Information transmission method, information reception method, device and system

Abstract

An embodiment of the present invention provides an information transmitting method, an information receiving method, an apparatus and a system, which includes the steps of: a first terminal device establishing a connection with at least one second terminal device; and the first terminal device transmitting first identification information to a network device, the first identification information indicating a first identifier for the at least one second terminal device.

Description

[Technical Field]

[0001] The present invention relates to the field of communications. [Background technology]

[0002] In current communication networks, terminal devices access the network via a Uu interface and communicate with other terminal devices via a PC5 interface. Research into sidelink relay (SL relay) is currently underway in R17. Figure 1 is a schematic diagram illustrating sidelink relay scenarios. In scenario 1, a remote terminal device (remote UE) is not within the coverage area of ​​a base station or cell, and a relay terminal device (relay UE) is within the coverage area of ​​a base station or cell. In scenario 2, the remote terminal device and the relay terminal device are both within the coverage area of ​​a base station or cell. In scenario 3, the remote terminal device and the relay terminal device are within the coverage area of ​​different base stations or cells. Here, the Uu link of the relay UE uses NR (New Radio) Uu, and the PC5 interface between the relay UE and the remote UE uses NR sidelink.

[0003] The above description of the background art is merely for the purpose of explaining the configuration of the present invention more clearly and completely, and is provided for the understanding of those skilled in the art. These configurations described in the background art of the present invention should not be construed as being well known to those skilled in the art. Summary of the Invention [Problem to be solved by the invention]

[0004] To support SL relay communication, an adaptation layer is introduced in the R17 SL relay protocol stack, and an identifier for the remote terminal device and an identifier for its Uu radio bearer can be incorporated into the header of the adaptation layer so that the serving base station of the relay terminal device can identify the remote terminal device, but currently there is no resolved method for how to assign an identifier for the remote terminal device.

[0005] To solve at least one of the above problems or other similar problems, embodiments of the present invention provide an information transmitting method, an information receiving method, an apparatus and a system. [Means for solving the problem]

[0006] In one aspect of an embodiment of the present invention, there is provided an information receiving device configured in a first terminal device, the device including: a processing unit that establishes a connection with at least one second terminal device; a first transmitting unit that transmits first identification information to a network device, the first identification information indicating a first identifier for the at least one second terminal device; and a first receiving unit that receives second identification information transmitted by the network device, the second identification information indicating a second identifier for the at least one second terminal device.

[0007] In one aspect of an embodiment of the present invention, there is provided an information transmitting device to be applied to a network device, the device including: a third receiving unit that receives first identification information transmitted by a first terminal device, the first identification information indicating a first identifier for at least one second terminal device connected to the first terminal device; and a third transmitting unit that transmits second identification information to the first terminal device, the second identification information indicating a second identifier for at least one of the second terminal devices.

[0008] In one aspect of the embodiment of the present invention, there is provided a communication system including the network device according to the one aspect above and / or the first terminal device according to the one aspect above.

[0009] One of the advantageous effects of the embodiment of the present invention is as follows: An identifier of a second terminal device may be configured by a serving network device of a first terminal device, so that the first terminal device can use the identifier when forwarding data (such as RRC messages or user plane data) of the second terminal device, thereby easily realizing that the RRC messages and user plane data of the second terminal device are correctly identified by the network device.

[0010] As shown in the following description and drawings, specific embodiments of the present invention are disclosed in detail to illustrate ways in which the principles of the present invention can be employed. However, the scope of the present invention is not limited to these embodiments. The present invention encompasses all modifications, alterations, and equivalents within the spirit and scope of the appended claims.

[0011] Features described and / or shown in one embodiment may be used in the same or similar manner in one or more other embodiments, may be combined with features in other embodiments, or may be substituted for features in other embodiments.

[0012] It should be noted that in this text, the term "comprise / have" means the presence of a feature, element, step or component, and does not exclude the presence or addition of one or more other features, elements, steps or components. [Brief explanation of the drawings]

[0013] Elements and features depicted in one drawing and one embodiment of an example of the invention may be combined with elements and features shown in one or more drawings or embodiments, and in the drawings, like reference numerals may indicate corresponding elements in multiple drawings and may indicate corresponding elements used in more than one embodiment.

[0014] The drawings included are used to further understand the embodiments of the present invention, constitute a part of the specification, are used to illustrate the embodiments of the present invention, and together with the written description, explain the principles of the present invention. Note that the drawings described below are merely some examples of the present invention, and those skilled in the art can easily imagine other drawings based on these drawings. [Figure 1] 1 is a schematic diagram of an application scenario of a remote UE and a relay UE; [Figure 2] 2 to 4 are schematic diagrams of protocol stacks in a terminal device-network device relay scenario. [Figure 3] 2 to 4 are schematic diagrams of protocol stacks in a terminal device-network device relay scenario. [Figure 4] 2 to 4 are schematic diagrams of protocol stacks in a terminal device-network device relay scenario. [Figure 5] A schematic diagram of connection establishment for uplink and downlink transmission in a terminal device-network device relay scenario. [Figure 6] 1 is a schematic diagram of an information transmission method according to an embodiment of the present invention; [Figure 7] 1 is a schematic diagram of an information receiving method according to an embodiment of the present invention; [Figure 8] 8 to 11 are schematic diagrams of uplink and downlink transmission methods in a terminal device-network device relay scenario according to an embodiment of the present invention. [Figure 9] 8 to 11 are schematic diagrams of uplink and downlink transmission methods in a terminal device-network device relay scenario according to an embodiment of the present invention. [Figure 10] 8 to 11 are schematic diagrams of uplink and downlink transmission methods in a terminal device-network device relay scenario according to an embodiment of the present invention. [Figure 11] 8 to 11 are schematic diagrams of uplink and downlink transmission methods in a terminal device-network device relay scenario according to an embodiment of the present invention. [Figure 12] 1 is a schematic diagram of an information transmission method according to an embodiment of the present invention; [Figure 13] 1 is a schematic diagram of an information receiving method according to an embodiment of the present invention; [Figure 14] 1 is a schematic diagram of an information transmission and reception method according to an embodiment of the present invention; [Figure 15] 1 is a schematic diagram of an information transmission and reception method according to an embodiment of the present invention; [Figure 16] 1 is a schematic diagram of an information transmission method according to an embodiment of the present invention; [Figure 17] 17 and 18 are schematic diagrams of a switching method in a terminal device-network device relay scenario according to an embodiment of the present invention. [Figure 18] 17 and 18 are schematic diagrams of a switching method in a terminal device-network device relay scenario according to an embodiment of the present invention. [Figure 19] 1 is a schematic diagram of an information transmission method according to an embodiment of the present invention; [Figure 20] 1 is a schematic diagram of an information receiving method according to an embodiment of the present invention; [Figure 21] 1 is a schematic diagram of an information transmission and reception method according to an embodiment of the present invention; [Figure 22] 1 is a schematic diagram of an information receiving device according to an embodiment of the present invention; [Figure 23] 1 is a schematic diagram of an information receiving device according to an embodiment of the present invention; [Figure 24] 1 is a schematic diagram of an information transmission device according to an embodiment of the present invention; [Figure 25] 1 is a schematic diagram of an information transmitting and receiving device according to an embodiment of the present invention. [Figure 26]1 is a schematic diagram of an information transmitting and receiving device according to an embodiment of the present invention. [Figure 27] 1 is a schematic diagram of an information transmission device according to an embodiment of the present invention; [Figure 28] 1 is a schematic diagram of an information transmission device according to an embodiment of the present invention; [Figure 29] 1 is a schematic diagram of an information receiving device according to an embodiment of the present invention; [Figure 30] 1 is a schematic diagram of a communication system according to an embodiment of the present invention; [Figure 31] 1 is a schematic diagram of a terminal device according to an embodiment of the present invention; [Figure 32] FIG. 2 is a schematic diagram of a network device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0015] The above and other features of the present invention will become apparent from the following description. In the specification and drawings, specific embodiments of the present invention are disclosed in detail, and some of the embodiments in which the principles of the present invention can be adopted are shown. However, the present invention is not limited to the described embodiments. The present invention includes all modifications, variations, and equivalents within the scope of the appended claims. Below, various embodiments of the present invention will be described with reference to the drawings. These embodiments are merely illustrative and do not limit the present invention.

[0016] In embodiments of the present invention, the terms "first," "second," etc. are used in titles to distinguish between different elements, but do not represent the spatial arrangement or temporal order of these elements, and these elements are not limited to these terms. The term "and / or" includes any and all combinations of one or more of the terms listed in the associated list. The terms "comprise," "include," "have," etc. refer to the presence of listed features, elements, elements, or components, but do not exclude the presence or addition of one or more other features, elements, elements, or components.

[0017] In the embodiments of the present invention, the singular forms "one," "the," etc., include the plural and should be understood broadly as "one kind" or "one class," and are not limited to "one." Furthermore, the term "said" should be understood to include both the singular and the plural, unless the context clearly indicates otherwise. Furthermore, the term "described in" should be understood to mean "described at least in part," and the term "based on" should be understood to mean "based at least in part," unless the context clearly indicates otherwise.

[0018] In embodiments of the present invention, the terms "communication network" or "wireless communication network" may refer to a network conforming to any communication standard, such as, for example, Long Term Evolution (LTE), Long Term Evolution Advanced (LTE-A, LTE-Advanced), Wideband Code Division Multiple Access (WCDMA), High-Speed ​​Packet Access (HSPA), etc.

[0019] Additionally, communications between devices in a communications system may occur according to any stage of communications protocol, including, but not limited to, 1G (generation), 2G, 2.5G, 2.75G, 3G, 4G, 4.5G, and future 5G and 6G communications protocols, and / or other currently known or future developed communications protocols.

[0020] In an embodiment of the present invention, the term "network device" refers to a device in a communication system that allows a terminal device to access the communication system and provides a service to the terminal device, and may include, but is not limited to, a base station (BS), an access point (AP), a transmission reception point (TRP), a broadcast transmitter, a mobility management entity (MME), a gateway, a server, a radio network controller (RNC), a base station controller (BSC), etc.

[0021] Among them, the base station may include, but is not limited to, a Node B (NodeB or NB), an evolved Node B (eNodeB or eNB), a 5G base station (gNB), etc., as well as a remote radio head (RRH), a remote radio unit (RRU), a relay, or a low-power node (e.g., femto, pico, etc.). The term "base station" may include some or all of these functions, and each base station may provide communication coverage for a particular geographic area. The term "cell" may refer to a base station and / or its coverage area, depending on the context in which the term is used.

[0022] In the embodiments of the present invention, the term "User Equipment" (UE) or "Terminal Equipment" (TE) refers to a device that accesses a communication network and receives network services via, for example, a network device. The terminal device may be fixed or mobile, and may also be referred to as a mobile station (MS), a terminal, a subscriber station (SS), an access terminal (AT), a station, etc.

[0023] Among them, the terminal device may include, but is not limited to, a mobile phone, a personal digital assistant (PDA), a wireless modulation / demodulation device, a wireless communication device, a handheld device, a machine-type communication device, a laptop computer, a cordless phone, a smartphone, a smart watch, a digital camera, etc.

[0024] For example, in a scenario such as the Internet of Things (IoT), the user equipment may be a monitoring or measuring device or apparatus, including, but not limited to, a Machine Type Communication (MTC) terminal, an in-vehicle communication terminal, a Device to Device (D2D) terminal, a Machine to Machine (M2M) terminal, etc.

[0025] In an embodiment of the present invention, Relay UE refers to a relay-capable terminal device (UE-to-Network Relay UE) that can communicate directly with a network device, and Remote UE refers to a terminal device that needs to communicate with a network device via a Relay UE.

[0026] In an embodiment of the present invention, signaling radio bearers (SRBs) include SRB0, SRB1, SRB2, etc. Signaling radio bearers are radio bearers for transmitting RRC and NAS messages. SRB0 transmits RRC messages (e.g., RRC setup request, RRC setup, RRC reject, RRC re-establishment request, or RRC resume request) using a common control channel (CCCH) logical channel. SRB1 transmits RRC messages (which may include piggybacked NAS messages) and NAS messages before SRB2 establishment, and uses a dedicated control channel (DCCH) logical channel. SRB2 transmits RRC messages, including NAS messages and logged measurement messages, and uses the DCCH logical channel. SRB2 has a lower priority than SRB1 and may be configured by the network after access stratum (AS) security activation.

[0027] 2 and 3 are schematic diagrams of a control plane protocol stack in a Layer 2 UE-to-Network Relay scenario, and FIG. 4 is a schematic diagram of a user plane protocol stack in a Layer 2 UE-to-Network Relay scenario. Currently, the PC5 interface can support an adaptation layer (e.g., ADAPT in the figures), which is used only for bearer mapping. As shown in FIGS. 3 and 4, for the Uu interface, for uplink and downlink transmissions of a remote UE's non-SRB0 Uu radio bearer, the remote UE identifier and the Uu radio bearer identifier are included in the adaptation layer header. As shown in FIG. 2, for uplink and downlink transmissions of a remote UE to SRB0, the adaptation layer does not appear (apply) on the PC5 interface. For uplink and downlink transmissions of a remote UE to SRB0, the adaptation layer appears (applies) on the Uu interface. The protocol stacks in the PC5 interface of the Relay UE and Remote UE include a physical layer (PHY), a medium access control (MAC) layer above the PHY layer (providing packet filtering, logical channel priority processing, scheduling requests, data multiplexing and demultiplexing, mapping between logical channels and transmission channels, etc.), a radio link layer control protocol (RLC) layer above the MAC layer, and a radio resource control (PC5-RRC) layer above the RLC layer (RRC signaling interaction over the PC5 interface). Here, the PHY provides services to the MAC layer in the form of transmission channels, and the MAC layer provides services to the RLC layer in the form of logical channels. The Relay UE communicates with the gNB via the NR Uu interface protocol stack, and the non-access stratum (NAS) of the Remote UE peers with the NAS layer in the core network.

