one or more groups based on the locations of the plurality of receiving terminals identified based on the first feedback information, wherein for each of the one or more groups, the sidelink channels are transmitted in a beam scanning scheme within a transmission interval.

The operating method may further include transmitting configuration information of a transmission interval to the plurality of receiving terminals before transmitting the sidelink channel, wherein the configuration information of the transmission interval includes information indicating a start of the transmission interval, information indicating a length of the transmission interval, information indicating a bandwidth of the transmission interval, information indicating a period of the transmission interval, and an identifier of one or more of the plurality of receiving terminals that perform sidelink communication within the transmission interval.

The method of operation may further include receiving second feedback information regarding the sidelink channel from the plurality of receiving terminals; and determining whether to perform a beam update operation based on second feedback information, wherein the second feedback information includes one or more of a hybrid automatic repeat request (HARQ) response and quality information of sidelink channels.

The side link channel may include a physical side link control channel (PSCCH) and a physical side link shared channel (PSCCH), and the PSCCH may include scheduling information of the PSCCH and trigger information of a beam update operation.

Further, according to an exemplary embodiment of the present invention, an operating method of a receiving terminal in a communication system may include receiving a synchronization signal/physical broadcast channel (SS/PBCH) block for sidelink communication from a transmitting terminal at a beam scanning interval; selecting a beam index of a transmitting terminal based on quality information measured according to the SS/PBCH block; transmitting first feedback information including a beam index to a transmitting terminal; and receiving a sidelink channel from the transmitting terminal in a transmission interval configured based on the first feedback information, wherein the SS/PBCH block is transmitted in an omni-direction of the transmitting terminal in the beam scanning interval, the sidelink channel is transmitted in a specific direction of the transmitting terminal in the transmission interval, and a transmission region corresponding to the specific direction is narrower than a transmission region corresponding to the omni-direction.

The SS/PBCH block may be received within a beam scanning interval configured by a base station to which the receiving terminal is connected, and the beam scanning interval may be configured within a bandwidth part (BWP) for sidelink communication. A transmission interval may be configured for a plurality of receiving terminals including a receiving terminal, and a sidelink channel for each of the plurality of receiving terminals may be transmitted in a beam scanning scheme within the transmission interval.

The operation method may further include receiving configuration information of a transmission interval from the transmitting terminal before the reception-side link channel, wherein the configuration information of the transmission interval includes information indicating a start point of the transmission interval, information indicating a length of the transmission interval, information indicating a bandwidth of the transmission interval, and information indicating a period of the transmission interval.

The method of operation may further include transmitting second feedback information of the sidelink channel to the transmitting terminal, wherein the second feedback information includes one or more of a hybrid automatic repeat request (HARQ) response and quality information of the sidelink channel, and the transmitting terminal determining whether to perform a beam update operation based on the second feedback information. The side link channel may include a physical side link control channel (PSCCH) and a physical side link shared channel (PSCCH), and the PSCCH may include scheduling information of the PSCCH and trigger information of a beam update operation.

Further, according to an exemplary embodiment of the present invention, a transmitting terminal performing a side link communication may include a processor; and a memory storing at least one instruction executable by the processor, wherein the at least one instruction, when executed by the processor, causes the processor to transmit a sidelink signal for beam measurement in an omni-direction by using a beam scanning scheme; receiving first feedback information of a side link signal from a plurality of receiving terminals; the sidelink channel is transmitted in a specific direction using a beam of the transmission terminal determined based on the first feedback information, wherein a transmission region corresponding to the specific direction is narrower than a transmission region corresponding to the omni-direction.

The sidelink signal may be transmitted within a beam sweep interval configured by a base station to which the transmitting terminal is connected, and the beam sweep interval may be configured within a bandwidth part (BWP) for sidelink communication. A transmission interval may be configured based on the first feedback information, and the sidelink channels may be transmitted to the plurality of receiving terminals in a beam scanning scheme within the transmission interval.

The at least one instruction may also cause the processor to classify the plurality of receiving terminals into one or more groups based on locations of the plurality of receiving terminals identified based on the first feedback information, wherein for each of the one or more groups, the sidelink channels are transmitted in a beam scanning scheme within a transmission interval.

The at least one instruction may further cause the processor to transmit, to the plurality of receiving terminals, configuration information of a transmission interval before transmitting the sidelink channel, wherein the configuration information of the transmission interval includes information indicating a start of the transmission interval, information indicating a length of the transmission interval, information indicating a bandwidth of the transmission interval, information indicating a period of the transmission interval, and an identifier of one or more of the plurality of receiving terminals that perform sidelink communication within the transmission interval.

The at least one instruction may further cause the processor to receive second feedback information regarding the sidelink channel from a plurality of receiving terminals; and determining whether to perform a beam update operation based on second feedback information, wherein the second feedback information includes one or more of a hybrid automatic repeat request (HARQ) response and quality information of sidelink channels.

According to an exemplary embodiment of the present invention, a transmitting terminal may transmit sidelink signals and/or channels using one or more beams associated with one or more areas in which receiving terminals participating in a multicast service are located. In other words, a transmitting terminal may transmit one or more beams in one or more particular directions, rather than in all directions. Therefore, transmission delay in the sidelink communication can be reduced, power consumption of the transmission terminal can be reduced, and interference caused by the sidelink communication can be reduced. Accordingly, the performance of the communication system can be improved.

Drawings

Fig. 1 is a conceptual diagram illustrating a V2X communication scenario;

fig. 2 is a conceptual diagram illustrating an exemplary embodiment of a cellular communication system;

fig. 3 is a conceptual diagram illustrating an exemplary embodiment of a communication node constituting a cellular communication system;

fig. 4 is a block diagram illustrating an exemplary embodiment of a user plane protocol stack of a UE performing sidelink communications;

fig. 5 is a block diagram illustrating a first exemplary embodiment of a control plane protocol stack of a UE performing sidelink communications;

fig. 6 is a block diagram illustrating a second exemplary embodiment of a control plane protocol stack of a UE performing sidelink communications;

fig. 7 is a conceptual diagram illustrating a first exemplary embodiment of a sidelink communication method performed in a beam scanning scheme;

fig. 8 is a timing diagram showing the first exemplary embodiment of the beam scanning operation in the time domain;

fig. 9 is a sequence diagram showing a first exemplary embodiment of a side link multicast communication method;

fig. 10 is a timing diagram illustrating a first exemplary embodiment of a group transmission interval; and

fig. 11 is a timing diagram illustrating a second exemplary embodiment of a group transmission interval.

Detailed Description

Embodiments of the invention are disclosed below. However, specific structural and functional details disclosed herein are merely for purposes of describing embodiments of the present invention. Thus, embodiments of the invention may be embodied in many alternate forms and should not be construed as limited to the embodiments of the invention set forth herein.

Accordingly, while the invention is capable of various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that there is no intention to limit the invention to the specific forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. Like reference numerals refer to like elements throughout the description of the figures.

