Method, device and communication system for transmitting and receiving information

Abstract

In an embodiment of the present invention, an apparatus for transmitting and receiving signals is provided, which is applicable to a terminal device, and the apparatus includes a first transceiver unit, which is configured to receive information of a candidate second terminal device for a first terminal device transmission; transmit a radio resource control reconfiguration message to the first terminal device, the radio resource control reconfiguration message including information of a target second terminal device in a radio resource control connection mode; and communicate with the first terminal device by the target second terminal device.

Description

[Technical field]

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

[0002] In 5G Release 17 (R17), sidelink relay (SL relay) technology is being researched, which includes a scenario of relaying from a terminal device (e.g., UE (also called terminal equipment)) to a network device (UE-to-Network Relay). Among them, the Uu interface of the relay terminal device (relay UE) uses a new air interface (NR) Uu link, and the PC5 interface between the remote terminal device (remote UE) and the relay UE is assumed to use an NR sidelink link. In the UE-to-Network Relay scenario, the relay UE is also called a UE-to-Network relay UE.

[0003] FIG. 1 illustrates a relay scenario from a terminal device to a network device.

[0004] As shown in Scenario 1 of FIG. 1, a remote UE 101 is out of coverage (OOC) of the network device 100, and a relay UE 102 is in coverage (IC) of the network device 100.

[0005] As shown in scenario 2 of FIG. 1, a remote UE 101 is in coverage (IC) of the network device 100, and a relay UE 102 is in coverage (IC) of the network device 100.

[0006] As shown in scenario 3 of FIG. 1, remote UE 101 is in coverage (IC) of network device 100a, relay UE 102 is in coverage (IC) of network device 100, and network device 100a is different from network device 100.

[0007] In the R17 L2 SL relay protocol stack, the Sidelink Relay Adaptation Protocol (SRAP) is introduced. In the case of UE-to-Network relay, for the PC5 and Uu interfaces, for the control plane and user plane protocol stacks, the SRAP sublayers are all above the Radio Link Control (RLC) sublayer. The Uu Service Data Adaptation Protocol (SDAP), Packet Data Convergence Protocol (PDCP) and Radio Resource Control (RRC) are terminated between the remote UE and the network device (e.g., gNB), while the SRAP, RLC, Medium Access Control (MAC) and Physical (PHY) layers are terminated at each link (i.e., the link between the remote UE and the relay UE and the link between the relay UE and the gNB).

[0008] FIG. 2 is a diagram showing the control plane protocol stack of the UE-to-Network relay.

[0009] In case of UE-to-Network relay, the SRAP sublayer on the PC5 interface is used only for bearer mapping purposes. For relaying messages on the Broadcast Control Channel (BCCH) and Paging Control Channel (PCCH) of the remote UE, the SRAP sublayer does not appear in the PC5 hop. For messages on the Signaling Radio Bearer 0 (SRB0) of the remote UE, the SRAP sublayer does not appear in the PC5 hop, but the SRAP sublayer appears in the Uu hop for downlink (DL) and uplink (UL).

[0010] It should be noted that the introduction of the above background art is intended to clearly and completely explain the technical solutions of the present invention, and to facilitate understanding thereof by those skilled in the art, and these technical solutions are described in the background art of the present invention, and therefore should not be construed as being known to those skilled in the art. Summary of the Invention [Problem to be solved by the invention]

[0011] A terminal device (e.g., UE) can directly communicate with a network device (e.g., Network or gNB), and the communication path can be referred to as a direct path. A terminal device can also communicate with a network device via a relay UE, and the communication path can be referred to as an indirect path. For the continuity of traffic of L2 UE-to-Network relay, when the UE switches from a direct path to an indirect path (i.e., direct to indirect path switch), the flow shown in FIG. 3 can be used.

[0012] As shown in FIG. 3, the process of a UE switching from a direct path to an indirect path includes the following steps:

[0013] Step 0: Uplink data and / or downlink data (UL / DL data) are transmitted between a remote UE and a network device (e.g., a gNB) via a Uu interface.

[0014] Step 1: After a remote UE measures and / or discovers candidate relay UEs, it reports one or more candidate relay UEs and conventional Uu measurement results.

[0015] Wherein, the remote UE may report at least a relay UE ID, a serving cell ID of the relay UE and SL measurement information, where the SL measurement information may be the sidelink reference signal received power (SL-RSRP) of the candidate relay UE, and if the SL-RSRP cannot be obtained, the sidelink discovery reference signal received power (SD-RSRP) is used.

[0016] Step 2a: The gNB decides to switch the remote UE to the target relay UE.

[0017] Step 2b: The gNB sends a radio resource control reconfiguration (RRCReconfiguration) message to the target relay UE, which may include at least the local / temp ID and layer 2 ID (L2 ID) of the remote UE, RLC configuration in which the Uu and PC5 interfaces are used for relaying, and bearer mapping configuration.

[0018] Step 3: The gNB sends an RRCReconfiguration message to the remote UE. The content of the message may include at least a Relay UE ID, a PC5 RLC configuration of the relay traffic, and a related end-to-end radio bearer. After receiving the RRCReconfiguration message from the gNB, the remote UE stops transmitting user plane (UP) and control plane (CP).

[0019] Step 4: The remote UE establishes a PC5 connection with the target relay UE.

[0020] Step 5: The remote UE sends a radio resource control reconfiguration complete (RRCReconfigurationComplete) message to the gNB via the relay UE to complete the path switch process.

[0021] Step 6: Between the Remote UE and the gNB, the data path is switched from a direct path to an indirect path.

[0022] In the path switching process shown in FIG. 3, the relay UE may be in a radio resource control idle (RRC_idle) mode, a radio resource control inactive (RRC_inactive) mode, or a radio resource control connected (RRC_connected) mode.

[0023] Among them, there are the following options for processing when the relay UE is in radio resource control idle (RRC_idle) mode or radio resource control inactive (RRC_inactive) mode.

[0024] Option 1: The target relay UE for the direct-to-indirect path switch must be in RRC_connected mode.

[0025] Option 2: A relay UE in RRC_idle or RRC_inactive mode may be designated as a target relay, and such a case is supported by a remote UE-initiated scheme, i.e., after receiving a path switch command (e.g., RRCReconfiguration), the remote UE establishes a PC5 link with the relay UE, and sends a switch completion (e.g., RRCReconfigurationComplete) message by the relay UE, which triggers the relay UE to enter RRC_connected mode.

[0026] The inventor of the present invention has found that: the above Option 1 and Option 2 each have problems to be solved. For example, in the case of Option 1, how to ensure that the target relay UE needs to be in connected mode is a problem to be solved; in the case of Option 2, when the target relay UE is in RRC_idle or RRC_inactive mode, the RRC reconfiguration message cannot be sent to the relay UE in step 2b of Fig. 3, so the direct-to-indirect path switch process shown in Fig. 3 cannot be performed smoothly.

[0027] In view of at least one of the above problems, an embodiment of the present invention provides a method, an apparatus and a communication system for transmitting and receiving information, in which a network device sends a radio resource control reconfiguration (RRC reconfiguration) message to a remote UE, the radio resource control reconfiguration (RRC reconfiguration) message includes information of a target relay UE in a radio resource control connected (RRC_connected) mode, so as to make the target relay UE in the RRC_connected mode, which is advantageous in adopting an existing direct-to-indirect path switch flow to switch the communication path between the remote UE and the network device, which can reduce the traffic interruption time of the remote UE, and which has a simple implementation method and low implementation complexity. [Means for solving the problem]

[0028] According to one aspect of an embodiment of the present invention, an apparatus for transmitting and receiving information is provided, which is applied to a network device, and the apparatus includes a first transceiver unit, and the first transceiver unit is configured as follows: Receive information of a candidate second terminal device (relay UE) for transmission from the first terminal device; Send a radio resource control reconfiguration (RRC reconfiguration) message to the first terminal device, where the radio resource control reconfiguration (RRC reconfiguration) message includes information of a target second terminal device (relay UE) in a radio resource control connected (RRC_connected) mode; and communicating with the first terminal device by the target second terminal device.

