Discovery method for relay user equipment (UE), and apparatus and storage medium

Abstract

The present disclosure relates to the technical field of communications, and in particular to a discovery method for a relay user equipment (UE), and an apparatus and a storage medium. The method is applied to a first relay UE, and comprises: receiving a discovery message; if a relay forwarding identifier represents that an end UE set allows a relay UE to perform forwarding, adding a user information identifier of the first relay UE to a first relay UE set; forwarding a discovery message to which the user information identifier of the first relay UE has been added, wherein the discovery message at least carries one or more of the following parameters: the end UE set, comprising a user information identifier of a source end UE and a user information identifier of a destination end UE; the first relay UE set, comprising user information identifiers of relay UEs between the source end UE and the first relay UE in the relay UE discovery process; and the relay forwarding identifier, used for representing whether the end UE set allows the relay UE to perform forwarding or not. The present disclosure can support the discovery of a multi-hop relay UE.

Description

Method, device and storage medium for discovering relay user equipment UE

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This disclosure claims priority to a Chinese patent application filed with the Patent Office of China on January 19, 2024, with application number 202410083763.0 and application name “Discovery Method, Device and Storage Medium for Relay User Equipment UE”, the entire contents of which are incorporated by reference into this disclosure. Technical Field

[0003] The present disclosure relates to the field of communication technology, and in particular to a method, device, and storage medium for discovering a relay user equipment (UE). Background Art

[0004] Currently, the R18 standard in the 3GPP (3rd Generation Partnership Project) protocol studies and standardizes ProSe (Proximity Services) scenarios in 5G (5th Generation Mobile Communication Technology) systems.

[0005] In the ProSe scenario, when two UEs (User Equipment) cannot communicate directly due to reasons such as long distance or poor signal quality, they can communicate through another UE as a relay. These two UEs are called End UEs, and the UE that acts as a relay is called a UE-to-UE Relay. The End UE communicates with the UE-to-UE Relay through the PC5 (Proximity Communication) interface. Before an End UE communicates with another End UE through a UE-to-UE Relay, it needs to first discover a suitable UE-to-UE Relay and then establish a connection through the UE-to-UE Relay.

[0006] However, the R18 standard only supports the End UE discovering a UE-to-UE Relay supporting a single hop, and does not support the End UE discovering a UE-to-UE Relay supporting a multi-hop. Summary of the Invention

[0007] Based on this, it is necessary to provide a method, device and storage medium for discovering a relay user equipment UE in order to address the above technical issues.

[0008] In a first aspect, a method for discovering a relay user equipment (UE) is provided. The method is applied to a first relay UE, and the method includes:

[0009] Receive discovery messages;

[0010] If the relay forwarding identifier represents that the end UE set allows the relay UE to forward, then add the user information identifier of the first relay UE to the first relay UE set;

[0011] Forwarding the discovery message with the user information identifier of the first relay UE added;

[0012] The discovery message carries at least one or more of the following parameters:

[0013] The end UE set includes a user information identifier of a source UE and a user information identifier of a destination UE;

[0014] The first relay UE set, wherein the first relay UE set includes user information identifiers of relay UEs passed by the source UE to reach the first relay UE during a relay UE discovery process;

[0015] The relay forwarding identifier is used to indicate whether the end UE set allows the relay UE to forward.

[0016] As an optional implementation manner, the receiving a discovery message includes:

[0017] Receive discovery announcement messages sent by other relay UEs;

[0018] Alternatively, a discovery request message sent by the source UE or other relay UE is received.

[0019] As an optional implementation manner, the discovery message further carries at least a hop count identifier, and the hop count identifier is used to represent the number of times the end UE set allows the relay UE to forward.

[0020] As an optional implementation manner, before adding the user information identifier of the first relay UE to the first relay UE set, the method further includes:

[0021] If the hop count identifier is not 0, decrement the hop count identifier by 1, and add the user information identifier of the first relay UE to the first relay UE set;

[0022] If the hop count identifier is 0, the discovery message is discarded.

[0023] As an optional implementation manner, the discovery message further carries at least an end UE set identifier, and the end UE set identifier is used to uniquely identify the end UE set.

[0024] As an optional implementation manner, before adding the user information identifier of the first relay UE to the first relay UE set, the method further includes:

[0025] If the first relay UE has not forwarded the end UE set identifier, storing the end UE set identifier locally and adding the user information identifier of the first relay UE to the first relay UE set;

[0026] If the first relay UE has forwarded the end UE set identifier, the discovery message is discarded.

[0027] As an optional implementation, the method further includes:

[0028] Receiving a discovery response message sent by the destination UE or the second relay UE;

[0029] Sending the discovery response message to the source UE or the third relay UE;

[0030] The discovery response message carries at least one or more of the following parameters:

[0031] The terminal UE set;

[0032] The second relay UE set includes the user information identifier of the relay UE passed by the source UE to reach the destination UE during the relay UE discovery process and the layer 2 identifier of the relay UE, the layer 2 identifier is used for the subsequent connection establishment process, the second relay UE is the relay UE after the first relay UE in the second relay UE set, and the third relay UE is the relay UE before the first relay UE in the relay UE set.

[0033] As an optional implementation, the method further includes:

[0034] Send a discovery announcement message; wherein the discovery announcement message carries at least one or more of the following parameters:

[0035] The end UE set, where the end UE set is the end UE set obtained by the first relay UE during the relay UE discovery process and / or the UE communication process;

[0036] a third relay UE set, wherein the third relay UE set at least includes user information identifiers of relay UEs passed by the source end UE in the end UE set to reach the first relay UE;

[0037] A relay forwarding identifier is used to indicate whether the end UE set allows the relay UE to forward.

[0038] As an optional implementation, the discovery announcement message also carries at least a hop count identifier, which is used to represent the number of times the end UE set allows the relay UE to forward. The hop count identifier is determined based on the initial hop count identifier and the number of hops corresponding to the source end UE in the end UE set reaching the first relay UE. The initial hop count identifier is determined by the first relay UE or the policy control function PPCF network element.

[0039] As an optional implementation, the discovery announcement message also carries at least an end UE set identifier, which is used to uniquely identify the end UE set, and the end UE set identifier is generated by the first relay UE or CF network element based on the end UE set.

[0040] As an optional implementation, the method further includes:

[0041] Sending a registration request message to the access and mobility management function AMF network element; wherein the registration request message carries at least a proximity service capability parameter, the proximity service capability parameter includes the end UE set and / or a multi-hop relay identifier, and the multi-hop relay identifier is used to indicate that the first relay UE supports a discovery function of a multi-hop relay UE;

[0042] A non-access layer NAS message sent by the PCF network element is received through the AMF network element; wherein the NAS message carries at least a proximity service policy parameter, and the proximity service policy parameter includes a user information identifier, an end UE set identifier and / or a hop count identifier of the first relay UE.

[0043] In a second aspect, a method for discovering a relay user equipment (UE) is provided, the method being applied to an end UE, the method including:

[0044] Send a first discovery request message; wherein the first discovery request message carries at least one or more of the following parameters:

[0045] A first-end UE set, the first-end UE set including a user information identifier of a source-end UE and a user information identifier of a destination-end UE; the end UE is a source-end UE in the first-end UE set;

[0046] a first relay UE set;

[0047] A relay forwarding identifier, where the relay forwarding identifier is used to indicate whether the first-end UE set allows the relay UE to forward.

[0048] As an optional implementation, the method further includes:

[0049] receiving a second discovery request message sent by the relay UE;

[0050] If the destination UE in the second-end UE set includes the end UE, sending a discovery response message to the relay UE;

[0051] The second discovery request message carries at least one or more of the following parameters:

[0052] A second-end UE set, where the second-end UE set includes a user information identifier of a source UE and a user information identifier of a destination UE, and the end UE is a destination UE in the second-end UE set;

[0053] A second relay UE set, wherein the second relay UE set includes at least user information identifiers of relay UEs passed through by the source UE to the destination UE in the second end UE set;

[0054] The discovery response message carries at least one or more of the following parameters;

[0055] the second-end UE set;

[0056] The second relay UE set.

[0057] As an optional implementation, the first discovery request message also carries at least a hop count identifier, which is used to represent the number of times the first-end UE set allows the relay UE to forward, and the hop count identifier is determined by the end UE or the policy control function PCF network element.

[0058] As an optional implementation, the first discovery request message also carries at least an end UE set identifier, which is used to uniquely identify the first end UE set, and the end UE set identifier is generated by the end UE or PCF network element based on the first end UE set.

[0059] As an optional implementation, the method further includes:

[0060] Sending a registration request message to the access and mobility management function AMF network element; wherein the registration request message carries at least a proximity service capability parameter, the proximity service capability parameter includes the first-end UE set and / or a multi-hop relay identifier, and the multi-hop relay identifier is used to indicate that the end UE supports the discovery function of the multi-hop relay UE;

[0061] A non-access layer NAS message sent by the PCF network element is received through the AMF network element; wherein the NAS message carries at least a proximity service policy parameter, and the proximity service policy parameter includes at least a user information identifier of the end UE, an end UE set identifier and / or a hop count identifier.

[0062] In a third aspect, a method for discovering a relay user equipment (UE) is provided, the method being applied to an access and mobility management function (AMF) network element, the method comprising:

[0063] Receive a registration request message sent by the UE;

[0064] Sending a first non-access stratum (NAS) message to a policy control function (PCF) network element;

[0065] receiving a second NAS message sent by the PCF network element;

[0066] Sending a third NAS message to the UE;

[0067] The registration request message carries at least a proximity service capability parameter, the proximity service capability parameter includes an end UE set and / or a multi-hop relay identifier, and the multi-hop relay identifier is used to indicate that the UE supports a discovery function of a multi-hop relay UE;

[0068] The first NAS message carries at least the proximity service capability parameter;

[0069] The second NAS message carries at least a proximity service policy parameter, where the proximity service policy parameter includes a user information identifier, a terminal UE set identifier, and / or a hop count identifier of the UE;

[0070] The third NAS message carries the proximity service policy parameter.

[0071] In a fourth aspect, a method for discovering a relay user equipment (UE) is provided, the method being applied to a policy control function (PCF) network element, the method comprising:

[0072] Receive the first non-access stratum NAS message sent by the access and mobility management function AMF network element;

[0073] Sending a second NAS message to the AMF network element;

[0074] The first NAS message carries at least a proximity service capability parameter, the proximity service capability parameter includes a terminal UE set and / or a multi-hop relay identifier, and the multi-hop relay identifier is used to indicate that the UE supports a discovery function of a multi-hop relay UE;

[0075] The second NAS message carries at least a proximity service policy parameter, where the proximity service policy parameter includes a user information identifier of the UE, an end UE set identifier, and / or a hop count identifier, and the end UE set identifier is generated based on the end UE set.

[0076] In a fifth aspect, a relay user equipment (UE) is provided, comprising a memory, a transceiver, and a processor, wherein the memory is configured to store a computer program; the transceiver is configured to transmit and receive data under the control of the processor; and the processor is configured to read the computer program in the memory and perform the following operations:

[0077] Receive discovery messages;

[0078] If the relay forwarding identifier represents that the end UE set allows the relay UE to forward, then add the user information identifier of the first relay UE to the first relay UE set;

[0079] Forwarding the discovery message with the user information identifier of the first relay UE added;

[0080] The discovery message carries at least one or more of the following parameters:

[0081] The end UE set includes a user information identifier of a source UE and a user information identifier of a destination UE;

[0082] The first relay UE set, wherein the first relay UE set includes user information identifiers of relay UEs passed by the source UE to reach the first relay UE during a relay UE discovery process;

[0083] The relay forwarding identifier is used to indicate whether the end UE set allows the relay UE to forward.

[0084] As an optional implementation manner, the receiving a discovery message includes:

[0085] Receive discovery announcement messages sent by other relay UEs;

[0086] Alternatively, a discovery request message sent by the source UE or other relay UE is received.

[0087] As an optional implementation manner, the discovery message further carries at least a hop count identifier, and the hop count identifier is used to represent the number of times the end UE set allows the relay UE to forward.

[0088] As an optional implementation manner, before adding the user information identifier of the first relay UE to the first relay UE set, the processor is further configured to perform the following operations:

[0089] If the hop count identifier is not 0, decrement the hop count identifier by 1, and add the user information identifier of the first relay UE to the first relay UE set;

[0090] If the hop count identifier is 0, the discovery message is discarded.

[0091] As an optional implementation manner, the discovery message further carries at least an end UE set identifier, and the end UE set identifier is used to uniquely identify the end UE set.

[0092] As an optional implementation manner, before adding the user information identifier of the first relay UE to the first relay UE set, the processor is further configured to perform the following operations:

[0093] If the first relay UE has not forwarded the end UE set identifier, storing the end UE set identifier locally and adding the user information identifier of the first relay UE to the first relay UE set;

[0094] If the first relay UE has forwarded the end UE set identifier, the discovery message is discarded.

[0095] As an optional implementation manner, the processor is further configured to perform the following operations:

[0096] Receiving a discovery response message sent by the destination UE or the second relay UE;

[0097] Sending the discovery response message to the source UE or the third relay UE;

[0098] The discovery response message carries at least one or more of the following parameters:

[0099] The terminal UE set;

[0100] The second relay UE set includes the user information identifier of the relay UE passed by the source UE to reach the destination UE during the relay UE discovery process and the layer 2 identifier of the relay UE, the layer 2 identifier is used for the subsequent connection establishment process, the second relay UE is the relay UE after the first relay UE in the second relay UE set, and the third relay UE is the relay UE before the first relay UE in the relay UE set.

