WO2025103242A1 - Communication method and communication apparatus - Google Patents

Abstract

A communication method and a communication apparatus. The method comprises: a first terminal device transmitting a reference signal on a plurality of first time units, the reference signal being used for indicating that the current data transmission is a multicast transmission; and transmitting multicast data on at least one second time unit, the at least one second time unit being after the plurality of first time units. The method is conducive to achieving multicast transmission at high frequency, thereby improving data transmission efficiency, and saving signaling overhead.

Description

Communication method and communication device

This application claims priority to the Chinese patent application filed with the China Patent Office on November 17, 2023, with application number 202311546108.6 and application name “Communication Method and Communication Device”, the entire contents of which are incorporated by reference in this application.

Technical Field

The present application relates to the field of communications, and more specifically, to a communication method and a communication device.

Background Art

The communication methods in the communication system may include unicast transmission and multicast transmission. Unicast transmission is when one device and another device form a unicast connection pair to transmit data. Multicast transmission is when one device transmits the same data to multiple devices at the same time. Compared with unicast transmission, multicast transmission can send data to multiple terminal devices in a specific group, so multicast transmission can save signaling overhead.

Taking the multicast transmission in the sidelink (SL) transmission system as an example, the sending device does not need to establish a unicast connection with the receiving device in the group when performing multicast transmission, that is, there is no pairing process, but it is determined according to the source ID and destination ID indicated by the high-level layer. That is, when sending data, the sending device carries the multicast source ID and destination ID in the sidelink control information (SCI) according to the high-level instruction, and the receiving device determines whether the destination ID indicated by its own high-level layer matches the received destination ID. If they match, the receiving device determines to receive the multicast data.

In low frequency (i.e., the first frequency range (frequency range 1, FR1)), the multicast data sent by the sending device can be received by the receiving device, and multicast transmission can be achieved without establishing a link between the sending device and the receiving device. In high frequency (i.e., the second frequency range (frequency range 2, FR2)), data cannot be transmitted directly. In this case, how to achieve multicast transmission has become a technical problem that needs to be solved urgently.

Summary of the invention

The present application provides a communication method and a communication device, which are conducive to realizing multicast transmission at high frequency, thereby improving data transmission efficiency and saving signaling overhead.

In a first aspect, a communication method is provided, comprising: sending a reference signal on multiple first time units, wherein the reference signal is used to indicate that the data transmission is a multicast transmission; and sending multicast data on at least one second time unit, wherein the at least one second time unit is after the multiple first time units.

In a possible implementation manner, the method may be executed by the first terminal device, or by a chip in the first terminal device.

It should be understood that the reference signal is used to indicate that the current data transmission is multicast transmission, and it can also be understood that the reference signal is used to indicate that the data transmitted in at least one second time unit is multicast data.

The second terminal device receives multicast data in at least one second time unit based on the measurement result of the reference signal, which may be specifically: the second terminal device determines the target receiving beam based on the measurement result of the reference signal corresponding to each receiving beam in the multiple receiving beams; and receives multicast data in at least one second time unit using the target receiving beam. Exemplarily, the measurement result may be the RSRP of the reference signal, that is, the second terminal device may determine the target receiving beam based on the RSRP of the reference signal.

Since there is no link between the first terminal device and the second terminal device in the high-frequency scenario and the transmit and receive beams cannot be determined, the first terminal device can first send a reference signal to the second terminal device for the second terminal device to train a target receive beam, that is, first determine the receive beam direction of the multicast data, and then use the target receive beam to receive the multicast data, thereby realizing multicast transmission.

Therefore, the communication method of the embodiment of the present application sends a reference signal indicating that the data transmission is multicast transmission in multiple first time units by the first terminal device, so that the second terminal device receives the reference signal, and determines the target receiving beam based on the measurement result of the reference signal, thereby using the target receiving beam to receive the multicast data from the first terminal device in at least one second time unit. In this way, it is conducive to realizing multicast transmission at high frequency, and further can improve the data transmission efficiency and save signaling overhead.

In combination with the first aspect, in certain implementations of the first aspect, the multiple first time units and the at least one second time unit belong to the same physical layer sidelink feedback channel PSFCH period.

In this way, it is convenient for the first terminal device and the second terminal device to determine the multicast transmission time, and use the same PSFCH period as the data sending period to quickly complete beam scanning and data transmission within the period.

In combination with the first aspect, in some implementations of the first aspect, the multiple first time units are predefined, configured, or preconfigured time units.

In combination with the first aspect, in some implementations of the first aspect, the at least one second time unit is a predefined, configured, or preconfigured time unit.

It should be understood that the above-mentioned pre-definition can be understood as a standard definition, which does not require other equipment configuration (and the network equipment or other terminal equipment cannot be changed), and is information recorded/written in advance in the hardware and/or software of the terminal equipment itself. The above-mentioned configuration can be understood as network equipment configuration and terminal equipment configuration. If it is a network equipment configuration, it can be changed through SIB or RRC signaling; if it is a terminal equipment configuration, it can be changed according to PC5-RRC signaling. The above-mentioned pre-configuration can be understood as information recorded/written in advance in the hardware and/or software of the terminal equipment itself, which is determined by the manufacturer of the equipment and can be changed through software or hardware.

It should also be understood that there may be a corresponding relationship between the at least one second time unit and the multiple first time units, and the second terminal device receives the reference signal on the multiple first time units, and can determine which time unit (i.e., at least one second time unit) to receive the multicast data on according to the corresponding relationship. The corresponding relationship may be predefined, configured, or preconfigured, and the embodiments of the present application do not limit this.

In combination with the first aspect, in certain implementations of the first aspect, the multiple first time units are the first or first two time units of the PSFCH cycle.

Since the second terminal device needs to complete the beam scanning first, it is necessary to uniformly determine the position of at least the first time unit, and at least the first time unit needs to be at the beginning of the PSFCH period.

In combination with the first aspect, in some implementations of the first aspect, the method further includes: sending side control information SCI on a third time unit, wherein the SCI carries information for indicating the at least one second time unit.

It should be understood that the SCI carries information for indicating at least one second time unit, and the third time unit for sending the SCI is before the at least one second time unit. The third time unit may be a time unit in the above-mentioned multiple first time units, or may be a time unit different from the above-mentioned multiple first time units, which is not limited in the embodiments of the present application. Exemplarily, the third time unit may be the first time unit of the PSFCH cycle.

In combination with the first aspect, in some implementations of the first aspect, the method further includes: receiving feedback information from at least one terminal device, wherein the feedback information is used to indicate whether the at least one terminal device successfully receives the multicast data.

Optionally, the feedback information may include ACK information and NACK information, wherein the ACK information is used to indicate that the multicast data is successfully received, and the NACK information is used to indicate that the multicast data is not successfully received. Exemplarily, if the second terminal device receives the multicast data of the first terminal device, if the PSSCH is correctly decoded, the second terminal device determines that the multicast data is successfully received, and sends a PSFCH sequence carrying ACK information to the first terminal device; if the PSSCH is not correctly decoded, the second terminal device determines that the multicast data is not successfully received, and sends a PSFCH sequence carrying NACK information to the first terminal device.

For the first terminal device, only when all second terminal devices in the multicast group feedback that the multicast data is successfully received (for example, all second terminal devices in the multicast group feedback ACK information) will the first terminal device consider that the multicast data transmission is successful, otherwise, the first terminal device will retransmit the multicast data. In this way, the reliability of multicast data transmission can be improved.

It should be understood that the second terminal device can use the beam direction corresponding to the above-mentioned target receiving beam to send the above-mentioned feedback information, and the first terminal device can use the beam direction corresponding to the sending beam of the above-mentioned multicast data to receive the feedback information, but the embodiment of the present application is not limited to this.

In combination with the first aspect, in some implementations of the first aspect, the reference signal includes a channel state information reference signal CSI-RS or a demodulation reference signal DMRS.

In a second aspect, a communication method is provided, comprising: receiving a reference signal on multiple first time units, the reference signal being used to indicate that the data transmission is a multicast transmission; and receiving multicast data on at least one second time unit based on a measurement result of the reference signal.

In a possible implementation manner, the method may be executed by the second terminal device, or by a chip in the second terminal device.

In combination with the second aspect, in certain implementations of the second aspect, the multiple first time units and the at least one second time unit belong to the same physical layer sidelink feedback channel PSFCH period.

In combination with the second aspect, in some implementations of the second aspect, the multiple first time units are predefined, configured, or preconfigured time units.

In combination with the second aspect, in certain implementations of the second aspect, the multiple first time units are the first or first two time units in a PSFCH cycle.

In conjunction with the second aspect, in some implementations of the second aspect, the at least one second time unit is predefined or configured. or preconfigured time units.

In combination with the second aspect, in some implementations of the second aspect, the method further includes: receiving sideline control information SCI on a third time unit, wherein the SCI carries information for indicating the at least one second time unit.

