A communication method and apparatus

Abstract

The application discloses a communication method and device, wherein the method comprises: a terminal device receives first information from a network device, the first information is used to indicate that the terminal device acquires multicast configuration information through a system message, and the multicast configuration information is used to indicate that the terminal device receives multicast service; and then the terminal device receives the system message from the network device, and the system message comprises the multicast configuration information. By using the scheme, on one hand, the terminal device can receive multicast service without entering a connected state, thereby effectively reducing signaling overhead required for RRC connection establishment of the terminal device and the network device, and reducing the time delay of the terminal device for acquiring multicast configuration; on the other hand, since the network device can send multicast configuration information through a system message, compared with sending multicast configuration information to the terminal device through a unicast mode respectively, the processing burden and signaling overhead of the network device are effectively reduced, and the flexibility of network device regulation and control is increased.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wireless communication, and particularly relates to a communication method and device. BACKGROUND

[0002] In a wireless communication system, a multicast transmission technology is a transmission technology in which one sender transmits data and multiple receivers receive the data; for example, a network device transmits data and multiple terminal devices receive the data. One possible multicast transmission technology is a single cell point to multipoint (SC-PTM) technology.

[0003] When the multicast transmission technology (such as the SC-PTM technology) is used to transmit multicast service, a terminal device needs to first acquire multicast configuration information, and then receive the multicast service based on the multicast configuration information.

[0004] However, how the terminal device acquires the multicast configuration information still needs further research. SUMMARY

[0005] The present application provides a communication method and device, which reduces the signaling overhead of a terminal device in an idle state or an inactive state acquiring multicast configuration information.

[0006] In a first aspect, an embodiment of the present application provides a communication method, which can be applied to a terminal device, or can also be applied to a chip inside the terminal device. Taking the case where the method is applied to a terminal device, in the method, the terminal device receives first information from a network device, the first information being used to instruct the terminal device to acquire multicast configuration information through a system message, the multicast configuration information being used to instruct the terminal device to receive multicast service; and then receives the system message from the network device, the system message including the multicast configuration information.

[0007] By using this scheme, on the one hand, the terminal device does not need to enter a connected state, thereby effectively reducing the signaling overhead required for the terminal device and the network device to establish an RRC connection, and also reducing the latency of the terminal device acquiring the multicast configuration; on the other hand, since the network device can send the multicast configuration information through the system message, compared with sending the multicast configuration information to the terminal device through a unicast manner respectively, the processing burden and the signaling overhead of the network device are effectively reduced, and the flexibility of the network device in regulation and control is also increased.

[0008] In a possible design, the terminal device is in an RRC idle state or an RRC inactive state.

[0009] In a possible design, the multicast configuration information includes a G-RNTI associated with the multicast service and an identifier of the multicast service.

[0010] In one possible design, the first information is carried in a paging message from the network device.

[0011] In this way, since the first information is carried in the paging message, there is no need to send the first information separately, which can effectively save transmission resources.

[0012] In one possible design, the paging message includes a paging record list, and the paging record list does not include an identifier of the terminal device.

[0013] In this way, since the paging record list may not include the identifier of the terminal device, the resource overhead of the paging message can be effectively saved.

[0014] In one possible design, the first information includes an identifier of the multicast service.

[0015] In one possible design, the first information is carried in first downlink control information from the network device, and the first downlink control information is used to schedule paging messages.

[0016] In this way, since the first information is carried in the first downlink control information, there is no need to send the first information separately, which can effectively save transmission resources.

[0017] In one possible design, the first information is first downlink control information from a network device, and the first downlink control information is used to schedule a paging message; wherein, the first downlink control information is encrypted by a first wireless network temporary identifier RNTI, and the first RNTI is different from the P-RNTI; or, the first downlink control information is transmitted through preset time-frequency resources.

[0018] In this way, the first downlink control information implicitly instructs the terminal device to obtain the multicast configuration information through the system message, which can effectively save transmission resources.

[0019] In one possible design, the first information is carried in a downlink message during a random access process performed by a terminal device; the downlink message is a contention resolution message; or the downlink message is second downlink control information, and the second downlink control information is used to schedule the contention resolution message.

[0020] In one possible design, the method further includes: the terminal device sending an identifier of the terminal device and / or an identifier of the multicast service to the network device during a random access process.

[0021] In one possible design, the terminal device receives the system message from the network device, including: the terminal device receives the system message from the network device in the same system message change period or the same frame or the same subframe or the same time slot or the same sub-time slot as the first information.

[0022] When the network device carries the multicast configuration information in the system message, it is equivalent to that the system message is changed. Generally, the network device needs to notify the terminal device that the current system message is changed through the system message change indication, and then the terminal device receiving the system message change indication reacquires the system message in the next system message change period. In the embodiment of the application, the network device can send the first information to the terminal device. Correspondingly, the terminal device can receive the system message from the network device in the same system message change period or the same frame or the same subframe or the same time slot or the same sub-time slot of the first information after receiving the first information, that is, the terminal device can receive the system message without depending on the system message change indication, so that the terminal device can acquire the multicast configuration information more timely.

[0023] In a second aspect, the embodiment of the application provides a communication method, which can be applied to a network device or a chip inside the network device. Taking the case that the method is applied to the network device, in the method, the network device can send first information, the first information being used to instruct a terminal device to acquire multicast configuration information through a system message, the multicast configuration information being used to instruct the terminal device to receive a multicast service; and send the system message, the system message including the multicast configuration information.

[0024] Since the communication method described in the second aspect corresponds to the communication method described in the first aspect, the beneficial effects of the communication method described in the second aspect can be referred to the first aspect, which will not be repeated here.

[0025] In a possible design, the terminal device is in an RRC idle state or an RRC inactive state.

[0026] In a possible design, the multicast configuration information includes a G-RNTI associated with the multicast service and an identifier of the multicast service.

[0027] In a possible design, the first information is carried in a paging message.

[0028] In a possible design, the paging message includes a paging record list, and the paging record list does not include an identifier of the terminal device.

[0029] In a possible design, the first information includes an identifier of the multicast service.

[0030] In a possible design, the first information is carried in first downlink control information, and the first downlink control information is used to schedule the paging message.

[0031] In a possible design, the first information is first downlink control information, and the first downlink control information is used for scheduling a paging message; wherein the first downlink control information is scrambled by a first radio network temporary identifier (RNTI), and the first RNTI is different from a paging RNTI (P-RNTI); or the first downlink control information is carried on preset time-frequency resources.

[0032] In a possible design, the first information is carried in a downlink message in a random access procedure performed by the terminal device; wherein the downlink message is a contention resolution message; or the downlink message is second downlink control information, and the second downlink control information is used for scheduling the contention resolution message.

[0033] In a possible design, before the first information is sent, the method further includes: receiving an identifier of the terminal device and / or an identifier of the multicast service sent by the terminal device; and determining, according to the identifier of the terminal device and / or the identifier of the multicast service, that the terminal device needs to acquire the multicast configuration information.

[0034] In a possible design, before the first information is sent, the method further includes: determining that a number of RRC connections of the network device is greater than a first threshold.

[0035] In a third aspect, a communication apparatus is provided. The communication apparatus can be a terminal device or a chip arranged in a terminal device. The communication apparatus has the functions of the first aspect, for example, the communication apparatus includes modules or units or means corresponding to the steps of the first aspect. The functions or units or means can be implemented by software or hardware, or by a combination of hardware and software.

[0036] In a possible design, the communication apparatus includes a processing unit and a communication unit. The communication unit can be configured to transceive signals to implement communication between the communication apparatus and other apparatuses, for example, the communication unit is configured to receive the first information from the network device. The processing unit can be configured to perform some internal operations of the communication apparatus. The functions performed by the processing unit and the communication unit can correspond to the steps of the first aspect.

[0037] In a possible design of the communication apparatus, the communication apparatus includes a processor, and can further include a transceiver configured to transceive signals, and the processor is configured to execute program instructions to implement the method in any possible design or implementation manner of the first aspect. The communication apparatus can further include one or more memories coupled to the processor. The one or more memories can be integrated with the processor, or can be separately arranged from the processor, which is not limited in the present application. The memories can store necessary computer programs or instructions for implementing the functions in the first aspect. The processor can execute the computer programs or instructions stored in the memories, and when the computer programs or instructions are executed, the communication apparatus can implement the method in any possible design or implementation manner of the first aspect.

[0038] In a possible design of the communication apparatus, the communication apparatus includes a processor and a memory, and the memory can store necessary computer programs or instructions for implementing the functions in the first aspect. The processor can execute the computer programs or instructions stored in the memories, and when the computer programs or instructions are executed, the communication apparatus can implement the method in any possible design or implementation manner of the first aspect.

[0039] In a possible design of the communication apparatus, the communication apparatus includes at least one processor and an interface circuit, and the at least one processor is configured to communicate with other apparatuses through the interface circuit, and implement the method executed by the terminal device in any possible design or implementation manner of the first aspect.

[0040] In a fourth aspect, the present application provides a communication apparatus, which can be a network device or a chip arranged in the network device. The communication apparatus has the functions in the second aspect, for example, the communication apparatus includes modules or units or means corresponding to the steps in the second aspect, and the functions or units or means can be implemented by software or hardware, or by executing corresponding software by hardware.

[0041] In a possible design of the communication apparatus, the communication apparatus includes a processor, and can further include a transceiver configured to transceive signals, and the processor is configured to execute program instructions to implement the method in any possible design or implementation manner of the first aspect. The communication apparatus can further include one or more memories coupled to the processor. The one or more memories can be integrated with the processor, or can be separately arranged from the processor, which is not limited in the present application. The memories can store necessary computer programs or instructions for implementing the functions in the first aspect. The processor can execute the computer programs or instructions stored in the memories, and when the computer programs or instructions are executed, the communication apparatus can implement the method in any possible design or implementation manner of the first aspect.

[0042] In a possible design, the communication apparatus includes a processor, and can further include a transceiver configured to transceive signals, and the processor is configured to execute program instructions to complete the method in any possible design or implementation manner of the second aspect. The communication apparatus can further include one or more memories coupled to the processor. The one or more memories can be integrated with the processor, or can be separately arranged, which is not limited in the application. The memories can store necessary computer programs or instructions for implementing the functions in the second aspect. The processor can execute the computer programs or instructions stored in the memories, and when the computer programs or instructions are executed, the communication apparatus can implement the method in any possible design or implementation manner of the second aspect.

[0043] In a possible design, the communication apparatus includes a processor and a memory, and the memory can store necessary computer programs or instructions for implementing the functions in the second aspect. The processor can execute the computer programs or instructions stored in the memory, and when the computer programs or instructions are executed, the communication apparatus can implement the method in any possible design or implementation manner of the second aspect.

[0044] In a possible design, the communication apparatus includes at least one processor and an interface circuit, and the at least one processor is configured to communicate with other apparatuses through the interface circuit, and execute the method in any possible design or implementation manner of the second aspect.

[0045] In a fifth aspect, the application provides a computer readable storage medium, and the computer readable storage medium stores computer readable instructions, and when a computer reads and executes the computer readable instructions, the computer executes the method in any possible design of the first aspect or the second aspect.

[0046] In a sixth aspect, the application provides a computer program product, and when a computer reads and executes the computer program product, the computer executes the method in any possible design of the first aspect or the second aspect.

[0047] In a seventh aspect, the application provides a chip, and the chip includes a processor coupled to a memory, and the processor is configured to read and execute a software program stored in the memory, to implement the method in any possible design of the first aspect or the second aspect.

[0048] These aspects or other aspects of the application will be more apparent in the following description of the embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0049] Figure 1 A network architecture diagram suitable for the embodiments of the application;

[0050] Figure 2 Another network architecture diagram applicable to embodiments of the present application;

[0051] Figure 3 Another network architecture diagram applicable to embodiments of the present application;

[0052] Figure 4a A diagram of multicast service transmission by a network device;

[0053] Figure 4b A diagram of multicast configuration information acquisition by a terminal device;

[0054] Figure 5 Another diagram of multicast configuration information acquisition by a plurality of terminal devices in an idle state or an inactive state;

[0055] Figure 6a A diagram of a four-step random access procedure provided by embodiments of the present application;

[0056] Figure 6b A diagram of a two-step random access procedure provided by embodiments of the present application;

[0057] Figure 6c A diagram of a paging frame and a paging occasion in a paging cycle provided by embodiments of the present application;

[0058] Figure 6d A diagram of slots included in a PO provided by embodiments of the present application;

[0059] Figure 6e A diagram of SC-MCCH and SC-MTCH provided by embodiments of the present application;

[0060] Figure 6f A diagram of a repetition period and a modification period of SC-MCCH provided by embodiments of the present application;

[0061] Figure 7a A diagram of a flow corresponding to a communication method provided by Embodiment One of the present application;

[0062] Figure 7b A diagram of a system message periodically transmitted by a network device provided by embodiments of the present application;

[0063] Figure 8a A diagram of a flow corresponding to a communication method provided by Embodiment Two of the present application;

[0064] Figure 8b Another diagram of multicast configuration information acquisition by a plurality of terminal devices in an idle state or an inactive state;

[0065] Figure 9a A flowchart corresponding to the communication method provided in Embodiment Four of the present application;

[0066] Figure 9b Another example diagram for acquiring multicast configuration information for a plurality of terminal devices in an idle state or an inactive state;

[0067] Figure 10 A possible example block diagram of the apparatus involved in the embodiments of the present application;

[0068] Figure 11 A structural diagram of a terminal device provided in the embodiments of the present application;

[0069] Figure 12 A structural diagram of a network device provided in the embodiments of the present application. DETAILED DESCRIPTION

[0070] The technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application.

[0071] First, some terms in the embodiments of the present application are explained and described to facilitate understanding by those skilled in the art.