It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of the present invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements present. Other words used to describe the relationship between elements should be interpreted in a similar manner (i.e., "between," "directly between," "adjacent" and "directly adjacent," etc.).

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises," "comprising," "includes" and/or "including," when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

It should be understood that the term "vehicle" or other similar terms as used herein include motor vehicles in general, such as passenger vehicles including Sport Utility Vehicles (SUVs), buses, trucks, various commercial vehicles, watercraft including various watercraft, aircraft, and the like, and include hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen powered vehicles, and other alternative fuel vehicles (e.g., fuel from resources other than petroleum). As referred to herein, a hybrid vehicle is a vehicle having two or more power sources, such as a gasoline powered vehicle and an electric vehicle.

Additionally, it should be understood that one or more of the following methods or aspects thereof may be performed by at least one control unit. The term "control unit" may refer to a hardware device comprising a memory and a processor. The memory is configured to store program instructions and the processor is specifically programmed to execute the program instructions to perform one or more processes described further below. The control unit may control the operation of the units, modules, components, etc., as described herein. Further, it should be understood that the following method may be performed by an apparatus (e.g., a communication node) comprising a control unit in combination with one or more other components, as would be understood by one of ordinary skill in the art.

Furthermore, the control unit of the present invention may be embodied as a non-transitory computer readable medium containing executable program instructions executed by a processor, controller, or the like. Examples of computer readable media include, but are not limited to, ROM, RAM, Compact Disc (CD) -ROM, magnetic tape, floppy disk, flash drive, smart card, and optical data storage. The computer readable recording medium CAN also be distributed throughout a computer network so that the program instructions are stored and executed in a distributed fashion, such as through a telematics server or a Controller Area Network (CAN).

Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. In order to facilitate a general understanding in describing the present invention, like parts are denoted by like reference numerals in the drawings, and a repetitive description thereof will be omitted.

Fig. 1 is a conceptual diagram illustrating a V2X communication scenario.

As shown in fig. 1, V2X communications may include vehicle-to-vehicle (V2V) communications, vehicle-to-infrastructure (V2I) communications, vehicle-to-pedestrian (V2P) communications, vehicle-to-network (V2N) communications, and so forth. V2X communications may be supported by a cellular communication system (e.g., cellular communication system 140), and V2X communications supported by the cellular communication system 140 may be referred to as "cellular-V2X (C-V2X) communications. In particular, the cellular communication system 140 may include a 4G communication system (e.g., an LTE communication system or an LTE-a communication system), a 5G communication system (e.g., an NR communication system), and so on.

The V2V communication may include communication between a first vehicle 100 (e.g., a communication node located in vehicle 100) and a second vehicle 110 (e.g., a communication node located in vehicle 110). Various types of travel information, such as speed, heading, time, location, etc., may be exchanged between the vehicle 100 and the vehicle 110 via the V2V communication. For example, automated driving (e.g., queuing) may be supported based on travel information exchanged via V2V communication. V2V communications supported in the cellular communication system 140 may be performed based on "sidelink" communication technologies (e.g., ProSe and D2D communication technologies, etc.). In particular, communication between vehicle 100 and vehicle 110 may be performed using at least one sidelink channel established between vehicle 100 and vehicle 110.

The V2I communication may include communication between a first vehicle 100 (e.g., a communication node located in the vehicle 100) and infrastructure located at the roadside (e.g., a roadside unit (RSU)) 120. Infrastructure 120 may also include traffic lights or street lights located at the roadside. For example, when performing the V2I communication, the communication may be performed between a communication node located in the first vehicle 100 and a communication node located in a traffic light. Traffic information, travel information, etc. may be exchanged between the first vehicle 100 and the infrastructure 120 via V2I communication. V2I communications supported in the cellular communication system 140 may be performed based on "sidelink" communication technologies (e.g., ProSe and D2D communication technologies, etc.). In particular, the communication between the vehicle 100 and the infrastructure 120 may be performed using at least one sidelink channel established between the vehicle 100 and the infrastructure 120.

The V2P communication may include communication between a first vehicle 100 (e.g., a communication node located in the vehicle 100) and a person 130 (e.g., a communication node carried by the person 130). Travel information of the first vehicle 100 and movement information of the person 130, such as speed, heading, time, location, etc., may be exchanged between the vehicle 100 and the person 130 via V2P communication. A communication node located in the vehicle 100 or carried by the person 130 may generate an alarm indicating a danger by determining a dangerous situation based on the obtained travel information and movement information. V2P communications supported in the cellular communication system 140 may be performed based on sidelink communication techniques (e.g., ProSe and D2D communication techniques, etc.). In particular, communication between the communication nodes located in the vehicle 100 and the communication nodes carried by the person 130 may be performed using at least one sidelink channel established between the communication nodes.

The V2N communication may be a communication between the first vehicle 100 (e.g., a communication node located in the vehicle 100) and a server connected through the cellular communication system 140. V2N communication may be performed based on 4G communication technology (e.g., LTE or LTE-a) or 5G communication technology (e.g., NR). In addition, the V2N communication may be performed based on a Wireless Access (WAVE) communication technology or a Wireless Local Area Network (WLAN) communication technology in a vehicle-mounted environment, the WLAN communication technology being defined in a Wireless Personal Area Network (WPAN) communication technology defined in Institute of Electrical and Electronics Engineers (IEEE)802.11 or IEEE 802.15.

Meanwhile, the cellular communication system 140 supporting V2X communication may be configured as follows.

Fig. 2 is a conceptual diagram illustrating an exemplary embodiment of a cellular communication system.

As shown in fig. 2, the cellular communication system may include an access network, a core network, and the like. The access network may include a base station 210, a relay 220, User Equipments (UEs) 231 to 236, and the like. UEs 231-236 may include communication nodes located in

vehicles

100 and 110 of fig. 1, communication nodes located in infrastructure 120 of fig. 1, communication nodes carried by person 130 of fig. 1, and so forth. When the cellular communication system supports the 4G communication technology, the core network may include a serving gateway (S-GW)250, a Packet Data Network (PDN) gateway (P-GW)260, a Mobility Management Entity (MME)270, and the like.

When the cellular communication system supports the 5G communication technology, the core network may include a User Plane Function (UPF)250, a Session Management Function (SMF)260, an access and mobility management function (AMF)270, and the like. Alternatively, when the cellular communication system operates in a non-independent (NSA) mode, the core network composed of the S-GW 250, the P-GW 260, and the MME 270 may support the 5G communication technology as well as the 4G communication technology, or the core network composed of the UPF 250, the SMF 260, and the AMF 270 may support the 4G communication technology as well as the 5G communication technology.

In addition, when the cellular communication system supports network slicing techniques, the core network may be divided into a plurality of logical network slices. For example, a network slice supporting V2X communication may be configured (e.g., a V2V network slice, a V2I network slice, a V2P network slice, a V2N network slice, etc.), and V2X communication may be supported via a V2X network slice configured in the core network.