In combination with the second aspect, in certain implementations of the second aspect, receiving multicast data at at least one second time unit based on the measurement results of the reference signal includes: determining a target receiving beam based on the measurement results of the reference signal corresponding to each receiving beam in multiple receiving beams; and receiving multicast data at at least one second time unit using the target receiving beam.

In combination with the second aspect, in some implementations of the second aspect, the method further includes: sending feedback information, where the feedback information is used to indicate whether the multicast data is successfully received.

In combination with the second aspect, in some implementations of the second aspect, the reference signal includes a channel state information reference signal CSI-RS resource.

According to a third aspect, a communication method is provided, comprising: determining a target transmitting beam based on multiple transmitting beams, wherein the direction of the target transmitting beam covers the directions of the multiple transmitting beams, and each transmitting beam in the multiple transmitting beams is a transmitting beam of a first terminal device between a first terminal device and each second terminal device in a plurality of second terminal devices; and sending multicast data to the plurality of second terminal devices in at least one first time unit by using the target transmitting beam.

In a possible implementation manner, the method may be executed by the first terminal device, or by a chip in the first terminal device.

The above-mentioned "coverage" can be understood as: the half-power main lobe width of each of the multiple transmit beams is within the half-power main lobe width of the target transmit beam, or the angle between the maximum radiation direction of the target transmit beam and each of the multiple transmit beams is less than the threshold.

It should be understood that, for a certain second terminal device, the transmission beam and the target reception beam between the first terminal device and the second terminal device are obtained by beam training between the first terminal device and the second terminal device.

In the communication method of the embodiment of the present application, the first terminal device can determine the target transmission beam based on multiple transmission beams in unicast transmission, and use the target transmission beam to send multicast data to multiple second terminal devices in at least one first time unit. Multiple second terminal devices determine the target receiving beam, and use the target receiving beam to receive multicast data in at least one first time unit. In this way, an association relationship between unicast and multicast transmission can be established, so that the first terminal device and multiple second terminal devices can complete multicast transmission through the established unicast transmission, and further improve data transmission efficiency and save signaling overhead.

In combination with the third aspect, in certain implementations of the third aspect, the at least one first time unit belongs to the same physical layer sidelink feedback channel PSFCH period.

In combination with the third aspect, in some implementations of the third aspect, the at least one first time unit is a predefined, configured, or preconfigured time unit.

In combination with the third aspect, in certain implementations of the third aspect, the method further includes: sending side control information SCI to the multiple second terminal devices respectively, wherein the SCI carries information for indicating the at least one first time unit.

In combination with the third aspect, in certain implementations of the third aspect, the method further includes: receiving feedback information from at least one second terminal device among the multiple second terminal devices, wherein the feedback information is used to indicate whether the at least one second terminal device successfully receives the multicast data.

In a fourth aspect, a communication device is provided, for executing the method in any possible implementation of the first aspect, the second aspect, or the third aspect. Specifically, the device includes a unit/module for executing the method in any possible implementation of the first aspect, the second aspect, or the third aspect.

In a fifth aspect, the present application provides another communication device, comprising a processor, which is coupled to a memory and can be used to execute instructions in the memory to implement a method in any possible implementation of the first aspect, the second aspect, or the third aspect above.

Optionally, the communication device further comprises a memory. Optionally, the communication device further comprises a communication interface, and the processor is coupled to the communication interface.

In one implementation, the communication device is a first terminal device. When the communication device is a first terminal device, the communication interface may be a transceiver, or an input/output interface.

In another implementation, the communication device is a chip configured in the first terminal device. When the communication device is a chip configured in the first terminal device, the communication interface may be an input/output interface.

In one implementation, the communication device is a second terminal device. When the communication device is a second terminal device, the communication interface may be a transceiver, or an input/output interface.

In another implementation, the communication device is a chip configured in the second terminal device. When the chip is in a terminal device, the above communication interface can be an input/output interface.

In a sixth aspect, a processor is provided, comprising: an input circuit, an output circuit, and a processing circuit. The processing circuit is used to receive a signal through the input circuit and transmit a signal through the output circuit, so that the processor executes the method in any possible implementation of the first aspect, the second aspect, or the third aspect.

In the specific implementation process, the processor can be a chip, the input circuit can be an input pin, the output circuit can be an output pin, and the processing circuit can be a transistor, a gate circuit, a trigger, and various logic circuits. The input signal received by the input circuit can be, for example, but not limited to, received and input by a receiver, and the signal output by the output circuit can be, for example, but not limited to, output to a transmitter and transmitted by the transmitter, and the input circuit and the output circuit can be the same circuit, which is used as an input circuit and an output circuit at different times. The embodiments of the present application do not limit the specific implementation methods of the processor and various circuits.

In a seventh aspect, a processing device is provided, comprising a processor and a memory. The processor is used to read instructions stored in the memory, and can receive signals through a receiver and transmit signals through a transmitter to execute the method in any possible implementation of the first aspect, the second aspect, or the third aspect.

Optionally, the number of the processors is one or more, and the number of the memories is one or more.

Optionally, the memory may be integrated with the processor, or the memory may be provided separately from the processor.

In the specific implementation process, the memory can be a non-transitory memory, such as a read-only memory (ROM), which can be integrated with the processor on the same chip or can be separately set on different chips. The embodiments of the present application do not limit the type of memory and the setting method of the memory and the processor.

It should be understood that the relevant data interaction process, such as sending indication information, can be a process of outputting indication information from a processor, and receiving capability information can be a process of receiving input capability information from a processor. Specifically, the processed output data can be output to a transmitter, and the input data received by the processor can come from a receiver. Among them, the transmitter and the receiver can be collectively referred to as a transceiver.

The processing device in the seventh aspect mentioned above can be a chip. The processor can be implemented by hardware or by software. When implemented by hardware, the processor can be a logic circuit, an integrated circuit, etc.; when implemented by software, the processor can be a general-purpose processor, which is implemented by reading the software code stored in the memory. The memory can be integrated in the processor or can be located outside the processor and exist independently.

In an eighth aspect, a computer program product is provided, comprising: a computer program (also referred to as code, or instruction), which, when executed, enables a computer to execute a method in any possible implementation of the first aspect, the second aspect, or the third aspect.

In the ninth aspect, a computer-readable storage medium is provided, which stores a computer program (also referred to as code, or instructions). When the computer-readable storage medium is run on a computer, the computer executes a method in any possible implementation of the first aspect, the second aspect, or the third aspect.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of a communication system provided in an embodiment of the present application;

FIG2 is a schematic diagram of an SL system provided in an embodiment of the present application;

FIG3 is a schematic diagram of a schematic diagram of a SL time slot structure provided in an embodiment of the present application;

4 is a schematic diagram of the time-frequency position of a reference signal in a physical resource module PRB provided in an embodiment of the present application;

FIG5 is a schematic diagram of resource occupancy of a PSFCH provided in an embodiment of the present application;

FIG6 is a schematic diagram of three processes of beam management provided in an embodiment of the present application;

7 is a schematic diagram of multiple terminal devices performing unicast transmission according to an embodiment of the present application;

8 is a schematic diagram of a plurality of terminal devices performing multicast transmission according to an embodiment of the present application;

FIG9 is a schematic flow chart of a communication method provided in an embodiment of the present application;

10 is a schematic diagram of multicast transmission of multiple terminal devices in the same PSFCH cycle according to an embodiment of the present application;

FIG11 is a schematic flow chart of another communication method provided in an embodiment of the present application;

12 is a schematic diagram of a plurality of terminal devices determining a multicast transmission beam through a unicast transmission beam according to an embodiment of the present application;

13 is a schematic diagram of multicast transmission of multiple terminal devices in the same PSFCH cycle according to an embodiment of the present application;

FIG14 is a schematic block diagram of a communication device provided in an embodiment of the present application;

FIG15 is a schematic block diagram of another communication device provided in an embodiment of the present application.

DETAILED DESCRIPTION

The technical solution in this application will be described below in conjunction with the accompanying drawings.

In order to clearly describe the technical solutions of the embodiments of the present application, in the embodiments of the present application, words such as "first" and "second" are used to distinguish the same or similar items with substantially the same functions and effects. Those skilled in the art can understand that words such as "first" and "second" do not limit the quantity and execution order, and words such as "first" and "second" do not necessarily limit the difference.

It should be noted that, in this application, words such as "exemplarily" or "for example" are used to indicate examples, illustrations or explanations. Any embodiment or design described as "exemplarily" or "for example" in this application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplarily" or "for example" is intended to present related concepts in a specific way.

In addition, "at least one" means one or more, and "plurality" means two or more. "And/or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and/or B can mean: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. The character "/" generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b and c can mean: a, or b, or c, or a and b, or a and c, or b and c, or a, b and c, where a, b, c can be single or multiple.