[0072] (1) Terminal device: can be a wireless terminal device capable of receiving network device scheduling and indication information, the wireless terminal device can be a device that provides voice and / or data connectivity to a user, or a handheld device with a wireless connection function, or other processing devices connected to a wireless modem. The terminal device can communicate with one or more core networks or the Internet through a radio access network (RAN), and the terminal device can be a mobile terminal device, such as a mobile phone (or called "cellular" phone, mobile phone), computer and data card, for example, can be portable, pocket-sized, handheld, computer built-in or vehicle-mounted mobile devices that exchange voice and / or data with the radio access network. For example, personal communication service (PCS) phones, cordless phones, session initiation protocol (SIP) phones, wireless local loop (WLL) stations, personal digital assistants (PDAs), tablets (Pads), computers with wireless transceiver functions, etc. The wireless terminal device can also be referred to as a system, subscriber unit, subscriber station, mobile station, mobile station (MS), remote station, access point (AP), remote terminal, access terminal, user terminal, user agent, subscriber station (SS), customer premises equipment (CPE), terminal, user equipment (UE), mobile terminal (MT), etc. The terminal device can also be a wearable device and a next-generation communication system, such as a terminal device in a 5G communication system or a terminal device in a future evolved public land mobile network (PLMN), etc.

[0073] (2) Network device: can be a device in a wireless network, for example, the network device can be a radio access network (RAN) node (or device) that accesses a terminal device to a wireless network, which can also be referred to as a base station. At present, some examples of RAN devices are: a new generation base station (gNodeB) in a 5G communication system, a transmission reception point (TRP), an evolved Node B (eNB), a radio network controller (RNC), a Node B (NB), a base station controller (BSC), a base transceiver station (BTS), a home base station (for example, a home evolved NodeB or a home Node B, HNB), a baseband unit (BBU), or a wireless fidelity (Wi-Fi) access point (AP), etc. In addition, in a network structure, the network device can include a centralized unit (CU) node, or a distributed unit (DU) node, or a RAN device including a CU node and a DU node. In addition, in other possible cases, the network device can be other apparatuses that provide wireless communication functions for terminal devices. The embodiments of the present application do not limit the specific technology and specific device form of the network device. For convenience of description, the apparatuses that provide wireless communication functions for terminal devices are referred to as network devices in the embodiments of the present application.

[0074] (3) Working state of terminal device: the working state of the terminal device can include a radio resource control (RRC) idle (RRC_IDLE) state, an RRC inactive (Inactive) state and an RRC connected (RRC_CONNECTED) state. Among them, the RRC idle state can be referred to as idle state, the RRC inactive state can be referred to as inactive state, and the RRC connected state can be referred to as connected state. The three working states are described below.

[0075] Idle state: after the terminal device accesses the network device through the initial random access process, the network device can store the device parameters of the terminal device, and if the terminal device does not communicate with the network device for a long time, the network device deletes the stored device parameters of the terminal device, and at this time, the state of the terminal device is idle state. When in idle state, the terminal device does not have RRC connection, can perform cell selection and reselection, listen to the paging channel, and perform tracking area update (TAU). If the terminal device in idle state needs to communicate with the network device, it needs to initiate the random access process again.

[0076] Connected state: after the terminal device accesses the network device through the initial random access process, the network device can store the device parameters of the terminal device, and during this period, the terminal device can communicate with the network device, and at this time, the state of the terminal device is connected state. When in connected state, the terminal device can transmit and receive dedicated data, and according to the activity of the terminal device, it can save air interface resources and terminal device power through discontinuous reception (DRX).

[0077] Inactive state: the terminal device in inactive state is disconnected from the network device in RRC connection, and does not need to continuously listen to downlink data, thereby achieving the same power saving effect as idle state, but the terminal device in inactive state and the network device both save the context information of the terminal device, and when the terminal device needs to enter connected state, the network device can configure the terminal device in inactive state to enter connected state based on the saved context information.

[0078] (4) The terms "system" and "network" in the embodiments of the present application can be used interchangeably. "At least one" means one or more, and "multiple" means two or more. "And / or" describes the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which means that A exists alone, A and B exist together, and B exists alone, where A and B can be singular or plural. The character " / " generally represents an "or" relationship between the associated objects. "At least one of the following" or similar expressions means any combination of these items, including single item or any combination of multiple items. For example, "at least one of A, B and C" includes A, B, C, AB, AC, BC or ABC.

[0079] In addition, unless otherwise specified, the ordinal numbers "first", "second", etc. mentioned in the embodiments of the present application are used to distinguish multiple objects, and are not used to limit the order, time sequence, priority or importance of the multiple objects. For example, the first threshold and the second threshold are only used to distinguish different thresholds, and do not mean that the priority or importance of the two thresholds is different.

[0080] The technical solution of the present application is described in further detail below in conjunction with the accompanying drawings.

[0081] Figure 1 This is a schematic diagram of a network architecture applicable to the embodiment of this application. Figure 1 As shown, the terminal device 130 can access the wireless network to obtain services of the external network (such as the Internet) through the wireless network, or communicate with other devices through the wireless network, such as communicating with other terminal devices. The wireless network includes a radio access network (RAN) device 110 and a core network (CN) device 120, wherein the RAN device 110 is used to access the terminal device 130 to the wireless network, and the CN device 120 is used to manage the terminal device and provide a gateway for communicating with the external network. It should be understood that Figure 1 The number of devices in the communication system shown is for illustration only, and the embodiments of the present application are not limited thereto. In actual applications, the communication system may further include more terminal devices 130 , more RAN devices 110 , and other devices.

[0082] A CN may include multiple CN devices 120. Figure 1 When the network architecture shown is applicable to a 5G communication system, the CN device 120 may be an access and mobility management function (AMF) entity, a session management function (SMF) entity, or a user plane function (UPF) entity. Figure 1 When the network architecture shown is applicable to an LTE communication system, the CN device 120 may be a mobility management entity (MME) and a serving gateway (S-GW).

[0083] Figure 2 This is another network architecture diagram applicable to the embodiment of this application. Figure 2As shown, the network architecture includes a CN device, a RAN device and a terminal device. Among them, the RAN device includes a baseband device and a radio frequency device, wherein the baseband device can be implemented by one node, or can be implemented by multiple nodes, and the radio frequency device can be independently implemented by pulling away from the baseband device, or can be integrated in the baseband device, or part of the function is independently integrated, and part of the function is integrated in the baseband device. For example, in the LTE communication system, the RAN device (eNB) includes a baseband device and a radio frequency device, wherein the radio frequency device can be arranged remotely relative to the baseband device, for example, the remote radio unit (RRU) is a remote wireless unit arranged relative to the BBU.

[0084] The communication between the RAN device and the terminal device follows a certain protocol layer structure, for example, the control plane protocol layer structure can include the functions of the radio resource control (RRC) layer, the packet data convergence protocol (PDCP) layer, the radio link control (RLC) layer, the media access control (MAC) layer and the physical layer, etc. The user plane protocol layer structure can include the functions of the PDCP layer, the RLC layer, the MAC layer and the physical layer, etc. In one possible implementation, the PDCP layer can further include the service data adaptation (SDAP) layer.

[0085] The RAN device can implement the functions of the RRC, PDCP, RLC and MAC protocol layers by one node, or can implement the functions of these protocol layers by multiple nodes. For example, in one evolution structure, the RAN device can include a CU and a DU, and multiple DUs can be centrally controlled by one CU. As shown, Figure 2 As shown, the CU and the DU can be divided according to the protocol layers of the wireless network, for example, the functions of the PDCP layer and above protocol layers are set in the CU, and the functions of the protocol layers below PDCP, such as RLC layer and MAC layer, etc. are set in the DU.

[0086] The protocol layer division is only an example, and other protocol layer divisions are also possible, such as division at the RLC layer, with the functions of the RLC layer and the protocol layers above the RLC layer being arranged in the CU, and the functions of the protocol layers below the RLC layer being arranged in the DU; or division in a certain protocol layer, such as arranging part of the functions of the RLC layer and the functions of the protocol layers above the RLC layer in the CU, and arranging the remaining functions of the RLC layer and the functions of the protocol layers below the RLC layer in the DU. In addition, other divisions are also possible, such as division by delay, with the functions that need to meet a delay requirement in terms of processing time being arranged in the DU, and the functions that do not need to meet the delay requirement being arranged in the CU.

[0087] In addition, the radio frequency device can be independently integrated, not placed in the DU, or integrated in the DU, or partially remote and partially integrated in the DU, without any limitation here.

[0088] Figure 3 Another network architecture applicable to the embodiments of the present application is shown in the figure. Relative to the network architecture shown in Figure 2 , Figure 3 The control plane (CP) and the user plane (UP) of the CU can also be separated and implemented as different entities, namely a control plane (control plane, CP) CU entity (namely a CU-CP entity) and a user plane (user plane, UP) CU entity (namely a CU-UP entity).

[0089] In the above network architecture, the signaling generated by the CU can be transmitted to the terminal device through the DU, or the signaling generated by the terminal device can be transmitted to the CU through the DU. The DU can directly transmit the signaling to the terminal device or the CU through protocol layer encapsulation without parsing the signaling. In the following embodiments, if the transmission of such signaling between the DU and the terminal device is involved, the transmission or reception of the signaling by the DU includes this scenario. For example, the signaling of the RRC or PDCP layer will eventually be processed as the signaling of the PHY layer transmitted to the terminal device, or converted from the received PHY layer signaling. In this architecture, the signaling of the RRC or PDCP layer can also be considered as being transmitted by the DU, or transmitted by the DU and the radio frequency device.

[0090] The above Figure 1 , Figure 2 or Figure 3The network architecture shown can be applied to a communication system of various radio access technologies (RATs), for example, can be an LTE communication system, can also be a 5G (or referred to as new radio (NR)) communication system, can also be a transition system between the LTE communication system and the 5G communication system, which can also be referred to as a 4.5G communication system, and of course can also be a future communication system. The network architecture and service scenarios described in the embodiments of the present application are for more clearly illustrating the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided by the embodiments of the present application. Those skilled in the art can know that, with the evolution of the communication network architecture and the appearance of new service scenarios, the technical solutions provided by the embodiments of the present application are also applicable to similar technical problems.

[0091] The device in the following embodiments of the present application can be located in a terminal device or a network device according to the function implemented. When the above CU-DU structure is adopted, the network device can be a CU node, or a DU node, or a RAN device including a CU node and a DU node.

[0092] In Figure 1 , Figure 2 or Figure 3 In the network architecture shown, the network device can transmit service data to the terminal device in a multicast manner, for example, the multicast transmission can be implemented by using the SC-PTM technology. In the SC-PTM technology, the multicast service can be transmitted by using the physical downlink shared channel (PDSCH). Different from the PDSCH carrying the unicast service, the PDSCH carrying the multicast service can be referred to as multicast PDSCH. The network device can send downlink control information (DCI) carrying on the physical downlink control channel (PDCCH) to a group of terminal devices in a cell, the DCI is used to schedule the multicast PDSCH carrying the multicast service, and the DCI can be scrambled by using the group-radio network temporary identity (G-RNTI) associated with the multicast service. After receiving the DCI, the group of terminal devices can receive the multicast PDSCH according to the scheduling information included in the DCI.

[0093] Referring to Figure 4aAs shown, the network device is shown in two multicast service transmission scenarios. The network device can allocate G-RNTI 1 for multicast service 1, and G-RNTI 2 for multicast service 2, that is, the G-RNTI associated with multicast service 1 is G-RNTI 1, and the G-RNTI associated with multicast service 2 is G-RNTI 2. In order to receive multicast service 1, the first group of terminal devices (such as including terminal device 1, terminal device 2 and terminal device 3) need to obtain the multicast configuration information of multicast service 1 (such as the multicast configuration information can include the G-RNTI 1 associated with multicast service 1), and receive the DCI 1 sent by the network device for scheduling the multicast PDSCH 1 (the multicast PDSCH 1 is used to carry the multicast service 1) according to the G-RNTI 1, and then receive the multicast PDSCH 1. Similarly, in order to receive multicast service 2, the second group of terminal devices (such as including terminal device 4, terminal device 5 and terminal device 6) need to obtain the multicast configuration information of multicast service 2.

[0094] For how the terminal device obtains the multicast configuration information, one possible implementation is that when the terminal device is in an idle state or an inactive state, the network device can page the terminal device, and then the terminal device can initiate a random access process and establish an RRC connection with the network device to enter a connected state after the random access process is successful, and then the network device can send the multicast configuration information of the multicast service to the terminal device in a unicast manner. The following describes in detail the process of obtaining the multicast configuration information by the terminal device in the idle state or the inactive state. Figure 4b For how the terminal device obtains the multicast configuration information, one possible implementation is that when the terminal device is in an idle state or an inactive state, the network device can page the terminal device, and then the terminal device can initiate a random access process and establish an RRC connection with the network device to enter a connected state after the random access process is successful, and then the network device can send the multicast configuration information of the multicast service to the terminal device in a unicast manner. The following describes in detail the process of obtaining the multicast configuration information by the terminal device in the idle state or the inactive state.

[0095] Figure 4b A flowchart for the terminal device to obtain the multicast configuration information of the multicast service is shown in FIG. 4, and the flowchart can include the following steps. Figure 4b As shown in FIG. 4, the flowchart can include the following steps.

[0096] In step 401, the terminal device 1 sends a request message to the core network device, and the request message is used to request a multicast service of interest to the terminal device 1, such as multicast service 1.

[0097] Here, the message can be a registration request message, an attachment request message, or a protocol data unit (PDU) session establishment request message or a PDU session modification message, or other possible non-access stratum (NAS) messages, which are not limited in specific.

[0098] In step 402, the core network device configures parameters for transmitting data of the multicast service 1 for the terminal device 1 according to the request message of the terminal device 1 after determining that the terminal device 1 is a legal device and the terminal device has the qualification to obtain the multicast service 1.