[0101] As an optional implementation manner, the processor is further configured to perform the following operations:

[0102] Send a discovery announcement message; wherein the discovery announcement message carries at least one or more of the following parameters:

[0103] The end UE set, where the end UE set is the end UE set obtained by the first relay UE during the relay UE discovery process and / or the UE communication process;

[0104] a third relay UE set, wherein the third relay UE set at least includes user information identifiers of relay UEs passed by the source end UE in the end UE set to reach the first relay UE;

[0105] A relay forwarding identifier is used to indicate whether the end UE set allows the relay UE to forward.

[0106] As an optional implementation, the discovery announcement message also carries at least a hop count identifier, which is used to represent the number of times the end UE set allows the relay UE to forward. The hop count identifier is determined based on the initial hop count identifier and the number of hops corresponding to the source end UE in the end UE set reaching the first relay UE. The initial hop count identifier is determined by the first relay UE or the policy control function PCF network element.

[0107] As an optional implementation, the discovery announcement message also carries at least an end UE set identifier, which is used to uniquely identify the end UE set, and the end UE set identifier is generated by the first relay UE or PCF network element based on the end UE set.

[0108] As an optional implementation manner, the processor is further configured to perform the following operations:

[0109] Sending a registration request message to the access and mobility management function AMF network element; wherein the registration request message carries at least a proximity service capability parameter, the proximity service capability parameter includes the end UE set and / or a multi-hop relay identifier, and the multi-hop relay identifier is used to indicate that the first relay UE supports a discovery function of a multi-hop relay UE;

[0110] A non-access layer NAS message sent by the PCF network element is received through the AMF network element; wherein the NAS message carries at least a proximity service policy parameter, and the proximity service policy parameter includes a user information identifier, an end UE set identifier and / or a hop count identifier of the first relay UE.

[0111] In a sixth aspect, an end user equipment (UE) is provided, comprising a memory, a transceiver, and a processor, wherein the memory is configured to store a computer program; the transceiver is configured to transmit and receive data under the control of the processor; and the processor is configured to read the computer program in the memory and perform the following operations:

[0112] Send a first discovery request message; wherein the first discovery request message carries at least one or more of the following parameters:

[0113] A first-end UE set, where the first-end UE set includes a user information identifier of a source-end UE and a user information identifier of a destination-end UE, and the end UE is a source-end UE in the first-end UE set;

[0114] a first relay UE set;

[0115] A relay forwarding identifier, where the relay forwarding identifier is used to indicate whether the first-end UE set allows the relay UE to forward.

[0116] As an optional implementation manner, the processor is further configured to perform the following operations:

[0117] receiving a second discovery request message sent by the relay UE;

[0118] If the destination UE in the second-end UE set includes the end UE, sending a discovery response message to the relay UE;

[0119] The second discovery request message carries at least one or more of the following parameters:

[0120] A second-end UE set, where the second-end UE set includes a user information identifier of a source UE and a user information identifier of a destination UE, and the end UE is a destination UE in the second-end UE set;

[0121] a second relay UE set, wherein the second relay UE set includes at least user information identifiers of relay UEs passed through by the source UE to the destination UE in the second end UE set;

[0122] The discovery response message carries at least one or more of the following parameters;

[0123] the second-end UE set;

[0124] The second relay UE set.

[0125] As an optional implementation, the first discovery request message also carries at least a hop count identifier, which is used to represent the number of times the first-end UE set allows the relay UE to forward; the hop count identifier is determined by the end UE or the policy control function PCF network element.

[0126] As an optional implementation, the first discovery request message also carries at least an end UE set identifier, which is used to uniquely identify the first end UE set; the end UE set identifier is generated by the end UE or PCF network element based on the first end UE set.

[0127] As an optional implementation manner, the processor is further configured to perform the following operations:

[0128] Sending a registration request message to the access and mobility management function AMF network element; wherein the registration request message carries at least a proximity service capability parameter, the proximity service capability parameter includes the first-end UE set and / or a multi-hop relay identifier, and the multi-hop relay identifier is used to indicate that the end UE supports the discovery function of the multi-hop relay UE;

[0129] A non-access layer NAS message sent by the PCF network element is received through the AMF network element; wherein the NAS message carries at least a proximity service policy parameter, and the proximity service policy parameter includes at least a user information identifier of the end UE, an end UE set identifier and / or a hop count identifier.

[0130] In a seventh aspect, an access and mobility management function (AMF) network element is provided, comprising a memory, a transceiver, and a processor, wherein the memory is used to store a computer program; the transceiver is used to send and receive data under the control of the processor; and the processor is used to read the computer program in the memory and perform the following operations:

[0131] Receive a registration request message sent by the UE;

[0132] Sending a first non-access stratum (NAS) message to a policy control function (PCF) network element;

[0133] receiving a second NAS message sent by the PCF network element;

[0134] Sending a third NAS message to the UE;

[0135] The registration request message carries at least a proximity service capability parameter, the proximity service capability parameter includes an end UE set and / or a multi-hop relay identifier, and the multi-hop relay identifier is used to indicate that the UE supports a discovery function of a multi-hop relay UE;

[0136] The first NAS message carries at least the proximity service capability parameter;

[0137] The second NAS message carries at least a proximity service policy parameter, where the proximity service policy parameter includes a user information identifier, a terminal UE set identifier, and / or a hop count identifier of the UE;

[0138] The third NAS message carries the proximity service policy parameter.

[0139] In an eighth aspect, a policy control function (PCF) network element is provided, comprising a memory, a transceiver, and a processor, wherein the memory is configured to store a computer program; the transceiver is configured to transmit and receive data under the control of the processor; and the processor is configured to read the computer program in the memory and perform the following operations:

[0140] Receive the first non-access stratum NAS message sent by the access and mobility management function AMF network element;

[0141] Sending a second NAS message to the AMF network element;

[0142] The first NAS message carries at least a proximity service capability parameter, the proximity service capability parameter includes a terminal UE set and / or a multi-hop relay identifier, and the multi-hop relay identifier is used to indicate that the UE supports a discovery function of a multi-hop relay UE;

[0143] The second NAS message carries at least a proximity service policy parameter, where the proximity service policy parameter includes a user information identifier of the UE, an end UE set identifier, and / or a hop count identifier, and the end UE set identifier is generated based on the end UE set.

[0144] In a ninth aspect, a discovery apparatus for a relay user equipment UE is provided, the apparatus being applied to a first relay UE, the apparatus including:

[0145] A first receiving unit, configured to receive a discovery message;

[0146] An adding unit, configured to add a user information identifier of the first relay UE to the first relay UE set if the relay forwarding identifier represents that the end UE set allows the relay UE to forward;

[0147] A first sending unit, configured to forward the discovery message with the user information identifier of the first relay UE added;

[0148] The discovery message carries at least one or more of the following parameters:

[0149] The end UE set includes a user information identifier of a source UE and a user information identifier of a destination UE;

[0150] The first relay UE set, wherein the first relay UE set includes user information identifiers of relay UEs passed by the source UE to reach the first relay UE during a relay UE discovery process;

[0151] The relay forwarding identifier is used to indicate whether the end UE set allows the relay UE to forward.

[0152] In a tenth aspect, a discovery device for a relay user equipment (UE) is provided, the device being applied to a terminal UE, the device including:

[0153] The first sending unit is configured to send a first discovery request message, wherein the first discovery request message carries at least one or more of the following parameters:

[0154] A first-end UE set, where the first-end UE set includes a user information identifier of a source-end UE and a user information identifier of a destination-end UE, and the end UE is a source-end UE in the first-end UE set;

[0155] a first relay UE set;

[0156] A relay forwarding identifier, where the relay forwarding identifier is used to indicate whether the first-end UE set allows the relay UE to forward.

[0157] In an eleventh aspect, a discovery device for a relay user equipment UE is provided, the device being applied to an access and mobility management function AMF network element, the device comprising:

[0158] A first receiving unit, configured to receive a registration request message sent by a UE;

[0159] A first sending unit, configured to send a first non-access stratum NAS message to a policy control function PCF network element;

[0160] A second receiving unit, configured to receive a second NAS message sent by the PCF network element;

[0161] A second sending unit, configured to send a third NAS message to the UE;

[0162] The registration request message carries at least a proximity service capability parameter, the proximity service capability parameter includes an end UE set and / or a multi-hop relay identifier, and the multi-hop relay identifier is used to indicate that the UE supports a discovery function of a multi-hop relay UE;

[0163] The first NAS message carries at least the proximity service capability parameter;

[0164] The second NAS message carries at least a proximity service policy parameter, where the proximity service policy parameter includes a user information identifier, a terminal UE set identifier, and / or a hop count identifier of the UE;

[0165] The third NAS message carries the proximity service policy parameter.

[0166] In a twelfth aspect, a discovery device for a relay user equipment (UE) is provided, the device being applied to a policy control function (PCF) network element, the device including:

[0167] A receiving unit, configured to receive a first non-access stratum NAS message sent by an access and mobility management function AMF network element;

[0168] a sending unit, configured to send a second NAS message to the AMF network element;

[0169] The first NAS message carries at least a proximity service capability parameter, the proximity service capability parameter includes a terminal UE set and / or a multi-hop relay identifier, and the multi-hop relay identifier is used to indicate that the UE supports a discovery function of a multi-hop relay UE;

[0170] The second NAS message carries at least a proximity service policy parameter, where the proximity service policy parameter includes a user information identifier of the UE, an end UE set identifier, and / or a hop count identifier, and the end UE set identifier is generated based on the end UE set.

[0171] In the thirteenth aspect, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps of the method described in the first aspect, the second aspect, the third aspect, or the fourth aspect are implemented.

[0172] In the fourteenth aspect, a communication system is provided, which includes a relay user equipment UE, an end UE, a mobility management function AMF network element and a policy control function PCF network element, the relay UE performs the steps of the method described in the first aspect, the end UE performs the steps of the method described in the second aspect, the AMF network element performs the steps of the method described in the third aspect, and the PCF network element performs the steps of the method described in the fourth aspect.

[0173] The present disclosure provides a method, device and storage medium for discovering a relay user equipment UE. The technical solution provided by the embodiments of the present disclosure brings at least the following beneficial effects: the embodiments of the present disclosure can realize the multi-hop relay UE discovery process of the Model B mode initiated by the end UE and the multi-hop relay UE discovery process of the Model A mode initiated by the relay UE.

[0174] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0175] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or related technologies, the following briefly introduces the drawings required for use in the embodiments or related technical descriptions. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0176] FIG1 is an architecture diagram of an existing one-hop ProSe scenario provided by an embodiment of the present disclosure;

[0177] FIG2 is a signaling diagram of an existing relay UE discovery process provided by an embodiment of the present disclosure;

[0178] FIG3 is a signaling diagram of another existing relay UE discovery process provided by an embodiment of the present disclosure;

[0179] FIG4 is an architecture diagram of a multi-hop ProSe scenario provided by an embodiment of the present disclosure;

[0180] FIG5 is a flowchart of a method for discovering a relay UE provided in an embodiment of the present disclosure;

[0181] FIG6 is an architecture diagram of a multi-hop ProSe scenario provided by an embodiment of the present disclosure;

[0182] FIG7 is a flowchart of a method for discovering a relay UE provided in an embodiment of the present disclosure;

[0183] FIG8 is a flowchart of a method for discovering a relay UE provided in an embodiment of the present disclosure;

[0184] FIG9 is a flowchart of a method for discovering a relay UE provided in an embodiment of the present disclosure;

[0185] FIG10 is a flowchart of a method for discovering a relay UE provided in an embodiment of the present disclosure;

[0186] FIG11 is a flowchart of Example 1 of a method for discovering a relay UE provided by an embodiment of the present disclosure;

[0187] FIG12 is a flowchart of Example 2 of a method for discovering a relay UE provided in an embodiment of the present disclosure;

[0188] FIG13 is a flowchart of a method for discovering a relay UE provided in an embodiment of the present disclosure;

[0189] FIG14 is a flowchart of a method for discovering a relay UE provided in an embodiment of the present disclosure;

[0190] FIG15 is a flowchart of a method for discovering a relay UE provided in an embodiment of the present disclosure;

[0191] FIG16 is a flowchart of a method for discovering a relay UE provided in an embodiment of the present disclosure;

[0192] FIG17 is a flowchart of Example 3 of a method for discovering a relay UE provided by an embodiment of the present disclosure;

[0193] FIG18 is a schematic structural diagram of a relay UE provided in an embodiment of the present disclosure;

[0194] FIG19 is a schematic structural diagram of a terminal UE provided in an embodiment of the present disclosure;

[0195] FIG20 is a schematic diagram of the structure of an AMF network element provided in an embodiment of the present disclosure;

[0196] FIG21 is a schematic diagram of the structure of a PCF network element provided in an embodiment of the present disclosure;

[0197] FIG22 is a schematic structural diagram of a discovery device for a relay UE provided in an embodiment of the present disclosure;

[0198] FIG23 is a schematic structural diagram of a discovery device for a relay UE provided in an embodiment of the present disclosure;

[0199] FIG24 is a schematic structural diagram of a discovery device for a relay UE provided in an embodiment of the present disclosure;

[0200] FIG25 is a structural diagram of a discovery device for a relay UE provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0201] The following will be combined with the accompanying drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the embodiments described are only part of the embodiments of the present disclosure and not all of the embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present disclosure.