A communication node (e.g., base station, relay, UE, S-GW, P-GW, MME, UPF, SMF, AMF, etc.) comprising a cellular communication system may perform communication using at least one communication technique of a Code Division Multiple Access (CDMA) technique, a Time Division Multiple Access (TDMA) technique, a Frequency Division Multiple Access (FDMA) technique, an Orthogonal Frequency Division Multiplexing (OFDM) technique, a filtered OFDM technique, an Orthogonal Frequency Division Multiple Access (OFDMA) technique, a single carrier FDMA (SC-FDMA) technique, a non-orthogonal multiple access (NOMA) technique, a Generalized Frequency Division Multiplexing (GFDM) technique, a filterbank multi-carrier (FBMC) technique, a universal filtered multi-carrier (UFMC) technique, and a Spatial Division Multiple Access (SDMA) technique.

A communication node (e.g., base station, relay, UE, S-GW, P-GW, MME, UPF, SMF, AMF, etc.) comprising a cellular communication system may be configured as follows.

Fig. 3 is a conceptual diagram illustrating an exemplary embodiment of a communication node constituting a cellular communication system.

As shown in fig. 3, the communication node 300 may include at least one processor 310, a memory 320, and a transceiver 330 connected to a network to perform communication. Further, the communication node 300 may further comprise input interface means 340, output interface means 350, storage means 360, etc. Each of the components included in the communication node 300 may communicate with each other when connected via a bus 370.

However, each component included in the communication node 300 may be connected to the processor 310 via a separate interface or a separate bus instead of the common bus 370. For example, the processor 310 may be connected to at least one of the memory 320, the transceiver 330, the input interface device 340, the output interface device 350, and the storage device 360 via a dedicated interface.

Processor 310 may execute at least one instruction stored in at least one of memory 320 and storage 360. The processor 310 may refer to a Central Processing Unit (CPU), a Graphics Processing Unit (GPU) or a dedicated processor on which the method according to embodiments of the present invention is performed. Each of memory 320 and storage 360 may include at least one of volatile storage media and non-volatile storage media. For example, the memory 320 may include at least one of a Read Only Memory (ROM) and a Random Access Memory (RAM).

Referring again to fig. 2, in a communication system, base stations 210 may form macro cells or small cells and may be connected to a core network via an ideal backhaul or a non-ideal backhaul. The base station 210 may transmit signals received from the core network to the UEs 231 to 236 and the relay 220, and may transmit signals received from the UEs 231 to 236 and the relay 220 to the core network.

UEs

231, 232, 234, 235, and 236 may belong to the cellular coverage of base station 210. The

UEs

231, 232, 234, 235, and 236 may connect to the base station 210 by performing a connection establishment procedure with the base station 210. The

UEs

231, 232, 234, 235, and 236 may communicate with the base station 210 after connecting to the base station 210.

The relay 220 may be connected to the base station 210 and may relay communications between the base station 210 and the

UEs

233 and 234. In other words, relay 220 may transmit signals received from base station 210 to UEs 233 and 234, and may transmit signals received from

UEs

233 and 234 to base station 210. UE 234 may belong to both the cellular coverage of base station 210 and the cellular coverage of relay 220, and UE 233 may belong to the cellular coverage of relay 220. That is, UE 233 may be located outside the cellular coverage of base station 210.

UEs

233 and 234 may connect to relay 220 by performing a connection establishment procedure with relay 220.

UEs

233 and 234 may communicate with relay 220 after connecting to relay 220.

The base station 210 and the relay 220 may support multiple-input multiple-output (MIMO) techniques (e.g., single-user (SU) -MIMO, multi-user (MU) -MIMO, massive MIMO, etc.), coordinated multi-point (CoMP) communication techniques, Carrier Aggregation (CA) communication techniques, unlicensed band communication techniques (e.g., Licensed Assisted Access (LAA), enhanced LAA (elaa), etc.), sidelink communication techniques (e.g., ProSe communication techniques, D2D communication techniques), etc. The

UEs

231, 232, 235, and 236 may perform operations corresponding to the base station 210 and operations supported by the base station 210.

UEs

233 and 234 may perform operations corresponding to relay 220 and operations supported by relay 220.

In particular, the base station 210 may be referred to as a node b (nb), an evolved node b (enb), a Base Transceiver Station (BTS), a Radio Remote Head (RRH), a Transmission Reception Point (TRP), a Radio Unit (RU), a roadside unit (RSU), a radio transceiver, an access point, an access node, and so on. The relay 220 may be referred to as a small base station, a relay node, etc. Each of the UEs 231 through 236 may be referred to as a terminal, an access terminal, a mobile terminal, a station, a subscriber station, a mobile station, a portable subscriber station, a node, a device, an On Board Unit (OBU), or the like.

Meanwhile, communication between the UE235 and the UE236 may be performed based on a sidelink communication technique. The sidelink communication may be performed based on a one-to-one scheme or a one-to-many scheme. When performing V2V communications using a sidelink communication technique, UE235 may be a communication node located in first vehicle 100 of fig. 1, and UE236 may be a communication node located in second vehicle 110 of fig. 1. When performing V2I communications using a sidelink communication technique, UE235 may be a communication node located in first vehicle 100 of fig. 1, and UE236 may be a communication node located in infrastructure 120 of fig. 1. When performing V2P communications using a sidelink communication technique, UE235 may be a communication node located in first vehicle 100 of fig. 1, and UE236 may be a communication node carried by person 130 of fig. 1.

The scenario in which sidelink communications are applied may be classified as shown in table 1 below according to the location of the UEs (e.g., UEs 235 and 236) participating in the sidelink communications. For example, the scenario of sidelink communication between UE235 and UE236 shown in fig. 2 may be sidelink communication scenario C.

TABLE 1

Meanwhile, the user plane protocol stack of the UE performing the sidelink communication (e.g., the UEs 235 and 236) may be configured as follows.

Fig. 4 is a block diagram illustrating an exemplary embodiment of a user plane protocol stack of a UE performing sidelink communications.

As shown in fig. 4, the left UE may be UE235 shown in fig. 2, and the right UE may be UE236 shown in fig. 2. The scenario for sidelink communication between UE235 and UE236 may be one of sidelink communication scenarios a-D of table 1. The user plane protocol stack of each of UE235 and UE236 may include a Physical (PHY) layer, a Medium Access Control (MAC) layer, a Radio Link Control (RLC) layer, and a Packet Data Convergence Protocol (PDCP) layer.

The sidelink communications between the UE235 and the UE236 may be performed using a PC5 interface (e.g., a PC5-U interface). A layer-2 Identifier (ID) (e.g., source layer-2 ID, destination layer-2 ID) may be used for sidelink communications, and a layer 2-ID may be an ID configured for V2X communications (e.g., V2X service). Further, in the side link communication, a hybrid automatic repeat request (HARQ) feedback operation may be supported, and an RLC acknowledged mode (RLC AM) or an RLC unacknowledged mode (RLC UM) may be supported.

