Data transmission method and apparatus

Abstract

The present application provides a data transmission method and device for solving the problem of high multicast transmission control signaling overhead. The method includes the steps of receiving first multicast data utilizing multicast-based semi-persistent scheduling SPS transmission, receiving first downlink control information DCI, where the first DCI is scrambled by a configured scheduling radio network temporary identifier CS-RNTI, and receiving first data based on the first DCI, where the first data is a retransmission data of the first multicast data.

Description

Technical Field

[0001] Cross-reference to Related Applications This application claims priority to Chinese Patent Application No. 202110364242.9, titled "DATA TRANSMISSION METHOD AND APPARATUS", filed with the China National Intellectual Property Administration on April 4, 2021, the entire content of which is incorporated herein by reference.

[0002] Embodiments of this application relate to the field of communication technologies, and more particularly, to data transmission methods and apparatuses.

Background Art

[0003] In a 4th generation (4G) network or a 5th generation (5G) network, a base station can transmit data to a terminal in a multicast mode or a unicast mode. Compared with the unicast mode, the multicast mode can save downlink resources. 5G ) network, a base station can transmit data to a terminal in a multicast mode or a unicast mode. Compared with the unicast mode, the multicast mode can save downlink resources.

[0004] Currently, dynamic scheduling is usually used for transmission in the multicast mode. For example, every time before a physical downlink shared channel (PDSCH) is transmitted, a physical downlink control channel (PDCCH) needs to be transmitted to schedule the PDSCH, and the PDSCH carries downlink data. In this mode, the control signaling overhead is high, resulting in low data transmission efficiency.

Summary of the Invention

[0005] Embodiments of this application provide a data transmission method and apparatus for reducing signaling overhead and improving data transmission efficiency.

[0006] According to a first aspect, an embodiment of the present application provides a data transmission method comprising: receiving first multicast data utilizing multicast-based semi-persistent scheduling SPS transmission; receiving first downlink control information DCI, wherein the first DCI is scrambled by a configuration scheduling radio network temporary identifier CS-RNTI; and receiving first data based on the first DCI, wherein the first data is retransmitted data of the first multicast data.

[0007] In this embodiment of the present application, multicast data is transmitted through semi-persistent scheduling without the need to transmit scheduling information, i.e., DCI, each time multicast data is sent, thereby reducing control signaling overhead. In addition, if data needs to be retransmitted to individual terminal devices, the multicast data is retransmitted to the terminal devices in unicast mode instead of scheduling data retransmission in multicast mode. In this way, the occupation of downlink resources can be further reduced and data transmission efficiency can be improved.

[0008] In an optional implementation, the method further includes the step of receiving a second DCI scrambled by a group configuration scheduling radio network temporary identifier G-CS-RNTI, the second DCI being used to activate multicast-based semi-persistent scheduling SPS transmission.

[0009] In an optional implementation, the method further includes the step of receiving a third DCI scrambled by a group radio network temporary identifier G-RNTI, the third DCI being used to activate multicast-based semi-persistent scheduling SPS transmission, the value of a first indication information contained in the third DCI being a first value, the value of the first indication information containing a first value or a second value, the first value indicating multicast-based semi-persistent scheduling SPS transmission, and the second value indicating multicast-based dynamic scheduling transmission. A scheme indicating semi-persistent or dynamic scheduling is defined in the DCI, thereby enabling the use of G-RNTI to dynamically schedule multicast data or to semi-persistently schedule multicast data. This extends the application scenarios of G-RNTI, saves blind detection resources on the terminal device side, and reduces control signaling overhead when scheduling multicast downlink data.

[0010] In an optional implementation, the third DCI does not include information indicating that the third DCI is used to schedule uplink or downlink transmissions.

[0011] In an optional implementation, the new data indicator NDI value in the first DCI is 1, the new data indicator NDI value in the second DCI is 0, and the new data indicator NDI value in the third DCI is 0. The NDI in the DCI can be used to distinguish whether the scheduled data is the data to be transmitted initially or the data to be retransmitted.

[0012] In an optional implementation, the method further includes the steps of receiving a fourth DCI scrambled by a group radio network temporary identifier G-RNTI, the fourth DCI being used to deactivate multicast-based semi-persistent scheduling SPS transmissions, or receiving a fourth DCI scrambled by a group configuration scheduling radio network temporary identifier G-CS-RNTI, the fourth DCI being used to deactivate multicast-based semi-persistent scheduling SPS transmissions. It can be understood that the G-RNTI corresponding to the fourth DCI may be the same as or different from the G-RNTI corresponding to the third DCI. Similarly, the G-CS-RNTI corresponding to the fourth DCI may be the same as or different from the G-CS-RNTI corresponding to the second DCI.

[0013] According to a second aspect, embodiments of the present application provide a data transmission method which can be applied to a network device and includes the steps of: transmitting first multicast data utilizing multicast-based semi-persistent scheduling SPS transmission, the first multicast data which can typically be understood to be transmitted to a plurality of terminal devices; and transmitting first downlink control information DCI to a single terminal device among the plurality of terminal devices, the first DCI being scrambled by a configuration scheduling radio network temporary identifier CS-RNTI, the first DCI being used to schedule first data, the first data being retransmission data of the first multicast data. The single terminal device is one of one or more terminal devices which has not successfully received the first multicast data, or the single terminal device is one of one or more terminal devices which has not received positive feedback for the first multicast data from a network-side device, or the single terminal device is one of one or more terminal devices which has received negative feedback for the first multicast data from a network-side device.

[0014] In this embodiment of the present application, multicast data is transmitted through semi-persistent scheduling without the need to transmit scheduling information, i.e., DCI, each time multicast data is transmitted, thereby reducing control signaling overhead. In addition, when data needs to be retransmitted to individual terminal devices, the multicast data is retransmitted to the terminal devices in unicast mode instead of scheduling data retransmission in multicast mode. In this way, the occupation of downlink resources can be further reduced and data transmission efficiency can be improved.

[0015] In an optional implementation, the method further includes the step of transmitting a second DCI scrambled by a group configuration scheduling radio network temporary identifier G-CS-RNTI, the second DCI being used to activate multicast-based semi-persistent scheduling SPS transmission.

[0016] In an optional implementation, the method further includes the step of transmitting a third DCI scrambled by a group radio network temporary identifier G-RNTI, the third DCI being used to activate multicast-based semi-persistent scheduling SPS transmission, the value of a first indication information contained in the third DCI being a first value, the value of the first indication information being a first value or a second value, the first value indicating multicast-based semi-persistent scheduling SPS transmission, and the second value indicating multicast-based dynamic scheduling transmission. A scheme indicating semi-persistent or dynamic scheduling is defined in the DCI, thereby enabling the use of G-RNTI to dynamically schedule multicast data or to semi-persistently schedule multicast data. This extends the application scenarios of G-RNTI, saves blind detection resources on the terminal device side, and reduces control signaling overhead when scheduling multicast downlink data.

[0017] In an optional implementation, the third DCI does not include information indicating that the third DCI is used to schedule uplink or downlink transmissions.

[0018] In an optional implementation, the new data indicator NDI value in the first DCI is 1, the new data indicator NDI value in the second DCI is 0, and the new data indicator NDI value in the third DCI is 0. The NDI in the DCI can be used to distinguish whether the scheduled data is the data to be transmitted initially or the data to be retransmitted.

[0019] In an optional implementation, the method further includes the steps of: transmitting a fourth DCI scrambled by a group radio network temporary identifier G-RNTI, the fourth DCI being used to deactivate multicast-based semi-persistent scheduling SPS transmissions; or transmitting a fourth DCI scrambled by a group configuration scheduling radio network temporary identifier G-CS-RNTI, the fourth DCI being used to deactivate multicast-based semi-persistent scheduling SPS transmissions.

[0020] According to a third aspect, an embodiment of the present application provides a data transmission apparatus comprising: a communication unit configured to receive first multicast data utilizing multicast-based semi-persistent scheduling SPS transmission, the communication unit further configured to receive first downlink control information DCI, the first DCI being scrambled by a configuration scheduling radio network temporary identifier CS-RNTI; and a processing unit configured to receive first data through the communication unit based on the first DCI, the first data being retransmitted data of the first multicast data. Optionally, before the communication unit receives the first DCI, the processing unit is further configured to determine that reception of the first multicast data has failed and to transmit feedback information such as a NACK, the feedback information indicating that reception of the first multicast data has failed.

[0021] In an optional implementation, the communication unit is further configured to receive a second DCI scrambled by the Group Configuration Scheduling Radio Network Temporary Identifier G-CS-RNTI, the second DCI being used to activate multicast-based semi-persistent scheduling SPS transmissions.

[0022] In an optional implementation, the communication unit is further configured to receive a third DCI scrambled by the group radio network temporary identifier G-RNTI, the third DCI being used to activate multicast-based semi-persistent scheduling SPS transmission, the value of the first indication information contained in the third DCI being a first value, the value of the first indication information being a first value or a second value, the first value indicating multicast-based semi-persistent scheduling SPS transmission and the second value indicating multicast-based dynamic scheduling transmission.

[0023] In an optional implementation, the third DCI does not include information indicating that the third DCI is used to schedule uplink or downlink transmissions.

[0024] In the optional implementation, the new data indicator NDI value in the first DCI is 1, the new data indicator NDI value in the second DCI is 0, and the new data indicator NDI value in the third DCI is 0.

[0025] In the implementation of optional communication, unitreceiving a fourth DCI scrambled by a group radio network temporary identifier (G-RNTI), wherein the fourth DCI is used to deactivate a multicast-based semi-persistent scheduling (SPS) transmission, or receiving a fourth DCI scrambled by a group configuration scheduling radio network temporary identifier (G-CS-RNTI), wherein the fourth DCI is used to deactivate a multicast-based semi-persistent scheduling (SPS) transmission, and is further configured to perform the above actions.

[0026] According to a fourth aspect, an embodiment of the present application provides a data transmission device including a processing unit configured to generate first multicast data using a multicast-based semi-persistent scheduling (SPS) transmission, and a communication unit configured to transmit the first multicast data. The communication unit is further configured to transmit a first downlink control information (DCI), where the first DCI is scrambled by a configuration scheduling radio network temporary identifier (CS-RNTI), and the first DCI is used to schedule first data, and the first data is retransmission data of the first multicast data.

[0027] In this embodiment of the present application, semi-persistent scheduling is used for multicast transmission, so that it is not necessary to transmit scheduling information, i.e., DCI, every time before the multicast data is transmitted, thereby reducing the control signaling overhead. In addition, when the data needs to be retransmitted to individual terminal devices, instead of scheduling the data retransmission in the multicast mode, the multicast data is retransmitted to the terminal devices in the unicast mode. In this way, it is possible to further reduce the occupancy of downlink resources and improve the data transmission efficiency.

[0028] In an optional implementation, the communication unit is further configured to transmit a second DCI scrambled by a group configuration scheduling radio network temporary identifier G-CS-RNTI, and the second DCI is used to activate a multicast-based semi-persistent scheduling SPS transmission.

[0029] In an optional implementation, the communication unit is further configured to transmit a third DCI scrambled by a group radio network temporary identifier G-RNTI, the third DCI is used to activate a multicast-based semi-persistent scheduling SPS transmission, the value of the first indication information included in the third DCI is the first value, the value of the first indication information includes the first value or the second value, the first value indicates a multicast-based semi-persistent scheduling SPS transmission, and the second value indicates a multicast-based dynamic scheduling transmission.