[0099] Further, the core network device can maintain a correspondence between the identifier of the terminal device 1 and the identifier of the multicast service of interest to the terminal device 1. The core network device can also inform one or more network devices of the identifier of the terminal device 1 and the identifier of the multicast service of interest to the terminal device 1, so that the one or more network devices can maintain a correspondence between the identifier of the terminal device 1 and the identifier of the multicast service of interest to the terminal device 1.

[0100] In step 403, the core network device receives data of the multicast service 1.

[0101] In step 404, the core network device sends paging indication information to one or more network devices, including the network device 1.

[0102] Here, after receiving the data of the multicast service 1, the core network device can obtain the identifiers of the terminal devices of interest to the multicast service 1 (such as the terminal device 1 and the terminal device 2) according to the correspondence between the identifiers of the terminal devices and the identifiers of the multicast services of interest to the terminal devices maintained by the core network device. Assuming that the terminal device 1 and the terminal device 2 are both located in the coverage of the network device 1, and the terminal device 1 is in an idle state and the terminal device 2 is in a connected state, the core network device can then generate paging indication information, which can include a list of identifiers of terminal devices that need to be paged (such as the identifier of the terminal device 1, and the identifier of the terminal device 2 can not be included because the terminal device 2 is in a connected state), so that the terminal devices paged enter a connected state.

[0103] For example, the core network device learns that the terminal device 2 is in a connected state and located in the coverage of the network device 1, and then transmits the data of the multicast service 1 to the network device 1, that is, the core network device learns the network device to which the terminal device of interest to the multicast service 1 is connected, and then transmits the data of the multicast service 1 to the network device. Accordingly, if the network device 1 determines to send the data of the multicast service 1 in a multicast manner, it can send the data of the multicast service 1 to the terminal devices of interest to the multicast service 1 (such as the terminal device 1 and the terminal device 2) in a multicast manner.

[0104] In step 405, the network device 1 receives the paging indication information and sends control information scheduling a paging message to the terminal device 1.

[0105] For example, the network device 1 determines the terminal device that needs to be paged, such as the terminal device 1, according to the paging indication information. Then, the network device 1 can determine the PO corresponding to the terminal device 1 according to the identifier of the terminal device 1, and then send control information on the PO corresponding to the terminal device 1.

[0106] Step 406, the terminal device 1 receives the control information.

[0107] Here, the terminal device 1 can determine the PO corresponding to the terminal device 1 according to the identifier of the terminal device, and then listen to the control information on the PO.

[0108] Step 407, the network device 1 sends a paging message on the resource indicated by the control information.

[0109] Step 408, after receiving the control information, the terminal device 1 receives the paging message on the resource indicated by the control information.

[0110] Step 409, the terminal device 1 determines that the RRC connection with the network device 1 needs to be established according to the paging message, and then initiates a random access process.

[0111] Here, the random access process can be a four-step random access process or a two-step random access process. The specific implementation of the four-step random access process and the two-step random access process can be referred to later. After the terminal device 1 initiates the random access process, if the random access is successful, the terminal device 1 can enter the RRC connected state.

[0112] Step 410, the network device 1 sends multicast configuration information to the terminal device 1 in the connected state.

[0113] Here, taking the multicast service 1 as an example, if the network device 1 determines to send the data of the multicast service 1 in a multicast manner, the network device 1 can allocate an associated G-RNTI for the multicast service 1; the multicast configuration information can include the G-RNTI associated with the multicast service 1.

[0114] Step 411, the terminal device 1 receives the multicast configuration information, and can subsequently receive the data of the multicast service 1 according to the G-RNTI associated with the multicast service 1.

[0115] Exemplarily, the network device 1 can also send the multicast configuration information to the terminal device 2 in the connected state, and subsequently the terminal device 2 can receive the data of the multicast service 1 according to the G-RNTI associated with the multicast service 1.

[0116] In the above manner, the terminal device in the idle state or the inactive state needs to enter the connected state first, and then the network device sends the multicast configuration information to the terminal device in a unicast manner, so that the signaling overhead required for the terminal device in the idle state or the inactive state to obtain the multicast configuration information is large. Especially when there are a large number of terminal devices in the idle state or the inactive state in the network, each terminal device needs to establish an RRC connection with the network device, and the network device needs to send the multicast configuration information to each terminal device respectively, so that the signaling overhead is greatly increased, for example, see Figure 5As shown, it is an example diagram of a plurality of terminal devices in an idle state or an inactive state using the above method to obtain multicast configuration information.

[0117] Based on this, the embodiment of the present application provides a communication method and device for reducing the signaling overhead required by the terminal device in the idle state or the inactive state to obtain the multicast configuration information.

[0118] Exemplarily, the communication method provided by the embodiment of the present application can include two possible schemes, which are referred to as scheme one and scheme two for convenience of description. In scheme one, the network device sends first information to the terminal device in the idle state or the inactive state, and correspondingly, the terminal device receives the first information from the network device, and the first information is used to instruct the terminal device to obtain the multicast configuration information through a common channel or a system message; and then the terminal device can receive the common channel or the system message and obtain the multicast configuration information. By using this scheme, on the one hand, the terminal device does not need to enter the connected state, thereby effectively reducing the signaling overhead required by the terminal device and the network device to establish the RRC connection, and also reducing the latency of the terminal device to obtain the multicast configuration; on the other hand, since the network device can send the multicast configuration information through the common channel or the system message, compared with sending the multicast configuration information to the terminal device through the unicast respectively, the processing burden and the signaling overhead of the network device are effectively reduced, and the flexibility of the network device control is also increased. In scheme two, the network device can send the multicast configuration information to the terminal device in the random access process of the terminal device, compared with the way that the network device sends the multicast configuration information to the terminal device after the terminal device enters the connected state, the signaling overhead can be effectively reduced.

[0119] The related technical features involved in the embodiment of the present application are introduced below. It should be noted that these explanations are to make the embodiment of the present application easier to understand, and should not be regarded as limiting the scope of protection required by the present application.

[0120] I. Scrambling

[0121] Scrambling is a processing method of digital signal, which uses scrambling code to perform XOR operation with the original signal to obtain a new signal. The role of uplink physical channel scrambling is usually to distinguish different terminal devices, and downlink scrambling can distinguish cells and channels. Among them, the scrambling code can be used for scrambling and descrambling of the original signal. For example, the scrambling code can be used to scramble the DCI, specifically, the CRC field of the DCI can be scrambled. Correspondingly, the terminal device descrambles the received DCI, specifically, the terminal device descrambles the CRC field of the DCI using the scrambling code of the corresponding type to determine the format or type of the DCI, etc.

[0122] The scrambling codes involved in the embodiments of the present application mainly include: temporary cell radio network temporary identifier (TC-RNTI), random access radio network temporary identifier (RA-RNTI), paging radio network temporary identity (P-RNTI), and G-RNTI.

[0123] II. Random access procedure

[0124] The random access procedure refers to a procedure from sending a random access signal by a terminal device to establishing a basic signaling connection with a network device before accessing the network. The random access signal can be used to initiate the random access procedure, for example, the random access signal can be a random access preamble. The random access procedure can also be referred to as random access or random access method, and the present application does not distinguish between them, and the following description can be used instead.

[0125] According to whether the random access preamble sent by the terminal device is selected by the terminal device itself, the random access procedure can be divided into a contention-based random access procedure and a non-contention-based random access procedure. Among them, the contention-based random access procedure can select the preamble by the terminal device; the non-contention-based random access procedure can allocate the preamble to the terminal device by the network device.

[0126] The following describes some steps included in the random access procedure initiated by the terminal device in the idle state or the inactive state, taking the contention-based random access procedure as an example. Exemplarily, the embodiments of the present application provide two random access procedures, namely a four-step random access procedure and a two-step random access procedure.

[0127] Figure 6a A four-step random access procedure provided by the embodiments of the present application is shown in FIG. 1. As shown in FIG. 1, the following steps are included: Figure 6a

[0128] Step 0: The network device sends random access configuration information to the terminal device, and the terminal device can receive the random access configuration information from the network device. This step can be used for preparation before performing the random access procedure and does not belong to the steps included in the random access procedure. Here, the random access configuration information can be used to configure random access parameters, and the random access parameters can include a random access preamble set.

[0129] ​Step a1: the terminal device sends a random access request to the network device, the random access request can include a random access preamble, and the network device receives the random access preamble from the terminal device. Wherein, the random access request is also referred to as the first message or message 1 (Msg1) in the random access process.

[0130] Here, the random access preamble sent by the terminal device to the network device can be one random access preamble selected from the random access preamble set obtained by the terminal device in step 0 for random access.

[0131] Step a2: after detecting the random access preamble sent by the terminal device, the network device sends a random access response (random access response, RAR) to the terminal device, and the terminal device receives the random access response from the network device, wherein the random access response is also referred to as the second message or message 2 (Msg2) in the random access process.

[0132] Exemplarily, when the network device detects the random access time-frequency resource of the sent preamble, the RA-RNTI (the generation of the RA-RNTI is related to the time-frequency resource used by the terminal device to send the preamble) can be calculated, and the network device uses the RA-RNTI to scramble the DCI. The network device sends response information for the preamble to the terminal device, the terminal device knows the time-frequency resource information of the sent preamble, and can also calculate the RA-RNTI, and then can use the RA-RNTI to listen to the DCI (the DCI is used to schedule the PDSCH carrying the Msg2) on the PDCCH, and then receives the Msg2 according to the listened DCI.

[0133] Exemplarily, the Msg2 can include a timing advance command (timing advance command, TAC), an uplink grant, and a TC-RNTI. Wherein, the uplink grant is used to indicate the uplink resource allocated by the network device for the terminal device, and the TC-RNTI is a temporary identifier allocated by the network device for the terminal device.

[0134] Step a3: the terminal device sends uplink signaling to the network device, and the network device receives the uplink signaling from the terminal device. Wherein, the uplink signaling is also referred to as the third message or message 3 (Msg3) in the random access process.

[0135] Exemplarily, the terminal device can send the Msg3 on the uplink resource indicated by the uplink grant according to the timing advance (timing advance, TA) amount indicated by the TAC. The Msg3 can include common control channel (common control channel, CCCH) information.

[0136] Exemplarily, the Msg3 can be an RRC connection setup request message, an RRC connection reestablishment request message, an RRC connection resume request message, etc.

[0137] Step a4: the network device receives the Msg3 and sends a contention resolution message (CRM) to the terminal device, and correspondingly, the terminal device can receive the contention resolution message from the network device, wherein the contention resolution message is also referred to as a fourth message or message 4 (Msg4).

[0138] Here, when sending the contention resolution message to the terminal device, the network device can scramble the DCI scheduling the contention resolution message by using the TC-RNTI. Correspondingly, after the terminal device listens to the DCI scrambled by the TC-RNTI, the terminal device can receive the contention resolution message according to the DCI, and match the contention resolution identifier (CRID) in the contention resolution message with the common control channel information carried in the Msg3. If the matching is successful, the terminal device considers that the contention resolution is successful, that is, the random access is successful, and then enters the connected state or completes the establishment of the RRC connection; otherwise, the terminal device considers that the random access fails this time.

[0139] Figure 6b A two-step random access process diagram provided by an embodiment of the present application is shown in FIG. 1. As shown in FIG. 1, the two-step random access process includes the following steps: Figure 6b

[0140] Step b1: the terminal device sends a MsgA to the network device.

[0141] Here, the MsgA can also be referred to as message A, and includes a random access preamble and uplink signaling, which is equivalent to the Msg1 and Msg3 in the four-step random access process described above, and can also be understood as "sending the Msg1 and Msg3 together". Figure 6a

[0142] Exemplarily, there can be a corresponding relationship between the random access resource and the PUSCH, and the corresponding relationship can be preconfigured. When the terminal device triggers the random access, the terminal device can select a random access resource to send a random access preamble, and send uplink signaling (such as an RRC connection setup request or an RRC connection reestablishment or an RRC connection resume message) on the PUSCH corresponding to the selected random access resource, and then listen to the MsgB sent by the network device.

[0143] Step b2: the network device sends a MsgB to the terminal device.

[0144] ​​Here, the MsgB, i.e., the response information for the random access request, can also be referred to as message B, and includes at least one of the response information for the random access preamble and the response information for the uplink signaling. The response information for the random access preamble, i.e., the random access response information, can include a TA command, a TC-RNTI, and an UL grant; and the response information for the uplink signaling, i.e., the contention resolution message.

[0145] It should be noted that in the current two-step random access process, when the network device sends the contention resolution identifier to the terminal device in the idle state or the inactive state, the network device can use a common RNTI to scramble the DCI (the DCI is used to schedule the contention resolution message), and accordingly, the terminal device listens to the DCI according to the common RNTI, and receives the contention resolution message according to the received DCI, and further judges whether the random access is successful.

[0146] III. Paging message

[0147] In a wireless communication system, the network device can send messages to the terminal according to different needs of the service, for example, the network device can send a short message (short message) to the terminal device, such as a system message update indication, an earthquake or tsunami notification, etc. The terminal device in the idle state, inactive state or connected state can receive the short message. For another example, the network device can send a paging message (used to page the terminal device) to the terminal device. For this type of paging message, the terminal device in the idle state or the inactive state can receive it, and the terminal device in the connected state does not need to receive it.

