Side link communication device and method thereof

Abstract

A method performed by a relay UE is provided. The relay UE establishes a first RLC channel between a first remote UE and the relay UE, wherein the first RLC channel is associated with a first end-to-end identifier. The relay UE establishes a second RLC channel between a second remote UE and the relay UE, wherein the second RLC channel is associated with the first end-to-end identifier or the second end-to-end identifier. The relay UE receives an incoming sidelink transmission from the first remote UE on the first RLC channel, wherein the incoming sidelink transmission includes the first end-to-end identifier. The relay UE sends an outgoing sidelink transmission to the second remote UE on the second RLC channel, wherein the outgoing sidelink transmission includes one of the first end-to-end identifier and the second end-to-end identifier.

Description

Technical Field

[0001] The present application generally relates to mobile communications, and, more specifically, to an apparatus and method for sidelink (SL) communications in a user equipment (UE) to user equipment relay architecture. Background Art

[0002] In a typical mobile communication environment, a UE (also called a mobile station (MS)) with wireless communication capabilities, such as a mobile phone (also called a cellular phone or cell phone) or a tablet personal computer (PC), can send voice and / or data signals to one or more cellular networks. Wireless communication between UE and cellular network can be performed using various radio access technologies (RAT), such as Global System for Mobile communication (GSM) technology, General Packet Radio Service (GPRS) technology, Enhanced Data rates for Global Evolution (EDGE) technology, Wideband Code Division Multiple Access (WCDMA) technology, Code Division Multiple Access 2000 (CDMA-2000) technology, Time Division-Synchronous Code Division Multiple Access (TD-SCDMA) technology, Worldwide Interoperability for Microwave Access (WiMAX) technology, Long Term Evolution (LTE) technology and advanced LTE (LTE-Advanced, LTE-A) technology, etc.

[0003] These RAT technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate at municipal, national, regional and even global levels. An example of an emerging telecommunication standard is 5G New Radio (NR). 5G NR is an enhancement set to the LTE mobile standard released by the Third Generation Partnership Project (3GPP). It is designed to better support mobile broadband Internet access by improving spectrum efficiency, reducing costs and improving services.

[0004] In LTE and 5G NR networks, device-to-device (D2D) communication is supported to allow two or more UEs to communicate directly with each other. This D2D communication can also be called SideLink (SL) communication, which can be applied to vehicle-to-everything (V2X) services. V2X refers to communication technologies that are carried out using all interfaces of the vehicle, including vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), vehicle-to-person (V2P), and vehicle-to-network (V2N). Specifically, in some cases, two UEs may have data to exchange, but they may not be able to communicate directly with each other due to physical distance or obstacles. In order to use in this case, a UE-to-UE relay design is considered, in which a relay UE can be used to forward data between two or more remote UEs.

[0005] In a layer 2 UE-to-UE relay architecture, data is transferred from one remote UE (UE 1) to another remote UE (UE2) via an intermediate relay UE using a protocol stack, wherein the upper layers of the protocol stack (e.g., Service Data Adaptation Protocol (SDAP) layer and Packet Data Convergence Protocol (PDCP) layer) are end-to-end (i.e., terminated between remote UEs), while the lower layers (e.g., Radio Link Control (RLC) layer, Media Access Control (MAC) layer and Physical (PHY) layer) are hop-by-hop (i.e., terminated between each remote UE and relay UE). This means that the remote UE exchanges data with the relay UE through one or more channels (e.g., RLC channels) managed in the lower layer, and they exchange data with another remote UE through one or more bearers (e.g., SL Radio Bearer (SLRB)) managed in the upper layer. In order to correctly route data from a source remote UE to a target remote UE, the relay UE needs to know the relationship between the upper layer bearer (or the path that the bearer takes through the relay system) and the lower layer channel, so that the relay UE can map incoming transmissions (e.g., data packets received from the remote UE on the ingress RLC channel) to outgoing transmissions (e.g., data packets sent to the remote UE on the egress RLC channel). In order to make this mapping unambiguous, the identifier used for the upper layer bearer / path should be unique within the scope of the relay UE. Therefore, it is very necessary for the relay UE and the remote UE to have a coordinated way to allocate and manage identifiers for end-to-end communication. Summary of the invention

[0006] In a first aspect of the present application, a method performed by a relay UE is provided. The method comprises the following steps: establishing a first radio link control (RLC) channel between a first remote UE and a relay UE, wherein the first RLC channel is associated with a first end-to-end identifier; establishing a second RLC channel between a second remote UE and a relay UE, wherein the second RLC channel is associated with the first end-to-end identifier or the second end-to-end identifier; receiving an incoming side link transmission from the first remote UE on the first RLC channel, wherein the incoming side link transmission includes the first end-to-end identifier; and sending an outgoing side link transmission to the second remote UE on the second RLC channel, wherein the outgoing side link transmission includes one of the first end-to-end identifier and the second end-to-end identifier.

[0007] In an implementation form of the first aspect of the present application, the outgoing sidelink transmission includes a first end-to-end identifier in response to the second RLC channel being associated with the first end-to-end identifier. The method further includes the following steps: determining a mapping of the first RLC channel to the second RLC channel for the outgoing sidelink transmission based on the first end-to-end identifier.