[0030] In an optional implementation, the third DCI does not include information indicating that the third DCI is used to schedule uplink transmission or downlink transmission.

[0031] In an optional implementation, the new data indicator NDI value in the first DCI is 1, the new data indicator NDI value in the second DCI is 0, and the new data indicator NDI value in the third DCI is 0.

[0032] In an optional implementation, the communication unit is further configured to transmit a fourth DCI scrambled by the group radio network temporary identifier G-RNTI, the fourth DCI being used to deactivate multicast-based semi-persistent scheduling SPS transmissions, or to transmit a fourth DCI scrambled by the group configuration scheduling radio network temporary identifier G-CS-RNTI, the fourth DCI being used to deactivate multicast-based semi-persistent scheduling SPS transmissions.

[0033] According to a fifth aspect, embodiments of the present application provide a communication device including a processor. The processor is coupled to memory. The memory is configured to store computer programs or instructions. The processor is configured to execute computer programs or instructions to carry out the method according to the implementation of the first or second aspect. The memory may be located inside or outside the device. There may be one or more processors.

[0034] According to a sixth aspect, an embodiment of the present application provides a communication device including a logic circuit and an input / output interface. The input / output interface is configured to input first multicast data utilizing multicast-based semi-persistent scheduling SPS transmission. The input / output interface is further configured to input first downlink control information DCI, the first DCI being scrambled by a configuration scheduling radio network temporary identifier CS-RNTI. The logic circuit is configured to acquire first data through the input / output interface based on the first DCI, the first data being retransmitted data of the first multicast data. Optionally, before the first DCI is input through the input / output interface, the logic circuit is further configured to determine that reception of the first multicast data has failed and to output feedback information such as a NACK, the feedback information indicating that reception of the first multicast data has failed.

[0035] According to a seventh aspect, an embodiment of the present application provides a communication device including a logic circuit and an input / output interface. The logic circuit is configured to generate first multicast data utilizing multicast-based semi-persistent scheduling SPS transmission. The input / output interface is configured to output the first multicast data. The input / output interface is further configured to output first downlink control information DCI, the first DCI being scrambled by a configuration scheduling radio network temporary identifier CS-RNTI, the first DCI being used to schedule first data, the first data being retransmission data of the first multicast data.

[0036] According to the eighth aspect, the present application provides a communication device including a processor and an interface circuit. The interface circuit is configured to communicate with other devices. The processor is used in a manner according to the implementation of the first or second aspect.

[0037] According to the ninth aspect, the present application provides a communication system including a terminal device configured to perform the method according to the implementation of the first aspect and a network device configured to perform the method according to the implementation of the second aspect.

[0038] According to a tenth aspect, the application further provides a chip system including a processor configured to perform a method according to an implementation of the first or second aspect.

[0039] According to the eleventh aspect, the application further provides a computing program product including computer executable instructions. When the computer executable instructions are executed on a computer, the method according to the implementation of the first or second aspect is carried out.

[0040] According to the twelfth aspect, the present application further provides a computer-readable storage medium. The computer-readable storage medium stores a computer program or instruction. When an instruction is executed on a computer, the method according to the implementation of the first or second aspect is carried out.

[0041] For technical effects that can be achieved in the fifth through tenth embodiments, please refer to the descriptions of the technical effects that can be brought about by the corresponding technical solutions in the first and second embodiments. Further details will not be explained again here. [Brief explanation of the drawing]

[0042] [Figure 1] This is a schematic diagram of the architecture of a communication system according to an embodiment of this application. [Figure 2] This is a schematic diagram of data scheduling using multicast-based SPS transmission according to an embodiment of this application. [Figure 3] This is a schematic diagram of a unicast retransmission scheduling mechanism according to an embodiment of the present application. [Figure 4] This is a schematic diagram illustrating the deactivation of multicast-based SPS transmission according to an embodiment of this application. [Figure 5] This is another schematic diagram of data scheduling using multicast-based SPS transmission according to an embodiment of the present application. [Figure 6] This is another schematic diagram illustrating the deactivation of multicast-based SPS transmission according to an embodiment of the present application. [Figure 7] This is a schematic flowchart of the data transmission method according to the embodiment of this application. [Figure 8] This is a schematic diagram of the structure of a data transmission device according to an embodiment of this application. [Figure 9] This is a schematic diagram of the structure of a communication device according to an embodiment of this application. [Figure 10]This is a schematic diagram of the structure of another communication device according to an embodiment of this application. [Modes for carrying out the invention]

[0043] The data transmission methods and apparatus provided in embodiments of this application can be used in various communication systems, particularly in harmonized communication and sensing (HCS) systems. Communication systems include, but are not limited to, long-term evolution (LTE) systems, 5G systems, new radio (NR) systems, wireless fidelity (Wi-Fi) systems, other wireless communication systems associated with the 3rd generation partnership project (3GPP), or wireless communication systems that may emerge in the future.

[0044] In the following, some terms used in the embodiments of this application are described to help those skilled in the art to have a better understanding.

[0045] (1) Network devices

[0046] Network devices can communicate with terminal devices to provide wireless access services for those terminal devices. Network devices may also be called base station devices or base stations. Base stations can take several forms, such as macro base stations, micro base stations, relay stations, and access points. For example, a network device provided below in embodiments of this application may be a base station in NR, and a base station in 5G NR may also be called a transmission reception point (TRP) or next generation NodeB (gNB). A network device provided below in embodiments of this application may, alternatively, be a NodeB (NodeB, NB) in a wideband code division multiple access (WCDMA) system. A network device provided below in embodiments of this application may, alternatively, be an evolved NodeB (eNB or eNodeB) in a long-term evolution (LTE) system.

[0047] In embodiments of this application, the communication device configured to perform the functions of a network device may be a network device, or a network device having some functions of a base station, or a device capable of supporting a network device when performing its functions, such as a chip system. The device may be mounted on a network device.

[0048] (2) Terminal devices

[0049] Terminal devices may also be called user equipment (UE), access terminals, terminal units, terminal stations, mobile stations, remote stations, remote terminals, mobile devices, user terminals, terminals, wireless communication devices, terminal agents, or terminal equipment. For example, terminal devices include handheld devices, in-vehicle devices, wearable devices, or computing devices with wireless communication capabilities, terminal devices in 5G networks, or terminal devices in future advanced PLMN networks. For example, terminal devices may be mobile phones, tablet computers, or computers with wireless receiver capabilities. Alternatively, terminal devices may be virtual reality (VR) terminal devices, augmented reality (AR) terminal devices, wireless terminals in industrial control, wireless terminals in autonomous driving, wireless terminals in telemedicine, wireless terminals in smart grids, or wireless terminals in smart cities such as smart refuelers, terminal devices in high-speed trains, or wireless terminals in smart homes such as smart stereos, smart coffee machines, or smart printers.

[0050] In embodiments of this application, a communication device configured to perform the functions of a terminal device may be a terminal device, or a terminal device having some of the functions of a terminal, or a device capable of supporting a terminal device when performing its functions, such as a chip system. The device may be installed in the terminal device.

[0051] (3) Downlink control channel and downlink data channel

[0052] In the downlink transmission process, signals transmitted by a network device to a terminal device are also called downlink signals, and downlink signals include downlink control signals and downlink data signals. In the embodiments of this application, the downlink control channel is used to represent a downlink control signal. In other words, the downlink control channel can also be understood as a downlink control signal, and the downlink control channel can be a physical downlink control channel (PDCCH). In the embodiments of this application, the downlink data channel is used to represent a downlink data signal. In other words, the downlink data channel can also be understood as a downlink data signal, and the downlink data channel can be a physical downlink shared channel (PDSCH).

[0053] A downlink control channel may be configured to schedule a downlink data channel. For example, a PDCCH may be configured to carry PDSCH-related scheduling and configuration information, the PDSCH may carry downlink data, the PDCCH may carry downlink control information (DCI), the DCI may indicate configuration information of the PDSCH (such as time / frequency location and modulation information), and the DCI may also indicate indication information of time-domain resources occupied by feedback information corresponding to the PDSCH scheduled using the DCI. Based on a hybrid automatic repeat request (HARQ) mechanism, the feedback information may include acknowledgment (ACK) or negative acknowledgment (NACK) information indicating whether the terminal device has successfully received the downlink data. ACK may also be called HARQ-ACK, and NACK may also be called HARQ-NACK. Specifically, after receiving downlink data, the terminal device feeds back ACK information on the uplink control channel (physical uplink control channel, PUCCH) if the reception is correct, or NACK information on the PUCCH if the reception is incorrect.

[0054] In addition, DCI includes fallback DCI and non-fallback DCI. fart They are classified as follows: Fallback DCI is DCI in formats 0_0 and 1_0, and non-fallback DCI is DCI in formats 0_1 / 0_2 and 1_1 / 1_2. DCI in formats 0_0 / 0_1 / 0_2 is used for uplink transmission, and DCI in formats 1_0 / 1_1 / 1_2 is used for downlink transmission.

[0055] (4) Unicast and multicast

[0056] The unicast transmission mode is a one-to-one data transmission mode. In the embodiments of this application, unicast means that a network device transmits a downlink signal, for example, unicast data, to a single terminal device.

[0057] Multicast transmission mode is a one-to-many data transmission mode. In embodiments of this application, multicast means that a network device sends the same downlink signal, for example, multicast data, to a group of terminal devices, and all terminal devices in the group can receive the multicast data. A group of terminal devices includes multiple terminal devices. Optionally, groups of terminal devices may be located in the same cell. In multicast transmission mode, it can be understood that groups of terminal devices may share resources, and that downlink signals transmitted by a network device over those resources may be received by the group of terminal devices. Compared to unicast transmission mode, downlink signal transmission resources can be saved.

[0058] Multicast in embodiments of this application may be understood to include, but is not limited to, multicast and / or broadcast.

[0059] (5) Dynamic scheduling

[0060] Dynamic scheduling means that, before each PDSCH is sent, the network device must send a PDCCH used to schedule the current PDSCH. A PDSCH based on dynamic scheduling can also be called a successfully scheduled PDSCH. A successfully scheduled PDSCH can be understood as a PDSCH that has scheduling information. Dynamic scheduling can be used in multicast or unicast transmission scenarios.

[0061] Optionally, for unicast dynamic scheduling, the network device assigns one cell-radio network temporary identifier (C-RNTI) to one terminal device. Before each PDSCH transmission to multiple terminal devices in unicast mode, the network device transmits a DCI scrambled by each terminal device's C-RNTI. Each terminal device can blind-detect the PDCCH based on its own C-RNTI and receive downlink data. In addition, it should be noted that the C-RNTI identifies unicast dynamic scheduling and may be configured by the network device for a single terminal device. Of course, the C-RNTI may be, alternatively, any other identifier capable of identifying unicast dynamic scheduling. This is not limited to the embodiments of this application.

[0062] Optionally, for multicast dynamic scheduling, the network device assigns the same group-radio network temporary identifier (G-RNTI) to multiple terminal devices. Before each time a PDSCH is sent to multiple terminal devices in multicast mode, the network device sends a DCI scrambled by the G-RNTI. Each terminal device can blindly detect the PDCCH based on the G-RNTI and receive the same PDSCH, and reception can also be understood as receiving the downlink data carried on the PDSCH. In addition, it should be noted that the G-RNTI identifies multicast / broadcast scheduling and can be configured by the network device for a group of terminal devices. Of course, the G-RNTI can be any other identifier, such as an M-RNTI, if any other identifier is capable of identifying multicast / broadcast scheduling. This is not limited to the embodiments of this application.