The technical solutions of the embodiments of the present application can be applied to various communication systems, such as: long term evolution (LTE) system, LTE frequency division duplex (FDD) system, LTE time division duplex (TDD), universal mobile telecommunication system (UMTS), worldwide interoperability for microwave access (WiMAX) communication system, fifth generation (5G) system or new radio (NR), future evolved communication systems, such as sixth generation (6G) system, etc.

The technical solution provided in this application can also be applied to machine type communication (MTC), long term evolution-machine (LTE-M), device to device (D2D) network, machine to machine (M2M) network, Internet of Things (IoT) network or Internet of Vehicles. Among them, the communication methods in the Internet of Vehicles system are collectively referred to as vehicle to other devices (vehicle to X, V2X, X can represent anything). Cellular vehicle-to-everything (C-V2X) is a V2X communication technology developed based on cellular systems. It utilizes and enhances current cellular network functions and elements to achieve low-latency and high-reliability communication between various nodes in the vehicle network. V2X may include: vehicle to vehicle (V2V) communication, vehicle to infrastructure (V2I) communication, vehicle to pedestrian (V2P) communication or vehicle to network (V2N) communication. With the evolution of cellular systems from 4G LTE to 5G, C-V2X evolves from LTE-V2X to NR-V2X. NR-V2X can support lower transmission latency, more reliable communication transmission, higher throughput and better user experience, meeting the needs of a wider range of application scenarios. Furthermore, the vehicle-to-vehicle communication technology supported by V2X can be extended to device-to-device (D2D) communication under any system. The solution of the present application can also be applied to scenarios such as relay and cooperation between terminals.

The technical solution provided in this application can also be applied to indoor commercial scenarios, such as communication between smartphones and smart screens, communication between smartphones and VR glasses, etc.

To facilitate understanding of the embodiments of the present application, a communication system applicable to the embodiments of the present application is first introduced in conjunction with Figure 1.

FIG1 shows a schematic diagram of a communication system 100 of an embodiment of the present application. As shown in FIG1 , the communication system 100 includes: a terminal device 110 and a terminal device 120. The terminal device 110 and the terminal device 120 can communicate with each other through a sidelink communication technology, such as sending signaling and/or data. Optionally, the communication system 100 also includes: a network device 130. The terminal device 110 and the network device 130 can communicate with each other through a wireless air interface, and the terminal device 120 and the network device 130 can also communicate with each other through a wireless air interface.

It should be understood that the terminal device 110 or the terminal device 120 or the network device 130 can be configured with multiple antennas, and the multiple antennas can include at least one transmitting antenna for sending signals and at least one receiving antenna for receiving signals. In addition, the terminal device 110 or the terminal device 120 or the network device 130 also additionally includes a transmitter chain and a receiver chain. It can be understood by those skilled in the art that they can all include multiple components related to signal transmission and reception (such as processors, modulators, multiplexers, demodulators, demultiplexers or antennas, etc.). Therefore, the network device 130 and the terminal device 110 (or the terminal device 120) can communicate through multi-antenna technology.

The terminal device 110 and the terminal device 120 can communicate with each other through the PC5 interface between the devices. The communication between the terminal devices in this application is applicable to communication scenarios with network coverage and without network coverage. and terminal device 120 are both within the coverage of network device 130; in another communication scenario, terminal device 110 is within the coverage of network device 130, and terminal device 120 is not within the coverage of network device 130; in yet another communication scenario, both terminal device 110 and terminal device 120 are not within the coverage of network device 130.

It should be understood that Figure 1 is only a schematic diagram, and the communication system 100 may also include other network devices, such as wireless relay devices and wireless backhaul devices, which are not shown in Figure 1. The embodiment of the present application does not limit the number of network devices and terminal devices included in the communication system 100.

In the embodiment of the present application, the network device can be any device with wireless transceiver function. The network device includes but is not limited to: evolved Node B (eNB), radio network controller (RNC), Node B (NB), base station controller (BSC), base transceiver station (BTS), home base station (e.g., home evolved Node B, or home Node B, HNB), baseband unit (BBU), wireless fidelity (wireless fidget) and so on. The invention relates to an access point (AP) in a wireless network, such as an access point (AP), a wireless relay node, a wireless backhaul node, a transmission point (TP) or a transmission and reception point (TRP) in a 5G (e.g., NR) system, and can also be a gNB in a 5G (e.g., NR) system, or a transmission point (TRP or TP), one or a group of (including multiple antenna panels) antenna panels of a base station in a 5G system, or can also be a network node constituting a gNB or a transmission point, such as a baseband unit (BBU) or a distributed unit (DU).

In some deployments, the gNB may include a centralized unit (CU) and a DU. The gNB may also include an active antenna unit (AAU). The CU implements some of the functions of the gNB, and the DU implements some of the functions of the gNB. For example, the CU may be responsible for processing non-real-time protocols and services, such as the functions of the radio resource control (RRC) layer, the service data adaptation protocol (SDAP) layer, and/or the packet data convergence protocol (PDCP) layer. The DU may be responsible for processing physical layer protocols and real-time services. For example, the functions of the radio link control (RLC) layer, the media access control (MAC) layer, and the physical (PHY) layer may be implemented. A DU may be connected to only one CU or to multiple CUs, and a CU may be connected to multiple DUs. The CU and DU may communicate through the F1 interface. The AAU may implement some physical layer processing functions, RF processing, and related functions of active antennas. Since the information of the RRC layer will eventually be delivered to the PHY layer and become the information of the PHY layer, or be converted from the information of the PHY layer, therefore, under this architecture, high-level signaling, such as RRC layer signaling, can also be considered to be sent by DU, or by DU+AAU.

It is understandable that the network device may be a device including one or more of a CU node, a DU node, and an AAU node. In addition, the CU may be classified as a network device in an access network (radio access network, RAN), or the CU may be classified as a network device in a core network (core network, CN), which is not limited in this application.

The network equipment provides services for the cell, and the terminal equipment communicates with the cell through the transmission resources (for example, frequency domain resources, or spectrum resources) allocated by the network equipment. The cell can belong to a macro base station (for example, macro eNB or macro gNB, etc.) or a base station corresponding to a small cell. The small cells here may include: metro cell, micro cell, pico cell, femto cell, etc. These small cells have the characteristics of small coverage and low transmission power, and are suitable for providing high-speed data transmission services.

In an embodiment of the present application, the terminal device may also be referred to as user equipment (UE), access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent or user device.

The terminal device may be a device that provides voice/data connectivity to users, such as a handheld device or vehicle-mounted device with wireless connection function. At present, some examples of terminals may include: mobile phones, tablet computers, computers with wireless transceiver functions (such as laptops, PDAs, etc.), mobile Internet devices (MIDs), virtual reality (VR) devices, augmented reality (AR) devices, wireless terminals in industrial control, wireless terminals in self-driving, wireless terminals in remote medical, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, wireless terminals in smart homes, cellular phones, cordless phones, session initiation protocol (SIP) phones, wireless local loop (WLL) stations, personal digital assistants (PDAs), handheld devices with wireless communication functions, computing devices or other processing devices connected to wireless modems, vehicle-mounted devices, wearable devices, terminal devices in 5G networks or future evolved public land mobile communication networks (public land mobile network, PLMN) Terminal equipment in, etc.

Among them, wearable devices can also be called wearable smart devices, which are a general term for the intelligent design and development of wearable devices for daily wear using wearable technology, such as glasses, gloves, watches, clothing and shoes. Wearable devices are portable devices that are worn directly on the body or integrated into the user's clothes or accessories. Wearable devices are not only hardware devices, but also realize powerful functions through software support, data interaction, and cloud interaction. Broadly speaking, wearable smart devices include full-featured, large-sized, and independent of smartphones to achieve complete or partial functions, such as smart watches or smart glasses, as well as those that only focus on a certain type of application function and need to be used in conjunction with other devices such as smartphones, such as various smart bracelets and smart jewelry for vital sign monitoring.

In addition, the terminal device can also be a terminal device in the Internet of Things (IoT) system. IoT is an important part of the future development of information technology. Its main technical feature is to connect objects to the network through communication technology, thereby realizing an intelligent network of human-machine interconnection and object-to-object interconnection. IoT technology can achieve massive connections, deep coverage, and terminal power saving through narrow band (NB) technology, for example.

In addition, terminal devices can also include sensors such as smart printers, train detectors, and gas stations. Their main functions include collecting data (part of the terminal equipment), receiving control information and downlink data from network devices, and sending electromagnetic waves to transmit uplink data to network devices.

In the embodiment of the present application, the terminal device or network device includes a hardware layer, an operating system layer running on the hardware layer, and an application layer running on the operating system layer. The hardware layer includes hardware such as a central processing unit (CPU), a memory management unit (MMU), and a memory (also called main memory). The operating system can be any one or more computer operating systems that implement business processing through processes, such as Linux operating system, Unix operating system, Android operating system, iOS operating system, or Windows operating system. The application layer includes applications such as browsers, address books, word processing software, and instant messaging software. In addition, the embodiment of the present application does not specifically limit the specific structure of the execution subject of the method provided in the embodiment of the present application. As long as it can communicate according to the method provided in the embodiment of the present application by running a program that records the code of the method provided in the embodiment of the present application, for example, the execution subject of the method provided in the embodiment of the present application can be a terminal device or a network device, or a functional module in the terminal device or the network device that can call and execute a program.