[0008] In another implementation form of the first aspect of the present application, the outgoing side link transmission includes a second end-to-end identifier in response to the second RLC channel being associated with the second end-to-end identifier. The method also includes the following steps: determining a mapping of the first RLC channel to the second RLC channel for outgoing SL transmission based on the first end-to-end identifier. The first end-to-end identifier may include an SL Radio Bearer (SLRB) ID and information of the second remote UE, and the second end-to-end identifier may include an SLRB ID and information of the first remote UE. For example, the information of the first remote UE may include a first UE ID of the first remote UE, and the information of the second remote UE may include a second UE ID of the second remote UE.

[0009] In another implementation form of the first aspect of the present application, a first RLC channel between a first remote UE and a relay UE is established by: receiving a first reconfiguration message from the first remote UE; and sending a first reconfiguration complete message to the first remote UE. The first end-to-end identifier is indicated in the first reconfiguration message or the first reconfiguration complete message.

[0010] In another implementation form of the first aspect of the present application, a second RLC channel between a second remote UE and a relay UE is established by: sending a second reconfiguration message to the second remote UE; and receiving a second reconfiguration complete message from the second remote UE. Indicating the first end-to-end identifier in the second reconfiguration complete message in response to the second RLC channel being associated with the first end-to-end identifier, or indicating the second end-to-end identifier in the second reconfiguration complete message in response to the second RLC channel being associated with the second end-to-end identifier. Alternatively, indicating the first end-to-end identifier in the second reconfiguration message in response to the second RLC channel being associated with the first end-to-end identifier, or indicating the second end-to-end identifier in the second reconfiguration message in response to the second RLC channel being associated with the second end-to-end identifier.

[0011] In a second aspect of the present application, a method performed by a first remote UE is provided. The method comprises the following steps: establishing an RLC channel between the first remote UE and a relay UE, wherein the RLC channel is associated with an end-to-end identifier; after the RLC channel is established, establishing an SLRB between the first remote UE and a second remote UE, wherein the SLRB is associated with the end-to-end identifier; and after the SLRB is established, sending an SL transmission for the second remote UE on the RLC channel, wherein the SL transmission includes the end-to-end identifier.

[0012] In an implementation form of the second aspect of the present application, an RLC channel between a first remote UE and a relay UE is established by: sending a first reconfiguration message to the relay UE; and receiving a first reconfiguration complete message from the relay UE. The first remote UE may determine an end-to-end identifier, and indicate the end-to-end identifier in the first reconfiguration message. Alternatively, the end-to-end identifier may be indicated in the first reconfiguration complete message.

[0013] In another implementation form of the second aspect of the present application, the SLRB between the first remote UE and the second remote UE is established in the following manner: sending a second reconfiguration message to the second remote UE via the relay UE; and receiving a second reconfiguration completion message from the second remote UE via the relay UE.

[0014] In another implementation form of the second aspect of the present application, the end-to-end identifier includes the SLRB ID and information of the second remote UE. For example, the information of the second remote UE includes the UE ID of the second remote UE.

[0015] The present invention proposes a side link communication device and method thereof, and achieves the beneficial effect of improving the transmission service quality by using an end-to-end identifier.

[0016] Other aspects and features of the present application will become apparent to those skilled in the art upon reading the following description of specific embodiments of the method for SL communication in a UE-to-UE relay architecture. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present application may be more fully understood by reading the following detailed description and examples with reference to the accompanying drawings, in which:

[0018] Figure 1 is a block diagram illustrating an exemplary user plane protocol stack for a layer 2 UE-to-UE relay architecture according to an embodiment of the present application;

[0019] Figure 2 is a block diagram of a UE according to an embodiment of the present application;

[0020] Figure 3is a schematic diagram showing the relationship between SLRB and RLC channels in an exemplary layer 2 UE-to-UE relay architecture;

[0021] Figure 4 It shows that according to Figure 3 A schematic diagram of mapping SLRB to RLC channel of an embodiment;

[0022] Figure 5 is a message sequence chart illustrating a connection establishment process in a UE-to-UE relay architecture according to an embodiment of the present application;

[0023] Figure 6 is a message sequence chart illustrating the establishment of an RLC channel and an SLRB in a UE-to-UE relay architecture according to an embodiment of the present application;

[0024] Figure 7 is a flowchart showing a method for relaying UE supporting SL communication in a UE-to-UE relay architecture according to an embodiment of the present application; and

[0025] Figure 8 It is a flowchart of a method for supporting SL communication for a first remote UE in a UE-to-UE relay architecture according to an embodiment of the present application. DETAILED DESCRIPTION

[0026] The purpose of the following description is to illustrate the basic principle of the present application and should not be considered as having a limiting meaning. It should be understood that the embodiment can be implemented with software, hardware, firmware or any combination thereof. The terms "comprise", "include", "include" and / or "include", when used in this article, specify the existence of the features, integers, steps, operations, elements and / or components, but do not exclude the existence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0027] Figure 1 is a block diagram illustrating an exemplary user plane protocol stack for a layer 2 UE-to-UE relay architecture according to an embodiment of the present application.