[0063] (6) Semi-persistent scheduling (SPS)

[0064] Semi-persistent scheduling (SPS) means that a terminal device may periodically receive PDSCHs based on a semi-persistent scheduling configuration indicated by a network device. Semi-persistent scheduling may also be called semi-static scheduling. Before sending a PDSCH to a terminal device for the first time, the network device first sends an activation PDCCH (or activation DCI) to the terminal device. The activation PDCCH is used to activate the corresponding SPS configuration. The activation PDCCH further indicates the downlink time domain resource that will be occupied by the downlink data scheduled by the activation PDCCH. Specifically, the occupied downlink time domain resource may include the downlink slot where the scheduled downlink data is placed, the start symbol S where the downlink data is placed in the downlink slot, and the length L. Subsequently, the terminal device may receive PDSCHs sent by the network device based on the activated SPS configuration. Regarding the semi-persistent scheduling scheme, it can be understood that the first PDSCH transmitted by a network device is scheduled by the activated PDCCH, and subsequent PDSCHs transmitted by the network device do not need to be scheduled by other PDCCHs, but are all based on the activated PDCCH. Alternatively, the first PDSCH transmitted by a network device can be called a PDSCH with scheduling information, and subsequent PDSCHs transmitted by the network device can be understood as PDSCHs without scheduling information.

[0065] A network device may configure one or more SPS configurations for terminal devices, for example, up to eight SPS configurations. The parameters in each SPS configuration may be the same or different. The parameters included in each SPS configuration may include, namely, the index (ID) corresponding to the SPS configuration, the SPS transmission periodicity, configuration information for the physical uplink control channel (PUCCH) resource, and at least one of the following: the modulation and coding scheme table (MCS table), where MCS refers to the modulation and coding scheme, or the information used to determine the hybrid automatic repeat request (HARQ) process.

[0066] The configuration information for a PUCCH resource is used to configure the symbols that occupy a slot by the PUCCH resource that carries the feedback information. The configuration information for a PUCCH resource includes PUCCH format 0 or PUCCH format 1 and indicates that the length of the feedback information that can be accommodated by the PUCCH resource is 1 bit or 2 bits. When a network device configures one SPS configuration for a terminal device, it should be noted that the terminal device can perform feedback based on the PUCCH resources indicated in the SPS configuration. When a network device configures multiple SPS configurations for a terminal device, the terminal device needs to determine which PUCCH resource to use to carry the feedback information from the set of PUCCH resources for the SPS. The aforementioned set of PUCCH resources for the SPS is configured in the PUCCH-config configured by the higher layer.

[0067] The modulation / coding scheme table shows the modulation / coding schemes used by the scheduled PDSCH and can be specifically represented using the MCS index.

[0068] The aforementioned information used to determine the HARQ process includes the number of HARQ processes available for SPS and the offsets that comprise them, and a specific HARQ process ID may be determined in the following manner.

[0069] The HARQ Process ID is [floor(CURRENT_slot × 10 / (numberOfSlotsPerFrame × periodicity))] modulo nrofHARQ-Processes + harq-ProcID-Offset, where, CURRENT_slot = [(SFN × numberOfSlotsPerFrame) + slot number in the frame].

[0070] SFN represents the system frame number, numberOfSlotsPerFrame is the number of slots in each subframe, the slot number in the frame represents the index of the current slot, periodicity is the transmission periodicity, nrofHARQ-Processes is the number of HARQ processes available for SPS, and harq-ProcID-Offset is the configured offset.

[0071] Here, it can be understood that the HARQ process ID identifies the HARQ process used by the terminal device to receive PDSCH, which is based on SPS transmission, after the SPS configuration has been activated.

[0072] Based on semi-persistent scheduling, network devices do not need to transmit a PDCCH used for scheduling each time before transmitting downlink data. Compared to dynamic scheduling schemes, control signaling overhead can be reduced. In related technical solutions, semi-persistent scheduling is used in unicast scenarios. For example, before transmitting downlink data to a single terminal device for the first time, the network device transmits one activation DCI. The terminal device blindly detects the activation DCI on the PDCCH and receives the first downlink data transmitted by the network device based on the downlink time domain resources indicated by the activation DCI. The network device then transmits downlink data and no longer transmits DCIs for scheduling, and the terminal device receives the downlink data based on the activated SPS configuration. However, there is no design for utilizing semi-persistent scheduling in multicast scenarios. Considering that multicast mode can conserve downlink resources and multicast dynamic scheduling increases control signaling overhead, embodiments of this application provide a multicast semi-persistent scheduling implementation solution. This solution is described in detail in the following sections.

[0073] (7) Scrambling

[0074] In embodiments of this application, scrambling means that the CRC check bits corresponding to DCIs being transported on the PDCCH are scrambled using a specific RNTI. For ease of description, a DCI after being scrambled by a specific RNTI is abbreviated as a DCI scrambled by an RNTI. Since DCIs are transported on the PDCCH, a DCI may also be called a PDCCH scrambled by an RNTI, for example, a DCI scrambled by a C-RNTI, or a DCI scrambled by a G-RNTI.

[0075] (8) Blind detection

[0076] In the embodiments of this application, blind detection means that a terminal device attempts to receive possible DCIs by performing blind detection on a PDCCH using a specific RNTI. For ease of description, this may also be referred to as a terminal device performing blind detection on a DCI using a specific RNTI, or a terminal device performing blind detection on a PDCCH on a DCI using a specific RNTI. For example, a terminal device performs blind detection on a PDCCH (DCI) using a C-RNTI.

[0077] (9) In the embodiments of this application, “multiple” refers to two or more. The term “and / or” describes an association relationship for describing related objects, indicating that three relationships may exist. For example, A and / or B may represent the following three cases: A only exists, both A and B exist, and B only exists. The symbol “ / ” generally indicates an “or” relationship between related objects. In addition, terms such as “first” and “second” may be used to describe objects in embodiments of this application, but it should be understood that these objects should not be limited by these terms. These terms are used only to distinguish objects from one another.

[0078] (10) The terms “includes,” “has,” and any variations thereof as used in the description of embodiments of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device comprising a set of steps or units may, at their discretion, further include other steps or units not listed, or other steps or units specific to the process, method, product, or device, without limitation. It should be noted that in embodiments of this application, words such as “example” or “for example” are used to indicate that an example, illustration, or explanation is being given. Any embodiment or design scheme described as “example” or “for example” in embodiments of this application should not be construed as having more advantages than other embodiments or design schemes. Strictly speaking, the use of words such as “example” or “for example” is intended to present the relevant concepts in a specific manner.

[0079] Considering the large control signaling overhead in multicast dynamic scheduling, embodiments of this application provide a data transmission method. A multicast semi-persistent scheduling solution is implemented, which not only saves downlink resources but also reduces control signaling overhead and improves data transmission efficiency.

[0080] Please refer to the communication system shown in Figure 1. The data transmission method provided in the embodiments of this application may be applied to the communication system. The communication system includes at least one terminal device and at least one network device. For example, Figure 1 shows one network device and six terminal devices such as UE1, UE2, UE3, UE4, UE5, and UE6.

[0081] In multicast mode, a network device may indicate to multiple terminal devices that it is activating a semi-persistent scheduling configuration. Alternatively, this can be understood as the network device indicating to multiple terminal devices that it is activating a multicast-based semi-persistent scheduling SPS transmission and sending downlink data that utilizes the multicast-based semi-persistent scheduling transmission in multicast mode to multiple terminal devices. The downlink data may be abbreviated as a group SPS PDSCH. Each terminal device receives the aforementioned group SPS PDSCH that utilizes the multicast-based semi-persistent scheduling transmission and may send feedback information corresponding to the group SPS PDSCH to the network device. The network device may receive feedback information corresponding to the group SPS PDSCH sent by each terminal device, and the feedback information may be an ACK or a NACK. Based on the feedback information sent by each terminal device, the network device determines whether the aforementioned group SPS PDSCH needs to be retransmitted. In addition, the network device may further indicate to multiple terminal devices that it is activating a semi-persistent scheduling configuration in multicast mode. Alternatively, this can be understood as a network device instructing multiple terminal devices to deactivate multicast-based semi-persistent scheduling SPS transmissions.

[0082] The data transmission method provided in the embodiments of this application may be applied to the following communication services: enhanced mobile broadband (eMBB), massive machine-type communications (mmTC), and ultra-reliable and low latency communication (URLLC). For example, the method may be applied to scenarios such as autonomous driving or telemedicine for URLLC services, which can reduce instruction overhead as much as possible while meeting the requirements for high reliability and low latency.

[0083] The data transmission method provided in embodiments of this application may include at least one of the following steps: activating a multicast-based semi-persistent scheduling transmission, deactivating a multicast-based semi-persistent scheduling transmission, and retransmitting data related to the multicast-based semi-persistent scheduling transmission. For example, the data transmission method includes activating a multicast-based semi-persistent scheduling transmission and deactivating a multicast-based semi-persistent scheduling transmission. Another example is the data transmission method including activating a multicast-based semi-persistent scheduling transmission and retransmitting data related to the multicast-based semi-persistent scheduling transmission. Another example is the data transmission method including activating a multicast-based semi-persistent scheduling transmission, retransmitting data related to the multicast-based semi-persistent scheduling transmission, and deactivating a multicast-based semi-persistent scheduling transmission. The above steps will be described in more detail below in relation to Solutions 1 and 2. It should be noted that Solutions 1 and 2 may be implemented in combination with each other or independently of each other.

[0084] In the following methods, the steps of a network device may be performed by different functional entities contained within that network device. In other words, the functional entities that perform the steps of a network device may be located in different physical entities. For example, the transmit or receive actions of a network device may be located in the network device's radio frequency (RF) unit, radio remote unit (RRU), or active antenna unit (AAU). Actions processed by the network device may be located in the network device's central unit (CU), etc. This is not limited to the present application.

[0085] Solution 1:

[0086] A1: Activate multicast-based semi-persistent scheduling transmission.

[0087] A network device may configure the same group-configured scheduling-radio network temporary identifier (G-CS-RNTI) for multiple terminal devices. Before first transmitting the same downlink data (i.e., the aforementioned group SPS PDSCH) to multiple terminal devices, the network device transmits a single DCI scrambled by the G-CS-RNTI. The terminal devices blindly detect the DCI scrambled by the G-CS-RNTI on the PDCCH, activate a multicast-based semi-persistent scheduling SPS transmission based on the DCI scrambled by the G-CS-RNTI, and receive the group SPS PDSCH transmitted by the network device for the first time. It should be noted that the G-CS-RNTI may identify multicast semi-persistent scheduling or multicast-based semi-persistent scheduling retransmissions, and may be configured by the network device for a group of terminal devices. Of course, the G-CS-RNTI may be replaced by other identifiers if those identifiers can identify multicast semi-persistent scheduling or multicast-based semi-persistent scheduling retransmissions. This is not limited to the embodiments of this application.

[0088] Optionally, a DCI used to activate multicast-based semi-persistent scheduled SPS transmissions scrambled by G-CS-RNTI may be abbreviated as an activated DCI. The following describes in detail the contents of a DCI sent by a network device that is scrambled by G-CS-RNTI.

[0089] Optionally, DCIs transmitted by a network device, which are scrambled by G-CS-RNTI, include information identifying that the DCI is an activated DCI. For example, the DCI includes a redundancy version field, which is all zero to identify that the DCI is an activated DCI. In this case, the terminal device receives one DCI based on G-CS-RNTI. If the received DCI includes the information identifying that the DCI is an activated DCI as described above, the terminal device knows that the received DCI is an activated DCI and will be used to activate multicast-based semi-persistent scheduling SPS transmissions.

