Local identifier allocation in multi-hop sidelink UE-to-UE relay

Abstract

The present disclosure provides a method for wireless communication between user equipments (UEs), comprising: a second relay UE receiving a UE-to-UE relay discovery announcement message from a first relay UE; the second relay UE determines whether to transmit a first message to a first remote UE connected to the second relay UE based on the UE-to-UE relay discovery announcement message, where the first message is used by the second relay UE to reassign a local ID to the first remote UE. Other aspects are also provided.

Description

Local identifier allocation in multi-hop sidelink UE-to-UE relay Technical Field

[0001] The present disclosure relates to the field of communication systems, and more particularly, to a method for wireless communication between user equipments (UEs), a chip thereof, a computer-readable storage medium, and a computer program product, as well as a first relay UE and a second relay UE. Background Art

[0002] In Rel_18, the requirements for sidelink relay are not limited to supporting 5G ProSe UE-to-Network Relay (5G Proximity Service U2N Relay), but also need to support U2U (UE-to-UE) relay so that when there is no network coverage, the relay UE can send the sidelink data of the source UE to the target UE, and the remote UE can also establish a connection with another remote UE through the relay UE.

[0003] The structure of the Service-based Radio Access Protocol (SRAP) header is currently under discussion in Rel_18, and several proposals have been proposed. However, with the anticipated introduction of multi-hop relays in Rel_19, RAN2 expects existing single-hop U2U sidelink relays to be compatible with future multi-hop U2U sidelink relays. This complicates the design of the SRAP header.

[0004] It should be noted that the content described in this section does not constitute or should not be regarded as an admission of any prior art.

[0005] Summary of the Invention

[0006] In order to overcome at least one of the above technical problems, the present disclosure proposes local identifier allocation in multi-hop side link UE-to-UE relay, which can ensure that the local identifiers ID allocated to multiple relay UEs are unique, thereby reducing the occurrence of local ID conflicts and improving communication efficiency.

[0007] One aspect of the present disclosure provides a method for wireless communication between user equipment (UE), including: a second relay UE receiving a UE-to-UE relay discovery announcement message from a first relay UE; the second relay UE determining whether to transmit a first message to a first remote UE connected to the second relay UE based on the UE-to-UE relay discovery announcement message, wherein the first message is used by the second relay UE to reallocate a local ID to the first remote UE.

[0008] According to an example embodiment, the UE-to-UE relay discovery announcement message includes at least a first subset of a set of UE identifier (ID) mapping relationships associated with the first relay UE, the UE ID mapping relationship set including a mapping relationship between a UE Layer 2 identifier (L2 ID) and a local ID of each of a plurality of UEs connected to and / or discovered by the first relay UE, wherein the local ID of each of the plurality of UEs is uniquely assigned by the first relay UE, and wherein the first subset includes a mapping relationship between a local ID assigned by the first relay UE for a first remote UE to which the first relay UE is connected and the UE L2 ID of the first remote UE.

[0009] According to an example embodiment, the second relay UE determines whether to transmit a first message to a second remote UE connected to the second relay UE based on the UE-to-UE relay discovery announcement message, including: when the local ID of one of the multiple UEs connected and / or discovered by the first relay UE conflicts with the local ID assigned to the first remote UE by the second relay UE, transmitting the first message to the second remote UE.

[0010] According to an example embodiment, the method further includes: transmitting, by the second relay UE, the first message to the second remote UE; and receiving, by the second relay UE, a first response message from the second remote UE.

[0011] According to an example embodiment, the second relay UE is configured to perform any one of the example embodiments of the above method.

[0012] One aspect of the present disclosure provides a method for wireless communication between user equipment (UE), including: a first relay UE forwarding a UE-to-UE relay discovery request message to a second relay UE, where the second relay UE is located between the first relay UE and a first remote UE, including: the first relay UE forwarding the UE-to-UE relay discovery request message together with at least a first subset of a UE identifier ID mapping relationship set associated with the first relay UE to the second relay UE.

[0013] According to an example embodiment, the UE ID mapping relationship set includes a first mapping relationship between a UE Layer 2 identifier L2 ID and a local ID of each UE in a first plurality of UEs connected to and / or discovered by the first relay UE, the local ID of each UE in the first plurality of UEs being uniquely assigned by the first relay UE, and wherein the first subset includes a second mapping relationship between a UE Layer 2 identifier L2 ID and a local ID of a second remote UE requested to be discovered.

[0014] According to an example embodiment, the method further includes: receiving, by the first relay UE, the UE-to-UE relay discovery request message from the second remote UE, wherein the UE-to-UE relay discovery request message includes the UE L2 IDs of the second remote UE and the first remote UE, respectively; receiving, by the first relay UE, a UE-to-UE relay discovery response message from the second relay UE; and forwarding, by the first relay UE, the UE-to-UE relay discovery response message to the second remote UE.

[0015] According to an example embodiment, the UE-to-UE relay discovery response message received by the first relay UE from the second relay UE is transmitted by the second relay UE upon determining that the first mapping relationship includes a UE L2 ID of a UE to which the second relay UE is connected.

[0016] According to an example embodiment, the relay discovery response message includes a second mapping relationship between a UE L2 ID of each UE in a second plurality of UEs linked to and / or discovered by the second relay UE and a local identifier (ID), wherein the local ID of each UE in the second plurality of UEs is uniquely assigned by the second relay UE, and the second plurality of UEs includes the first remote UE.

[0017] According to an example embodiment, forwarding the UE-to-UE relay discovery response message to the second remote UE by the first relay UE includes: allocating, by the first relay UE, a local ID to the second remote UE based on the second mapping relationship; and forwarding, by the first relay UE, the local ID allocated to the second remote UE and the first mapping relationship between the UE L2 ID of the first remote UE and the local ID, together with the UE-to-UE relay discovery response message, to the second remote UE.

[0018] One aspect of the present disclosure provides a first relay user equipment (UE), which is configured to perform any embodiment of the above method.

[0019] One aspect of the present disclosure provides a method for wireless communication between user equipments (UEs), including: a second relay UE receiving a UE-to-UE relay discovery request message from a first relay UE, wherein the UE-to-UE relay discovery request message includes a UE Layer 2 identifier (L2 ID) of each of a second remote UE and the first remote UE, and the first relay UE is located between the second remote UE and the second relay UE.

[0020] According to an example embodiment, the UE-to-UE relay discovery request message includes at least a first subset of a set of UE identifier (ID) mapping relationships associated with the first relay UE, the set of UE ID mapping relationships including a first mapping relationship between a UE L2 ID of each UE in a first plurality of UEs connected to and / or discovered by the first relay UE and a local identifier (ID), the local ID of each UE in the first plurality of UEs being uniquely assigned by the first relay UE, and wherein the first subset includes a mapping relationship between a local ID assigned by the first relay UE for a second remote UE to which the first relay UE is connected and the UE L2 ID of the second remote UE.

[0021] According to an example embodiment, the method further includes transmitting, by the second relay UE, a UE-to-UE relay discovery response message to the first relay UE, so that the first relay UE forwards the UE-to-UE relay discovery response message to the second remote UE.

[0022] According to an example embodiment, the method further includes: the second relay UE determining, based on the UE-to-UE relay discovery request message, whether to transmit the first message to the terminal UE connected to the second relay UE.

[0023] According to an example embodiment, the second relay UE determines whether to transmit a first message to a terminal UE connected to the second relay UE based on the UE-to-UE relay discovery request message, including: in response to an identification from the UE-to-UE relay discovery request message that there is a local ID that conflicts with the local ID assigned to the terminal UE by the second relay UE, determining to transmit a first message to the terminal UE, wherein the first message includes a new local ID assigned to the terminal UE by the second relay UE.