[0028] 5 is a schematic diagram of connection establishment for uplink and downlink transmission in a terminal device-network device relay scenario. As shown in FIG. 5, after a connection is established between a remote UE and a relay UE, the relay UE can establish an RRC connection with a network device to perform uplink and downlink transmission. Currently, the first RRC message sent by the remote UE (e.g., an RRC setup request, an RRC re-establishment request, or an RRC resume request) is carried by an SRB0. The SRB0 uses an adaptation layer on the Uu interface. An identifier for the remote terminal device can be added to the header of the adaptation layer so that the serving base station of the relay terminal device can identify the remote terminal device. However, there is currently no resolved method for allocating the identifier for the remote terminal device.

[0029] In an embodiment of the present invention, the remote terminal device needs to incorporate an identifier for the remote terminal device and an identifier for its Uu radio bearer into a header of the adaptation layer during either the initial access procedure or the handover procedure, so that the serving base station (initial access base station or target base station after handoff) of the relay terminal device can identify the remote terminal device. The following describes how to assign an identifier for the remote terminal device in the initial access procedure with reference to Examples 1 and 2, and how to assign an identifier for the remote terminal device in the handover procedure with reference to Examples 3 to 5.

[0030] Various embodiments of the present invention will now be described with reference to the drawings, which are merely illustrative and not limiting of the present invention.

[0031] Example 1 An embodiment of the present invention provides an information transmission method applied to a first terminal device side, where the first terminal device may be a Relay UE, and the second terminal device may be a Remote UE.

[0032] 6 is a schematic diagram of the information transmission method. As shown in FIG. 6, the method includes the following steps:

[0033] Step 601: The first terminal device establishes a connection with at least one second terminal device.

[0034] Step 602: The first terminal device sends first identification information to a network device, where the first identification information indicates a first identifier for the at least one second terminal device.

[0035] In some aspects, establishing a connection between a first terminal device and at least one second terminal device may include a process in which the second terminal device performs relay discovery, relay selection, or relay reselection, or a process in which a unicast link is established between the first terminal device and the second terminal device, where the connection is a PC5 connection or a sidelink (SL), such as a PC5-RRC connection, a PC5-AS (Access Stratum) connection, or a PC5 unicast link. The relay discovery process, the relay selection or relay reselection process, and the unicast link establishment process may refer to prior art, and descriptions thereof will be omitted here.

[0036] In some aspects, a first terminal device may establish a connection with one or more second terminal devices. Upon establishing a connection with each second terminal device, the first terminal device may obtain a first identifier for the second terminal device. The first identifier may be a destination identifier (ID) of the second terminal device, such as a layer-2 ID (L2 ID). Alternatively, to save overhead, the first identifier may be a first index having a length shorter than the length of the destination identifier to explicitly identify the second terminal device, and the first identifier may represent an identifier of communication on the PC5 interface of the second terminal device (communication with the first terminal device). And / or the first identification information may be an identification of a PC5 unicast link (PC5 unicast link ID) between the first terminal device and the second terminal device. For example, one or more PC5 unicast links may be established between a first terminal device and a second terminal device, and one PC5 unicast link ID uniquely identifies one PC5 unicast link corresponding to a destination identification or a first index of the second terminal device, i.e., implicitly indicates (the destination identifier or the first index of) the second terminal device. And / or, the first identification information may be an identifier (PC5-RRC connection ID) of a PC5-RRC connection between the first terminal device and the second terminal device. For example, one or more PC5 RRC connections may be established between the first terminal device and the second terminal device, and one PC5-RRC connection ID uniquely identifies a PC5-RRC connection corresponding to a destination identification or a first index of the second terminal device, i.e., implicitly indicates (the destination identifier or the first index of) the second terminal device. And / or, the first identifier may be a pair(s) of source layer-2 ID and destination L2 ID between the first terminal device and the second terminal device, such as a pair of the L2 ID of the first terminal device and the L2 ID of the second terminal device. This embodiment is not limited thereto.

[0037] For example, the first identifier may be carried by a sidelink signaling message or a sidelink RRC message between the first terminal device and the second terminal device. For example, the sidelink signaling message may be a discovery message, a direct communication request message, or a direct communication accept message, and the sidelink RRC message may be an RRC Reconfiguration Sidelink message or an RRC Reconfiguration Complete Sidelink message, examples of which are not described here. In some aspects, when a first index is used instead of transmitting a destination representation, the first terminal device or the second terminal device needs to further pre-allocate the first index. For the allocation of the first index, see Example 6, which is not described here.

[0038] In some aspects, the first identification information indicates a first identifier of one second terminal device that establishes a connection with the first terminal device, and the one second terminal device is a terminal device that newly establishes a connection with the first terminal device, or the first identification information indicates first identifiers of all second terminal devices that establish connections with the first terminal device. The method of transmitting the first identification information and the format will be described in detail in (1) and (2) below.

[0039] In some aspects, the method may further include the following steps:

[0040] Step 603: The first terminal device receives second identification information sent by the network device, where the second identification information indicates a second identifier of the at least one second terminal device.

[0041] In some aspects, upon receiving the first identification information, the network device may assign a second identifier based on the first identification information, generate the second identification information, and notify the first terminal device of the second identifier assigned to at least one second terminal device (known by the identification of the first identification information). The second identifier is a local / temporary identifier of the second terminal device. The local / temporary identifier may be included in a header of the adaptation layer of the Uu interface. The method and format of carrying the second identification information will be described in detail in (1) and (2) below.

[0042] In some aspects, the local / temporary identifier represents an identifier for communication over a Uu interface of the second terminal device and includes at least one of the following:

[0043] (1) A second index of a second terminal device, which is a second index for uniquely identifying a second terminal device having a connection relationship with a first terminal device. That is, the second index is unique within a second terminal device having a connection (for example, a PC5-RRC connection) with the first terminal device. For example, assuming that the first terminal device has connections with three second terminal devices, three second indexes may be adopted to identify these three second terminal devices, and one second index is used to identify one second terminal device, and may be represented by, for example, n bits, where n is 3 to 8, or may be represented by an integer (for example, any integer from 0 to 16).

[0044] (2) Cell Radio Network Temporary Identifier C-RNTI of the second terminal device (3) A part of the destination identifier of the second terminal device. For example, the destination identifier is represented by 24 bits, and the second identifier may be a part of the 24 bits, such as the upper X bits or the lower X bits, where the value of X may be an integer between 2 and 5, but this embodiment is not limited to this.

[0045] In some aspects, the network device may explicitly or implicitly indicate the correspondence between the first identifiers and the second identifiers so that the first terminal device can determine the correspondence between the first identifiers and the second identifiers, i.e., so that the first terminal device knows which second terminal devices (first identifiers) correspond to which second identifiers assigned by the network device. For example, the network device may transmit the second identification information and also transmit the first identifiers corresponding to at least one second identifier (explicit indication). Alternatively, the arrangement order of the second identifiers in the second identification information is the same as the appearance order of the first identifiers for at least one second terminal device in the first identification information (implicit indication). The appearance order of the first identifiers includes the appearance order in the same message or the appearance order in different messages. For example, if there are multiple second terminal devices connected to the first terminal device, the first identification information includes first identifiers for the multiple second terminal devices, and the order of appearance of the second identifiers corresponds one-to-one to the order of appearance of the first identifiers; or if the first identification information includes a first identifier for one second terminal device, and the first terminal device sends two or more uplink messages, and each uplink message carries one first identification, the order of appearance of the second identifiers corresponds to the order of receiving the multiple uplink messages, that is, corresponds one-to-one to the order of appearance of the first identifiers in each uplink message; or if the first identification information includes a first identifier for one second terminal device, and the network device assigns one second identifier each time it receives one first identifier, and the first terminal device transmits the next first identification after receiving one second identifier. The method of configuring the second identifier will be further described in (1) or (2) below.

[0046] In some aspects, the method may further include the following steps (not shown):

[0047] The first terminal device uses, stores, or maintains a correspondence between the first identifier and the second identifier.

[0048] For example, the first terminal device may determine which second terminal device (first identifier) ​​the second identifier assigned by the network device corresponds to based on the correspondence indicated explicitly or implicitly by the network device. After receiving the second identifier information, the first terminal device may use, store, or retain the correspondence between the first identifier and the second identifier, for example, for subsequent relay transmission of uplink and / or downlink data of the second terminal device.

[0049] In some aspects, as described below, the first terminal device may be in an RRC connected (RRC_CONNECTED) mode, or may be in an RRC idle mode (RRC_IDLE) or an RRC inactive (RRC_INACTIVE) mode.

[0050] (1) The first terminal device is in RRC connected mode In some aspects, since the first terminal device is in an RRC connected mode, the first terminal device may send an uplink message directly to the network device. In step 602, the uplink message may be used to carry the first identification information. For example, the uplink message may be a sidelink UE information (SUI) message. The following describes the SUI as an example, but the present invention is not limited thereto.

[0051] In some aspects, the first terminal device transmits the first identity to the network device when a first trigger condition is satisfied (in other words, the first terminal device transmits the SUI to the network device when a first trigger condition is satisfied). The first trigger condition includes at least one of the following: the first terminal device has established a connection with the second terminal device; a sidelink capability message has been transmitted between the first terminal device and the second terminal device; and the first terminal device has received a first RRC message for the second terminal device transmitted by the second terminal device.

[0052] For example, in the prior art, the transmission of an SUI message may be triggered when a sidelink service is of interest. In embodiments of the present invention, the transmission of an SUI message may be triggered when a first terminal device has established a connection with a second terminal device and / or when the first terminal device has sent a sidelink capability message to and from the second terminal device and / or when the first terminal device has received a first RRC message for the second terminal device sent by the second terminal device.

[0053] For example, sending of the SUI message may be triggered after the connection is established in step 601 (as described above).

[0054] Alternatively, after the connection is established, the transmission of the SUI message is triggered after sidelink capabilities are transmitted between the first terminal device and the second terminal device via a PC5-RRC message, where the first terminal device may notify the second terminal device of its sidelink capabilities and / or relay capabilities, and the second terminal device may notify the first terminal device of its sidelink capabilities and / or capabilities as a second terminal device.

[0055] Alternatively, after connection establishment, the first terminal device receives a first RRC message for the second terminal device transmitted by the second terminal device, triggering transmission of an SUI message. The first RRC message may be the first RRC message transmitted by the second terminal device to the first terminal device after connection establishment, or an RRC message transmitted using a specific SRB (e.g., SRB0), or an RRC message transmitted using a specific Layer 2 configuration (e.g., using a Layer 2 configuration corresponding to SRB0). The first RRC message for the second terminal device means that the RRC message is generated by the RRC of the second terminal device (for uplink), or received, analyzed, or processed by the RRC of the second terminal device (for downlink). For example, the first RRC message includes an RRC setup request, an RRC re-establishment request, or an RRC resume request message, but the present invention is not limited thereto.

[0056] If the trigger condition is met, the first terminal device may send an SUI including the first identification information to the network device in step 602. For example, the SUI may be expressed as follows using the data format of Abstract Syntax Notation ASN.1:

[0057] [Table 1] or

[0058] [Table 2] In the above aspect, the first identification information sl-RemoteUEList-r16 includes first identifiers (e.g., sl-DestinationIdentity-r16) for all second terminal devices with which a connection is currently established or a connection is newly established. The arrangement (appearance) order of the first identifiers may be arranged according to the chronological order in which the connections with the first terminal devices are established, but the embodiment of the present invention is not limited thereto.

[0059] For example, the SUI may be represented using the abstract syntax notation ASN.1 as follows:

[0060] [Table 3] In the above aspect, the first identification information SL-TxResourceReq-r16 includes first identifiers (e.g., sl-DestinationIdentity-r16) for all second terminal devices that have established a current connection or are establishing a new connection (e.g., sl-RemoteUE is used to indicate whether the destination ID corresponds to a remote terminal device, i.e., a second terminal device).

[0061] In some aspects, the second identification information may be carried by a fourth RRC message for the first terminal device in step 603. Being carried by the fourth RRC message for the first terminal device means being received, analyzed, or processed by the RRC of the first terminal device. For example, the fourth RRC message may include an RRC reconfiguration, an RRC re-establishment, or an RRC resume message.