[0202] In the embodiments of the present disclosure, the term "and / or" describes the relationship between associated objects, indicating that three possible relationships exist. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. The character " / " generally indicates that the associated objects are in an "or" relationship. In the embodiments of the present disclosure, the term "plurality" refers to two or more, and other quantifiers are similar.

[0203] Figure 1 is an architecture diagram of an existing one-hop ProSe scenario provided by an embodiment of the present disclosure. As shown in Figure 1, the existing ProSe scenario includes end UE1, relay UE, and end UE2. In the existing ProSe scenario, end UE1 and end UE2 only support communication through the one-hop relay UE.

[0204] The relay UE discovery process defined in the R18 standard of the existing 3GPP protocol supports two modes, which are as follows.

[0205] (1) Mode A, as shown in Figure 2, the specific steps are as follows.

[0206] In step 201, the relay UE obtains the end UE set {User Info ID of end UE1, User Info ID of end UE2} during the relay UE discovery process and / or UE communication process. The end UE set is an encrypted set that can only be parsed by end UE1 and end UE2, but not by the relay UE.

[0207] In step 202, the relay UE sends a Discovered Announcement message. The Discovered Announcement message includes parameters such as the end UE set {User Info ID of end UE1, User Info ID of end UE2}, the relay UE's User Info ID, and the Relay Service Code (RSC). The RSC is used to identify the services supported by the relay UE.

[0208] (2) Mode B, as shown in Figure 3, the specific steps are as follows.

[0209] Step 301: UE1 sends a Discovery Solicitation message, which includes parameters such as the UE set {User Info ID of UE1, User Info ID of UE2} and RSC.

[0210] In step 302, if the RSC stored locally by the relay UE matches the RSC carried in the discovery request message, the relay UE forwards the discovery request message, which includes parameters such as the set of end UEs {User Info ID of end UE1, User Info ID of end UE2}, the User Info ID of the relay UE, and the RSC.

[0211] In step 302, if the RSC stored locally by UE2 matches the RSC carried in the discovery request message, and the User Info ID of UE2 matches the User Info ID of UE2 in the UE set carried in the discovery request message, UE2 sends a discovery response message (Discovered Response message) to the relay UE. The discovery response message includes parameters such as the UE set {User Info ID of UE1, User Info ID of UE2} and the RSC.

[0212] In step 303, if the RSC stored locally by the relay UE matches the RSC carried in the discovery response message, the relay UE sends a discovery response message to the end UE1. The discovery response message includes parameters such as the end UE set {User Info ID of end UE1, User Info ID of end UE2}, the relay UE's User Info ID, and the RSC.

[0213] In existing ProSe scenarios, the source UE (i.e., end UE1 in the end UE set) communicates with the destination UE (i.e., end UE2 in the end UE set) through a relay UE, which can extend the communication range and save UE power. It is an important form of communication in public safety and commercial applications. In some scenarios, such as in a basement or a forest, the source UE is often unable to communicate with the destination UE through a one-hop relay UE. In this case, the source UE often needs to communicate with the destination UE through a multi-hop relay UE. The R18 standard studies and standardizes the discovery process of the end UE through a one-hop relay UE, but how the end UE discovers the destination UE through a multi-hop relay UE is an unresolved issue in the R18 standard.

[0214] FIG4 is an architectural diagram of a multi-hop ProSe scenario provided by an embodiment of the present disclosure. As shown in FIG4 , for Mode B of an existing ProSe scenario, the ProSe scenario of the present disclosure includes end UE1, relay UE1, relay UE2, relay UE3, and end UE2. In the ProSe scenario of the present disclosure, end UE1 and end UE2 communicate via a multi-hop relay UE. The present embodiment of the disclosure uses a 2-hop relay UE discovery process as an example, but the present embodiment of the disclosure is applicable to an n-hop relay UE discovery process (n>=2).

[0215] For Mode B of the existing ProSe scenario, the present disclosure provides a method for discovering a relay UE. The method is performed by an end UE, which may be end UE1 or end UE2 in Figure 4. As shown in Figure 5, the specific steps are as follows:

[0216] Step 501: Send a first discovery request message. The first discovery request message carries at least one or more of the following parameters: a first-end UE set, where the first-end UE set includes a user information identifier of a source UE and a user information identifier of a destination UE, and the destination UE is a source UE in the first-end UE set; a first relay UE set; and a relay forwarding identifier, which indicates whether the first-end UE set allows the relay UE to forward.

[0217] In implementation, in conjunction with Figure 4, when the end UE is a source end UE (i.e., end UE1 in Figure 4), the end UE sends a first discovery request message by broadcasting. The first discovery request message carries at least one or more of the first end UE set, the first relay UE set, and the relay forwarding identifier (relay allowed indication). Among them, the first end UE set includes the user information identifier of the source end UE and the user information identifier of the destination end UE, such as {User Info ID of end UE1, User Info ID of end UE2}; since the end UE is a source end UE, the first relay UE set is empty at this time; the relay forwarding identifier is used to indicate whether the first end UE set allows the relay UE to forward, that is, whether the first end UE set supports the multi-hop relay UE discovery function. Optionally, the first discovery request message also carries at least RSC.

[0218] As an optional implementation, in order to limit the scope of discovery by the relay UE, the first discovery request message also carries at least a hop count identifier. The hop count identifier is used to represent the number of times the first-end UE set allows the relay UE to forward, and the hop count identifier is determined by the end UE or PCF (Policy Control Function) network element.

[0219] In implementation, in order to limit the scope of discovery by the relay UE, the first discovery request message also carries at least a hop indication. The hop indication is used to represent the number of times the first-end UE set allows the relay UE to forward. The hop indication is determined by the end UE or the PCF network element. Each time the first discovery request message is forwarded, the relay UE decrements the hop indication by 1 until the hop indication is reduced to 0, and the first discovery request message is no longer forwarded. The process of limiting the scope of discovery by the relay UE based on the hop indication carried in the discovery request message will be described in detail later and will not be repeated here.

[0220] As an optional implementation, in order to solve the problem of discovery request message flooding, the first discovery request message also carries at least an end UE set identifier. The end UE set identifier is used to uniquely identify the first end UE set, and the end UE set identifier is generated by the end UE or the PCF network element based on the first end UE set.

[0221] In implementation, in the multi-hop relay discovery process, since the relay UE can forward the first discovery request message by broadcasting, the first discovery request message has a flooding problem. In order to solve the problem of discovery request message flooding, the first discovery request message also carries at least an end UE set identifier (set indication). The end UE set identifier is used to uniquely identify the first end UE set. In order to uniquely identify the first end UE set, the end UE set identifier is generated by the end UE or PCF network element based on the first end UE set. In this way, different discovery request messages carry different end UE set identifiers, thereby solving the problem of discovery request message flooding while preventing the discovery request message from being erroneously discarded. Among them, the processing process of the relay UE to solve the problem of discovery request message flooding based on the end UE set identifier carried in the discovery request message will be introduced in detail later and will not be repeated here.

[0222] It should be noted that the relay forwarding identifier and hop count identifier can be implemented through a relay identifier (relay indication). When the first discovery request message carries a relay identifier, it indicates that the first discovery request message allows the relay UE to forward it. At the same time, each time the first discovery request message is forwarded, the relay UE decrements the value of the relay identifier by 1 until the value of the relay identifier is reduced to 0, and the first discovery request message is no longer forwarded. The relay identifier is determined by the end UE or PCF network element.

[0223] FIG6 is an architecture diagram of a multi-hop ProSe scenario provided by an embodiment of the present disclosure. As shown in FIG6 , for Mode A of an existing ProSe scenario, the ProSe scenario of the present disclosure includes relay UE1, relay UE2, relay UE3, relay UE4, relay UE5, end UE1, and end UE2. The present disclosure uses a 4-hop relay UE discovery process as an example, but the present disclosure is applicable to an n-hop relay UE discovery process (n>=2).

[0224] For Mode A of the existing ProSe scenario, the present disclosure provides a method for discovering a relay UE. The method is performed by a first relay UE, which may be relay UE1, relay UE2, relay UE3, relay UE4, and relay UE5 in Figure 6. As shown in Figure 7, the specific steps are as follows:

[0225] Step 701, sending a discovery announcement message; wherein, the discovery announcement message carries at least one or more of the following parameters: an end UE set, the end UE set is the end UE set obtained by the first relay UE in the relay UE discovery process and / or the UE communication process; a third relay UE set, the third relay UE set at least includes the user information identifier of the relay UE passed by the source end UE in the end UE set to reach the first relay UE; a relay forwarding identifier, the relay forwarding identifier is used to indicate whether the end UE set allows the relay UE to forward.

[0226] In implementation, in combination with FIG6 , when the first relay UE is the relay UE1 in FIG6 , the first relay UE can send a discovery announcement message by broadcasting. The discovery announcement message carries an end UE set, a third relay UE set and a relay forwarding identifier. Among them, the end UE set is the end UE set obtained by the first relay UE in the relay UE discovery process and / or the UE communication process, such as {User Info ID of end UE1, User Info ID of end UE2}; the third relay UE set at least includes the UserInfo ID of the relay UEs passed by the source end UE in the end UE set to reach the first relay UE, such as the third relay UE set is {User Info ID of relay UE5, User Info ID of relay UE1}; the relay forwarding identifier is used to indicate whether the end UE set allows the relay UE to forward. Optionally, the discovery announcement message also carries at least RSC.

[0227] As an optional implementation, in order to limit the scope of relay UE discovery, it is discovered that the announcement message also carries at least a hop count identifier, which is used to represent the number of times the end UE set allows the relay UE to forward. The hop count identifier is determined based on the initial hop count identifier and the number of hops corresponding to the source end UE in the end UE set reaching the first relay UE. The initial hop count identifier is determined by the first relay UE or PCF network element.

[0228] In implementation, in order to limit the scope of discovery by the relay UE, the discovery announcement message also carries at least a hop count identifier. The hop count identifier is used to characterize the number of times the end UE set allows the relay UE to forward. The hop count identifier is obtained by subtracting the hop count corresponding to the source end UE in the end UE set to reach the first relay UE based on the initial hop count identifier. The initial hop count is determined by the first relay UE or the PCF network element. For example, in conjunction with Figure 6, the initial hop count is 4, the relay UE1 passes through the relay UE5 to reach the end UE1, the hop count is 1, and the hop count identifier is 3. Each time the discovery announcement message is forwarded, the relay UE will reduce the hop count identifier by 1 until the hop count identifier is reduced to 0, and the discovery announcement message will no longer be forwarded. Among them, the processing process of the relay UE limiting the scope of discovery of the relay UE based on the hop count identifier carried in the discovery announcement message will be introduced in detail later and will not be repeated here.

[0229] It should be noted that the relay forwarding indicator and hop count indicator can be implemented through a relay indicator (relay indication). When a discovery announcement message carries a relay indicator, it indicates that the discovery announcement message allows the relay UE to forward it. At the same time, each time the discovery announcement message is forwarded, the relay UE decrements the relay indicator value by 1 until the relay indicator value reaches 0 and no longer forwards the discovery announcement message. The relay indicator is determined by the relay UE or PCF network element.

[0230] As an optional implementation, in order to solve the problem of discovery announcement message flooding, the discovery announcement message also carries at least an end UE set identifier. The end UE set identifier is used to uniquely identify the end UE set, and the end UE set identifier is generated by the first relay UE or PCF network element based on the end UE set.

[0231] In implementation, in the multi-hop relay discovery process, since the relay UE can forward the discovery announcement message by broadcasting, the discovery announcement message has a flooding problem. In order to solve the problem of discovery announcement message flooding, the discovery announcement message also carries at least an end UE set identifier. The end UE set identifier is used to uniquely identify the end UE set. In order to uniquely identify the end UE set, the end UE set identifier is generated by the first relay UE or PCF network element based on the end UE set. In this way, the end UE set identifiers carried in different discovery announcement messages are different, thereby solving the problem of discovery announcement message flooding while preventing the discovery announcement message from being erroneously discarded. Among them, the processing process of the relay UE to solve the problem of discovery announcement message flooding based on the end UE set identifier carried in the discovery announcement message will be introduced in detail later and will not be repeated here.

[0232] For Mode A and Mode B of existing ProSe scenarios, the present disclosure provides a method for discovering a relay UE. The method is performed by a first relay UE, which can be relay UE1, relay UE2, and relay UE3 in Figure 4, or relay UE2, relay UE3, relay UE4, and relay UE5 in Figure 6. As shown in Figure 8, the specific steps are as follows:

[0233] Step 801: Receive a discovery message. The discovery message carries at least one or more of the following parameters: an end UE set, which includes the user information identifiers of the source UE and the destination UE; a first relay UE set, which includes the user information identifiers of the relay UEs that the source UE passes through to reach the first relay UE during the relay UE discovery process; and a relay forwarding identifier, which indicates whether the end UE set allows the relay UE to forward.