[0024] According to an example embodiment, the method further includes: transmitting, by the second relay UE, the first message to the terminal UE; and receiving, by the second relay UE, a first response message from the terminal UE.

[0025] According to an example embodiment, the above method further includes: the second relay UE finds the first remote UE based on the UE L2 ID of the first remote UE included in the relay discovery request message, and forwards the UE-to-UE relay discovery request message to the first remote UE; and the second relay UE receives a UE-to-UE relay discovery response message from the first remote UE.

[0026] According to an example embodiment, forwarding, by the second relay UE, the UE-to-UE relay discovery request message to the first remote UE includes: forwarding, by the second relay UE, the UE-to-UE relay discovery request message together with a second mapping relationship to the first remote UE.

[0027] According to an example embodiment, the second mapping relationship includes: a mapping relationship between a UE L2 ID of each of a second plurality of UEs to which the second relay UE has been connected and / or discovered before finding the first remote UE and a local identifier (ID), wherein the local ID of each of the second plurality of UEs is uniquely assigned by the second relay UE, and an additional mapping relationship between the UE L2 ID of the first remote UE and a local ID assigned to the first remote UE by the second relay UE based on the mapping relationship.

[0028] According to an example embodiment, transmitting, by the second relay UE, a UE-to-UE relay discovery response message to the first relay UE includes transmitting, by the second relay UE, the UE-to-UE relay discovery response message together with the second mapping relationship to the first relay UE.

[0029] According to an example embodiment, the first relay UE forwarding the UE-to-UE relay discovery response message to the second remote UE includes: the first relay UE assigning a local ID to the second remote UE based on the second mapping relationship received from the first relay UE; and the first relay UE forwarding the local ID assigned to the second remote UE and the additional mapping relationship together with the UE-to-UE relay discovery response message to the second remote UE.

[0030] One aspect of the present disclosure provides a second relay user equipment (UE), which is configured to perform any embodiment of the above method.

[0031] One aspect of the present disclosure provides a wireless communication method for a first relay user equipment (UE), comprising: the first relay UE transmitting a first response message to a connected first remote UE in response to receiving a first message from the first remote UE, wherein the first response message includes a local identifier (ID) allocated by the first relay UE to the first remote UE.

[0032] According to an example embodiment, the step further includes: the first relay UE transmitting a second message to a second relay UE, wherein the second message includes the local ID of the first remote UE.

[0033] According to an example embodiment, the second relay UE is connected to a second remote UE, and the second relay UE allocates the local ID to the second remote UE, and wherein the method further comprises: the first relay UE receiving a second response message from the second relay UE.

[0034] According to an example embodiment, in a case where the local ID allocated by the second relay UE to the second remote UE conflicts with the local ID allocated by the first relay UE to the first remote UE, the second response message includes the second relay UE reallocating the local ID to the first remote UE, and wherein the first response message transmitted by the first relay UE to the first remote UE includes the second relay UE reallocating the local ID to the first remote UE.

[0035] According to an example embodiment, a third relay UE is further included between the first relay UE and the second relay UE, and wherein the first relay UE transmitting the second message to the second relay UE includes: the first relay UE transmitting the second message to the third relay UE, so that the third relay UE adds all local IDs allocated by the third relay UE to the second message, and transmits the resulting message to the second relay UE.

[0036] According to an example embodiment, the method further includes: the first relay UE receiving a third message from the first remote UE, wherein the third message includes a UE Layer 2 identifier (L2 ID) of a second remote UE sent by the first remote UE to the first relay UE and used for the first remote UE requesting to communicate with it.

[0037] According to an example embodiment, the method further includes: the first relay UE transmitting a fourth message to the second relay UE in response to receiving a discovery message broadcast by a second relay UE among the plurality of relay UEs, wherein the second relay UE is connected to the second remote UE, and the second relay UE has allocated the local ID for the second remote UE, and the discovery message includes the UE L2 ID of the second remote UE, and wherein the fourth message includes all local IDs allocated by the first relay UE and the UE L2 ID of the second remote UE.

[0038] According to an example embodiment, the method further includes: the first relay UE receiving a fourth response message from the second relay UE, and forwarding the fourth response message to the first remote UE.

[0039] According to an example embodiment, in a case where the allocated local ID of the second remote UE conflicts with the local ID allocated by the first relay UE to the first remote UE, the fourth response message includes the second relay UE reallocating the local ID to the second remote UE, and wherein the fourth response message received by the first relay UE from the second relay UE includes the second relay UE reallocating the local ID to the second remote UE.

[0040] One aspect of the present disclosure provides a first relay user equipment (UE), which is configured to perform any embodiment of the above method.

[0041] One aspect of the present disclosure provides a chip, comprising: a processor configured to call and execute a computer program stored in a memory, so that a device in which the chip is installed executes a method of an embodiment of any aspect of the present disclosure.

[0042] One aspect of the present disclosure provides a computer-readable storage medium having a computer program stored therein, wherein the computer program enables a computer to execute a method according to any one of the embodiments of the present disclosure.

[0043] One aspect of the present disclosure provides a computer program product, comprising a computer program, wherein the computer program enables a computer to execute the method of any embodiment of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the embodiments of the present disclosure or related technologies, the following drawings will be briefly introduced in the embodiments. Obviously, the drawings are only some embodiments of the present disclosure, and ordinary technicians in this field can derive other drawings based on these drawings without inventive work.

[0045] FIG1 illustrates an exemplary scenario in which there is a multi-hop U2U sidelink relay according to some embodiments of the present disclosure.

[0046] FIG2 illustrates a signaling diagram of a sidelink RRC configuration according to some embodiments of the present disclosure.

[0047] FIG3 illustrates a signaling diagram of a first exemplary multi-hop U2U sidelink relay according to some embodiments of the present disclosure.

[0048] FIG4 illustrates a signaling diagram of a second exemplary multi-hop U2U sidelink relay according to some embodiments of the present disclosure.

[0049] FIG5 illustrates an exemplary collision scenario for multi-hop U2U sidelink relay according to some embodiments of the present disclosure.

[0050] FIG6 illustrates example UE Layer 2 identifier (UE L2 ID) indication bits according to some embodiments of the present disclosure.

[0051] FIG7 illustrates a signaling diagram of a third exemplary multi-hop U2U sidelink relay according to some embodiments of the present disclosure.

[0052] FIG8 illustrates an example SRAP header including a full UE L2 ID according to some embodiments of the present disclosure.

[0053] FIG9 illustrates a signaling diagram of a fourth exemplary multi-hop U2U sidelink relay according to some embodiments of the present disclosure.

[0054] FIG10 illustrates a signaling diagram of a fifth exemplary multi-hop U2U sidelink relay according to some embodiments of the present disclosure.

[0055] 11 is a block diagram of an example system for wireless communications according to an embodiment of the disclosure. DETAILED DESCRIPTION

[0056] The embodiments of the present disclosure describe technical matters, structural features, objectives and effects in detail with reference to the accompanying drawings, as described below. Specifically, the terms in the embodiments of the present disclosure are only used to describe the purpose of specific embodiments, rather than to limit the present disclosure.

[0057] In this disclosure, "A or B" may mean "only A," "only B," or "both A and B."

[0058] In other words, in the present disclosure, "A or B" may be interpreted as "A and / or B." For example, in the present disclosure, "A, B or C" may mean "only A," "only B," "only C," or "any combination of A, B, and C."

[0059] As used in this disclosure, a slash ( / ) or a comma may mean "and / or". For example, "A / B" may mean "A and / or B". Thus, "A / B" may mean "only A", "only B", or "both A and B". For example, "A, B, C" may mean "A, B, or C".

[0060] In the present disclosure, “at least one of A and B” may mean “only A”, “only B”, or “both A and B”. In addition, in the present disclosure, the expression “at least one of A or B” or “at least one of A and / or B” may be interpreted as “at least one of A and B”.