[0090] Optionally, DCI transmitted by a network device and scrambled by G-CS-RNTI may indicate at least one of the following time parameters: the slot in which the group SPS PDSCH is located, the start symbol S and length L in which the group SPS PDSCH is located, and the slot in which the feedback information corresponding to the group SPS PDSCH is located. For example, DCI may include a bit field indicating the resources occupied in the time domain by the data scheduled by DCI, i.e., a Time domain resource assignment field. The range of values ​​for the number of bits occupied by the Time domain resource assignment field is [0, 4]. Optionally, DCI transmitted by a network device and scrambled by G-CS-RNTI may further include a bit field indicating the resources occupied in the frequency domain by the data scheduled by DCI, i.e., a Frequency domain resource assignment field. Optionally, DCI transmitted by a network device and scrambled by G-CS-RNTI may further include a bit field indicating the modulation / coding scheme of the data scheduled by the DCI, i.e., a Modulation and coding scheme (MCS) field.

[0091] Optionally, the slots in which the group SPS PDSCH is placed, and the method for indicating S and L, are as follows. The aforementioned DCI, carried on the PDCCH scrambled by G-CS-RNTI, indicates a row in the time-domain resource table. The time-domain resource table can be a table predefined by the protocol or a table constructed using higher-layer signaling. The table contains multiple rows, each containing parameters K0, S, and L. K0 indicates the number of slots between the slot in which the PDCCH is placed and the slot in which the PDSCH is placed. S and L can be encoded together as a single parameter, namely the start and length indicator value (SLIV), or as two independent parameters represented by (S,L). For example, Table 1 shows a time-domain resource table. Specifically, the DCI may include a bit field indicating the row index, and the bit field may occupy 2 bits. For example, if DCI includes index 1, it means that DCI indicates K0 is 1 and (S,L) is (1,2). In other words, if a terminal device receives a DCI scrambled by G-CS-RNTI in the nth slot, the terminal device may receive a group SPS PDSCH scheduled by the DCI in the (n+1)th slot. Specifically, the terminal device receives a group SPS PDSCH scheduled by the DCI on symbols 1 and 2 in the (n+1)th slot.

[0092] [Table 1]

[0093] Optionally, a method for indicating the slot where feedback information corresponding to a group SPS PDSCH is located is as follows: The DCI contains one indication piece of information. Specifically, the PDSCH-to-HARQ_feedback timing indicator bit field may be used to represent the indication piece of information. The number of bits that can be occupied by the bit field is [0,3]. The bit field indicates the specific point in time when the terminal device performs feedback, specifically, when it sends the corresponding feedback information after receiving a group SPS PDSCH. Optionally, the indication piece of information may be the value of K1 in the K1 set. The K1 set (e.g., the dl-DataToUL-ACK field) may be a set constructed using higher-layer signaling. The value of K1 indicates the number of slots between the slot where the group SPS PDSCH is located and the corresponding feedback information. Assume that the group SPS PDSCH is in the (n+1)th slot. In this case, the feedback information corresponding to the group SPS PDSCH is in the (n+1+K1)th slot. For example, the value of K1 could be 4, and the feedback information could specifically be ACK information or NACK information. A slot could be a sub-slot instead.

[0094] After determining the feedback slots of the group SPS PDSCH based on the DCI indication, the terminal device further needs to determine the specific feedback resources that can be occupied by the feedback information. The method by which the terminal device determines the feedback resources can be implemented in relation to the following methods.

[0095] The terminal device first determines the number of bits of feedback information corresponding to the group SPS PDSCH that needs to be fed back in the feedback slot, for example, by using the sum of the number of bits of all feedback information belonging to the group SPS PDSCH that needs to be fed back in the feedback slot as the number of bits of feedback information, and then, based on the number of bits of feedback information, selects a PUCCH resource from a semi-persistent scheduling PUCCH resource set pre-configured by the network device to send the feedback information of the group SPS PDSCH.

[0096] For example, suppose a network device configures four PUCCH resources for terminal devices. The first PUCCH resource is used to send feedback information for group SPS PDSCH if the number of bits in the feedback information is 2 or less. The second PUCCH resource is used if the number of bits is between 3 and N1. The third PUCCH resource is used if the number of feedback bits is greater than N1 and less than or equal to N2. The fourth PUCCH resource is used if the number of feedback bits is greater than N2 and less than or equal to N3. N1 is less than N2 and greater than 2, and N2 is less than N3. N1, N2, and N3 are also indicated by the network device sending configuration information (e.g., in upper-layer signaling). If no indication is performed, N3 defaults to 1706.

[0097] Optionally, the DCI scrambled by G-CS-RNTI may further include information indicating a specific semi-persistent scheduling SPS configuration to be activated using the DCI. For example, if a network device configures multiple SPS configurations for a terminal device, specifically, the HARQ process number (HPN) bit field in the DCI may indicate the aforementioned semi-persistent scheduling SPS configuration to be activated, and the number of bits that can be occupied by that bit field is [0,4]. The terminal device may use the value of the HARQ process number to decide to activate a multicast-based semi-persistent scheduling SPS transmission, specifically, this corresponds to activating an SPS configuration with a specific sequence number among multiple SPS configurations. Alternatively, if a network device configures a single SPS configuration for a terminal device, the value of the HARQ process number in the DCI is 0 by default.

[0098] Optionally, the DCI scrambled by G-CS-RNTI may further include information indicating that the group SPS PDSCH scheduled by the DCI is the first transmitted data. For example, the DCI may include one bit field, which is represented as a new data indicator (NDI). An NDI value of 0 indicates that the group SPS PDSCH scheduled by the DCI is the first transmitted data.

[0099] Furthermore, the network device does not need to initially send a DCI for scheduling when it subsequently sends a group SPS PDSCH, and the terminal device receives the group SPS PDSCH based on the activated SPS configuration. See Figure 2. In time unit 1, before the network device sends the group SPS PDSCH for the first time in time unit 2, it sends a DCI scrambled by G-CS-RNTI to schedule the group SPS PDSCH. The DCI is used to activate multicast-based semi-static SPS transmission. Optionally, the DCI includes information indicating a semi-persistent scheduling SPS configuration, and the DCI is specifically used to activate the SPS configuration. When the network device sends a group SPS PDSCH in a subsequent time unit, it no longer needs to send any other DCIs, and the terminal device can receive subsequent group SPS PDSCHs based on the activated SPS configuration described above. For example, Figure 2 shows that the terminal device subsequently receives group SPS PDSCHs periodically in time units 3 through 6 and does not need to receive any DCIs.

[0100] It should be noted here that the time unit is a time unit for SPS scheduling and is a time-domain concept. A time unit can be a unit of frame, subframe, slot, or symbol. For example, in a 5G NR system, 15kHz subcarrier spacing is used, and the time length of one slot is 1ms. When extended cyclic prefixes are used, one slot contains 12 symbols. When normal cyclic prefixes are used, one slot contains 14 symbols. Here, symbols referred to as time-domain symbols can be orthogonal frequency division multiplexing (OFDM) symbols. It should be understood that time units 1 through 6 in Figure 2 do not mean that time units 1 through 6 are consecutive time units. For example, there is one SPS periodicity between two adjacent time units between time units 2 through 6.

[0101] Optionally, a terminal device may determine the slot location where subsequent group SPS PDSCHs are placed based on the SPS transmission periodicity P configured by the upper layer. For example, if the SPS transmission periodicity P is 1 ms, the time domain duration of one slot is 1 ms, and the group SPS PDSCH of the first time is on symbols 1 and 2 in the (n+1)th slot, then when multicast SPS is activated, the location of the group SPS PDSCH will occupy symbols 1 and 2 in each slot, starting from the (n+1)th slot, where n is an integer greater than 1. It can be understood that the time units shown in Figure 2 may be slots. In this example, Figure 2 shows that time unit 1, where DCI is scrambled by G-CS-RNTI, is the nth slot, and the location of the group SPS PDSCH will start from the (n+1)th slot, i.e., starting from time unit 2, then time unit 3, time unit 4, and so on. In addition, the transmission periodicity P can be any other value, and this depends on the upper layer configuration. For example, if the SPS transmission periodicity P configured by the upper layer is 2ms, and the group SPS PDSCH at the first time is on symbols 1 and 2 in the (n+1)th slot, then when multicast SPS is activated, the location of the group SPS PDSCH will start from the (n+1)th slot, occupying symbols 1 and 2 in each slot with a 1-slot gap between them, i.e., the location of the group SPS PDSCH will be the (n+1+x*2)th slot, where x is a non-negative integer.In this example, it is assumed that the duration of one time unit is 1 ms. In this case, if the SPS transmission periodicity is 1 ms, the SPS transmission periodicity corresponds to one time unit, or in other words, the SPS PDSCH is transmitted in each time unit. If the SPS transmission periodicity is 2 ms, the SPS transmission periodicity corresponds to two time units, or in other words, the SPS PDSCH is transmitted with an interval of one time unit between them.

[0102] The aforementioned upper layer may be understood as an upper layer protocol layer and includes at least one protocol layer above the physical layer, namely, a media access control (MAC) layer, a radio link control (RLC) layer, a packet data convergence protocol (PDCP) layer, a radio resource control (RRC) layer, and a non-access stratum (NAS). Correspondingly, in embodiments of this application, the upper layer signaling may be NAS signaling, RRC messages, or media access control (MAC) control elements (CE). RRC messages may include individual RRC messages or broadcast / multicast RRC messages. This is not limited to embodiments of this application.

[0103] A2: Retransmitting data related to multicast-based semi-persistent scheduling transmission.

[0104] Group SPS PDSCH may be retransmitted in the following three cases:

[0105] Case 1: If the feedback information for a group SPS PDSCH is NACK information for many terminal devices, specifically if many terminal devices have not successfully received the group SPS PDSCH, then a network device may send the retransmission data for the group SPS PDSCH in multicast mode, or in other words, retransmit the group SPS PDSCH.

[0106] A quantity threshold may be set. In a group of terminal devices, if a number of terminal devices greater than or equal to the specified quantity threshold have not successfully received the group SPS PDSCH transmitted by the network device, and all of them feed back NACK information to the network device, the network device may determine that many terminal devices have not successfully received the group SPS PDSCH. For example, if a group of terminal devices includes 6 terminal devices, the specified quantity threshold may be 3. When the feedback information sent to the network device by 3 or more terminal devices is NACK information, the network device may send the retransmission data of the unsuccessfully received group SPS PDSCH in multicast mode.

[0107] For example, after receiving NACK information sent by multiple terminal devices, a network device may send a single DCI scrambled by G-CS-RNTI to multiple terminal devices in multicast mode. Here, the DCI is used to schedule retransmission data, which may be one of several SPS PDSCHs that utilize the activated multicast-based SPS transmission described above. The DCI includes an NDI, where an NDI value of 1 indicates that the PDSCH scheduled by the DCI is retransmission data. The DCI may further include an HPN indicating the HARQ process occupied by the retransmission. Optionally, the HARQ process occupied by the retransmission, as indicated by the HPN, is the same as the HARQ process calculated based on the activated SPS configuration. In other words, a terminal device can receive DCI scrambled by G-CS-RNTI, know that DCI schedules retransmission data based on NDI, which has a value of 1, and know the HARQ process occupied to receive retransmission data based on HPN in DCI, thereby facilitating soft combination of retransmission data.