[0234] In implementation, the first relay UE receives a discovery message. The discovery message carries at least one or more of the following parameters: an end UE set, a first relay UE set, and a relay forwarding identifier. The end UE set includes the user information identifier of the source UE and the user information identifier of the destination UE; the first relay UE set includes the user information identifiers of the relay UEs that the source UE passes through during the relay UE discovery process; and the relay forwarding identifier indicates whether the end UE set allows the relay UE to forward. Optionally, the discovery message also carries at least an RSC.

[0235] As an optional implementation, the discovery mode (ie, Mode A and Mode B) of the first relay UE is different, and the received discovery message is also different. There are two specific cases, as follows:

[0236] Case 1: When the first relay UE is in the first discovery mode (Mode A), it receives discovery announcement messages sent by other relay UEs.

[0237] In implementation, in combination with what is shown in FIG6 , when the first relay UE is relay UE2, relay UE3, relay UE4, and relay UE5 in FIG6 , the first relay UE can receive discovery announcement messages sent by other relay UEs. The end UE set in the discovery announcement message is {User Info ID of end UE1, User Info ID of end UE2}; when the first relay UE is relay UE2 in FIG6 , the first relay UE set is {User Info ID of relay UE5, User Info ID of relay UE1}. When the first relay UE is relay UE3 or relay UE4 in FIG6 , the first relay UE set is {User Info ID of relay UE5, User Info ID of relay UE1, User Info ID of relay UE2}.

[0238] Case 2: When the first relay UE is in the second discovery mode (Mode B), it receives a discovery request message sent by the source UE or other relay UEs.

[0239] In implementation, in combination with Figure 4, the discovery request message received by the first relay UE may be sent by the end UE (for example, the discovery request message received by relay UE1 and relay UE2 is sent by end UE1). At this time, the end UE set in the discovery request message is {User Info ID of end UE1, User Info ID of end UE2}; the first relay UE set is empty. The discovery request message received by the first relay UE may also be forwarded by the relay UE (for example, the discovery request message received by relay UE3 is forwarded by relay UE1 and relay UE2). The end UE set in the discovery request message is {User Info ID of end UE1, User Info ID of end UE2}; in the discovery request message forwarded by relay UE1 received by relay UE3, the first relay UE set is {User Info ID of relay UE1}. Similarly, in the discovery request message forwarded by relay UE2 received by relay UE3, the first relay UE set is {User Info ID of relay UE2}.

[0240] Step 802: If the relay forwarding identifier indicates that the end UE set allows the relay UE to forward, then the user information identifier of the first relay UE is added to the first relay UE set.

[0241] In implementation, the first relay UE determines whether the relay forwarding identifier indicates that the end UE set allows the relay UE to forward. If the relay forwarding identifier indicates that the end UE set allows the relay UE to forward, the first relay UE adds its user info ID to the first relay UE set.

[0242] For example, in conjunction with Figure 4, when relay UE3 receives a discovery request message forwarded by relay UE1, the first relay UE set after adding the user info ID of the first relay UE is {relay UE1's User Info ID, relay UE3's User Info ID}. Similarly, when relay UE3 receives a discovery request message forwarded by relay UE2, the first relay UE set after adding the user info ID of the first relay UE is {relay UE2's User Info ID, relay UE3's User Info ID}.

[0243] For another example, in conjunction with Figure 6, when the first relay UE is relay UE2 in Figure 6, the first relay UE set after adding the user info ID of the first relay UE is {User Info ID of relay UE5, User Info ID of relay UE1, User Info ID of relay UE2}. When the first relay UE is relay UE3 or relay UE4 in Figure 6, the first relay UE set after adding the user info ID of the first relay UE is {User Info ID of relay UE5, User Info ID of relay UE1, User Info ID of relay UE2, User Info ID of relay UE3 or User Info ID of relay UE4}.

[0244] If the relay forwarding identifier represents that the end UE set does not allow the relay UE to forward, it means that the discovery message only supports the one-hop relay UE discovery function. The specific processing process is related technology and will not be repeated here.

[0245] It should be noted that, when the discovery message also carries at least an RSC, the first relay UE may further determine whether the RSC is the same as the RSC configured for the first relay UE. If the RSC is different from the RSC configured for the first relay UE, the discovery message is discarded. If the RSC is the same as the RSC configured for the first relay UE, it is further determined whether the relay forwarding identifier indicates that the end UE set allows the relay UE to forward.

[0246] Step 803: Forward the discovery message with the user information identifier of the first relay UE added.

[0247] In implementation, after the first relay UE adds the user info ID of the first relay UE in the first relay UE set, the first relay UE may continue to forward the discovery message with the user information ID of the first relay UE added thereto by broadcasting.

[0248] As an optional implementation, in order to limit the scope of discovery of the relay UE, the discovery message also carries at least a hop count identifier. The hop count identifier is used to represent the number of times the end UE set allows the relay UE to forward. Accordingly, before the first relay UE adds the user information identifier of the first relay UE to the first relay UE set, it can also perform the following operations: if the hop count identifier is not 0, the hop count identifier is reduced by 1, and the step of adding the user information identifier of the first relay UE to the first relay UE set is performed; if the hop count identifier is 0, the discovery message is discarded.

[0249] In practice, to limit the scope of discovery by the relay UE, the discovery message also carries at least a hop count identifier. The first relay UE can determine whether the hop count identifier is 0. If the hop count identifier is 0, it indicates that the forwarding of the discovery message has reached the maximum hop count, and the first relay UE discards the discovery message. If the hop count identifier is not 0, the first relay UE decrements the hop count identifier by 1, adds the first relay UE's user info ID to the first relay UE set, and forwards the discovery message. In this way, by carrying the hop count in the discovery message, the scope of discovery by the relay UE is limited.

[0250] It should be noted that the relay forwarding identifier and hop count identifier can also be implemented using the relay identifier. Accordingly, the first relay UE can determine whether the value of the relay identifier is 0. If the value of the relay identifier is 0, the first relay UE discards the discovery message. If the value of the relay identifier is not 0, the first relay UE decrements the value of the relay identifier by 1, adds the user info ID of the first relay UE to the first relay UE set, and forwards the discovery message.

[0251] As an optional implementation, in order to solve the problem of discovery message flooding, the discovery message also carries at least an end UE set identifier. The end UE set identifier is used to uniquely identify the end UE set. Accordingly, before the first relay UE adds the user information identifier of the first relay UE to the first relay UE set, it can also perform the following operations: if the first relay UE has not forwarded the end UE set corresponding to the end UE set identifier, the end UE set identifier is stored locally, and the step of adding the user information identifier of the first relay UE to the first relay UE set is performed; if the first relay UE has forwarded the end UE set corresponding to the end UE set identifier, the discovery message is discarded.

[0252] In practice, during the multi-hop relay discovery process, because relay UEs can forward discovery messages via broadcast, there is a flooding problem with discovery messages. For example, with reference to Figure 4, after relay UE1, relay UE2, and relay UE3 receive a discovery request message, they can continue to forward the discovery request message to each other via broadcast, repeatedly causing serious flooding and repeated forwarding problems.

[0253] In order to solve the problem of discovery message flooding, the discovery message also carries at least an end UE set identifier. The first relay UE can determine whether it has forwarded the end UE set corresponding to the end UE set identifier. If the first relay UE has forwarded the end UE set corresponding to the end UE set identifier, it means that the discovery message is a duplicate forwarded discovery message, and the first relay UE discards the discovery message. If the first relay UE has not forwarded the end UE set corresponding to the end UE set identifier, the first relay UE stores the end UE set identifier locally, adds the user info ID of the first relay UE in the first relay UE set, and forwards the discovery message. In this way, by carrying the end UE set identifier in the discovery message, the problem of discovery message flooding is solved.

[0254] In addition, when the discovery message carries both the end UE set identifier and the hop count identifier, if the first relay UE simultaneously receives multiple discovery messages carrying the same end UE set identifier, the first relay UE forwards the discovery message with the largest hop count identifier.

[0255] As an optional implementation manner, for Mode B of the existing ProSe scenario, as shown in FIG9 , the UE further performs the following steps.

[0256] Step 901: Receive a second discovery request message sent by a relay UE. The second discovery request message carries at least one or more of the following parameters: a second end UE set, where the second end UE set includes the user information identifier of the source UE and the user information identifier of the destination UE, and the end UE is the destination UE in the second end UE set; and a second relay UE set, where the second relay UE set includes at least the user information identifiers of the relay UEs in the second end UE set that the source UE passes through to reach the destination UE.

[0257] In implementation, in conjunction with Figure 4, when the end UE is the destination UE (i.e., end UE2 in Figure 4). The end UE can receive a second discovery request message sent by the relay UE (i.e., relay UE3 in Figure 4). The second discovery request message carries at least one or more of the following parameters: a second end UE set and a second relay UE set. Among them, the second end UE set includes the user information identifier of the source end UE and the user information identifier of the destination end UE, such as {User Info ID of end UE1, User Info ID of end UE2} (since the end UE is introduced as both end UE1 and end UE2 in the embodiment of this disclosure, the second end UE set is the same as the above-mentioned first end UE); the second relay UE set includes at least the user information identifier of the relay UE in the second end UE set that the source end UE passes through to the destination end UE, such as {User Info ID of relay UE1 or User Info ID of relay UE2, User Info ID of relay UE3}. Optionally, the second discovery request message also carries at least RSC.

[0258] It should be noted that, when the discovery request message carries the end UE set identifier, after relay UE3 receives the discovery request messages forwarded by relay UE1 and relay UE2, it will only forward the discovery request message forwarded by one of the two relay UEs. Therefore, the second relay UE set in the discovery request message received by end UE2 is {Relay UE1's User Info ID or Relay UE2's User Info ID, Relay UE3's User Info ID}.

[0259] Step 902: If the destination UE in the second-end UE set includes the end UE, a discovery response message is sent to the relay UE, wherein the discovery response message carries at least the second-end UE set and the second relay UE set.

[0260] In implementation, if the destination UE in the second-end UE set includes the end UE, the end UE sends a discovery response message to the relay UE (i.e., relay UE3 in Figure 4) via unicast. The discovery response message carries at least the second-end UE set {User Info ID of end UE1, User Info ID of end UE2} and the second relay UE set {User Info ID of relay UE1 or User Info ID of relay UE2, User Info ID of relay UE3}. Optionally, the discovery response message also carries at least an RSC.

[0261] It should be noted that, when the second discovery request message also carries at least an RSC, the end UE may further determine whether the RSC is the same as the RSC configured for the end UE. If the RSC is different from the RSC configured for the end UE, the second discovery request message is discarded. If the RSC is the same as the RSC configured for the end UE, it is further determined whether the target end UE in the second end UE set includes the end UE.

[0262] As an optional implementation manner, for Mode B of the existing ProSe scenario, as shown in FIG10 , the first relay UE further performs the following steps.

[0263] Step 1001: Receive a discovery response message sent by a destination UE or a second relay UE. The discovery response message carries at least one or more of the following parameters: a source UE set; a second relay UE set, where the second relay UE set includes user information identifiers and layer 2 identifiers of relay UEs passed through by the source UE to reach the destination UE during the relay UE discovery process. The layer 2 identifier is used in the subsequent connection establishment process. The second relay UE is the relay UE following the first relay UE in the second relay UE set.

[0264] In an implementation, in conjunction with FIG4 , the first relay UE receives a discovery response message. The discovery response message may be sent by the end UE or by a second relay UE, where the second relay UE is the relay UE following the first relay UE in the second relay UE set. For example, if the first relay UE is relay UE3, the first relay UE receives the discovery response message sent by end UE2. If the first relay UE is relay UE1 or relay UE2, the first relay UE receives the discovery response message sent by relay UE3.

[0265] The discovery response message carries at least one or more of the following parameters: an end UE set, a second relay UE set, and a layer 2 identifier of the relay UE. The end UE set is {User Info ID of end UE1, User Info ID of end UE2}; the second relay UE set includes the user information identifiers of the relay UEs that the source UE passes through to reach the destination UE during the relay UE discovery process. The second relay UE set is {User Info ID of relay UE1 or User Info ID of relay UE2, User Info ID of relay UE3}; the layer 2 identifier is used in the subsequent connection establishment process. Optionally, the discovery response message also carries at least an RSC.

[0266] Step 1002: Send a discovery response message to the source UE or a third relay UE, where the third relay UE is the previous relay UE of the first relay UE in the relay UE set.

[0267] In an implementation, with reference to Figure 4 , the first relay UE sends a discovery response message to the source UE or a third relay UE via unicast, where the third relay UE is the relay UE preceding the first relay UE in the second relay UE set. For example, if the first relay UE is relay UE3, the first relay UE sends a discovery response message to relay UE1 or relay UE2. If the first relay UE is relay UE1 or relay UE2, the first relay UE sends a discovery response message to end UE1.

[0268] It should be noted that, when the discovery response message also carries at least an RSC, the first relay UE may further determine whether the RSC is the same as the RSC configured for the first relay UE. If the RSC is different from the RSC configured for the first relay UE, the discovery message is discarded. If the RSC is the same as the RSC configured for the first relay UE, a discovery response message is further sent to the source UE or the third relay UE.