[0061] In addition, in the present disclosure, “at least one of A, B, and C” may mean “only A,” “only B,” “only C,” or “any combination of A, B, and C.” In addition, “at least one of A, B, or C” or “at least one of A, B, and / or C” may mean “at least one of A, B, and C.”

[0062] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the described features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0063] The existing technology has the following problems: if the ID is allocated by the relay UE, there will be a problem, that is, when introducing multi-hop U2U relay, how to ensure that the IDs allocated by two or more relay UEs will not be repeated?

[0064] For example, referring to Figure 1, when the source UE (which may also be referred to as the source remote UE or the second remote UE in this disclosure) establishes a connection with the relay UE1, the relay UE1 will assign a source UE local ID to the source UE. However, after the relay UE1 (which may also be referred to as the first relay UE in this disclosure) and the relay UE2 (which may also be referred to as the second relay UE in this disclosure) establish a connection, should the relay UE1 or the relay UE2 assign the ID? Assuming that we let the relay UE2 assign it, this may cause a conflict between the UE ID assigned by the relay UE1 to the source UE and the UE ID assigned by the relay UE2 to the target UE (which may also be referred to as the target remote UE in this disclosure). Similarly, if the target UE is not considered, the relay UE1 assigns a local ID to the source UE, and the relay UE2 assigns a local ID to itself, a conflict may also occur. It is necessary to solve the problem of how to avoid ID conflicts in multi-hop U2U relays.

[0065] Therefore, the present disclosure proposes a more efficient and simple method to achieve local identifier (ID) allocation in multi-hop sidelink UE-to-UE relay.

[0066] Therefore, the present disclosure proposes a wireless communication method between user equipment (UEs). This method can be used for local identifier allocation in multi-hop sidelink UE-to-UE relays, ensuring that the local identifiers (IDs) allocated to multiple relay UEs are unique, thereby reducing the occurrence of local ID conflicts and improving communication efficiency.

[0067] In some embodiments, user equipment (UE) may be dispersed throughout the wireless communication network, and the UE may be fixed or mobile. A UE may also be referred to as a terminal, mobile station, subscriber unit, station, etc. A UE 115 may be a cellular phone, personal digital assistant (PDA), wireless modem, wireless communication device, handheld device, tablet computer, laptop computer, cordless phone, wireless local loop (WLL) station, etc. In one aspect, a UE 115 may be a device including a universal integrated circuit card (UICC). In another aspect, a UE may not include a UICC. In some aspects, a UE 115 not including a UICC may also be referred to as an IoT device or an Internet of Everything (IoE) device. Although the UE is illustrated in various figures as a mobile smartphone-type device in a wireless communication network, a UE may also be a machine specifically configured for connected communications, including machine-type communications (MTC), enhanced MTC (eMTC), narrowband IoT (NB-IoT), etc. Furthermore, a UE may communicate with any type of base station node (such as a gNB) and with any type of other UE.

[0068] As used in this disclosure, the terms "source user terminal (UE)", "target UE", and "remote UE" are referred to relative to the relay UE. In some cases, unless otherwise specified, the terms "source UE", "target UE", and / or "remote UE" can be used interchangeably.

[0069] Figure 1 illustrates an exemplary scenario involving a multi-hop U2U sidelink relay according to some embodiments of the present disclosure. As shown, relay UE 1 and relay UE 2 need to establish a connection (e.g., a Radio Resource Control (RRC) connection). According to the current sidelink RRC connection establishment procedure (see 38.331), there is no master-slave relationship, and any UE can initiate a link configuration procedure (e.g., an RRC Reconfiguration Sidelink procedure).

[0070] In some embodiments of the present disclosure, a single UE is designated to resolve the conflict. Figure 2 illustrates a signaling diagram for sidelink RRC configuration according to some embodiments of the present disclosure. Referring to Figure 2 , it is assumed that, in the 38.331 specification, the UE initiating RRCReconfigurationSidelink is designated as the slave relay UE, and the UE initiating RRCReconfigurationCompleteSidelink is designated as the master relay UE.

[0071] The RRCReconfigurationSidelink process does not involve the interaction of the Layer 2 UE identifier (L2UE ID). The interaction of the Layer 2 UE ID is performed during the discovery process. However, since the present disclosure requires coordination of local IDs, the problem of local ID conflicts cannot be resolved at the discovery layer. This is because the discovery layer is not a confirmed message layer. The local ID should be allocated by PC5-RRC. Therefore, the signaling diagrams of the first to third exemplary multi-hop U2U sidelink relays of the present invention correspond to the coordination of local ID allocation at the PC5-RRC layer.

[0072] In some embodiments of the present disclosure, a slave UE carries the UE IDs of all assigned remote UEs in a configuration message (e.g., an RRCReconfigurationSidelink message). Upon receiving a configuration message (e.g., an RRCReconfigurationSidelink message), if a conflict exists between the UE ID assigned by the master relay UE and the UE ID assigned by the slave relay UE, the master relay UE sends a new UE ID and simultaneously sends the old, conflicting UE ID to the slave relay UE. The slave relay UE then updates the source UE's ID.

[0073] In some embodiments of the present disclosure, the slave UE carries the UE ID of an assigned remote UE in a configuration message (such as an RRCReconfigurationSidelink message, etc.) Exemplarily, the remote UE may be a UE requesting discovery (eg, requesting discovery of other remote UEs).

[0074] In some embodiments of the present disclosure, the SRAP header contains the local ID of the sending UE and the local ID of the next hop, rather than the initial source local ID and the final destination local ID. Therefore, each relay UE needs to interact with other relay UEs to update its assigned local ID, but does not need to communicate the source and destination local IDs across the entire link. Consequently, the source UE may not know the local ID of the destination UE.

[0075] FIG3 illustrates a signaling diagram of a first exemplary multi-hop U2U sidelink relay according to some embodiments of the present disclosure.

[0076] Exemplarily, step or signaling 1: the source UE sends an RRCReconfiguration message to the relay UE1, carrying the complete L2UE ID (note: the L2UE ID has been exchanged in the previous discovery process, so it may not be necessary to carry it again in some cases).

[0077] Exemplarily, step or signaling 1a: the relay UE1 allocates a local ID to the source UE and sends its own local ID to the source UE.

[0078] Exemplarily, step or signaling 2, 2a: repeat the steps of step or signaling 1, 1a respectively.

[0079] Exemplarily, step or signaling 3: Relay UE1 and relay UE2 need to establish a connection. Assume that relay UE1 sends an RRCReconfigurationSidelink message to relay UE2 (in some cases, it may include a Layer 2UE ID list and a local ID list for all source UEs, and in other cases, it may include a Layer 2UE ID list and a local ID list for only one or a given number of source UEs). Relay UE1 needs to send its assigned local ID and the local IDs of a corresponding number of (source) remote UEs connected to relay UE1 to relay UE2, so that relay UE2 can resolve potential local ID conflicts.

[0080] It should be noted that when the number of L2UE ID and local ID pairs of the source UE included in the configuration message (e.g., RRCReconfigurationSidelink message) sent by relay UE1 to relay UE2 is equal to 1, it corresponds to the first subset in the exemplary embodiments of the present disclosure. In other words, the concept of the first subset (i.e., the number of mapping relationships between L2UE IDs and local IDs in messages (e.g., configuration messages) sent by relay UE (e.g., relay UE1) is 1) can also be applied to other examples, other embodiments, or other exemplary embodiments of the present disclosure. The present disclosure is not intended to limit the first subset to the embodiments in which it appears, and is not limited to any message (including response messages, ACK messages, completion messages, etc.).

[0081] Exemplarily, step or signaling 4: the relay UE2 determines whether there is a local ID that conflicts with its already allocated local ID.