[0108] Case 2: If the feedback information for the group SPS PDSCH is NACK information for a small number of terminal devices, specifically if a small number of terminal devices have not successfully received the group SPS PDSCH, the network device may separately send the retransmission data of the group SPS PDSCH in unicast mode to the terminal devices that have not successfully received the group SPS PDSCH.

[0109] A quantity threshold may be set. In a group of receiving terminal devices, if a number of terminal devices less than the specified quantity threshold have not successfully received the group SPS PDSCH transmitted by the network device and feed back NACK information to the network device, the network device may determine that a small number of terminal devices have not successfully received the group SPS PDSCH. For example, if the group of terminal devices includes 6 terminal devices, the specified quantity threshold may be 3. When the feedback information sent to the network device by one or two terminal devices is NACK information, the network device may send retransmission data of the unsuccessfully received group SPS PDSCH in unicast mode.

[0110] Case 3: A network device configures or notifies a terminal device of its retransmission scheduling method. Specifically, in a group of terminal devices, the network device configures or notifies some terminal devices that their retransmission scheduling method is unicast-based, and others that their retransmission scheduling method is multicast-based. If a terminal device whose retransmission scheduling method is configured or notified to be unicast-based has not successfully received the group SPS PDSCH sent by the network device and feeds back NACK information to the network device, the network device transmits the retransmission data of the group SPS PDSCH to the terminal device through unicast-based retransmission scheduling. If a terminal device whose retransmission scheduling method is configured or notified to be multicast-based has not successfully received the group SPS PDSCH sent by the network device and feeds back NACK information to the network device, the network device transmits the retransmission data of the group SPS PDSCH to the terminal device through multicast-based retransmission scheduling. For example, suppose a group of terminal devices includes six terminal devices, where terminal device #1 is configured with unicast-based retransmission scheduling, and terminal devices #2 through #6 are configured with multicast-based retransmission scheduling. If the feedback information sent by terminal device #1 to the network device is NACK information, the network device may send the retransmission data for the group SPS PDSCH that was not successfully received to terminal device #1 in unicast mode. If the feedback information sent by any one of terminal devices #2 through #6 to the network device is NACK information, the network device sends the retransmission data for the group SPS PDSCH that was not successfully received to terminal devices #2 through #6 in multicast mode.

[0111] Optionally, after receiving NACK information transmitted by a terminal device, the network device may send a DCI scrambled by a configured scheduling network temporary identifier (CS-RNTI) to the terminal device. The DCI is used to schedule retransmission data. The DCI includes an NDI, where a value of 1 indicates that the group SPS PDSCH scheduled by the DCI is retransmission data. Here, the DCI includes an HPN field indicating the HARQ process occupied by the retransmission. Optionally, the HARQ process occupied by the retransmission, as indicated by the HPN, is the same as the HARQ process calculated based on the activated SPS configuration. In other words, the terminal device receives the DCI scrambled by the CS-RNTI, and based on the NDI value of 1 in the DCI, it can know that the DCI is scheduling retransmission data, and based on the HPN in the DCI, it can know the HARQ process occupied to receive the retransmission data, facilitating soft combinations of retransmission data. It should be noted that in embodiments of this application, the CS-RNTI identifies a unicast transmission and may be configured by a network device for a single terminal device. Of course, the CS-RNTI may be replaced by other identifiers if those identifiers are capable of identifying unicast transmissions. This is not limited to embodiments of this application. When terminal devices 1 and 2 transmit NACKs, it may be understood that the network device transmits DCIs separately to the two terminal devices. For example, the network device transmits the DCI scrambled by terminal device 1's CS-RNTI to terminal device 1, retransmitting the aforementioned SPS PDSCH to terminal device 1 in unicast mode, and transmits the DCI scrambled by terminal device 2's CS-RNTI to terminal device 2, retransmitting the aforementioned SPS PDSCH to terminal device 2 in unicast mode.

[0112] For example, Figure 3 illustrates the unicast retransmission scheduling mechanism described above. Assume that a single terminal device has not successfully received the group SPS PDSCH transmitted by the network device in time unit 1. In this case, the single terminal device determines that the feedback time unit for the feedback information is time unit 2, based on the PDSCH-to-HARQ_feedback timing indicator in the DCI scrambled by G-CS-RNTI in activation phase A1, and transmits NACK information to the network device on the PUCCH in time unit 2. After receiving the PUCCH, the network device determines that the terminal device has fed back a NACK. In this case, the network device transmits the retransmission data of the group SPS PDSCH to the terminal device in unicast mode. Specifically, the network device transmits the DCI scrambled by CS-RNTI to the terminal device in time unit 3, and the terminal device blindly detects the DCI scrambled by CS-RNTI on the PDCCH. The HARQ process indicated by HPN in the DCI is the same as the HARQ process calculated based on the activated SPS configuration. For example, both are HARQ process N. If the NDI value in DCI is 1, the terminal device knows that the DCI scrambled by CS-RNTI will schedule retransmission data, which is the retransmission data of the aforementioned SPS PDSCH. In this case, after receiving the retransmission data of the group SPS PDSCH, the terminal device may perform a soft combination with the data in the initially transmitted group SPS PDSCH.

[0113] In embodiments of this application, a network device can use DCI scrambled by CS-RNTI to perform retransmission scheduling for multicast SPS data, or in other words, can transmit retransmission data of a group SPS PDSCH to a single terminal device in unicast mode. In this scheme, no new RNTI is introduced, and resources used by the terminal device to blindly detect DCI can be saved.

[0114] A3: Deactivate multicast-based semi-persistent scheduling transmission.

[0115] A network device may send a deactivated DCI, scrambled by G-CS-RNTI, to multiple terminal devices. In the deactivated DCI, the redundancy version field is all 0, the modulation and coding scheme field is all 1, and the frequency domain resource assignment field is all 1 (i.e., Type 1) or all 0 (i.e., Type 0). Based on the aforementioned information in the deactivated DCI, terminal devices may know that the deactivated DCI is used to deactivate multicast-based semi-persistent scheduling SPS transmissions. The deactivated DCI may also include other information, such as the HPN. The value of the HPN may be the same as the value of the HPN in the DCI during the activation phase (A1). Based on the HPN in the deactivated DCI, terminal devices may deactivate the SPS configuration indicated by the HPN and will no longer receive the group SPS PDSCH of the deactivated SPS configuration in subsequent time units. For example, as shown in Figure 4, the network device transmits a deactivated DCI scrambled by G-CS-RNTI in time unit 1. In this case, the terminal device blind-detects the deactivated DCI on the PDCCH and, based on the HPN in the deactivated DCI, decides that it will no longer receive the group SPS PDSCH for the SPS configuration corresponding to the HPN. Specifically in Figure 4, the "×" can be understood to mean that the terminal device will no longer receive the group SPS PDSCH in time units 2 through 6, or that the network device will no longer transmit the group SPS PDSCH in time units 2 through 6.

[0116] It should be noted that Solution 1 may include one or more of the aforementioned phases A1 to A3, and the execution sequence of phases A1 to A3 may be determined based on actual requirements. This is not limited to the embodiments of this application.

[0117] Solution 2:

[0118] The DCI may include indication information indicating a dynamic scheduling transmission or a semi-persistent scheduling SPS transmission. The DCI and the group-radio network temporary identifier (G-RNTI) jointly indicate multicast dynamic scheduling or multicast semi-persistent scheduling. It should be noted that the G-RNTI identifies multicast transmissions and may be configured by a network device for a group of terminal devices. Of course, the G-RNTI may be replaced by other identifiers if those identifiers are capable of identifying multicast transmissions. This is not limited to the embodiments of this application.

[0119] In optional implementations, the DCI may include a target bit field indicating dynamic scheduling or semi-persistent scheduling SPS. The target bit field may occupy 1 bit. When the value of the target bit field is 0, it indicates that the DCI indicates dynamic scheduling, or when the value of the target bit field is 1, it indicates that the DCI indicates semi-persistent scheduling SPS. Alternatively, conversely, when the value of the target bit field is 1, it indicates that the DCI indicates dynamic scheduling, or when the value of the target bit field is 0, it indicates that the DCI indicates semi-persistent scheduling SPS.

[0120] In other optional implementations, considering that both multicast dynamic scheduling and multicast semi-persistent scheduling are downlink communications, when DCI and G-RNTI jointly indicate multicast dynamic scheduling or multicast semi-persistent scheduling, the description of the Identifier for DCI formats field in the conventional DCI format may be changed, and the value of the Identifier for DCI formats field is used to distinguish between multicast dynamic scheduling and multicast semi-persistent scheduling. For example, if the value of the Identifier for DCI formats field in DCI is 0, it indicates that DCI indicates dynamic scheduling, or if the value of the Identifier for DCI formats field in DCI indicates that DCI indicates semi-persistent scheduling SPS. Alternatively, conversely, if the value of the Identifier for DCI formats field in DCI is 1, it indicates that DCI indicates dynamic scheduling, or if the value of the Identifier for DCI formats field in DCI is 0, it indicates that DCI indicates semi-persistent scheduling SPS.

[0121] Optionally, based on the aforementioned scheme in which G-RNTI and DCI perform joint indication, the activation of multicast semi-persistent scheduling, retransmissions related to multicast semi-persistent scheduling, and deactivation of multicast semi-persistent scheduling may be performed in relation to the schemes described in B1 to B3 below.

[0122] B1: Activate multicast-based semi-persistent scheduling transmission.

[0123] A network device may configure the same group-radio network temporary identifier (G-RNTI) for multiple terminal devices. Before sending the same downlink data (i.e., group SPS PDSCH) to multiple terminal devices for the first time, the network device sends a single DCI scrambled by the G-RNTI. The DCI includes information indicating a multicast-based semi-persistent scheduling transmission, such as the target bit field described above. A terminal device blindly detects the DCI scrambled by the G-RNTI on the PDCCH and determines that the DCI contains information indicating an SPS configuration. In this case, the terminal device can activate the multicast SPS configuration based on the DCI scrambled by the G-RNTI and receive the group SPS PDSCH sent by the network device for the first time.

[0124] Optionally, the DCI used for activation, which is scrambled by G-RNTI, may also be understood as the activated DCI. For other content included in the DCI transmitted by the network device and scrambled by G-RNTI, see the description of the content included in the DCI scrambled by G-CS-RNTI in A1. Further details are not described again in the embodiments of this application.

[0125] Furthermore, the network device does not need to initially send a DCI for scheduling, and the terminal device receives the group SPS PDSCH based on the activated SPS configuration. See Figure 5. In time unit 1, before the network device sends the group SPS PDSCH for the first time in time unit 2, it sends a DCI scrambled by G-RNTI to schedule the group SPS PDSCH. The DCI is used to activate multicast-based semi-static SPS transmission. Optionally, the DCI includes information indicating a semi-persistent scheduling SPS configuration, and the DCI is specifically used to activate the SPS configuration. When the network device sends the group SPS PDSCH in subsequent time units, it no longer needs to send any other DCIs, and the terminal device can receive subsequent group SPS PDSCHs based on the activated SPS configuration described above. For example, Figure 5 shows that the terminal device subsequently receives group SPS PDSCHs periodically in time units 3 through 5 without needing to receive any other DCIs.