[0269] FIG11 is a flowchart of Example 1 of a method for discovering a relay UE provided by an embodiment of the present disclosure. In conjunction with FIG4 , as shown in FIG11 , the specific steps are as follows:

[0270] In step 1101, UE1 broadcasts a discovery request message, which carries the UE set {UE1's User Info ID, UE2's User Info ID}, an empty relay UE set, an RSC, a relay forwarding identifier, a hop count identifier of 3, and a UE set identifier of 1-2.

[0271] In step 1102, relay UE1 forwards the discovery request message via broadcast. The discovery request message carries the end UE set {end UE1's User Info ID, end UE2's User Info ID}, the relay UE set {relay UE1's User Info ID}, the RSC, the relay forwarding identifier, the hop count identifier of 2, and the end UE set identifier 1-2.

[0272] In step 1103, relay UE2 forwards the discovery request message via broadcast. The discovery request message carries the end UE set {User Info ID of end UE1, User Info ID of end UE2}, the relay UE set {User Info ID of relay UE2}, the RSC, the relay forwarding identifier, the hop count identifier of 2, and the end UE set identifier of 1-2.

[0273] In step 1104, relay UE3 forwards the discovery request message sent by relay UE1 via broadcast. The discovery request message carries the end UE set {User Info ID of end UE1, User Info ID of end UE2}, the relay UE set {User Info ID of relay UE1, User Info ID of relay UE3}, the RSC, the relay forwarding identifier, the hop count identifier of 1, and the end UE set identifier of 1-2.

[0274] In step 1105, end UE2 sends a discovery response message to relay UE3. The discovery response message carries the end UE set {User Info ID of end UE1, User Info ID of end UE2}, the relay UE set {User Info ID of relay UE1, User Info ID of relay UE3}, and RSC.

[0275] Step 1106: Relay UE3 sends a discovery response message to relay UE1. The discovery response message carries the end UE set {User Info ID of end UE1, User Info ID of end UE2}, the relay UE set {User Info ID of relay UE1, User Info ID of relay UE3}, and RSC.

[0276] Step 1107: Relay UE1 sends a discovery response message to end UE1. The discovery response message carries the end UE set {User Info ID of end UE1, User Info ID of end UE2}, the relay UE set {User Info ID of relay UE1, User Info ID of relay UE3}, and RSC.

[0277] FIG12 is a flowchart of Example 2 of a method for discovering a relay UE provided by an embodiment of the present disclosure. In conjunction with FIG6 , as shown in FIG12 , the specific steps are as follows:

[0278] In step 1201, relay UE1 broadcasts a discovery announcement message. The discovery announcement message carries the end UE set {end UE1's User Info ID, end UE2's User Info ID}, the relay UE set {relay UE5's User Info ID, relay UE1's User Info ID}, the RSC, the relay forwarding identifier, a hop count identifier of 3, and the end UE set identifier 1-2.

[0279] In step 1202, relay UE2 forwards the discovery announcement message via broadcast. The discovery announcement message carries the end UE set {end UE1's User Info ID, end UE2's User Info ID}, the relay UE set {relay UE5's User Info ID, relay UE1's User Info ID, relay UE2's User Info ID}, the RSC, the relay forwarding identifier, the hop count identifier of 2, and the end UE set identifier of 1-2.

[0280] In step 1203, relay UE3 and relay UE4 forward the discovery announcement message via broadcast. The discovery announcement message carries the end UE set {end UE1's User Info ID, end UE2's User Info ID}, the relay UE set {relay UE5's User Info ID, relay UE1's User Info ID, relay UE2's User Info ID, and either relay UE3 or relay UE4's User Info ID}, the RSC, a relay forwarding identifier, a hop count identifier of 1, and an end UE set identifier of 1-2.

[0281] As an optional implementation, for Mode B of the existing ProSe scenario, as shown in Figure 13, the end UE can also obtain parameters related to the relay UE discovery process from the PCF network element through the AMF (Access and Mobility Management Function) network element. The specific processing steps are as follows:

[0282] Step 1301: Send a registration request message to the AMF network element. The registration request message carries at least a proximity service capability parameter, which includes a first-end UE set and / or a multi-hop relay identifier. The multi-hop relay identifier is used to indicate that the first-end UE supports the multi-hop relay UE discovery function.

[0283] In implementation, the end UE may send a Registration Request message to the AMF network element. The Registration Request message may carry at least a ProSe capability parameter. The ProSe capability parameter may include a first end UE set and / or a multi-hop relay identifier. The multi-hop relay identifier may be used to indicate that the end UE supports the discovery function of a multi-hop relay UE (End UE with multi-hop support).

[0284] Step 1302: Receive a NAS message sent by the PCF network element through the AMF network element. The NAS message carries at least proximity service policy parameters, which include at least the user information identifier of the end UE, the first RSC, the end UE set identifier, and / or the hop count identifier.

[0285] In implementation, the end UE receives a NAS (Non-Access Stratum) message sent by the PCF network element through the AMF network element. The NAS message carries at least ProSe Policy parameters. The ProSe Policy parameters include the user info ID of the end UE, the first RSC, the end UE set identifier, and / or the hop count identifier. Optionally, after receiving the ProSe Policy parameters sent by the AMF network element, the end UE may send a NAS message carrying the ProSe Policy delivery result to the AMF network element.

[0286] As an optional implementation, for Mode A of the existing ProSe scenario, as shown in Figure 14, the first relay UE can also obtain parameters related to the relay UE discovery process from the PCF network element through the AMF network element. The specific processing steps are as follows:

[0287] Step 1401: Send a registration request message to the AMF network element. The registration request message carries at least a proximity service capability parameter, which includes a set of end UEs and / or a multi-hop relay identifier. The multi-hop relay identifier is used to indicate that the first relay UE supports the discovery function of the multi-hop relay UE.

[0288] In implementation, the first relay UE sends a registration request message to the AMF network element. The registration request message carries at least a proximity service capability parameter. The proximity service capability parameter includes a set of end UEs and / or a multi-hop relay identifier. The multi-hop relay identifier is used to indicate that the first relay UE supports the discovery function of multi-hop relay UEs (UE-to-UE Relay with multi-hop support).

[0289] Step 1402: Receive a NAS message sent by the PCF network element through the AMF network element. The NAS message carries at least proximity service policy parameters, which include a user information identifier of the first relay UE, a terminal UE set identifier, and / or a hop count identifier.

[0290] During implementation, the first relay UE receives a NAS message sent by the PCF network element through the AMF network element. The NAS message carries at least proximity service policy parameters. The proximity service policy parameters include the first relay UE's user info ID, the end UE set identifier, and / or the initial hop count. Optionally, the proximity service policy parameters also include at least the RSC. Optionally, after receiving the proximity service policy parameters sent by the AMF network element, the first relay UE may send a NAS message carrying the proximity service policy delivery result to the AMF network element.

[0291] As an optional implementation, for Mode A and Mode B of the existing ProSe scenario, as shown in Figure 15, the processing process of the AMF network element is as follows:

[0292] Step 1501: Receive a registration request message sent by a UE. The registration request message carries at least a proximity service capability parameter, which includes a set of end UEs and / or a multi-hop relay identifier. The multi-hop relay identifier is used to indicate that the UE supports a multi-hop relay UE discovery function.

[0293] In implementation, the AMF network element receives a registration request message sent by a UE (including an end UE and a relay UE). The registration request message carries at least a proximity service capability parameter. The proximity service capability parameter includes an end UE set and / or a multi-hop relay identifier. The multi-hop relay identifier is used to indicate that the UE supports the discovery function of a multi-hop relay UE. Optionally, after receiving the registration request message sent by the UE, the AMF network element may send a registration accept message to the UE.

[0294] Step 1502: Send a first NAS message to the PCF network element, wherein the first NAS message carries at least a proximity service capability parameter.

[0295] In implementation, the AMF network element sends a first NAS message (such as Npcf_UEPolicyControl Create Request) to the PCF network element, wherein the first NAS message carries at least a proximity service capability parameter.

[0296] Step 1503: Receive a second NAS message sent by the PCF network element; wherein the second NAS message carries at least proximity service policy parameters, and the proximity service policy parameters include a UE user information identifier, a terminal UE set identifier, and / or a hop count identifier.

[0297] During implementation, the AMF network element receives a second NAS message (e.g., Namf_Communication_N1N2MessageTransfer) sent by the PCF network element. The second NAS message carries at least proximity service policy parameters. The proximity service policy parameters include the UE's user info ID, the end UE set identifier, and / or the hop count. Optionally, the proximity service policy parameters also include at least the RSC.

[0298] Step 1504: Send a third NAS message to the UE, wherein the third NAS message carries proximity service policy parameters.

[0299] During implementation, the AMF network element sends a third NAS message to the UE. The third NAS message carries at least the proximity service policy parameters. Optionally, after receiving the proximity service policy parameters sent by the AMF network element, the UE may send a NAS message carrying the proximity service policy delivery result to the AMF network element. Correspondingly, the AMF network element may send a NAS message (such as Namf_N1MessageNotify) carrying the proximity service policy delivery result to the PCF network element.

[0300] As an optional implementation, for Mode A and Mode B of the existing ProSe scenario, as shown in FIG16 , the processing process of the PCF network element is as follows:

[0301] Step 1601: Receive a first NAS message sent by an AMF network element. The first NAS message carries at least a proximity service capability parameter, which includes a set of end UEs and / or a multi-hop relay identifier. The multi-hop relay identifier is used to indicate that the UE supports the multi-hop relay UE discovery function.

[0302] During implementation, the PCF network element receives a first NAS message (e.g., Npcf_UEPolicyControl Create Request) sent by the AMF network element. The first NAS message carries at least a proximity service capability parameter, which includes a terminal UE set and / or a multi-hop relay identifier. The multi-hop relay identifier is used to indicate that the UE supports the discovery function of a multi-hop relay UE. Optionally, after the PCF network element receives the first NAS message sent by the AMF network element, the PCF network element may send a NAS message (e.g., Npcf_UEPolicyControl Create Response) to the AMF network element.

[0303] Step 1602: Send a second NAS message to the AMF network element. The second NAS message carries at least proximity service policy parameters, which include a UE user information identifier, a terminal UE set identifier, and / or a hop count identifier. The terminal UE set identifier is generated based on the terminal UE set.

[0304] In implementation, the PCF network element may generate an end UE set identifier based on the end UE set and determine the UE's user info ID and hop count identifier. Then, the PCF network element sends a second NAS message (such as Namf_Communication_N1N2MessageTransfer) to the AMF network element. The second NAS message carries at least proximity service policy parameters, which include at least the UE's user info ID, the end UE set identifier, and the hop count identifier. The proximity service policy parameters may be included in a user equipment policy container (UE Policy Container). Optionally, the proximity service policy parameters also carry at least an RSC.

[0305] FIG17 is a flowchart of Example 3 of a method for discovering a relay UE provided by an embodiment of the present disclosure. As shown in FIG17 , the specific steps are as follows:

[0306] In step 1701, the UE sends a registration request message to the AMF network element. The registration request message carries at least a proximity service capability parameter, which includes a set of end UEs and / or a multi-hop relay identifier. The multi-hop relay identifier is used to indicate that the UE supports the discovery function of multi-hop relay UEs.

[0307] Step 1702: The AMF network element sends a registration acceptance message to the UE.

[0308] In step 1703, the AMF network element sends an Npcf_UEPolicyControl Create Request to the PCF network element, wherein the Npcf_UEPolicyControl Create Request carries the proximity service capability parameter.

[0309] Step 1704: The PCF network element sends Npcf_UEPolicyControl Create Response to the AMF network element.

[0310] In step 1705, the PCF network element sends a Namf_Communication_N1N2MessageTransfer message to the AMF network element. The Namf_Communication_N1N2MessageTransfer message carries at least the proximity service policy parameters, which include at least the UE's user information identifier, RSC, end UE set identifier, and hop count identifier.

[0311] Step 1706: The AMF network element sends a NAS message to the UE, wherein the NAS message carries proximity service policy parameters.

[0312] Step 1707: The UE sends a NAS message to the AMF network element, where the NSA message carries the proximity service policy delivery result.

[0313] In step 1708, the AMF network element sends a Namf_N1MessageNotify message to the PCF network element, wherein the Namf_N1MessageNotify message carries the result of the proximity service policy delivery.

[0314] The embodiments of the present disclosure provide a method for discovering a relay UE, which can implement a multi-hop relay UE discovery process of the Model B mode initiated by an end UE and a multi-hop relay UE discovery process of the Model A mode initiated by a relay UE.

[0315] It can be understood that the same / similar parts between the various embodiments of the above method in this specification can be referred to each other, and each embodiment focuses on the differences from other embodiments. For related parts, please refer to the description of other method embodiments.

[0316] The present disclosure also provides a relay UE, as shown in FIG18 , including a memory 1810, a transceiver 1820, and a processor 1830, wherein the memory 1810 is configured to store a computer program; the transceiver 1820 is configured to transmit and receive data under the control of the processor 1830; and the processor 1830 is configured to read the computer program in the memory 1810 and perform the following operations:

[0317] Receive discovery messages;

[0318] If the relay forwarding identifier represents that the end UE set allows the relay UE to forward, then the user information identifier of the first relay UE is added to the first relay UE set;

[0319] Forwarding the discovery message with the user information identifier of the first relay UE added;

[0320] The discovery message carries at least one or more of the following parameters:

[0321] End UE set, where the end UE set includes the user information identifier of the source UE and the user information identifier of the destination UE;

[0322] A first relay UE set, where the first relay UE set includes user information identifiers of relay UEs passed through by the source UE to reach the first relay UE during the relay UE discovery process;

[0323] The relay forwarding identifier is used to indicate whether the end UE set allows the relay UE to forward.