[0082] Exemplarily, step or signaling 5: If a conflict exists, relay UE2 resolves the conflict (this example specifies that the relay UE receiving the RRCReconfigurationSidelink message resolves the local ID conflict). Relay UE2 sends an RRCReconfigurationCompleteSidelink message to relay UE1 (including the source UE's old local ID / the source UE's new local ID / the source UE's UE L2 ID mapping, as well as the UE L2 ID list and local ID mapping list of all target UEs). The message includes the UE L2 ID and local ID of the source UE to which the local ID is reassigned, as well as the UE L2 ID list and local ID mapping list of all (target) UEs connected to relay UE2.

[0083] Exemplarily, step or signaling 6: If there is a conflict, and the modified local ID has been obtained from the relay UE2, the relay UE1 will send an RRCReconfigurationSidelink message to the source remote UE, and the message includes the newly allocated local ID.

[0084] Exemplarily, step or signaling 6a: the source UE sends an RRCReconfigurationCompleteSidelink message to the relay UE1.

[0085] Optional, exemplary, step or signaling 3a: When relay UE3 exists between relay UE1 and relay UE2, relay UE3 adds the local ID assigned by relay 3 when forwarding signaling 3 to relay UE2, so as to help relay UE2 resolve local ID conflicts. That is, when a local ID conflict occurs and relay UE2 needs to resolve the local ID conflict, the local ID reallocated by relay UE2 to certain UE(s) with a local ID conflict will not conflict with the local ID assigned by relay UE1 to itself and the local ID of the source remote UE connected to relay UE1, nor will it conflict with the local ID assigned by relay UE3, thereby improving the efficiency of local ID conflict resolution.

[0086] Optional, exemplary, step or signaling 5a: When relay UE3 exists between relay UE1 and relay UE2, since it is relay UE2 rather than relay UE1 that resolves the conflict when a local ID conflict occurs, relay UE3 may forward signaling 5 to relay UE1.

[0087] FIG4 illustrates a signaling diagram of a second exemplary multi-hop U2U sidelink relay according to some embodiments of the present disclosure.

[0088] The key points of this embodiment are as follows:

[0089] 1. How to send the local ID of the target remote UE to the source UE, and how to send the local ID of the source remote UE to the target remote UE.

[0090] 2. Relay UE1 needs to know that the ID of the target UE is attached to relay UE2 so that the data of the source UE can be correctly sent to relay UE2.

[0091] Exemplarily, step or signaling 1-1c: Relay UE1 and relay UE2 allocate local IDs to the source remote UE and target remote UE respectively through a configuration message (eg, RRCReconfigurationSidelink message).

[0092] Exemplary step or signaling 2: When the source UE needs to discover and communicate with the target UE, the source UE will send a configuration message (e.g., RRCReconfigurationSidelink message) to the relay UE1 (to request the local ID of the target UE) and send the target UE's Layer 2 ID to the relay UE1 to request the target UE's local ID. The relay UE1 is responsible for finding a relay UE that can connect to the target remote UE.

[0093] Exemplarily, step or signaling 3: the relay UE2 includes the UE L2 IDs of all target UEs in the broadcast discovery message.

[0094] Exemplarily, step or signaling 4: When relay UE1 discovers that the discovery message broadcast by relay UE2 contains the UE L2 ID of the target UE, relay UE1 decides to establish a connection (e.g., an RRC connection) with relay UE2. In this connection, relay UE1 needs to obtain the local ID of the target remote UE and inform the target remote UE of the local ID of the source remote UE. Therefore, relay UE1 sends a configuration message (e.g., an RRCReconfigurationSidelink message) (which contains a remote UE local ID / remote UE UE L2 ID mapping list, the local ID of the source remote UE / UE L2 ID, and the UE L2 ID of the target UE).

[0095] Reference is now made to Figure 5. Figure 5 illustrates an exemplary collision scenario for multi-hop U2U sidelink relay according to some embodiments of the present disclosure.

[0096] As shown in the figure, it is important to note that relay UE2 determines whether the local ID of the source remote UE conflicts with the local ID of a certain UE carried by relay UE2. The certain UE here is not limited to the target UE specified by the source remote UE (for example, target remote UE2 in Figure 5). This is because when relay UE2 receives an SRAP PDU from another UE (for example, target remote UE1 in Figure 5) without conflict, if the target UE ID conflicts with the source remote UE ID of relay UE1, relay UE2 will not be able to determine the true target UE.

[0097] Therefore, when handling a conflict, the relay UE2 needs to comprehensively consider the target UE specified by the source remote UE and other possible UEs to ensure that the ID of the target UE is correctly resolved and that correct communication is performed.

[0098] Returning to Figure 4 , exemplary step or signaling 5: If relay UE2 finds that the local ID of the remote UE conflicts with the local ID of the target UE, relay UE2 will send a configuration message (e.g., an RRCReconfigurationSidelink message) to reallocate the local ID. Otherwise, relay UE2 will transfer the local ID and UE L2 ID of the source remote UE and all remote UEs connected to relay UE1 to the target remote UE.

[0099] Exemplary step or signaling 5a: the target UE sends a confirmation message (such as RRCReconfigurationCompleteSidelink message) to the relay UE2.

[0100] Exemplarily, step or signaling 6: relay UE2 sends a configuration confirmation message (such as RRCReconfigurationCompleteSidelink message) to relay UE1 to transfer the UE L2 ID and local ID of the target UE.

[0101] Exemplarily, step or signaling 7: the relay UE1 sends a configuration confirmation message (such as an RRCReconfigurationCompleteSidelink message) to the source remote UE1 to transfer the UE L2ID and local ID of the target UE.

[0102] FIG6 illustrates example UE Layer 2 identifier (UE L2ID) indication bits according to some embodiments of the present disclosure.

[0103] The purpose of introducing the local ID is to reduce the signaling overhead on the side link. If a local ID conflict occurs, the full UE L2 ID will be used in the SRAP.

[0104] If a complete UE L2 ID is used, the following two points need to be noted:

[0105] ● The source and target remote UEs need to be instructed to use the UE L2 ID in the SRAP. This ensures that the identities of the source and target UEs are correctly identified and handled during the communication process.

[0106] In the SRAP header in Figure 6, the second R bit is used to indicate whether the full UE L2 ID or the UE local ID is used. Of course, in other implementations, newly added bits or existing bits can be used to indicate whether the full UE L2 ID or the UE local ID is used, and this disclosure does not impose any limitations on this.

[0107] 2. The source remote UE needs to be instructed to use the full UE L2 ID when setting the source / target ID in the SRAP. First, Relay UE1 obtains the target remote UE's local ID from Relay UE2. It then discovers that the local IDs of the source and target remote UEs conflict. Therefore, Relay UE1 notifies both the source and target remote UEs, via Relay UE2, to use the full UE L2 ID for this communication pair.

[0108] By using, for example but not limited to, the second R bit to indicate the adopted ID type, and through negotiation and notification during the communication process, it is possible to ensure that the IDs of the source UE and target UE are correctly set in the SRAP and resolve possible conflicts.

[0109] FIG7 illustrates a signaling diagram of a third exemplary multi-hop U2U sidelink relay according to some embodiments of the present disclosure.

[0110] Exemplarily, step or signaling 1: Relay UE1 and relay UE2 allocate local IDs to the source remote UE and the target remote UE respectively.

[0111] Exemplarily, step or signaling 2: when the source UE needs to discover and communicate with the target UE, the source UE sends a message to the relay UE1, sending the UE L2 ID of the target UE to the relay UE1, and the relay UE1 searches for a relay UE that can connect to the target remote UE.

[0112] Exemplarily, step or signaling 3: the relay UE2 includes the UE L2 IDs of all target UEs in the broadcast discovery message.