[0126] In addition, network devices can perform multicast dynamic scheduling while also performing multicast semi-persistent scheduling as an alternative. Figure 5 further illustrates that in time unit 1 preceding time unit 2, which is the first time a network device transmits data utilizing multicast-based dynamic scheduling transmission, such as a Dynamic scheduling PDSCH (DYN PDSCH), the network device transmits a DCI scrambled by G-RNTI to schedule a DYN PDSCH. Here, the DCI contains information indicating dynamic scheduling. In this case, the terminal device can blindly detect the two DCIs scrambled by G-RNTI on the PDCCH in time unit 1. For the purpose of distinction, DCI-1 and DCI-2 are used for display in Figure 5. DCI-1 schedules a DYN PDSCH in time unit 2. DCI-2 schedules a group SPS PDSCH in time unit 2 and subsequent time units. The aforementioned example is used where a target bit value of 0 represents dynamic scheduling and a target bit value of 1 represents semi-persistent scheduling. In this case, the target bit value in DCI-1 is 0, and the target bit value in DCI-2 is 1.

[0127] B2: Retransmitting data related to multicast-based semi-persistent scheduling transmission.

[0128] Group SPS PDSCH may be retransmitted in the following three cases:

[0129] Case 1: If the feedback information for a group SPS PDSCH is NACK information for many terminal devices, specifically if many terminal devices have not successfully received the group SPS PDSCH, a network device may retransmit the group SPS PDSCH data in multicast mode.

[0130] Optionally, the network device may schedule the retransmission data of the aforementioned group SPS PDSCH based on the DCI scrambled by G-RNTI. A specific implementation may be carried out in relation to the solution in Case 1 of A2. Further details are not described again in the embodiments of this application.

[0131] Case 2: If the feedback information for the group SPS PDSCH is NACK information for a small number of terminal devices, specifically if a small number of terminal devices have not successfully received the group SPS PDSCH, the network device may separately send the retransmission data for the group SPS PDSCH in unicast mode to the terminal devices that have not successfully received the group SPS PDSCH.

[0132] Optionally, the network device may schedule the retransmission data of the aforementioned group SPS PDSCH based on the DCI scrambled by CS-RNTI. A specific implementation may be carried out in relation to the solution in Case 2 of A2. Further details are not described again in the embodiments of this application.

[0133] Case 3: If a terminal device whose retransmission scheduling scheme is configured or notified to be unicast-based does not successfully receive the group SPS PDSCH and sends a feedback information NACK, the network device will send the retransmission data of the group SPS PDSCH to the terminal device whose retransmission scheduling scheme is configured or notified to be unicast-based using a unicast-based retransmission scheduling scheme. If a terminal device whose retransmission scheduling scheme is configured or notified to be multicast-based does not successfully receive the group SPS PDSCH and sends a feedback information NACK, the network device will send the retransmission data of the group SPS PDSCH to the terminal device whose retransmission scheduling scheme is configured or notified to be multicast-based using a multicast-based retransmission scheduling scheme.

[0134] Optionally, a network device may schedule the retransmission data of the aforementioned group SPS PDSCH to terminal devices configured to have a unicast-based retransmission scheduling scheme based on DCI scrambled by CS-RNTI, or may schedule the retransmission data of the aforementioned group SPS PDSCH to terminal devices configured to have a multicast-based retransmission scheduling scheme based on DCI scrambled by G-RNTI or G-CS-RNTI. Specific implementations may be carried out in relation to the solution in Case 3 of A2. Further details are not described again in the embodiments of this application.

[0135] B3: Deactivate multicast-based semi-persistent scheduling transmission.

[0136] A network device may send a deactivation DCI scrambled by G-RNTI to multiple terminal devices. In the deactivation DCI, the Redundancy Version field is all 0, the Modulation and coding scheme field is all 1, and the Frequency domain resource assignment field is all 1 (i.e., Type 1) or all 0 (i.e., Type 0). Based on the aforementioned information in the deactivation DCI, terminal devices may know that the deactivation DCI will be used to deactivate a multicast semi-persistent scheduling SPS. The deactivation DCI may also contain other information, such as the HPN. The value of the HPN may be the same as the value of the HPN in the DCI during the activation phase (A1). Based on the HPN in the deactivation DCI, terminal devices may deactivate the SPS configuration indicated by the HPN and will no longer receive a group SPS PDSCH of the deactivated SPS configuration in subsequent time units. For example, as shown in Figure 6, the network device transmits a deactivated DCI scrambled by G-RNTI in time unit 1. In this case, the terminal device blind-detects the deactivated DCI on the PDCCH and, based on the HPN in the deactivated DCI, decides that it will no longer receive the group SPS PDSCH for the SPS configuration corresponding to the HPN. Specifically in Figure 6, the "×" can be understood to mean that the terminal device will no longer receive the group SPS PDSCH in time units 2 through 5, or that the network device will no longer transmit the group SPS PDSCH in time units 2 through 5.

[0137] Solution 1 may include one or more of the aforementioned phases B1 to B3, and it should be noted that the execution sequence of phases B1 to B3 may be determined based on actual requirements. This is not limited to the embodiments of this application.

[0138] According to Solution 2 provided in the embodiments of this application, a method representing semi-persistent scheduling or dynamic scheduling is defined in DCI, thereby enabling G-RNTI to be used for dynamically scheduling multicast data or for semi-persistently scheduling multicast data. This expands the application scenarios of G-RNTI, saves blind detection resources on the terminal device side, and reduces control signaling overhead when scheduling multicast downlink data.

[0139] Based on Solutions 1 and 2 described above, please refer to Figure 7. Embodiments of this application provide a schematic flowchart of a data transmission method. The method includes the following steps.

[0140] S701: A network device may transmit first multicast data to multiple terminal devices using a multicast semi-persistent scheduling scheme; in other words, each terminal device may receive first multicast data using multicast-based semi-persistent scheduling SPS transmission. For example, Figure 7 shows three terminal devices, which are labeled as the first terminal device, the second terminal device, and the third terminal device. In Figure 7, it should be noted that the network device does not transmit the first multicast data three times, but only once, and all three terminal devices are able to receive the multicast data. First multicast data using multicast-based semi-persistent scheduling SPS transmission may be interpreted as "first multicast data using a multicast-based SPS transmission."

[0141] Multicast-based semi-persistent scheduling transmission primarily involves the following transmissions during the activation phase and transmissions after activation. During the activation phase, multicast-based semi-persistent scheduling SPS transmissions must be activated using DCI. During the activation phase, the first multicast data transmitted by the network device can be understood as data containing scheduling information. After activation, the first multicast data transmitted by the network device can be understood as data without scheduling information or data without DCI.

[0142] In an optional implementation, the implementation corresponds to A1 in Solution 1 described above. A network device may transmit a second DCI scrambled by the Group Configuration Scheduling Radio Network Temporary Identifier G-CS-RNTI to multiple terminal devices, and the second DCI is used to activate multicast-based semi-persistent scheduling SPS transmission. In this case, each terminal device may activate multicast-based semi-persistent scheduling SPS transmission based on the second DCI and receive the aforementioned first multicast data scheduled by the second DCI, as well as subsequent first multicast data without scheduling information.

[0143] In other optional implementations, the implementation corresponds to B1 in Solution 2 described above. The network device may transmit a third DCI scrambled by the Group Radio Network Temporary Identifier G-RNTI to multiple terminal devices, and the third DCI is used to activate multicast-based semi-persistent scheduling SPS transmission. In this case, the value of the first indication information contained in the third DCI is the first value. The value of the first indication information includes either the first or second value, where the first value indicates multicast-based semi-persistent scheduling SPS transmission, and the second value indicates multicast-based dynamic scheduling transmission. Optionally, the first indication information may be a target bit or an identifier for the DCI format described in Solution 2 described above. The first value may be 0 and the second value may be 1, or the first value may be 1 and the second value may be 0. In this case, each terminal device can activate multicast-based semi-persistent scheduling SPS transmission based on the third DCI and receive the aforementioned first multicast data scheduled by the third DCI, as well as subsequent first multicast data that does not have scheduling information.

[0144] In addition, it should be noted that the third DCI does not contain information indicating that the third DCI is used to schedule uplink or downlink transmissions. For example, when the target bit is used in the third DCI to indicate multicast-based semi-persistent scheduling transmission or multicast-based dynamic scheduling transmission, the third DCI does not contain an identifier for the DCI format. When an identifier for the DCI format is used in the third DCI to indicate multicast-based semi-persistent scheduling transmission or multicast-based dynamic scheduling transmission, the description or definition of the identifier for the DCI format cannot indicate that the third DCI is used to schedule uplink or downlink transmissions.

[0145] Optionally, if the New Data Indicator NDI value in the second DCI is 0, it indicates that the second DCI will schedule the data to be transmitted first. Similarly, if the New Data Indicator NDI value in the third DCI is 0, it indicates that the third DCI will schedule the data to be transmitted first.

[0146] S702: The network device receives a feedback information NACK from the first terminal device; in other words, the first terminal device has not successfully received the aforementioned first multicast data.

[0147] S703: The network device transmits a first DCI scrambled by CS-RNTI and a first data to a first terminal device, the first data being a retransmission of the first multicast data, and the first data being data that utilizes unicast-based transmission.

[0148] Optionally, if the new data indicator NDI value in the first DCI is 1, it indicates that the first DCI is scheduling retransmitted data.

[0149] In addition, it should be noted that if a network device receives a large amount of NACK information, for example, if the network device receives feedback information NACKs from both the first and second terminal devices based on the RNTI used in the activation phase described above, the network device may perform multicast retransmission scheduling based on G-CS-RNTI or G-RNTI, and may, for example, transmit second multicast data. The second multicast data is a retransmission of the first multicast data and can be understood as multicast data. For specific implementations, please refer to the solutions in A2 and B2. Further details are not described again in this embodiment of the present application.

[0150] S704: The terminal device receives a first DCI and receives first data based on the first DCI.

[0151] In this embodiment of the present application, multicast transmission is performed through semi-persistent scheduling without the need to transmit scheduling information, i.e., DCI, each time multicast data is transmitted, thereby reducing control signaling overhead. In addition, when individual terminal devices have not successfully received multicast data, the multicast data is retransmitted to the terminal devices in unicast mode instead of scheduling data retransmission in multicast mode. In this way, the occupation of downlink resources can be further reduced and data transmission efficiency can be improved.

[0152] Furthermore, if SPS transmission needs to be deactivated, the network device may further transmit a fourth DCI scrambled by G-RNTI or G-CS-RNTI, which is used to deactivate multicast-based semi-persistent scheduling SPS transmission. The contents of the fourth DCI may be performed in relation to the scheme in A3 or B3. Further details will not be described again.

[0153] Based on the same idea, Figure 8 provides a possible exemplary block diagram of a data transmission device according to the present application. The device 800 may exist in the form of software or hardware. The device 800 may include a processing unit 802 and a communication unit 803. In implementation, the communication unit 803 may include a receiving unit and a transmitting unit. The processing unit 802 is configured to control and manage the actions of the device 800. The communication unit 803 is configured to support the device 800 when communicating with other network entities. The device 800 may further include a storage unit 801 configured to store the program code and data of the device 800.

[0154] The processing unit 802 may be a processor or controller, such as a central processing unit (CPU), a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. The processing unit may implement or execute various exemplary logic blocks, modules, and circuits described in relation to the disclosures herein. Alternatively, the processor may be a combination of processors that perform computing functions, such as a combination of one or more microprocessors, or a combination of a DSP and a microprocessor. The storage unit 801 may be memory. The communication unit 803 is an interface circuit of the device, configured to receive signals from other devices. For example, when the device is implemented in the form of a chip, the communication unit 803 is an interface circuit used by the chip to receive signals from other chips or devices, or an interface circuit used by the chip to transmit signals to other chips or devices.