[0324] As an optional implementation manner, receiving a discovery message includes:

[0325] Receive discovery announcement messages sent by other relay UEs;

[0326] Alternatively, a discovery request message sent by a source UE or other relay UE is received.

[0327] As an optional implementation manner, the discovery message further carries at least a hop count identifier, and the hop count identifier is used to represent the number of times the end UE set allows the relay UE to forward the message.

[0328] As an optional implementation manner, before adding the user information identifier of the first relay UE to the first relay UE set, the processor 1830 is further configured to perform the following operations:

[0329] If the hop count identifier is not 0, decrement the hop count identifier by 1 and add the user information identifier of the first relay UE to the first relay UE set;

[0330] If the hop count indicator is 0, the discovery message is discarded.

[0331] As an optional implementation manner, the discovery message further carries at least an end UE set identifier, and the end UE set identifier is used to uniquely identify the end UE set.

[0332] As an optional implementation manner, before adding the user information identifier of the first relay UE to the first relay UE set, the processor 1830 is further configured to perform the following operations:

[0333] If the first relay UE has not forwarded the end UE set identifier, the end UE set identifier is stored locally, and the user information identifier of the first relay UE is added to the first relay UE set;

[0334] If the first relay UE has forwarded the end UE set identifier, the discovery message is discarded.

[0335] As an optional implementation manner, the processor 1830 is further configured to perform the following operations:

[0336] Receiving a discovery response message sent by the destination UE or the second relay UE;

[0337] Sending a discovery response message to the source UE or the third relay UE;

[0338] The discovery response message carries at least one or more of the following parameters:

[0339] End UE set;

[0340] The second relay UE set includes the user information identifier of the relay UE passed by the source UE to reach the destination UE during the relay UE discovery process and the layer 2 identifier of the relay UE. The layer 2 identifier is used for the subsequent connection establishment process. The second relay UE is the relay UE after the first relay UE in the second relay UE set, and the third relay UE is the relay UE before the first relay UE in the relay UE set.

[0341] As an optional implementation manner, the processor 1830 is further configured to perform the following operations:

[0342] Send a discovery announcement message; the discovery announcement message carries at least one or more of the following parameters:

[0343] An end UE set, where the end UE set is an end UE set obtained by the first relay UE during a relay UE discovery process and / or a UE communication process;

[0344] a third relay UE set, where the third relay UE set at least includes user information identifiers of relay UEs passed by the source end UE in the end UE set to reach the first relay UE;

[0345] The relay forwarding identifier is used to indicate whether the end UE set allows the relay UE to forward.

[0346] As an optional implementation method, it is discovered that the announcement message also carries at least a hop count identifier, which is used to represent the number of times the end UE set allows the relay UE to forward. The hop count identifier is determined based on the initial hop count identifier and the number of hops corresponding to the source end UE in the end UE set reaching the first relay UE. The initial hop count identifier is determined by the first relay UE or the policy control function PCF network element.

[0347] As an optional implementation, it is discovered that the announcement message also carries at least an end UE set identifier, which is used to uniquely identify the end UE set. The end UE set identifier is generated by the first relay UE or PCF network element based on the end UE set.

[0348] As an optional implementation manner, the processor 1830 is further configured to perform the following operations:

[0349] Send a registration request message to the access and mobility management function AMF network element; wherein the registration request message carries at least a proximity service capability parameter, the proximity service capability parameter includes an end UE set and / or a multi-hop relay identifier, and the multi-hop relay identifier is used to indicate that the first relay UE supports the discovery function of the multi-hop relay UE;

[0350] The non-access layer NAS message sent by the PCF network element is received through the AMF network element; wherein the NAS message carries at least a proximity service policy parameter, and the proximity service policy parameter includes the user information identifier, RSC, end UE set identifier and / or hop count identifier of the first relay UE.

[0351] The present disclosure also provides a terminal UE, as shown in FIG19 , including a memory 1910, a transceiver 1920, and a processor 1930. The memory 1910 is configured to store a computer program; the transceiver 1920 is configured to transmit and receive data under the control of the processor 1930; and the processor 1930 is configured to read the computer program in the memory 1910 and perform the following operations:

[0352] Send a first discovery request message; wherein the first discovery request message carries at least one or more of the following parameters:

[0353] A first-end UE set, where the first-end UE set includes a user information identifier of a source-end UE and a user information identifier of a destination-end UE, and the destination-end UE is a source-end UE in the first-end UE set;

[0354] a first relay UE set;

[0355] The relay forwarding identifier is used to indicate whether the first-end UE set allows the relay UE to forward.

[0356] As an optional implementation manner, the processor 1930 is further configured to perform the following operations:

[0357] receiving a second discovery request message sent by the relay UE;

[0358] If the destination UE in the second-end UE set includes the end UE, sending a discovery response message to the relay UE;

[0359] The second discovery request message carries at least one or more of the following parameters:

[0360] A second-end UE set, where the second-end UE set includes a user information identifier of a source UE and a user information identifier of a destination UE, and the source UE is a destination UE in the second-end UE set;

[0361] A second relay UE set, where the second relay UE set includes at least user information identifiers of relay UEs passed through by the source UE to the destination UE in the second end UE set;

[0362] The discovery response message carries at least one or more of the following parameters:

[0363] A second-end UE set;

[0364] The second relay UE set.

[0365] As an optional implementation, the first discovery request message also carries at least a hop count identifier, which is used to represent the number of times the first-end UE set allows the relay UE to forward, and the hop count identifier is determined by the end UE or the policy control function PCF network element.

[0366] As an optional implementation, the first discovery request message also carries at least an end UE set identifier, which is used to uniquely identify the first end UE set. The end UE set identifier is generated by the end UE or PCF network element based on the first end UE set.

[0367] As an optional implementation manner, the processor 1930 is further configured to perform the following operations:

[0368] Send a registration request message to the access and mobility management function AMF network element; wherein the registration request message carries at least a proximity service capability parameter, the proximity service capability parameter includes the first-end UE set and / or the multi-hop relay identifier, and the multi-hop relay identifier is used to indicate that the end UE supports the discovery function of the multi-hop relay UE;

[0369] The non-access layer NAS message sent by the PCF network element is received through the AMF network element; wherein the NAS message carries at least a proximity service policy parameter, and the proximity service policy parameter includes at least the user information identifier of the end UE, the first RSC, the end UE set identifier and / or the hop count identifier.

[0370] The present disclosure also provides an AMF network element, as shown in FIG20 , including a memory 2010, a transceiver 2020, and a processor 2030, wherein the memory 2010 is used to store a computer program; the transceiver 2020 is used to send and receive data under the control of the processor 2030; and the processor 2030 is used to read the computer program in the memory 2010 and perform the following operations:

[0371] Receive a registration request message sent by the UE;

[0372] Sending a first non-access stratum (NAS) message to a policy control function (PCF) network element;

[0373] Receive a second NAS message sent by the PCF network element;

[0374] Sending a third NAS message to the UE;

[0375] The registration request message carries at least a proximity service capability parameter, which includes a terminal UE set and / or a multi-hop relay identifier, and the multi-hop relay identifier is used to indicate that the UE supports the discovery function of the multi-hop relay UE;

[0376] The first NAS message carries at least a proximity service capability parameter;

[0377] The second NAS message carries at least proximity service policy parameters, where the proximity service policy parameters include a UE user information identifier, a relay service code RSC, an end UE set identifier, and / or a hop count identifier;

[0378] The third NAS message carries proximity service policy parameters.

[0379] The present disclosure also provides a PCF network element, as shown in FIG21 , including a memory 2110, a transceiver 2120, and a processor 2130. The memory 2110 is configured to store a computer program; the transceiver 2120 is configured to transmit and receive data under the control of the processor 2130; and the processor 2130 is configured to read the computer program in the memory 2110 and perform the following operations:

[0380] Receive the first non-access stratum NAS message sent by the access and mobility management function AMF network element;

[0381] Send a second NAS message to the AMF network element;

[0382] The first NAS message carries at least a proximity service capability parameter, the proximity service capability parameter includes an end UE set and / or a multi-hop relay identifier, and the multi-hop relay identifier is used to indicate that the UE supports a discovery function of a multi-hop relay UE;

[0383] The second NAS message carries at least proximity service policy parameters, which include a UE user information identifier, a relay service code RSC, an end UE set identifier, and / or a hop count identifier. The end UE set identifier is generated based on the end UE set.

[0384] The present disclosure also provides a discovery device for a relay UE, as shown in FIG22 . The device is applied to a first relay UE and includes:

[0385] The first receiving unit 2210 is configured to receive a discovery message;

[0386] An adding unit 2220 is configured to add a user information identifier of the first relay UE to the first relay UE set if the relay forwarding identifier represents that the end UE set allows the relay UE to forward;

[0387] The first sending unit 2230 is configured to forward the discovery message with the user information identifier of the first relay UE added;

[0388] The discovery message carries at least one or more of the following parameters:

[0389] End UE set, where the end UE set includes the user information identifier of the source UE and the user information identifier of the destination UE;

[0390] A first relay UE set, where the first relay UE set includes user information identifiers of relay UEs passed through by the source UE to reach the first relay UE during the relay UE discovery process;

[0391] The relay forwarding identifier is used to indicate whether the end UE set allows the relay UE to forward.

[0392] As an optional implementation manner, the first receiving unit 2210 is specifically configured to:

[0393] Receive discovery announcement messages sent by other relay UEs;

[0394] Alternatively, a discovery request message sent by a source UE or other relay UE is received.

[0395] As an optional implementation manner, the discovery message further carries at least a hop count identifier, and the hop count identifier is used to represent the number of times the end UE set allows the relay UE to forward the message.

[0396] As an optional embodiment, the device further includes:

[0397] a first determining unit, configured to, if the hop count identifier is not 0, decrement the hop count identifier by 1 and add the user information identifier of the first relay UE to the first relay UE set;

[0398] The first discarding unit is configured to discard the discovery message if the hop count identifier is 0.

[0399] As an optional implementation manner, the discovery message further carries at least an end UE set identifier, and the end UE set identifier is used to uniquely identify the end UE set.

[0400] As an optional embodiment, the device further includes:

[0401] A second determining unit is configured to store the end UE set identifier locally and add the user information identifier of the first relay UE to the first relay UE set if the first relay UE has not forwarded the end UE set identifier;

[0402] The second discarding unit is configured to discard the discovery message if the first relay UE has forwarded the end UE set identifier.

[0403] As an optional embodiment, the device further includes:

[0404] A second receiving unit, configured to receive a discovery response message sent by the destination UE or the second relay UE;

[0405] A second sending unit, configured to send a discovery response message to the source UE or the third relay UE;

[0406] The discovery response message carries at least one or more of the following parameters:

[0407] End UE set;

[0408] The second relay UE set includes the user information identifier of the relay UE passed by the source UE to reach the destination UE during the relay UE discovery process and the layer 2 identifier of the relay UE. The layer 2 identifier is used for the subsequent connection establishment process. The second relay UE is the relay UE after the first relay UE in the second relay UE set, and the third relay UE is the relay UE before the first relay UE in the relay UE set.

[0409] As an optional embodiment, the device further includes:

[0410] The third sending unit is configured to send a discovery announcement message, wherein the discovery announcement message carries at least one or more of the following parameters:

[0411] An end UE set, where the end UE set is an end UE set obtained by the first relay UE during a relay UE discovery process and / or a UE communication process;

[0412] a third relay UE set, where the third relay UE set at least includes user information identifiers of relay UEs passed by the source end UE in the end UE set to reach the first relay UE;

[0413] The relay forwarding identifier is used to indicate whether the end UE set allows the relay UE to forward.

[0414] As an optional implementation method, it is discovered that the announcement message also carries at least a hop count identifier, which is used to represent the number of times the end UE set allows the relay UE to forward. The hop count identifier is determined based on the initial hop count identifier and the number of hops corresponding to the source end UE in the end UE set reaching the first relay UE. The initial hop count identifier is determined by the first relay UE or the policy control function PCF network element.

[0415] As an optional implementation, it is discovered that the announcement message also carries at least an end UE set identifier, which is used to uniquely identify the end UE set. The end UE set identifier is generated by the first relay UE or PCF network element based on the end UE set.

[0416] As an optional embodiment, the device further includes:

[0417] The fourth sending unit sends a registration request message to the access and mobility management function AMF network element; wherein the registration request message carries at least a proximity service capability parameter, the proximity service capability parameter includes an end UE set and / or a multi-hop relay identifier, and the multi-hop relay identifier is used to indicate that the first relay UE supports a discovery function of a multi-hop relay UE;

[0418] The third receiving unit is used to receive a non-access layer NAS message sent by the PCF network element through the AMF network element; wherein the NAS message carries at least a proximity service policy parameter, and the proximity service policy parameter includes a user information identifier of the first relay UE, an end UE set identifier and / or a hop count identifier.