[0062] In some aspects, the fourth RRC message may include second identities. The arrangement order of the second identifiers in the second identities is the same as the appearance order of the first identifiers for at least one second terminal device in the first identities. The appearance order of the first identifiers includes the appearance order in the same message or the appearance order in different messages. For example, when two or more second terminal devices are connected to the first terminal device, the first identities include first identifiers for the two or more second terminal devices, and the appearance order of the second identifiers corresponds one-to-one to the appearance order of the first identifiers. Alternatively, when the first identification information includes a first identifier for one second terminal device, and the first terminal device transmits two or more SUI messages, each carrying one first identification, the appearance order of the second identifiers corresponds to the order in which the two or more SUI messages are received, i.e., corresponds one-to-one to the appearance order of the first identifiers in each SUI message. This implicitly indicates the correspondence between the second identifier and the first identifier.

[0063] In some aspects, the fourth RRC message may indicate both the second identifier and the first identifier corresponding to the second identifier, thereby explicitly indicating the correspondence between the second identifier and the first identifier.

[0064] In some embodiments, after receiving the second identifier assigned by the network device, the first terminal device may add the second identifier to the header of the adaptation layer, details of which may refer to the prior art, and the information interaction process between the first terminal device, the second terminal device and the network device will be described in Example 2.

[0065] (2) The first terminal device is in RRC idle or inactive mode. In some aspects, when a first terminal device is in an RRC idle or inactive mode, after entering an RRC connected mode, it may transmit first identification information and receive second identification information using scheme (1). For example, the method may further include the first terminal device receiving a first RRC message for the second terminal device transmitted by the second terminal device and entering the RRC connected mode. After entering the RRC connected mode, the first terminal device may transmit first identification information and receive second identification information using scheme (1). For aspects of the first RRC message, reference may be made to (1), and description thereof will be omitted here.

[0066] In some aspects, as described below, when the first terminal device is in an RRC idle mode or an inactive mode, it may perform an RRC connection establishment procedure or an RRC resume procedure and transmit the first identification information in the RRC connection establishment procedure or the RRC resume procedure.

[0067] For example, in step 602, the first identification information may be carried using a second RRC message for the first terminal device, for example, the second RRC message for the first terminal device indicating that the RRC message is generated by the RRC of the first terminal device (for uplink) or is received, analyzed, or processed by the RRC of the first terminal device (for downlink). The second RRC message may be an RRC message that the first terminal device sends to the network device in its own RRC connection establishment procedure or RRC resumption procedure, including an RRC setup request, an RRC setup complete, an RRC resume request, or an RRC resume complete.

[0068] For example, in step 603, the second identification information may be carried by a third RRC message for the first terminal device. The third RRC message for the first terminal device is meant to be received or processed by the RRC of the first terminal device. For example, the third RRC message includes an RRC setup message, an RRC resume message, or an RRC reconfiguration message.

[0069] In some aspects, the third RRC message may include second identities. The arrangement order of the second identities in the second identities is the same as the appearance order of the first identities for at least one second terminal device in the first identities. The appearance order of the first identities includes the appearance order in the same second RRC message. For example, if there are two or more second terminal devices connected to the first terminal device, the first identities include first identities for the two or more second terminal devices, and the appearance order of the second identities corresponds one-to-one to the appearance order of the first identities. This implicitly indicates the correspondence between the second identities and the first identities.

[0070] In some aspects, the third RRC message may indicate both the second identifier and the first identifier corresponding to the second identifier, thereby explicitly indicating the correspondence between the second identifier and the first identifier.

[0071] For example, if the second RRC message is an RRC setup / resume request, the third RRC message may be an RRC setup / resume or an RRC reconfiguration. Alternatively, if the second RRC message is an RRC setup / resume complete, the third RRC message may be an RRC reconfiguration. Here, a description of such an example will be omitted.

[0072] In some embodiments, after receiving the second identifier assigned by the network device, the first terminal device may add the second identifier to the header of the adaptation layer, details of which may refer to the prior art, and the information interaction process between the first terminal device, the second terminal device and the network device will be described in Example 2.

[0073] According to this embodiment, the identifier of the second terminal device can be configured by the serving network device of the first terminal device, and the first terminal device can use the identifier when forwarding data of the second terminal device (e.g., RRC messages or user plane data, etc.), so that the RRC messages and user plane data of the second terminal device can be easily identified by the network device.

[0074] <Example 2> An embodiment of the present invention provides an information receiving method, which is applied to a network device side.

[0075] 7 is a schematic diagram of the information receiving method. As shown in FIG. 7, the method includes the following steps:

[0076] Step 701: A network device receives first identification information transmitted by a first terminal device, the first identification information indicating a first identifier for at least one second terminal device connected to the first terminal device.

[0077] In some aspects, the aspect of step 701 corresponds to step 602 in Example 1, and the first identifier, the method of conveying the first identification information, and the format thereof may refer to Example 1, and the description thereof will be omitted here.

[0078] In some aspects, the method may further include the following steps:

[0079] Step 702: The network device sends second identification information to the first terminal device, where the second identification information indicates a second identifier for at least one of the second terminal devices.

[0080] In some aspects, the aspect of step 702 corresponds to step 603 in Example 1, and the second identifier, the method and format of conveying the second identification information, etc. may refer to Example 1, and the description thereof will be omitted here.

[0081] In some aspects, the method may further include the step (not shown) of the network device using or storing a correspondence between the first identifier and the second identifier. Alternatively, the network device may use or store a correspondence between the first identifier, the second identifier, and the assigned C-RNTI.

[0082] 8 to 11 are schematic diagrams of uplink and downlink transmission methods in a terminal device-network device relay scenario according to an embodiment of the present invention, which will be described below with reference to FIGS.

[0083] 8 is a schematic diagram of a method in which a first terminal device is in an RRC connected mode. As shown in FIG. 8, the method includes the following steps:

[0084] Step 801: A first terminal device and a second terminal device establish a connection.

[0085] Step 802: The second terminal device sends a first RRC message to the first terminal device (e.g., sends the first RRC message using a default Layer 2 configuration on the PC5 interface) and establishes a connection with the network device via the first terminal device.

[0086] Step 803: If a first trigger condition is met, trigger sending of an SUI.

[0087] Step 804: The first terminal device sends an SUI to the network device, where the SUI carries the first identification information.

[0088] Step 805: The network device sends a fourth RRC message to the first terminal device, where the fourth RRC message carries the second identification information.

[0089] Step 806: The first terminal device forwards a first RRC message to the network device, including the second identifier in the header of the adaptation layer.

[0090] Step 807: If the network device accepts the connection establishment request of the second terminal device, it returns an RRC setup message (fifth RRC message) for the second terminal device to the first terminal device, which message includes a second identifier in the adaptation layer header and may preferably further include the C-RNTI of the second terminal device.

[0091] Step 808: The first terminal device forwards an RRC setup message to the second terminal device (for example, forwards the fifth RRC message using the default Layer 2 configuration on the PC5 interface).

[0092] Step 809: Transmit and receive uplink and / or downlink radio bearer data between the second terminal device and the network device via the first terminal device. Here, the uplink and / or downlink radio bearer data may be transmitted and / or received using a source Layer 2 or destination Layer 2 identifier at the PC5 interface. The bearer identifier may be included in an adaptation layer header file at the PC5 interface. At the Uu interface, the uplink and / or downlink radio bearer data includes the second identifier and the Uu radio bearer identifier in the adaptation layer header at the Uu interface. This allows the network device to identify the second terminal device, i.e., determine which second terminal device the uplink and downlink transmissions correspond to.

[0093] 9 is a schematic diagram of a method when a first terminal device is in an RRC idle or inactive mode. As shown in FIG. 9, the method includes the following steps:

[0094] Step 901: A first terminal device and a second terminal device establish a connection.

[0095] Step 902: The second terminal device sends a first RRC message to the first terminal device (e.g., sends the first RRC message using a default Layer 2 configuration on the PC5 interface) and establishes a connection with the network device via the first terminal device.

[0096] Step 903: The first terminal device performs its own RRC connection establishment procedure or RRC resume procedure to enter the RRC connection mode. For details, please refer to the prior art, and the description thereof will be omitted here.

[0097] Step 904: If a first trigger condition is met, trigger sending of an SUI.

[0098] Step 905: The first terminal device sends an SUI to a network device, where the SUI carries first identification information.

[0099] Step 906: The network device sends a fourth RRC message to the first terminal device, where the fourth RRC message carries the second identification information.

[0100] Step 907: The first terminal device forwards a first RRC message to the network device, where the second identifier is included in the header of the adaptation layer.

[0101] Step 908: If the network device accepts the connection establishment request of the second terminal device, it returns an RRC setup message (fifth RRC message) for the second terminal device to the first terminal device, which message includes a second identifier in the adaptation layer header and may preferably further include the C-RNTI of the second terminal device.

[0102] Step 909: The first terminal device forwards an RRC setup message to the second terminal device (for example, forwards the fifth RRC message using the default Layer 2 configuration on the PC5 interface).

[0103] Step 910: Transmit and receive uplink and / or downlink radio bearer data between the second terminal device and the network device via the first terminal device. Here, the uplink and / or downlink radio bearer data may be transmitted and / or received using source Layer 2 and destination Layer 2 identifiers at the PC5 interface. The bearer identifier may be included in an adaptation layer header file of the PC5 interface. At the Uu interface, the uplink and / or downlink radio bearer data includes the second identifier and the Uu radio bearer identifier of the second terminal device in the adaptation layer header of the Uu interface. This allows the network device to identify the second terminal device, i.e., determine which second terminal device the uplink and downlink transmissions correspond to.

[0104] 10 is a schematic diagram of a method when a first terminal device is in an RRC idle or inactive mode. As shown in FIG. 10, the method includes the following steps:

[0105] Step 1001: A first terminal device and a second terminal device establish a connection.

[0106] Step 1002: The second terminal device sends a first RRC message to the first terminal device (e.g., sends the first RRC message using a default Layer 2 configuration on the PC5 interface) and establishes a connection with the network device via the first terminal device.

[0107] Step 1003: The first terminal device performs its own RRC connection establishment procedure or RRC resume procedure, and sends a second RRC message to the network device, where the second RRC message carries the first identification information, and the second RRC message is an RRC setup request message or an RRC resume request message.

[0108] Step 1004: After receiving the second RRC message, the network device sends a third RRC message to the third first terminal device, where the third RRC message carries second identification information, and the third RRC message is an RRC setup message or an RRC resume message.

[0109] Step 1005: The first terminal device sends its RRC setup complete message or RRC resume complete message to the network device to complete its RRC connection procedure or RRC resume procedure.

[0110] Step 1006: The network device sends an RRC reconfiguration message to the first terminal device.

[0111] Step 1007: The first terminal device forwards a first RRC message to the network device, where the second identifier is included in the header of the adaptation layer.

[0112] Step 1008: If the network device accepts the connection establishment request of the second terminal device, it returns an RRC setup message (fifth RRC message) for the second terminal device to the first terminal device, which message includes a second identifier in the adaptation layer header and preferably may further include the C-RNTI of the second terminal device.

[0113] Step 1009: The first terminal device forwards an RRC setup message for the second terminal device to the second terminal device (e.g., forwards the fifth RRC message using the default Layer 2 configuration on the PC5 interface).

[0114] Step 1010: Transmit and receive uplink and / or downlink radio bearer data between the second terminal device and the network device via the first terminal device. Here, the uplink and / or downlink radio bearer data may be transmitted and / or received using source Layer 2 and destination Layer 2 identifiers at the PC5 interface. The bearer identifier may be included in an adaptation layer header file of the PC5 interface. At the Uu interface, the uplink and / or downlink radio bearer data includes the second identifier and the Uu radio bearer identifier of the second terminal device in the adaptation layer header of the Uu interface. This allows the network device to identify the second terminal device, i.e., determine which second terminal device the uplink and downlink transmissions correspond to.

[0115] 11 is a schematic diagram of a method when a first terminal device is in an RRC idle or inactive mode. As shown in FIG. 11, the method includes the following steps:

[0116] Step 1101: A first terminal device and a second terminal device establish a connection.

[0117] Step 1102: The second terminal device sends a first RRC message to the first terminal device (e.g., sends the first RRC message using a default Layer 2 configuration on the PC5 interface) and establishes a connection with the network device via the first terminal device.

[0118] Step 1103: The first terminal device performs its own RRC connection establishment procedure or RRC resume procedure, and sends an RRC setup / resume request message about itself to the network device.

[0119] Step 1104: After receiving the RRC setup / resume request message, the network device sends an RRC setup / resume message for the first terminal device to the first terminal device.

[0120] Step 1105: The first terminal device sends a second RRC message to the network device, where the second RRC message carries the first identification information, and the second RRC message is an RRC setup / resume complete message.

[0121] Step 1106: The network device sends a third RRC message to the first terminal device, where the third RRC message carries the second identification information, and the third RRC message is an RRC reconfiguration message.

[0122] Step 1107: The first terminal device forwards a first RRC message to the network device, where the second identifier is included in the header of the adaptation layer.

[0123] Step 1108: If the network device accepts the connection establishment request of the second terminal device, it returns an RRC setup message (fifth RRC message) for the second terminal device to the first terminal device, which message includes a second identifier in the adaptation layer header and may preferably further include the C-RNTI of the second terminal device.

[0124] Step 1109: The first terminal device forwards an RRC setup message for the second terminal device to the second terminal device (e.g., forwards the fifth RRC message using the default Layer 2 configuration on the PC5 interface).