[0028] like Figure 1 As shown, the user plane protocol stack for the remote UE may include an SDAP layer, a PDCP layer, an adaptation layer, an RLC layer, a MAC layer, and a physical (PHY) layer. All of these layers except the adaptation layer can be modeled in those layers that have been developed for SL communications in the 3GPP specification version 16. The adaptation layer is dedicated to the relay environment and has the function of mapping upper layer bearers to lower layer channels in a manner that supports forwarding through a relay UE. Specifically, the SDAP and PDCP layers are end-to-end (i.e., terminated between remote UEs), while the adaptation layer, RLC, MAC, and PHY layers are hop-by-hop (i.e., terminated between a remote UE and a relay UE).

[0029] It should be understood that Figure 1 The protocol stacks shown in are for illustrative purposes only and are not intended to limit the scope of the present application. The protocol stacks may be replicated across different sets of UEs, so that, for example, a single relay UE may have multiple peer remote UEs in any combination corresponding to each other. In one example, remote UE 1 may communicate with both remote UE 2 and remote UE 3 via the same relay UE. In this case, UE 1 and UE 2 will instantiate a first set of protocol stacks, while UE 1 and UE 3 will instantiate a second set of protocol stacks.

[0030] Although not shown, the control plane protocol stack for the UE-to-UE relay architecture may be similar, except that the SDAP layer should be omitted and a control protocol layer (eg, PC5 Radio Resource Control (PC5-RRC) layer) should be added above the PDCP layer.

[0031] In a Layer 2 UE-to-UE relay architecture, there are two different levels of "bearer" or "channel" constructions, where "channel" may refer to an RLC channel managed by the RLC layer and used to connect a remote UE and a relay UE, and "bearer" may refer to an SLRB managed by the PDCP layer and used to connect a remote UE and another remote UE.

[0032] Figure 2 is a block diagram of a UE according to an embodiment of the present application.

[0033] In an embodiment, the UE may refer to a relay UE or a remote UE (ie, a sending remote UE or a receiving remote UE in a UE-to-UE relay architecture).

[0034] like Figure 2 As shown, the UE may include a wireless transceiver 10 , a controller 20 , a storage device 30 , a display device 40 , and an input / output (I / O) device 50 .

[0035] The wireless transceiver 10 may be configured to perform wireless transmission and reception to other UEs and / or a base station (BS) in a cellular network (e.g., a 5G NR network) and from the UE and / or the BS.

[0036] Specifically, the wireless transceiver 10 may include a baseband processing device 11, a radio frequency (RF) device 12, and an antenna 13. The antenna 13 may include an antenna array for beamforming.

[0037] The baseband processing device 11 is configured to perform baseband signal processing and control communication between a subscriber identification card (not shown) and the RF device 12. The baseband processing device 11 may include a plurality of hardware components to perform baseband signal processing, including analog-to-digital conversion (ADC) / digital-to-analog conversion (DAC), gain adjustment, modulation / demodulation, encoding / decoding, and the like.

[0038] The RF device 12 may receive an RF wireless signal via an antenna 13, convert the received RF wireless signal into a baseband signal, which is processed by the baseband processing device 11, or the RF device 12 may receive a baseband signal from the baseband processing device 11, convert the received baseband signal into an RF wireless signal, and then transmit it via the antenna 13. The RF device 12 may also include a plurality of hardware devices to perform radio frequency conversion. For example, the RF device 12 may include a mixer for multiplying a baseband signal with a carrier oscillating in a radio frequency in the supported RAT, where the radio frequency may be any radio frequency used in 5G NR technology (e.g., millimeter wave 30 GHz to 300 GHz), 900 MHz, 2100 MHz, or 2.6 GHz used in LTE / LTE-A / TD-LTE technology, or other radio frequencies, depending on the RAT used.

[0039] The controller 20 may be a general-purpose processor, a micro control unit (MCU), an application processor, a digital signal processor (DSP), a graphics processing unit (GPU), a holographic processing unit (HPU), a neural processing unit (NPU), etc., and includes various circuits that provide the following functions: data processing and calculation, controlling the wireless transceiver 10 to wirelessly communicate with other UEs and / or BSs, storing data (e.g., program code) in the storage device 30 and retrieving data (e.g., program code) from the storage device 30, sending a series of frame data (e.g., represented as text messages, graphics, images, etc.) to the display device 40, and receiving user input signals or output signals via the I / O device 50.

[0040] Specifically, the controller 20 may coordinate the above operations of the wireless transceiver 10 , the storage device 30 , the display device 40 , and the I / O device 50 to perform the method of SL communication in a UE-to-UE relay architecture.

[0041] In another embodiment, the controller 20 may be incorporated into the baseband processing device 11 to function as a baseband processor.

[0042] As will be appreciated by those skilled in the art, the circuitry of the controller 20 will typically include transistors configured in a manner to control the operation of the circuitry in accordance with the functions and operations described herein. It will be further appreciated that the specific structure or interconnection of the transistors will typically be determined by a compiler, such as a register transfer language (RTL) compiler. The RTL compiler can be operated by a processor on a script that is very similar to assembly language code to compile the script into a form used for the layout or manufacture of the final circuit. In fact, RTL is well known for its role and use in facilitating the design process of electronic and digital systems.