[0029] According to another aspect of an embodiment of the present invention, an apparatus for transmitting and receiving information is provided, which is applied to a first terminal device (remote UE), and the apparatus includes a second transceiver unit, the second transceiver unit being configured as follows: Sending information of a candidate second terminal device (relay UE) to a network device; Receive a radio resource control reconfiguration (RRC reconfiguration) message sent by the network device, the radio resource control reconfiguration (RRC reconfiguration) message including information of a target second terminal device (relay UE) in a radio resource control connected (RRC_connected) mode; and communicating with the network device by the target second terminal device. Effect of the Invention

[0030] The advantageous effects of the embodiment of the present invention at least include: a network device sends a radio resource control reconfiguration message to a remote UE, and the radio resource control reconfiguration message includes information of a target relay UE in a radio resource control connected mode, so that the target relay UE can be made to be in an RRC_connected mode; it is advantageous to adopt an existing direct-to-indirect path switch flow to switch the communication path between the remote UE and the network device, which can reduce the traffic interruption time of the remote UE; and the implementation method is simple and the implementation complexity is low.

[0031] With reference to the following description and drawings, specific embodiments of the present invention are disclosed in detail and show the manner in which the principles of the present invention may be employed. However, the scope of the present invention is not limited thereto. Within the scope of the appended claims, the embodiments of the present invention may include various changes, modifications, and alternatives.

[0032] Additionally, features described and / or illustrated in one embodiment may be used in the same or similar manner in one or more other embodiments, may be combined with features in the other embodiments, or may be substituted for features in the other embodiments.

[0033] It should be noted that terms such as "comprise / have" when used in this specification refer to the presence of a feature, element, step, or assembly, but do not exclude the presence or addition of one or more other features, elements, steps, or assemblies. [Brief description of the drawings]

[0034] Elements and features described in one drawing or one embodiment of the invention may be combined with elements and features shown in one or more other drawings or embodiments, and in the drawings, like reference numerals are used to indicate corresponding parts in the several drawings and to indicate corresponding parts used in several embodiments. [Figure 1] FIG. 1 illustrates a scenario of relay from a terminal device to a network device. [Diagram 2] A diagram showing the control plane protocol stack for UE-to-Network relay. [Diagram 3] A diagram showing the process by which a UE is switched from a direct path to an indirect path. [Figure 4] FIG. 2 illustrates a method for transmitting and receiving information in an embodiment of the first aspect. [Diagram 5] FIG. 11 illustrates a method for transmitting and receiving information in an embodiment of the second aspect. [Figure 6] A diagram showing switching from a direct path to an indirect path when a relay UE is in RRC_idle or RRC_inactive mode. [Figure 7] FIG. 13 illustrates an apparatus for transmitting and receiving information in an embodiment of the third aspect. [Figure 8] FIG. 13 illustrates an apparatus for transmitting and receiving information in an embodiment of the fourth aspect. [Figure 9] FIG. 13 illustrates an apparatus for transmitting and receiving information in an embodiment of the fifth aspect. [Figure 10] FIG. 13 illustrates an apparatus for transmitting and receiving information in an embodiment of the sixth aspect. [Figure 11] FIG. 13 illustrates an apparatus for transmitting and receiving information in an embodiment of the seventh aspect. [Figure 12] FIG. 13 is a diagram illustrating a terminal device in a communication system according to an embodiment of the eighth aspect. [Figure 13] FIG. 13 is a diagram illustrating a network device in a communication system according to an embodiment of the eighth aspect. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] The above and other features of the present invention will become apparent from the following detailed description and drawings, in which: Although the specification and drawings disclose specific embodiments of the present invention, they are merely illustrative of some of the embodiments that may employ the principles of the present invention, and it is to be understood that the present invention is not limited to the described embodiments, and that the present invention also includes all modifications, variations, and alternatives within the scope of the appended claims.

[0036] In embodiments of the present invention, the term "communications network" or "wireless communication network" may refer to a network conforming to any communication standard, such as New Radio (NR), Long Term Evolution (LTE), LTE-Advanced (LTE-A), Wideband Code Division Multiple Access (WCDMA), High-Speed ​​Packet Access (HSPA), etc.

[0037] Additionally, communications between devices in a communications system may occur according to any stage of communications protocol, including, but not limited to, the following communications protocols: 1G (generation), 2G, 2.5G, 2.75G, 3G, 4G, 4.5G, 5G, New Radio (NR), and / or other conventional or future developed communications protocols.

[0038] In the embodiment of the present invention, the term "network device" refers to a device that connects a terminal device to a communication network and provides services to the terminal device in a communication system, for example. The network device may include, but is not limited to, an IAB-node, a base station (BS), an access point (AP), a transmission reception point (TRP), a broadcast transmitter, a mobile management entity (MME), a network gateway, a server, a radio network controller (RNC), a base station controller (BSC), etc.

[0039] 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), and may further include 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 the functions thereof, and each base station may provide communication coverage for a particular geographical area. The term "cell" may refer to a base station and / or the area it covers, depending on the context of the term.

[0040] 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 services from the network, for example, via a network device. The User Equipment may be fixed or mobile, and may also be called a Mobile Station (MS), a terminal, a Subscriber Station (SS), an Access Terminal (AT), a station, etc.

[0041] Among these, user devices may include, but are not limited to, the following: cellular phones, personal digital assistants (PDAs), wireless modems, wireless communication devices, mobile devices, machine type communication devices, laptop computers, cordless telephones, smartphones, smart watches, digital cameras, etc.

[0042] Furthermore, in scenarios such as the Internet of Things (IoT), the user equipment may also be a monitoring or measuring device or equipment, 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.

[0043] Additionally, the term "network side" or "network device side" refers to the side of a network, which may be a base station or may include one or more network devices as described above. The term "user side" or "terminal side" or "terminal device side" refers to the side of a user or terminal, which may be a UE or may include one or more terminal devices as described above.

[0044] Unless confusion is caused, the term “uplink control signal” is interchangeable with “uplink control information (UCI)” or “Physical Uplink Control Channel (PUCCH)”, the term “uplink data signal” is interchangeable with “uplink data information” or “Physical Uplink Shared Channel (PUSCH)”, the term “downlink control signal” is interchangeable with “Downlink Control Information (DCI)” or “Physical Downlink Control Channel (PDCCH)”, and the term “downlink data signal” is interchangeable with “downlink data information” or “Physical Downlink Shared Channel (PDSCH)”.

[0045] Also, the transmission or reception of the PUSCH may be understood as transmitting or receiving uplink data carried by the PUSCH, the transmission or reception of the PUCCH may be understood as transmitting or receiving uplink information carried by the PUCCH, the transmission or reception of the PRACH may be understood as transmitting or receiving a preamble carried by the PRACH, and the uplink signal may include an uplink data signal and / or an uplink control signal, and may be called an uplink transmission (UL transmission), uplink information, or uplink channel. The transmission of an uplink transmission on an uplink resource may be understood as transmitting the uplink transmission using the uplink resource. Correspondingly, downlink data / signal / channel / information may also be understood in the same way.

[0046] In the embodiment of the present invention, the higher layer signaling may be, for example, Radio Resource Control (RRC) signaling, for example, referred to as an RRC message, including, for example, MIB, system information, dedicated RRC message, or referred to as an RRC information element (RRC IE). The higher layer signaling may be, for example, Medium Access Control (MAC) signaling, or referred to as an MAC control element (MAC CE). However, the present invention is not limited thereto.