In addition, various aspects or features of the present application can be implemented as methods, devices or products using standard programming and/or engineering techniques. The term "product" used in this application covers computer programs that can be accessed from any computer-readable device, carrier or medium. For example, computer-readable media may include, but are not limited to: magnetic storage devices (e.g., hard disks, floppy disks or tapes, etc.), optical disks (e.g., compact discs (CDs), digital versatile discs (DVDs), etc.), smart cards and flash memory devices (e.g., erasable programmable read-only memories (EPROMs), cards, sticks or key drives, etc.). In addition, the various storage media described herein may represent one or more devices and/or other machine-readable media for storing information. The term "machine-readable medium" may include, but is not limited to, wireless channels and various other media capable of storing, containing and/or carrying instructions and/or data.

To facilitate understanding, the following terms related to the embodiments of the present application are first introduced.

1. NR sidelink (SL) system

Under network coverage, the terminal device can obtain SL resource pool (resource pool) configuration information and/or SL bandwidth part (bandwidth part, BWP) configuration information by receiving the system information block (system information block, SIB) of the network device, the cell-level (cell-specific) radio resource control (radio resource control, RRC) signaling or the terminal device user level (UE-specific) RRC signaling. The terminal device can also use the pre-configured SL resource pool configuration information or SL BWP configuration information. The SL BWP configuration information may include SL resource pool information, which is used to configure the number of resource pools included in the BWP. The SL BWP configuration information may include SL bandwidth information, which is used to indicate the bandwidth size for SL communication, for example, indicating that the SL bandwidth is 20 megahertz (MHz).

In the NR SL system, SCI is divided into first-level SCI and second-level SCI. The physical sidelink control channel (PSCCH) carries the first-level SCI, which is used to schedule the second-level SCI and the physical sidelink shared channel (PSSCH). Since SL is a distributed system, the terminal device needs to correctly decode the first-level SCI before decoding the second-level SCI and PSSCH. Figure 2 shows the distribution of PSCCH in the time domain and frequency domain. As shown in Figure 2, PSCCH may exist in each sub-channel in each time slot, that is, the time domain starting position of a PSCCH is the second symbol for SL transmission in each time slot, and the length can be 2 or 3 symbols (determined by the resource pool configuration information), and the frequency domain position is the smallest physical resource block (PRB) index of each sub-channel, and the length is at least 10 PRBs (determined by the resource pool configuration information) but not more than the size of the sub-channel. It should be understood that the first symbol in each time slot in Figure 2 is an automatic gain control (AGC) symbol.

In the first level SCI, the frequency domain resource assignment field and the time domain resource assignment field are The resource reservation period (resource reservation period) field is used to indicate the resources for periodic reservation of PSSCH transmission. The value of the resource reservation period (resource reservation period) field is configured, preconfigured, or predefined by the network device. For example, the value of the resource reservation period (resource reservation period) field is determined by sl-ResourceReservePeriod1 in the RRC signaling indication. The format of the second-stage SCI is indicated by the ^2nd- stage SCI format field in the first-stage SCI.

The existing SL channel state information reference signal (channel state information reference signal) of the first frequency range (frequency range 1, FR1) is based on the CSI-RS design of the Rel-15 Uu interface. The SL CSI-RS configuration is selected by the transmitting device and provided to the receiving device through the PC5-RRC configuration. The SL CSI-RS configuration includes the resource mapping mode and the number of antenna ports of the SL CSI-RS. In NR V2X, the resource mapping of the SL CSI-RS in the PRB is based on the CSI-RS resource mapping mode in the NR Uu interface, which supports up to 2 antenna ports (for example, in NR V2X, the SL in the PSSCH can support up to two streams), and the frequency domain density is 1, that is, one CSI-RS is configured on each resource block.

Figure 3 is a schematic diagram of the time slot structure of Rel-16 SL, which includes AGC, PSCCH, PSSCH, demodulation reference signal (DMRS), guard interval (GAP), etc. SL CSI-RS supports unicast transmission and is sent with data in the PSSCH area of the transmit time slot. At the same time, SL CSI-RS is not transmitted on symbols containing PSCCH, second-level SCI or PSSCH DMRS.

FIG4 is a schematic diagram of the time-frequency position of CSI-RS in PRB. Each of the 30 PRBs shown in the figure uses the same mode for SL CSI-RS. For one of the PRBs, CSI-RS occupies 2 ports, the time domain starting position is symbol 9, and the frequency domain starting position is subcarrier 5. Therefore, as shown in FIG4, CSI-RS is located at symbol 9, subcarrier 5, and subcarrier 6 in the PRB. The GAP in FIG4 is a guard interval.

2. Hybrid automatic repeat request (HARQ)-acknowledgement (ACK) feedback

NR-V2X supports physical layer HARQ-ACK feedback, that is, for a PSSCH transmission, if the transmitting device carries HARQ-ACK feedback enable information in the control information, the receiving device can feedback the corresponding ACK information or negative acknowledgment (NACK) information according to the PSSCH decoding result. Among them, ACK/NACK information can be transmitted through the physical sidelink feedback channel (PSFCH).

PSFCH channel resources are periodic resources configured in the resource pool. It can be 0, 1, 2, or 4. It indicates that there is no PSFCH resource configuration in the resource pool and PSFCH transmission is not enabled in the resource pool, that is, physical layer HARQ feedback is not supported. Indicates that within a time window, There is one PSFCH feedback slot for each SL slot.

Figure 5 is a schematic diagram of PSFCH resource occupancy. The first row of Figure 5 shows the distribution of PSFCH in a time slot. As shown in Figure 5, in the time slot where the physical resource of PSFCH is located, PSFCH occupies the last two symbols before GAP. As shown in Figure 5, if PSFCH feedback resources are configured in the resource pool, each PSFCH feedback resources are configured once per time slot. If the PSFCH period is 1, Then each time slot will be configured with a PSFCH feedback resource as shown in the first row of Figure 5; if the PSFCH period is 2, that is Then, PSFCH feedback resources will be configured once every 2 time slots as shown in the first row of Figure 5; if the PSFCH period is 4, that is, Then, a PSFCH feedback resource will be configured once every 4 time slots as shown in the first row of FIG. 5 .

Specifically, the process of determining the PSFCH resource corresponding to each subchannel is as follows:

(1) The resource pool is configured with a bitmap of PSFCH frequency domain resources to indicate whether a specific PRB on the frequency domain resources of the resource pool can be used as a PSFCH resource. That is, the length of the bit information contained in the bitmap is equal to the number of PRBs in the resource pool. A 1 in the bitmap indicates that the corresponding PRB can be used for PSFCH transmission, and a 0 indicates that the corresponding PRB resource cannot be used for PSFCH transmission.

(2) Because each Each PSSCH time slot corresponds to one PSFCH feedback time slot. For a resource pool containing N _subch subchannels, the number of PSFCH feedback resources corresponding to each subchannel is in Indicates the number of PRBs of the PSFCH frequency domain resources, that is, the total number of bits with a value of 1 in the bit map indicating the PSFCH frequency domain resources.

(3) Considering the decoding capability limitation of the receiving device, the receiving device cannot provide feedback immediately after receiving the PSSCH. Therefore, the standard defines a PSSCH feedback time interval K, that is, the PSSCH transmits the PSFCH in the first available time slot containing the PSFCH resource, which is at least K time slots away from the time slot where the PSSCH is located. The value of K is configured through high-level parameters.

(4) The PSFCH available resources within a PSFCH feedback time slot are sequentially allocated to each subchannel within the feedback cycle in the time domain first and then the frequency domain.

NR-V2X supports HARQ feedback in unicast and multicast scenarios. In the unicast scenario, a transmitter and a receiver form a unicast connection pair. After the receiver correctly receives a control message from the transmitter, it responds according to the control message. If the PSSCH is decoded correctly, the PSFCH sequence carrying ACK information is sent to the transmitting device, otherwise the PSFCH sequence carrying NACK information is fed back. In the multicast scenario, if the terminal device in the group can correctly decode the PSCCH corresponding to the PSSCH, according to the HARQ enable indication information of the control information, if the PSSCH decoding fails, the terminal device in the group feeds back the PSFCH sequence carrying NACK information, otherwise the PSFCH sequence carrying NACK information is fed back.

3. Beam management

Beam management is an important technology proposed by 5G NR for the second frequency range (frequency range 2, FR2). It refers to the process by which network equipment and terminal equipment obtain and maintain a set of beams for sending and receiving. It is a reference workflow for beamforming in multiple-input multiple-output (MIMO) systems. The frequency range of FR1 is 410MHz-7125 MHz, and the frequency range of FR2 is 24250MHz-52600 MHz.