[0113] Exemplarily, step or signaling 4: When relay UE1 discovers that the discovery message broadcast by relay UE2 contains the UE L2 ID of the target UE, it decides to establish an RRC connection with relay UE2. In this RRC connection, it is necessary to obtain the local ID of the target remote UE from relay UE2 and inform the target remote UE of the local ID of the source remote UE. Therefore, a configuration message (such as an RRCReconfigurationSidelink message) is sent (which includes a remote UE local ID / remote UE UE L2 ID mapping list, the local ID of the source remote UE / UE L2 ID, and the UE L2 ID of the target UE).

[0114] Exemplarily, step or signaling 5: Relay UE2 determines whether the local ID of the source remote UE conflicts with the local ID of a UE carried by the relay UE. If relay UE2 finds that the local ID of the remote UE conflicts with the local ID of the target UE, relay UE2 instructs the target UE to use the UE L2 ID when sending to the source UE.

[0115] Exemplary step or signaling 6: Relay UE2 sends a configuration message (such as RRCReconfigurationSidelink message) to the target remote UE (which includes the UE L2 ID of the source UE and the UE L2 ID indicator). The purpose of this message is to inform the target remote UE to use the full UE L2 ID when sending to the source UE.

[0116] Exemplarily, step or signaling 7: relay UE2 sends a configuration completion message (such as RRCReconfigurationCompleteSidelink message) (including the UE L2 ID of the target UE and the UE L2 ID indicator) to relay UE1 to notify the use of the complete UE L2 ID for the specific target UE.

[0117] Exemplarily, step or signaling 8: the relay UE1 sends a configuration message (such as RRCReconfigurationSidelink message) (which includes the UE L2 ID of the target UE and the UE L2 ID indicator) to the source remote UE to notify the use of the complete UE L2 ID for the specific target UE.

[0118] Therefore, an enhanced SRAP header is needed. Figure 8 illustrates an example SRAP header including a full UE L2 ID according to some embodiments of the present disclosure. As shown, one bit F / L is used to indicate whether the full UE L2 ID or the local ID is used.

[0119] Therefore, through appropriate indication and notification, it is ensured that the IDs of the source UE and the target UE are correctly set during the communication process and possible conflicts are resolved.

[0120] In a relay system, the UE local ID of each remote UE is assigned by the relay UE it is connected to. Therefore, the conflict resolution is likely to be performed by the relay UE itself.

[0121] In the existing discovery mechanism, the 23.304 standard introduces two discovery models, namely Model A and Model B:

[0122] Model A: The relay UE broadcasts a discovery message to notify other relay UEs and remote UEs of the target UE to which it is connected. Other relay UEs and remote UEs can then choose to establish a connection with the target UE based on this information.

[0123] Model B: The relay UE actively discovers the target UE by sending a discovery request message to the target UE. After receiving the request, the target UE can choose to establish a connection with the relay UE.

[0124] These two discovery models provide different ways to discover and establish connections.

[0125] Figure 9 illustrates a signaling diagram of a fourth exemplary multi-hop U2U sidelink relay according to some embodiments of the present disclosure. Figure 9 provides a conflict resolution method corresponding to Model A.

[0126] Exemplarily, steps or signaling 1, 1a: UE-to-UE relays 1 and 2 have discovered other UEs in the vicinity.

[0127] Exemplarily, step or signaling 2: the relay UE1 includes a mapping relationship table of the UE L2 IDs and UE local IDs of all connected or discovered UEs in the discovery announcement message. This can provide a complete list so that other devices can understand the identification information of the UE to which the relay UE1 is connected. It should be noted that due to various factors, this process may face a greater risk of failure and / or this process may face a greater signaling overhead. In practice, whether to include a mapping relationship table of the UE L2 IDs and UE local IDs of all connected or discovered UEs in the discovery announcement message depends on the trade-off between local ID conflict resolution and signaling overhead.

[0128] In some embodiments of the present disclosure, a mapping relationship table between the UE L2 ID and the UE local ID of a connected or discovered UE may be included in a discovery announcement message or other messages (such as a configuration message, etc.), rather than a mapping relationship table between the UE L2 ID and the UE local ID of all connected or discovered UEs. This can effectively reduce signaling overhead.

[0129] Relay UE2 determines that some UE local IDs assigned by relay UE1 conflict with UE local IDs assigned by itself to some remote UEs (such as remote UE2). When a conflict is found, relay UE2 needs to take measures to resolve the conflict to ensure that each UE's identity is unique.

[0130] Exemplary step or signaling 3: Relay UE2 reassigns a local ID to terminal UE2 (also referred to as the first remote UE in this disclosure). This is to resolve conflicts and ensure that terminal UE2 has an identifier that does not conflict with other UEs. By reassigning the local ID, conflicts can be eliminated and correct identification and connection can be ensured during communication.

[0131] FIG10 illustrates a signaling diagram of a fifth exemplary multi-hop U2U sidelink relay according to some embodiments of the present disclosure.

[0132] Exemplarily, step or signaling 1: the terminal UE1 as the discoverer sends a UE-to-UE relay discovery request message to the relay UE1.

[0133] Exemplary step or signaling 2: The original UE-to-UE relay discovery request message only contains the UE L2 IDs of the source and target remote UEs. However, when relay UE1 forwards the message, to resolve conflicts, relay UE1 needs to add a mapping table containing the UE L2 IDs and local IDs of all connected and / or discovered UEs to the message. This provides a complete list, allowing other devices to understand the identification information of the UEs to which relay UE1 is connected.

[0134] Exemplarily, step or signaling 3: relay UE2 determines that some local IDs conflict with local IDs allocated to terminal UE3 and terminal UE2. When a conflict is found, relay UE2 needs to take measures to resolve the conflict to ensure that each UE's identity is unique.

[0135] Exemplary steps or signaling 4 / 5: Relay UE2 reassigns a local ID to terminal UE3. This is to resolve conflicts and ensure that terminal UE3 has an identifier that does not conflict with other UEs. By reassigning the UE local ID, conflicts are eliminated and correct identification and connection are ensured during communication.

[0136] Exemplarily, step or signaling 6: adding a mapping between the UE L2ID and the local ID in the UE-to-UE relay discovery request message. This adds a solution for allocating the UE local ID in the discovery request message.

[0137] Exemplarily, step or signaling 7: the terminal UE2 confirms the allocated local ID.

[0138] Exemplarily, step or signaling 8: the relay UE2 adds a mapping of the UE L2 IDs and local IDs of all currently allocated UEs in the UE-to-UE relay discovery response message.

[0139] Exemplarily, step or signaling 9: the relay UE1 sends a UE-to-UE relay discovery response message to the terminal UE1, which only includes the local ID allocated to the terminal UE1 and a mapping of the local ID of the target terminal UE2 and the UE L2 ID.

[0140] It should be noted that the steps of the above embodiments are merely examples and do not limit the scope of the present invention. Various modifications and variations can be made to the steps without departing from the spirit and scope of the present invention.

[0141] The order of the described steps (signaling / boxes) is not intended to be construed as a limitation, and any number of the described steps (signaling / boxes) may be skipped or combined in any order to implement a method or an alternative method.

[0142] The present disclosure describes examples of communication between terminal devices (such as remote UEs, such as source UE and target UE) and relay devices (such as relay UE) in the above embodiments, which are mainly for illustrative purposes and not restrictive.