[0047] In an embodiment of the present invention, the first terminal device may be the remote UE 101 shown in FIG. 1, the target second terminal device may be the relay UE 102 shown in FIG. 1, and the network device may be the network device 100 shown in FIG.

[0048] The target second terminal device may be one of a plurality of candidate second terminal devices, and the candidate second terminal device may be one or more of the second terminal devices. The target second terminal device may be called a target relay UE, and the candidate second terminal device may be called a candidate relay UE.

[0049] The first terminal device can directly communicate with the network device, i.e., the communication path is a direct path. The first terminal device can also communicate with the network device via the second terminal device, i.e., the communication path is an indirect path. The communication path between the first terminal device and the network device can be switched from the direct path to the indirect path (i.e., a direct-to-indirect path switch).

[0050] <Example of the first aspect> An embodiment of the first aspect of the present invention is intended to solve the problem in Option 1 above, namely, how to ensure that the target relay UE is in connected mode during the process of direct-to-indirect path switch.

[0051] 4 is a diagram illustrating a method for transmitting and receiving information in an embodiment of the first aspect. As shown in FIG. 4, the method for transmitting and receiving information includes the following operations (steps).

[0052] Operation 401: a first terminal device sends information of a candidate second terminal device to a network device; Operation 402: A first terminal device receives a radio resource control reconfiguration (RRC reconfiguration) message sent by a network device, the radio resource control reconfiguration (RRC reconfiguration) message including information of a target second terminal device (relay UE) in a radio resource control connected (RRC_connected) mode; and Operation 403: A first end device communicates with the network device via the target second end device.

[0053] According to an embodiment of the first aspect of the present invention, a network device sends a radio resource control reconfiguration message to a remote UE, and the radio resource control reconfiguration message includes information of a target relay UE in a radio resource control connected mode, so that the target relay UE can be made to be in an RRC_connected mode, which is advantageous in adopting an existing direct-to-indirect path switch flow (e.g., the flow shown in FIG. 3) to switch the communication path between the remote UE and the network device, which can reduce the traffic interruption time of the remote UE, and the implementation manner of the method is simple and the implementation complexity is low.

[0054] The implementation of the method shown in FIG. 4 will now be described in detail.

[0055] (Implementation method A1) In the implementation method A1, the target second terminal device (e.g., target relay UE) in the RRC reconfiguration message sent by the network device (e.g., gNB) to the first terminal device (e.g., remote UE) is a relay UE in RRC_connected mode. That is, the network device can select a relay UE in RRC_connected mode as a target relay UE from among the candidate second terminal devices (e.g., candidate relay UEs) reported by the remote UE.

[0056] For example, in one embodiment, a relay UE reports its L2 ID to a gNB after entering RRC_connected mode, or a relay UE reports its changed L2 ID to a gNB report when its L2 ID changes, where the L2 ID may be an identifier (ID) assigned by an upper layer (e.g., a V2X layer, a ProSe layer, or a NAS layer) in the relay UE, e.g., 24 bits, the L2 ID may be an L2 ID for traffic relay of the relay UE, and the relay UE may further report its relay capability (e.g., capability related to L2 UE-to-network relay) to the gNB, etc. In this way, the gNB can obtain what L2 ID of a relay UE is in RRC_connected mode, and when the gNB receives the L2 ID of a candidate relay UE in the measurement report of a remote UE, the gNB can determine the L2 ID of the candidate relay UE based on the L2 ID of the relay UE reported to the gNB by the relay UE after entering RRC_connected mode. Among the UEs, a relay UE in RRC_connected mode is selected as a target relay UE for route switching of the remote UE.

[0057] Also, for example, in another embodiment, the gNB allocates a Cell Radio Network Temporary Identifier (C-RNTI) for the relay UE, so that the gNB knows the C-RNTI of the relay UE in RRC_connected mode, and the remote UE can also report the C-RNTI of the candidate relay UE in the measurement report, so that the gNB can select the relay UE in RRC_connected mode as the target relay UE for the path switch of the remote UE based on the C-RNTI. In this embodiment, the relay UE needs to inform the remote UE of its C-RNTI, which can be sent, for example, by a PC5-S message or a PC5-RRC message or a sidelink medium access control element (Sidelink MAC CE) or sidelink control information (SCI), etc. Among them, the PC5-S message may be a discovery solicitation message, a discovery response message, a direct communication request message, a direct communication accept message, etc., and the PC5-RRC message may be a sidelink notification message (NotificationMessageSidelink) or a sidelink transfer Uu message (UuMessageTransferSidelink), etc.

[0058] (Implementation method A2) In implementation mode A2, a remote UE can report candidate relay UEs in RRC_connected mode to a network device, where the relay UE can indicate the RRC mode of the relay UE to the remote UE, so that the remote UE can only report candidate relay UEs in RRC_connected mode to the network device, that is, the measurement report sent by the remote UE to the network device can only include candidate relay UEs in RRC_connected mode, and not include candidate relay UEs in RRC_idle mode or RRC_inactive mode.

[0059] In implementation method A2, the instruction sent by the relay UE to the remote UE may be 1 bit (e.g., in the 1 bit instruction, 1 indicates that the relay UE is in RRC_connected mode, and 0 indicates that the relay UE is in another mode), or the instruction sent by the relay UE to the remote UE may include the RRC mode of the relay UE (e.g., the RRC mode of the relay UE may be RRC_connected, RRC_idle, or RRC_inactive).

[0060] In the embodiment A2, the instruction sent by the relay UE to the remote UE may be sent by a PC5-S message, a PC5-RRC message, sidelink system information, or a sidelink medium access control element (Sidelink MAC CE), etc., where the PC5-S message may be a discovery solicitation message, a discovery response message, a direct communication request message, or a direct communication accept message, etc., the PC5-RRC message may be a sidelink notification message (NotificationMessageSidelink) or a sidelink transfer Uu message (UuMessageTransferSidelink), etc., the sidelink system information may be a sidelink master information block (SL-MIB, MasterInformationBlockSidelink), etc., and the sidelink MAC CE may be a MAC CE with a length of 1 byte, etc.

[0061] (Implementation method A3) In implementation method A3, the network device can indicate relay UEs in RRC_connected mode in the measurement configuration, so that the remote UE can measure the link quality only with the relay UEs in RRC_connected mode.

[0062] In at least one embodiment of the implementation mode A3, when the network device configures the measurement object, it may increase the relay UE information for the relay UE, and the increased relay UE information may be, for example, the L2 ID or C-RNTI of the relay UE, and these relay UEs are in RRC_connected mode. In this way, when the remote UE receives the relay measurement object configuration, it can only measure the relay UE indicated by the network device, that is, it can only measure the relay UE in RRC_connected mode, so that the candidate relay UE in the measurement report sent by the remote UE to the network device is the relay UE in RRC_connected mode.

[0063] (Implementation method A4) In implementation mode A4, a relay UE providing relay service remains in RRC_connected mode, and when the relay UE enters RRC_idle or RRC_inactive mode, it does not provide relay service.