FIG6 shows the three processes of beam management. As shown in FIG6 , beam management can be divided into three states according to the working state. The operations of each state are summarized as follows:

(a) The terminal device measures the transmission beam set of the network device and selects the transmission beam of the network device and the receiving beam of the terminal device;

(b) Based on (a) in FIG6 , the terminal device measures a smaller set of transmission beams (beamlets) of the network device to improve the transmission beams of the network device;

(c) The terminal device uses different receiving beams to measure the transmitting beam of the same network device and improve the receiving beam of the terminal device itself.

Based on the above operations, downlink beam management can be carried out, and its basic process is as follows: the network device configures up to 64 beam directions, each beam direction corresponds to a synchronization signal block (SSB) and the time-frequency resources that the terminal device should use when reporting the beam. The network device sends SSBs in each direction in a scanning manner, and the terminal device performs beam measurement to obtain the reference signal received power (RSRP) of the SSB. After that, the terminal device selects an SSB set by comparing the RSRP, and reports the SSB sequence number and the corresponding RSRP in the set to the network device on the given time-frequency resource. The network device can use the reported information to perform beam determination.

In order to realize the transmission beam training shown in (b) of Figure 6, the network device can allocate K _S CSI-RS resources to K _S transmission beams, and then send these CSI-RS resources out by periodic beam scanning. Among these CSI-RS resources, the maximum number of CSI-RS ports is 2, and other uncertain resource mapping information needs to be configured by the network device and indicated to the terminal device through RRC signaling. At the same time, the network device only sends CSI-RS resources in a single beam direction at a certain moment. The terminal device performs beam measurement to obtain the CSI-RS reference signal received power RSRP and obtains the CSI-RS resource indicator (CSI-RS resource indicator, CRI). After measuring RSRP, the terminal device selects one or more RSRP values and the corresponding CRI by comparison and reports them to the network device on a given time-frequency resource. The network device can use the report information to determine the transmission beam to be used.

A similar process can also be used for uplink beam management, which will not be described here.

The communication methods in the communication system may include unicast transmission and multicast transmission. Unicast transmission is when one device and another device form a unicast connection pair to transmit data. Multicast transmission is when one device transmits the same data to multiple devices at the same time. Compared with unicast transmission, multicast transmission can send data to multiple terminal devices in a specific group, so multicast transmission can save signaling overhead.

Taking the multicast transmission in the sidelink (SL) transmission system as an example, the sending device does not need to establish a unicast connection with the receiving device in the group when performing multicast transmission, that is, there is no pairing process, but it is determined according to the source ID and destination ID indicated by the high-level layer. That is, when sending data, the sending device carries the multicast source ID and destination ID in the sidelink control information (SCI) according to the high-level instruction, and the receiving device determines whether the destination ID indicated by its own high-level layer matches the received destination ID. If they match, the receiving device determines to receive the multicast data.

In low frequency (i.e., the first frequency range (frequency range 1, FR1)), the multicast data sent by the sending device can be received by the receiving device, and multicast transmission can be achieved without establishing a link between the sending device and the receiving device. Taking UE as an example, Figure 7 shows multicast transmission in the FR1 scenario, UE 1 is the sending device of multicast data, UE 2, UE 3, UE 4 and UE 5 are the receiving devices of multicast data, UE 1 sends multicast data, and UEs in any direction (i.e., UE 2, UE 3, UE 4 and UE 5) can receive the multicast data.

In high frequency (i.e., the second frequency range (frequency range 2, FR2)), beams are generally used for transmission. Taking UE as an example, Figure 8 shows multicast transmission in the FR2 scenario. UE 1 is the transmitter of multicast data, and UE 2, UE 3, UE 4 and UE 5 are the receivers of multicast data. The transmit beam of UE 1 and the receive beams of UE 2, UE 3, UE 4 and UE 5 are all directional and have the same A time unit can only send and receive beams in the same direction. Therefore, when there is no connection between UE 1 and other UEs (such as UE 2, UE 3, UE 4 or UE 5), other UEs may not be able to determine in which time unit and which beam direction to receive multicast data, which will cause UE 1 and other UEs to be unable to perform multicast transmission.

In view of this, the present application proposes a communication method and a communication device, wherein a transmitting end device can send a reference signal for indicating that the current data transmission is a multicast transmission in multiple first time units, and can send multicast data in at least one second time unit. A receiving end device can receive the reference signal in multiple first time units, and can receive the multicast data in at least one second time unit based on the measurement result of the reference signal. The method is conducive to realizing multicast transmission at high frequency, and can further improve data transmission efficiency and save signaling overhead.

The communication method and communication device provided by the present application will be described in detail below in conjunction with the accompanying drawings. It should be understood that the technical solution of the present application can be applied to a wireless communication system, for example, the communication system 100 shown in Figure 1. Two communication devices in the wireless communication system may have a wireless communication connection relationship, and one of the two communication devices may correspond to the terminal device 120 shown in Figure 1, such as, it may be the terminal device 120 shown in Figure 1, or it may be a chip configured in the terminal device; the other communication device of the two communication devices may correspond to the terminal device 130 shown in Figure 1, such as, it may be the terminal device 130 shown in Figure 1, or it may be a chip configured in the terminal device.

In the following, without loss of generality, the multicast transmission method provided by the embodiment of the present application is described in detail by taking the interaction process between the first terminal device and the second terminal device as an example. The first terminal device is a sending end device of the multicast data, and the second terminal device is a receiving end device of the multicast data. The number of the second terminal devices can be one or more, and the embodiment of the present application does not limit this.

In the present application, "sending information to multiple second terminal devices" can be understood as the destination of the information being multiple second terminal devices, and may include directly or indirectly sending information to multiple second terminal devices. "Receiving information from a first terminal device" can be understood as the source of the information being the first terminal device, and may include directly or indirectly receiving information from the first terminal device. The information may be processed as necessary between the source and destination of the information transmission, but the destination can understand the valid information from the source. Similar expressions in the present application can be understood similarly and will not be repeated here.

FIG9 shows a communication method 900 provided in an embodiment of the present application. The method 900 can be applied to the communication system 100 shown in FIG1 , and can also be applied to other communication systems, which is not limited in the embodiment of the present application. The method 900 includes the following steps:

S901, a first terminal device sends a reference signal in a plurality of first time units, the reference signal being used to indicate that the current data transmission is a multicast transmission. Correspondingly, a second terminal device receives the reference signal in a plurality of first time units.

S902, the first terminal device sends multicast data in at least one second time unit, the at least one second time unit being after the plurality of first time units. Correspondingly, the second terminal device receives multicast data in at least one second time unit based on the measurement result of the reference signal.

The above-mentioned second terminal device receives multicast data in at least one second time unit based on the measurement result of the reference signal. Specifically, it can be: the second terminal device determines the target receiving beam based on the measurement result of the reference signal corresponding to each receiving beam in multiple receiving beams; and uses the target receiving beam to receive multicast data in at least one second time unit.

Exemplarily, the above measurement result may be the RSRP of the reference signal, that is, the second terminal device may determine the target receiving beam according to the RSRP of the reference signal. For example, the target receiving beam may be a beam whose RSRP of the reference signal is greater than a preset threshold; for another example, the target receiving beam may be a beam whose RSRP of the reference signal is the largest; for another example, the target receiving beam may be a beam whose RSRP of the reference signal is greater than the largest RSRP among multiple beams within the preset threshold.

In high-frequency scenarios, since there is no link between the first terminal device and the second terminal device and the transmit and receive beams cannot be determined, the first terminal device can first send a reference signal to the second terminal device for the second terminal device to train a target receive beam, that is, first determine the receiving direction of the multicast data, and then use the target receive beam to receive the multicast data, thereby realizing multicast transmission.

Therefore, the communication method of the embodiment of the present application sends a reference signal indicating that the data transmission is multicast transmission in multiple first time units by the first terminal device, so that the second terminal device receives the reference signal, and determines the target receiving beam based on the measurement result of the reference signal, thereby using the target receiving beam to receive the multicast data from the first terminal device in at least one second time unit. In this way, it is conducive to realizing multicast transmission at high frequency, and further can improve the data transmission efficiency and save signaling overhead.

In an embodiment of the present application, the multicast group of this multicast transmission may include one or more second terminal devices. Figure 9 only illustrates the interaction between a first terminal device and a second terminal device as an example. For other second terminal devices, the operations performed are similar and will not be repeated here.

In the present application, the time unit may be a millisecond, a subframe, a time slot, a time window or a symbol, which is not limited in the embodiments of the present application.

It should be understood that the reference signal is used to indicate that the current data transmission is multicast transmission, and it can also be understood that the reference signal is used to indicate that the data transmitted in at least one second time unit is multicast data.