[0155] In the solution, device 800 may be a terminal device in any of the embodiments described above, or a chip used in a terminal device. For example, when device 800 is a terminal device, processing unit 802 may be, for example, a processor, and communication unit 803 may be, for example, a transceiver. Optionally, the transceiver may include a radio frequency circuit, and the storage unit may be, for example, memory. For example, when device 800 is a chip used in a terminal device, processing unit 802 may be, for example, a processor, and communication unit 803 may be, for example, an input / output interface, pins, or circuitry. Processing unit 802 may execute computer executable instructions stored in the storage unit. Optionally, the storage unit may be an internal storage unit of the chip, such as a register or cache. Alternatively, the storage unit may be a storage unit located inside the terminal device but outside the chip, such as read-only memory (ROM), other types of static storage devices capable of storing static information and instructions, or random access memory (RAM).

[0156] The following describes in detail the functions, also referred to as alternative operations, that are performed by units included in the device 800 used in terminal devices.

[0157] The communication unit 803 is configured to receive first multicast data that utilizes multicast-based semi-persistent scheduling SPS transmission.

[0158] The communication unit 803 is further configured to receive a first downlink control information DCI, which is scrambled by a configuration scheduling radio network temporary identifier CS-RNTI.

[0159] The processing unit 802 is configured to receive first data based on a first DCI through the communication unit 803, and the first data is a retransmission of the first multicast data.

[0160] In this embodiment of the present application, multicast transmission is performed through semi-persistent scheduling without the need to transmit scheduling information, i.e., DCI, each time multicast data is transmitted, thereby reducing control signaling overhead. In addition, when data needs to be retransmitted to individual terminal devices, multicast data is retransmitted to the terminal devices in unicast mode instead of scheduling data retransmission in multicast mode. In this way, the occupation of downlink resources can be further reduced and data transmission efficiency can be improved.

[0161] In an optional implementation, before the communication unit 803 receives the first DCI, the processing unit 802 is further configured to determine that the reception of the first multicast data has failed and to send feedback information such as a NACK, the feedback information indicating that the reception of the first multicast data has failed.

[0162] In an optional implementation, the communication unit 803 is further configured to receive a second DCI scrambled by the group configuration scheduling radio network temporary identifier G-CS-RNTI, the second DCI being used to activate multicast-based semi-persistent scheduling SPS transmissions.

[0163] In an optional implementation, the communication unit 803 is further configured to receive a third DCI scrambled by the group radio network temporary identifier G-RNTI, the third DCI being used to activate multicast-based semi-persistent scheduling SPS transmission, the value of the first indication information contained in the third DCI being a first value, the value of the first indication information being a first value or a second value, the first value indicating multicast-based semi-persistent scheduling SPS transmission and the second value indicating multicast-based dynamic scheduling transmission.

[0164] In an optional implementation, the third DCI does not include information indicating that the third DCI is used to schedule uplink or downlink transmissions.

[0165] In the optional implementation, the new data indicator NDI value in the first DCI is 1, the new data indicator NDI value in the second DCI is 0, and the new data indicator NDI value in the third DCI is 0.

[0166] In the implementation of optional communication, unit The system is further configured to receive a fourth DCI scrambled by a group radio network temporary identifier G-RNTI, the fourth DCI being used to deactivate multicast-based semi-persistent scheduling SPS transmissions, or to receive a fourth DCI scrambled by a group configuration scheduling radio network temporary identifier G-CS-RNTI, the fourth DCI being used to deactivate multicast-based semi-persistent scheduling SPS transmissions.

[0167] In other solutions, device 800 may be a network device in any of the embodiments described above, or a chip used in a network device. For example, when device 800 is a network device, processing unit 802 may be, for example, a processor, and communication unit 803 may be, for example, a transceiver. Optionally, the transceiver may include a radio frequency circuit, and the storage unit may be, for example, memory. For example, when device 800 is a chip used in a network device, processing unit 802 may be, for example, a processor, and communication unit 803 may be, for example, an input / output interface, pins, or circuitry. Processing unit 802 may execute computer executable instructions stored in the storage unit. Optionally, the storage unit may be a storage unit on the chip, such as a register or cache. Alternatively, the storage unit may be a read-only memory (ROM) located inside the network device and outside the chip, or other types of static storage devices capable of storing static information and instructions, as well as random access memory (RAM).

[0168] The following describes in detail the functions, also referred to as alternative operations, that are performed by units included in device 800 used in network devices.

[0169] The processing unit 802 is configured to generate first multicast data that utilizes multicast-based semi-persistent scheduling SPS transmission.

[0170] The communication unit 803 is configured to transmit the first multicast data.

[0171] The communication unit 803 is further configured to transmit a first downlink control information DCI, which is scrambled by a configuration scheduling radio network temporary identifier CS-RNTI, which is used to schedule first data, which is retransmitted data of first multicast data.

[0172] In this embodiment of the present application, multicast transmission is performed through semi-persistent scheduling without the need to transmit scheduling information, i.e., DCI, each time multicast data is transmitted, thereby reducing control signaling overhead. In addition, when data needs to be retransmitted to individual terminal devices, multicast data is retransmitted to the terminal devices in unicast mode instead of scheduling data retransmission in multicast mode. In this way, the occupation of downlink resources can be further reduced and data transmission efficiency can be improved.

[0173] In an optional implementation, the communication unit 803 is further configured to transmit a second DCI scrambled by the group configuration scheduling radio network temporary identifier G-CS-RNTI, the second DCI being used to activate multicast-based semi-persistent scheduling SPS transmission.

[0174] In an optional implementation, the communication unit 803 is further configured to transmit a third DCI scrambled by the group radio network temporary identifier G-RNTI, the third DCI being used to activate multicast-based semi-persistent scheduling SPS transmission, the value of the first indication information contained in the third DCI being a first value, the value of the first indication information being a first value or a second value, the first value indicating multicast-based semi-persistent scheduling SPS transmission and the second value indicating multicast-based dynamic scheduling transmission.

[0175] In an optional implementation, the third DCI does not include information indicating that the third DCI is used to schedule uplink or downlink transmissions.

[0176] In the optional implementation, the new data indicator NDI value in the first DCI is 1, the new data indicator NDI value in the second DCI is 0, and the new data indicator NDI value in the third DCI is 0.

[0177] In an optional implementation, the communication unit 803 is further configured to transmit a fourth DCI scrambled by the group radio network temporary identifier G-RNTI, the fourth DCI being used to deactivate multicast-based semi-persistent scheduling SPS transmissions, or to transmit a fourth DCI scrambled by the group configuration scheduling radio network temporary identifier G-CS-RNTI, the fourth DCI being used to deactivate multicast-based semi-persistent scheduling SPS transmissions.

[0178] Figure 9 is a schematic diagram of a communication device according to this application. The device may be a terminal device or a network device in the embodiments described above. Device 900 includes a processor 902, a communication interface 903, and a memory 901. Optionally, device 900 may further include a communication line 904. The communication interface 903, the processor 902, and the memory 901 may be connected to each other using the communication line 904. The communication line 904 may be a peripheral component interconnect (PCI) bus, an extended industry standard architecture (EISA) bus, etc. The communication line 904 may be classified into an address bus, a data bus, a control bus, etc. For ease of representation, only one thick line is used to represent buses in Figure 9, but this does not mean that there is only one bus or only one type of bus.

[0179] The processor 902 may be a CPU, microprocessor, ASIC, or one or more integrated circuits configured to control program execution in the solution of this application.

[0180] The communication interface 903 is any device, such as a transceiver, configured to communicate with other devices or communication networks such as Ethernet, a radio access network (RAN), a wireless local area network (WLAN), or a wired access network.

[0181] Memory 901 may be ROM, other types of static storage devices capable of storing static information and instructions, RAM, or other types of dynamic storage devices capable of storing information and instructions; or it may be electrically erasable programmable read-only memory (EEPROM), compact disc read-only memory (CD-ROM), or other compact disc storage, optical disc storage (including compact discs, laser discs, optical discs, digital multipurpose discs, Blu-ray discs, etc.), magnetic disk storage media, or other magnetic storage devices; or any other medium that can be configured to carry or store expected program code in the form of instructions or data structures that can be accessed by a computer. However, memory 901 is not limited to these. Memory may exist independently or be connected to the processor via a communication line 904. Alternatively, memory may be integrated with the processor.

[0182] Memory 901 is configured to store computer-executable instructions for executing the solution in this application, and processor 902 controls the execution. Processor 902 is configured to execute the computer-executable instructions stored in memory 901 to implement the data transmission method provided in the aforementioned embodiments of this application.

[0183] Optionally, the computer executable instructions in the embodiments of this application may also be called application program code. This is not particularly limited in the embodiments of this application.

[0184] Please refer to Figure 10. Embodiments of this application further provide other communication devices 1000, which are chip systems and include an input / output interface 1010 and logic circuits 1020.

[0185] When the communication device 1000 is a chip system in a terminal device, in some embodiments of this application, the logic circuit 1020 and the input / output interface 1010 may be configured to perform functions, operations, etc., performed by the terminal device. For example, the input / output interface 1010 is configured to input first multicast data utilizing multicast-based semi-persistent scheduling SPS transmission. The input / output interface 1010 is further configured to input first downlink control information DCI, the first DCI, which is scrambled by a configuration scheduling radio network temporary identifier CS-RNTI. The logic circuit 1020 is configured to receive first data through the input / output interface 1010 based on the first DCI, the first data being retransmitted data of the first multicast data. Optionally, before the first DCI is input through the input / output interface 1010, the logic circuit 1020 is further configured to determine that the reception of the first multicast data has failed and to output feedback information such as NACK, which indicates that the reception of the first multicast data has failed.

[0186] When the communication device 1000 is a chip system in a network device, in some embodiments of this application, the logic circuit 1020 and the input / output interface 1010 may be configured to perform functions or operations performed by the network device. The logic circuit 1020 is configured to generate first multicast data. The input / output interface 1010 is configured to output first multicast data, which utilizes multicast-based semi-persistent scheduling SPS transmission. The input / output interface 1010 is further configured to output first downlink control information DCI, which is scrambled by a configuration scheduling radio network temporary identifier CS-RNTI, which is used to schedule first data, which is retransmitted data of the first multicast data.

[0187] The communication device 1000 provided in this embodiment may be used in a terminal device to perform the method performed by the aforementioned terminal device, or in a network device to perform the method performed by the aforementioned network device. Therefore, for technical effects that can be achieved by a computer-readable storage medium, please refer to the method embodiment described above. Details will not be described again here.

[0188] Based on the embodiments described above, embodiments of this application further provide a communication system. The communication system includes at least one communication device used in a network device and at least one communication device used in a terminal device. For technical effects that can be achieved, please refer to the method embodiments described above. Details will not be described again here.

[0189] Based on the embodiments described above, embodiments of the present application further provide a computer-readable storage medium. The computer-readable storage medium stores a computer program or instruction. When an instruction is executed, a method executed by a network device in any of the embodiments described above is implemented, or a method executed by a data transmission device in any of the embodiments described above is implemented, or a method executed by a terminal device in any of the embodiments described above is implemented. The computer-readable storage medium may include any medium capable of storing program code, such as a USB flash drive, a removable hard disk, a read-only memory, a random access memory, a magnetic disk, or an optical disk.

[0190] To implement the functions of the communication device in Figures 9 and 10, embodiments of the present application further provide a chip including a processor configured to support the communication device when implementing the functions of the network device or terminal device in the method embodiments described above. In possible designs, the chip is connected to memory, or the chip includes memory, which is configured to store computer programs or instructions and data required by the communication device.