[0064] In implementation A4, the network device may not instruct the relay UE to enter RRC_idle or RRC_inactive mode, for example, the network device does not send an RRC release message or an RRC release message with a suspend indication to a relay UE that is capable of being a relay UE or that is to be a relay UE, or the network device can accept the RRC connection establishment request, RRC re-establishment request, RRC resume request, etc. of the relay UE, i.e., the network device does not reject these requests of the relay UE, so that the relay UE can be maintained in RRC_connected mode;and / or when a relay UE is in RRC_idle or RRC_inactive mode, the relay UE does not send a message related to a discovery procedure to a remote UE, for example, the relay UE does not send at least one of the following messages on the sidelink: a discovery solicitation message, a discovery response message, a direct communication request message, a direct communication accept message, and sidelink system information (e.g., SL-MIB), thereby preventing a remote UE from discovering the relay UE; or the relay UE does not perform a function related to relaying, for example, the relay UE does not send a discovery solicitation message and / or a discovery response message and / or a direct communication request message and / or a direct communication accept message on the sidelink. Indicate in the Sidelink_Accept message and / or in the Sidelink system information (e.g., SL-MIB) that it does not perform functions related to relaying, does not have relaying capabilities, or does not provide connectivity from remote UE to the network, etc.;

[0065] The embodiment of the first aspect provides a method for causing the target relay UE to be in RRC_connected mode, which is advantageous in adopting the existing direct-to-indirect path switch flow to switch the communication path between the remote UE and the network, thereby reducing the traffic interruption time of the remote UE, and the signal transmission and reception method in the embodiment of the first aspect is simple and has low implementation complexity.

[0066] <Example of the second aspect> An embodiment of the second aspect of the present invention is intended to solve the problem in Option 2 mentioned above, i.e., how a target relay UE receives an RRC reconfiguration message when the target relay UE is in RRC_idle or RRC_inactive mode during a direct-to-indirect path switch.

[0067] 5 is a diagram illustrating another method for transmitting and receiving information in an embodiment of the second aspect. As shown in FIG. 5, the method for transmitting and receiving information includes the following operations.

[0068] Operation 501: A second terminal device (relay UE) in a radio resource control idle (RRC_idle) mode or a radio resource control inactive (RRC_inactive) mode receives a radio resource control reconfiguration complete (RRC reconfiguration complete) message sent by a first terminal device (remote UE) and enters a radio resource control connected (RRC_connected) mode; and Operation 502: The second terminal device receives a radio resource control reconfiguration (RRC reconfiguration) message sent by a network device, and performs relay-related configuration of a PC5 interface and a Uu interface.

[0069] In operation 502, the RRC reconfiguration message of the relay UE may be transmitted after the relay UE enters the RRC_connected mode, or may be transmitted after the relay UE enters the RRC_connected mode and transmits the L2 ID of the relay UE to a network device (e.g., a gNB).

[0070] In an embodiment of the second aspect, the relay UE may, for example, send its L2 ID to the gNB via a Sidelink User Equipment Information (SUI) message, for the purpose of allowing the gNB to identify that the relay UE that has entered RRC_connected mode is a target relay UE for a path switch of a remote UE, and then perform associated configuration of the PC5 interface and the Uu interface by sending an RRC reconfiguration message to the target relay UE.

[0071] Wherein, the condition for the relay UE to send the L2 ID (for example, send the L2 ID through an SUI message), or the condition for initiating the SUI procedure, or the purpose for initiating the SUI may include the following: the relay UE receives an RRC reconfiguration complete message sent by a remote UE, for example, the RRC reconfiguration complete message is sent by the remote UE to a network device via the relay UE, or is an RRC reconfiguration complete message carried in an SRB0 received by the relay UE from the remote UE over the PC5 interface, or the relay UE receives an RRC reconfiguration complete message sent by the relay UE over the PC5 interface using default configuration (or specified (predetermined) configuration or predefined configuration). Upon receiving a complete message, the default configuration (or predefined configuration or pre-defined configuration) may be a default (or predefined or pre-defined) sidelink RLC bearer configuration, for example a default (or predefined or pre-defined) SL-RLC0 configuration or a default SL-RLC1 configuration, and the default (or predefined or pre-defined) sidelink RLC bearer configuration may include at least one of the following: SN length, reconfiguration time, logical channel indicator, logical channel priority, prioritized bit rate, logical channel group configuration, etc.

[0072] 6 is a diagram illustrating switching from a direct path to an indirect path when a relay UE is in RRC_idle or RRC_inactive mode. As shown in FIG. 6, the path switching process includes the following operations:

[0073] Operation 0: Transmit uplink data and / or downlink data (UL / DL data) between a remote UE and a network device (e.g., a gNB) via a Uu interface.

[0074] Operation 1a: The gNB sends a measurement configuration to the remote UE.

[0075] Operation 1b: after the remote UE measures and / or discovers the candidate relay UEs, it reports the IDs of one or more candidate relay UEs, and the remote UE can also report conventional Uu measurement results.

[0076] Wherein, the remote UE may report at least a relay UE ID, a serving cell ID of the relay UE, and SL measurement information, where the SL measurement information may be a sidelink reference signal received power (SL-RSRP) of the candidate relay UE, and if the SL-RSRP cannot be obtained, the sidelink discovery reference signal received power (SD-RSRP) is used.

[0077] Operation 2: The gNB decides to switch the remote UE to the target relay UE.

[0078] Operation 3: The gNB sends an RRCReconfiguration message to the remote UE. The content of the message may include at least a Relay UE ID, a PC5 RLC configuration of the relay traffic, and a related end-to-end radio bearer. After receiving the RRCReconfiguration message from the gNB, the remote UE stops transmitting the user plane (UP) and control plane (CP).

[0079] Operation 4: The remote UE establishes a PC5 connection with the target relay UE.

[0080] Operation 5: The remote UE sends a radio resource control reconfiguration complete (RRCReconfigurationComplete) to the target relay UE.

[0081] Operation 6: The target relay UE sends a radio resource control establishment request message to the gNB. For example, when the target relay UE receives an RRC reconfiguration complete message of the remote UE, the target relay UE can trigger its own RRC connection establishment procedure.

[0082] Operation 7: The gNB sends a radio resource control establishment message to the target relay UE.

[0083] Operation 8: The target relay UE sends a radio resource control establishment completion message to the gNB.

[0084] Operation 9: The target relay UE indicates the UE identity (UE ID, for example, L2 ID or C-RNTI) of the target relay UE and the layer 2 identity (L2 ID) of the remote UE through an SUI message.

[0085] Operation 10: The gNB sends a radio resource control reconfiguration (RRC reconfiguration) message to the target relay UE, where the message includes at least the local ID and layer 2 ID (L2 ID) of the remote UE, RLC configuration in which the Uu and PC5 interfaces are used for relaying, and bearer mapping configuration.

[0086] Operation 11: The target relay UE sends a radio resource control reconfiguration complete message to the gNB.

[0087] Operation 12: The target relay UE forwards the RRC reconfiguration complete message sent by the remote UE received in operation 5 to the gNB, and completes the path switch process.

[0088] Operation 13: The data path between the remote UE and the gNB is switched from a direct path to an indirect path, i.e., the remote UE transmits uplink data and / or downlink data (UL and / or DL ​​data) to the gNB via the target relay UE.

[0089] In operation 3 of Figure 6, the remote UE has already received the RRC reconfiguration message sent by the network device and can perform related settings such as SRAP and RLC channel of the PC5 interface, so in operation 5, the remote UE can theoretically send an RRC reconfiguration complete message on SRB1, and the RRC reconfiguration complete message can be transmitted using the SRAP sublayer on the PC5 interface. However, the relay UE has not yet received the RRC reconfiguration message sent by the network device and performed related settings of the PC5 interface and the Uu interface (including SRAP setting and RLC channel setting of the PC5 interface), for example, the relay UE may not have established or configured an SRAP entity and / or an RLC channel on the PC5 interface, so when the remote UE sends the RRC reconfiguration complete message using the SRAP sublayer, the relay UE may not receive the RRC reconfiguration complete message correctly.

[0090] Therefore, in operation 5 of Figure 6, in order to ensure that the target relay UE accurately receives the RRC reconfiguration complete message sent by the remote UE, the remote UE's transmission of the RRC reconfiguration complete message may not use the related function of SRAP on the PC5 interface, or SRAP may not appear, or the remote UE's RRC reconfiguration complete message may be sent using SRB0, or the remote UE may send the RRC reconfiguration complete message using a default configuration, and the default configuration (or default configuration or predefined configuration) may be the above-mentioned default (or default or predefined) sidelink RLC bearer configuration, etc.