Before the above S902, the first terminal device can determine the source identifier of the first terminal device and the group identifier of this multicast transmission, and the multicast group of this multicast transmission includes at least one of the above second terminal devices. The first terminal device can carry the group identifier in the multicast data sent, and the second terminal device can determine whether the group identifier received from the first terminal device matches the group identifier indicated by the second terminal device's own high-level device. If they match, it is determined that it belongs to the multicast group, thereby obtaining the above multicast data.

In one possible implementation, the first terminal device may determine the source identifier of the first terminal device and the group identifier of this multicast transmission according to the information indicated by the high-level layer. In another possible implementation, the first terminal device may determine the source identifier of the first terminal device and the group identifier of this multicast transmission according to the type of service data to be sent.

Optionally, the above-mentioned multiple first time units are predefined, configured, or preconfigured time units, which is not limited in the embodiment of the present application.

Optionally, the at least one second time unit is a predefined, configured, or preconfigured time unit, which is not limited in the embodiment of the present application.

It should be understood that the above-mentioned pre-definition can be understood as a standard definition, which does not require other equipment configuration (and the network equipment or other terminal equipment cannot be changed), and is information recorded/written in advance in the hardware and/or software of the terminal equipment itself. The above-mentioned configuration can be understood as network equipment configuration and terminal equipment configuration. If it is a network equipment configuration, it can be changed through SIB or RRC signaling; if it is a terminal equipment configuration, it can be changed according to PC5-RRC signaling. The above-mentioned pre-configuration can be understood as information recorded/written in advance in the hardware and/or software of the terminal equipment itself, which is determined by the manufacturer of the equipment and can be changed through software or hardware.

It should also be understood that there may be a corresponding relationship between the at least one second time unit and the multiple first time units, and the second terminal device receives the reference signal on the multiple first time units, and can determine which time unit (i.e., at least one second time unit) to receive the multicast data on according to the corresponding relationship. The corresponding relationship may be predefined, configured, or preconfigured, and the embodiments of the present application do not limit this.

Optionally, the reference signal may include a channel state information reference signal CSI-RS or a demodulation reference signal DMRS, or may be other types of reference signals, which is not limited in the embodiments of the present application.

As an optional embodiment, the above-mentioned multiple first time units and the above-mentioned at least one second time unit belong to the same physical layer sidelink feedback channel PSFCH period.

In this way, it is convenient for the first terminal device and the second terminal device to determine the multicast transmission time, and use the same PSFCH period as the data sending period to quickly complete beam scanning and data transmission within the period.

As an optional embodiment, the above-mentioned multiple first time units are the first or first two time units of the PSFCH cycle.

Since the second terminal device needs to complete the beam scanning first, it is necessary to uniformly determine the position of at least the first time unit, and at least the first time unit needs to be at the beginning of the PSFCH period.

As an optional embodiment, the method further includes: the first terminal device sends sideline control information SCI in the third time unit, the SCI carrying information for indicating the at least one second time unit. Correspondingly, the second terminal device receives the SCI in the third time unit.

It should be understood that the SCI carries information for indicating at least one second time unit, and the third time unit for sending the SCI is before the at least one second time unit. The third time unit may be a time unit in the above-mentioned multiple first time units, or may be a time unit different from the above-mentioned multiple first time units, which is not limited in the embodiments of the present application. Exemplarily, the third time unit may be the first time unit of the PSFCH cycle.

As an optional embodiment, after S902, the method further includes: the second terminal device sends feedback information to the first terminal device, the feedback information is used to indicate whether the second terminal device successfully receives the multicast data. Correspondingly, the first terminal device receives feedback information from at least one second terminal device.

Optionally, the feedback information may include ACK information and NACK information, wherein the ACK information is used to indicate that the multicast data is successfully received, and the NACK information is used to indicate that the multicast data is not successfully received. Exemplarily, the second terminal device receives the multicast data of the first terminal device. If the PSSCH is correctly decoded, the second terminal device determines that the multicast data is successfully received, and sends a PSFCH sequence carrying ACK information to the first terminal device; if the PSSCH is not correctly decoded, the second terminal device determines that the multicast data is not successfully received, and sends a PSFCH sequence carrying NACK information to the first terminal device.

For the first terminal device, all second terminal devices in the multicast group feedback that the multicast data is successfully received (for example, all second terminal devices in the multicast group feedback ACK information), the first terminal device considers that the multicast data transmission is successful. Otherwise, the first terminal The device will retransmit the multicast data, thus improving the reliability of multicast data transmission.

It should be understood that the second terminal device can use the beam direction corresponding to the above-mentioned target receiving beam to send the above-mentioned feedback information, and the first terminal device can use the beam direction corresponding to the sending beam of the above-mentioned multicast data to receive the feedback information, but the embodiment of the present application is not limited to this.

The following takes the first terminal device as UE 1 and the second terminal device as UE 2 as an example, and explains it in conjunction with Figure 10.

FIG10 shows a schematic diagram of multicast transmission by UE 1 and UE 2. Among them, T1-T4 belongs to a PSFCH cycle, which corresponds to the PSFCH feedback resource in T6, and T5 and T6 belong to the next PSFCH cycle. T1-T6 can be understood as 6 time slots. UE 1 sends SL CSI-RS at a specific frequency domain position within a specific 4 symbols in T1. UE 2 performs receiving beam scanning at the corresponding position in T1. FIG10 shows the 4 receiving beams of UE 2. UE 2 can try to receive SL CSI-RS with different receiving beams on each of the 4 symbols, thereby obtaining the measurement results of each of the 4 receiving beams, and then selecting the target receiving beam according to the measurement results. Then, UE 1 can send multicast data at T2 within the PSFCH cycle in FIG10. UE 2 receives the multicast data sent by UE 1 at T2 using the target receiving beam determined by T1 within the PSFCH cycle. UE 2 receives the multicast data sent by UE 1. If the PSSCH is decoded correctly, UE 2 can send a PSFCH sequence carrying ACK information to UE 1 at T6. If the PSSCH is not decoded correctly, UE 2 can send a PSFCH sequence carrying NACK information to UE 1 at T6.

It should be understood that FIG. 10 is only an example. In other possible implementations, multicast data may also be transmitted in other time slots (e.g., T3), which is not limited in the embodiments of the present application. In addition, the number of symbols used to send the reference signal may be 4, 6, 8 or other values. For example, UE 1 may use 4 symbols in each of the first 2 time slots to send a reference signal, or UE 1 may use 4 or 6 symbols in the first time slot to send a reference signal, which is not limited in the embodiments of the present application.

In the communication method of the embodiment of the present application, UE 1 can send a reference signal on T1 to indicate that this data transmission is a multicast transmission, and send multicast data on T2. UE 2 can receive the reference signal on T1, and based on the measurement result of the reference signal, determine the target receiving beam for receiving the multicast data, and use the target receiving beam to receive the multicast data on T2. This method enables UE 2 to determine the existence of multicast transmission based on the reference signal sent by UE 1, and determine the beam direction for receiving the multicast data, as well as the time for receiving the multicast data, thereby realizing multicast transmission at high frequency, and further can improve data transmission efficiency and save signaling overhead.

Fig. 11 shows another communication method 1100 provided in an embodiment of the present application. The method 1100 can be applied to the communication system 100 shown in Fig. 1, and can also be applied to other communication systems, which is not limited in the embodiment of the present application.

S1101, a first terminal device determines a target transmission beam based on multiple transmission beams, where a direction of the target transmission beam covers directions of multiple transmission beams, and each of the multiple transmission beams is a transmission beam of the first terminal device between the first terminal device and each of the multiple second terminal devices.

S1102: A first terminal device sends multicast data in at least one first time unit using a target transmission beam. Correspondingly, a second terminal device receives multicast data in at least one first time unit using a target reception beam.

The above-mentioned "coverage" can be understood as: the half-power main lobe width of each of the multiple transmit beams is within the half-power main lobe width of the target transmit beam, or the angle between the maximum radiation direction of the target transmit beam and each of the multiple transmit beams is less than the threshold.

It should be understood that, for a certain second terminal device, the transmission beam and the target reception beam between the first terminal device and the second terminal device are obtained by beam training performed by the first terminal device and the second terminal device when the link is established.

In the present application, the time unit may be a millisecond, a subframe, a time slot, a time window or a symbol, which is not limited in the embodiments of the present application.

Exemplarily, taking UE as an example, as shown in FIG12 , the first terminal device is UE 1, and the multiple second terminal devices are UE 2 and UE 3. In FIG12 (a), UE 1 establishes unicast links with UE 2 and UE 3 respectively, and can perform unicast transmission, wherein beam 1 is a transmission beam for unicast transmission between UE 1 and UE 2, and beam 2 is a transmission beam for unicast transmission between UE 1 and UE 3. In order to ensure that UE 2 and UE 3 can successfully receive multicast data during multicast transmission, UE 1 can use beam a shown in FIG12 (b) to send multicast data. Beam a can be understood as the above-mentioned target transmission beam, and the direction of beam a can cover the direction of beam 1 and beam 2. Therefore, UE 1 can use beam a to send multicast data for multicast transmission, and UE 2 and UE 3 can both receive multicast data.