[0125] Step 1110: Transmit and receive uplink and / or downlink radio bearer data between the second terminal device and the network device via the first terminal device. Here, the uplink and / or downlink radio bearer data may be transmitted and / or received using source Layer 2 and destination Layer 2 identifiers at the PC5 interface. The bearer identifier may be included in an adaptation layer header file of the PC5 interface. At the Uu interface, the uplink and / or downlink radio bearer data includes the second identifier and the Uu radio bearer identifier of the second terminal device in the adaptation layer header of the Uu interface. This allows the network device to identify the second terminal device, i.e., determine which second terminal device the uplink and downlink transmissions correspond to.

[0126] In the above aspects, the aspects of steps 801 to 805, 901 to 905, 1001 to 1005, and 1101 to 1105 may refer to Example 1. Furthermore, step 802 may be performed before step 803, after step 803, or after step 804 or 805, and the embodiments of the present invention are not limited to these.

[0127] According to this embodiment, the identifier of the second terminal device can be configured by the serving network device of the first terminal device, and the first terminal device can use the identifier when forwarding data of the second terminal device (e.g., RRC messages or user plane data, etc.), so that the RRC messages and user plane data of the second terminal device can be easily identified by the network device.

[0128] The above describes how to assign an identifier for a remote terminal device in an initial access procedure with reference to Examples 1 and 2. The following describes how to assign an identifier for a remote terminal device in a handover procedure with reference to Examples 3 to 5. In the handover procedure, the second identifier may be configured or reconfigured by a network device.

[0129] Example 3 An embodiment of the present invention provides an information transmission method, which is applied to a network device.

[0130] 12 is a schematic diagram of the information transmission method. As shown in FIG. 12, the method includes the following steps:

[0131] Step 1201: The network device determines to switch the second terminal device to be connected to the network device via the first terminal device.

[0132] Step 1202: The network device sends second identification information to the first terminal device, where the second identification information indicates a second identifier of the second terminal device.

[0133] In some aspects, in step 1201, the switching of the second terminal device includes a first switching or a second switching. The first switching refers to a switching from the second terminal device being connected to the source network device via the Uu interface (direct link) to the second terminal device being connected to the destination network device via the first terminal device (indirect link). The second switching refers to a switching from the second terminal device being connected to the source network device via the source first terminal device to the destination network device via the destination first terminal device (from indirect link to indirect link). The source network device and the destination network device may be the same or different, and embodiments of the present invention are not limited thereto. The network device's determination of whether / how the second terminal device switches may be based on a measurement report reported by the second terminal device. For specific details, reference may be made to the prior art, which is not described here.

[0134] In some aspects, for the switching, in step 1202, the network device may allocate a new second identifier for the second terminal device and notify the first terminal device (target first terminal device) of the newly allocated second identifier. The meaning of the second identifier may refer to Example 1. For example, the second identification information may be carried through a first RRC reconfiguration message, in which case the first terminal device and the second terminal device may or may not establish a connection, as will be described below.

[0135] (1) The connection between the first terminal device and the second terminal device is not established before the switchover. In this aspect, the network device may transmit the second identification information to the first terminal device before the switching of the second terminal device is completed. Because the connection between the first terminal device and the second terminal device is not established at the time of switching, the first terminal device does not know the first identifier for the second terminal device, and therefore does not know which second terminal device the assigned second identification corresponds to. In this aspect, the method may further include the following steps (not shown):

[0136] The network device transmits the second identification information to the second terminal device.

[0137] In this aspect, the network device may convey the second identifier information sent to the second terminal device through the second RRC reconfiguration message, so that the first terminal device and the network device can determine the correspondence between the first identifier and the second identifier during or after a subsequent procedure in which the first terminal device and the second terminal device establish a connection. That is, the method may further include the following steps (not shown):

[0138] After the first terminal device and the second terminal device establish a connection, the network device receives the first identification information sent by the first terminal device and the corresponding second identification information, where the first identification information indicates a first identifier for the second terminal device. The meaning of the first identifier may refer to the first embodiment.

[0139] In this aspect, a first terminal device and a second terminal device establish a connection, and the first terminal device may determine a correspondence relationship between a second identifier and a first identifier (specifically, this will be described in Example 4). The first terminal device may transmit the first identifier information and the corresponding second identifier information to the network device. The method may further include a step in which the network device uses or stores the correspondence relationship between the first identifier and the second identifier.

[0140] In some aspects, the first identity and the corresponding second identity may be carried in an SUI message, e.g., a newly added information element sl-RemoteUEList-r16 in the SUI, e.g., the newly added information element includes the first and second identities, or may be included in a sidelink failure information element sl-FailureList-r, or in a sidelink transmission resource request information element SL-TxResourceReq-r16.

[0141] For example, if the sidelink failure information element sl-FailureList-r16 is included, when a first terminal device detects a sidelink radio link failure between itself and a second terminal device and transmits an SUI, the network device can identify which second terminal device has experienced a sidelink radio link identification (SL RLF) with the first terminal device, and can stop data transmission to the second terminal device via the first terminal device, thereby saving overhead.

[0142] (2) The connection between the first terminal device and the second terminal device is established before the switchover. In this aspect, since the connection between the first terminal device and the second terminal device is already established at the time of switching, i.e., the first terminal device already knows the first identifier for the second terminal device, in this aspect the method may further include the following steps (not shown):

[0143] After the first terminal device and the second terminal device establish a connection, the network device receives first identification information sent by the second terminal device, which indicates a first identifier for the second terminal device.

[0144] In this aspect, the second terminal device may carry the first identification information in the measurement report message. In other words, before the switching, the network device already knows the first identifier for the second terminal device, so in step 1202, the network device notifies the first terminal device of both the second identification information and the first identifier corresponding to the second identification. That is, the first RRC reconfiguration message indicates the first identifier corresponding to the second identifier in addition to carrying the second identification information. That is, the method may further include a step (not shown) in which the network device uses or stores a correspondence relationship between the first identifier and the second identifier. For a specific aspect, refer to Example 2, and description thereof will be omitted here.

[0145] According to this embodiment, the identifier of the second terminal device can be configured by the serving network device of the first terminal device, and the first terminal device can use the identifier when forwarding data of the second terminal device (e.g., RRC messages or user plane data, etc.), so that the RRC messages and user plane data of the second terminal device can be easily identified by the network device.

[0146] Example 4 An embodiment of the present invention provides an information receiving method, which is applied to a first terminal device (hereinafter referred to as a target first terminal device) side.

[0147] 13 is a schematic diagram of the information receiving method. As shown in FIG. 13, the method includes the following steps:

[0148] Step 1301: A first terminal device receives second identification information sent by a network device, the second identification information indicating a second identifier of a second terminal device, and the second terminal device decides to switch to be connected to the network device via the first terminal device.

[0149] In some aspects, step 1301 corresponds to aspects of step 1202, and the description thereof will be omitted here.

[0150] (1) The connection between the first terminal device and the second terminal device is not established before the switchover. In some aspects, in step 1301, the second identification information may be conveyed via a first RRC reconfiguration message.

[0151] In some aspects, the method may further include the following steps:

[0152] The first terminal device receives the second identification information transmitted by the second terminal device.

[0153] For example, the second identification information transmitted by the second terminal device may be carried in a sidelink signaling (PC5-S) message or a sidelink RRC (PC5-RRC) message between the first terminal device and the second terminal device, and the sidelink signaling (PC5-S) message or the sidelink RRC (PC5-RRC) message may indicate the first identifier, for example, the first identifier may be explicitly included in the message or may be implicitly indicated via a lower layer (e.g., MAC layer and / or physical layer).

[0154] For example, the sidelink signaling message may be a discovery message, a direct communication request message, or a direct communication accept message, and the sidelink RRC message may be an RRCReconfigurationSidelink message or an RRCReconfigurationCompleteSidelink message. The above messages may be transmitted during or after the second terminal device and the first terminal device perform a relay discovery, relay selection, or relay reselection, or a PC5 unicast link establishment procedure. In other words, when the first identity and the second identity are indicated via a sidelink signaling message or a sidelink RRC message between the first terminal device and the second terminal device, after the first terminal device and the second terminal device establish a connection, the first terminal device may determine a correspondence relationship between the second identity and the first identity.

[0155] In some aspects, after the first terminal device and the second terminal device establish a connection, the method may further include the following steps.

[0156] The first terminal device transmits first identification information and corresponding second identification information to the network device. The first identification information indicates a first identifier related to the second terminal device. The meaning of the first identifier may refer to the first embodiment.

[0157] In other words, the first terminal device may determine the correspondence between the second identifier and the first identifier, and then transmit the first identification information and the corresponding second identification information to the network device. The method may further include a step (not shown) in which the first terminal device uses or stores the correspondence between the first identifier and the second identifier. For specific aspects, refer to Example 2, and the description thereof will be omitted here.

[0158] In some aspects, the first identification information and the corresponding second identification information sent by the first terminal device may be carried by an SUI message. For specific aspects, refer to Example 3, and the description thereof will be omitted here.

[0159] (2) The connection between the first terminal device and the second terminal device is established before the switchover. In this aspect, since a connection has been established between the first terminal device and the second terminal device at the time of switching, in other words, the first terminal device already knows the first identifier of the second terminal device (specifically, refer to Example 1). Therefore, in this aspect, in step 1301, the second identifier and the corresponding first identifier are simultaneously indicated by the first RRC reconfiguration message, and the first terminal device may determine a correspondence relationship between the second identifier and the first identifier after receiving the first RRC reconfiguration message. The method may further include a step (not shown) in which the first terminal device uses or stores the correspondence relationship between the first identifier and the second identifier. A specific aspect may refer to Example 2, and description thereof will be omitted here.

[0160] According to this embodiment, the identifier of the second terminal device can be configured by the serving network device of the first terminal device, and the first terminal device can use the identifier when forwarding data of the second terminal device (e.g., RRC messages or user plane data, etc.), so that the RRC messages and user plane data of the second terminal device can be easily identified by the network device.

[0161] <Example 5> An embodiment of the present invention provides an information transmission and reception method, which is applied to a second terminal device side.

[0162] 14 is a schematic diagram of the information transmission and reception method. As shown in FIG. 14, the method includes any one of the following steps:

[0163] Step 1401: The second terminal device sends first identification information to a network device, where the first identification information indicates a first identifier for the second terminal device.

[0164] Step 1402: The second terminal device receives second identification information sent by a network device, where the second identification information indicates a second identifier of the second terminal device.

[0165] In some aspects, the aspects of steps 1401 and 1402 may refer to the third or fourth embodiment, and the description thereof will be omitted here.

[0166] (1) The connection between the first terminal device and the second terminal device is not established before the switchover. 15 is a schematic diagram of the information transmission and reception method. As shown in FIG. 15, the method includes the following steps:

[0167] Step 1501: The second terminal device receives second identification information sent by a network device, where the second identification information indicates a second identifier of the second terminal device.

[0168] Step 1502: The second terminal device sends the second identification information to the first terminal device.

[0169] In some aspects, in step 1501, the second identification information may be carried via a second RRC reconfiguration message, for example, an RRC reconfiguration message (e.g., a switching command) including information on switching to the target first terminal device. This aspect may refer to Example 3, and description thereof will be omitted here.

[0170] In some aspects, in step 1502, the second identification information is carried in a sidelink signaling message or a sidelink RRC message between the first terminal device and the second terminal device, and the sidelink signaling message or the sidelink RRC message indicates the first identifier. This aspect may refer to Example 4, and description thereof will be omitted here.

[0171] (2) The connection between the first terminal device and the second terminal device is established before the switchover. 16 is a schematic diagram of the information transmission method. As shown in FIG. 16, the method includes the following steps:

[0172] Step 1601: The second terminal device sends first identification information to a network device, where the first identification information indicates a first identifier for the second terminal device.

[0173] In some aspects, in step 1601, the first identification information may be carried via a measurement report message, specifically see Example 3.

[0174] The following describes a switching method, taking switching from a direct link to an indirect link as an example, with reference to FIGS.

[0175] 17 is a schematic diagram of a method when a connection between the first terminal device and the second terminal device has not been established before switching. As shown in FIG. 17, the method includes the following steps:

[0176] Step 1701: A (target) network device sends a measurement configuration to a second terminal device.

[0177] Step 1702: The second terminal device performs measurements based on the measurement configuration and reports a measurement report, which may include at least one candidate first terminal device identifier (Relay UE ID), a serving cell of the first terminal device, and sidelink measurement results.

[0178] Step 1703: The network device determines, based on the measurement report, to switch the second terminal device to connect to the network device through the first terminal device.

[0179] Step 1704: The network device sends a first RRC reconfiguration message to the first terminal device for switching the second terminal device, the message including second identification information and Uu and PC5 RLC configurations and bearer mapping configurations for relaying. The first terminal device completes the RLC configurations and bearer mapping configurations of the corresponding PC5 and Uu interfaces based on the first RRC reconfiguration message.

[0180] Step 1705: The first terminal device sends an RRC reconfiguration complete message (corresponding to step 1704) to the network device. For details, refer to the prior art.