[0091] According to the method of transmitting and receiving information in the embodiment of the second aspect, when a relay UE originally in RRC_idle mode or RRC_inactive mode enters RRC_connected mode and becomes a target relay UE, the relay UE can accurately receive the RRC reconfiguration complete message sent by the remote UE via the PC5 interface, and can ensure that the remote UE successfully completes switching from a direct path to communicating with the network via the RRC_connected relay UE (indirect path).

[0092] <Example of the third aspect> In an embodiment of the third aspect, an apparatus for transmitting and receiving information is provided, which is applied in a network device, for example, the network device 100 in Fig. 1. The function of the apparatus for transmitting and receiving information corresponds to the method of the network device in the embodiment of the first aspect.

[0093] 7 is a diagram illustrating an apparatus for transmitting and receiving information according to an embodiment of the third aspect. As shown in FIG. 7, the apparatus for transmitting and receiving information 700 includes a first transceiver unit 701, and the first transceiver unit 701 is configured as follows.

[0094] A first terminal device (e.g., a remote UE) receives information of a candidate second terminal device (relay UE) for transmission; Send a radio resource control reconfiguration (RRC reconfiguration) message to the first terminal device, where the radio resource control reconfiguration (RRC reconfiguration) message includes information of a target second terminal device (e.g., a target relay UE) in a radio resource control connected (RRC_connected) mode; and The target second terminal device communicates with the first terminal device.

[0095] According to an embodiment of the third aspect, the target second terminal device can be in RRC_connected mode, which is advantageous in adopting the existing direct-to-indirect path switch flow to switch the communication path between the remote UE and the network, thereby reducing the traffic interruption time of the remote UE, and the implementation method is simple and the implementation complexity is low.

[0096] Corresponding to implementation method A1 of the embodiment of the first aspect, the first transceiver unit 701 can select a candidate second terminal device in radio resource control connected (RRC_connected) mode as a target second terminal device based on information of a candidate second terminal device (e.g., a candidate relay UE) for the first terminal device transmission.

[0097] In one embodiment, the first transceiver unit 701 receives indicator information of a second terminal device transmitting in a radio resource control connected (RRC_connected) mode, for example, the indicator information is a layer 2 indicator (L2 L2 ID). The first transceiver unit 701 can select a candidate second terminal device in a radio resource control connected (RRC_connected) mode according to the indicator information and the information of a candidate second terminal device (for example, a candidate relay UE) of the first terminal device transmitting.

[0098] For example, a candidate second terminal device (e.g., a candidate relay UE) reports its L2 ID to the gNB after entering the RRC_connected mode, or the candidate relay UE reports its changed L2 ID to the gNB when its L2 ID changes, and the L2 ID may be an indicator assigned by an upper layer (e.g., a V2X layer, a ProSe layer, or a NAS layer) in the candidate relay UE, for example, 24 bits, and the L2 ID may be an L2 ID for traffic relay of the candidate relay UE, and the candidate relay UE may further transmit its relay capability (e.g., capability related to L2 UE-to-Network relay) to the gNB (e.g., the first transceiver unit 701 of the gNB). In this way, the gNB can obtain what L2 ID of the relay UE is in the RRC_connected mode, and when the gNB receives the L2 ID of the candidate relay UE in the measurement report of the remote UE, the gNB can obtain the L2 ID of the relay UE reported to the gNB by the relay UE after entering the RRC_connected mode. According to the L2 ID of the UE, a relay UE in RRC_connected mode can be selected from the candidate relay UEs as a target relay UE for route switching of the remote UE.

[0099] In another embodiment, the network device can assign the indicator information of the second terminal device, for example, the indicator information can be a Cell Radio Network Temporary Identifier (C-RNTI). The first transceiver unit 701 can select a candidate second terminal device in a radio resource control connected (RRC_connected) mode according to the indicator information and the information of the candidate second terminal device (e.g., the candidate relay UE) of the first terminal device transmission.

[0100] When the identification information is a Cell Radio Network Temporary Identifier (C-RNTI), the second terminal device can transmit the identification information of the second terminal device to the first terminal device.

[0101] Corresponding to the implementation manner A2 of the embodiment of the first aspect, the first transceiver unit 701 can receive information of a candidate second terminal device (relay UE) in a radio resource control connected (RRC_connected) mode of the first terminal device transmission.

[0102] Corresponding to the implementation mode A3 of the embodiment of the first aspect, the first transceiver unit 701 may further be configured as follows: send indication information to the first terminal device to indicate a second terminal device in a connected mode, so that the first terminal device can measure the second terminal device in a connected mode according to the indication information, and the first transceiver unit 701 can receive information of a candidate second terminal device (relay UE) in a connected mode, which is sent by the first terminal device according to the measurement result.

[0103] Corresponding to the implementation mode A4 of the embodiment of the first aspect, for a target second terminal device in a radio resource control connected (RRC_connected) mode, the first transceiver unit 701 does not instruct the target second terminal device to enter a non-connected mode. For example, the first transceiver unit 701 does not send an RRC release message or an RRC release message with a suspend indication to a relay UE that has the capability of being a relay UE or is to be a relay UE, or the first transceiver unit 701 accepts the RRC connection establishment request, RRC re-establishment request, or RRC resume request of the relay UE, i.e., the first transceiver unit 701 does not reject these requests of the relay UE, so that the relay UE can be kept in an RRC_connected mode.

[0104] <Example of the fourth aspect> In an embodiment of the fourth aspect, an apparatus for transmitting and receiving information is provided, which is applied to a first terminal device, for example, the remote UE 101 in Fig. 1. The function of the apparatus for transmitting and receiving information corresponds to the method of the remote UE in the embodiment of the first aspect.

[0105] 8 is a diagram illustrating an apparatus for transmitting and receiving information in an embodiment of the fourth aspect. As shown in FIG. 8, the apparatus for transmitting and receiving information 800 includes a second transceiver unit 801, and the second transceiver unit 801 is configured as follows:

[0106] Sending information of a candidate second terminal device (e.g., a candidate relay UE) to a network device; Receive a radio resource control reconfiguration (RRC reconfiguration) message sent by the network device, the radio resource control reconfiguration (RRC reconfiguration) message including information of a target second terminal device (relay UE) in a radio resource control connected (RRC_connected) mode; and The target second terminal device communicates with a network device.

[0107] According to an embodiment of the fourth aspect, the target second terminal device can be in RRC_connected mode, which is advantageous in adopting the existing direct-to-indirect path switch flow to switch the communication path between the remote UE and the network, thereby reducing the traffic interruption time of the remote UE, and the implementation method is simple and the implementation complexity is low.

[0108] Corresponding to the implementation manner A2 of the embodiment of the first aspect, the second transceiver unit 801 sends information of a candidate second terminal device (eg, a candidate relay UE) in a radio resource control connected (RRC_connected) mode to a network device.

[0109] The second transceiver unit 801 further receives indication information for indicating the RRC mode of the second terminal device of the second terminal device transmission. Thus, the second transceiver unit 801 can transmit information of the candidate second terminal device (relay UE) in radio resource control connected (RRC_connected) mode to the network device according to the indication information. For example, the indication sent by the relay UE to the second transceiver unit 801 may be transmitted by a PC5-S message, a PC5-RRC message, sidelink system information, or a sidelink media access control element (Sidelink MAC CE), etc. Among them, the PC5-S message may be a discovery solicitation message, a discovery response message, a direct communication request message, or a direct communication accept message, etc., the PC5-RRC message may be a sidelink notification message (NotificationMessageSidelink) or a sidelink transfer Uu message (UuMessageTransferSidelink), etc., the sidelink system information may be a sidelink master information block (SL-MIB, MasterInformationBlockSidelink), etc., and the sidelink MAC CE may be a MAC CE with a length of 1 byte, etc.