[0043] The storage device 30 may be a non-transitory machine-readable storage medium, including a memory (e.g., flash memory or non-volatile random access memory (NVRAM)), a magnetic storage device (e.g., a hard disk or a tape), an optical disk, or any combination thereof, for storing Figure 1 Instructions and / or program codes for the applications, communication protocols (e.g., a communication protocol for communicating with the 5G NR network 120), and / or methods for SL communications in a UE-to-UE relay architecture are shown.

[0044] The display device 40 may be a liquid crystal display (LCD), a light-emitting diode (LED) display, or an electronic paper display (EPD), etc., for providing a display function. Alternatively, the display device 40 may also include one or more touch sensors disposed thereon or therebelow for sensing contact, connection, or proximity of an object (e.g., a finger or a stylus).

[0045] The I / O device 50 may include one or more buttons, keyboards, mice, touch pads, cameras, microphones and / or speakers, etc., to serve as a man-machine interface (MMI) for interacting with a user.

[0046] It should be understood that Figure 2The components described in the embodiments are for illustrative purposes only and are not intended to limit the scope of the present application. For example, the UE may include more components, such as a power supply and / or a global positioning system (GPS) device, where the power supply may be a mobile / replaceable battery that provides power to all other components of the UE, and the GPS device may provide location information of the UE for use by some location-based services or applications. Alternatively, the UE may include fewer components. For example, the UE may not include a display device 40 and / or an I / O device 50.

[0047] Figure 3 is a schematic diagram showing the relationship between SLRB and RLC channels in an exemplary Layer 2 UE-to-UE relay architecture.

[0048] like Figure 3 As shown, there are three remote UEs and one relay UE serving these remote UEs. Specifically, remote UE1 and remote UE 2 communicate with each other on a single SLRB (in Figure 3 , and remote UE 1 and remote UE 3 communicate with each other on three different SLRBs (in Figure 3 Although these SLRBs are shown as directly connecting remote UEs to each other, it should be understood that the actual data transfer on these end-to-end bearers is through the relay UE.

[0049] In addition, the relay UE and these remote UEs communicate based on various RLC channels. For example, the remote UE 1 and the relay UE communicate on two RLC channels (in Figure 3 W(1, R) and X(1, R) in FIG. 2 ), the remote UE 2 and the relay UE communicate on a single RLC channel (in Figure 3 denoted as V(2, R)), and the remote UE 3 and the relay UE communicate on two RLC channels (in Figure 3 Represented as Y(3,R) and Z(3,R)).

[0050] Figure 3 In the embodiment of the present invention, the mapping of SLRB to RLC channel can be further described as follows: Figure 4 As shown. Figure 4As shown, SLRB D (1, 2) is mapped to RLC channels W (1, R) and V (2, R); SLRB A (1, 3) is mapped to RLC channels W (1, R) and Y (3, R); SLRB B (1, 3) is mapped to RLC channels X (1, ​​R) and Y (3, R); SLRB C (1, 3) is mapped to RLC channels X (1, ​​R) and Z (3, R).

[0051] It should be noted that SLRBs do not necessarily have globally unique IDs. That is, it is not assumed that the identifiers A / B / C / D correspond directly to any distinguishing values ​​known to all UEs. According to the 3GPP specifications for SL communications, each remote UE has a set of identifiers for its bearers with a given peer, (for the receiving UE, these identifiers are given by the information element SLRB-PC5-ConfigIndex in the RRCReconfigurationSidelink message when the bearer is set up), but the indexes of these identifiers may conflict for different UEs. For example, in Figures 3-4 In the scenario of , remote UE 2 may have index 1 associated with SLRB D, while remote UE 3 may have index 1 associated with SLRB A. Now consider a packet arriving from remote UE 1 to the relay UE on the ingress RLC channel W(1, R). Figure 4 In the mapping scenario, the packet may be associated with SLRB D or SLRB A. In order to forward the packet to the correct recipient on the correct egress RLC channel, the relay UE must determine which SLRB is involved. However, since logical channels only correspond to RLC channels mapped by multiple SLRBs, the relay UE cannot make a determination based solely on the SL logical channel ID (LCID).

[0052] In one novel aspect of the present application, an end-to-end identifier is indicated to the relay UE together with each packet, wherein the end-to-end identifier specifically refers to information that can help the relay UE eliminate routing ambiguity of packets received on a specific RLC channel.

[0053] To further clarify, the end-to-end identifier may be negotiated between the relay UE and the remote UE when establishing the RLC channel and / or SLRB. The end-to-end identifier may be indicated in the adaptation layer, for example, as part of an adaptation layer header or subheader associated with the data packet. Alternatively, since layers below the adaptation layer are processed in the relay UE when the packet is received, the end-to-end identifier may be indicated in any underlying layer, for example, the SL LCID is indicated at the MAC layer.

[0054] For example, if the end-to-end identifier is indicated in the MAC layer, it can be understood as an extension to the LCID space. In this case, the sending remote UE can indicate the SL LCID and the "Extended LCID" corresponding to the specific RLC channel pair at the MAC layer (e.g., in the MAC subheader). Figure 4 In the scenario of , one extended LCID may be assigned to the pair of RLC channel W (ingress) and RLC channel V (egress), and another extended LCID may be assigned to the pair of RLC channel W (ingress) and RLC channel Y (egress). The relay UE may process the extended LCID to determine the egress RLC channel.