[0148] The paging message is introduced as follows. The network device can periodically send the paging message, for example, the network device can send the paging message in a paging occasion (PO) of a paging frame (PF). Figure 6cAs shown, in one paging cycle, there can be multiple paging frames (PFs), and each PF can have multiple POs. Taking terminal device 1 as an example, the network device and the terminal device 1 can both determine the PO corresponding to the terminal device 1 according to the identifier of the terminal device 1, and then the network device can send a DCI (the DCI is used to schedule a paging message, and the DCI is scrambled using a P-RNTI) on the PO corresponding to the terminal device 1, and send the paging message on the time-frequency resource indicated by the DCI; correspondingly, the terminal device 1 can use the P-RNTI to monitor the DCI on the PO, and receive the paging message according to the received DCI to obtain the specific content of the paging message. For example, the paging message can include a paging record list (PagingRecordlist), and the paging record list includes the identifier of one or more terminal devices. After receiving the paging message, the terminal device in the idle state or the inactive state can initiate a random access process to the network device if it is determined that the identifier of the terminal device is included in the paging record list; if it is determined that the identifier of the terminal device is not included in the paging record list, the terminal device can continue to receive the paging message in the next paging cycle.

[0149] Further, the 5G communication system supports multi-beam operation, and beam sweeping paging can be performed to achieve full coverage of paging. In the context of beam sweeping, the time length of one PO is the time length of one beam sweeping cycle, and one PO can include a group of PDCCH monitoring occasions. That is, referring to FIG. 2, one PO can include multiple slots (each slot includes one PDCCH monitoring occasion), and the number of slots included in one PO is determined by the number of system synchronization blocks (SSBs) broadcast by the system. The kth PDCCH monitoring occasion in one PO corresponds to the kth SSB beam. Figure 6d As shown, one PO can include multiple slots (each slot includes one PDCCH monitoring occasion), and the number of slots included in one PO is determined by the number of system synchronization blocks (SSBs) broadcast by the system. The kth PDCCH monitoring occasion in one PO corresponds to the kth SSB beam.

[0150] In the embodiments of the present application, after receiving the paging indication information sent by the core network device, if it is determined that the terminal device needs to be paged, the network device can send a DCI for scheduling a paging message, and then send the paging message on the resource indicated by the DCI.

[0151] Further, after receiving the paging indication information sent by the core network device, the network device can also determine whether a short message needs to be generated according to the needs (such as whether a system message change occurs, whether an earthquake or tsunami needs to be notified, etc.). If a system message change occurs or an earthquake or tsunami needs to be notified, a short message is generated, and the short message includes a system message change indication or an earthquake or tsunami notification. As shown in Table 1, an example of the content of the short message is shown.

[0152] Table 1: Example of short message content

[0153]

[0154] According to Table 1, 8 bits are included in the short message, 1 bit (i.e., bit 1) is used to carry the system message change indication, 1 bit (i.e., bit 2) is used for ETWS message and CMAS message, and the remaining 6 bits (i.e., bits 3-8) are reserved bits.

[0155] After the network device generates the short message, the short message can be carried in the DCI used to schedule the paging message. The DCI used to schedule the paging message can also include a short message indicator. The short message indicator can include 2 bits. In one example, when the value of the 2 bits is "00", it indicates that the 2 bits are reserved bits; when the value of the 2 bits is "01", it indicates that the DCI includes scheduling information of the paging message; when the value of the 2 bits is "10", it indicates that the DCI includes the short message; and when the value of the 2 bits is "11", it indicates that the DCI includes scheduling information of the paging message and the short message.

[0156] Four, common channel

[0157] The common channel can be a channel shared by multiple terminal devices, i.e., multiple terminal devices can receive information on the channel. For example, the common channel can be a multicast control channel (multicast control channel, MCCH) or a single-cell MBMS point-to-multipoint control channel (single cell MBMS point-to-multipoint control channel, SC-MCCH), which is not limited.

[0158] Taking the SC-MCCH as an example, the SC-MCCH is introduced below.

[0159] Two logical channels are introduced in the SC-PTM technology, including SC-MCCH and single-cell multicast transport channel (single cell multicast transport channel, SC-MTCH). The SC-MCCH is only one, which is used to transmit control information, including the configuration information of the SC-MTCH. The SC-MTCH is used to transmit multicast service data. Each multicast service corresponds to an SC-MTCH, as shown in Figure 6e

[0160] ​The SC-MCCH is transmitted in a periodic manner. For example, the network device can broadcast the configuration information of the SC-MCCH through a system message (such as a system information block (SIB) 20), which includes a modification period of the SC-MCCH, a repetition period of the SC-MCCH, and the like, as shown in Figure 6f The network device periodically transmits the SC-MCCH according to the repetition period of the SC-MCCH configured by the SIB 20. The SC-MCCH uses a modification period mechanism, that is, the contents carried by the SC-MCCH transmitted by the network device in the repetition period of a modification period are the same. If the contents carried by the SC-MCCH need to be modified, the network device can start transmitting the SC-MCCH carrying the modified contents, that is, the updated SC-MCCH, from the boundary of the modification period. In addition, the network device can also transmit a modification notification of the SC-MCCH from the boundary of the modification period, which is carried in the DCI scrambled based on a single cell notification radio network temporary identifier (SC-N-RNTI). When the terminal device receives the modification notification of the SC-MCCH, it can receive the SC-MCCH carrying the modified contents, that is, the modification notification of the SC-MCCH and the SC-MCCH carrying the modified contents can be transmitted in the same modification period, as shown in Figure 6f .

[0161] Based on the above description of the related features, the technical solutions provided in the embodiments of the present application will be described in detail in combination with Embodiments 1 to 4.

[0162] Embodiment 1

[0163] In Embodiment 1, a possible implementation of the communication method based on the above-described Scheme 1 will be described.

[0164] Figure 7a The flowchart corresponding to the communication method provided in Embodiment 1 of the present application is shown in Figure 7a , which includes the following steps.

[0165] In step 701, the network device sends first information to the terminal device, and the first information is used to instruct the terminal device to acquire the multicast configuration information of the multicast service through a common channel or a system message.

[0166] Exemplarily, the first information can also be used to indicate that the common channel or the system message changes, where the change of the common channel can be understood as that the information carried by the common channel changes, such as the information carried by the common channel before the change does not include the multicast configuration information of the multicast service, and the information carried by the common channel after the change includes the multicast configuration information of the multicast service; similarly, the change of the system message can be understood as that the information carried by the system message changes, such as the information carried by the system message before the change does not include the multicast configuration information of the multicast service, and the information carried by the system message after the change includes the multicast configuration information of the multicast service. For the common channel, taking the SC-MCCH as an example, it can be known from the foregoing introduction that the network device can send the modification notification of the SC-MCCH to indicate that the SC-MCCH of the terminal device changes; in the embodiment of the application, the network device can also send the first information to the terminal device to indicate that the SC-MCCH of the terminal device changes, and further, the first information can also indicate that the changed SC-MCCH carries the multicast configuration information of the multicast service. For the system message, the network device can send the system message change indication to indicate that the system message of the terminal device changes; in the embodiment of the application, the network device can also send the first information to the terminal device to indicate that the system message of the terminal device changes, and further, the first information can also indicate that the changed system message carries the multicast configuration information of the multicast service.

[0167] Hereinafter, the case that the first information indicates that the terminal device acquires the multicast configuration information of the multicast service through the system message will be described as an example, and the implementation that the first information indicates that the terminal device acquires the multicast configuration information of the multicast service through the common channel can be referred to the related description of the case that the first information indicates that the terminal device acquires the multicast configuration information of the multicast service through the system message, such as, in the introduction below, the content related to the system message can be adaptively replaced by the content related to the common channel.

[0168] Correspondingly, in step 702, the terminal device receives the first information from the network device.

[0169] Here, taking the multicast service as multicast service 1, when multiple terminal devices (such as terminal device 1, terminal device 2, terminal device 3, terminal device 4 and terminal device 5) are interested in the multicast service 1, they can all perform Figure 4bThe core network device and the network device can maintain the correspondence between the identifier of the terminal device and the identifier of the multicast service in which the terminal device is interested according to steps 401 to 404 described above. When the core network device receives the data of the multicast service 1, the core network device can send paging indication information (for example, the identifiers of the terminal device 1 to the terminal device 5) to one or more network devices, so that the terminal device 1 to the terminal device 5 enter the connected state to receive the data of the multicast service 1. Taking the terminal device 1 and the terminal device 2 located in the coverage of the network device 1, and the terminal device 3, the terminal device 4 and the terminal device 5 located in the coverage of the network device 2 as an example, after the network device 1 receives the paging indication information, the network device 1 can page the terminal device 2 first, and then the terminal device 2 enters the connected state. Further, the core network device learns that the terminal device 2 interested in the multicast service 1 is connected to the network device 1, and then the core network device can transmit the data of the multicast service 1 to the network device 1, so that the network device 1 sends the data of the multicast service 1 to the corresponding terminal device in the subsequent process. After the network device 2 receives the paging indication information, the network device 2 can page the terminal device 3 first, and then the terminal device 3 enters the connected state. Further, the core network device learns that the terminal device 3 interested in the multicast service 1 is connected to the network device 2, and then the core network device can transmit the data of the multicast service 1 to the network device 2, so that the network device 2 sends the data of the multicast service 1 to the corresponding terminal device in the subsequent process.

[0170] Taking the network device 1 as an example, after the network device 1 receives the data of the multicast service 1 transmitted by the core network device, if it is determined to transmit the data of the multicast service 1 in a multicast manner, the network device 1 can obtain the multicast configuration information 1 of the multicast service 1. The network device 1 can determine whether to transmit the data of the multicast service 1 in a multicast manner according to various criteria, which are not limited in the embodiments of the present application. The network device can obtain the multicast configuration information 1 of the multicast service 1 in various ways, for example, refer to the prior art.

[0171] Exemplarily, the multicast configuration information of the multicast service can include an identifier of the multicast service and a G-RNTI associated with the multicast service. The identifier of the multicast service can be information used to identify the multicast service. For example, the identifier of the multicast service can include an internet protocol (IP) and / or a port number of the multicast service. The identifier of the multicast service can be sent by the application server to the core network device, and then sent by the core network device to the network device. The multicast configuration information of the multicast service can further include at least one of the following: bandwidth part (BWP) information corresponding to the G-RNTI associated with the multicast service, a PDSCH scrambling sequence of the multicast service, a DRX parameter of the G-RNTI associated with the multicast service, a demodulation reference signal, and a rate matching reference signal. The BWP information corresponding to the G-RNTI includes at least one of the following: bandwidth, frequency location, subcarrier spacing (SCS), cyclic prefix (CP) length, control-resource set (COREST) related configuration information, and PDSCH related configuration information. The COREST information is used to indicate a time-frequency resource of a PDCCH scrambled by the G-RNTI. The PDSCH scrambling sequence of the multicast service is used for the terminal device to descramble the PDSCH of the multicast service using the PDSCH scrambling sequence. The DRX parameter of the G-RNTI is used for the terminal device to perform G-RNTI detection using the DRX parameter. The demodulation reference signal is used for the terminal device to perform PDSCH demodulation of the G-RNTI scheduling using the demodulation reference signal. The rate matching reference signal is used for the terminal device to exclude a position corresponding to the demodulation reference signal when receiving the PDSCH scheduled by the G-RNTI. The identifier of the terminal device mentioned above can be information used to identify the terminal device, such as an international mobile subscriber identification number (IMSI) or a SAE-temporary mobile subscriber identity (S-TMSI).

[0172] Further, after the network device 1 receives the data of the multicast service 1 transmitted by the core network device, the network device 1 can send first information to the terminal device 1, instructing the terminal device 1 to obtain the multicast configuration information 1 through a system message, so as to reduce the signaling overhead caused by the terminal device 1 entering a connected state to obtain the multicast configuration information 1.

[0173] In one example, before sending the first information to the terminal device 1, the network device 1 can further determine whether the number of RRC connections of the network device 1 is greater than a first threshold value. The number of RRC connections of the network device 1 can be understood as the number of all terminal devices that establish RRC connections with the network device 1. For example, if the network device 1 determines that the number of RRC connections is greater than the first threshold value, it means that the number of terminal devices that establish RRC connections with the network device 1 is large, and the processing burden of the network device 1 is large. Therefore, the network device 1 can send the first information to the terminal device 1 to reduce the processing burden of the network device 1. If the number of RRC connections of the network device 1 is less than or equal to the first threshold value, the network device 1 can page the terminal device 1 to enter the connected state to obtain the multicast configuration information, or can also send the first information to the terminal device 1. Which operation is performed depends on the internal implementation of the network device 1.

[0174] In another example, before sending the first information to the terminal device 1, the network device 1 can further determine whether the number of terminal devices that establish RRC connections with the network device 1 and request the same multicast service as the terminal device 1 is greater than a second threshold value (or whether the number of terminal devices that establish RRC connections with the network device 1 and are interested in the multicast service 1 is greater than the second threshold value). If it is greater than the second threshold value, the network device 1 can send the first information to the terminal device 1. If it is less than or equal to the second threshold value, the network device 1 can page the terminal device 1 to enter the connected state to obtain the multicast configuration information 1, or can also send the first information to the terminal device 1.

[0175] The first threshold value or the second threshold value can be agreed by a protocol, or can be pre-configured for the network device 1. For example, the first threshold value or the second threshold value can be related to the processing capability of the network device 1.

[0176] For example, if the terminal device 2 enters the connected state to obtain the multicast configuration information 1 of the multicast service 1, and the terminal device 1 obtains the multicast configuration information 1 of the multicast service 1 through the system message, the multicast configuration information 1 obtained by the terminal device 1 and the multicast configuration information 1 obtained by the terminal device 2 can be the same.

[0177] In the embodiments of the present application, there can be multiple implementation manners for the network device to send the first information to the terminal device. Three possible manners are exemplarily described below.

[0178] Manner 1

[0179] The first information can be carried in the paging message sent by the network device to the terminal device. Further, the paging message can also include a paging record list. When the terminal device receives the paging message sent by the network device, if it is determined that the paging message includes the identifier of the terminal device, the terminal device can initiate a random access process to enter a connected state to obtain the multicast configuration information. If it is determined that the paging message does not include the identifier of the terminal device, the terminal device can determine, according to the first information, that the multicast configuration information needs to be obtained through a system message.