[0110] Corresponding to the implementation mode A3 of the embodiment of the first aspect, the second transceiver unit 801 may further be configured as follows: receiving indication information from the network device for indicating the second terminal device in a connected mode; and Based on the indication information, the second terminal device in the connected mode is measured.

[0111] Thus, the second transceiver unit 801 can send information of candidate second terminal devices (eg, candidate relay UEs) in connected mode to the network device based on the result of the above-mentioned measurement.

[0112] <Example of the fifth aspect> In an embodiment of the fifth aspect, an information transmitting and receiving device is provided, which is applied to a second terminal device, for example, the relay UE 102 in FIG. 1. The function of the information transmitting and receiving device corresponds to the method of the relay UE of the implementation mode A4 in the embodiment of the first aspect.

[0113] 9 is a diagram illustrating an apparatus for transmitting and receiving information according to an embodiment of the fifth aspect. As shown in FIG. 9, the apparatus for transmitting and receiving information 900 includes a third transceiver unit 901, and the third transceiver unit 901 is configured as follows:

[0114] When the second terminal device is not in radio resource control connected (RRC_connected) mode (e.g., in RRC_idle or RRC_inactive mode), the third transceiver unit 901 does not send messages related to the discovery procedure or perform relay-related functions.

[0115] Among them, the third transceiver unit 901 not sending messages related to a discovery procedure includes, for example, the following, that is, the third transceiver unit 901 not sending at least one of the following messages on the sidelink, namely, a discovery solicitation message, a discovery response message, a direct communication request message, a direct communication accept message, and sidelink system information (e.g., SL-MIB), thereby preventing a remote UE from discovering the relay UE. The third transceiver unit 901 not performing relay-related functions includes, for example, the following: the third transceiver unit 901 indicates in a discovery solicitation message and / or a discovery response message and / or a direct communication request message and / or a direct communication accept message and / or sidelink system information (e.g., SL-MIB) transmitted on the sidelink that it does not perform relay-related functions, does not have relay capability, or does not provide a connection from a remote UE to the network, etc.

[0116] This can prevent a relay UE that is not in a radio resource control connected (RRC_connected) mode from being discovered by a remote UE, or can prevent the relay UE from providing a relay service to the remote UE.

[0117] <Example of the sixth aspect> In an embodiment of the sixth aspect, an apparatus for transmitting and receiving information is provided, which is applied in a network device, for example, the network device 100 in Fig. 1. The function of the apparatus for transmitting and receiving information corresponds to the method of the network device in the embodiment of the second aspect.

[0118] 10 is a diagram illustrating an information transmitting / receiving device according to an embodiment of the sixth aspect. As shown in FIG. 10, the information transmitting / receiving device 1000 includes a fourth transceiver unit 1001, and the fourth transceiver unit 1001 is configured as follows:

[0119] When the second terminal device enters the radio resource control connected (RRC_connected) mode, the fourth transceiver unit 1001 sends a radio resource control reconfiguration (RRC reconfiguration) message to the second terminal device, causing the second terminal device to perform relay-related settings of the PC5 interface and the Uu interface.

[0120] In at least one embodiment, the fourth transceiver unit 1001 is further configured to receive the identification information of the second terminal device transmitted. For example, the fourth transceiver unit 1001 receives the identification information from the second terminal device through a Sidelink UE Information (SUI) message. The identification information may be, for example, the L2 ID of the second terminal device.

[0121] In at least one embodiment, the fourth transceiver unit 101 receives the indication information from the second terminal device via a Sidelink User Equipment Information (SUI) message (e.g., operation 9 in FIG. 6 ) before sending a Radio Resource Control reconfiguration (RRC reconfiguration) message (e.g., operation 10 in FIG. 6 ).

[0122] According to an embodiment of the sixth aspect, when a relay UE originally in RRC_idle mode or RRC_inactive mode enters RRC_connected mode and becomes a target relay UE, it can accurately receive the RRC reconfiguration complete message sent by the remote UE on the PC5 interface, and can ensure that the remote UE successfully completes switching from a direct path to network communication via the RRC_connected relay UE (indirect path).

[0123] <Example of the seventh aspect> In an embodiment of the seventh aspect, an apparatus for transmitting and receiving information is provided, which is applied to a second terminal device, for example, the relay UE 102 in Fig. 1. The function of the apparatus for transmitting and receiving information corresponds to the method of the second terminal device (for example, the relay UE) in the embodiment of the second aspect.

[0124] 11 is a diagram illustrating an information transmitting / receiving device according to an embodiment of the seventh aspect. As shown in FIG. 11, the information transmitting / receiving device 1100 includes a fifth transceiver unit 1101, and the fifth transceiver unit 1101 is configured as follows:

[0125] When the second terminal device is in a radio resource control idle (RRC_idle) mode or a radio resource control inactive (RRC_inactive) mode, the fifth transceiver unit 1101 receives a radio resource control reconfiguration complete (RRC reconfiguration complete) message sent by a first terminal device (remote UE), and causes the second terminal device to enter a radio resource control connected (RRC_connected) mode; and Receive a radio resource control reconfiguration (RRC reconfiguration) message sent by the network device, and cause the second terminal device to perform relay-related configuration of the PC5 interface and the Uu interface.

[0126] In at least one embodiment, the fifth transceiver unit 1101 may be further configured to send identification information to the network device, the identification information being, for example, the L2 ID of the second terminal device.

[0127] Wherein, the fifth transceiver unit 1101 can send the indication information to the network device through a Sidelink UE Information (SUI) message.

[0128] The condition for the fifth transceiver unit 1101 to transmit the indicator information or the condition for initiating the SUI procedure or the purpose for initiating the SUI may include the following: the second terminal device receives a radio resource control reconfiguration complete (RRC reconfiguration complete) message transmitted by the first terminal device. For example, the RRC reconfiguration complete message is transmitted by the first terminal device (e.g., a remote UE) to a network device via the second terminal device (e.g., a relay UE), or is the radio resource control reconfiguration complete (RRC reconfiguration complete) message carried by an SRB0 received by the fifth transceiver unit 1101 from the first terminal device over the PC5 interface, or is the radio resource control reconfiguration complete (RRC reconfiguration complete) message transmitted by the fifth transceiver unit 1101 over the PC5 interface from the first terminal device using default settings. complete) message, wherein the default configuration (or predefined configuration or predefined configuration) may be a default (or predefined or predefined) sidelink RLC bearer configuration, for example a default (or predefined or predefined) SL-RLC0 configuration or a default (or predefined or predefined) SL-RLC1 configuration, and the default (or predefined or predefined) sidelink RLC bearer configuration may include at least one of the following: SN length, reconfiguration time, logical channel indicator, logical channel priority, prioritized bit rate, logical channel set configuration, etc.

[0129] In at least one embodiment, after sending the indication information to the network device, the fifth transceiver unit 1101 receives a radio resource control reconfiguration (RRC reconfiguration) message from the network device.

[0130] According to an embodiment of the sixth aspect, when a relay UE originally in RRC_idle mode or RRC_inactive mode enters RRC_connected mode and becomes a target relay UE, the RRC reconfiguration complete message sent by the remote UE on the PC5 interface can be accurately received, and it can be ensured that the remote UE successfully completes switching from a direct path to communicating with the network via the RRC_connected relay UE (indirect path).

[0131] <Example of the eighth aspect> An embodiment of the present invention further provides a communication system, which may include a first terminal device, a second terminal device and a network device, for example, the first terminal device may be the remote UE 101 in Fig. 1, the second terminal device may be the relay UE 102 in Fig. 1, and the network device may be the network device 100 in Fig. 1. Wherein, the first terminal device and the second terminal device may adopt the same terminal device configuration.