[0055] In addition, the end-to-end identifier may also need to be provided to the receiving remote UE. Figure 4 In the scenario of FIG. 3 , consider a packet arriving at remote UE 3 on RLC channel Y. Remote UE 3 needs to determine whether the packet it is receiving is for SLRB A or SLRB B. Because each LCID corresponds to an RLC channel, and the relevant RLC channel (i.e., RLC channel Y) has two SLRBs mapped to it, knowing the LCID does not provide sufficient information. Therefore, it may be necessary for the relay UE to transmit the end-to-end identifier along with the data packet to the receiving remote UE.

[0056] In one embodiment, the end-to-end identifier may be a combination of the SLRB ID and information of the sending remote UE and / or the receiving remote UE (e.g., Layer 2 UE ID, MAC address). Figure 4 In the scenario, an end-to-end identifier may be individually assigned for each RLC channel, so that a packet arriving at the relay UE on SLRB D of RLC channel W may be accompanied by an end-to-end identifier value that is different from the end-to-end identifier value of the same packet sent by the relay UE on SLRB D of RLC channel V. For example, remote UE 1 may send a packet with an end-to-end identifier on RLC channel W, wherein the end-to-end identifier includes an SLRB ID (e.g., SLRB D) and a UE ID of a receiving remote UE (e.g., remote UE 2), and the relay UE may determine that the outgoing RLC channel is RLC channel V based on the end-to-end identifier, and replace the UE ID in the end-to-end identifier with the UE ID of the sending remote UE (i.e., remote UE 1) before forwarding the packet with the end-to-end identifier.

[0057] In another embodiment, the end-to-end identifier may be a path identifier maintained at the relay UE, which path identifier corresponds to a specific pair of RLC channels and thus represents the transmission path between the two remote UEs. That is, the end-to-end identifier may be common across the entire transmission path. For example, in Figure 4 In the scenario, packets sent on SLRB D on RLC channel W (for transmission from remote UE 1 to relay UE) and RLC channel V (for transmission from relay UE to remote UE 2) may be assigned the same end-to-end identifier. The transmission path may be determined before or when the SLRB is established (by the relay UE, or negotiated by the relay UE and one or more remote UEs), and a path ID (which must be unique at the relay UE) may be assigned to reflect the applicable RLC channel. Thus, a path ID will be associated with the SLRB when the SLRB is established, and each packet transmitted on the SLRB will be accompanied by a corresponding path ID included in a protocol layer (e.g., adaptation layer) visible to the relay UE. For example, the UE initiating the SLRB establishment (e.g., the remote UE) may indicate the corresponding path ID in an RRCReconfigurationSidelink message to establish one or more RLC channels carrying the SLRB, or the responding UE (e.g., the relay UE) may indicate the path ID in an RRCReconfigurationCompleteSidelink message confirming the establishment of one or more RLC channels carrying the SLRB. It should be noted that, unlike the design used in the Integrated Access and Backhaul (IAB) following release 16 of the 3GPP specification, in which the destination and path IDs are included in the header of the Backhaul Adaptation Protocol (BAP) Protocol Data Unit (PDU), the end-to-end identifier used in the present application only needs to include the path ID, which is sufficient for the relay UE to determine the egress RLC channel to allow the relay UE to forward the packet to the correct destination UE.

[0058] Figure 5 It is a message sequence diagram showing the connection establishment process in the UE-to-UE relay architecture according to an embodiment of the present application.

[0059] In the UE-to-UE relay architecture, the connection establishment process can be initiated by a remote UE that wants to send data to another remote UE. In an embodiment, it is the remote UE 1 that initiates the connection establishment process because it wants to send data to the remote UE 2.

[0060] In step In the present invention, the remote UE 1 sends a direct communication (DC) request message to the relay UE (eg, by broadcasting), and performs authentication and security procedures with the relay UE.

[0061] In steps S503 - S504 , the relay UE forwards the DC request message to the remote UE 2 (eg, by broadcasting), and performs authentication and security procedures with the remote UE 2 .

[0062] In steps S505 to S506 , the relay UE receives a first DC acceptance message from the remote UE 2 , and sends a second DC acceptance message to the remote UE 1 .

[0063] At this point, end-to-end relay transmission with hop-by-hop security is established and available after the remote UE 1 receives the second DC Accept message.

[0064] In steps S507 to S508, remote UE 1 performs authentication and security procedures with remote UE 2, and receives a DC acceptance message from remote UE 2 through end-to-end relay transmission.

[0065] At this point, an end-to-end secure PC5-S connection is established and can be used for subsequent RLC channel and SLRB establishment. Note that the PC5-S connection between remote UE 1 and remote UE 2 passes through the relay UE, but it is assumed that security is end-to-end, so the relay UE cannot read the content of the data packets or signaling messages being exchanged between the two remote UEs.

[0066] Figure 6 It is a message sequence diagram showing the establishment of RLC channel and SLRB in the UE-to-UE relay architecture according to an embodiment of the present application.