Meanwhile, the control plane protocol stack of the UEs performing the sidelink communication (e.g., UEs 235 and 236) may be configured as follows.

Fig. 5 is a block diagram illustrating a first exemplary embodiment of a control plane protocol stack of a UE performing sidelink communications, and fig. 6 is a block diagram illustrating a second embodiment of a control plane protocol stack of a UE performing sidelink communications.

As shown in fig. 5 and 6, the left UE may be UE235 shown in fig. 2, and the right UE may be UE236 shown in fig. 2. The scenario for sidelink communication between UE235 and UE236 may be one of sidelink communication scenarios a-D of table 1. The control plane protocol stack shown in fig. 5 may be a control plane protocol stack (e.g., a Physical Sidelink Broadcast Channel (PSBCH)) for transmitting and receiving broadcast information.

The control plane protocol stack shown in fig. 5 may include a PHY layer, a MAC layer, an RLC layer, and a Radio Resource Control (RRC) layer. The sidelink communications between the UE235 and the UE236 may be performed using a PC5 interface (e.g., a PC5-C interface). The control plane protocol stack shown in fig. 6 may be a control plane protocol stack for one-to-one side link communications. The control plane protocol stack shown in fig. 6 may include a PHY layer, a MAC layer, an RLC layer, a PDCP layer, and a PC5 signaling protocol layer.

Meanwhile, channels used in the sidelink communication between the UE235 and the UE236 may include a physical sidelink shared channel (PSCCH), a Physical Sidelink Control Channel (PSCCH), a Physical Sidelink Discovery Channel (PSDCH), and a Physical Sidelink Broadcast Channel (PSBCH). The PSSCH may be used to transmit and receive sidelink data and may be configured in a UE (e.g., UE235 or 236) through higher layer signaling. The PSCCH may be used for transmitting and receiving Sidelink Control Information (SCI) and may also be configured in a UE (e.g., UE235 or 236) through higher layer signaling.

PSDCH can be used for discovery procedures. For example, the discovery signal may be transmitted over the PSDCH. The PSBCH may be used to transmit and receive broadcast information (e.g., system information). In addition, a demodulation reference signal (DM-RS), a synchronization signal, or the like may be used in the sidelink communication between the UE235 and the UE 236.

Meanwhile, the sidelink Transmission Mode (TM) may be classified into sidelink TM 1 to 4 as shown in table 2 below.

TABLE 2

When supporting

sidelink TM

3 or 4, each of the

UEs

235 and 236 may perform sidelink communications using a resource pool configured by the base station 210. A resource pool may be configured for each of the sidelink control information and the sidelink data.

The resource pool for the sidelink control information may be configured based on an RRC signaling procedure (e.g., a dedicated RRC signaling procedure, a broadcast RRC signaling procedure). The resource pool for receiving the sidelink control information may be configured by a broadcast RRC signaling procedure. When the sidelink TM 3 is supported, a resource pool for transmitting sidelink control information may be configured by a dedicated RRC signaling procedure. In particular, the sidelink control information may be transmitted through resources scheduled by the base station 210 within a resource pool configured by a dedicated RRC signaling procedure. When the sidelink TM 4 is supported, the resource pool for transmitting the sidelink control information may be configured by a dedicated RRC signaling procedure or a broadcast RRC signaling procedure. In particular, the sidelink control information may be transmitted through a resource autonomously selected by a UE (e.g., UE235 or 236) within a resource pool configured by a dedicated RRC signaling procedure or a broadcast RRC signaling procedure.

When the sidelink TM 3 is supported, a resource pool for transmitting and receiving sidelink data may not be configured. In particular, the sidelink data may be transmitted and received via resources scheduled by the base station 210. When the sidelink TM 4 is supported, the resource pool for transmitting and receiving sidelink data may be configured by a dedicated RRC signaling procedure or a broadcast RRC signaling procedure. In particular, sidelink data may be transmitted and received over resources autonomously selected by a UE (e.g., UE235 or 236) within a resource pool configured by a dedicated RRC signaling procedure or a broadcast RRC signaling procedure.

Next, a method for transmitting and receiving Sidelink Control Information (SCI) including configuration information for transmission and reception in a communication system (e.g., a cellular communication system) supporting V2X communication as described above will be described. Even when a method (e.g., transmission or reception of a signal) to be performed at a first communication node among the communication nodes is described, a corresponding second communication node may perform a method (e.g., reception or transmission of a signal) corresponding to the method performed at the first communication node. In other words, when describing the operation of the first vehicle, the corresponding second vehicle may perform the operation corresponding to the operation of the first vehicle. In contrast, when the operation of the second vehicle is described, the corresponding first vehicle may perform an operation corresponding to the operation of the second vehicle. In the embodiments described below, the operation of the vehicle may be the operation of a communication node located in the vehicle.

Sidelink communications may be performed using a high frequency band (e.g., millimeter wave band). In particular, the sidelink communication may be performed in a beam scanning scheme. Accordingly, the transmitting terminal can transmit the sidelink signals and/or channels in all directions by rotating the beam. The sidelink signals may be synchronization signals (e.g., synchronization signals/physical broadcast channel (SS/PBCH) blocks) and reference signals used for sidelink communications. For example, the reference signal may be a channel state information reference signal (CSI-RS), a DM-RS, a phase tracking reference signal (PT-RS), a cell specific reference signal (CRS), a Sounding Reference Signal (SRS), a Discovery Reference Signal (DRS), and so on. The sidelink channel may be PSSCH, PSCCH, PSDCH, PSBCH, Physical Sidelink Feedback Channel (PSFCH), or the like. In addition, the sidelink channel may refer to a sidelink channel including a sidelink signal mapped to a specific resource in a corresponding sidelink channel. The sidelink communication may support broadcast services, multicast services, and unicast services.

In the following exemplary embodiments, the sidelink broadcast communication may refer to "sidelink communication performed in a broadcast manner", and the sidelink multicast communication may refer to "sidelink communication performed in a multicast manner". In addition, the side link multicast communication may refer to "side link communication performed in a multicast manner", and the side link unicast communication may refer to "side link communication performed in a unicast manner".

Fig. 7 is a conceptual diagram illustrating a first exemplary embodiment of a side link communication method performed in a beam scanning scheme, and fig. 8 is a timing diagram illustrating the first exemplary embodiment of a beam scanning operation in the time domain.

As shown in fig. 7 and 8, the transmitting terminal 710 may transmit sidelink signals and/or channels in a beam scanning scheme. For example, the transmitting terminal 710 may transmit a sidelink signal and/or a sidelink channel using beam #1 in beam interval #1 and receive a sidelink signal and/or a sidelink channel from a receiving terminal (e.g., receiving terminal # 1721) through beam #1 in beam interval # 1. Further, the transmitting terminal 710 may transmit a sidelink signal and/or a sidelink channel using the beam #2 in the beam interval #2, and receive a sidelink signal and/or a sidelink channel from a receiving terminal through the beam #2 in the beam interval # 2.