[0132] Fig. 12 is a diagram showing a terminal device in a communication system according to an embodiment of the eighth aspect of the present invention. The terminal device shown in Fig. 12 may be used as the first terminal device or may be used as the second terminal device.

[0133] 12, the terminal device 1200 may include a processor 1210 (e.g., a central processing unit CPU) and a memory 1220, which is connected to the processor 1210. The memory 1220 can store various data, and can further store a program 1230 for processing memory information, and can execute the program 1230 under the control of the processor 1210.

[0134] For example, the processor 1210 may be configured to execute a program to implement a method according to an embodiment of the first or second aspect.

[0135] 12, the terminal device 1200 may further include a transceiver 1240, an antenna 1250, etc., and the functions of these components are similar to those of the conventional technology, so detailed description thereof will be omitted here. Note that the terminal device 1200 does not need to include all the components shown in Fig. 12. The terminal device 1200 may further include components not shown in Fig. 12, but the conventional technology can be referred to for this.

[0136] FIG. 13 is a diagram illustrating a network device in a communication system according to an embodiment of the eighth aspect.

[0137] 13, the network device 1300 may include a processor 1310 (e.g., a central processing unit CPU) and a memory 1320, and the memory 1320 is connected to the processor 1310. The memory 1320 can store various data, and can further store a program 1330 for information processing, and can execute the program 1330 under the control of the processor 1310.

[0138] For example, the processor 1310 may be configured to execute a program to implement a method according to an embodiment of the first or second aspect.

[0139] 13, the network device 1300 may further include a transceiver 1340, an antenna 1350, etc., among which the functions of these components are the same as those of the prior art, and therefore detailed description thereof will be omitted here. Note that the network device 1300 does not need to include all the components shown in FIG. 13. The network device 1300 may further include components not shown in FIG. 13, and the prior art can be referred to for this.

[0140] In an embodiment of the present invention, a computer program is further provided, in which, when the program is executed on a first terminal device or a second terminal device, the program causes the first terminal device or the second terminal device to perform the method described in the embodiments of the first and second aspects.

[0141] In an embodiment of the present invention, a storage medium storing a computer program is further provided, in which the computer program causes the first terminal device or the second terminal device to execute the method described in the embodiments of the first and second aspects.

[0142] In an embodiment of the present invention, a computer program is further provided, which, when executed in a network device, causes the network device to perform the method described in the embodiments of the first and second aspects.

[0143] An embodiment of the present invention further provides a storage medium storing a computer program, wherein the computer program causes a network device to perform the method described in the embodiment of the first and second aspects.

[0144] The above-mentioned devices and methods may be realized by software or hardware, or may be realized by a combination of hardware and software. The present invention further relates to a computer-readable program, which, when executed by a logic component, causes the logic component to realize the above-mentioned devices or components, or causes the logic component to realize the above-mentioned methods or steps. The logic component may be, for example, a Field Programmable Gate Array (FPGA), a microprocessor, a processor for use in a computer, etc. The present invention also relates to a storage medium, such as a hard disk, a magnetic disk, an optical hard disk, a DVD, a flash memory, etc., storing the above-mentioned program.

[0145] Additionally, one or more combinations of the functional blocks illustrated in the figures and / or one or more combinations of the functional blocks may be implemented as 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 component, a discrete gate or transistor logic component, a discrete hardware assembly, or any other suitable combination for performing the functions described herein. Also, one or more combinations of the functional blocks illustrated in the figures and / or one or more combinations of the functional blocks may be further configured as 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 communication with a DSP, or any other configuration.

[0146] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to such embodiments, and any modifications to the present invention fall within the technical scope of the present invention as long as they do not depart from the spirit of the present invention.

[0147] Furthermore, with respect to the above-mentioned embodiments, the following supplementary notes are disclosed.

[0148] (Appendix 1) 1. A method for transmitting and receiving information, adapted for a network device, the method comprising: Receive information of a candidate second terminal device (relay UE) for transmission from the first terminal device; Send a radio resource control reconfiguration (RRC reconfiguration) message to the first terminal device, where the radio resource control reconfiguration (RRC reconfiguration) message includes information of a target second terminal device (relay UE) in a radio resource control connected (RRC_connected) mode; and the network device communicating with the first end device by the target second end device.

[0149] (Appendix 2) 2. The method according to claim 1, comprising: A method in which the network device selects a candidate second terminal device in radio resource control connected (RRC_connected) mode as the target second terminal device based on information of the candidate second terminal device (relay UE) transmitted by the first terminal device.

[0150] (Appendix 3) 3. The method according to claim 1 or 2, The network device receives an indication of a second terminal device sending an indication of a second terminal device that has entered a radio resource control connected (RRC_connected) mode; A method in which the network device selects a candidate second terminal device in a radio resource control connected (RRC_connected) mode based on the indication information and information of the candidate second terminal device (relay UE) transmitted by the first terminal device.

[0151] (Appendix 4) 4. The method according to claim 3, comprising: The method, wherein the labeling information is layer 2 (L2) labeling information.

[0152] (Appendix 5) 3. The method according to claim 1 or 2, the network device assigns identification information of the second terminal device; A method in which the network device selects a candidate second terminal device in a radio resource control connected (RRC_connected) mode based on the indication information and information of the candidate second terminal device (relay UE) transmitted by the first terminal device.

[0153] (Appendix 6) 6. The method according to claim 5, The method, wherein the indicator information is a Cell Radio Network Temporary Identifier (C-RNTI).

[0154] (Appendix 7) 7. The method according to claim 6, comprising: A method, wherein the first terminal device receives the indicator information transmitted by a second terminal device when the indicator information is a Cell Radio Network Temporary Identifier (C-RNTI).

[0155] (Appendix 8) 2. The method according to claim 1, comprising: A method in which the network device receives information of a candidate second terminal device (relay UE) in a radio resource control connected (RRC_connected) mode of the first terminal device transmission.

[0156] (Appendix 8A) 2. The method according to claim 1, comprising: The method further comprises: The network device transmits, to the first terminal device, indication information for indicating the second terminal device being in a connection mode; A method in which the first terminal device measures a second terminal device in a connected mode based on the indication information, and the network device receives information of a candidate second terminal device (relay UE) that the first terminal device transmits based on the result of the measurement.

[0157] (Appendix 9) 2. The method according to claim 1, comprising: A method, wherein for a target second terminal device in a radio resource control connected (RRC_connected) mode, the network device does not instruct the target second terminal device to enter a non-connected mode.

[0158] (Appendix 10) 1. A method for transmitting and receiving information, adapted for a second terminal device, the method comprising: A method in which, when not in a radio resource control connected (RRC_connected) mode, the second terminal device does not send messages related to a discovery procedure or perform relay-related functions.

[0159] (Appendix 11) A method for transmitting and receiving information, the method being applied to a first terminal device (remote UE), the method comprising: Sending information of a candidate second terminal device (relay UE) to a network device; Receive a radio resource control reconfiguration (RRC reconfiguration) message sent by the network device, the radio resource control reconfiguration (RRC reconfiguration) message including information of a target second terminal device (relay UE) in a radio resource control connected (RRC_connected) mode; and the first end device communicating with the network device by the target second end device.

[0160] (Appendix 12) 12. The method according to claim 11, A method in which the first terminal device transmits information of a candidate second terminal device (relay UE) in a radio resource control connected (RRC_connected) mode to the network device.

[0161] (Appendix 13) 13. The method of claim 12, further comprising: The method further comprises: The first terminal device receives indication information transmitted by a second terminal device for indicating an RRC mode of the second terminal device; A method in which the first terminal device sends information of a candidate second terminal device (relay UE) in a radio resource control connected (RRC_connected) mode to the network device based on the indication information.