[0181] Step 1706: The network device sends a second RRC reconfiguration message for the second terminal device to the second terminal device, such as a switching command to connect to the network device via the first terminal device. The message includes second identification information, an identifier (Relay UE ID) of the first terminal device, a PC5 RLC configuration of the relay service, and an associated end-to-end radio bearer configuration. The second terminal device determines via which first terminal device to switch to connect to the network device based on the second RRC reconfiguration message.

[0182] Step 1707: The second terminal device and the first terminal device establish a connection. A specific example may refer to Example 1. For example, during or after the connection establishment process, the second identification information is carried by a sidelink signaling message or a sidelink RRC message between the first terminal device and the second terminal device. The sidelink signaling (PC5-S) message or the sidelink RRC (PC5-RRC) message further indicates the first identifier.

[0183] Step 1708 (optional): The first terminal device transmits the first identity and the corresponding second identity to the network device. For example, the first identity and the corresponding second identity are carried using an SUI, which is not described here. If the first identity and the corresponding second identity sent by the first terminal device to the network device are included in the sidelink failure information element sl-FailureList-r16 of the SUI message, this step is executed when a sidelink radio link failure is detected.

[0184] Step 1709: The first terminal device uses or stores the correspondence between the first identifier and the second identifier.

[0185] Step 1710: The second terminal device sends an RRC reconfiguration complete message to the network device via the first terminal device (corresponding to step 1706).

[0186] Step 1711 (optional): The switching of the second terminal device is completed, and uplink and / or downlink radio bearer data is transmitted and received between the second terminal device and the network device via the first terminal device. Here, in the PC5 interface, the uplink and / or downlink radio bearer data may be transmitted and / or received using a source Layer 2 or destination Layer 2 identifier. The bearer identifier may be included in the header file of the adaptation layer of the PC5 interface. In the Uu interface, the uplink and / or downlink radio bearer data includes the second identifier and the Uu radio bearer identifier of the second terminal device in the header of the adaptation layer of the Uu interface. This allows the network device to identify the second terminal device, i.e., determine which second terminal device the uplink and downlink transmissions correspond to.

[0187] 18 is a schematic diagram of a method when a connection between a first terminal device and a second terminal device is established before switching. As shown in FIG. 18, the method includes the following steps:

[0188] Step 1801: The second terminal device and the first terminal device establish a connection.

[0189] Step 1802: The (target) network device sends a measurement configuration to the second terminal device.

[0190] Step 1803: The second terminal device performs measurements based on the measurement configuration and reports a measurement report, which may include at least one candidate first terminal device identifier (Relay UE ID), a serving cell of the first terminal device, and a sidelink measurement result, and may further include first identification information.

[0191] Step 1804: The network device determines, based on the measurement report, to switch the second terminal device to connect to the network device through the first terminal device.

[0192] Step 1805: The network device sends a first RRC reconfiguration message for switching the second terminal device to the first terminal device. The message simultaneously indicates a second identifier and a first identifier corresponding to the second identifier (obtained based on step 1803), as well as Uu and PC5 RLC configurations and bearer mapping configurations for relaying. The first terminal device completes the RLC configurations and bearer mapping configurations of the corresponding PC5 and Uu interfaces based on the first RRC reconfiguration message.

[0193] Step 1806: The network device sends a second RRC reconfiguration message for the second terminal device to the second terminal device, the message including an identifier (Relay UE ID) of the first terminal device, a PC5 RLC configuration of the relay service, and a related end-to-end radio bearer configuration. Based on the second RRC reconfiguration message, the second terminal device determines through which first terminal device to connect to the network device.

[0194] Step 1807: The first terminal device uses or stores the correspondence between the first identifier and the second identifier.

[0195] Step 1808: The second terminal device sends an RRC reconfiguration complete message to the network device via the first terminal device (corresponding to step 1806).

[0196] Step 1809 (optional): The switching of the second terminal device is completed, and uplink and / or downlink radio bearer data is transmitted and received between the second terminal device and the network device via the first terminal device. Here, in the PC5 interface, the uplink and / or downlink radio bearer data may be transmitted and / or received using a source Layer 2 or destination Layer 2 identifier. The bearer identifier may be included in the header file of the adaptation layer of the PC5 interface. In the Uu interface, the uplink and / or downlink radio bearer data includes the second identifier and the Uu radio bearer identifier of the second terminal device in the header of the adaptation layer of the Uu interface. This allows the network device to identify the second terminal device, i.e., determine which second terminal device the uplink and downlink transmissions correspond to.

[0197] The execution order of the above steps 1709 and 1807 is not limited to this, and the embodiment of the present invention is not limited to this. Furthermore, although not shown, the network device side may use or store the correspondence relationship between the first identifier and the second identifier, and the description thereof will be omitted here.

[0198] According to this embodiment, the identifier of the second terminal device can be configured by the serving network device of the first terminal device, and the first terminal device can use the identifier when forwarding data of the second terminal device (e.g., RRC messages or user plane data, etc.), so that the RRC messages and user plane data of the second terminal device can be easily identified by the network device.

[0199] In this embodiment, to save transmission overhead, a first index having a length shorter than the destination identifier is transmitted instead of the destination identifier. The first index can uniquely identify the destination identifier. However, if a SL radio link failure (RLF) of a PC5 interface is detected, using the first index instead of the destination identifier prevents the network device from knowing the destination identifier of the second terminal device and therefore from identifying which SL of the PC5 interface detected the RLF. According to the information transmission method of the embodiment of the present invention, by carrying the first index and further carrying the second identifier or destination identifier in the information related to the side link failure transmitted by the first terminal device to the network device, the network device can accurately identify which SL of the PC5 interface detected the RLF. Below, Examples 6 to 8 are described.

[0200] Example 6 An embodiment of the present invention provides an information transmission method, which is applied to a first terminal device side.

[0201] 19 is a schematic diagram of the information transmission method. As shown in FIG. 19, the method includes the following steps:

[0202] Step 1901: A first terminal device transmits information regarding a sidelink failure to a network device, the information regarding the sidelink failure including a destination identifier of at least one second terminal device in which the sidelink failure has occurred, a second identifier of the second terminal device in which the sidelink failure has occurred and / or a first identifier related to the second terminal device in which the sidelink failure has occurred.

[0203] In some aspects, as described above, to save transmission overhead, a first index having a length shorter than the length of the destination identifier may be used for transmission instead of the destination identifier, but the destination identifier can be uniquely identified. For example, the first index may be assigned by the first terminal device or the second terminal device, and the first index may be notified to the first terminal device and / or the network device. If the first index is assigned by the first terminal device, the method may include the following steps:

[0204] The first terminal device assigns the first index and transmits second information indicating the first index to the second terminal device. For example, the second information may be carried by a sidelink signaling message or a sidelink RRC message. The sidelink signaling message or the sidelink RRC message has been described in the above embodiments, and therefore will not be described again here.

[0205] In some aspects, if the first index is assigned by the second terminal device, the method may further include the following steps.

[0206] The first terminal device receives first information indicating the first index assigned and transmitted by the second terminal device. For example, the first information may be carried by a sidelink signaling message or a sidelink RRC message. The sidelink signaling message or the sidelink RRC message has been described in the above embodiments, and therefore will not be described again here.

[0207] In some aspects, the method may further include the following steps:

[0208] The first terminal device transmits third information indicating the first index to the network device.

[0209] In some aspects, when a first terminal device detects a sidelink RLF of the PC5 interface, the first terminal device reports the sidelink RLF of the PC5 interface to a network device. For example, the first terminal device notifies the network device of the RLF detection using information related to the sidelink failure. The information related to the sidelink failure includes a destination identifier of at least one second terminal device in which the sidelink failure occurred, a second identifier of the second terminal device in which the sidelink failure occurred, and / or a first identifier associated with the second terminal device in which the sidelink failure occurred. The first identifier is a first index. The second identifier has been described above, and its description will be omitted here.

[0210] In some aspects, information related to the sidelink failure (e.g., sl-FailureList-r16) may be carried in the SUI. In the prior art, the sl-FailureList-r16 includes a destination identifier of at least one second terminal device where a sidelink failure occurred. In embodiments of the present invention, the sl-FailureList-r16 may include a first identifier, a second identifier, or both a first identifier and a second identifier.

[0211] According to this embodiment, by carrying the first index and further carrying the second identifier or destination identifier in the information related to the side link failure sent by the first terminal device to the network device, the network device can accurately identify which SL of the PC5 interface has detected the RLF.

[0212] Example 7 An embodiment of the present invention provides an information receiving method, which is applied to a network device side.

[0213] 20 is a schematic diagram of the information receiving method. As shown in FIG. 20, the method includes the following steps:

[0214] Step 2001: A network device receives information about a sidelink failure transmitted by a first terminal device, the information about the sidelink failure including a destination identifier of at least one second terminal device in which the sidelink failure has occurred, a second identifier of the second terminal device in which the sidelink failure has occurred and / or a first identifier related to the second terminal device in which the sidelink failure has occurred.

[0215] In some aspects, the aspect of step 2001 may refer to step 1901. The aspects of the first identifier and the second identifier are as described above, and the description thereof will be omitted here.

[0216] In some aspects, the method may further include the following steps:

[0217] The network device receives third information indicating the first index sent by the first terminal device so as to determine a first index assigned for the destination identifier by the first terminal device or the second terminal device.

[0218] According to this embodiment, by carrying the first index and further carrying the second identifier or destination identifier in the information related to the side link failure sent by the first terminal device to the network device, the network device can accurately identify which SL of the PC5 interface has detected the RLF.

[0219] Example 8 An embodiment of the present invention provides an information transmission and reception method, which is applied to a second terminal device side.

[0220] 21 is a schematic diagram of the information transmission and reception method. As shown in FIG. 21, the method includes the following steps:

[0221] Step 2101: A second terminal device assigns a first index and sends first information indicating the first index to the first terminal device, or the second terminal device receives second information indicating the first index sent by the first terminal device, where the first index corresponds to a destination identifier of the second terminal device.

[0222] In some aspects, the method may further include the following steps:

[0223] In some aspects, the network device receives third information indicating the first index transmitted by the first terminal device so as to determine a first index assigned for the destination identifier by the first terminal device or the second terminal device.

[0224] For example, the first information or the second information may be carried by a sidelink signaling message or a sidelink RRC message. As described in the above aspects, the aspect of the first index may refer to Example 6, and description thereof will be omitted here.

[0225] Although the above has outlined an embodiment of the present invention with reference to Figures 6 to 21, the present invention is not limited thereto. For example, the execution order of each operation may be appropriately adjusted, some other operations may be added, or some of these operations may be deleted. Those skilled in the art will be able to make appropriate modifications to the above content without being limited to the description of Figures 6 to 21.

[0226] The above-described embodiments are merely examples of the present invention, and the present invention is not limited thereto. Appropriate modifications may be made based on the above-described embodiments. For example, each of the above-described embodiments may be used alone, or one or more of the above-described embodiments may be used in combination. For example, in the case where the first identifier is a first index in the first to fifth embodiments, the first to fifth embodiments may be combined with the sixth to eighth embodiments.

[0227] Example 9 An embodiment of the present invention provides an information transmitting / receiving device, which is configured in a first terminal device.

[0228] 22 is a schematic diagram of an information receiving device according to an embodiment of the present invention. The embodiment of the present invention will be described from the perspective of a first terminal device. Here, the principle of implementation of the information receiving device according to the present invention is similar to the method of embodiment 1, so a description of the overlapping content will be omitted.

[0229] As shown in FIG. 22, an information receiving device 2200 according to an embodiment of the present invention includes the following units.

[0230] The processing unit 2201 establishes a connection with at least one second terminal device.

[0231] The first sending unit 2202 sends first identification information to the network device, the first identification information indicating a first identifier for the at least one second terminal device.

[0232] The first receiving unit 2203 receives second identification information transmitted by the network device, the second identification information indicating a second identifier of the at least one second terminal device.

[0233] In some aspects, the first identity is carried in an SUI or a second RRC message for the first terminal device.

[0234] In some aspects, when the first terminal device is in an RRC connected mode or when the first terminal device is in an RRC idle or inactive mode, the device further includes a second receiving unit (not shown, optional).

[0235] The second receiving unit receives a first RRC message for the second terminal device transmitted by the second terminal device and enters an RRC connected mode.

[0236] In some aspects, the second RRC message for the first terminal device includes an RRC setup request, or an RRC setup complete, or an RRC resume request, or an RRC resume complete.

[0237] In some aspects, the first RRC message for the second terminal device includes an RRC setup request, an RRC re-establishment request, or an RRC resume request message.

[0238] In some aspects, the first transmitter transmits first identification information to the network device when a first trigger condition is met, the first trigger condition including at least one of the first terminal device establishing a connection with the second terminal device, a sidelink capability message being transmitted between the first terminal device and the second terminal device, and the first terminal device receiving a first RRC message for the second terminal device transmitted by the second terminal device.

[0239] In some aspects, the first identifier is a destination ID or a first index, and / or an identifier of a PC5 unicast link, and / or an identifier of a PC5-RRC connection, and / or a source identifier and destination identifier pair.

[0240] In some aspects, the first identification information includes a first identifier for one second terminal device, which is a terminal device that newly establishes a connection with the first terminal device, or the first identification information includes first identifiers for all second terminal devices that establish a connection with the first terminal device.