[0191] This application describes flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of this application. It can be understood that computer programs or instructions may be used to perform each step and / or block in the flowcharts and / or block diagrams, and combinations of steps and / or blocks in the flowcharts and / or block diagrams. These computer program instructions may be provided to a processor of a general-purpose computer, a dedicated computer, an embedded processor, or any other programmable data processing device for generating a machine, thereby the instructions executed by the computer or any other programmable data processing device processor generate a device for performing a particular function in one or more processes in the flowchart and / or one or more blocks in the block diagram.

[0192] Those skilled in the art will understand that embodiments of this application may be provided as methods, systems, or computer program products. All or part of the embodiments described above may be implemented using software, hardware, firmware, or any combination thereof. When software is used to implement an embodiment, the embodiment may be implemented in whole or in part as a computer program product. A computer program product includes one or more computer instructions. When the computer program instructions are loaded onto a computer and executed, all or part of the procedures or functions according to the embodiments of this application are generated. The computer may be a general-purpose computer, a dedicated computer, a computer network, or other programmable device. Computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center by wire (e.g., coaxial cable, optical fiber, or digital subscriber line (DSL)) or wirelessly (e.g., infrared, radio waves, or microwaves). Computer-readable storage media can be any available medium accessible by a computer, or a data storage device that integrates one or more available media, such as a server or data center. Available media can be magnetic media (e.g., floppy disks, hard disks, or magnetic tapes), optical media (e.g., DVDs), or semiconductor media (e.g., solid-state drives (SSDs)).

[0193] The various exemplary logic units and circuits described in embodiments of this application may perform or operate the described functions using designs of general-purpose processors, digital signal processors, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs) or other programmable logic devices, discrete gate or transistor logic, discrete hardware components, or any combination thereof. The general-purpose processor may be a microprocessor. Optionally, the general-purpose processor may be any conventional processor, controller, microcontroller, or state machine. The processor may be implemented by a combination of computing devices, such as a digital signal processor and a microprocessor, multiple microprocessors, one or more microprocessors with digital signal processor cores, or any other similar configuration.

[0194] Steps of the methods or algorithms described in embodiments of this application may be directly incorporated into hardware, software units executed by a processor, or a combination thereof. The software units may be stored in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disks, removable magnetic disks, CD-ROMs, or any other form of storage medium in the art. For example, the storage medium may be connected to a processor, thereby enabling the processor to read information from and write information to the storage medium. Optionally, the storage medium may be integrated into the processor. The processor and storage medium may be located in an ASIC.

[0195] These computer program instructions can, alternatively, be loaded onto a computer or other programmable data processing device, thereby executing a series of operations and steps on the computer or other programmable device, and thereby generating computer execution processing. Therefore, the instructions executed on the computer or other programmable device provide steps for performing a specific function in one or more steps in a flowchart and / or in one or more blocks in a block diagram.

[0196] This application is described in relation to certain features and embodiments thereof, but it is clear that various modifications and combinations can be made to them without departing from the ideas and scope of this application. Accordingly, this specification and the accompanying drawings are merely exemplary descriptions of this application as defined by the accompanying claims and should be considered as any or all of the modifications, variations, combinations, or equivalents that cover the scope of this application. It is clear to those skilled in the art that various modifications and variations can be made to this application without departing from the scope of this application. Therefore, this application is intended to cover these modifications and variations of this application as far as they fall within the scope of the claims and their equivalent art.

Claims

1. The steps include receiving second downlink control information (DCI) scrambled by a Group Radio Network Temporary Identifier (G-RNTI), wherein the second DCI is used to activate multicast-based semi-persistent scheduling (SPS) transmissions; The steps include receiving first multicast data using the multicast-based semi-persistent scheduling (SPS) transmission, The steps include receiving a first DCI, wherein the first DCI is scrambled by a configuration scheduling radio network temporary identifier (CS-RNTI), and the CS-RNTI identifies a unicast transmission, A step of receiving first data based on the first DCI, wherein the first data is a retransmission of the first multicast data, and the first data is transmitted in unicast mode. A data transmission method comprising the following features.

2. The value of the first indication information included in the second DCI is a first value, and the value of the first indication information includes the first value or the second value, the first value indicates multicast-based semi-persistent scheduling (SPS) transmission, and the second value indicates multicast-based dynamic scheduling transmission. The method according to claim 1.

3. The second DCI includes SPS configuration information indicating an SPS configuration corresponding to the activated multicast-based SPS transmission, and the second DCI is not interpreted as including information indicating that the second DCI is used to schedule uplink or downlink transmissions based on the SPS configuration information. The method according to claim 2.

4. The new data indicator (NDI) value in the first DCI is 1, and the new data indicator (NDI) value in the second DCI is 0. The method according to claim 1.

5. The new data indicator (NDI) value in the first DCI is 1, and the new data indicator (NDI) value in the second DCI is 0. The method according to claim 2 or 3.

6. Steps include receiving a third DCI scrambled by a Group Configuration Scheduling Radio Network Temporary Identifier (G-CS-RNTI), wherein the third DCI is used to deactivate the multicast-based semi-persistent scheduling (SPS) transmission, The method according to any one of claims 1 to 5, further comprising:

7. The steps include transmitting a second downlink control information (DCI) scrambled by a Group Radio Network Temporary Identifier (G-RNTI), wherein the second DCI is used to activate multicast-based semi-persistent scheduling (SPS) transmissions; The steps include transmitting first multicast data using the multicast-based semi-persistent scheduling (SPS) transmission, A step of transmitting a first DCI, wherein the first DCI is scrambled by a Configuration Scheduling Radio Network Temporary Identifier (CS-RNTI), the CS-RNTI identifies a unicast transmission, the first DCI is used to schedule first data, the first data is a retransmission of the first multicast data, and the first data is transmitted in unicast mode. A data transmission method comprising the following features.

8. The value of the first indication information included in the second DCI is a first value, and the value of the first indication information includes the first value or the second value, the first value indicates multicast-based semi-persistent scheduling (SPS) transmission, and the second value indicates multicast-based dynamic scheduling transmission. The method according to claim 7.

9. The second DCI includes SPS configuration information indicating an SPS configuration corresponding to the activated multicast-based SPS transmission, and the second DCI is not interpreted as including information indicating that the second DCI is used to schedule uplink or downlink transmissions based on the SPS configuration information. The method according to claim 8.

10. The new data indicator (NDI) value in the first DCI is 1, and the new data indicator (NDI) value in the second DCI is 0. The method according to claim 7.

11. The new data indicator (NDI) value in the first DCI is 1, and the new data indicator (NDI) value in the second DCI is 0. The method according to claim 8 or 9.

12. A step of transmitting a third DCI scrambled by a Group Configuration Scheduling Radio Network Temporary Identifier (G-CS-RNTI), wherein the third DCI is used to deactivate the multicast-based semi-persistent scheduling (SPS) transmission. The method according to any one of claims 7 to 11, further comprising:

13. A communication unit, Receiving second downlink control information (DCI) scrambled by a Group Radio Network Temporary Identifier (G-RNTI), wherein the second DCI is used to activate multicast-based semi-persistent scheduling (SPS) transmissions. Receiving first multicast data using the multicast-based semi-persistent scheduling (SPS) transmission, Receiving a first DCI, wherein the first DCI is scrambled by a Configuration Scheduling Radio Network Temporary Identifier (CS-RNTI), and the CS-RNTI identifies a unicast transmission. A communication unit configured to perform the following: A processing unit configured to receive first data based on the first DCI through the communication unit, wherein the first data is a retransmission of the first multicast data, and the first data is transmitted in unicast mode, and Equipped with, Data transmission device.

14. The value of the first indication information included in the second DCI is a first value, and the value of the first indication information includes the first value or the second value, the first value indicates multicast-based semi-persistent scheduling (SPS) transmission, and the second value indicates multicast-based dynamic scheduling transmission. The apparatus according to claim 13.

15. The second DCI includes SPS configuration information indicating an SPS configuration corresponding to the activated multicast-based SPS transmission, and the second DCI is not interpreted as including information indicating that the second DCI is used to schedule uplink or downlink transmissions based on the SPS configuration information. The apparatus according to claim 14.

16. The new data indicator (NDI) value in the first DCI is 1, and the new data indicator (NDI) value in the second DCI is 0. The apparatus according to claim 13.

17. The new data indicator (NDI) value in the first DCI is 1, and the new data indicator (NDI) value in the second DCI is 0. The apparatus according to claim 14 or 15.

18. The aforementioned communication unit is Receiving a third DCI scrambled by a Group Configuration Scheduling Radio Network Temporary Identifier (G-CS-RNTI), wherein the third DCI is used to deactivate the multicast-based semi-persistent scheduling (SPS) transmission. The apparatus according to any one of claims 13 to 17, further configured to perform the following:

19. A communication unit, Transmitting a second downlink control information (DCI) scrambled by a Group Radio Network Temporary Identifier (G-RNTI), wherein the second DCI is used to activate multicast-based semi-persistent scheduling (SPS) transmissions. A communication unit configured to perform the following: A processing unit configured to generate first multicast data utilizing the multicast-based semi-persistent scheduling (SPS) transmission, A data transmission device comprising, The aforementioned communication unit is Transmitting the first multicast data, The method involves transmitting a first DCI, the first DCI being scrambled by a Configuration Scheduling Radio Network Temporary Identifier (CS-RNTI), the CS-RNTI identifying a unicast transmission, the first DCI being used to schedule first data, the first data being a retransmission of the first multicast data, and the first data being transmitted in unicast mode. Further configured to perform, Data transmission device.

20. The value of the first indication information included in the second DCI is a first value, and the value of the first indication information includes the first value or the second value, the first value indicates multicast-based semi-persistent scheduling (SPS) transmission, and the second value indicates multicast-based dynamic scheduling transmission. The apparatus according to claim 19.

21. The second DCI includes SPS configuration information indicating an SPS configuration corresponding to the activated multicast-based SPS transmission, and the second DCI is not interpreted as including information indicating that the second DCI is used to schedule uplink or downlink transmissions based on the SPS configuration information. The apparatus according to claim 20.

22. The new data indicator (NDI) value in the first DCI is 1, and the new data indicator (NDI) value in the second DCI is 0. The apparatus according to claim 19.

23. The new data indicator (NDI) value in the first DCI is 1, and the new data indicator (NDI) value in the second DCI is 0. The apparatus according to claim 20 or 21.

24. The aforementioned communication unit is Transmitting a third DCI scrambled by a Group Configuration Scheduling Radio Network Temporary Identifier (G-CS-RNTI), wherein the third DCI is used to deactivate the multicast-based semi-persistent scheduling (SPS) transmission. The apparatus according to any one of claims 19 to 23, further configured to perform the following:

25. A communication device including a processor, wherein the processor is coupled to a memory, the memory is configured to store a computer program or instructions, and the processor is configured to execute the computer program or instructions to carry out the method according to any one of claims 1 to 6 or any one of claims 7 to 12. Communication device.

26. A computer-readable storage medium storing a computer program or instruction, wherein when the instruction is executed on a computer, the method according to any one of claims 1 to 6 or the method according to any one of claims 7 to 12 is performed. Computer-readable storage medium.

27. A computer program including a computer instruction, wherein when the computer instruction is executed on a computer, the computer becomes capable of carrying out the method according to any one of claims 1 to 6 or the method according to any one of claims 7 to 12. Computer program.

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