[0067] In an embodiment, RLC channel and SLRB establishment occurs as follows Figure 5 After the connection establishment process described in the embodiment is completed, an end-to-end secure PC5-S connection is provided between the remote UE 1 and the remote UE 2.

[0068] In step S601, remote UE 1 sends a first RRCReconfigurationSidelink message to the relay UE, requesting to establish an RLC channel for communication between remote UE 1 and the relay UE. The first RRCReconfigurationSidelink message may include configurations for only certain protocol layers (e.g., only the bottom layer that terminates between remote UE 1 and the relay UE). Figure 1The protocol stack shown in FIG. 1 , which means that the first RRCReconfigurationSidelink message may include configurations of the PHY, MAC, RLC, and adaptation layers. In some embodiments, the first RRCReconfigurationSidelink message may also indicate one or more values ​​of an end-to-end identifier to map to an RLC channel configured by the first RRCReconfigurationSidelink message (e.g., Figure 4 In the scenario of "establishing RLC channel W, which will carry SLRB A"). In other words, the end-to-end identifier value can be assigned by the initiating / sending remote UE. The first RRCReconfigurationSidelink message may also indicate the destination of the SLRB to be established, so that the relay UE can trigger the establishment of the RLC channel with the destination / recipient remote UE. The first RRCReconfigurationSidelink message may also indicate one or more parameters of the SLRB to be established, so that the relay UE can infer the applicable parameters for configuring the RLC channel with the destination / recipient remote UE.

[0069] In step S602, the relay UE responds with a first RRCReconfigurationCompleteSidelink message, indicating that the reconfiguration requested in step S601 has been performed. In some embodiments, the first RRCReconfigurationCompleteSidelink message may indicate one or more values ​​of an end-to-end identifier to be mapped to the RLC channel configured by the first RRCReconfigurationSidelink message. In other words, the end-to-end identifier value may be assigned by the relay UE rather than by the originating / sending remote UE.

[0070] In step S603, the relay UE sends a second RRCReconfigurationSidelink message to the remote UE 2 to establish one or more RLC channels for communication between the relay UE and the remote UE 2. The second RRCReconfigurationSidelink message may include configurations only for certain protocol layers (e.g., layers terminated between the relay and the remote UE 2). In some embodiments, the second RRCReconfigurationSidelink message may also indicate one or more values ​​of an end-to-end identifier to map to the RLC channel configured by the second RRCReconfigurationSidelink message (e.g., "establish RLC channel Y, which will carry SLRB A"). The end-to-end identifier value indicated in the second RRCReconfigurationSidelink message may be the same as or different from the end-to-end identifier value for the same SLRB allocated in steps S601 to S602.

[0071] In step S604, the remote UE 2 sends a second RRCReconfigurationCompleteSidelink message to the relay UE, indicating that the reconfiguration requested in step S603 has been performed. In some embodiments, the second RRCReconfigurationCompleteSidelink message may also indicate one or more values ​​of the end-to-end identifier to be mapped to the RLC channel configured by the second RRCReconfigurationSidelink message. The end-to-end identifier value indicated in the second RRCReconfigurationCompleteSidelink message may be the same as or different from the end-to-end identifier value for the same SLRB allocated in steps S601-S602.

[0072] In step S605, remote UE 1 sends a third RRCReconfigurationSidelink message to remote UE 2 (via the relay UE, using the secure PC5-S connection between remote UE 1 and remote UE 2). The third RRCReconfigurationSidelink message may include configurations only for certain protocol layers (e.g., upper layers terminated between remote UEs). Figure 1In the illustrated protocol stack, this means that the third RRCReconfigurationSidelink message may only include configuration of the PDCP and SDAP layers.The third RRCReconfigurationSidelink message may configure one or more SLRBs between remote UE1 and remote UE2, which may be mapped to the RLC channels configured in steps S601 and S603.

[0073] In step S606, remote UE 2 sends a third RRCReconfigurationCompleteSidelink message to remote UE 1, indicating that the reconfiguration requested in step S605 has been completed.

[0074] It should be noted that in Figure 6 In an embodiment, when the RLC channel is established in steps S601 to S604, the SLRB does not yet exist. That is, steps S601 to S604 include configuring transmission for a non-existent bearer, assuming that the bearer can be established later. Alternatively, steps S605 to S606 may be performed before step S601, i.e., the SLRB is set before the corresponding RLC channel is established. This alternative may result in the existence of the SLRB without underlying support, and actual business traffic cannot be transmitted for the SLRB before steps S601 to S604 are performed and the corresponding RLC channel is established.

[0075] Figure 7 It is a flow chart of a method for relaying UE to support SL communication in a UE-to-UE relay architecture according to an embodiment of the present application.

[0076] In step S701, the relay UE establishes a first RLC channel between the first remote UE and the relay UE, wherein the first RLC channel is associated with a first end-to-end identifier. Figure 6 The first RLC channel is established by the RRC reconfiguration process for SL communication described in steps S601 to S602.

[0077] In step S702, the relay UE establishes a second RLC channel between the second remote UE and the relay UE, wherein the second RLC channel is associated with the first end-to-end identifier or the second end-to-end identifier. Figure 6 The second RLC channel is established by the RRC reconfiguration process for SL communication described in steps S603 to S604.