[0143] The order of the steps (signaling / boxes) described is not intended to be interpreted as limiting, and any number of the steps (signaling / boxes) described can be skipped or combined in any order to implement a method or alternative method. Typically, any of the components, modules, methods, and operations described herein can be implemented using software, firmware, hardware (e.g., fixed logic circuitry), manual processing, or any combination thereof. Some operations of the example methods can be described in the general context of executable instructions stored on a computer-readable memory locally and / or remotely on a computer processing system, and implementation methods can include software applications, programs, functions, and the like. Alternatively or in addition, any function described herein can be performed, at least in part, by one or more hardware logic components, such as, but not limited to, a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), an application specific standard product (ASSP), a system on a chip (SoC), a complex programmable logic device (CPLD), and the like.

[0144] In addition, the signaling described in the embodiments of the present disclosure can be implemented in any manner known in the art. For example, the signaling can be explicit and / or implicit. In addition, the steps (signaling / frames) shown are for illustrative purposes only and are not intended to limit the present application.

[0145] Various aspects of the present invention may be understood from the following enumerated exemplary embodiments:

[0146] According to an example embodiment, a method for wireless communication between user equipment (UE) is provided, including: a second relay UE receiving a UE-to-UE relay discovery announcement message from a first relay UE; the second relay UE determining, based on the UE-to-UE relay discovery announcement message, whether to transmit a first message to a first remote UE connected to the second relay UE, wherein the first message is used by the second relay UE to reallocate a local ID to the first remote UE.

[0147] According to an example embodiment, the UE-to-UE relay discovery announcement message includes at least a first subset of a set of UE identifier (ID) mapping relationships associated with the first relay UE, the UE ID mapping relationship set including a mapping relationship between a UE Layer 2 identifier (L2 ID) and a local ID of each of a plurality of UEs connected to and / or discovered by the first relay UE, wherein the local ID of each of the plurality of UEs is uniquely assigned by the first relay UE, and wherein the first subset includes a mapping relationship between a local ID assigned by the first relay UE for a first remote UE to which the first relay UE is connected and the UE L2 ID of the first remote UE.

[0148] According to an example embodiment, the second relay UE determines whether to transmit a first message to a second remote UE connected to the second relay UE based on the UE-to-UE relay discovery announcement message, including: when the local ID of one of the multiple UEs connected and / or discovered by the first relay UE conflicts with the local ID assigned to the first remote UE by the second relay UE, transmitting the first message to the second remote UE.

[0149] According to an example embodiment, the method further includes: transmitting, by the second relay UE, the first message to the second remote UE; and receiving, by the second relay UE, a first response message from the second remote UE.

[0150] According to an example embodiment, the second relay UE is configured to perform any one of the example embodiments of the above method.

[0151] According to an example embodiment, a method for wireless communication between user equipment (UE) is provided, comprising: a first relay UE forwarding a UE-to-UE relay discovery request message to a second relay UE, wherein the second relay UE is located between the first relay UE and a first remote UE, and comprising: the first relay UE forwarding the UE-to-UE relay discovery request message together with at least a first subset of a set of UE identifier ID mapping relationships associated with the first relay UE to the second relay UE.

[0152] It can be understood that the first subset may also be applicable to other examples, other embodiments or other exemplary embodiments of the present disclosure, and the present disclosure is not intended to limit the first subset to the embodiments in which its text appears.

[0153] According to an example embodiment, the UE ID mapping relationship set includes a first mapping relationship between a UE Layer 2 identifier L2 ID and a local ID of each UE in a first plurality of UEs connected to and / or discovered by the first relay UE, the local ID of each UE in the first plurality of UEs being uniquely assigned by the first relay UE, and wherein the first subset includes a second mapping relationship between a UE Layer 2 identifier L2 ID and a local ID of a second remote UE requesting discovery.

[0154] According to an example embodiment, the method further includes: receiving, by the first relay UE, the UE-to-UE relay discovery request message from the second remote UE, wherein the UE-to-UE relay discovery request message includes the UE L2 IDs of the second remote UE and the first remote UE, respectively; receiving, by the first relay UE, a UE-to-UE relay discovery response message from the second relay UE; and forwarding, by the first relay UE, the UE-to-UE relay discovery response message to the second remote UE.

[0155] According to an example embodiment, the UE-to-UE relay discovery response message received by the first relay UE from the second relay UE is transmitted by the second relay UE upon determining that the first mapping relationship includes a UE L2 ID of a UE to which the second relay UE is connected.

[0156] According to an example embodiment, the relay discovery response message includes a second mapping relationship between a UE L2 ID of each UE in a second plurality of UEs linked to and / or discovered by the second relay UE and a local identifier (ID), wherein the local ID of each UE in the second plurality of UEs is uniquely assigned by the second relay UE, and the second plurality of UEs includes the first remote UE.

[0157] According to an example embodiment, forwarding the UE-to-UE relay discovery response message to the second remote UE by the first relay UE includes: allocating, by the first relay UE, a local ID to the second remote UE based on the second mapping relationship; and forwarding, by the first relay UE, the local ID allocated to the second remote UE and the first mapping relationship between the UE L2 ID of the first remote UE and the local ID, together with the UE-to-UE relay discovery response message, to the second remote UE.

[0158] According to an example embodiment, there is provided a first relay user equipment (UE), configured to perform any embodiment of the above method.

[0159] According to an example embodiment, a method for wireless communication between user equipments (UEs) is provided, including: a second relay UE receiving a UE-to-UE relay discovery request message from a first relay UE, wherein the UE-to-UE relay discovery request message includes a UE Layer 2 identifier (L2 ID) of each of a second remote UE and the first remote UE, and the first relay UE is located between the second remote UE and the second relay UE.

[0160] According to an example embodiment, the UE-to-UE relay discovery request message includes at least a first subset of a set of UE identifier (ID) mapping relationships associated with the first relay UE, the set of UE ID mapping relationships including a first mapping relationship between a UE L2 ID of each UE in a first plurality of UEs connected to and / or discovered by the first relay UE and a local identifier (ID), the local ID of each UE in the first plurality of UEs being uniquely assigned by the first relay UE, and wherein the first subset includes a mapping relationship between a local ID assigned by the first relay UE for a second remote UE to which the first relay UE is connected and the UE L2 ID of the second remote UE.

[0161] According to an example embodiment, the method further includes transmitting, by the second relay UE, a UE-to-UE relay discovery response message to the first relay UE, so that the first relay UE forwards the UE-to-UE relay discovery response message to the second remote UE.

[0162] According to an example embodiment, the method further includes: the second relay UE determining, based on the UE-to-UE relay discovery request message, whether to transmit the first message to the terminal UE connected to the second relay UE.

[0163] According to an example embodiment, the second relay UE determines whether to transmit a first message to a terminal UE connected to the second relay UE based on the UE-to-UE relay discovery request message, including: in response to an identification from the UE-to-UE relay discovery request message that there is a local ID that conflicts with the local ID assigned to the terminal UE by the second relay UE, determining to transmit a first message to the terminal UE, wherein the first message includes a new local ID assigned to the terminal UE by the second relay UE.

[0164] According to an example embodiment, the method further includes: transmitting, by the second relay UE, the first message to the terminal UE; and receiving, by the second relay UE, a first response message from the terminal UE.

[0165] According to an example embodiment, the above method further includes: the second relay UE finds the first remote UE based on the UE L2 ID of the first remote UE included in the relay discovery request message, and forwards the UE-to-UE relay discovery request message to the first remote UE; and the second relay UE receives a UE-to-UE relay discovery response message from the first remote UE.

[0166] According to an example embodiment, forwarding, by the second relay UE, the UE-to-UE relay discovery request message to the first remote UE includes: forwarding, by the second relay UE, the UE-to-UE relay discovery request message together with a second mapping relationship to the first remote UE.

[0167] According to an example embodiment, the second mapping relationship includes: a mapping relationship between a UE L2 ID of each of a second plurality of UEs to which the second relay UE has been connected and / or discovered before finding the first remote UE and a local identifier (ID), wherein the local ID of each of the second plurality of UEs is uniquely assigned by the second relay UE, and an additional mapping relationship between the UE L2 ID of the first remote UE and a local ID assigned to the first remote UE by the second relay UE based on the mapping relationship.