[0180] Exemplarily, the first information can be indicated in various ways. In one example, the first information can include one bit. For example, if the value of the one bit is 1, it indicates that the terminal device obtains the multicast configuration information of the multicast service through a system message. If the value of the one bit is 0, it indicates that the terminal device does not obtain the multicast configuration information of the multicast service through a system message. For another example, if the first information is included in the paging message, it indicates that the terminal device obtains the multicast configuration information of the multicast service through a system message. If the first information is not included in the paging message, it indicates that the terminal device does not obtain the multicast configuration information of the multicast service through a system message.

[0181] In yet another example, the first information can include the identifier of the multicast service. For example, when the identifier of the multicast service is included in the paging message, it indicates that the terminal device obtains the multicast configuration information of the multicast service corresponding to the identifier of the multicast service through a system message. When the identifier of the terminal device is not included in the paging message, it indicates that the terminal device does not obtain the multicast configuration information of the multicast service corresponding to the identifier of the multicast service through a system message. Exemplarily, the existing paging message can be extended. For example, a first field is added to the paging message, and the first field is used to carry the first information. The first field can be PagingforService-IEs. The following is an example of the format of the extended paging message:

[0182]

[0183] Method 2

[0184] The network device sends a first DCI to the terminal device, and the first DCI is used to schedule a paging message. The first DCI can transmit the first information in an explicit or implicit manner, and further indicate the terminal device to obtain the multicast configuration information through a system message.

[0185] In one example, the first information is included in the first DCI, for example, the first information can include 1 bit, for another example, the first information can include an identifier of the multicast service; and then after the terminal device receives the first DCI, the terminal device can determine that the multicast configuration information needs to be acquired through the system message according to the first information. If the first DCI includes a short message, the first information can be carried in the reserved bit in the short message, so as to save the resource overhead of the first DCI.

[0186] Further, the reserved bit can have a corresponding relationship with the identifier of the multicast service, and the corresponding relationship can be one-to-one (for example, one bit corresponds to the identifier of one multicast service), one-to-many (for example, one bit corresponds to the identifiers of multiple multicast services), or many-to-many (for example, multiple bits correspond to the identifiers of multiple multicast services). For example, if the corresponding relationship is one-to-one, that is, bits 3-8 correspond to the identifiers of multicast service 1 to multicast service 6 respectively, after the terminal device receives the first DCI, if the value of bit 3 is 1, the terminal device determines that the multicast configuration information of multicast service 1 needs to be acquired through the system message. The corresponding relationship between the reserved bit and the identifier of the multicast service can be predefined by a protocol, or can be configured for the terminal device by the network device, for example, the network device can configure the terminal device through a broadcast message.

[0187] Optionally, the format of the first DCI can be DCI format 1A or DCI format 6-2 or other possible formats, which are not limited here.

[0188] In this example, since the network device adds the first information in the first DCI (or the first information is carried in the first DCI), it can be understood that the first DCI indicates the terminal device to acquire the multicast configuration information through the system message in an explicit manner.

[0189] In another example, the first DCI can be scrambled by a first RNTI, and the first RNTI is different from the P-RNTI, and then after the terminal device receives the first DCI scrambled by the first RNTI, the terminal device can determine that the multicast configuration information needs to be acquired through the system message. The first RNTI can be a newly defined RNTI, and the first RNTI can be predefined by a protocol or configured for the terminal device by the network device before the paging process, for example, the network device can configure the terminal device through a broadcast message (the broadcast message can be RRC signaling). In this example, the network device can not change the content of the first DCI, but scramble the first DCI through the first RNTI, so as to indicate the terminal device to acquire the multicast configuration information through the system message in an implicit manner, and in this case, the first DCI can also be understood as the first information.

[0190] In yet another example, the network device can send the first DCI on the first preset time-frequency resource, and then the terminal device can determine that the multicast configuration information needs to be acquired through the system message after receiving the first DCI on the first preset time-frequency resource. The first preset time-frequency resource can be predefined by the protocol or configured by the network device for the terminal device before the paging process, for example, the network device can configure the first preset time-frequency resource for the terminal device through a broadcast message. The first preset time-frequency resource can be time-frequency resources corresponding to part of PDCCH monitoring moments included in the PO corresponding to the terminal device, for example, the PO corresponding to the terminal device includes 10 PDCCH monitoring moments, which are PDCCH monitoring moment 1 to PDCCH monitoring moment 10, and the first preset time-frequency resource can be time-frequency resources corresponding to PDCCH monitoring moment 2 and PDCCH monitoring moment 5. That is, if the terminal device receives the first DCI at PDCCH monitoring moment 2 or PDCCH monitoring moment 5, it can be determined that the multicast configuration information needs to be acquired through the system message.

[0191] In this way, after the terminal device receives the first DCI, the terminal device can acquire the multicast configuration information through the system message without receiving the paging message, so that the network device can not send the paging message for paging the terminal device after sending the first DCI, thereby saving the paging signaling overhead.

[0192] Method 3

[0193] The network device can send a downlink message to the terminal device in the random access process of the terminal device, and the downlink message can carry the first information in an explicit or implicit manner, that is, the terminal device is instructed to acquire the multicast configuration information through the system message in an explicit or implicit manner. The downlink message can be Msg4 in the four-step random access process or the second DCI for scheduling Msg4, or the downlink message can also be MsgB in the two-step random access process or the third DCI for scheduling MsgB.

[0194] For example, the network device can establish and store a mapping relationship between the identity of the terminal device (and / or the identity of the multicast service interested by the terminal device) and the access reason. The access reason can include multiple types, and for ease of description, the access reason is divided into two types in the embodiments of the present application. The first access reason is to acquire multicast configuration information, and the access reason other than the first access reason is collectively referred to as the second access reason. The network device can establish the mapping relationship between the identity of the terminal device and the access reason in multiple ways, for example, after the network device determines to transmit the data of the multicast service 1 in a multicast manner, the network device can determine that the access reason of the terminal device interested in the multicast service 1 is to acquire the multicast configuration information 1 of the multicast service 1. As shown in Table 2, an example of the network device storing the mapping relationship between the identity of the terminal device and the access reason.

[0195] Table 2: An example of mapping relationship between the identity of the terminal device and the access reason

[0196] Identity of the terminal device Access cause Identity of the terminal device 1 First access cause Identity of the terminal device 2 First access cause Identity of the terminal device 3 First access cause Identity of the terminal device 4 Second access cause

[0197] Exemplarily, since the random access procedure of the terminal device can be a four-step random access procedure or a two-step random access procedure, the following will be introduced respectively for the two cases.

[0198] Case 1: the random access procedure is a four-step random access procedure

[0199] For case 1, the identity of the terminal device and / or the identity of the multicast service interested by the terminal device can be included in the Msg3 sent by the terminal device to the network device, and accordingly, the network device determines the access reason of the terminal device according to the identity of the terminal device and / or the identity of the multicast service interested by the terminal device and the pre-stored mapping relationship. Alternatively, the access reason value can be included in the Msg3 sent by the terminal device to the network device, and accordingly, the network device can determine the access reason of the terminal device according to the access reason value.

[0200] The terminal device can determine the access reason in multiple ways. For example, after the core network device determines that the data of the multicast service arrives, the core network device can send the identity of the multicast service to the network device, such as carrying the identity of the multicast service in the paging indication information sent by the core network device to the network device; then the network device can carry the identity of the multicast service in the paging message to indicate that the data of the multicast service of the terminal device arrives, according to the paging indication information when paging the terminal device; accordingly, if the terminal device determines that the identity of the multicast service carried in the paging message is the identity of the multicast service interested by itself, the terminal device can generate an access reason value (the access reason value is used to indicate obtaining multicast configuration information) and carry it in the above-mentioned Msg3 to send to the network device.

[0201] In one example, the terminal device includes the identity of the terminal device and / or the identity of the multicast service interested by the terminal device in the Msg3 sent to the network device, and accordingly, the network device determines the access cause of the terminal device according to the identity of the terminal device and / or the identity of the multicast service interested by the terminal device and the pre-stored mapping relationship, and if it is determined that the access cause of the terminal device is the first access cause, the network device can carry the first information in the Msg4 sent to the terminal device, and the first information can include 1 bit or the identity of the multicast service, and then the terminal device can determine that the multicast configuration information needs to be acquired through the system message according to the Msg4 after receiving the Msg4. In this example, since the content of the Msg4 of the network device, that is, the first information is added in the Msg4 (or the first information is carried in the Msg4), it can be understood that the Msg4 carries the first information in an explicit manner, that is, indicates the terminal device to acquire the multicast configuration information through the system message in an explicit manner.

[0202] In another example, the terminal device can include the identity of the terminal device and / or the identity of the multicast service interested by the terminal device in the Msg3 sent to the network device, and accordingly, the network device determines the access cause of the terminal device according to the identity of the terminal device and / or the identity of the multicast service interested by the terminal device and the pre-stored mapping relationship, and if it is determined that the access cause of the terminal device is the first access cause, the network device can send the second DCI to the terminal device, and the second DCI is used to schedule the Msg4. The second DCI can carry the first information in an explicit or implicit manner, that is, indicates the terminal device to acquire the multicast configuration information through the system message in an explicit or implicit manner, such as the second DCI can include the first information (explicit), or the second DCI can be scrambled by a newly defined second RNTI (implicit), or the second DCI can be carried on the second pre-set time-frequency resource (implicit).

[0203] In this way, since the terminal device can acquire the multicast configuration information through the system message after receiving the second DCI, it is not necessary to receive the Msg4 again, and therefore, the network device can not need to send the Msg4 again after sending the second DCI, thereby saving the signaling overhead.

[0204] Case 2: the random access procedure is a two-step random access procedure

[0205] For case 2, the terminal device can include the identity of the terminal device and / or the identity of the multicast service interested by the terminal device in the MsgA sent to the network device, and accordingly, the network device determines the access cause of the terminal device according to the identity of the terminal device and / or the identity of the multicast service interested by the terminal device and the pre-stored mapping relationship. Alternatively, the terminal device can include the access cause value in the MsgA sent to the network device, and accordingly, the network device can determine the access cause of the terminal device according to the access cause value.

[0206] In one example, the MsgA sent by the terminal device to the network device can include an identifier of the terminal device and / or an identifier of the multicast service interested by the terminal device, and accordingly, the network device can carry the first information in the MsgB sent to the terminal device according to the identifier of the terminal device and / or the identifier of the multicast service interested by the terminal device and the pre-stored mapping relationship, and if it is determined that the access cause of the terminal device is the first access cause, the first information can include 1 bit or the identifier of the multicast service, and then the terminal device can determine that the multicast configuration information needs to be acquired through the system message according to the MsgB after receiving the MsgB. In this example, since the content of the MsgB of the network device, that is, the first information is added in the MsgB (or the first information is carried in the MsgB), it can be understood that the MsgB carries the first information in an explicit manner, that is, indicates the terminal device to acquire the multicast configuration information through the system message in an explicit manner.

[0207] In another example, the MsgA sent by the terminal device to the network device can include an identifier of the terminal device and / or an identifier of the multicast service interested by the terminal device, and accordingly, the network device can send the third DCI to the terminal device according to the identifier of the terminal device and / or the identifier of the multicast service interested by the terminal device and the pre-stored mapping relationship, and if it is determined that the access cause of the terminal device is the first access cause, the third DCI is used to schedule the MsgB. The third DCI can carry the first information in an explicit or implicit manner, that is, indicates the terminal device to acquire the multicast configuration information through the system message in an explicit or implicit manner, such as the third DCI can include the first information (explicit), or the third DCI can be scrambled by a newly defined third RNTI (implicit), or the third DCI can be carried on the third preset time-frequency resource (implicit).

[0208] In this example, since the terminal device can acquire the multicast configuration information through the system message after receiving the third DCI, it is not necessary to receive the MsgB again, and therefore, the network device can not need to send the MsgB again after sending the third DCI, thereby saving the signaling overhead.

[0209] In step 703, the network device sends a system message, and the system message includes the multicast configuration information.

[0210] Accordingly, in step 704, the terminal device receives the system message from the network device, and then acquires the multicast configuration information.

[0211] Exemplarily, in step 703, the network device can periodically send system messages, for example, the network device can send system messages according to a repetition period of the system messages. When the network device obtains the multicast configuration information, the network device can carry the multicast configuration information in the system messages. For the convenience of distinguishing, the system messages not carrying the multicast configuration information are referred to as first system messages in the embodiments of the present application, and the system messages carrying the multicast configuration information are referred to as second system messages. Referring to FIG. 7, which is a schematic diagram of the system messages periodically sent by the network device; in the system message change period 0, the network device sends the first system messages, and then the network device obtains the multicast configuration information and carries the multicast configuration information in the system messages, and further sends the second system messages in the system message change period 1 and the system message change period 2. It should be noted that in one system message change period, the contents of the system messages sent by the network device according to the repetition period can be the same. Figure 7b

[0212] In a possible implementation, after receiving the first information, the terminal device can immediately receive the system messages to obtain the multicast configuration information, or can be ready to receive the system messages at the nearest system message sending moment, or can receive the second system messages from the network device in the same system message change period or the same frame or the same subframe or the same time slot or the same sub-slot as the first information. For example, referring to FIG. 8, which shows that the first information and the second system messages in the period 2 are located in the same system message change period, and then the terminal device can receive the second system messages in the same system message change period (i.e., the system message change period 2) after receiving the first information. In this way, the terminal device can obtain the multicast configuration information in time, and reduce the time delay of the terminal device obtaining the multicast configuration. Figure 7b

[0213] In another possible implementation, after receiving the first information, the terminal device can receive the system messages to obtain the multicast configuration information at a first moment. The terminal device can determine the first moment in multiple ways. In one example, the first moment can be predefined by a protocol, for example, the first moment can be the end moment of the time domain resource carrying the first information, which is the nearest frame boundary or subframe boundary or time slot boundary. In another example, the network device can send indication information to the terminal device, the indication information can be used to indicate the first moment, and then the network device can determine the first moment according to the indication information; wherein the indication information can be included in the first information, or the indication information and the first information can be sent through the same message, which is not limited. In this way, the network device indicates the first moment, which can effectively ensure that the terminal device obtains the multicast configuration information through the system messages, and avoid the terminal device needing to continuously detect the system messages for a long time.