In the communication method of the embodiment of the present application, the first terminal device can determine the target transmission beam based on multiple transmission beams in unicast transmission, and use the target transmission beam to send multicast data to multiple second terminal devices in at least one first time unit. Multiple second terminal devices determine the target receiving beam, and use the target receiving beam to receive multicast data in at least one first time unit. In this way, an association relationship between unicast and multicast transmission can be established, so that the first terminal device and multiple second terminal devices can complete multicast transmission through the established unicast transmission, and further improve data transmission efficiency and save signaling overhead.

In the embodiment of the present application, a link has been established between the first terminal device and the plurality of second terminal devices, that is, a unicast link has been established, and the first terminal device The first terminal device and each of the multiple second terminal devices know each other's source identifier and destination identifier of the link. When the first terminal device performs multicast transmission, it can first determine the group identifier of this multicast transmission, and the multicast group of this multicast transmission includes the above-mentioned multiple second terminal devices. The first terminal device can carry the group identifier in the multicast data sent, and the second terminal device can determine whether the group identifier received from the first terminal device matches the group identifier indicated by the second terminal device's own high-level device. If they match, it determines that it belongs to the multicast group, thereby obtaining the above-mentioned multicast data.

In one possible implementation, the first terminal device may determine the group identifier of this multicast transmission based on information indicated by a high-level layer. In another possible implementation, the first terminal device may determine the group identifier of this multicast transmission based on a source identifier of the first terminal device. In yet another possible implementation, the first terminal device may determine the group identifier of this multicast transmission based on destination identifiers of different second terminal devices. In yet another possible implementation, the first terminal device may determine the group identifier of this multicast transmission based on the type of service data to be sent.

It should be understood that the above-mentioned at least one first time unit belongs to the same physical layer sidelink feedback channel PSFCH period.

In this way, it can be ensured that the feedback from multiple second terminal devices is on the same PSFCH symbol, and the first terminal device can receive feedback from multiple second terminal devices at the same time.

It should be understood that the at least one first time unit mentioned above is a predefined, configured, or preconfigured time unit, and the embodiments of the present application are not limited to this.

For explanations about predefinition, configuration or pre-configuration, please refer to the relevant description in the above method 900, which will not be repeated here.

As an optional embodiment, the method further includes: the first terminal device sends side control information SCI to multiple second terminal devices respectively, wherein the SCI carries information indicating the at least one first time unit. Correspondingly, the multiple second terminal devices receive the SCI from the first terminal device.

That is, the first terminal device can indicate the time information of the multicast transmission to each second terminal device through the unicast link. For example, the first terminal device can instruct the second terminal device to receive multicast data in a certain time slot or a certain period of time (that is, the above-mentioned at least one time unit). In one possible manner, the first terminal device does not distinguish between unicast transmission and multicast transmission when indicating the above-mentioned at least one time unit, and only indicates that the second terminal device needs to receive in the at least one time unit.

Optionally, when the first terminal device indicates resources to the second terminal device, it needs to ensure that the same beam direction is used within a PSFCH cycle, and ensure that the feedback from all second terminal devices can be received with the same beam on the PSFCH symbol. Otherwise, when receiving PSFCH feedback, the first terminal device will cause a conflict because it cannot use multiple beams simultaneously within one cycle, which will lead to PSFCH reception failure.

As an optional embodiment, after S1102, the method further includes: the second terminal device sends feedback information to the first terminal device, the feedback information being used to indicate whether the second terminal device successfully receives the multicast data. Correspondingly, the first terminal receives feedback information from at least one of the plurality of second terminal devices.

For explanation of the feedback information, please refer to the relevant description in the above method 900, which will not be repeated here.

The following takes the first terminal device as UE 1 and the second terminal devices including UE 2 and UE 3 as an example, and explains in conjunction with Figure 13.

Figure 13 shows a schematic diagram of multicast transmission by UE 1, UE 2 and UE 3. Among them, T1-T4 belongs to a PSFCH cycle, which corresponds to the PSFCH feedback resource in T6, and T5 and T6 belong to the next PSFCH cycle. T1-T6 can be understood as 6 time slots.

UE 1 sends multicast data using the target transmit beam at time slot T2. UE 2 and UE 3 receive multicast data using their respective target receive beams at T2. For UE 2, if PSSCH is correctly decoded, UE 2 can send a PSFCH sequence carrying ACK information to UE 1 at T6; if PSSCH is not correctly decoded, UE 2 can send a PSFCH sequence carrying NACK information to UE 1 at T6. The feedback information of UE 3 is similar to that of UE 2.

It should be understood that FIG. 13 is merely an example, and in other possible implementations, multicast data may also be transmitted in other time slots (eg, T3 or T4), which is not limited in the embodiments of the present application.

In the communication method of the embodiment of the present application, UE 1 and UE 2 and UE 3 establish a unicast link. UE 1 can determine the target transmission beam based on multiple transmission beams when performing unicast transmission with UE 2 and UE 3, and use the target transmission beam to send multicast data to UE 2 and UE 3 at T2. UE 2 and UE 3 determine the target receiving beam, and use the target receiving beam to receive multicast data at T2. In the present application, an association relationship between unicast and multicast transmission can be established, so that UE 1 and UE 2 and UE 3 can complete multicast transmission through the established unicast transmission, and further improve data transmission efficiency and save signaling overhead.

It should be understood that the order of execution of the above processes does not necessarily mean the order in which they are executed. It is logically determined and should not constitute any limitation on the implementation process of the embodiments of the present application.

The communication method according to an embodiment of the present application is described in detail above in combination with Figures 1 to 13. The communication device according to an embodiment of the present application will be described in detail below in combination with Figures 14 and 15.

FIG14 shows a communication device 1400 provided in an embodiment of the present application. The device 1400 includes: a transceiver unit 1410 and a processing unit 1420 .

In a possible implementation, the device 1400 is used to execute the steps/processes corresponding to the first terminal device in the above method 900.

Among them, the transceiver unit 1410 is used to: send a reference signal on multiple first time units, and the reference signal is used to indicate that the data transmission is a multicast transmission; send multicast data on at least one second time unit, and the at least one second time unit is after the multiple first time units.

Optionally, the multiple first time units and the at least one second time unit belong to the same physical layer sidelink feedback channel PSFCH period.

Optionally, the plurality of first time units are predefined, or configured, or preconfigured time units.

Optionally, the multiple first time units are the first or first two time units of the PSFCH cycle.

Optionally, the at least one second time unit is a predefined, or configured, or preconfigured time unit.

Optionally, the transceiver unit 1410 is further used to: send side control information SCI in a third time unit, where the SCI carries information used to indicate the at least one second time unit.

Optionally, the transceiver unit 1410 is further used to: receive feedback information from at least one terminal device, where the feedback information is used to indicate whether the at least one terminal device successfully receives the multicast data.

Optionally, the reference signal includes a channel state information reference signal CSI-RS or a demodulation reference signal DMRS.

In another possible implementation, the device 1400 is used to execute the steps/processes corresponding to the second terminal device in the above method 900.

Among them, the transceiver unit 1410 is used to: receive a reference signal on multiple first time units, and the reference signal is used to indicate that the data transmission is a multicast transmission; the processing unit 1420 is used to: receive multicast data on at least one second time unit based on the measurement result of the reference signal.

Optionally, the multiple first time units and the at least one second time unit belong to the same physical layer sidelink feedback channel PSFCH period.

Optionally, the plurality of first time units are predefined, or configured, or preconfigured time units.

Optionally, the multiple first time units are the first or first two time units in a PSFCH cycle.

Optionally, the at least one second time unit is a predefined, or configured, or preconfigured time unit.

Optionally, the transceiver unit 1410 is further used to: receive sideline control information SCI in a third time unit, where the SCI carries information indicating the at least one second time unit.

Optionally, the processing unit 1420 is also used to: determine the target receiving beam based on the measurement results of the reference signal corresponding to each receiving beam in the multiple receiving beams; the transceiver unit 1410 is also used to: use the target receiving beam to receive multicast data in at least one second time unit.

Optionally, the transceiver unit 1410 is further used to: send feedback information, where the feedback information is used to indicate whether the multicast data is successfully received.

Optionally, the reference signal includes a channel state information reference signal CSI-RS resource.

In another possible implementation, the device 1400 is used to execute the steps/processes corresponding to the first terminal device in the above method 1100.

Among them, the processing unit 1420 is used to: determine the target transmission beam based on multiple transmission beams, the direction of the target transmission beam covers the directions of the multiple transmission beams, and each transmission beam in the multiple transmission beams is a transmission beam of the first terminal device between the first terminal device and each second terminal device in a plurality of second terminal devices; the transceiver unit 1410 is used to: use the target transmission beam to send multicast data to the multiple second terminal devices in at least one first time unit.