[0168] According to an example embodiment, transmitting, by the second relay UE, a UE-to-UE relay discovery response message to the first relay UE includes transmitting, by the second relay UE, the UE-to-UE relay discovery response message together with the second mapping relationship to the first relay UE.

[0169] According to an example embodiment, the first relay UE forwarding the UE-to-UE relay discovery response message to the second remote UE includes: the first relay UE assigning a local ID to the second remote UE based on the second mapping relationship received from the first relay UE; and the first relay UE forwarding the local ID assigned to the second remote UE and the additional mapping relationship together with the UE-to-UE relay discovery response message to the second remote UE.

[0170] According to an example embodiment, there is provided a second relay user equipment (UE), which is configured to perform any embodiment of the above method.

[0171] According to an example embodiment, a wireless communication method for a first relay user equipment (UE) is provided, comprising: the first relay UE transmitting a first response message to a connected first remote UE in response to receiving a first message from the first remote UE, wherein the first response message includes a local identifier (ID) allocated by the first relay UE to the first remote UE.

[0172] According to an example embodiment, the step further includes: the first relay UE transmitting a second message to a second relay UE, wherein the second message includes the local ID of the first remote UE.

[0173] According to an example embodiment, the second relay UE is connected to a second remote UE, and the second relay UE allocates the local ID to the second remote UE, and wherein the method further comprises: the first relay UE receiving a second response message from the second relay UE.

[0174] According to an example embodiment, in a case where the local ID allocated by the second relay UE to the second remote UE conflicts with the local ID allocated by the first relay UE to the first remote UE, the second response message includes the second relay UE reallocating the local ID to the first remote UE, and wherein the first response message transmitted by the first relay UE to the first remote UE includes the second relay UE reallocating the local ID to the first remote UE.

[0175] According to an example embodiment, a third relay UE is further included between the first relay UE and the second relay UE, and wherein the first relay UE transmitting the second message to the second relay UE includes: the first relay UE transmitting the second message to the third relay UE, so that the third relay UE adds all local IDs allocated by the third relay UE to the second message, and transmits the resulting message to the second relay UE.

[0176] According to an example embodiment, the method further includes: the first relay UE receiving a third message from the first remote UE, wherein the third message includes a UE Layer 2 identifier (L2 ID) of a second remote UE sent by the first remote UE to the first relay UE and used for the first remote UE requesting to communicate with it.

[0177] According to an example embodiment, the method further includes: the first relay UE transmitting a fourth message to the second relay UE in response to receiving a discovery message broadcast by a second relay UE among the plurality of relay UEs, wherein the second relay UE is connected to the second remote UE, and the second relay UE has allocated the local ID for the second remote UE, and the discovery message includes the UE L2 ID of the second remote UE, and wherein the fourth message includes all local IDs allocated by the first relay UE and the UE L2 ID of the second remote UE.

[0178] According to an example embodiment, the method further includes: the first relay UE receiving a fourth response message from the second relay UE, and forwarding the fourth response message to the first remote UE.

[0179] According to an example embodiment, in a case where the allocated local ID of the second remote UE conflicts with the local ID allocated by the first relay UE to the first remote UE, the fourth response message includes the second relay UE reallocating the local ID to the second remote UE, and wherein the fourth response message received by the first relay UE from the second relay UE includes the second relay UE reallocating the local ID to the second remote UE.

[0180] According to an example embodiment, there is provided a first relay user equipment (UE), configured to perform any embodiment of the above method.

[0181] FIG11 is a block diagram of an example system 700 for wireless communication according to an embodiment of the present disclosure. The embodiments described herein can be implemented into a system using any appropriately configured hardware and / or software. FIG11 illustrates system 700, including radio frequency (RF) circuitry 710, baseband circuitry 720, processing unit 730, memory / storage 740, display 750, camera 760, sensor 770, and input / output (I / O) interface 780, coupled to one another as shown.

[0182] The processing unit 730 may include circuits, such as, but not limited to, one or more single-core or multi-core processors. The processor may include any combination of general-purpose processors and special-purpose processors, such as a graphics processor and an application processor. The processor may be coupled to a memory / storage and configured to execute instructions stored in the memory / storage to enable various applications and / or operating systems running on the system. The RF circuit 710, baseband circuit 720, processing unit 730, memory / storage 740, display 750, camera 760, sensor 770, and I / O interface 780 are well-known components of the system 700, such as, but not limited to, laptop computing devices, tablet computing devices, netbooks, ultrabooks, smartphones, etc. In addition, instructions as a software product may be stored in a computer-readable storage medium. The software product in the computer is stored in a storage medium and includes multiple commands for a computing device (such as a personal computer, server, or network device) to execute all or some of the steps disclosed in the embodiments of the present disclosure. The storage medium includes a USB disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a floppy disk, or other types of media capable of storing program codes.

[0183] The embodiments of the present disclosure are a combination of techniques / processes that may be employed in 3GPP specifications to create a final product.

[0184] While the present disclosure has been described in connection with what is considered to be the most practical and preferred embodiment, it is to be understood that the disclosure is not limited to the disclosed embodiment, but is intended to cover various arrangements embodied within the broadest interpretation of the appended claims.

Claims

1. A wireless communication method between user equipment (UE), comprising: The second relay UE receives a UE-to-UE relay discovery announcement message from the first relay UE; The second relay UE determines whether to transmit a first message to a first remote UE connected to the second relay UE based on the UE-to-UE relay discovery announcement message, wherein the first message is used by the second relay UE to reallocate a local ID to the first remote UE.

2. The method according to claim 1, wherein: The UE-to-UE relay discovery announcement message includes at least a first subset of a set of UE identifier (ID) mapping relationships associated with the first relay UE, the UE ID mapping relationship set including a mapping relationship between a UE Layer2 identifier (L2 ID) and a local ID of each of a plurality of UEs connected and / or discovered by the first relay UE, wherein the local ID of each of the plurality of UEs is uniquely assigned by the first relay UE, and wherein the first subset includes a mapping relationship between a local ID assigned by the first relay UE to a first remote UE to which the first relay UE is connected and the UE L2 ID of the first remote UE.

3. The method according to claim 2, wherein: The second relay UE determining whether to transmit a first message to a second remote UE connected to the second relay UE based on the UE-to-UE relay discovery announcement message comprises: When the local ID of one of the plurality of UEs connected and / or discovered by the first relay UE conflicts with the local ID allocated by the second relay UE to the first remote UE, a first message is transmitted to the second remote UE.

4. The method according to claim 3, further comprising: transmitting, by the second relay UE, the first message to the second remote UE; A first response message is received by the second relay UE from the second remote UE.

5. A second relay user equipment (UE), the second relay UE being configured to perform the method according to any one of claims 1 to 4.

6. A wireless communication method between user equipment (UE), comprising: The first relay UE forwards the UE-to-UE relay discovery request message to a second relay UE, where the second relay UE is located between the first relay UE and the first remote UE, including: The first relay UE forwards the UE-to-UE relay discovery request message together with at least a first subset of a UE identifier ID mapping relationship set associated with the first relay UE to the second relay UE.

7. The method according to claim 6, in, The UE ID mapping relationship set includes a first mapping relationship between a UE Layer 2 identifier L2 ID of each UE in a first plurality of UEs connected and / or discovered by the first relay UE and a local ID, wherein the local ID of each UE in the first plurality of UEs is uniquely assigned by the first relay UE, and The first subset includes a second mapping relationship between a UE Layer 2 identifier L2 ID of a second remote UE requested to be discovered and a local ID.