For example, the transmitting terminal 710 may perform sidelink communication with the receiving terminal using the beams defined in table 3 below in beam intervals #1 to # 12. Beam scanning intervals including beam intervals #1 to #12 may be periodically configured, and the transmitting terminal 710 may perform sidelink communication using the beams #1 to #12 within the beam scanning intervals.

TABLE 3

Meanwhile, the receiving terminals 721 to 724 may be located in a specific area. For example, receiving terminal # 1721 may be located in a region associated with beam #1 of transmitting terminal 710, receiving terminal # 2722 may be located in a region associated with beam #3 of transmitting terminal 710, receiving terminal # 3723 may be located in a region associated with beam #8 of transmitting terminal 710, and receiving terminal # 4724 may be located in a region associated with beam #9 of transmitting terminal 710. The transmitting terminal 710 can transmit a sidelink signal and/or channel in an omni-direction using the beams #1 to #12 even when the positions of the receiving terminals 721 to 724 are limited to a specific area. Accordingly, unnecessary sidelink signals and/or channels may be transmitted through the beams #2, #4 through #7, and #10 through # 12. Such unnecessary transmission of sidelink signals and/or channels may increase transmission delay, power consumption, and interference. To solve this problem, a method of performing sidelink communication using one or more beams associated with one or more specific areas in which one or more receiving terminals are located is required.

Fig. 9 is a sequence diagram showing a first exemplary embodiment of a side link multicast communication method.

As shown in fig. 9, the communication system may include a base station (not shown), a transmitting terminal, and receiving terminals #1 to # 4. The base station may be the base station 210 shown in fig. 2, the transmitting terminal may be the UE235 shown in fig. 2, and each of the receiving terminals #1 to #4 may be the UE236 shown in fig. 2. The receiving terminals #1 to #4 may be located within or outside the coverage of the base station. In addition, the transmitting terminal may be the transmitting terminal 710 shown in fig. 7, and each of the receiving terminals #1 to #4 may be the receiving terminals #1 to #4 (i.e., 721 to 724) shown in fig. 7. The transmitting terminal and the receiving terminals #1 to #4 may be configured the same as or similar to the communication node 300 shown in fig. 3. The transmitting terminal and the receiving terminals #1 to #4 may support the protocol stacks shown in fig. 4 to 6.

The transmitting terminal and the receiving terminals #1 to #4 may participate in sidelink communication (e.g., sidelink multicast communication). The transmitting and receiving terminals #1 to #4 may be connected to the base station, and may obtain configuration information of sidelink communication (e.g., configuration information of sidelink multicast communication) in an access procedure (e.g., an attach procedure) with the base station. The configuration information for the sidelink communications may include one or more information elements defined in table 4 below. The configuration information for the sidelink communication may be obtained by a combination of one or more of an RRC message, a MAC Control Element (CE), and Downlink Control Information (DCI).

TABLE 4

The transmitting terminal and the receiving terminals #1 to #4 may perform the sidelink communication using the configuration information for the sidelink communication (e.g., the configuration information shown in table 4) received from the base station.

The side-link multicast communication may be initiated by one of the terminals (e.g., the sending terminal). The transmitting terminal may transmit an SS/PBCH block (or PSDCH, reference signal) in a beam scanning scheme (S901). The SS/PBCH block may be an SS/PBCH block configured for sidelink multicast communications. In step S901, a sidelink signal for beam or channel measurement may be transmitted instead of the SS/PBCH block. For example, a synchronization signal (e.g., PSSS, SSSS) or a reference signal (e.g., CSI-RS, DRS (e.g., DRS composed of PSSS and SSSS)) may be transmitted in step S901.

In step S901, the SS/PBCH block may be transmitted within a SL-group bandwidth part (BWP) configured by the base station. Further, the SS/PBCH block may be transmitted based on the beam scanning scheme described with reference to fig. 7 and 8. For example, the transmitting terminal may transmit the SS/PBCH block using a corresponding beam (e.g., one of the beams #1 to # 12) in each of the beam intervals #1 to #12 within the beam scanning interval. The number of repeated transmissions of the SS/PBCH block within one beam interval may be configured by the base station. The SS/PBCH block may include one or more of the information elements defined in table 5 below. One or more information elements (e.g., the information elements defined in table 4) configured by the base station may be included in the SS/PBCH block transmitted from the transmitting terminal.

TABLE 5

The receiving terminals #1 to #4 may receive the SS/PBCH block (or PSDCH, reference signal) from the transmitting terminal by performing a monitoring operation within a beam scanning interval (e.g., a beam scanning interval within the SL-group BWP). The beam scanning interval may be preconfigured by the base station through RRC messages, MAC CE and/or DCI. The receiving terminals #1 to #4 may be receiving terminals participating in the sidelink multicast communication. The receiving terminals that do not participate in sidelink multicast communication may not perform a monitoring operation within a beam scanning interval within the SL-group BWP.

The receiving terminals #1 to #4 may identify information elements (e.g., information elements defined in table 5) included in the SS/PBCH block. The receiving terminals #1 to #4 may identify the quality of beams or signals (e.g., SS/PBCH blocks, PDSCH, reference signals) by performing beam measurement operations based on signals and/or channels received from the transmitting terminal. For example, the receiving terminals #1 to #4 may perform beam measurement operations to identify Channel State Information (CSI), a Channel Quality Indicator (CQI), a Reference Signal Received Power (RSRP), a Reference Signal Received Quality (RSRQ), a signal-to-noise ratio (SNR), and/or a signal-to-interference-and-noise ratio (SINR).

The receiving terminals #1 to #4 may select a beam having the best quality among the beams #1 to #12 of the transmitting terminal based on the measured quality information. Referring again to fig. 7, since the receiving terminal #1 is located in a region corresponding to the beam #1 of the transmitting terminal, the beam #1 may have the best quality among the beams #1 to #12 measured at the receiving terminal # 1. Accordingly, the receiving terminal #1 can select the beam #1 among the beams #1 to #12 of the transmitting terminal. Since the receiving terminal #2 is located in the area corresponding to the beam #3 of the transmitting terminal, the quality of the beam #3 may be the best among the beams #1 to #12 measured at the receiving terminal # 2. Accordingly, the receiving terminal #2 can select the beam #1 among the beams #3 to #12 of the transmitting terminal.

Since the receiving terminal #3 is located in the region corresponding to the beam #8 of the transmitting terminal, the quality of the beam #8 may be the best among the beams #1 to #12 measured at the receiving terminal # 3. Therefore, the receiving terminal #3 can select the beam #1 among the beams #8 to #12 of the transmitting terminal. Since the receiving terminal #4 is located in the region corresponding to the beam #9 of the transmitting terminal, the quality of the beam #9 may be the best among the beams #1 to #12 measured at the receiving terminal # 4. Therefore, the receiving terminal #4 can select the beam #1 among the beams #9 to #12 of the transmitting terminal.