[0241] In some aspects, the second identifier is a local / temporary identifier of the second terminal device.

[0242] In some aspects, the local / temporary identifier includes at least one of a second index of the second terminal device, the second index being for uniquely identifying the second terminal device having a connection relationship with the first terminal device, a C-RNTI of the second terminal device, and a portion of a destination identifier of the second terminal device.

[0243] In some aspects, the second identification information is carried by a fourth RRC message for the first terminal device or a third RRC message for the first terminal device, the fourth RRC message including an RRC reconfiguration, RRC re-establishment, or RRC resume message, and the third RRC message for the first terminal device including an RRC setup, RRC resume, or RRC reconfiguration.

[0244] In some aspects, the arrangement order of the second identifiers in the second identification information is the same as the appearance order of the first identifiers for the at least one second terminal device in the first identification information.

[0245] In some aspects, the third RRC message indicates the first identifier corresponding to the second identifier, and / or the fourth RRC message indicates the first identifier corresponding to the second identifier.

[0246] In some aspects, the device further includes a first storage unit (not shown, optional).

[0247] The first storage unit uses or stores the correspondence between the first identifier and the second identifier.

[0248] In some aspects, the apparatus further includes a second transmitter (not shown, optional).

[0249] The second transmitter transmits information about the sidelink failure to the network device, the information about the sidelink failure including a destination identifier of at least one second terminal device in which the sidelink failure occurred, a second identifier of the second terminal device in which the sidelink failure occurred, and / or a first identifier related to the second terminal device in which the sidelink failure occurred.

[0250] The aspects of the above-mentioned components may refer to the first embodiment, and the description of the overlapping contents will be omitted.

[0251] 23 is a schematic diagram of an information receiving device according to an embodiment of the present invention. The embodiment of the present invention will be described from the perspective of a first terminal device. Here, the principle of implementation of the information receiving device according to the present invention is similar to the method of embodiment 4, so a description of the overlapping content will be omitted.

[0252] As shown in FIG. 23, an information receiving device 2300 according to an embodiment of the present invention includes the following units.

[0253] The eleventh receiving unit 2301 receives second identification information transmitted by the network device, the second identification information indicating a second identifier of the second terminal device, and the second terminal device determines to switch to be connected to the network device via the first terminal device.

[0254] In some aspects, the apparatus further includes a twelfth receiver (not shown, optional).

[0255] The twelfth receiving unit receives the second identification information transmitted by the second terminal device.

[0256] In some aspects, the second identity transmitted by the second terminal device is carried in a sidelink signaling message or a sidelink RRC message between the first terminal device and the second terminal device, the sidelink signaling message or the sidelink RRC message indicating the first identifier.

[0257] In some aspects, the second identification information transmitted by the eleventh receiver is conveyed via a first RRC reconfiguration message.

[0258] In some aspects, the first RRC reconfiguration message indicates a first identification that corresponds to the second identifier.

[0259] In some aspects, the device further includes a fifth storage unit (not shown, optional).

[0260] The fifth storage unit uses or stores the correspondence between the first identifier and the second identifier.

[0261] In some aspects, the apparatus further includes a thirteenth transmitter unit (not shown, optional).

[0262] A thirteenth transmitting unit transmits the first identification information and the corresponding second identification information to the network device.

[0263] In some aspects, the first identification and the corresponding second identification are carried by an SUI.

[0264] In some aspects, the first identity and the corresponding second identity are newly added information elements in the SUI, or are included in a sidelink failure information element, or are included in a sidelink transmission resource request information element.

[0265] The aspects of the above-mentioned components may refer to the fourth embodiment, and the overlapping contents will not be described again.

[0266] 24 is a schematic diagram of an information transmission device according to an embodiment of the present invention. The embodiment of the present invention will be described from the perspective of a first terminal device. Here, the principle of implementation of the information transmission device according to the present invention is similar to the method of embodiment 6, so a description of the overlapping content will be omitted.

[0267] As shown in FIG. 24, an information transmitting device 2400 according to an embodiment of the present invention includes the following units.

[0268] The fourth transmitter 2401 transmits information about the sidelink failure to the network device, the information about the sidelink failure including a destination identifier of at least one second terminal device in which the sidelink failure occurred, a second identifier of the second terminal device in which the sidelink failure occurred, and / or a first identifier related to the second terminal device in which the sidelink failure occurred.

[0269] In some aspects, the second identifier is a local / temporary identifier of the second terminal device.

[0270] In some aspects, the local / temporary identifier includes at least one of a second index of the second terminal device, the second index being for uniquely identifying the second terminal device, a C-RNTI of the second terminal device, and a portion of a destination identifier of the second terminal device.

[0271] In some aspects, the first identifier is a first index of the second terminal device.

[0272] In some aspects, the apparatus further includes a fifth receiver (not shown, optional).

[0273] The fifth receiving unit receives first information indicating a first index assigned and transmitted by the second terminal device, or assigns the first index and transmits second information indicating the first index to the second terminal device.

[0274] In some aspects, the first information and / or the second information is carried by a PC5-RRC message or a PC5-S message.

[0275] The aspects of the above-mentioned components may refer to the sixth embodiment, and overlapping descriptions will be omitted.

[0276] Although the above description is limited to the components or modules related to the present invention, the present invention is not limited thereto. The information transmitting / receiving devices 2200, 2300, and 2400 according to the embodiments of the present invention may include other components or modules, and reference may be made to related art for specific details of these components or modules.

[0277] 22 to 24 only show exemplary connections or signal flows between the respective components or modules, but those skilled in the art may employ various related technologies such as bus connections. The various components or modules described above may be implemented by hardware devices such as a processor, memory, transmitter, and receiver, but the present invention is not limited to these.

[0278] Example 10 An embodiment of the present invention provides an information transmitting and receiving device, configured in a second terminal device.

[0279] 25 is a schematic diagram of an information receiving device according to an embodiment of the present invention. The embodiment of the present invention will be described from the perspective of a second terminal device. Here, the principle of implementation of the information transmitting device according to the present invention is similar to the method of embodiment 5, so a description of the overlapping content will be omitted.

[0280] The device includes a tenth transmitting unit 2501 and / or a tenth receiving unit 2502 .

[0281] The tenth transmitting unit 2501 transmits the first identification information to the network device, the first identification information indicating a first identifier for the second terminal device.

[0282] The tenth receiving unit 2502 receives second identification information transmitted by the network device, the second identification information indicating a second identifier of the second terminal device.

[0283] In some aspects, the apparatus further includes an eleventh transmitter unit (optional, not shown).

[0284] An eleventh transmitting unit transmits the second identification information to the first terminal device.

[0285] In some aspects, the second identity is carried in a sidelink signaling message or a sidelink RRC message between the first terminal device and the second terminal device, the sidelink signaling message or the sidelink RRC message indicating the first identifier.

[0286] In some aspects, the tenth receiver receives the second identity sent by the network device via a second RRC reconfiguration message.

[0287] In some aspects, the tenth transmitter transmits the first identification information to the network device via a measurement report message.

[0288] 26 is a schematic diagram of an information transmitting and receiving device according to an embodiment of the present invention. The embodiment of the present invention will be described from the perspective of a second terminal device. Here, the principle of implementation of the information transmitting device according to the present invention is similar to the method of embodiment 8, so a description of the overlapping content will be omitted.

[0289] The device includes a seventh transmitting unit 2601 or a seventh receiving unit 2602 . The seventh transmitter 2601 assigns a first index and transmits first information indicating the first index to the first terminal device. The seventh receiver 2602 receives second information indicating the first index transmitted by the first terminal device. The first index corresponds to the destination identifier of the second terminal device.

[0290] The aspects of the above-mentioned components may refer to the fifth or eighth embodiment, and overlapping descriptions will be omitted.

[0291] Although the above describes only the components or modules related to the present invention, the present invention is not limited to these. The information transmitting / receiving devices 2500 to 2600 according to the embodiments of the present invention may include other components or modules, and the specific contents of these components or modules may refer to the related art.

[0292] 25 and 26 only exemplify the connections or signal flows between the respective components or modules, but those skilled in the art may employ various related technologies such as bus connections. The various components or modules described above may be implemented by hardware devices such as a processor, memory, transmitter, and receiver, but the present invention is not limited to these.

[0293] Example 11 An embodiment of the present invention provides an information transmitting / receiving device, which is configured in a network device.

[0294] 27 is a schematic diagram of an information transmission device according to an embodiment of the present invention. The embodiment of the present invention will be described from the network device side. Here, the principle of implementation of the information transmission device according to the present invention is similar to the method of embodiment 2, so a description of the overlapping content will be omitted.

[0295] As shown in FIG. 27, an information transmitting device 2700 according to an embodiment of the present invention includes the following units.

[0296] The third receiving unit 2701 receives first identification information transmitted by a first terminal device, the first identification information indicating a first identifier of at least one second terminal device connected to the first terminal device.

[0297] The third transmitting unit 2702 transmits second identification information to the first terminal device, the second identification information indicating a second identifier for at least one second terminal device.

[0298] In some aspects, the first identity is carried in an SUI or a second RRC message for the first terminal device.

[0299] In some aspects, the second RRC message for the first terminal device includes an RRC setup request, or an RRC setup complete, or an RRC resume request, or an RRC resume complete.

[0300] In some aspects, when a first trigger condition is satisfied, the third receiver receives first identification information transmitted by a first terminal device, the first trigger condition including at least one of the first terminal device establishing a connection with the second terminal device, a sidelink capability message being transmitted between the first terminal device and the second terminal device, and the first terminal device receiving a first RRC message for the second terminal device transmitted by the second terminal device.

[0301] In some aspects, the first identifier is a destination ID or a first index.

[0302] In some aspects, the first identification information includes a first identifier for one second terminal device, which is a terminal device that newly establishes a connection with the first terminal device, or the first identification information includes first identifiers for all second terminal devices that establish a connection with the first terminal device.

[0303] In some aspects, the second identifier is a local / temporary identifier of the second terminal device.

[0304] In some aspects, the local / temporary identifier includes at least one of a second index of the second terminal device, the second index being for uniquely identifying the second terminal device having a connection relationship with the first terminal device, a C-RNTI of the second terminal device, and a portion of a destination identifier of the second terminal device.

[0305] In some aspects, the second identification information is carried by a fourth RRC message for the first terminal device or a third RRC message for the first terminal device, the fourth RRC message including an RRC reconfiguration, RRC re-establishment, or RRC resume message, and the third RRC message for the first terminal device including an RRC setup, RRC resume, or RRC reconfiguration.

[0306] In some aspects, the order of arrangement of the second identifiers in the second identification information is the same as the order of appearance of the first identifiers for the at least one second terminal device in the first identification information.

[0307] In some aspects, the third RRC message indicates the first identifier corresponding to the second identifier, and / or the fourth RRC message indicates the first identifier corresponding to the second identifier.

[0308] In some aspects, the device further includes a second storage unit (optional, not shown).

[0309] The second storage unit uses or stores the correspondence between the first identifier and the second identifier.

[0310] In some aspects, the device further includes a third storage unit (optional, not shown).

[0311] The third storage unit uses or stores the correspondence relationship between the first identifier, the second identifier, and the assigned C-RNTI.

[0312] In some aspects, the apparatus further includes a fourth receiver (optional, not shown).

[0313] The fourth receiver receives information about the sidelink failure transmitted by the first terminal device, the information about the sidelink failure including a destination identifier of at least one second terminal device in which the sidelink failure occurred, a second identifier of the second terminal device in which the sidelink failure occurred, and / or a first identifier related to the second terminal device in which the sidelink failure occurred.

[0314] The aspects of the above-mentioned components may refer to the second embodiment, and the overlapping contents will not be described again.

[0315] 28 is a schematic diagram of an information transmission device according to an embodiment of the present invention. The embodiment of the present invention will be described from the network device side. Here, the principle of implementation of the information transmission device according to the present invention is similar to the method of embodiment 3, so a description of the overlapping content will be omitted.

[0316] As shown in FIG. 28, an information transmitting device 2800 according to an embodiment of the present invention includes the following units.

[0317] The decision unit 2801 decides to switch so that the second terminal device is connected to the network device via the first terminal device.

[0318] The eighth transmitter 2802 transmits second identification information to the first terminal device, the second identification information indicating a second identifier of the second terminal device.

[0319] In some aspects, the apparatus further includes a ninth transmitter unit (optional, not shown).

[0320] A ninth transmitter transmits the second identification information to the second terminal device.

[0321] In some aspects, the apparatus further includes an eighth receiver (optional, not shown).

[0322] The eighth receiving unit receives, after the first terminal device and the second terminal device establish a connection, the first identification information transmitted by the first terminal device and the corresponding second identification information, where the first identification information indicates a first identifier for the second terminal device.

[0323] In some aspects, the device further includes a fourth storage unit (optional, not shown).

[0324] The fourth storage unit uses or stores the correspondence between the first identifier and the second identifier.

[0325] In some aspects, the second identification information transmitted by the eighth transmitter is carried in a first RRC reconfiguration message.

[0326] In some aspects, the second identification information transmitted by the eighth transmitter is carried in a second RRC reconfiguration message.