[0214] ​​In this example, the indication information can indicate the first time in multiple ways. For example, in one possible indication manner, the indication information can include time information of the first time. For example, the first time is a time point in absolute time (such as coordinated universal time (UTC) or global positioning system (GPS) time). For example, if the first time is X1 hours, X2 minutes, X3 seconds, X4 milliseconds and X5 microseconds, the indication information can include the values of X1, X2, X3, X4 and X5. In another possible indication manner, the indication information can be used to indicate a first time length. The first time length can be understood as a time offset. For example, the end time of the time domain resource carrying the first information is taken as a reference, and the end time of the time domain resource carrying the first information plus the first time length can obtain the first time. That is, the first time length can be the time length between the end time of the time domain resource carrying the first information and the first time, or the first time length can be the time offset of the first time relative to the end time of the time domain resource carrying the first information. The unit of the first time length can be a time unit in absolute time, such as second, millisecond, microsecond or nanosecond, or can be a time slot, a micro time slot, a subframe, or can be another possible time unit, which is not limited.

[0215] By using the above method, the terminal device can obtain the multicast configuration information through the system message according to the indication of the network device, so that the terminal device does not need to enter the connected state to obtain the multicast configuration information. On the one hand, the signaling overhead can be effectively saved, and the time delay of the terminal device to obtain the multicast configuration is also reduced. On the other hand, the network device can instruct the terminal device to obtain the multicast configuration information through the system message, so that the flexibility of the network device control is improved.

[0216] Embodiment Two

[0217] In embodiment two, a possible flow of the scheme related to embodiment one will be described.

[0218] Figure 8a A flowchart of a communication method according to embodiment two is shown in FIG. 8. As shown in FIG. 8, the method includes the following steps. Figure 8a

[0219] It is assumed that the terminal device 1, the terminal device 2 and the terminal device 3 are terminal devices interested in the multicast service 1, and the terminal device 1, the terminal device 2 and the terminal device 3 are all within the coverage of the network device 1. The terminal device 1 and the terminal device 2 are in an idle state or an inactive state, and the terminal device 3 is in a connected state.

[0220] In step 801, the core network device receives data of the multicast service 1.​

[0221] In step 802, the core network device sends paging indication information to the network device 1, and the paging indication information includes the identities of the terminal device 1 and the terminal device 2.

[0222] Here, according to the corresponding relationship maintained by the core network device, it is known that the terminal devices interested in the multicast service 1 include the terminal device 1, the terminal device 2, and the terminal device 3. Since the terminal device 3 is in the connected state, the paging indication information can include the identities of the terminal device 1 and the terminal device 2.

[0223] Further, the core network device knows that the terminal device 3 is in the connected state and is located in the coverage range of the network device 1, and thus can send the data of the multicast service 1 to the network device 1. Correspondingly, the network device 1 can receive the data of the multicast service 1.

[0224] If the network device 1 determines to send the data of the multicast service 1 in a multicast manner, it can generate multicast configuration information and send the multicast configuration information to the terminal device 3, and thus the terminal device 3 can receive the data of the multicast service 1 according to the multicast configuration information.

[0225] In step 803, the network device 1 receives the paging indication information and determines that the terminal device 1 and the terminal device 2 need to be paged.

[0226] In step 804, the network device 1 sends a paging message 2 to the terminal device 2, and the paging record list in the paging message 2 includes the identity of the terminal device 2.

[0227] In step 805, after receiving the paging message 2 from the network device 1, the terminal device 2 establishes an RRC connection with the network device 1, and thus the terminal device 2 enters the connected state.

[0228] In step 806, the network device 1 sends multicast configuration information of the multicast service 1 to the terminal device 2, and thus the terminal device 2 can receive the data of the multicast service 1 according to the multicast configuration information.

[0229] Here, the network device 1 can send the multicast configuration information to the terminal device 2 in a plurality of possible ways, such as through DCI, medium access control control element (MAC CE), or RRC signaling, which is not limited in detail.

[0230] In step 807, the network device 1 sends a paging message 1 to the terminal device 1, and the paging message 1 includes first information (such as the identity of the multicast service 1), and the paging record list in the paging message 1 does not include the identity of the terminal device 1.

[0231] Here, the network device 1 can send the paging message 1 to the terminal device 1 after determining that the number of RRC connections of the network device 1 is greater than or equal to the first threshold.

[0232] At step 808, the terminal device 1 receives the paging message 1 and determines, according to the paging message 1, that the multicast configuration information of the multicast service 1 needs to be acquired through the system message.

[0233] At step 809, the network device 1 sends the system message, and the system message includes the multicast configuration information of the multicast service 1.

[0234] At step 810, the terminal device 1 receives the system message and acquires the multicast configuration information of the multicast service 1. Then, the terminal device 1 can receive the data of the multicast service 1 according to the multicast configuration information.

[0235] According to the above content, when there are a large number of terminal devices in an idle state or an inactive state in the network, by using the above method, the network device can instruct a part of the terminal devices to acquire the multicast configuration information through the system message, thereby realizing that a part of the terminal devices acquire the multicast configuration information through the system message, and another part of the terminal devices enter the connected state to acquire the multicast configuration information, as shown in Figure 8b , compared with all terminal devices in the idle state or the inactive state entering the connected state to acquire the multicast configuration information (as shown in Figure 5 ), the signaling overhead is greatly reduced.

[0236] Embodiment Three

[0237] According to the description in the above embodiment two, the terminal device 1 is in an idle state or an inactive state to receive the data of the multicast service 1, and the terminal device 2 and the terminal device 3 are in a connected state to receive the data of the multicast service 1. Figure 8a The flowchart shown in

[0238] Therefore, in the embodiments of the present application, a solution can be provided, for example, the network device 1 can instruct the terminal devices in the connected state to receive the data of the multicast service 1 in the idle state or the inactive state, thereby reducing the processing burden of the network device 1. This solution can be applied to the scenario described in embodiment two, or can also be applied to other possible scenarios, for example, it can also be applied to the scenario described in Figure 4b , without limitation.

[0239] For example, the network device 1 can send a first message to the terminal device 2, the first message is used to instruct the terminal device 2 to receive the data of the multicast service 1 in the idle state or the inactive state, or in other words, the first message is used to instruct the terminal device 2 to release from the connected state to the idle state or the inactive state without releasing the multicast configuration information of the multicast service 1. For example, the first message can be an RRC connection release message or an RRC connection suspend message, and the RRC connection release message or the RRC connection suspend message can include a field 1, the field 1 is used to carry indication information, the indication information is used to indicate that the multicast configuration information of the multicast service 1 is not released. The field 1 can include one bit, when the value of the bit is 1, it indicates that the multicast configuration information of the multicast service 1 is not released, or when the field 1 is included in the RRC connection release message or the RRC connection suspend message, it indicates that the multicast configuration information of the multicast service 1 is not released. The first message can also be other possible RRC messages, which are not limited in detail. Correspondingly, after the terminal device 2 receives the first message, the terminal device 2 can release from the connected state to the idle state or the inactive state without releasing the multicast configuration information of the multicast service 1, that is, receive the data of the multicast service 1 in the idle state or the inactive state.

[0240] In the embodiment of the application, since the terminal device 2 does not release the multicast configuration information of the multicast service 1, the terminal device 2 can receive the data of the multicast service 1 in the idle state or the inactive state. The terminal device 2 does not release the multicast configuration information of the multicast service 1 can also have other possible description methods, for example, the terminal device 2 does not release the data radio bearer (DRB) configured by the network device 1 for the terminal device to carry the data of the multicast service 1.

[0241] For example, the network device 1 instructs the terminal device in the connected state to receive the data of the multicast service 1 in the idle state or the inactive state, which can depend on the internal implementation of the network device 1.

[0242] In a possible implementation (referred to as implementation 1), the network device 1 can instruct a terminal device (or a terminal device in near coverage) that is closer to the network device 1 to receive data of the multicast service 1 in an idle state or an inactive state, and a terminal device (or a terminal device in far coverage) that is farther away from the network device 1 can receive data of the multicast service in a connected state. Since the terminal device in near coverage has better reception quality, instructing the terminal device in near coverage to receive data of the multicast service 1 in an idle state or an inactive state can effectively reduce the processing burden of the network device on the premise of ensuring reception of the multicast service. The network device 1 can determine whether a terminal device is closer to the network device 1 according to various manners. For example, the network device 1 can determine whether the terminal device is closer to the network device 1 according to one or more of reference signal receiving power (RSRP), reference signal receiving quality (RSRQ), and received signal strength indication (RSSI) of the terminal device, and channel quality information (CQI). For another example, the network device 1 can determine whether the terminal device is closer to the network device 1 according to a measurement result of a sounding reference signal (SRS) of the terminal device. For example, if the network device 1 determines that the RSRP of the terminal device 2 is greater than a third threshold, it indicates that the terminal device 2 is closer to the network device 1, and then the network device 1 can send a first message to the terminal device 2, instructing the terminal device 2 to release from the connected state to the idle state or the inactive state without releasing multicast configuration information of the multicast service 1, that is, instructing the terminal device 2 to receive data of the multicast service 1 in the idle state or the inactive state. The third threshold can be pre-agreed by a protocol or determined by the network device itself, and is not limited specifically.

[0243] In this implementation, considering that the terminal device has mobility, such as the terminal device 2 can move from a position close to the network device 1 to a position far from the network device 1; when the terminal device 2 moves to a position far from the network device 1, if it still receives the data of the multicast service 1 in the idle state or the inactive state, an exception can occur. To solve this problem, an embodiment of the present application can provide a solution, such as when the terminal device determines that it is not suitable to receive the data of the multicast service 1 in the idle state or the inactive state, it can initiate random access to enter the connected state to receive the data of the multicast service 1. This solution can be applicable to the terminal device 2 described above, or can also be applicable to other terminal devices that are not suitable to receive the data of the multicast service 1 in the idle state or the inactive state, without limitation.

[0244] Wherein, the terminal device determines whether it is suitable to receive the data of the multicast service 1 in the idle state or the inactive state in multiple ways, such as the terminal device can determine whether it is suitable to receive the data of the multicast service 1 in the idle state or the inactive state based on at least one of RSRP, RSRQ, RSSI. For example, following the above example, when the terminal device 2 receives the data of the multicast service 1 in the idle state or the inactive state, if it determines that the RSRP of the terminal device 2 is less than the fourth threshold value, it can initiate random access to enter the connected state to receive the data of the multicast service 1. Wherein, the fourth threshold value can be determined by the network device and sent to the terminal device.

[0245] In addition, after the data transmission of the multicast service 1 is completed, the network device 1 can also keep at least one terminal device interested in the multicast service 1 in the connected state, so that the core network device can know that the data of the multicast service 1 needs to be sent to the network device 1 based on the terminal device in the connected state after determining that the data of the multicast service 1 arrives. Wherein, the network device 1 can determine which terminal device or which terminal devices continue to be in the connected state according to at least one of RSRP, RSRQ, RSSI, CQI of the terminal device; for example, the network device 1 can determine which terminal device or which terminal devices continue to be in the connected state according to the measurement result of the SRS of the terminal device; for example, the network device 1 determines whether the RSRP of the terminal device is greater than the fifth threshold value, if so, it can determine whether the terminal device continues to be in the connected state. For example, the terminal device can also determine whether to continue to be in the connected state according to at least one of RSRP, RSRQ, RSSI, such as the terminal device determines that the RSRP of the terminal device is greater than the sixth threshold value, it can determine to continue to be in the connected state. Wherein, the fifth threshold value can be pre-defined by the protocol or determined by the network device itself; the sixth threshold value can be determined by the network device and sent to the terminal device. In one example, the fifth threshold value and the sixth threshold value can be the same.

[0246] In another possible implementation (referred to as implementation 2), the network device 1 can instruct a terminal device far away from the network device 1 to receive data of the multicast service 1 in the idle state or the inactive state, and a terminal device close to the network device 1 can receive data of the multicast service in the connected state. By letting the terminal device far away from the network device 1 receive the multicast service in the idle state or the inactive state, the processing burden of the network device can be effectively reduced. For example, to ensure that the terminal device far away from the network device 1 can effectively receive the multicast service in the idle state or the inactive state, the network device in the embodiment of the present application can use a low-order modulation mode or other possible mode to transmit the multicast service.

[0247] For example, if the network device 1 determines that the RSRP of the terminal device 2 is less than or equal to the seventh threshold value, it indicates that the terminal device 2 is far away from the network device 1, and then the network device 1 can send a first message to the terminal device 2, instructing the terminal device 2 to release from the connected state to the idle state or the inactive state without releasing the multicast configuration information of the multicast service 1, that is, instructing the terminal device 2 to receive data of the multicast service 1 in the idle state or the inactive state. The seventh threshold value can be pre-defined by a protocol or determined by the network device itself.

[0248] It should be noted that the difference between implementation 2 and implementation 1 is that in implementation 1, the terminal device close to the network device receives data of the multicast service 1 in the idle state / inactive state, while in implementation 2, the terminal device far away from the network device receives data of the multicast service in the idle state / inactive state. Except for this difference, the two can be mutually referred to. For example, in implementation 2, the specific implementation of "a manner in which the terminal device determines whether it is suitable to receive data of the multicast service 1 in the idle state or the inactive state" and "after the transmission of data of the multicast service 1 is completed, the network device 1 can also keep at least one terminal device interested in the multicast service 1 in the connected state" can be adaptively referred to the related description of implementation 1 described above.