8. The method according to claim 6 or 7, further comprising: The first relay UE receives the UE-to-UE relay discovery request message from the second remote UE, wherein the UE-to-UE relay discovery request message includes the UE L2 IDs of the second remote UE and the first remote UE, respectively; receiving, by the first relay UE, a UE-to-UE relay discovery response message from the second relay UE; and forwarding, by the first relay UE, the UE-to-UE relay discovery response message to the second remote UE, 9. The method according to claim 8, wherein: The UE-to-UE relay discovery response message received by the first relay UE from the second relay UE is transmitted by the second relay UE upon determining that the first mapping relationship includes the UE L2 ID of the UE to which the second relay UE is connected.

10. The method according to any one of claims 6 to 8, wherein: The relay discovery response message includes a second mapping relationship between a UE L2 ID of each UE in a second plurality of UEs linked to and / or discovered by the second relay UE and a local identifier (ID), wherein the local ID of each UE in the second plurality of UEs is uniquely assigned by the second relay UE, and the second plurality of UEs includes the first remote UE.

11. The method according to claim 10, wherein: Forwarding, by the first relay UE, the UE-to-UE relay discovery response message to the second remote UE includes: Allocating, by the first relay UE, a local ID for the second remote UE based on the second mapping relationship; The local ID allocated to the second remote UE and a first mapping relationship between the UE L2 ID of the first remote UE and the local ID are forwarded by the first relay UE to the second remote UE together with the UE-to-UE relay discovery response message.

12. A first relay user equipment (UE), the first relay UE being configured to perform the method according to any one of claims 6 to 9.

13. A method for wireless communication between user equipment (UE), comprising: The second relay UE receives a UE-to-UE relay discovery request message from the first relay UE, The UE-to-UE relay discovery request message includes respective UE Layer 2 identifiers (L2 IDs) of the second remote UE and the first remote UE, and the first relay UE is located between the second remote UE and the second relay UE.

14. The method according to claim 13, in, The UE-to-UE relay discovery request message includes at least a first subset of a set of UE identifier (ID) mapping relationships associated with the first relay UE, the set of UE ID mapping relationships including a first mapping relationship between a UE L2 ID of each UE in a first plurality of UEs connected and / or discovered by the first relay UE and a local identifier (ID), the local ID of each UE in the first plurality of UEs being uniquely assigned by the first relay UE, and The first subset includes a mapping relationship between a local ID allocated by the first relay UE to a second remote UE connected to the first relay UE and a UE L2 ID of the second remote UE.

15. The method according to claim 13 or 14, further comprising transmitting, by the second relay UE, a UE-to-UE relay discovery response message to the first relay UE, so that the first relay UE forwards the UE-to-UE relay discovery response message to the second remote UE.

16. The method according to any one of claims 13 to 15, further comprising: The second relay UE determines whether to transmit a first message to a terminal UE connected to the second relay UE based on the UE-to-UE relay discovery request message.

17. The method according to claim 16, wherein: The second relay UE determining whether to transmit a first message to a terminal UE connected to the second relay UE based on the UE-to-UE relay discovery request message includes: In response to a discovery request message from the UE to UE relay identifying a local ID that conflicts with the local ID assigned to the terminal UE by the second relay UE, it is determined that a first message is to be transmitted to the terminal UE, wherein the first message includes a new local ID assigned to the terminal UE by the second relay UE.

18. The method according to claim 16, further comprising: The second relay UE transmits the first message to the terminal UE; The second relay UE receives a first response message from the terminal UE.

19. The method according to any one of claims 13 to 18, further comprising: The second relay UE finds the first remote UE based on the UE L2 ID of the first remote UE included in the relay discovery request message, and forwards the UE-to-UE relay discovery request message to the first remote UE; A UE-to-UE relay discovery response message is received by the second relay UE from the first remote UE.

20. The method according to claim 19, wherein: Forwarding, by the second relay UE, the UE-to-UE relay discovery request message to the first remote UE includes: The second relay UE forwards the UE-to-UE relay discovery request message to the first remote UE.

21. The method according to claim 20, wherein: The second mapping relationship includes: a mapping relationship between a UE L2 ID and a local identifier (ID) of each UE in a second plurality of UEs that the second relay UE has connected to and / or discovered before finding the first remote UE, wherein the local ID of each UE in the second plurality of UEs is uniquely assigned by the second relay UE, and An additional mapping relationship between the UE L2 ID of the first remote UE and a local ID allocated by the second relay UE to the first remote UE based on the mapping relationship.

22. The method according to claim 20, wherein: Transmitting, by the second relay UE, a UE-to-UE relay discovery response message to the first relay UE includes: The second relay UE transmits the UE-to-UE relay discovery response message together with the second mapping relationship to the first relay UE.

23. The method according to claim 21, wherein: The first relay UE forwarding the UE-to-UE relay discovery response message to the second remote UE includes: Allocating, by the first relay UE, a local ID for the second remote UE based on the second mapping relationship received from the first relay UE; The first relay UE forwards the local ID allocated to the second remote UE and the additional mapping relationship together with the UE-to-UE relay discovery response message to the second remote UE.

24. A second relay User Equipment (UE), the second relay UE being configured to perform the method according to any one of claims 11 to 20.

25. A wireless communication method for a first relay user equipment (UE), comprising: The first relay UE transmits a first response message to the first remote UE in response to receiving a first message from the connected first remote UE, The first response message includes a local identifier (ID) allocated by the first relay UE to the first remote UE.

26. The method according to claim 25, further comprising: The first relay UE transmits a second message to the second relay UE, The second message includes a mapping relationship between the local ID and UE L2 ID of the first remote UE.

27. The method according to claim 25, wherein: The second relay UE is connected to a second remote UE, and the second relay UE allocates the local ID to the second remote UE, and wherein the method further comprises: The first relay UE receives a second response message from the second relay UE.

28. The method according to claim 26, wherein: In a case where the local ID allocated by the second relay UE to the second remote UE conflicts with the local ID allocated by the first relay UE to the first remote UE, the second response message includes the second relay UE reallocating the local ID to the first remote UE, and wherein the first response message transmitted by the first relay UE to the first remote UE includes the second relay UE reallocating the local ID to the first remote UE.

29. The method according to any one of claims 25 to 27, wherein: A third relay UE is also included between the first relay UE and the second relay UE, and wherein the first relay UE transmitting the second message to the second relay UE includes: The first relay UE transmits the second message to the third relay UE, so that the third relay UE adds all local IDs allocated by the third relay UE to the second message and transmits the obtained message to the second relay UE.

30. The method of claim 25, further comprising: The first relay UE receives a third message from the first remote UE, wherein the third message includes a UE Layer 2 identifier (L2 ID) of a second remote UE that the first remote UE sends to the first relay UE and is used for the first remote UE to communicate with.

31. The method of claim 29, further comprising: The first relay UE transmits a fourth message to the second relay UE in response to receiving a discovery message broadcast by a second relay UE among the plurality of relay UEs, wherein the second relay UE is connected to the second remote UE, and the second relay UE has allocated the local ID to the second remote UE, and the discovery message includes the UE L2 ID of the second remote UE, and The fourth message includes all local IDs allocated by the first relay UE and the UE L2 ID of the second remote UE.

32. The method of claim 30, further comprising: The first relay UE receives a fourth response message from the second relay UE, and forwards the fourth response message to the first remote UE.

33. The method according to claim 31, wherein: In a case where the assigned local ID of the second remote UE conflicts with the local ID assigned by the first relay UE to the first remote UE, the fourth response message includes the second relay UE reallocating the local ID to the second remote UE, and wherein the fourth response message received by the first relay UE from the second relay UE includes the second relay UE reallocating the local ID to the second remote UE.

34. A first relay User Equipment (UE) configured to perform the method according to any one of claims 22 to 30.

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