[0419] The present disclosure also provides a discovery device for a relay UE, as shown in FIG23 . The device is applied to an end UE and includes:

[0420] The first sending unit 2310 is configured to send a first discovery request message, wherein the first discovery request message carries at least one or more of the following parameters:

[0421] A first-end UE set, where the first-end UE set includes a user information identifier of a source-end UE and a user information identifier of a destination-end UE, and the destination-end UE is a source-end UE in the first-end UE set;

[0422] a first relay UE set;

[0423] The relay forwarding identifier is used to indicate whether the first-end UE set allows the relay UE to forward.

[0424] As an optional embodiment, the device further includes:

[0425] A first receiving unit, configured to receive a second discovery request message sent by the relay UE;

[0426] A second sending unit is configured to send a discovery response message to the relay UE if the destination end UE in the second end UE set includes the end UE;

[0427] The second discovery request message carries at least one or more of the following parameters:

[0428] A second-end UE set, where the second-end UE set includes a user information identifier of a source UE and a user information identifier of a destination UE, and the source UE is a destination UE in the second-end UE set;

[0429] A second relay UE set, where the second relay UE set includes at least user information identifiers of relay UEs passed through by the source UE to the destination UE in the second end UE set;

[0430] The discovery response message carries at least one or more of the following parameters:

[0431] A second-end UE set;

[0432] The second relay UE set.

[0433] As an optional implementation, the first discovery request message also carries at least a hop count identifier, which is used to represent the number of times the first-end UE set allows the relay UE to forward, and the hop count identifier is determined by the end UE or the policy control function PCF network element.

[0434] As an optional implementation, the first discovery request message also carries at least an end UE set identifier, which is used to uniquely identify the first end UE set. The end UE set identifier is generated by the end UE or PCF network element based on the first end UE set.

[0435] As an optional embodiment, the device further includes:

[0436] The third sending unit is configured to send a registration request message to the access and mobility management function AMF network element; wherein the registration request message carries at least a proximity service capability parameter, the proximity service capability parameter includes a first-end UE set and / or a multi-hop relay identifier, and the multi-hop relay identifier is used to indicate that the end UE supports a discovery function of a multi-hop relay UE;

[0437] The second receiving unit is used to receive a non-access layer NAS message sent by the PCF network element through the AMF network element; wherein the NAS message carries at least a proximity service policy parameter, and the proximity service policy parameter includes at least a user information identifier of the end UE, an end UE set identifier and / or a hop count identifier.

[0438] The present disclosure also provides a discovery device for a relay UE, as shown in FIG24 . The device is applied to an AMF network element and includes:

[0439] The first receiving unit 2410 is configured to receive a registration request message sent by a UE;

[0440] The first sending unit 2420 is configured to send a first non-access stratum (NAS) message to a policy control function (PCF) network element;

[0441] The second receiving unit 2430 is configured to receive a second NAS message sent by the PCF network element;

[0442] The second sending unit 2440 is configured to send a third NAS message to the UE;

[0443] The registration request message carries at least a proximity service capability parameter, which includes a terminal UE set and / or a multi-hop relay identifier, and the multi-hop relay identifier is used to indicate that the UE supports the discovery function of the multi-hop relay UE;

[0444] The first NAS message carries at least a proximity service capability parameter;

[0445] The second NAS message carries at least a proximity service policy parameter, where the proximity service policy parameter includes a UE user information identifier, a terminal UE set identifier, and / or a hop count identifier;

[0446] The third NAS message carries proximity service policy parameters.

[0447] The present disclosure also provides a device for discovering a relay UE, as shown in FIG25 . The device is applied to a PCF network element and includes:

[0448] The receiving unit 2510 is configured to receive a first non-access stratum NAS message sent by an access and mobility management function AMF network element;

[0449] The sending unit 2520 is configured to send a second NAS message to the AMF network element;

[0450] The first NAS message carries at least a proximity service capability parameter, the proximity service capability parameter includes an end UE set and / or a multi-hop relay identifier, and the multi-hop relay identifier is used to indicate that the UE supports a discovery function of a multi-hop relay UE;

[0451] The second NAS message carries at least proximity service policy parameters, which include a UE user information identifier, an end UE set identifier, and / or a hop count identifier. The end UE set identifier is generated based on the end UE set.

[0452] It should be noted that the division of units in the embodiments of the present disclosure is schematic and is merely a logical functional division. In actual implementation, other division methods may be used. Furthermore, the functional units in the various embodiments of the present disclosure may be integrated into a single processing unit, or each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0453] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a processor-readable storage medium. Based on this understanding, the technical solution of the present disclosure, or the part that contributes to the relevant technology, or all or part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a number of instructions for causing a computer device (which can be a personal computer, server, or network device, etc.) or a processor to execute all or part of the steps of the method described in each embodiment of the present disclosure.

[0454] It should be noted here that the above-mentioned device provided in the embodiment of the present disclosure can implement all the method steps implemented in the above-mentioned method embodiment and can achieve the same technical effect. The parts and beneficial effects of this embodiment that are the same as those in the method embodiment will not be described in detail here.

[0455] An embodiment of the present disclosure provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the steps of the above-mentioned method for discovering a relay UE are implemented.

[0456] An embodiment of the present disclosure provides a communication system, which includes a relay UE, an end UE, an AMF network element and a PCF network element. The relay UE executes the steps of the method implemented by the above-mentioned first relay UE, the end UE executes the steps of the method implemented by the above-mentioned end UE, the AMF network element executes the steps of the method implemented by the above-mentioned AMF network element, and the PCF network element executes the steps of the method implemented by the above-mentioned PCF network element.

[0457] The processor-readable storage medium can be any available medium or data storage device that can be accessed by the processor, including but not limited to magnetic storage (such as floppy disks, hard disks, magnetic tapes, magneto-optical disks (MO)), optical storage (such as CDs, DVDs, BDs, HVDs, etc.), and semiconductor storage (such as ROMs, EPROMs, EEPROMs, non-volatile memories (NAND FLASH), solid-state drives (SSDs)), etc.

[0458] Those skilled in the art will appreciate that the embodiments of the present disclosure may be provided as methods, systems, or computer program products. Therefore, the present disclosure may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present disclosure may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage and optical storage, etc.) containing computer-usable program code.

[0459] The present disclosure is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present disclosure. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer-executable instructions. These computer-executable instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device produce a device for implementing the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0460] These processor-executable instructions may also be stored in a processor-readable memory that can direct a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the processor-readable memory produce a product including an instruction device that implements the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0461] Obviously, those skilled in the art may make various changes and modifications to the present disclosure without departing from the spirit and scope of the present disclosure. Thus, if these modifications and variations of the present disclosure fall within the scope of the claims of the present disclosure and their equivalents, the present disclosure is intended to include these modifications and variations.

Claims

1. A method for discovering a relay user equipment (UE), wherein, The method is applied to a first relay UE, and the method includes: Receiving a discovery message; If the relay forwarding identifier indicates that the set of end UEs allows the relay UE to forward, adding the user information identifier of the first relay UE to the first relay UE set; Forwarding the discovery message after adding the user information identifier of the first relay UE; Wherein, the discovery message carries at least one or more of the following parameters: The set of end UEs, which includes the user information identifiers of the source end UE and the destination end UE; The first relay UE set, which includes the user information identifiers of the relay UEs passed by from the source end UE to the first relay UE during the relay UE discovery process; The relay forwarding identifier, which is used to indicate whether the set of end UEs allows the relay UE to forward.

2. The method according to claim 1, wherein The receiving the discovery message includes: Receiving a discovery announcement message sent by another relay UE; Or, receiving a discovery request message sent by the source end UE or another relay UE.

3. The method according to claim 1 or 2, wherein, The discovery message also carries at least a hop count identifier, which is used to indicate the number of times the set of end UEs allows the relay UE to forward.

4. The method according to claim 3, wherein, Before adding the user information identifier of the first relay UE to the first relay UE set, the method further includes: If the hop count identifier is not 0, decrementing the hop count identifier by 1 and adding the user information identifier of the first relay UE to the first relay UE set; If the hop count identifier is 0, discarding the discovery message.

5. The method according to claim 1 or 2, wherein The discovery message also carries at least an end UE set identifier, which is used to uniquely identify the set of end UEs.

6. The method according to claim 5, wherein, Before adding the user information identifier of the first relay UE to the first relay UE set, the method further includes: If the first relay UE has not forwarded the end UE set identifier, storing the end UE set identifier locally and adding the user information identifier of the first relay UE to the first relay UE set; If the first relay UE has already forwarded the end UE set identifier, discarding the discovery message.

7. The method according to claim 1, wherein The method further includes: Receiving a discovery response message sent by the destination end UE or a second relay UE; Sending the discovery response message to the source end UE or a third relay UE; Wherein, the discovery response message carries at least one or more of the following parameters: The set of end UEs; A second relay UE set, which includes the user information identifiers of the relay UEs passed by from the source end UE to the destination end UE during the relay UE discovery process and the layer 2 identifier of the relay UE, and the layer 2 identifier is used for the subsequent connection establishment process. The second relay UE is the relay UE after the first relay UE in the second relay UE set, and the third relay UE is the relay UE before the first relay UE in the relay UE set.

8. The method according to claim 1, wherein The method further includes: Sending a discovery announcement message; wherein, the discovery announcement message carries at least one or more of the following parameters: The set of end UEs, which is the set of end UEs obtained by the first relay UE during the relay UE discovery process and / or the UE communication process; The third relay UE set, which at least includes the user information identifiers of the relay UEs through which the source end UE in the set of end UEs reaches the first relay UE; The relay forwarding identifier, which is used to indicate whether the set of end UEs allows the relay UE to perform forwarding.

9. The method according to claim 8, wherein The discovery announcement message also at least carries a hop count identifier, which is used to indicate the number of times the set of end UEs allows the relay UE to forward. The hop count identifier is determined according to the initial hop count identifier and the hop count corresponding to the source end UE in the set of end UEs reaching the first relay UE. The initial hop count identifier is determined by the first relay UE or the policy control function PCF network element.

10. The method according to claim 8, wherein, The discovery announcement message also at least carries a set of end UE identifiers, which is used to uniquely identify the set of end UEs. The set of end UE identifiers is generated by the first relay UE or the PCF network element according to the set of end UEs.

11. The method according to claim 8, wherein, The method further includes: Sending a registration request message to the access and mobility management function AMF network element; wherein, the registration request message at least carries a proximity service capability parameter, and the proximity service capability parameter includes the set of end UEs and / or the multi-hop relay identifier, and the multi-hop relay identifier is used to indicate that the first relay UE supports the discovery function of the multi-hop relay UE; Receiving a non-access stratum NAS message sent by the PCF network element through the AMF network element; wherein, the NAS message at least carries a proximity service policy parameter, and the proximity service policy parameter includes the user information identifier of the first relay UE, the set of end UE identifiers, and / or the hop count identifier.

12. A method for discovering a relay user equipment (UE), wherein, The method is applied to an end UE, and the method includes: Sending a first discovery request message; wherein, the first discovery request message at least carries one or more of the following parameters: The first set of end UEs, which includes the user information identifier of the source end UE and the user information identifier of the destination end UE, and the end UE is the source end UE in the first set of end UEs; The first relay UE set; The relay forwarding identifier, which is used to indicate whether the first set of end UEs allows the relay UE to perform forwarding.

13. The method according to claim 12, wherein, The method further includes: Receiving a second discovery request message sent by the relay UE; If the destination end UE in the second set of end UEs includes the end UE, sending a discovery response message to the relay UE; Wherein, the second discovery request message at least carries one or more of the following parameters: The second set of end UEs, which includes the user information identifier of the source end UE and the user information identifier of the destination end UE, and the end UE is the destination end UE in the second set of end UEs; The second relay UE set, which at least includes the user information identifiers of the relay UEs through which the source end UE in the second set of end UEs reaches the destination end UE; The discovery response message carries at least one or more of the following parameters; The second set of UE; The second set of relay UE.

14. The method according to claim 12, wherein The first discovery request message further carries at least a hop count identifier, where the hop count identifier is used to characterize the number of times the first set of UE allows the relay UE to forward, and the hop count identifier is determined by the UE or the Policy Control Function (PCF) network element.

15. The method according to claim 12, wherein The first discovery request message further carries at least a set of UE identifier, where the set of UE identifier is used to uniquely identify the first set of UE, and the set of UE identifier is generated by the UE or the PCF network element according to the first set of UE.

16. The method according to claim 14 or 15, wherein The method further includes: Sending a registration request message to the Access and Mobility Management Function (AMF) network element; wherein, the registration request message carries at least a proximity service capability parameter, and the proximity service capability parameter includes the first set of UE and / or a multi-hop relay identifier, and the multi-hop relay identifier is used to characterize that the UE supports the discovery function of the multi-hop relay UE; Receiving a non-access stratum (NAS) message sent by the PCF network element through the AMF network element; wherein, the NAS message carries at least a proximity service policy parameter, and the proximity service policy parameter at least includes a user information identifier of the UE, a set of UE identifier, and / or a hop count identifier.