[0327] In some aspects, the apparatus further includes a ninth receiver (optional, not shown).

[0328] The ninth receiving unit receives first identification information transmitted by the second terminal device after the first terminal device and the second terminal device establish a connection, the first identification information indicating a first identifier for the second terminal device.

[0329] In some aspects, the first identification information is carried in a measurement report message.

[0330] In some aspects, the first RRC reconfiguration message indicates a first identifier that corresponds to the second identifier.

[0331] In some aspects, the first identity and the corresponding second identity are carried by an SUI.

[0332] In some aspects, the first identity and the corresponding second identity are newly added information elements in the SUI, or are included in a sidelink failure information element, or are included in a sidelink transmission resource request information element.

[0333] The aspects of the above-mentioned components may refer to the third embodiment, and the overlapping contents will not be described again.

[0334] 29 is a schematic diagram of an information receiving device according to an embodiment of the present invention. The embodiment of the present invention will be described from the network device side. Here, the principle of implementation of the information receiving device according to the present invention is similar to the method of embodiment 7, so the overlapping content will not be described.

[0335] As shown in FIG. 29, an information receiving device 2900 according to an embodiment of the present invention includes the following units.

[0336] The sixth receiver 2901 receives information about a sidelink failure transmitted by a first terminal device, the information about the sidelink failure including a destination identifier of at least one second terminal device in which a sidelink failure has occurred, a second identifier of the second terminal device in which the sidelink failure has occurred, and / or a first identifier related to the second terminal device in which the sidelink failure has occurred.

[0337] In some aspects, the second identifier is a local / temporary identifier of the second terminal device.

[0338] In some aspects, the local / temporary identifier includes at least one of a second index of the second terminal device, the second index being for uniquely identifying the second terminal device, a C-RNTI of the second terminal device, and a portion of a destination identifier of the second terminal device.

[0339] In some aspects, the first identifier is a first index of the second terminal device.

[0340] In some aspects, the first index is assigned by the first terminal device or assigned by the second terminal device.

[0341] The aspects of the above-mentioned components may refer to the seventh embodiment, and the overlapping contents will not be described again.

[0342] Although the above describes only the components or modules related to the present invention, the present invention is not limited to these. The information transmitting / receiving devices 2700 to 2900 according to the embodiments of the present invention may include other components or modules, and the specific contents of these components or modules may refer to the related art.

[0343] 27 to 29 only exemplify the connections or signal flows between the respective components or modules, but those skilled in the art may employ various related technologies such as bus connections. The various components or modules described above may be implemented by hardware devices such as a processor, memory, transmitter, and receiver, but the present invention is not limited to these.

[0344] Example 12 An embodiment of the present invention provides a communication system. Figure 30 is a schematic diagram of a communication system according to an embodiment of the present invention. As shown in Figure 30, the communication system includes a network device 3001, a first terminal device 3002, and at least one second terminal device 3003.

[0345] In some aspects, the network device 3001 is configured to execute the method performed by the network device according to Example 2, Example 3, or Example 7, and may include any of the devices in FIGS. 27 to 29. In some aspects, the first terminal device 3002 is configured to execute the method according to Example 1, Example 4, or Example 6, and may include any of the devices in FIGS. 22 to 24. In some aspects, the second terminal device 3003 is configured to execute the method according to Example 5 or Example 8, and may include any of the devices in FIGS. 25 and 26.

[0346] Moreover, the embodiment of the present invention further provides a terminal device.

[0347] 31 is a schematic diagram showing a terminal device according to an embodiment of the present invention. As shown in FIG. 31, the terminal device 3100 may include a processor 3101 and a memory 3102. The memory 3102 stores data and programs and is connected to the processor 3101. Note that this diagram is for illustrative purposes only, and other types of structures may be used to supplement or replace this structure to realize communication functions or other functions.

[0348] For example, the processor 3101 may be configured to execute a program to implement the method described in any one of the first, fourth to sixth, or eighth embodiments.

[0349] As shown in Fig. 31, the terminal device 3100 may further include a communication module 3103, an input unit 3104, a display 3105, and a power supply 3106. Here, the functions of each of the above units are the same as those of the prior art, and therefore, description thereof will be omitted here. Note that the terminal device 3100 does not need to include all of the units shown in Fig. 31. Furthermore, the terminal device 3100 may further include units not shown in Fig. 31, and prior art may be referred to.

[0350] An embodiment of the present invention further provides a network device.

[0351] Fig. 32 is a schematic diagram showing a network device according to an embodiment of the present invention. As shown in Fig. 32, a network device 3200 may include a processor (central processing unit: CPU) 3201 and a memory 3202, and the memory 3202 is connected to the processor 3201. The memory 3202 may store various types of data, and may further store a data processing program and execute the program under the control of the processor 3201.

[0352] For example, the processor 3201 may be configured to execute a program to implement the method described in the second, third or seventh embodiment.

[0353] 32, the network device 3200 may further include a transceiver 3203 and an antenna 3204. The functions of the above components are similar to those of the prior art, and a description thereof will be omitted here. The network device 3200 does not need to include all the units shown in FIG. 32. The network device 3200 may further include units not shown in FIG. 32, and prior art may be referred to.

[0354] An embodiment of the present invention further provides a computer-readable program, which, when executed on a terminal device, causes a computer to execute the methods described in the above embodiments 1, 4 to 6, and 8 on the terminal device.

[0355] An embodiment of the present invention further provides a storage medium having a computer-readable program stored thereon, the program, when executed, causing a computer to perform the method described in the above embodiment 1, 4 to 6, or 8 on a terminal device.

[0356] In an embodiment of the present invention, there is further provided a computer-readable program, which, when executed in a network device, causes a computer to perform the method described in the above embodiment 2, 3 or 7 in the network device.

[0357] An embodiment of the present invention further provides a storage medium having a computer-readable program stored thereon, the program, when executed, causing a computer to perform the method described in the above embodiment 2, 3 or 7 in a network device.

[0358] The above-described apparatus and methods of the present invention may be realized by hardware or a combination of hardware and software. The present invention relates to a computer-readable program that, when executed by a logic unit, causes the logic unit to implement the above-described apparatus or components, or to implement the above-described various methods or steps. The logic unit may be, for example, a field programmable logic unit, a microprocessor, or a processor used in a computer. The present invention also relates to a storage medium for storing the above-described program, for example, a hard disk, a magnetic disk, an optical disk, a DVD, a flash memory, etc.

[0359] Each processing method in each device described with reference to the embodiments of the present invention may be implemented by hardware, a software module executed by a processor, or a combination of both. For example, one or more of the functional block diagrams shown in the drawings, or one or more combinations of the functional block diagrams, may correspond to each software module in a computer program flow or each hardware module. These software modules may correspond to each step shown in the drawings. These hardware modules may be implemented by implementing these software modules in hardware, for example, using a field programmable gate array (FPGA).

[0360] The software module may be located in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, mobile hard disk, CD-ROM, or any other form of storage medium known to those skilled in the art. The storage medium may be connected to the processor so that the processor reads information from or writes information to the storage medium, or the storage medium may be a component of the processor. The processor and the storage medium may be located in an ASIC. The software module may be stored in the memory of the mobile terminal or in a memory card inserted into the mobile terminal. For example, if a device (e.g., a mobile terminal) uses a relatively large-capacity MEGA-SIM card or a large-capacity flash memory device, the software module may be stored in the MEGA-SIM card or the large-capacity flash memory device.

[0361] One or more functional blocks and / or one or more combinations of functional blocks in the functional block diagrams set forth in the figures may be implemented with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, or any suitable combination thereof to perform the functions described herein. One or more functional blocks and / or one or more combinations of functional blocks in the functional block diagrams set forth in the figures may be implemented with, for example, a combination of computing devices, such as a combination of a DSP and a microprocessor, a combination of multiple microprocessors, one or more microprocessors in combination with a DSP communication, or any other configuration.

[0362] Although the present invention has been described above with reference to specific embodiments, the above description is merely illustrative and does not limit the scope of protection of the present invention. Various modifications and changes may be made to the present invention without departing from the spirit and principles of the present invention, and these modifications and changes are also within the scope of the present invention.