[0078] In step S703, the relay UE receives an incoming SL transmission from a first remote UE on a first RLC channel, wherein the incoming SL transmission includes a first end-to-end identifier.

[0079] In step S704, the relay UE sends an outgoing SL transmission to a second remote UE on a second RLC channel, wherein the outgoing SL transmission comprises at least a data packet and one of a first end-to-end identifier and a second end-to-end identifier.

[0080] In one embodiment, the outgoing SL transmission may include at least a data packet and a first end-to-end identifier in response to the second RLC channel being associated with the first end-to-end identifier. For example, the first end-to-end identifier may be a path identifier that the relay UE may use to uniquely determine a mapping of an ingress RLC channel and an egress RLC channel for a SLRB between two remote UEs, and the path identifier is common throughout the transmission path.

[0081] In another embodiment, in response to the second RLC channel being associated with the second end-to-end identifier, the outgoing SL transmission may include at least the data packet and the second end-to-end identifier. For example, the first end-to-end identifier may be composed of an identifier of the SLRB carried by the first RLC channel and the second RLC channel (e.g., SLRB identifier) ​​and information of the destination / receiving remote UE (e.g., UE ID or MAC address), and the second end-to-end identifier may be composed of an identifier of the SLRB carried by the first RLC channel and the second RLC channel (e.g., SLRB identifier) ​​and information of the sending / initiating remote UE (e.g., UE ID or MAC address). That is, the first end-to-end identifier and the second end-to-end identifier may be separately assigned for each of the first RLC channel and the second RLC channel, and the relay UE may determine the mapping of the first RLC channel to the second RLC channel for the outgoing SL transmission based on the first end-to-end identifier.

[0082] Figure 8 It is a flow chart of a method for a first remote UE to support SL communication in a UE-to-UE relay architecture according to an embodiment of the present application.

[0083] In an embodiment, the first remote UE may refer to a remote UE that initiates SL communication with another remote UE through a UE-to-UE relay.

[0084] In step S801, a first remote UE establishes an RLC channel between the first remote UE and a relay UE, wherein the first RLC channel is associated with an end-to-end identifier. Figure 6 The RLC channel is established by the RRC reconfiguration process for SL communication described in steps S601 to S602.

[0085] In step S802, after the RLC channel is established, the first remote UE establishes a SLRB between the first remote UE and the second remote UE, wherein the SLRB is associated with an end-to-end identifier. Figure 6 The SLRB is established by the RRC reconfiguration process for SL communication described in steps S605 to S606.

[0086] In step S803, after the SLRB is established, the first remote UE sends a SL transmission for the second remote UE on the RLC channel, wherein the SL transmission includes an end-to-end identifier.

[0087] In one embodiment, the first end-to-end identifier may be a path identifier that the relay UE may use to uniquely determine a mapping of ingress and egress RLC channels for a SLRB between two remote UEs and that is common throughout the transmission path.

[0088] In another embodiment, the end-to-end identifier may be allocated exclusively for the RLC channel, and it may consist of the SLRBID and the information of the destination / receiver remote UE (eg, UE ID or MAC address).

[0089] It should be noted that even though the aforementioned embodiments are directed to a single-hop setting, the method of the present application can also be applied to a multi-hop setting. If there are two or more relay UEs between the sending remote UE and the receiving remote UE, each relay UE needs to know how to map the end-to-end identifier to its own ingress RLC channel and egress RLC channel. This means that when the SLRBs are established, they must be associated with end-to-end identifiers known to the relay UEs. The relay UEs can communicate at the time of establishment to establish a mutually agreed end-to-end identifier. Then, in order to send packets in a multi-hop setting, each relay UE applies the forwarding process as described above.

[0090] Although the present application has been described in an exemplary manner and according to a preferred embodiment, it should be understood that the present application is not limited thereto. Without departing from the scope and spirit of the present application, those skilled in the art may still make various changes and modifications. Therefore, the scope of the present application should be limited and protected by the following claims and their equivalents.

[0091] The use of ordinal terms such as "first", "second", etc. in the claims to refer to claim elements does not itself indicate that one claim element has any priority, precedence or order relative to another claim, or the temporal order of execution of the method of implementation. However, such ordinal terms such as "first", "second", etc. are only used as marks to distinguish one claim element with the same name from another element with the same name (but using ordinal numbers), thereby distinguishing the claim elements.

Claims

1. A side link communication method, performed by a relay user equipment, the method comprising: establishing a first radio link control channel between the first remote user equipment and the relay user equipment, wherein the first radio link control channel is associated with the first end-to-end identifier; establishing a second radio link control channel between a second remote user equipment and the relay user equipment, wherein the second radio link control channel is associated with the first end-to-end identifier or the second end-to-end identifier; receiving an incoming sidelink transmission from the first remote user equipment on the first radio link control channel, wherein the incoming sidelink transmission comprises the first end-to-end identifier, and the first end-to-end identifier comprises a sidelink radio bearer identifier and information of the second remote user equipment; as well as An outgoing sidelink transmission is sent to the second remote user equipment on the second radio link control channel, wherein the outgoing sidelink transmission includes one of the first end-to-end identifier and the second end-to-end identifier.