Optionally, the at least one first time unit belongs to the same physical layer sidelink feedback channel PSFCH period.

Optionally, the at least one first time unit is a predefined, or configured, or preconfigured time unit.

Optionally, the transceiver unit 1410 is further used to: send side control information SCI to the multiple second terminal devices respectively, and the SCI carries information used to indicate the at least one first time unit.

Optionally, the transceiver unit 1410 is further used to: receive feedback information from at least one second terminal device among the multiple second terminal devices, where the feedback information is used to indicate whether the at least one second terminal device successfully receives the multicast data.

It should be understood that the device 1400 here is embodied in the form of a functional unit. The term "unit" here may refer to an application specific integrated circuit (ASIC), an electronic circuit, a processor (such as a shared processor, a dedicated processor or a group processor, etc.) and a memory for executing one or more software or firmware programs, a combined logic circuit and/or other suitable components that support the described functions. In an optional example, those skilled in the art can understand that the device 1400 can be specifically the first terminal device or the second terminal device in the above-mentioned embodiment, and the device 1400 can be used to execute the various processes and/or steps corresponding to the first terminal device or the second terminal device in the above-mentioned method embodiment. To avoid repetition, it will not be repeated here.

The apparatus 1400 of each of the above schemes has the function of implementing the corresponding steps performed by the first terminal device or the second terminal device in the above method; the function can be implemented by hardware, or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions. For example, the transceiver unit can be replaced by a receiver and a transmitter, and other units, such as a processing unit, can be replaced by a processor, respectively performing the transceiver operations and related processing operations in each method embodiment.

In the embodiment of the present application, the device 1400 in FIG. 14 may also be a chip or a chip system, such as a system on chip (SoC). Correspondingly, the transceiver unit 1410 may be a transceiver circuit of the chip, which is not limited here.

FIG15 shows another communication device 1500 provided in an embodiment of the present application. The device 1500 includes a processor 1510, a transceiver 1520, and a memory 1530. The processor 1510, the transceiver 1520, and the memory 1530 communicate with each other through an internal connection path, the memory 1530 is used to store instructions, and the processor 1510 is used to execute the instructions stored in the memory 1530 to control the transceiver 1520 to send signals and/or receive signals.

It should be understood that the device 1500 can be specifically the first terminal device or the second terminal device in the above embodiment, and can be used to execute the various steps and/or processes corresponding to the first terminal device or the second terminal device in the above method embodiment. Optionally, the memory 1530 may include a read-only memory and a random access memory, and provide instructions and data to the processor. A part of the memory may also include a non-volatile random access memory. For example, the memory may also store information about the device type. The processor 1510 may be used to execute instructions stored in the memory, and when the processor 1510 executes instructions stored in the memory, the processor 1510 is used to execute the various steps and/or processes of the above method embodiment corresponding to the first terminal device or the second terminal device. The transceiver 1520 may include a transmitter and a receiver, the transmitter may be used to implement the various steps and/or processes corresponding to the above transceiver for performing the sending action, and the receiver may be used to implement the various steps and/or processes corresponding to the above transceiver for performing the receiving action.

It should be understood that in the embodiments of the present application, the processor of the above-mentioned device may be a central processing unit (CPU), and the processor may also be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

In the implementation process, each step of the above method can be completed by an integrated logic circuit of hardware in a processor or an instruction in the form of software. The steps of the method disclosed in conjunction with the embodiment of the present application can be directly embodied as a hardware processor for execution, or a combination of hardware and software units in a processor for execution. The software unit can be located in a storage medium mature in the art such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, etc. The storage medium is located in a memory, and the processor executes the instructions in the memory, and completes the steps of the above method in conjunction with its hardware. To avoid repetition, it is not described in detail here.

The present application also provides a computer-readable storage medium, which is used to store a computer program, and the computer program is used to implement the method corresponding to the first terminal device or the second terminal device in the above embodiment.

The present application also provides a computer program product, which includes a computer program (also referred to as code or instruction). When the computer program runs on a computer, the computer can execute the method corresponding to the first terminal device or the second terminal device shown in the above embodiment.

Those of ordinary skill in the art will appreciate that the various method steps and units described in the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the steps and components of each embodiment have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Those of ordinary skill in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only illustrative, for example, the division of the units is only a logical function. In actual implementation, there may be other divisions, for example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not performed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection through some interface, device or unit, or may be an electrical, mechanical or other form of connection.

The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the embodiments of the present application.

In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), disk or optical disk and other media that can store program code.

The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims (26)

A communication method, characterized by comprising: Sending a reference signal over a plurality of first time units, where the reference signal is used to indicate that the current data transmission is a multicast transmission; The multicast data is sent in at least one second time unit, the at least one second time unit being after the plurality of first time units. The method according to claim 1 is characterized in that the multiple first time units and the at least one second time unit belong to the same physical layer sidelink feedback channel PSFCH period. The method according to claim 1 or 2 is characterized in that the multiple first time units are predefined, configured, or preconfigured time units. The method according to any one of claims 1 to 3 is characterized in that the multiple first time units are the first or first two time units of the PSFCH cycle. The method according to any one of claims 1 to 4, characterized in that the at least one second time unit is a predefined, or configured, or preconfigured time unit. The method according to any one of claims 1 to 4, characterized in that the method further comprises: The sideline control information SCI is sent in the third time unit, wherein the SCI carries information for indicating the at least one second time unit. The method according to any one of claims 1 to 6, characterized in that the method further comprises: Feedback information is received from at least one terminal device, where the feedback information is used to indicate whether the at least one terminal device successfully receives the multicast data. The method according to any one of claims 1 to 7 is characterized in that the reference signal includes a channel state information reference signal CSI-RS or a demodulation reference signal DMRS. A communication method, characterized by comprising: receiving a reference signal at a plurality of first time units, wherein the reference signal is used to indicate that the current data transmission is a multicast transmission; Based on the measurement result of the reference signal, multicast data is received in at least one second time unit. The method according to claim 9 is characterized in that the multiple first time units and the at least one second time unit belong to the same physical layer sidelink feedback channel PSFCH period. The method according to claim 9 or 10 is characterized in that the multiple first time units are predefined, configured, or preconfigured time units. The method according to any one of claims 9 to 11 is characterized in that the multiple first time units are the first or first two time units in a PSFCH period. The method according to any one of claims 9 to 12, characterized in that the at least one second time unit is a predefined, or configured, or preconfigured time unit. The method according to any one of claims 9 to 12, characterized in that the method further comprises: Sideline control information SCI is received in a third time unit, wherein the SCI carries information indicating the at least one second time unit. The method according to any one of claims 9 to 14, characterized in that the receiving of multicast data in at least one second time unit based on the measurement result of the reference signal comprises: Determine a target receiving beam based on a measurement result of a reference signal corresponding to each receiving beam in the plurality of receiving beams; The multicast data is received in at least one second time unit using the target receive beam. The method according to any one of claims 9 to 15, characterized in that the method further comprises: Send feedback information, where the feedback information is used to indicate whether the multicast data is successfully received. The method according to any one of claims 9 to 16, characterized in that the reference signal includes a channel state information reference signal CSI-RS resource. A communication method, characterized by comprising: Based on the multiple transmission beams, determine a target transmission beam, where the direction of the target transmission beam covers the directions of the multiple transmission beams, and each transmission beam in the multiple transmission beams is a transmission beam of the first terminal device between the first terminal device and each second terminal device in the multiple second terminal devices; The target transmission beam is used to transmit multicast data to the plurality of second terminal devices in at least one first time unit. The method according to claim 18 is characterized in that the at least one first time unit belongs to the same physical layer sidelink feedback channel PSFCH period. The method according to claim 18 or 19 is characterized in that the at least one first time unit is a predefined, or configured, or preconfigured time unit. The method according to claim 18 or 19, characterized in that the method further comprises: Sideline control information SCI is sent to each of the plurality of second terminal devices, wherein the SCI carries information for indicating the at least one first time unit. The method according to any one of claims 18 to 21, characterized in that the method further comprises: Feedback information is received from at least one second terminal device among the multiple second terminal devices, where the feedback information is used to indicate whether the at least one second terminal device successfully receives the multicast data. A communication device, characterized by comprising: a unit for implementing the method according to any one of claims 1 to 22. A communication device, characterized in that it comprises: a processor, the processor is coupled to a memory, the memory is used to store a computer program, when the processor calls the computer program, the device executes the method according to any one of claims 1 to 22. A computer-readable storage medium, characterized in that it is used to store a computer program, wherein the computer program includes instructions for implementing the method as described in any one of claims 1 to 22. A computer program product, comprising instructions, wherein when the instructions are executed on a computer, the computer is enabled to implement the method according to any one of claims 1 to 22.