[0363] Furthermore, the following supplementary notes are disclosed regarding the embodiments including the above examples. (Appendix 1) An information receiving method applied to a first terminal device, comprising: a first terminal device establishing a connection with at least one second terminal device; a step of the first terminal device transmitting first identification information to a network device, the first identification information indicating a first identifier for the at least one second terminal device. (Appendix 2) The method of claim 1, wherein the first identification information is carried by an SUI or a second RRC message for the first terminal device. (Appendix 3) The first terminal device is in an RRC connected mode, or The method described in Supplementary Note 1, further comprising the step of: when the first terminal device is in an RRC idle or inactive mode, the first terminal device receiving a first RRC message for the second terminal device sent by the second terminal device and entering an RRC connected mode. (Appendix 4) The method of claim 2, wherein the second RRC message for the first terminal device includes an RRC setup request, an RRC setup complete, an RRC resume request, or an RRC resume complete. (Appendix 5) The method described in Supplementary Note 3, wherein the first RRC message for the second terminal device includes an RRC setup request, an RRC re-establishment request, or an RRC resume request message. (Appendix 6) If a first trigger condition is satisfied, the first terminal device sends first identification information to the network device; The first trigger condition is: the first terminal device has established a connection with the second terminal device; a sidelink capability message is transmitted between the first terminal device and the second terminal device; and A method as described in any of Supplementary Notes 1 to 5, including at least one of the following: the first terminal device receives a first RRC message for the second terminal device sent by the second terminal device. (Appendix 7) 7. A method according to any one of Supplementary Notes 1 to 6, wherein the first identifier is a destination identifier (destination ID) or a first index, and / or an identifier of a PC5 unicast link, and / or an identifier of a PC5-RRC connection, and / or a pair of a source identifier and a destination identifier. (Appendix 8) A method according to any one of appendices 1 to 7, wherein the first identification information includes a first identifier for one second terminal device, the one second terminal device being a terminal device that newly establishes a connection with the first terminal device, or the first identification information includes first identifiers for all second terminal devices that establish a connection with the first terminal device. (Appendix 9) 9. The method of any of Supplementary Notes 1 to 8, further comprising a step of the first terminal device receiving second identification information transmitted by the network device, the second identification information indicating a second identifier of the at least one second terminal device. (Appendix 10) 10. The method of claim 9, wherein the second identifier is a local / temporary identifier of the second terminal device. (Appendix 11) The local / temporary identifier is: a second index of the second terminal device, the second index being for uniquely identifying the second terminal device having a connection relationship with the first terminal device; the C-RNTI of the second terminal device, and 11. The method of claim 10, including at least one portion of the destination identifier of the second terminal device. (Appendix 12) 12. The method of claim 9, 10, or 11, wherein the second identification information is carried by a fourth RRC message for the first terminal device or a third RRC message for the first terminal device, the fourth RRC message including an RRC reconfiguration, an RRC re-establishment, or an RRC resume message, and the third RRC message for the first terminal device including an RRC setup, an RRC resume, or an RRC reconfiguration. (Appendix 13) A method according to any one of appendices 9 to 12, wherein the order of arrangement of second identifiers in the second identification information is the same as the order of appearance of first identifiers for the at least one second terminal device in the first identification information. (Appendix 14) 13. The method of claim 12, wherein the third RRC message indicates the first identifier corresponding to the second identifier, and / or the fourth RRC message indicates the first identifier corresponding to the second identifier. (Appendix 15) 15. The method of any one of appendices 1 to 14, further comprising a step in which the first terminal device uses or stores a correspondence between the first identifier and the second identifier. (Appendix 16) 16. The method of any one of Supplementary Notes 1 to 15, further comprising a step in which the first terminal device sends information about a sidelink failure to the network device, the information about the sidelink failure including a destination identifier of at least one second terminal device in which a sidelink failure has occurred, a second identifier of the second terminal device in which the sidelink failure has occurred and / or a first identifier related to the second terminal device in which the sidelink failure has occurred. (Appendix 17) An information transmission method applied to a network device, comprising: A method comprising: a step in which the network device receives first identification information transmitted by a first terminal device, the first identification information indicating a first identifier for at least one second terminal device connected to the first terminal device. (Appendix 18) 18. The method of claim 17, wherein the first identification information is carried by an SUI or a second RRC message for the first terminal device. (Appendix 19) The method of claim 2, wherein the second RRC message for the first terminal device includes an RRC setup request, an RRC setup complete, an RRC resume request, or an RRC resume complete. (Appendix 20) When a first trigger condition is satisfied, the network device receives first identification information sent by a first terminal device; The first trigger condition is: the first terminal device has established a connection with the second terminal device; a sidelink capability message is transmitted between the first terminal device and the second terminal device; and A method according to any one of Supplementary Notes 17 to 19, including at least one of the following: the first terminal device receives a first RRC message for a second terminal device sent by the second terminal device. (Appendix 21) 21. A method according to any one of Supplementary Notes 17 to 20, wherein the first identifier is a destination identifier (destination ID) or a first index, and / or an identifier of a PC5 unicast link, and / or an identifier of a PC5-RRC connection, and / or a pair of a source identifier and a destination identifier. (Appendix 22) A method according to any one of appendices 17 to 21, wherein the first identification information includes a first identifier for one second terminal device, the one second terminal device being a terminal device that newly establishes a connection with the first terminal device, or the first identification information includes first identifiers for all second terminal devices that establish a connection with the first terminal device. (Appendix 23) 23. The method of any of Supplementary Notes 17 to 22, further comprising a step of the network device sending second identification information to the first terminal device, the second identification information indicating a second identifier for at least one of the second terminal devices. (Appendix 24) 24. The method of claim 23, wherein the second identifier is a local / temporary identifier of the second terminal device. (Appendix 25) The local / temporary identifier is: a second index of the second terminal device, the second index being for uniquely identifying the second terminal device having a connection relationship with the first terminal device; the C-RNTI of the second terminal device, and 25. The method of claim 24, including at least one portion of the destination identifier of the second terminal device. (Appendix 26) 26. The method of claim 23, 24, or 25, wherein the second identification information is carried by a fourth RRC message for the first terminal device or a third RRC message for the first terminal device, the fourth RRC message including an RRC reconfiguration, RRC re-establishment, or RRC resume message, and the third RRC message for the first terminal device including an RRC setup, RRC resume, or RRC reconfiguration. (Appendix 27) A method according to any one of appendices 23 to 25, wherein the order of arrangement of second identifiers in the second identification information is the same as the order of appearance of first identifiers for the at least one second terminal device in the first identification information. (Appendix 28) 27. The method of claim 26, wherein the third RRC message indicates the first identifier corresponding to the second identifier, and / or the fourth RRC message indicates the first identifier corresponding to the second identifier. (Appendix 29) 29. The method of any of claims 17 to 28, further comprising the step of the network device using or storing a correspondence between the first identifier and the second identifier. (Appendix 30) 29. The method of any of Supplementary Notes 17 to 28, further comprising the step of the network device using or storing a correspondence between the first identifier, the second identifier and the assigned C-RNTI. (Appendix 31) 31. The method of any of Supplementary Notes 17 to 30, further comprising: a step of receiving, by the network device, information regarding the sidelink failure transmitted by the first terminal device, wherein the information regarding the sidelink failure includes a destination identifier of at least one second terminal device in which a sidelink failure has occurred, a second identifier of the second terminal device in which the sidelink failure has occurred and / or a first identifier related to the second terminal device in which the sidelink failure has occurred. (Appendix 32) An information transmission method applied to a first terminal device, comprising: a step in which the first terminal device transmits information regarding the sidelink failure to a network device, the information regarding the sidelink failure including a destination identifier of at least one second terminal device in which the sidelink failure occurred, a second identifier of the second terminal device in which the sidelink failure occurred and / or a first identifier related to the second terminal device in which the sidelink failure occurred. (Appendix 33) 33. The method of claim 32, wherein the second identifier is a local / temporary identifier of the second terminal device. (Appendix 34) The local / temporary identifier is: a second index of the second terminal device, the second index being for uniquely identifying the second terminal device; the C-RNTI of the second terminal device, and 34. The method of claim 33, including at least one portion of the destination identifier of the second terminal device. (Appendix 35) 33. The method of claim 32, wherein the first identifier is a first index of the second terminal device. (Appendix 36) The method described in Supplementary Note 35, further comprising a step in which the first terminal device receives first information indicating a first index assigned and transmitted by the second terminal device, or the first terminal device assigns the first index and transmits second information indicating the first index to the second terminal device. (Appendix 37) 37. The method of claim 36, wherein the first information and / or the second information is carried by a PC5-RRC message or a PC5-S message. (Appendix 38) An information receiving method applied to a network device, comprising: a step of receiving, by the network device, information regarding a sidelink failure transmitted by a first terminal device, the information regarding the sidelink failure including a destination identifier of at least one second terminal device in which a sidelink failure has occurred, a second identifier of the second terminal device in which the sidelink failure has occurred and / or a first identifier related to the second terminal device in which the sidelink failure has occurred. (Appendix 39) 39. The method of claim 38, wherein the second identifier is a local / temporary identifier of the second terminal device. (Appendix 40) The local / temporary identifier is: a second index of the second terminal device, the second index being for uniquely identifying the second terminal device; the C-RNTI of the second terminal device, and 40. The method of claim 39, including at least one portion of the destination identifier of the second terminal device. (Appendix 41) 39. The method of claim 38, wherein the first identifier is a first index of the second terminal device. (Appendix 42) 42. The method of claim 41, wherein the first index is assigned by the first terminal device or assigned by the second terminal device. (Appendix 43) An information transmission method applied to a second terminal device, A method comprising a step in which the second terminal device assigns a first index and transmits first information indicating the first index to the first terminal device, or the second terminal device receives second information indicating the first index transmitted by the first terminal device, wherein the first index corresponds to a destination identifier of the second terminal device. (Appendix 44) An information transmission method applied to a network device, comprising: determining by the network device to switch the second terminal device to be connected to the network device via the first terminal device; a step of the network device transmitting second identification information to the first terminal device, the second identification information indicating a second identifier of the second terminal device. (Appendix 45) 45. The method of claim 44, further comprising the step of the network device transmitting the second identification information to the second terminal device. (Appendix 46) 46. ​​The method of claim 44 or 45, further comprising the step of: after the first terminal device and the second terminal device establish a connection, the network device receiving first identification information transmitted by the first terminal device and the corresponding second identification information, wherein the first identification information indicates a first identifier relating to the second terminal device. (Appendix 47) 47. The method of claim 46, further comprising the step of the network device using or storing a correspondence between the first identifier and the second identifier. (Appendix 48) 48. A method according to any one of Supplementary Notes 44 to 47, wherein the second identification information sent by the network device to the first terminal device is carried in a first RRC reconfiguration message, and the second identification information sent by the network device to the second terminal device is carried in a second RRC reconfiguration message. (Appendix 49) 46. ​​The method of claim 44 or 45, further comprising the step of: after the first terminal device and the second terminal device establish a connection, the network device receiving first identification information sent by the second terminal device, the first identification information indicating a first identifier for the second terminal device. (Appendix 50) 49. The method of claim 49, wherein the first identification information is carried by a measurement report message. (Appendix 51) 51. The method of claim 50, wherein the first RRC reconfiguration message indicates a first identifier that corresponds to the second identifier. (Appendix 52) 47. The method of claim 46, wherein the first identification information and the corresponding second identification information are carried by an SUI. (Appendix 53) 53. The method of claim 52, wherein the first identity and the corresponding second identity are newly added information elements in the SUI, or are included in a sidelink failure information element, or are included in a sidelink transmission resource request information element. (Appendix 54) An information transmission and reception method applied to a second terminal device, the second terminal device transmitting first identification information to a network device, the first identification information indicating a first identifier for the second terminal device; and / or A method comprising: a step of the second terminal device receiving second identification information transmitted by a network device, the second identification information indicating a second identifier of the second terminal device. (Appendix 55) 55. The method of claim 54, further comprising the step of the second terminal device transmitting the second identification information to the first terminal device. (Appendix 56) 56. The method of claim 55, wherein the second identification information is carried by a sidelink signaling message or a sidelink RRC message between the first terminal device and the second terminal device, the sidelink signaling message or the sidelink RRC message indicating the first identifier. (Appendix 57) The method of claim 54, wherein the second terminal device receives the second identification information sent by the network device via a second RRC reconfiguration message. (Appendix 58) The method of claim 54, wherein the second terminal device transmits the first identification information to the network device via a measurement report message. (Appendix 59) An information receiving method applied to a first terminal device, comprising: A method comprising: a step in which the first terminal device receives second identification information transmitted by a network device, the second identification information indicating a second identifier of the second terminal device, and the second terminal device decides to switch to be connected to the network device via the first terminal device. (Appendix 60) 60. The method of claim 59, further comprising a step of the first terminal device receiving the second identification information transmitted by the second terminal device. (Appendix 61) 61. The method of claim 60, wherein the second identification information transmitted by the second terminal device is carried in a sidelink signaling message or a sidelink RRC message between the first terminal device and the second terminal device, the sidelink signaling message or the sidelink RRC message indicating the first identifier. (Appendix 62) 59. The method of claim 59, wherein the second identification information sent by the second terminal device is carried via a first RRC reconfiguration message. (Appendix 63) 63. The method of claim 62, wherein the first RRC reconfiguration message indicates a first identification corresponding to the second identifier. (Appendix 64) 64. The method of claim 61 or 63, further comprising a step in which the first terminal device uses or stores a correspondence between the first identifier and the second identifier. (Appendix 65) 62. The method of claim 61, further comprising the step of the first terminal device sending first identification information and corresponding second identification information to the network device. (Appendix 66) 66. The method of claim 65, wherein the first identification information and the corresponding second identification information are carried by an SUI. (Appendix 67) 67. The method of claim 66, wherein the first identity and the corresponding second identity are newly added information elements in the SUI, or are included in a sidelink failure information element, or are included in a sidelink transmission resource request information element. (Appendix 68) 54. A network device comprising: a memory having a computer program stored therein; and a processor, the processor configured to execute the computer program to implement a method according to any one of claims 17 to 31 and 44 to 53. (Appendix 69) 10. A terminal device comprising: a memory having a computer program stored therein; and a processor, the processor configured to execute the computer program to implement a method according to any one of claims 1 to 16, 32 to 43, and 54 to 67. (Appendix 70) A communication system including a network device, a first terminal device, and a second terminal device, 54. A communications system, wherein the network device is configured to perform a method as described in any of Supplements 17 to 31 and 44 to 53, the first terminal device is configured to perform a method as described in any of Supplements 1 to 16 and 59 to 67, and the second terminal device is configured to perform a method as described in any of Supplements 32 to 43 and 54 to 58.

Claims

1. An information transmission device applied to a network device, a processing unit that determines to switch the second terminal device to connect to the network device via the first terminal device; a transmitting unit that transmits second identification information to the first terminal device after the processing unit determines to switch the second terminal device to connect to the network device via the first terminal device, the second identification information indicating a second identifier of the second terminal device; The second identification information transmitted to the first terminal device by the transmitter is carried by a first RRC reconfiguration message, and the first RRC reconfiguration message further includes first identification information indicating a first identifier corresponding to the second identifier; the second identifier is an 8-bit local / temporary identifier of the second terminal device; The transmitting unit transmits the second identification information to the second terminal device.

2. 2. The apparatus of claim 1, further comprising: a receiver configured to receive first identification information transmitted by the first terminal device, the first identification information indicating a first identifier for the second terminal device.

3. The apparatus according to claim 1 , wherein the second identification information transmitted by the transmitter to the second terminal apparatus is carried in a second RRC reconfiguration message.

4. 2. The device of claim 1, further comprising: a receiver that receives first identification information transmitted by the second terminal device, the first identification information indicating a first identifier for the second terminal device.

5. The apparatus of claim 2 , wherein the first identification information is carried by an SUI or by a second RRC message for the first terminal device.

6. The apparatus of claim 5 , wherein the first identification information is a newly added information element in the SUI or the second RRC message.

7. The device of claim 2 , wherein the first identifier is an L2 ID of the second terminal device.

8. The apparatus of claim 3 , wherein the second RRC reconfiguration message is a switch command containing relevant information about switching to the first terminal device.

9. The apparatus of claim 1 , wherein the first terminal device is a Relay UE and the second terminal device is a Remote UE.

10. a receiver configured to receive a measurement report transmitted by the second terminal device, the measurement report including an identifier of at least one candidate first terminal device, a serving cell identifier of the first terminal device, and a sidelink measurement result; The device according to claim 1 , wherein the processing unit, after receiving the measurement report, determines to switch the second terminal device to connect to the network device via the first terminal device.

11. 2. The apparatus of claim 1, further comprising: a receiving unit that receives an RRC reconfiguration complete message transmitted by the second terminal device via the first terminal device to complete switching the second terminal device to connect to the network device via the first terminal device.

12. An information transmitting and receiving device applied to a second terminal device, a transmitter configured to transmit first identification information to a network device, the first identification information indicating a first identifier related to the second terminal device; a receiver configured to receive second identification information transmitted by a network device, the second identification information indicating a second identifier of the second terminal device.

13. The apparatus of claim 12 , wherein the receiver receives the second identification information sent by the network device via a second RRC reconfiguration message.

14. 13. The apparatus of claim 12, further comprising: a processing unit that sends an RRC reconfiguration complete message to the network device via the first terminal device to complete switching to connect to the network device via the first terminal device.

15. 15. The apparatus of claim 14, wherein the transmitter transmits a measurement report, the measurement report including an identifier of at least one candidate first terminal device, a serving cell identifier of the first terminal device, and sidelink measurement results, and the measurement report is used by the network device to decide to switch the second terminal device to connect to the network device via the first terminal device.

16. An information receiving device applied to a first terminal device, a receiving unit that receives second identification information transmitted by a network device, the second identification information indicating a second identifier of a second terminal device, and the network device determines to switch the second terminal device to connect to the network device via the first terminal device; The second identification information received from the network device by the receiving unit is carried by a first RRC reconfiguration message, and the first RRC reconfiguration message further includes first identification information indicating a first identifier corresponding to the second identifier; The second identifier is an 8-bit local / temporary identifier of the second terminal device.

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