17. A method for discovering a relay user equipment (UE), wherein, The method is applied to the Access and Mobility Management Function (AMF) network element, and the method includes: Receiving a registration request message sent by the UE; Sending a first NAS message to the Policy Control Function (PCF) network element; Receiving a second NAS message sent by the PCF network element; Sending a third NAS message to the UE; Wherein, the registration request message carries at least a proximity service capability parameter, and the proximity service capability parameter includes a set of UE and / or a multi-hop relay identifier, and the multi-hop relay identifier is used to characterize that the UE supports the discovery function of the multi-hop relay UE; The first NAS message carries at least the proximity service capability parameter; The second NAS message carries at least a proximity service policy parameter, and the proximity service policy parameter includes a user information identifier of the UE, a set of UE identifier, and / or a hop count identifier; The third NAS message carries the proximity service policy parameter.

18. A discovery method for a relay user equipment (UE), wherein, The method is applied to the Policy Control Function (PCF) network element, and the method includes: Receiving a first NAS message sent by the Access and Mobility Management Function (AMF) network element; Sending a second NAS message to the AMF network element; Wherein, the first NAS message carries at least a proximity service capability parameter, and the proximity service capability parameter includes a set of UE and / or a multi-hop relay identifier, and the multi-hop relay identifier is used to characterize that the UE supports the discovery function of the multi-hop relay UE; The second NAS message carries at least a proximity service policy parameter, and the proximity service policy parameter includes a user information identifier of the UE, a set of UE identifier, and / or a hop count identifier, and the set of UE identifier is generated based on the set of UE.

19. A relay user equipment (UE), wherein, It includes a memory, a transceiver, and a processor. Among them, the memory is used to store computer programs; the transceiver is used to send and receive data under the control of the processor; the processor is used to read the computer programs in the memory and perform the following operations: Receive a discovery message; If the relay forwarding identifier indicates that the end UE set allows the relay UE to forward, add the user information identifier of the first relay UE to the first relay UE set; Forward the discovery message after adding the user information identifier of the first relay UE; Among them, the discovery message carries at least one or more of the following parameters: The end UE set, which includes the user information identifier of the source end UE and the user information identifier of the destination end UE; The first relay UE set, which includes the user information identifiers of the relay UEs passed by from the source end UE to the first relay UE during the relay UE discovery process; The relay forwarding identifier, which is used to indicate whether the end UE set allows the relay UE to forward.

20. The relay UE according to claim 19, wherein, The receiving of the discovery message includes: Receive a discovery announcement message sent by other relay UEs; Or, receive a discovery request message sent by the source end UE or other relay UEs.

21. The relay UE according to claim 19 or 20, wherein, The discovery message also carries at least a hop count identifier, which is used to indicate the number of times the end UE set allows the relay UE to forward.

22. The relay UE according to claim 21, wherein, Before adding the user information identifier of the first relay UE to the first relay UE set, the processor is further used to perform the following operations: If the hop count identifier is not 0, subtract 1 from the hop count identifier and add the user information identifier of the first relay UE to the first relay UE set; If the hop count identifier is 0, discard the discovery message.

23. The relay UE according to claim 19 or 20, wherein, The discovery message also carries at least an end UE set identifier, which is used to uniquely identify the end UE set.

24. The relay UE according to claim 23, wherein, Before adding the user information identifier of the first relay UE to the first relay UE set, the processor is further used to perform the following operations: If the first relay UE has not forwarded the end UE set identifier, store the end UE set identifier locally and add the user information identifier of the first relay UE to the first relay UE set; If the first relay UE has already forwarded the end UE set identifier, discard the discovery message.

25. The relay UE according to claim 19, wherein, The processor is further used to perform the following operations: Receive a discovery response message sent by the destination end UE or the second relay UE; Send the discovery response message to the source end UE or the third relay UE; Among them, the discovery response message carries at least one or more of the following parameters: The end UE set; The second relay UE set, where the second relay UE set includes the user information identifier of the relay UE passed by the source UE to the destination UE during the relay UE discovery process and the layer 2 identifier of the relay UE, and the layer 2 identifier is used for the subsequent connection establishment process. The second relay UE is the relay UE after the first relay UE in the second relay UE set, and the third relay UE is the relay UE before the first relay UE in the relay UE set.

26. The relay UE according to claim 19, wherein, The processor is further configured to perform the following operations: Send a discovery announcement message; wherein, the discovery announcement message carries at least one or more of the following parameters: The set of end UEs, where the set of end UEs is the set of end UEs obtained by the first relay UE during the relay UE discovery process and / or the UE communication process; The third relay UE set, where the third relay UE set at least includes the user information identifier of the relay UE passed by the source UE in the set of end UEs to the first relay UE; The relay forwarding identifier, which is used to indicate whether the set of end UEs allows the relay UE to perform forwarding.

27. The relay UE according to claim 26, wherein, The discovery announcement message also carries at least a hop count identifier, which is used to indicate the number of times the set of end UEs allows the relay UE to forward. The hop count identifier is determined according to the initial hop count identifier and the hop count corresponding to the source UE in the set of end UEs reaching the first relay UE, and the initial hop count identifier is determined by the first relay UE or the policy control function PCF network element.

28. The relay UE according to claim 26, wherein, The discovery announcement message also carries at least a set of end UE identifiers, which are used to uniquely identify the set of end UEs, and the set of end UE identifiers is generated by the first relay UE or the PCF network element according to the set of end UEs.

29. The relay UE according to claim 26, wherein, The processor is further configured to perform the following operations: Send a registration request message to the access and mobility management function AMF network element; wherein, the registration request message carries at least a proximity service capability parameter, and the proximity service capability parameter includes the set of end UEs and / or the multi-hop relay identifier, and the multi-hop relay identifier is used to indicate that the first relay UE supports the discovery function of the multi-hop relay UE; Receive a non-access stratum NAS message sent by the PCF network element through the AMF network element; wherein, the NAS message carries at least a proximity service policy parameter, and the proximity service policy parameter includes the user information identifier of the first relay UE, the set of end UE identifiers, and / or the hop count identifier.

30. A user equipment UE, wherein, It includes a memory, a transceiver, and a processor. The memory is used to store a computer program. The transceiver is used to send and receive data under the control of the processor. The processor is used to read the computer program in the memory and perform the following operations: Send a first discovery request message; wherein, the first discovery request message carries at least one or more of the following parameters: The first set of UE at one end, the first set of UE at one end includes the user information identifier of the source UE and the user information identifier of the destination UE, and the UE at one end is the source UE in the first set of UE at one end; The first set of relay UE; The relay forwarding identifier, which is used to represent whether the first set of UE at one end allows the relay UE to forward.

31. The terminal UE according to claim 30, wherein, The processor is further configured to perform the following operations: Receive a second discovery request message sent by the relay UE; If the destination UE in the second set of UE at one end includes the UE at one end, send a discovery response message to the relay UE; Wherein, the second discovery request message carries at least one or more of the following parameters: The second set of UE at one end, the second set of UE at one end includes the user information identifier of the source UE and the user information identifier of the destination UE, and the UE at one end is the destination UE in the second set of UE at one end; The second set of relay UE, the second set of relay UE includes at least the user information identifier of the relay UE passed by from the source UE to the destination UE in the second set of UE at one end; The discovery response message carries at least one or more of the following parameters; The second set of UE at one end; The second set of relay UE.

32. The terminal UE according to claim 30, wherein, The first discovery request message also carries at least a hop count identifier, which is used to represent the number of times the first set of UE at one end allows the relay UE to forward, and the hop count identifier is determined by the UE at one end or the Policy Control Function (PCF) network element.

33. The terminal UE according to claim 30, wherein, The first discovery request message also carries at least a UE set identifier at one end, which is used to uniquely identify the first set of UE at one end, and the UE set identifier at one end is generated by the UE at one end or the PCF network element according to the first set of UE at one end.

34. The terminal UE according to claim 32 or 33, wherein The processor is further configured to perform the following operations: Send a registration request message to the Access and Mobility Management Function (AMF) network element; wherein, the registration request message carries at least a proximity service capability parameter, and the proximity service capability parameter includes the first set of UE at one end and / or a multi-hop relay identifier, and the multi-hop relay identifier is used to represent that the UE at one end supports the discovery function of the multi-hop relay UE; Receive a non-access stratum (NAS) message sent by the PCF network element through the AMF network element; wherein, the NAS message carries at least a proximity service policy parameter, and the proximity service policy parameter at least includes the user information identifier of the UE at one end, the UE set identifier at one end and / or the hop count identifier.

35. An Access and Mobility Management Function (AMF) network element, wherein, It includes a memory, a transceiver and a processor. Among them, the memory is used to store computer programs; the transceiver is used to transmit and receive data under the control of the processor; the processor is used to read the computer programs in the memory and perform the following operations: Receive a registration request message sent by the UE; Send a first NAS message to the Policy Control Function (PCF) network element; Receive a second NAS message sent by the PCF network element; Send a third NAS message to the UE; Among them, the registration request message carries at least a proximity service capability parameter, and the proximity service capability parameter includes an end UE set and / or a multi-hop relay identifier, and the multi-hop relay identifier is used to characterize that the UE supports the discovery function of multi-hop relay UEs; The first NAS message carries at least the proximity service capability parameter; The second NAS message carries at least a proximity service policy parameter, and the proximity service policy parameter includes a user information identifier of the UE, an end UE set identifier, and / or a hop count identifier; The third NAS message carries the proximity service policy parameter.

36. A Policy Control Function (PCF) network element, wherein, It includes a memory, a transceiver, and a processor. Among them, the memory is used to store computer programs; the transceiver is used to send and receive data under the control of the processor; the processor is used to read the computer programs in the memory and perform the following operations: Receive a first non-access stratum (NAS) message sent by an access and mobility management function (AMF) network element; Send a second NAS message to the AMF network element; Among them, the first NAS message carries at least a proximity service capability parameter, and the proximity service capability parameter includes an end UE set and / or a multi-hop relay identifier, and the multi-hop relay identifier is used to characterize that the UE supports the discovery function of multi-hop relay UEs; The second NAS message carries at least a proximity service policy parameter, and the proximity service policy parameter includes a user information identifier of the UE, an end UE set identifier, and / or a hop count identifier, and the end UE set identifier is generated based on the end UE set.

37. A discovery device for a relay user equipment (UE), wherein, The device is applied to a first relay UE, and the device includes: A first receiving unit, configured to receive a discovery message; An adding unit, configured to add a user information identifier of the first relay UE to a first relay UE set if a relay forwarding identifier indicates that the end UE set allows the relay UE to perform forwarding; A first sending unit, configured to forward the discovery message after adding the user information identifier of the first relay UE; Among them, the discovery message carries at least one or more of the following parameters: The end UE set, and the end UE set includes a user information identifier of a source end UE and a user information identifier of a destination end UE; The first relay UE set, and the first relay UE set includes user information identifiers of relay UEs passed by the source end UE to the first relay UE during the relay UE discovery process; The relay forwarding identifier, and the relay forwarding identifier is used to characterize whether the end UE set allows the relay UE to perform forwarding.

38. A discovery apparatus for a relay user equipment (UE), wherein, The device is applied to an end UE, and the device includes: A first sending unit, configured to send a first discovery request message; among them, the first discovery request message carries at least one or more of the following parameters: A first end UE set, and the first end UE set includes a user information identifier of a source end UE and a user information identifier of a destination end UE, and the end UE is the source end UE in the first end UE set; A first relay UE set; The relay forwarding identifier, and the relay forwarding identifier is used to characterize whether the first end UE set allows the relay UE to perform forwarding.

39. A discovery device for a relay user equipment (UE), wherein, The device is applied to an Access and Mobility Management Function (AMF) network element, and the device includes: A first receiving unit, configured to receive a registration request message sent by a UE; A first sending unit, configured to send a first Non-Access Stratum (NAS) message to a Policy Control Function (PCF) network element; A second receiving unit, configured to receive a second NAS message sent by the PCF network element; A second sending unit, configured to send a third NAS message to the UE; Wherein, the registration request message carries at least proximity service capability parameters, and the proximity service capability parameters include an end UE set and / or a multi-hop relay identifier, and the multi-hop relay identifier is used to characterize that the UE supports the discovery function of multi-hop relay UEs; The first NAS message carries at least the proximity service capability parameters; The second NAS message carries at least proximity service policy parameters, and the proximity service policy parameters include a user information identifier of the UE, an end UE set identifier, and / or a hop count identifier; The third NAS message carries the proximity service policy parameters.

40. A discovery device for a relay user equipment (UE), wherein, The device is applied to a Policy Control Function (PCF) network element, and the device includes: A receiving unit, configured to receive a first Non-Access Stratum (NAS) message sent by an Access and Mobility Management Function (AMF) network element; A sending unit, configured to send a second NAS message to the AMF network element; Wherein, the first NAS message carries at least proximity service capability parameters, and the proximity service capability parameters include an end UE set and / or a multi-hop relay identifier, and the multi-hop relay identifier is used to characterize that the UE supports the discovery function of multi-hop relay UEs; Wherein, the second NAS message carries at least proximity service policy parameters, and the proximity service policy parameters include a user information identifier of the UE, an end UE set identifier, and / or a hop count identifier, and the end UE set identifier is generated based on the end UE set.

41. A computer-readable storage medium having a computer program stored thereon, wherein, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 11, or 12 to 16, or 17 or 18.

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