Each of the receiving terminals #1 to #4 may transmit feedback information including an index of the selected beam to the transmitting terminal (S902). The feedback information may further include beam quality information (e.g., CSI, CQI, RSRP, RSRQ, SNR, SINR, etc.), an identifier of a receiving terminal that transmitted the feedback information, and the like. In step S902, the feedback information may be transmitted to the transmitting terminal through resources (e.g., psch, PSFCH) indicated by the feedback configuration information received from the base station. Alternatively, in step S902, the feedback information may be transmitted to the transmitting terminal through resources (e.g., psch, PSFCH) indicated by the feedback configuration information contained in the SS/PBCH block received from the transmitting terminal.

Each of the receiving terminals #1 to #4 may notify the transmitting terminal of the corresponding beam index using a feedback resource (e.g., a resource indicated by feedback configuration information) within a beam interval associated with the index of the selected beam. The receiving terminal #1 may transmit feedback information including information indicating the beam #1 to the transmitting terminal using the feedback resource in the beam interval #1 shown in fig. 8 (e.g., the feedback resource indicated by the SS/PBCH block received in the beam interval # 1), and the receiving terminal #2 may transmit feedback information including information indicating the beam #3 to the transmitting terminal using the feedback resource in the beam interval #3 shown in fig. 8 (e.g., the feedback resource indicated by the SS/PBCH block received in the beam interval # 3).

The receiving terminal #3 may transmit feedback information including information indicating the beam #8 to the transmitting terminal by using the feedback resource in the beam interval #8 shown in fig. 8 (e.g., the feedback resource indicated by the SS/PBCH block received in the beam interval # 8), and the receiving terminal #4 may transmit feedback information including information indicating the beam #9 to the transmitting terminal by using the feedback resource in the beam interval #9 shown in fig. 8 (e.g., the feedback resource indicated by the SS/PBCH block received in the beam interval # 9).

The transmitting terminal may receive feedback information (e.g., beam index, quality information) from the receiving terminals (e.g., receiving terminals #1 to # 4). The transmitting terminal may configure one or more groups for sidelink communication based on the feedback information (S903). For example, the transmitting terminal may determine that all receiving terminals that have transmitted the feedback information are involved in the sidelink multicast communication. In response to receiving the feedback information from the receiving terminals #1 to #4, the transmitting terminal may determine that the receiving terminals #1 to #4 participate in the sidelink multicast communication, and may configure the receiving terminals #1 to #4 participating in the sidelink multicast communication as one or more groups. The number of groups configured in step S903 may be equal to or less than the number indicated by "number of groups" in table 4 or table 5, and the number of terminals included in a group configured in step S903 may be equal to or less than the number indicated by "number of terminals" in table 4 or table 5.

For example, the transmitting terminal may configure the receiving terminals #1 to #4 as a group (hereinafter, referred to as "scene # 1"). Alternatively, the transmitting terminal may configure the receiving terminals #1 to #4 into a plurality of groups (hereinafter, referred to as "scene # 2") in consideration of the positions of the receiving terminals. In scenario #2, the transmitting terminal may configure receiving terminals belonging to the same area into the same group. When the sector area corresponding to the beam of the transmitting terminal is defined as shown in table 6 below, the transmitting terminal may configure receiving terminals #1 and #2 belonging to the sector area #1 as a group #1, and configure receiving terminals #3 and #4 belonging to the sector area #3 as a group # 2.

TABLE 6

	Transmitting a beam of a terminal
		Sector area #1	Beam #1-3
Sector area #2	Beam #4-6
		Sector area #3	Beam #7-9
Sector area #4	Beam #10-12

When step S903 is completed, the transmitting terminal may generate control information for sidelink multicast communication (S904). In scene #1, the control information may include one or more information elements among the information elements defined in table 7 below.

TABLE 7

In the scene #2, the control information of the group #1 may include one or more information elements among the information elements defined in the following table 8, and the control information of the group #2 may include one or more information elements among the information elements defined in the following table 9.

TABLE 8

TABLE 9

In scenario #1, the group transmission interval may be configured as follows.

Fig. 10 is a timing diagram illustrating a first exemplary embodiment of a group transmission interval.

As shown in fig. 10, sidelink multicast communication may be performed between the transmitting terminal and the receiving terminals #1 to #4 within the group transmission interval. The group transmission interval may include a control resource set (CORESET) and a data channel (e.g., psch). The group transmission interval may include a sub transmission interval #1 of the receiving terminal #1, a sub transmission interval #2 of the receiving terminal #2, a sub transmission interval #3 of the receiving terminal #3, and a sub transmission interval of the receiving terminal # 4. The sub-transmission intervals of the respective receiving terminals may be distinguished in the time domain and/or the frequency domain. In each sub-transmission interval, a CORESET (e.g., control channel) and a data channel may be configured. Alternatively, the sub transmission intervals of the respective receiving terminals may not be configured within the group transmission interval.

The group transmission interval may be configured within the SL-group BWP and may be repeated according to a pre-configured period. The start of the group transmission interval may be indicated by an offset from a pre-configured reference point. The reference point in the frequency domain may be a Resource Block (RB) #0 of the SL group BWP or the initial BWP (e.g., subcarrier #0 of Common Resource Block (CRB) # 0). The reference point in the time domain may be the start time of slot #0 or subframe # 0.

The periodicity of the group transmission interval may be one or more time slots, subframes, or radio frames. The length of the group transmission interval may be configured in a unit of a slot or a subframe. The bandwidth of the group transmission interval may be configured in units of RBs or CRBs, and may be equal to or less than the bandwidth of the SL-group BWP.

In scenario #2, the group transmission intervals #1 and #2 may be configured as follows.

As shown in fig. 11, the sidelink multicast communication can be performed between the transmitting terminal and the receiving terminals #1 to #2 belonging to the group #1 within the group transmission interval #1, and the sidelink multicast communication can be performed between the transmitting terminal and the receiving terminals #3 to #4 belonging to the group #2 within the group transmission interval # 2. Each of the group transmission intervals #1 and #2 may include a CORESET (e.g., PSCCH) and a data channel (e.g., PSCCH). The group transmission interval #1 may include a sub transmission interval #1 for the receiving terminal #1 and a sub transmission interval #2 for the receiving terminal # 2. The group transmission interval #2 may include a sub transmission interval #1 for the receiving terminal #3 and a sub transmission interval #2 for the receiving terminal # 4. The sub-transmission intervals of the respective receiving terminals may be distinguished in the time domain and/or the frequency domain. The CORESET and the data channel may be configured in each sub-transmission interval. Alternatively, the sub transmission intervals of the respective receiving terminals may not be arranged within the group transmission intervals #1 and # 2.