[0249] Embodiment Four

[0250] In embodiment four, a possible implementation of the communication method based on the above scheme two will be described.

[0251] Figure 9a The flowchart corresponding to the communication method provided by the embodiment four of the present application is shown in FIG. 9, and the method comprises the following steps. Figure 9a

[0252] In step 901, the terminal device sends an identifier of the terminal device and / or an identifier of a multicast service interested by the terminal device to the network device in a random access process.

[0253] In step 902, the network device receives the identifier of the terminal device and / or the identifier of the multicast service interested by the terminal device.​

[0254] At step 903, the network device determines the access cause of the terminal device according to the identifier of the terminal device and / or the identifier of the multicast service interested by the terminal device and the stored mapping relationship. If the access cause of the terminal device is to acquire multicast configuration information, step 904 is performed, otherwise, the random access procedure is continued.

[0255] At step 904, the network device sends a downlink message in the random access procedure to the terminal device, and the downlink message includes the multicast configuration information.

[0256] At step 905, the terminal device receives the downlink message and acquires the multicast configuration information.

[0257] Exemplarily, the random access procedure described above can be a four-step random access procedure or a two-step random access procedure. If the random access procedure described above is a four-step random access procedure, the terminal device can carry the identifier of the terminal device and / or the identifier of the multicast service interested by the terminal device in Msg3 at step 901, and then the downlink message sent by the network device at step 904 can be Msg4 or can also be DCI for scheduling Msg4. If the random access procedure described above is a two-step random access procedure, the terminal device can carry the identifier of the terminal device and / or the identifier of the multicast service interested by the terminal device in MsgA at step 901, and then the downlink message sent by the network device at step 904 can be MsgB or can also be DCI for scheduling MsgB.

[0258] By using the method described above, the network device can send the multicast configuration information to the terminal device in the random access procedure, thereby effectively saving the signaling overhead of the terminal device for acquiring the multicast configuration information.

[0259] For the above-mentioned embodiments one to four, it should be noted that: (1) the above-mentioned embodiments one and four can be implemented separately in different scenarios, or can be combined and implemented in the same scenario, or different schemes involved in different embodiments can also be combined and implemented (for example, part or all of the schemes involved in embodiment three can be combined and implemented with embodiment two), and the specific implementation is not limited. For example, see Figure 9bAs shown, when there are a large number of terminal devices in the idle state or the inactive state in the network (for the convenience of description, these terminal devices are divided into three groups), the network device can instruct the terminal devices in the first group to enter the connected state to obtain the multicast configuration information, instruct the terminal devices in the second group to obtain the multicast configuration information through the system message (i.e., the method in Embodiment 1 is adopted), and send the multicast configuration information to the terminal devices in the third group through the downlink message in the random access process of the terminal devices (i.e., the method in Embodiment 4 is adopted). In a specific implementation, which terminal devices are allowed by the network device to enter the connected state to obtain the multicast configuration information, which terminal devices are allowed by the network device to obtain the multicast configuration information through the system message, and which terminal devices are allowed by the network device to receive the multicast configuration information through the downlink message in the random access process of the terminal devices depend on the internal implementation of the network device, and are not specifically limited.

[0260] (2) The step numbers of each flowchart (such as Figure 7a , Figure 8a , Figure 9a ) described in the embodiments of the present application are only an example of the execution flow, and do not constitute a limitation on the execution sequence of the steps. The steps in the embodiments of the present application that do not have a time sequence dependency relationship between each other do not have a strict execution sequence.

[0261] The above describes the scheme provided by the embodiments of the present application mainly from the perspective of the interaction between the network device and the terminal device. It can be understood that, in order to implement the above functions, the network device or the terminal device can include a hardware structure and / or a software module corresponding to each function. Those skilled in the art should easily realize that, in combination with the units and algorithm steps of the examples described in the embodiments disclosed in the present text, the embodiments of the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a certain function is implemented in the form of hardware or computer software driven hardware depends on the specific application of the technical scheme and the design constraint conditions. The skilled person can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0262] The embodiments of the present application can divide the functional units of the terminal device and the network device according to the above method examples. For example, each functional unit can be divided according to each function, or two or more functions can be integrated into one unit. The integrated unit can be implemented in the form of hardware or a software functional unit.

[0263] In the case of an integrated unit, Figure 10 A possible exemplary block diagram of the apparatus involved in the embodiments of the present application is shown. As Figure 10As shown, the apparatus 1000 can include a processing unit 1002 and a communication unit 1003. The processing unit 1002 is configured to control and manage actions of the apparatus 1000. The communication unit 1003 is configured to support communication of the apparatus 1000 with other devices. Optionally, the communication unit 1003, also referred to as a transceiver unit, can include a receiving unit and / or a transmitting unit, which are configured to perform receiving and transmitting operations, respectively. The apparatus 1000 can further include a storage unit 1001 configured to store program codes and / or data of the apparatus 1000.

[0264] The apparatus 1000 can be a terminal device in any of the above embodiments, or can also be a chip disposed in a terminal device. The processing unit 1002 can support the apparatus 1000 to perform actions of a terminal device in the above method examples. Alternatively, the processing unit 1002 mainly performs internal actions of a terminal device in the method examples, and the communication unit 1003 can support communication between the apparatus 1000 and a network device. For example, the communication unit 1003 can be configured to perform Figure 7a steps 702 and 704 in the method 700, Figure 8a steps 808 and 810 in the method 800, and Figure 9a steps 901 and 905 in the method 900.

[0265] In one embodiment, the communication unit 1003 is configured to receive first information from a network device, the first information being used to indicate that the terminal device acquires multicast configuration information through a system message, the multicast configuration information being used to indicate that the terminal device receives a multicast service; and receive the system message from the network device, the system message including the multicast configuration information.

[0266] In a possible design, the terminal device is in a radio resource control (RRC) idle state or an RRC inactive state.

[0267] In a possible design, the multicast configuration information includes a group-radio network temporary identifier (G-RNTI) associated with the multicast service and an identifier of the multicast service.

[0268] In a possible design, the first information is carried in a paging message from the network device.

[0269] In a possible design, the paging message includes a paging record list, and the paging record list does not include an identifier of the terminal device.

[0270] In a possible design, the first information includes an identifier of the multicast service.

[0271] In one possible design, the first information is carried in a first downlink control information from the network device, the first downlink control information being used to schedule a paging message.

[0272] In one possible design, the first information is a first downlink control information from the network device, the first downlink control information being used to schedule a paging message; wherein the first downlink control information is scrambled by a first RNTI, the first RNTI being different from a P-RNTI; or the first downlink control information is transmitted via a preconfigured time-frequency resource.

[0273] In one possible design, the first information is carried in a downlink message in a random access procedure performed by the terminal device; wherein the downlink message is a contention resolution message; or the downlink message is a second downlink control information, the second downlink control information being used to schedule the contention resolution message.

[0274] In one possible design, the communication unit 1003 is further configured to send, to the network device, an identity of the terminal device and / or an identity of the multicast service in the random access procedure.

[0275] In one possible design, the communication unit 1003 is specifically configured to receive, from the network device, the system message in a same system message modification period, or a same frame, or a same subframe, or a same time slot, or a same sub-time slot as where the first information is located.

[0276] The apparatus 1000 can be the network device in any of the preceding embodiments, or can also be a chip disposed in the network device. The processing unit 1002 can support the apparatus 1000 to perform the actions of the network device in the method embodiments. Alternatively, the processing unit 1002 mainly performs the internal actions of the network device in the method embodiments, and the communication unit 1003 can support the communication between the apparatus 1000 and the terminal device. For example, the processing unit 1002 can be configured to perform the step 803 in the method embodiment of Figure 8a Figure 9a the step 903 in the method embodiment of Figure 7a the steps 701 and 703 in the method embodiment of Figure 8a the steps 804, 806, 807, and 809 in the method embodiment of Figure 9a the steps 902 and 904 in the method embodiment of

[0277] In one embodiment, the communication unit 1003 is configured to send first information, the first information being used to indicate the terminal device to acquire multicast configuration information via a system message, the multicast configuration information being used to indicate the terminal device to receive a multicast service; and send the system message, the system message including the multicast configuration information.​

[0278] In a possible design, the terminal device is in an RRC idle state or an RRC inactive state.

[0279] In a possible design, the multicast configuration information includes a G-RNTI associated with the multicast service and an identifier of the multicast service.

[0280] In a possible design, the first information is carried in a paging message.

[0281] In a possible design, the paging message includes a paging record list, and the paging record list does not include the identifier of the terminal device.

[0282] In a possible design, the first information includes an identifier of the multicast service.

[0283] In a possible design, the first information is carried in first downlink control information, and the first downlink control information is used for scheduling the paging message.

[0284] In a possible design, the first information is first downlink control information, and the first downlink control information is used for scheduling the paging message; wherein the first downlink control information is scrambled by a first RNTI, and the first RNTI is different from a P-RNTI; or the first downlink control information is carried on a preset time-frequency resource.

[0285] In a possible design, the first information is carried in a downlink message in a random access procedure performed by the terminal device; wherein the downlink message is a contention resolution message; or the downlink message is second downlink control information, and the second downlink control information is used for scheduling the contention resolution message.

[0286] In a possible design, before the communication unit 1003 sends the first information, the communication unit 1003 is further configured to receive an identifier of the terminal device and / or an identifier of the multicast service sent by the terminal device; and the processing unit 1002 is configured to determine, according to the identifier of the terminal device and / or the identifier of the multicast service, that the terminal device needs to acquire the multicast configuration information.

[0287] In a possible design, before the communication unit 1003 sends the first information, the processing unit 1002 is further configured to determine that a number of RRC connections of the network device is greater than a first threshold.

[0288] It should be understood that the division of units in the above apparatus is only a logical functional division, and in actual implementation, all or part of the units can be integrated into one physical entity, or can be physically separated. The units in the apparatus can all be implemented in the form of software invoked by a processing element; or all be implemented in the form of hardware; or part of the units are implemented in the form of software invoked by a processing element, and part of the units are implemented in the form of hardware. For example, each unit can be a separately established processing element, or can be integrated in a chip of the apparatus, in addition, the unit can also be stored in the form of a program in a memory, and the function of the unit is invoked and executed by a processing element of the apparatus. In addition, all or part of the units can be integrated together, or can be independently implemented. The processing element described herein can be a processor, which can be an integrated circuit with a signal processing capability. In the implementation process, each step of the above method or each unit can be implemented by an integrated logic circuit of hardware in the processing element, or in the form of software invoked by the processing element.

[0289] In one example, the units in any of the above apparatuses can be one or more integrated circuits configured to implement the above method, for example, one or more application specific integrated circuits (ASICs), or one or more digital signal processors (DSPs), or one or more field programmable gate arrays (FPGAs), or a combination of at least two of these integrated circuit forms. For another example, when the units in the apparatus can be implemented in the form of a program invoked by a processing element, the processing element can be a processor, such as a general-purpose central processing unit (CPU), or other processor capable of invoking programs. For another example, the units can be integrated together to implement in the form of a system-on-a-chip (SOC).

[0290] The above receiving unit is an interface circuit of the apparatus for receiving signals from other apparatuses. For example, when the apparatus is implemented in the form of a chip, the receiving unit is an interface circuit of the chip for receiving signals from other chips or apparatuses. The above transmitting unit is an interface circuit of the apparatus for transmitting signals to other apparatuses. For example, when the apparatus is implemented in the form of a chip, the transmitting unit is an interface circuit of the chip for transmitting signals to other chips or apparatuses.

[0291] Please refer to Figure 11, which is a structural diagram of a terminal device provided in an embodiment of the present application. It can be the terminal device in the above embodiment, used to implement the operations of the terminal device in the above embodiment. Figure 11 As shown, the terminal device includes an antenna 1110, a radio frequency (RF) section 1120, and a signal processing section 1130. Antenna 1110 is connected to RF section 1120. In the downlink direction, RF section 1120 receives information sent by a network device via antenna 1110 and sends the information to signal processing section 1130 for processing. In the uplink direction, signal processing section 1130 processes the terminal device information and sends it to RF section 1120. RF section 1120 then processes the terminal device information and sends it to the network device via antenna 1110.

[0292] The signal processing unit 1130 may include a modem subsystem for processing data at various communication protocol layers; a central processing unit for processing the terminal device's operating system and application layers; and other subsystems, such as a multimedia subsystem for controlling the terminal device's camera and screen display, and a peripheral subsystem for connecting to other devices. The modem subsystem may be a separate chip.

[0293] The modem subsystem may include one or more processing elements 1131, such as a main control CPU and other integrated circuits. Furthermore, the modem subsystem may include a storage element 1132 and an interface circuit 1133. Storage element 1132 is used to store data and programs. However, the program used to execute the method performed by the terminal device in the above method may not be stored in storage element 1132 but rather in a memory external to the modem subsystem, and loaded by the modem subsystem when in use. Interface circuit 1133 is used to communicate with other subsystems.

[0294] The modem subsystem can be implemented using a chip comprising at least one processing element and an interface circuit, wherein the processing element is configured to execute each step of any of the methods performed by the terminal device described above, and the interface circuit is configured to communicate with other devices. In one implementation, the unit for implementing each step of the method described above can be implemented as a processing element scheduler. For example, the terminal device may include a processing element and a storage element, with the processing element invoking a program stored in the storage element to execute the method performed by the terminal device in the above method embodiments. The storage element can be a storage element located on the same chip as the processing element, i.e., an on-chip storage element.

[0295] In another implementation, the program for performing the method performed by the terminal device in the above method can be stored in a storage element which is different from the processing element, i.e., an off-chip storage element. At this time, the processing element calls or loads the program from the off-chip storage element to the on-chip storage element to call and perform the method performed by the terminal device in the above method embodiment.