2. The side link communication method according to claim 1, characterized in that: The outgoing sidelink transmission includes the first end-to-end identifier in response to the second radio link control channel being associated with the first end-to-end identifier.

3. The side link communication method according to claim 2, characterized in that: The method further comprises: A mapping of a first radio link control channel to the second radio link control channel for the outgoing sidelink transmission is determined based on the first end-to-end identifier.

4. The side link communication method according to claim 1, characterized in that: The outgoing sidelink transmission includes the second end-to-end identifier in response to the second radio link control channel being associated with the second end-to-end identifier.

5. The side link communication method according to claim 4, characterized in that: The method further comprises: A mapping of a first radio link control channel to the second radio link control channel for the outgoing sidelink transmission is determined based on the first end-to-end identifier.

6. The side link communication method according to claim 5, characterized in that: The second end-to-end identifier includes the sidelink radio bearer identifier and information of the first remote user equipment.

7. The side link communication method according to claim 6, characterized in that: The information of the first remote user equipment includes a first user equipment identifier of the first remote user equipment, and the information of the second remote user equipment includes a second user equipment identifier of the second remote user equipment.

8. The side link communication method according to claim 1, characterized in that: The first radio link control channel between the first remote user equipment and the relay user equipment is established in the following manner: receiving a first reconfiguration message from the first remote user equipment; and A first reconfiguration completion message is sent to the first remote user equipment.

9. The side link communication method according to claim 8, characterized in that: The first end-to-end identifier is indicated in the first reconfiguration message or in the first reconfiguration complete message.

10. The side link communication method according to claim 1, characterized in that: The second radio link control channel between the second remote user equipment and the relay user equipment is established in the following manner: sending a second reconfiguration message to the second remote user equipment; and A second reconfiguration complete message is received from the second remote user equipment.

11. The side link communication method according to claim 10, characterized in that: The first end-to-end identifier is indicated in the second reconfiguration complete message in response to the second radio link control channel being associated with the first end-to-end identifier, or the second end-to-end identifier is indicated in the second reconfiguration complete message in response to the second radio link control channel being associated with the second end-to-end identifier.

12. The side link communication method according to claim 10, characterized in that: The first end-to-end identifier is indicated in the second reconfiguration message in response to the second radio link control channel being associated with the first end-to-end identifier, or the second end-to-end identifier is indicated in the second reconfiguration message in response to the second radio link control channel being associated with the second end-to-end identifier.

13. A side link communication device, the device being a relay user equipment, the relay user equipment comprising: Memory; Wireless transceiver; as well as A controller coupled to the memory and the wireless transceiver, wherein the controller is configured to: establishing a first radio link control channel between the first remote user equipment and the relay user equipment, wherein the first radio link control channel is associated with the first end-to-end identifier; establishing a second radio link control channel between a second remote user equipment and the relay user equipment, wherein the second radio link control channel is associated with the first end-to-end identifier or the second end-to-end identifier; as well as receiving, via the wireless transceiver, an incoming sidelink transmission from the first remote user equipment on the first radio link control channel, wherein the incoming sidelink transmission includes the first end-to-end identifier, the first end-to-end identifier including a sidelink radio bearer identifier and information of the second remote user equipment; as well as An outgoing sidelink transmission is sent via the wireless transceiver to the second remote user equipment on the second radio link control channel, wherein the outgoing sidelink transmission includes one of the first end-to-end identifier and the second end-to-end identifier.

14. A sidelink communication method, performed by a first remote user device, the method comprising: establishing a radio link control channel between the first remote user equipment and the relay user equipment, wherein the radio link control channel is associated with an end-to-end identifier, the end-to-end identifier comprising a sidelink radio bearer identifier and information of a second remote user equipment; After the radio link control channel is established, establishing a sidelink radio bearer between the first remote user equipment and the second remote user equipment, wherein the sidelink radio bearer is associated with the end-to-end identifier; as well as After the sidelink radio bearer is established, a sidelink transmission for the second remote user equipment is sent on the radio link control channel, wherein the sidelink transmission includes the end-to-end identifier.

15. The side link communication method according to claim 14, characterized in that: The radio link control channel between the first remote user equipment and the relay user equipment is established in the following manner: sending a first reconfiguration message to the relay user equipment; and A first reconfiguration complete message is received from the relay user equipment.

16. The side link communication method according to claim 15, characterized in that: Further including: determining the end-to-end identifier; as well as The end-to-end identifier is indicated in the first reconfiguration message.

17. The side link communication method according to claim 15, characterized in that: The end-to-end identifier is indicated in the first reconfiguration complete message.

18. The side link communication method according to claim 14, characterized in that: The sidelink radio bearer between the first remote user equipment and the second remote user equipment is established by: sending a second reconfiguration message to the second remote user equipment via the relay user equipment; and A second reconfiguration complete message is received from the second remote user equipment via the relay user equipment.

19. The side link communication method according to claim 14, characterized in that: The information of the second remote user equipment includes a user equipment identifier of the second remote user equipment.

20. A sidelink communication device, the device being a remote user equipment, the remote user equipment comprising: Memory; as well as A controller coupled to the memory, wherein the controller is configured to execute the steps of the side link communication method according to any one of claims 14-19.

Images