The group transmission intervals #1 and #2 may be configured within the SL-group BWP and may be repeated according to a pre-configured period. The group transmission intervals #1 and #2 may be continuously or discontinuously configured. The start of the group transmission intervals #1 and #2 may be indicated by an offset from a pre-configured reference point. The reference point in the frequency domain may be subcarrier #0 of RB #0 (e.g., CRB #0) of the SL group BWP or the initial BWP. The reference point in the time domain may be the start time of slot #0 or subframe # 0.

The period of the group transmission intervals #1 and #2 may be one or more slots, subframes, or radio frames. The lengths of the group transmission intervals 1 and #2 may be set in units of slots or subframes. The bandwidths of the group transmission intervals #1 and #2 may be configured in units of RBs or CRBs, and may be less than or equal to the bandwidth of the SL-group BWP.

Referring back to fig. 9, the transmitting terminal may transmit the control information set in step S904 to the receiving terminals #1 to #4 (S905). The control information may be transmitted to the receiving terminals #1 to #4 through a combination of one or more of RRC messages, MAC CEs, and SCIs. The control information may be transmitted through the beam period defined in table 3 and fig. 8. For example, the transmitting terminal may transmit control information to the receiving terminal #1 in the beam interval #1, transmit control information to the receiving terminal #2 in the beam interval #3, transmit control information to the receiving terminal #3 in the beam interval #8, and transmit control information to the receiving terminal 4 in the beam interval # 9. Alternatively, the control information may be transmitted through the group transmission interval shown in fig. 10 and 11.

The receiving terminals #1 to #4 may receive the control information from the transmitting terminal and may identify information elements contained in the control information. For example, the receiving terminals #1 to #4 may identify the group transmission interval. When step S905 is completed, the sidelink multicast communication may be performed within the group transmission interval (S906).

In scenario #1, the transmitting terminal may transmit SCIs including scheduling information to one or more of the receiving terminals #1 to #4 in a group transmission interval shown in fig. 10. The SCI may indicate psch resources within a group transmission interval. In addition, the SCI may further include trigger information of a beam update operation. In particular, the Cyclic Redundancy Check (CRC) of the SCI may be scrambled with the SL-group-RNTI. Each of the receiving terminals #1 to #4 may perform a monitoring operation using the SL-group RNTI to detect SCIs in a group transmission interval (e.g., core set of the group transmission interval). When the SCI is detected in the group transmission interval, each of the receiving terminals #1 to #4 can transmit sidelink data to the transmitting terminal using the psch indicated by the SCI.

Alternatively, each of the receiving terminals #1 to #4 may receive the sidelink data from the transmitting terminal through the psch indicated by the SCI. Each of the receiving terminals #1 to #4 may transmit an HARQ response (e.g., Acknowledgement (ACK) or negative ACK (nack)) regarding the side link data to the transmitting terminal. The HARQ response may be transmitted within a group transmission interval.

Further, the transmitting terminal may transmit a reference signal to each of the receiving terminals #1 to #4 within the group transmission interval. Each of the receiving terminals #1 to #4 may measure channel quality (e.g., beam quality) based on the reference signals received within the group transmission interval and transmit the measured quality information (e.g., CSI, CQI, RSRP, RSRQ, SNR, SINR, etc.) to the transmitting terminal.

In scenario #2, the transmitting terminal may transmit SCI #1 including scheduling information to the receiving terminals #1 and/or #2 in a group transmission interval #1 shown in fig. 11. SCI #1 may indicate psch resources within group transmission interval # 1. Furthermore, SCI #1 may further include trigger information of the beam update operation. In particular, the CRC of SCI #1 may be scrambled with SL-group-RNTI. Each of the receiving terminals #1 and #2 may perform a monitoring operation using the SL-group RNTI to detect SCI #1 in the group transmission interval #1 (e.g., CORESET of the group transmission interval # 1). When SCI #1 is detected in group transmission interval #1, each of the receiving terminals #1 and #2 can transmit sidelink data to the transmitting terminal using the psch indicated by SCI # 1.

Alternatively, each of the receiving terminals #1 and #2 may receive sidelink data from the transmitting terminal through the psch indicated by SCI # 1. Each of the receiving terminals #1 and #2 may transmit an HARQ response (e.g., ACK or NACK) for the side link data to the transmitting terminal. The HARQ response may be transmitted within the group transmission interval # 1.

Further, the transmitting terminal may transmit a reference signal to each of the receiving terminals #1 and #2 within the group transmission interval # 1. Each of the receiving terminals #1 and #2 may measure channel quality (e.g., beam quality) based on the reference signal received within the group transmission interval #1 and transmit the measured quality information (e.g., CSI, CQI, RSRP, RSRQ, SNR, SINR, etc.) to the transmitting terminal.

In scenario #2, the transmitting terminal may transmit SCI #2 including scheduling information to the receiving terminals #3 and/or #4 in a group transmission interval #1 shown in fig. 11. SCI #2 may indicate psch resources within group transmission interval # 2. Furthermore, SCI #2 may further include trigger information of the beam update operation. In particular, the CRC of SCI #2 may be scrambled with SL-group-RNTI. Each of the receiving terminals #3 and #4 may perform a monitoring operation using the SL-group RNTI to detect SCI #2 in the group transmission interval #2 (e.g., core set of the group transmission interval # 2). When SCI #2 is detected in group transmission interval #2, each of the receiving terminals #3 and #4 can transmit sidelink data to the transmitting terminal using the psch indicated by SCI # 2.

Alternatively, each of the receiving terminals #3 and #4 may receive sidelink data from the transmitting terminal through the psch indicated by SCI # 2. Each of the receiving terminals #3 and #4 may transmit an HARQ response (e.g., ACK or NACK) for the side link data to the transmitting terminal. The HARQ response may be transmitted within group transmission interval # 2.

Further, the transmitting terminal may transmit a reference signal to each of the receiving terminals #2 and #4 within the group transmission interval # 3. Each of the receiving terminals #3 and #4 may measure channel quality (e.g., beam quality) based on the reference signal received within the group transmission interval #2 and transmit the measured quality information (e.g., CSI, CQI, RSRP, RSRQ, SNR, SINR, etc.) to the transmitting terminal.

Meanwhile, the transmitting terminal may determine whether to perform a beam update operation based on feedback information (e.g., HARQ response and quality information) received from the receiving terminals #1 to #4 (S907). For example, the transmitting terminal may determine that a beam update operation is necessary when one or more of the following conditions are satisfied.

-condition 1: number of HARQ-NACKs > threshold #1

-condition 2: channel quality (e.g., CQI) < threshold #2

-condition 3: number of receiving terminals whose channel quality (e.g., CQI) is less than threshold #2 > threshold #3

In response to determining that the beam updating operation is necessary, the transmitting terminal may start again from step S901. Specifically, the group configured in step S903 may be initialized, and the group transmission interval configured in step S904 may be initialized. Accordingly, the transmitting terminal may perform step S901 again after transmitting a message indicating that the sidelink multicast communication has ended.