[0296] In yet another implementation, the unit for implementing each step in the above method of the terminal device can be one or more processing elements which are configured on a modem subsystem. Here, the processing element can be an integrated circuit, such as one or more ASICs, or one or more DSPs, or one or more FPGAs, or a combination of these integrated circuit forms. These integrated circuits can be integrated together to form a chip.

[0297] The unit for implementing each step in the above method of the terminal device can be integrated together to form a SOC chip for implementing the above method. The chip can integrate at least one processing element and a storage element, and the method performed by the terminal device can be implemented in the form that the processing element calls the stored program of the storage element; or the chip can integrate at least one integrated circuit for implementing the method performed by the terminal device; or the functions of some units can be implemented in the form of calling programs by processing elements, and the functions of some units can be implemented in the form of integrated circuits.

[0298] It can be seen that the above apparatus for the terminal device can include at least one processing element and an interface circuit, wherein the at least one processing element is used to perform any of the methods performed by the terminal device provided in the above method embodiments. The processing element can perform part or all of the steps performed by the terminal device in the first way, i.e., by calling the program stored in the storage element; or in the second way, i.e., by the integrated logic circuit of the hardware in the processing element in combination with instructions; or in a combination of the first way and the second way.

[0299] Here, the processing element can be implemented by a processor, and the functions of the processing element can be the same as the functions of the processing unit described in Figure 10 For example, the processing element can be a general-purpose processor, such as a CPU, and can also be one or more integrated circuits configured to implement the above method, such as one or more ASICs, or one or more microprocessors DSPs, or one or more FPGAs, etc., or a combination of at least two of these integrated circuit forms. The storage element can be implemented by a memory, and the functions of the storage element can be the same as the functions of the storage unit described in Figure 12The storage units described in the above embodiments have the same function. The storage element can be implemented by a memory, and the function of the storage element can be the same as Figure 10 The storage units described in the above embodiments have the same function. The storage element can be implemented by a memory, and the function of the storage element can be the same as

[0300] Figure 11 The terminal device shown in the above embodiments can implement the method embodiments shown in Figure 7a , The terminal device shown in the above embodiments can implement the method embodiments shown in Figure 8a or Figure 9a The various processes of the terminal device involved in the method embodiments shown above. Figure 11 The operations and / or functions of the various modules in the terminal device shown above are respectively for implementing the corresponding processes in the method embodiments described above. For details, please refer to the description in the method embodiments described above, and the detailed description is appropriately omitted here to avoid repetition.

[0301] Please refer to Figure 12 , which is a structural schematic diagram of a network device provided by the embodiments of the present application. The network device is used to implement the operations of the network device in the above embodiments. As shown in Figure 12 , the network device includes an antenna 1201, a radio frequency device 1202, and a baseband device 1203. The antenna 1201 is connected to the radio frequency device 1202. In the uplink direction, the radio frequency device 1202 receives the information sent by the terminal device through the antenna 1201, and sends the information sent by the terminal device to the baseband device 1203 for processing. In the downlink direction, the baseband device 1203 processes the information of the terminal device and sends it to the radio frequency device 1202. The radio frequency device 1202 processes the information of the terminal device and sends it to the terminal device through the antenna 1201.

[0302] The baseband device 1203 can include one or more processing elements 12031, such as a master control CPU and other integrated circuits. In addition, the baseband device 1203 can further include a storage element 12032 for storing programs and data, and an interface 12033 for communicating information with the radio frequency device 1202, such as a common public radio interface (CPRI). The above apparatus for a network device can be located in the baseband device 1203, for example, the above apparatus for a network device can be a chip on the baseband device 1203, which includes at least one processing element and an interface circuit, wherein the processing element is configured to execute each step of any of the above methods performed by the network device, and the interface circuit is configured to communicate with other devices. In one implementation, the unit for implementing each step of the above method can be implemented in the form of a program scheduled by a processing element, for example, the apparatus for a network device includes a processing element and a storage element, and the processing element calls the program stored in the storage element to execute the method performed by the network device in the above method embodiments. The storage element can be a storage element on the same chip as the processing element, that is, an on-chip storage element, or a storage element on a different chip from the processing element, that is, an off-chip storage element.

[0303] In another implementation, the unit for implementing each step of the above method can be one or more processing elements configured on the baseband device, and the processing element can be an integrated circuit, such as one or more ASICs, or one or more DSPs, or one or more FPGAs, or a combination of these integrated circuits. These integrated circuits can be integrated together to form a chip.

[0304] The unit for implementing each step of the above method can be integrated together in the form of a system-on-a-chip (SOC), for example, the baseband device includes the SOC chip for implementing the above method. At least one processing element and a storage element can be integrated in the chip, and the method performed by the above network device can be implemented in the form of the processing element calling the program stored in the storage element; or at least one integrated circuit can be integrated in the chip for implementing the method performed by the above network device; or a combination of the above implementations can be used, part of the functions of the unit are implemented in the form of the processing element calling the program, and part of the functions of the unit are implemented in the form of the integrated circuit.

[0305] It can be seen that the apparatus for the network device can include at least one processing element and interface circuit, wherein the at least one processing element is configured to perform the method performed by any of the network devices provided by the above method embodiments. The processing element can execute part or all of the steps performed by the network device in the following two ways: one is to call the program stored in the storage element; the other is to execute part or all of the steps performed by the network device through the integrated logic circuit of the hardware in the processor element combined with the instructions; of course, part or all of the steps performed by the network device can also be executed in combination of the first way and the second way.

[0306] The processing element herein can be implemented by a processor as described above, and the function of the processing element can be the same as the function of the processing unit described in Figure 10 . For example, the processing element can be a general-purpose processor such as a CPU, and can also be one or more integrated circuits configured to implement the above method, such as one or more ASICs, or one or more microprocessors DSP, or one or more FPGAs, etc., or a combination of at least two of these integrated circuit forms. The storage element can be implemented by a memory, and the function of the storage element can be the same as the function of the storage unit described in Figure 12 . The storage element can be implemented by a memory, and the function of the storage element can be the same as the function of the storage unit described in Figure 10 . The storage element can be a memory, and can also be a collective term for a plurality of memories.

[0307] Figure 12 The network device shown can implement the processes related to the network device in the method embodiments shown in Figure 7a , Figure 8a or Figure 9a . Figure 12 The operations and / or functions of each module in the network device shown are respectively used to implement the corresponding processes in the above method embodiments. For details, please refer to the description in the above method embodiments, and the detailed description is appropriately omitted here.

[0308] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can be in the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can be in the form of a computer program product implemented on one or more computer usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer usable program code.

[0309] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more flowcharts and / or blocks in the flowcharts and / or blocks of the flowcharts. Figure 1 one or more flowcharts and / or blocks in the flowcharts and / or blocks of the flowcharts.

[0310] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instructions which implement the function specified in the flowchart block or blocks. Figure 1 one or more flowcharts and / or blocks in the flowcharts and / or blocks of the flowcharts. Figure 1 one or more flowcharts and / or blocks in the flowcharts and / or blocks of the flowcharts.

[0311] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more flowcharts and / or blocks in the flowcharts and / or blocks of the flowcharts. Figure 1 one or more flowcharts and / or blocks in the flowcharts and / or blocks of the flowcharts.

[0312] Obviously, numerous modifications and variations of the present application are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims and their equivalents, the application can be practiced otherwise than as specifically described.

Claims

1. A communication method characterized by comprising: Comprising: receiving first information from a network device, the first information being used to indicate a terminal device to acquire multicast configuration information through a system message, the multicast configuration information being used to indicate the terminal device to receive a multicast service; receiving the system message from the network device in a same system message modification period or a same frame or a same subframe or a same time slot or a same sub-time slot as where the first information is located, the system message comprising the multicast configuration information.

2. The method of claim 1, wherein, The terminal device is in a radio resource control (RRC) idle state or an RRC inactive state.

3. The method of claim 1, wherein, The multicast configuration information comprises a group-radio network temporary identifier (G-RNTI) associated with the multicast service and an identifier of the multicast service.

4. The method according to any one of claims 1 to 3, characterized in that, The first information is carried in a paging message from the network device.

5. The method of claim 4, wherein, The paging message comprises a paging record list, and the paging record list does not comprise an identifier of the terminal device.

6. The method of claim 4, wherein, The first information comprises an identifier of the multicast service.

7. The method according to any one of claims 1 to 3, characterized in that, The first information is carried in first downlink control information from the network device, the first downlink control information being used to schedule a paging message.

8. The method according to any one of claims 1 to 3, characterized in that, The first information is first downlink control information from the network device, the first downlink control information being used to schedule a paging message. The first downlink control information is scrambled by a first radio network temporary identifier (RNTI), and the first RNTI is different from a paging RNTI (P-RNTI); or the first downlink control information is transmitted through preset time-frequency resources.

9. The method according to any one of claims 1 to 3, characterized in that, The first information is carried in a downlink message in a random access procedure performed by the terminal device. The downlink message is a contention resolution message; or the downlink message is second downlink control information, the second downlink control information being used to schedule the contention resolution message.

10. The method of claim 9, wherein, The method further comprises: sending, to the network device, an identifier of the terminal device and / or an identifier of the multicast service in the random access procedure.

11. A communication method, comprising: Comprising: sending first information, the first information being used to indicate a terminal device to acquire multicast configuration information through a system message, the multicast configuration information being used to indicate the terminal device to receive a multicast service; sending the system message in a same system message modification period or a same frame or a same subframe or a same time slot or a same sub-time slot as where the first information is located, the system message comprising the multicast configuration information.

12. The method according to claim 11, characterized in that The terminal device is in a radio resource control (RRC) idle state or an RRC inactive state.

13. The method of claim 11, wherein, The multicast configuration information comprises a group-radio network temporary identifier (G-RNTI) associated with the multicast service and an identifier of the multicast service.

14. The method according to any one of claims 11 to 13, characterized in that, The first information is carried in a paging message.

15. The method of claim 14, wherein, The paging message comprises a paging record list, and the paging record list does not comprise an identifier of the terminal device.

16. The method of claim 14, wherein, The first information comprises an identifier of the multicast service.

17. The method of any one of claims 11-13, wherein, The first information is carried in first downlink control information, the first downlink control information being used to schedule a paging message.

18. The method of any one of claims 11-13, wherein, The first information is first downlink control information, the first downlink control information being used to schedule a paging message. The first downlink control information is scrambled by a first radio network temporary identifier (RNTI), and the first RNTI is different from a paging radio network temporary identifier (P-RNTI); or the first downlink control information is carried on preset time-frequency resources.

19. The method of any one of claims 11-13, wherein, The first information is carried in a downlink message in a random access procedure performed by the terminal device. The downlink message is a contention resolution message; or the downlink message is second downlink control information used for scheduling the contention resolution message.

20. The method of claim 19, wherein, Before the first information is sent, the method further includes: receiving an identifier of the terminal device and / or an identifier of the multicast service sent by the terminal device; determining, according to the identifier of the terminal device and / or the identifier of the multicast service, that the terminal device needs to acquire the multicast configuration information.

21. The method of any one of claims 11-13, wherein, Before the first information is sent, the method further includes: determining that a number of RRC connections is greater than a first threshold.

22. A communications device, characterized by The communication unit and the processing unit are included. The processing unit controls the communication unit to perform: receiving first information from a network device, the first information being used to indicate that the communication apparatus acquires multicast configuration information through a system message, the multicast configuration information being used to indicate that the communication apparatus receives a multicast service; and receiving, in a same system message modification period, a same frame, a same subframe, a same time slot or a same sub-time slot as where the first information is located, the system message from the network device, the system message including the multicast configuration information.

23. The apparatus of claim 22, wherein, The first information is carried in a paging message from the network device.

24. The apparatus of claim 22, wherein, The first information is carried in first downlink control information from the network device, the first downlink control information being used to schedule a paging message.

25. The apparatus of claim 22, wherein, The first information is carried in a downlink message in a random access procedure performed by the communication apparatus. The downlink message is a contention resolution message; or the downlink message is second downlink control information used for scheduling the contention resolution message.

26. A communications device, characterized by The communication unit and the processing unit are included. The processing unit controls the communication unit to perform: sending first information, the first information being used to indicate that a terminal device acquires multicast configuration information through a system message, the multicast configuration information being used to indicate that the terminal device receives a multicast service; and sending, in a same system message modification period, a same frame, a same subframe, a same time slot or a same sub-time slot as where the first information is located, the system message, the system message including the multicast configuration information.

27. The apparatus of claim 26, wherein, The first information is carried in a paging message.

28. The apparatus of claim 26, wherein, The first information is carried in first downlink control information, the first downlink control information being used to schedule a paging message.

29. The apparatus of claim 26, wherein, The first information is carried in a downlink message in a random access procedure performed by the terminal device. The downlink message is a contention resolution message; or the downlink message is second downlink control information used for scheduling the contention resolution message.

30. The apparatus of claim 29, wherein, The communication unit is further used to receive an identifier of the terminal device and / or an identifier of the multicast service sent by the terminal device. The processing unit is configured to determine, according to the identity of the terminal device and / or the identity of the multicast service, that the terminal device needs to acquire the multicast configuration information.

31. The apparatus of any one of claims 26-30, wherein, Before the communication unit transmits the first information, the processing unit is further configured to determine that the number of RRC connections is greater than a first threshold.

32. A communications device, characterized by A computer program product including a computer readable medium having stored thereon instructions that, when executed by a computer, cause the computer to perform the methods of any of claims 1-21.

33. A computer-readable storage medium, comprising: A computer program product including a computer readable medium having stored thereon instructions that, when executed by a computer, cause the computer to perform the methods of any of claims 1-21.

34. A computer program product, characterised in that, A computer program product including a computer readable medium having stored thereon instructions that, when executed by a computer, cause the computer to perform the methods of any of claims 1-21.

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