[0162] (Appendix 14) 12. The method according to claim 11, The method further comprises: receiving, from the network device, indication information sent by the first terminal device for indicating the second terminal device in a connected mode; and The first terminal device measures a second terminal device in a connection mode based on the indication information; A method in which the first terminal device transmits information of a candidate second terminal device (relay UE) to a network device based on the result of the measurement.

[0163] (Appendix 15) 1. A method for transmitting and receiving information, adapted for a network device, the method comprising: A method comprising: when a second terminal device enters a radio resource control connected (RRC_connected) mode, sending a radio resource control reconfiguration (RRC reconfiguration) message to the second terminal device, causing the second terminal device to perform relay-related settings of a PC5 interface and a Uu interface.

[0164] (Appendix 16) 16. The method of claim 15, The method further comprises: receiving indicator information transmitted by the second terminal device.

[0165] (Appendix 17) 17. The method of claim 16, comprising: A method in which the network device receives the indication information from the second terminal device via a Sidelink UE Information (SUI) message.

[0166] (Appendix 18) 17. The method of claim 16, comprising: A method in which the network device receives the indication information from the second terminal device via a Sidelink User Equipment Information (SUI) message before sending the Radio Resource Control reconfiguration (RRC reconfiguration) message.

[0167] (Appendix 19) A method for transmitting and receiving information, which is applied to a second terminal device (relay UE), the method comprising: The second terminal device in a radio resource control idle (RRC_idle) mode or a radio resource control inactive (RRC_inactive) mode receives a radio resource control reconfiguration complete (RRC reconfiguration complete) message transmitted by a first terminal device (remote UE) and enters a radio resource control connected (RRC_connected) mode; and A method comprising: receiving a radio resource control reconfiguration (RRC reconfiguration) message sent by a network device; and performing relay-related configuration of a PC5 interface and a Uu interface.

[0168] (Appendix 20) 20. The method of claim 19, further comprising: The method further comprises: The method includes the second terminal device transmitting indicator information to the network device.

[0169] (Appendix 21) 21. The method of claim 20, The method includes receiving the radio resource control reconfiguration (RRC reconfiguration) message after the second terminal device sends indicator information to the network device.

[0170] (Appendix 22) 21. The method of claim 20, The second terminal device transmits the indication information to the network device via a Sidelink UE Information (SUI) message.

[0171] (Appendix 23) 21. The method of claim 20, A method, wherein the condition for the second terminal device to transmit the indicator information includes receiving a radio resource control reconfiguration complete (RRC reconfiguration complete) message transmitted by the first terminal device.

[0172] (Appendix 24) 24. The method of claim 23, the radio resource control reconfiguration completion message is sent by the first terminal device to a network device via the second terminal device; or The SRB0 received by the second terminal device from the first terminal device over the PC5 interface carries the RRC reconfiguration complete message; or A method in which the second terminal device receives the radio resource control reconfiguration complete (RRC reconfiguration complete) message transmitted from the first terminal device via a PC5 interface using default settings.

Claims

1. An apparatus for transmitting and receiving information, which is applied to a network device, the apparatus includes a first transceiver unit, the first transceiver unit being configured as follows: receiving information of a second terminal device that is a candidate for transmission from the first terminal device; Send a radio resource control reconfiguration message to the first terminal device, where the radio resource control reconfiguration message includes information of a target second terminal device in a radio resource control connected mode; and communicating with the first terminal device by the target second terminal device.

2. 2. The apparatus of claim 1, An apparatus, wherein the first transceiver unit selects a candidate second terminal device in a radio resource control connection mode as the target second terminal device based on information of the candidate second terminal device transmitted by the first terminal device.

3. An apparatus according to claim 1 or 2, The first transceiver unit receives indication information of a second terminal device sending entering a radio resource control access mode; The first transceiver unit selects a candidate second terminal device in a radio resource control connection mode based on the indicator information and the information of the candidate second terminal device transmitted by the first terminal device.

4. 4. The apparatus of claim 3, The apparatus, wherein the labeling information is layer 2 labeling information.

5. 3. The device according to claim 1 or 2, the network device assigns identification information of the second terminal device; The first transceiver unit selects a candidate second terminal device in a radio resource control connection mode based on the indicator information and the information of the candidate second terminal device transmitted by the first terminal device.

6. 6. The apparatus of claim 5, The identification information is a cell radio network temporary identifier.

7. 7. The apparatus of claim 6, The first terminal device receives the indicator information transmitted by a second terminal device when the indicator information is a cell radio network temporary identifier.

8. 2. The apparatus of claim 1, The first transceiver unit receives information of a candidate second terminal device in a radio resource control connection mode of the first terminal device transmission.

9. 2. The apparatus of claim 1, The first transceiver unit is further configured as follows: Sending indication information to the first terminal device for indicating the second terminal device in a connection mode; The first terminal device measures the second terminal device in a connection mode according to the indication information; The first transceiver unit receives information of a candidate second terminal device that the first terminal device transmits based on the result of the measurement.

10. 2. The apparatus of claim 1, For a target second terminal device in a radio resource control connected mode, the first transceiver unit does not instruct the target second terminal device to enter a non-connected mode.

11. An apparatus for transmitting and receiving information, the apparatus being adapted for a first terminal device, the apparatus including a second transceiver unit, the second transceiver unit being configured as follows: Sending information of the candidate second terminal device to the network device; receiving a radio resource control reconfiguration message sent by the network device, the radio resource control reconfiguration message including information of a target second terminal device in a radio resource control connected mode; and communicating with said network device by said target second terminal device.

12. 12. The apparatus of claim 11, The second transceiver unit transmits information of a candidate second terminal device in a radio resource control connection mode to the network device.

13. 13. The apparatus of claim 12, The second transceiver unit is further configured as follows: receiving indication information transmitted by a second terminal device for indicating an RRC mode of the second terminal device; The second transceiver unit sends information of a candidate second terminal device in a radio resource control connection mode to the network device based on the indication information.

14. 12. The apparatus of claim 11, The second transceiver unit is further configured as follows: receiving, from the network device, indication information for indicating the second terminal device in a connected mode; and Measure the second terminal device in a connection mode according to the indication information; The second transceiver unit transmits information of a candidate second terminal device to a network device based on the result of the measurement.

15. An apparatus for transmitting and receiving information, the apparatus being applied to a second terminal device, the apparatus including a fifth transceiver unit, the fifth transceiver unit being configured as follows: When the second terminal device is in a radio resource control idle mode or a radio resource control inactive mode, the fifth transceiver unit receives a radio resource control reconfiguration completion message sent by the first terminal device, and causes the second terminal device to enter a radio resource control connected mode; and A device for receiving a radio resource control reconfiguration message sent by a network device, and causing the second terminal device to perform relay-related configuration of a PC5 interface and a Uu interface.

16. 16. The apparatus of claim 15, The fifth transceiver unit is further configured to transmit signature information to the network device.

17. 17. The apparatus of claim 16, After sending the indication information to the network device, the fifth transceiver unit receives the radio resource control reconfiguration message.

18. 17. The apparatus of claim 16, The fifth transceiver unit transmits the indicator information to the network device via a sidelink terminal device information message.

19. 17. The apparatus of claim 16, A device, wherein the condition for the fifth transceiver unit to transmit the indicator information includes the second terminal device receiving the radio resource control reconfiguration completion message transmitted by the first terminal device.

20. 20. The apparatus of claim 19, the radio resource control reconfiguration completion message is sent by the first terminal device to a network device via the second terminal device; or The SRB0 received by the fifth transceiver unit from the first terminal device over the PC5 interface carries the radio resource control reconfiguration complete message; or The fifth transceiver unit receives the radio resource control reconfiguration completion message sent by adopting default settings from the first terminal device via a PC5 interface.

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