Alternatively, the triggering of the beam update operation may be performed by the receiving terminals #1 to # 4. For example, when the conditions 1 and/or 2 are satisfied, each of the receiving terminals #1 to #4 may transmit a message requesting triggering of a beam update operation to the transmitting terminal. If a message requesting triggering of a beam update operation is received from one or more of the receiving terminals #1 to #4 participating in the sidelink multicast communication, the transmitting terminal may start from step S901 again.

Exemplary embodiments of the present invention can be implemented as program instructions that can be executed by various computers and recorded on computer-readable media. The computer readable medium may include program instructions, data files, data structures, or a combination thereof. The program instructions recorded on the computer-readable medium may be specially designed and configured for the present invention, or may be publicly known and available to those skilled in the computer software field.

Examples of computer readable media may include hardware devices such as ROM, RAM, and flash memory, which are specially configured to store and execute program instructions. Examples of program instructions include both machine code, such as produced by a compiler, and high-level language code that may be executed by the computer using an interpreter. The above exemplary hardware devices may be configured to operate as at least one software module to perform embodiments of the present invention, and vice versa.

Although embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions, and alterations can be made herein without departing from the scope of the invention.

Claims

1. An operation method of a transmitting terminal in a communication system, the operation method comprising:

transmitting a synchronization signal/physical broadcast channel (SS/PBCH) block for sidelink communication in an omni-direction by using a beam scanning scheme;

receiving first feedback information of the SS/PBCH block from a plurality of receiving terminals; and

transmitting a sidelink channel in a specific direction using a beam of the transmitting terminal, wherein the beam is determined based on the first feedback information,

wherein the transmission area corresponding to the specific direction is narrower than the transmission area corresponding to the omnidirectional direction.

2. The method of operation of claim 1, wherein the SS/PBCH block is transmitted within a beam sweep interval configured by a base station to which the transmitting terminal is connected, and the beam sweep interval is configured within a bandwidth part (BWP) for the sidelink communications.

3. The method of operation of claim 1, wherein the first feedback information comprises a beam index of the transmitting terminal selected based on a beam quality measured in accordance with the SS/PBCH block.

4. The operating method of claim 1, wherein a transmission interval is configured based on the first feedback information, and the sidelink channel is transmitted to the plurality of receiving terminals in the beam scanning scheme within the transmission interval.

5. The method of operation of claim 1, further comprising:

classifying the plurality of receiving terminals into one or more groups based on the positions of the plurality of receiving terminals identified according to the first feedback information,

wherein the sidelink channels are transmitted in the beam scanning scheme within a transmission interval of each of the one or more groups.

6. The method of operation of claim 5, further comprising:

transmitting configuration information of the transmission interval to the plurality of receiving terminals before transmitting the sidelink channel,

wherein the configuration information of the transmission interval includes: information indicating a start of the transmission interval, information indicating a length of the transmission interval, information indicating a bandwidth of the transmission interval, information indicating a period of the transmission interval, and an identifier of one or more of the plurality of receiving terminals that perform the sidelink communication within the transmission interval.

7. The method of operation of claim 1, further comprising:

receiving second feedback information of the side link channel from the plurality of receiving terminals; and

determining whether to perform a beam update operation based on the second feedback information,

wherein the second feedback information comprises one or more of a hybrid automatic repeat request (HARQ) response and quality information for the sidelink channel.

8. The operating method of claim 1, wherein the side link channel comprises a physical side link control channel (PSCCH) and a physical side link shared channel (PSCCH), and the PSCCH includes scheduling information of the PSCCH and trigger information of a beam update operation.

9. An operation method of a reception terminal in a communication system, the operation method comprising:

receiving a synchronization signal/physical broadcast channel (SS/PBCH) block for sidelink communication from a transmitting terminal in a beam scanning interval;

selecting a beam index of the transmitting terminal based on the quality information measured according to the SS/PBCH block;

transmitting first feedback information including the beam index to the transmitting terminal; and

receiving a sidelink channel from the transmitting terminal in a transmission interval configured based on the first feedback information,

wherein the SS/PBCH block is transmitted in an omni-direction of the transmitting terminal in the beam scanning interval, the sidelink channel is transmitted in a specific direction of the transmitting terminal in the transmitting interval, and a transmission region corresponding to the specific direction is narrower than a transmission region corresponding to the omni-direction.

10. The method of operation of claim 9, wherein the SS/PBCH block is received within the beam scanning interval configured by a base station to which the receiving terminal is connected, and the beam scanning interval is configured within a bandwidth part (BWP) for the sidelink communications.

11. The operating method according to claim 9, wherein the transmission interval is configured for a plurality of receiving terminals including the receiving terminal, and the sidelink channel for each of the plurality of receiving terminals is transmitted in the beam scanning scheme within the transmission interval.

12. The method of operation of claim 9, further comprising:

receiving configuration information of the transmission interval from the transmitting terminal before receiving the side link channel,

wherein the configuration information of the transmission interval includes: information indicating a start of the transmission interval, information indicating a length of the transmission interval, information indicating a bandwidth of the transmission interval, and information indicating a period of the transmission interval.

13. The method of operation of claim 9, further comprising:

transmitting second feedback information of the side link channel to the transmitting terminal,

wherein the second feedback information includes one or more of a hybrid automatic repeat request (HARQ) response and quality information of the sidelink channel, and the transmitting terminal determines whether to perform a beam update operation based on the second feedback information.

14. The operating method of claim 9, wherein the side link channel comprises a physical side link control channel (PSCCH) and a physical side link shared channel (PSCCH), and the PSCCH includes scheduling information of the PSCCH and trigger information of a beam update operation.

15. A transmitting terminal that performs sidelink communications, comprising:

a processor; and

a memory storing at least one instruction executable by the processor,

wherein the at least one instruction, when executed by the processor, causes the processor to:

transmitting side link signals for beam measurement in an omni-direction using a beam scanning scheme;

receiving first feedback information of the side link signal from a plurality of receiving terminals; and

16. The transmitting terminal of claim 15, wherein the sidelink signal is transmitted within a beam sweep interval configured by a base station to which the transmitting terminal is connected, and the beam sweep interval is configured within a bandwidth part (BWP) for the sidelink communication.

17. The transmitting terminal of claim 15, wherein a transmission interval is configured based on the first feedback information, and the sidelink channel is transmitted to the plurality of receiving terminals in the beam scanning scheme within the transmission interval.

18. The transmitting terminal of claim 15, wherein the at least one instruction is further configured by the processor to:

19. The transmitting terminal of claim 18, wherein the at least one instruction is further configured by the processor to:

wherein the configuration information of the transmission interval includes information indicating a start of the transmission interval, information indicating a length of the transmission interval, information indicating a bandwidth of the transmission interval, information indicating a period of the transmission interval, and an identifier of one or more reception terminals of the plurality of reception terminals that perform the sidelink communication within the transmission interval.

20. The transmitting terminal of claim 15, wherein the at least one instruction is further configured by the processor to: