Differentiation between Traffic in L2 Relay

Abstract

A user equipment (UE) is configured to communicate with another UE via a side link (SL). The UE encodes traffic for transmission to the other UE, where the traffic includes a payload and a media access control (MAC) sub-header, and the MAC sub-header indicates whether the payload corresponds to non-routed traffic between the UE and the other UE or routed traffic between either the UE or the other UE and the base station, and another one of the UE or the other UE acts as a relay for the routed traffic and transmits the traffic.

Description

Technical Field

[0001] The present application generally relates to wireless communication and, more particularly, to the differentiation between traffic in L2 relaying. Background Art

[0002] A user equipment (UE) may be configured with multiple communication links. For example, the UE may receive signals from a cell of a corresponding network via a downlink and may transmit signals to the cell of the corresponding network via an uplink. The UE may also be configured to communicate with another UE via a side link (SL). The term "side link" refers to a communication link that may be used for device-to-device (D2D) communication.

[0003] The SL may be used for relay assistance, which may include forwarding data / signals from the network to a remote UE outside the range of the network and / or with poor network coverage via a relay UE. After successful decoding / encoding and demodulation / modulation of the signal, layer 2 (L2) relaying amplifies the received signal to the destination. In L2 UE-to-NW relaying, two types of traffic may be carried in the SL between the remote UE and the relay UE. The first type of traffic (data / signaling) may be intended to terminate at the relay UE (non-routed traffic between the remote UE and the relay UE), while the second type of traffic may be intended not to terminate at the relay UE (routed traffic between the remote UE and the network). Thus, when handling traffic to / from the remote UE, the relay UE has two roles for delivery (relay and non-relay).

[0004] For L2 relaying, in the uplink (UL), the remote UE currently cannot notify the relay UE of the destination of the traffic it transmits on the UL (the relay UE or the network). In the downlink (DL), if the relay UE combines the two types of traffic (routed traffic and non-routed traffic), the remote UE cannot deliver the different traffic to different RLC / PDCP layers. Summary of the Invention

[0005] Some exemplary embodiments relate to a user equipment (UE) having: a transceiver configured to communicate with at least another UE via a side link (SL); and a processor communicatively coupled to the transceiver and configured to perform operations. The operations include: encoding traffic for transmission to the other UE, where the traffic includes a payload and a media access control (MAC) sub-header, where the MAC sub-header indicates whether the payload corresponds to non-routed traffic between the UE and the other UE or routed traffic between either the UE or the other UE and the base station, where the other of the UE or the other UE serves as a relay for the routed traffic; and transmitting the traffic.

[0006] Other exemplary embodiments relate to a processor of a user equipment (UE) configured to perform operations. The operations include: encoding traffic for transmission from a UE connected via a side link (SL) to another UE, where the traffic includes a payload and a media access control (MAC) sub-header, where the MAC sub-header indicates whether the payload corresponds to non-routed traffic between the UE and the other UE or routed traffic between either the UE or the other UE and a base station, where the other of the UE or the other UE serves as a relay for the routed traffic; and transmitting the traffic.

[0007] Some further exemplary embodiments relate to a user equipment (UE) having: a transceiver configured to communicate via a side link (SL) with at least another UE; and a processor communicatively coupled to the transceiver and configured to perform operations. The operations include: receiving encoded traffic from the other UE, where the encoded traffic includes a payload and a media access control (MAC) sub-header, where the MAC sub-header indicates whether the payload corresponds to non-routed traffic between the UE and the other UE or routed traffic between either the UE or the other UE and a base station, where the other of the UE or the other UE serves as a relay for the routed traffic; and decoding the encoded traffic. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 An exemplary network arrangement is shown in accordance with various exemplary embodiments.

[0009] Figure 2 An exemplary UE is shown in accordance with various exemplary embodiments.

[0010] Figure 3 An arrangement of various protocol functions that can be implemented in a wireless communication device is shown in accordance with various exemplary embodiments.

[0011] Figure 4 An exemplary network diagram including a base station, a relay UE, and a remote UE is shown.

[0012] Figures 5a to 5b A user plane radio protocol stack and a control plane radio protocol stack 550 for L2 evolved UE to network relay are shown.

[0013] Figure 6 An exemplary diagram of two types of data / signaling traffic that can be carried between a relay UE and a remote UE connected via a side link (SL) is shown.

[0014] Figure 7aA side - link (SL) MAC sub - header is shown that has a one - bit type field for indicating UE - UE traffic or UE - NW relay traffic on the SL.

[0015] Figure 7b A signaling diagram for traffic transmitted between a remote UE, a relay UE, and a gNB according to a first exemplary embodiment is shown.

[0016] Figure 8a SL MAC sub - headers according to various exemplary embodiments described herein are shown.

[0017] Figure 8b A signaling diagram for traffic transmitted between a remote UE, a relay UE, and a gNB according to a second exemplary embodiment is shown.

[0018] Figure 8c A signaling diagram for traffic transmitted between a remote UE, a relay UE, and a gNB according to an alternative of the second exemplary embodiment is shown.

[0019] Figures 9a to 9b A discovery procedure using two UE IDs for a relay UE is shown.

[0020] Figures 9c to 9d SL MAC sub - headers for uplink (UL) and downlink (DL) according to a third exemplary embodiment are shown respectively.

[0021] Figure 9e A signaling diagram for traffic transmitted between a remote UE, a relay UE, and a gNB according to a third exemplary embodiment is shown. Detailed Description

[0022] Exemplary embodiments can be further understood with reference to the following description and the related drawings, where like elements have the same reference numerals. The exemplary embodiments relate to operations for differentiating between two types of traffic received at a relay user equipment (UE) in a layer 2 (L2) relay configuration having a base station and a remote UE. The relay UE and the remote UE are configured with side - link (SL) connections, and the relay UE can forward messages from the remote UE to the base station or messages from the base station to the remote UE (routed traffic). However, the remote UE and the relay UE can transmit data / signaling to each other independently of the network (non - routed traffic). The operations described herein relate to a scheme for identifying which traffic is routed and which traffic is not routed.

[0023] Exemplary embodiments are described with respect to a UE. However, the use of the UE is provided merely for illustrative purposes. Exemplary embodiments can be used with any electronic component configured with hardware, software, and / or firmware for exchanging information (e.g., control information) and / or data with a network. Thus, the UE described herein is used to represent any suitable electronic device.

[0024] Exemplary embodiments are also described with reference to a side link (SL). The term "side link" generally refers to a communication link between a UE and another UE. The SL provides direct device-to-device (D2D) communication, where the information and / or data exchanged between a UE and another UE via the side link do not pass through a cell. In some configurations, a single SL provides two-way data communication between a UE and another UE. In other configurations, a single SL provides one-way data communication between a UE and another UE, but signaling can be transmitted in both directions. The term "unicast" refers to one-to-one (i.e., D2D) communication and can generally refer to two-way communication or one-way communication. Various embodiments can be applied to one or both of the communication forms indicated below.

[0025] Both the Long-Term Evolution (LTE) and 5G New Radio (NR) standards support SL communication. In some configurations, the network can provide the UE with information on how to establish, maintain, and / or utilize the SL. Thus, when the information and / or data exchanged via the SL do not pass through a cell, the UE and the network can exchange SL-related information via the network cell. In other configurations, the SL is not controlled by the network. In either configuration, the first UE and the second UE can still perform a synchronization process, a discovery process, and exchange control information corresponding to the SL.

[0026] Figure 1 An exemplary network arrangement 100 according to various exemplary embodiments is shown. The exemplary network arrangement 100 includes UEs 110, 112. Those skilled in the art will understand that the UEs 110, 112 can be any type of electronic component configured to communicate via a network, such as components of a connected vehicle, a mobile phone, a tablet computer, a smart phone, a phablet, an embedded device, a wearable device, an Internet of Things (IoT) device, etc. It should also be understood that an actual network arrangement can include any number of UEs used by any number of users. Thus, the example with two UEs 110, 112 is provided merely for illustrative purposes.

[0027] UEs 110, 112 can communicate directly with one or more networks. In the example of network configuration 100, the networks with which UEs 110, 112 can communicate wirelessly are 5G NR Radio Access Network (5G NR-RAN) 120, LTE Radio Access Network (LTE-RAN) 122, and Wireless Local Area Network (WLAN) 124. These types of networks support sidelink (SL) communication. In the exemplary network arrangement 100, UEs 110 and 112 can be connected via an SL connection. However, UE 110 can also communicate with other types of networks, and UE 110 can also communicate with the network via a wired connection. Thus, UEs 110, 112 can include a 5G NR chipset for communicating with 5G NR-RAN 120, an LTE chipset for communicating with LTE-RAN 122, and an ISM chipset for communicating with WLAN 124.

[0028] 5G NR-RAN 120 and LTE-RAN 122 can be part of cellular networks that can be deployed by cellular providers (e.g., Verizon, AT&T, T-Mobile, etc.). These networks 120, 122 can include, for example, cells or base stations (NodeB, eNodeB, HeNB, eNBS, gNB, gNodeB, macro cell base stations, micro cell base stations, small cell base stations, femto cell base stations, etc.) configured to send and receive traffic from UEs equipped with appropriate cellular chipsets. WLAN 124 can include any type of wireless local area network (WiFi, hotspots, IEEE 802.11x networks, etc.).

[0029] UEs 110, 112 can be connected to 5G NR-RAN via gNB 120A. The reference to a single gNB 120A is for illustrative purposes only. Exemplary embodiments can be applied to any appropriate number of gNBs. UEs 110, 112 can also be connected to LTE-RAN 122 via eNB 122A.

[0030] Those skilled in the art will understand that any associated processes can be performed for UEs 110, 112 to connect to 5G NR-RAN 120 and LTE-RAN 122. For example, as discussed above, 5G NR-RAN 120 and LTE-RAN 122 can be associated with a particular cellular provider where the UEs 110, 112 and / or their users have contract and credential information (e.g., stored on a SIM card). When the presence of 5G NR-RAN 120 is detected, UEs 110, 112 can transmit the corresponding credential information to associate with 5G NR-RAN 120. More specifically, UEs 110, 112 can associate with a particular base station (e.g., gNB 120A of 5G NR-RAN 120, eNB 122A of LTE-RAN 122).

[0031] UEs 110, 112 can also communicate directly with each other using SL. SL is a direct device-to-device (D2D) communication link. Thus, information and / or data transmitted directly to another endpoint (e.g., UE 110 or UE 112) do not pass through a cell (e.g., gNB 120A, eNB 122A). In some embodiments, UEs 110, 112 can receive information from the cell on how to establish, maintain, and / or utilize SL. Thus, the network (e.g., 5G NR-RAN 120, LTE-RAN 122) can control SL. In other embodiments, UEs 110, 112 can control SL. Regardless of how SL is controlled, UEs 110, 112 can simultaneously maintain a downlink / uplink to the currently camped cell (e.g., gNB 120A, eNB 122A) and an SL to another UE.

[0032] In addition to networks 120, 122, and 124, network arrangement 100 also includes a cellular core network 130, the Internet 140, an IP multimedia subsystem (IMS) 150, and a network service backbone 160. Cellular core network 130 can be regarded as an interconnected collection of components that manage the operations and traffic of a cellular network (e.g., 5GC in NR). Cellular core network 130 also manages the traffic flowing between the cellular network and the Internet 140.

[0033] The IMS 150 can generally be described as an architecture for delivering multimedia services to the UE 110 using IP protocols. The IMS 150 can communicate with the cellular core network 130 and the Internet 140 to provide multimedia services to the UE 110. The network service backbone 160 communicates directly or indirectly with the Internet 140 and the cellular core network 130. The network service backbone 160 can generally be described as a set of components (e.g., servers, network storage arrangements, etc.) that implement a set of services that can be used to extend the functionality of the UE 110 to communicate with various networks.

[0034] Figure 2 An exemplary UE 110 is shown in accordance with various exemplary embodiments. The UE 110 will be described with reference to Figure 1 the network arrangement 100. The UE 110 can include a processor 205, a memory arrangement 210, a display device 215, an input / output (I / O) device 220, a transceiver 225, and other components 230. The other components 230 can include, for example, a SIM card, an embedded SIM (eSIM), an audio input device, an audio output device, a power source, a data acquisition device, a port for electrically connecting the UE 110 to other electronic devices, etc. Figure 2 The UE 110 shown in

[0035] The processor 205 can be configured to execute multiple engines of the UE 110. For example, the engines can include a layer 2 (L2) relay engine 235. The L2 relay engine 235 can perform L2 relay operations, including forwarding traffic between a remote UE and a base station (when the UE 110 is a relay UE in the L2 relay operation) and transmitting / receiving traffic to / from the relay UE (when the UE 110 is a remote UE in the L2 relay operation). The L2 relay engine can perform additional operations, including differentiating between two types of traffic (routed traffic or non-routed traffic) in the L2 relay operation, which will be described in further detail below. Those skilled in the art will understand that the remote UE in the L2 relay operation may or may not include the relay capability of the relay UE, and the relay UE in the L2 relay operation may or may not include the relay capability of the remote UE. However, the UE 110 as described herein can be capable of operating as either a relay UE or a remote UE.

[0036] The above engines, each as an application (e.g., program) executed by the processor 205, are merely exemplary. The functions associated with the engines can also be represented as separate integrated components of the UE 110, or can be modular components coupled to the UE 110, e.g., integrated circuits with or without firmware. For example, an integrated circuit can include input circuitry for receiving signals and processing circuitry for processing signals and other information. The engines can also be embodied as one application or separate multiple applications. Additionally, in some UEs, the functionality described for the processor 205 is shared between two or more processors such as a baseband processor and an application processor. The exemplary embodiments can be implemented in any of these or other configurations of the UE.

[0037] The memory arrangement 210 can be a hardware component configured to store data related to operations performed by the UE 110. The display device 215 can be a hardware component configured to display data to the user, while the I / O device 220 can be a hardware component that enables the user to make inputs. The display device 215 and the I / O device 220 can be separate components or can be integrated together (such as a touchscreen). The transceiver 225 can be a hardware component configured to establish connections with the 5G NR-RAN 120, WLAN 122, etc. Thus, the transceiver 225 can operate on multiple different frequencies or channels (e.g., a continuous frequency band).

[0038] As described above, device-to-device (D2D) communication can be direct communication between two devices or relay-assisted communication. Relay assistance can include fixed low-power relays for forwarding signals from the network to devices outside the network range and / or with poor network coverage. Layer 1 relay includes a repeater station that amplifies the received signal and forwards the amplified signal to the destination, e.g., to a sidelink (SL) UE (amplifying network signals on the downlink) or to a network component (amplifying SL UE signals on the uplink). After successful decoding / encoding and demodulation / modulation of the signal, layer 2 relay amplifies the received signal to the destination. Layer 3 relay has a similar function to layer 2 relay but includes additional radio protocols. Layer 1 (L1) generally refers to the physical (PHY) layer of the UE / RAN node. Layer 2 (L2) generally refers to the medium access (MAC) layer, radio link control (RLC) layer, and packet data convergence protocol (PDCP) layer, and is considered a higher layer than L1. Layer 3 (L3) generally refers to the radio resource control (RRC) layer, and is considered a higher layer than L2.

[0039] Figure 3 An arrangement 300 of various protocol functions that can be implemented in a wireless communication device according to various exemplary embodiments is shown. Specifically, Figure 3An example of the MAC layer 305, RLC layer 310, and PDCP layer 315 is shown.

[0040] An example of MAC 305 can process requests from an example of RLC 310 via one or more MAC service access points (SAs) and provide indications thereto. These requests and indications transmitted via the MAC-SAP can include one or more logical channels. MAC 305 can perform mapping between logical channels and transport channels, multiplex MAC service data units (SDUs) from one or more logical channels onto transport blocks (TBs) delivered to the PHY via the transport channels, demultiplex MAC SDUs from the TBs delivered from the PHY via the transport channels onto one or more logical channels, multiplex MAC SDUs onto TBs, schedule information reporting, error correction via HARQ, and logical channel prioritization.

[0041] An example of RLC 310 can process requests from an example of PDCP 315 via one or more radio link control service access points (RLC-SAPs) and provide indications thereto. These requests and indications transmitted via the RLC-SAP can include one or more RLC channels. RLC 630 can operate in multiple operation modes, including: transparent mode (TM), unacknowledged mode (UM), and acknowledged mode (AM). RLC 310 can perform transfer of upper layer protocol data units (PDUs), error correction via automatic repeat request (ARQ) for AM data transfer, and concatenation, segmentation, and reassembly of RLC SDUs for UM and AM data transfer. RLC 310 can also perform resegmentation of RLC data PDUs for AM data transfer, reordering of RLC data PDUs for UM and AM data transfer, detection of duplicate data for UM and AM data transfer, discarding of RLC SDUs for UM and AM data transfer, detection of protocol errors for AM data transfer, and perform RLC re-establishment.

[0042] An instance of PDCP 315 can process requests from an instance of RRC and / or an instance of SDAP via one or more Packet Data Convergence Protocol Service Access Points (PDCP-SAPs) and provide indications thereto. These requests and indications transmitted via the PDCP-SAPs can include one or more radio bearers. PDCP 315 can perform header compression and decompression of IP data, maintain a PDCP Sequence Number (SN), perform in-sequence delivery of upper layer PDUs upon re-establishment of the lower layer, eliminate duplicates of lower layer SDUs when re-establishing the lower layer for radio bearers mapped to RLC AM, encrypt and decrypt control plane data, perform integrity protection and integrity verification on control plane data, control timer-based data discard, and perform security operations (e.g., encryption, decryption, integrity protection, integrity verification, etc.).

[0043] Layer 2 (L2) User Equipment (UE) to Network (NW) relay enables a remote device (e.g., a wearable device such as a watch) to access a cellular network via a relay device (e.g., a phone). Figure 4 An exemplary network diagram 400 including a base station 405, a relay UE 410, and a remote UE 415 is shown. The relay UE 410 is shown to be within the coverage area of the base station 405 and capable of exchanging signaling / data with the base station 405, while the remote UE 415 is shown to be out of service of the base station 405. However, in some exemplary embodiments described herein, the remote UE 415 can be within the coverage area of the base station 405 and exchange signaling / data therewith. The relay UE 410 and the remote UE 415 can be connected via an SL configured by the network as an L2 relay.

[0044] Figures 5a to 5b A user plane radio protocol stack 500 and a control plane radio protocol stack 550 for L2 evolved UE to network relay are shown. For both protocol architectures (user plane and control plane), relay is performed at the RLC sublayer. The Uu interface for PDCP and RRC terminates between the remote UE and the eNB, while RLC, MAC, and PHY, and the non-3GPP transport layer terminate in each link (remote UE to relay UE, and relay UE to network).

[0045] In a network arrangement including L2 UE to NW relay, two types of traffic (data / signaling) can be carried in the SL between the remote UE and the relay UE, i.e., traffic that ends at the relay UE (non-routed traffic between the remote UE and the relay UE) and traffic that does not end at the relay UE (routed traffic between the UE and the network). When processing SL traffic from the remote UE, the relay UE has two roles for traffic delivery (relay and non-relay).

[0046] Figure 6Exemplary FIG. 600 shows two types of data / signaling traffic that can be carried between a relay UE 610 and a remote UE 615 connected via a side link (SL). The remote UE 615 can transfer, on the uplink (UL), first data / signaling 620 destined for the relay UE 610 or second data / signaling 625 destined for the network 605 (via the relay UE 610). Regarding the downlink (DL), the relay UE 610 can transfer first data / signaling 620 originating at the relay UE 610 or second data / signaling 625 originating at the network 605 (and forwarded by the relay UE 610) to the remote UE 615.

[0047] On the UL, there is no current function to notify the relay UE about the destination of traffic received from the remote UE on the SL. On the DL, if the relay UE combines traffic originating at the relay UE and traffic originating at the network, there is no current function for the remote UE to distinguish between these two types of traffic. The remote UE cannot deliver different types of traffic (combined in a PDU) to different RLC / PDCP instances.

[0048] According to various exemplary embodiments described herein, operations are defined such that traffic of a UE can be distinguished in a layer 2 (L2) relay operation.

[0049] In some exemplary embodiments, a type field is added to the SL MAC sub-header to indicate one of two different types of traffic. Figure 7a FIG. shows a side link (SL) MAC sub-header 700 with a one-bit type field 705 that is used to indicate non-routed traffic (e.g., UE-UE traffic) or routed traffic (e.g., UE-NW relay traffic) on the SL. The type field 705 can be a repurposed reserved (R) bit from an existing MAC sub-header.

[0050] Figure 7b Signaling diagram 750 shows traffic transmitted between a remote UE 765, a relay UE 760, and a gNB 755 according to a first exemplary embodiment. Signaling diagram 750 relates to traffic originating at the remote UE 765 and destined for the relay UE 760 (non-routed SL traffic) or destined for the gNB 755 (routed uplink (UL) traffic), but this exemplary embodiment can be modified for downlink (DL) traffic, which will be further described below.

[0051] Non-routed traffic (not originating or terminating at gNB 755) between the remote UE 765 and the relay UE 760 can be indicated in the MAC sub-header 700 with the type field 705 set to "0", while routed traffic between the remote UE 765 and the gNB 755 (using the relay UE 760 as a relay node) can be indicated in the MAC sub-header 700 with the type field 705 set to "1". As Figure 7b shown, the payload 770 transmitted from the remote UE 765 and indicated as going to the relay UE 760 will terminate at the relay UE 760. The payload 775 transmitted from the remote UE 765 and indicated as going to the gNB 755 will be forwarded from the relay UE 760 to the gNB 755.

[0052] The relay UE 760 and the remote UE 765 can identify each other using the same UE ID in the source ID and destination ID fields of the SL MAC sub-header 700, e.g., because the type field will identify the specific UE (remote or relay) to which the data is addressed. In some exemplary embodiments, there may be only one SL MAC sub-header. In this scenario, the two types of traffic cannot be multiplexed into the same MAC PDU, as Figure 7b shown in the exemplary signaling diagram 750 of. For example, non-routed traffic is transmitted via a first PDU session, and routed UE-to-NW traffic is transmitted via a second PDU session. In other exemplary embodiments, more than one SL MAC sub-header may be used, and then the two types of traffic can be multiplexed into the same MAC PDU.

[0053] Regarding the DL, the MAC sub-header 700 can be used in a manner substantially similar to that on the UL to distinguish non-routed traffic from the relay UE 760 to the remote UE 765 (originating at the relay UE 760 and not involving the network) or routed traffic from the gNB 755 (and using the relay UE 760 to forward the traffic to the remote UE 765). For example, the relay UE 760 can receive routed traffic from the gNB 755 for routing to the remote UE 765 and can also process traffic originating at the relay UE 760 for direct transmission to the remote UE 765. The relay UE 760 can use the MAC sub-header 700 and the type field as described above to indicate the source of the traffic to distinguish the traffic types.

[0054] In some exemplary embodiments, different logical channels may be configured by the gNB for different types of traffic. A first logical channel ID (LCID) may be used to indicate non-routed traffic (e.g., UE-UE traffic), and a second LCID may be used to indicate routed traffic (e.g., UE-NW traffic). The exemplary embodiments described below have the benefit that two types of traffic can be multiplexed into one MAC PDU. In addition, the relay UE only needs one UE ID.

[0055] For traffic from a remote UE to the network, the SL signaling radio bearer (SLRB) may be configured by the relay UE. According to the procedures found in <RemoteUE RRC Connection Procedure>, the SRB for these transmissions may come from the gNB.

[0056] For traffic from a remote UE to the relay UE, the sidelink radio bearer (SLRB) may be configured in different ways according to the following scenarios. In the first scenario, the remote UE may be within the network coverage of the gNB. In this scenario, the remote UE requests UE-specific SLRB configuration from the gNB. The remote UE sends an SLRB request message to the gNB, and the gNB configures an SL logical channel dedicated to non-routed traffic. For example, the gNB may send a unicast message to configure the SL logical channel. In the second scenario, when the remote UE is within the network coverage of the gNB, the gNB may perform cell-specific SLRB configuration, where the gNB configures the SLRB with a logical channel dedicated to non-routed traffic. For example, the gNB may send a broadcast message to configure the SL logical channel. In the third scenario, the remote UE may be outside the coverage of the gNB. In this scenario, a pre-configured SLRB logical channel is dedicated to non-routed traffic. For example, it is defined by a standard and previously stored on the remote UE, from a previous configuration connected to the gNB or the network, etc.

[0057] Figure 8a An SL MAC sub-header 800 according to various exemplary embodiments described herein is shown. The MAC sub-header 800 may be an existing MAC sub-header and includes a source LCID and a destination LCID (and does not include a type field, as described above for the MAC sub-header 700).

[0058] Figure 8bSignaling diagram 850 shows traffic transmitted between remote UE 865, relay UE 860, and gNB 855 according to various exemplary embodiments. Signaling diagram 850 pertains to traffic originating at remote UE 865 and destined for relay UE 860 (non-routed traffic) or destined for gNB 855 (routed uplink (UL) traffic), but this exemplary embodiment can be modified for downlink (DL) traffic, which will be further described below.

[0059] Non-routed traffic between remote UE 865 and relay UE 860 (not terminating at gNB 855) can be indicated in the MAC sub-header 800 with a destination ID corresponding to the LCID of the channel between remote UE 865 and relay UE 860. Routed traffic between remote UE 865 and gNB 855 (using relay UE 860 as a relay node) can be indicated in the MAC sub-header 800 with a destination ID corresponding to the LCIS of the channel between remote UE 865 and gNB 855. As Figure 8b shown, payload 870 transmitted from remote UE 865 and indicated as destined for relay UE 860 will terminate at relay UE 860. Payload 875 transmitted from remote UE 865 and indicated as destined for gNB 855 will be forwarded from relay UE 860 to gNB 855.

[0060] Regarding the DL, the MAC sub-header 800 can be used in a manner substantially similar to that on the UL to distinguish traffic from relay UE 860 to remote UE 865 originating at relay UE 860 (and not involving the network) or originating at gNB 855 (and using relay UE 860 to forward the traffic to remote UE 865). For example, relay UE 860 can receive traffic from gNB 855 for routing to remote UE 865 and can also process traffic originating at relay UE 860 for direct transmission to remote UE 865. Relay UE 860 can use the MAC sub-header 800 and indicate the source of the traffic with the LCID of the source to distinguish the traffic types.

[0061] According to other exemplary embodiments, a set of LCID ranges can be reserved to distinguish traffic termination at the relay UE or gNB. These exemplary embodiments operate based on the LCID division between the two traffic terminations. These exemplary embodiments can be applied even when different traffic is multiplexed in the same MAC PDU.

[0062] A standardized LCID threshold (LCIDthresh) value can be defined such that the segmentation process is implicit. For example, all traffic destined for termination at the relay UE can use LCIDs less than LCIDthresh, and all traffic destined for the gNB can use LCIDs greater than LCIDthresh.

[0063] Figure 8c A signaling diagram 880 of traffic transmitted between a remote UE 865, a relay UE 860, and a gNB 855 is shown according to various exemplary embodiments. The signaling diagram 880 is substantially similar to the signaling diagram 850 discussed above with respect to Figure 8b However, the source ID field / destination ID field of the MAC sub-header 800 can include any ID within the ID range, as discussed above. When the LCID is greater than or less than LCIDthresh, the traffic corresponding to the MAC sub-header 800 is routed to the corresponding destination.

[0064] In a further exemplary embodiment, two IDs can be defined for the two roles of the relay UE. Currently, the application server (AS) layer UE ID is derived from the upper layer UE ID. According to a further exemplary embodiment, the upper layer can assign two UE IDs to the relay UE (a normal UE ID for UE-to-UE SL communication (non-routed traffic) and a relay UE ID for UE-to-NW relay communication (routed traffic)). The two UE IDs for the relay UE are independent, and the two types of traffic may not be multiplexed into one MAC PDU.

[0065] Figures 9a to 9b A discovery procedure for using two UE IDs for the relay UE is shown according to various exemplary embodiments. In Figure 9a , the relay UE uses the "normal" UE ID in the discovery advertisement to establish a one-to-one communication with the remote UE for non-routed services. In Figure 9b , the relay UE uses the "relay" UE ID in the discovery advertisement to establish a one-to-one communication with the remote UE for routed services.

[0066] Figures 9c to 9d SL MAC sub-headers 900, 905 for the uplink (UL) and downlink (DL) respectively are shown according to a third exemplary embodiment. In Figure 9c , the destination ID field of the SL MAC sub-header 900 (UL) can include either of the two UE IDs discussed above. In Figure 9d , the source ID field of the SL MAC sub-header 905 (DL) can include either of the two UE IDs discussed above, which will be further described below.

[0067] Figure 9e Signaling diagram 950 showing traffic transmitted between remote UE 965, relay UE 960, and gNB 955 according to a third exemplary embodiment. Signaling diagram 950 relates to traffic originating at remote UE 965 and destined for relay UE 960 (SL traffic) or destined for gNB 955 (uplink (UL) traffic), but this exemplary embodiment can be modified for downlink (DL) traffic, which will be described further below. When the remote UE 965 uses the normal UE ID in the MAC sub-header 900, the payload 970 corresponding to the MAC sub-header 900 will terminate at the relay UE 965. When the remote UE 965 uses the relay UE ID in the MAC sub-header 900, the payload 975 corresponding to the MAC sub-header 900 will be routed by the relay UE 965 to the gNB 955.

[0068] Regarding the DL, the MAC sub-header 905 can be used in a similar manner as on the UL to distinguish traffic originating at the relay UE 960 (and not involving the network) or originating at the gNB 955 (and using the relay UE 960 to forward the traffic to the remote UE 965) from the relay UE 960 to the remote UE 965. For example, the relay UE 960 can receive traffic from the gNB 955 for routing to the remote UE 965, and can also process traffic originating at the relay UE 960 for direct transmission to the remote UE 965. The relay UE 960 can use the MAC sub-header 905 to distinguish the traffic type, and use the normal UE ID or the relay UE ID to indicate the source of the traffic.

[0069] Those skilled in the art will understand that the above-described exemplary embodiments can be implemented in any suitable software configuration or hardware configuration or a combination thereof. Exemplary hardware platforms for implementing the exemplary embodiments can include, for example, an Intel x86-based platform with a compatible operating system, Windows OS, Mac platform, and MAC OS, mobile devices with operating systems such as iOS, Android, etc. In other examples, the exemplary embodiments of the above methods can be embodied as a program including lines of code stored on a non-transitory computer-readable storage medium, which, when compiled, can be executed on a processor or a microprocessor.

[0070] Although this patent application describes various combinations of various embodiments each having different features, those skilled in the art will understand that any feature of one embodiment can be combined with the features of other embodiments in any way not negated by the disclosure, or with features that are not functionally or logically inconsistent with the operation of the devices of the embodiments disclosed in the present invention or the said functions.

[0071] As is well known, the use of personally identifiable information should comply with privacy policies and practices that are recognized as meeting or exceeding industry or government requirements for maintaining user privacy. Specifically, personally identifiable information data should be managed and processed to minimize the risk of inadvertent or unauthorized access or use, and the nature of the authorized use should be clearly explained to users.

[0072] It will be apparent to those skilled in the art that various modifications can be made to the present disclosure without departing from the essence or scope of the present disclosure. Accordingly, the present disclosure is intended to cover modifications and variations of the present disclosure, provided that these modifications and variations are within the scope of the appended claims and their equivalents.

Claims

1. A user equipment (UE) comprising: a transceiver configured to communicate with at least one other UE via a side link (SL); and a processor communicatively coupled to the transceiver and configured to perform operations including: establishing a first unicast link with the other UE for non-routed traffic between the UE and the other UE; establishing a second unicast link with the other UE for routed traffic to a base station of a network; encoding traffic for transmission to the other UE, wherein the traffic is one of non-routed traffic and routed traffic, and wherein the traffic includes a payload and a medium access control (MAC) sub-header; and transmitting the traffic to the other UE.

2. The UE according to claim 1, wherein the UE is a remote UE and the other UE is a relay UE, wherein the MAC sub-header indicates whether the payload corresponds to the non-routed traffic between the UE and the other UE or the routed traffic between the UE and the base station, and the MAC sub-header indicates the non-routed traffic as SL traffic to be terminated at the relay UE or the routed traffic as uplink (UL) traffic to be relayed by the relay UE to the base station.

3. The UE according to claim 2, wherein the indication in the MAC sub-header includes a one-bit type field.

4. The UE according to claim 2, wherein when the payload is SL traffic, the operations further include: multiplexing the payload and another payload including UL traffic into the same MAC protocol data unit (PDU).

5. The UE according to claim 2, wherein the indication in the MAC sub-header includes a first logical channel ID (LCID) indicating the SL traffic or a second LCID indicating the UL traffic.

6. The UE according to claim 5, wherein the operations further include: receiving an SL signaling radio bearer (SLRB) configuration from one of the relay UE or the base station for transmitting additional SL traffic.

7. The UE according to claim 5, wherein the operations further include: when the remote UE is within the coverage area of the base station, transmitting an SL signaling radio bearer (SLRB) request message for a UE-specific SLRB configuration to the base station; and receiving an SL logical channel configuration dedicated to the SL traffic.

8. The UE according to claim 5, wherein the operations further include: when the remote UE is within the coverage area of the base station, receiving a cell-specific SL logical channel configuration dedicated to the SL traffic from the base station.

9. The UE according to claim 5, wherein when the value of the first LCID is less than a threshold, the first LCID indicates the SL traffic, and when the value of the second LCID is greater than the threshold, the second LCID indicates the UL traffic.

10. The UE according to claim 2, wherein the indication in the MAC sub-header comprises a first UE ID corresponding to the SL traffic of the relay UE or a second UE ID corresponding to the UL traffic of the relay UE.

11. The UE according to claim 1, wherein the UE is a relay UE and the other UE is a remote UE, and the MAC sub-header indicates the non-routed traffic as SL traffic originating at the relay UE or indicates the routed traffic as downlink DL traffic originating at the base station and relayed by the relay UE.

12. The UE according to claim 11, wherein the indication in the MAC sub-header comprises a one-bit type field.

13. The UE according to claim 11, wherein when the payload is SL traffic, the operation further comprises: Multiplexing the payload and another payload including DL traffic into the same MAC protocol data unit PDU.

14. The UE according to claim 11, wherein the indication in the MAC sub-header comprises a first logical channel ID LCID indicating the SL traffic or a second LCID indicating the DL traffic.

15. The UE according to claim 14, wherein the operation further comprises: Configuring an SL signaling radio bearer SLRB configuration for the remote UE to transmit additional SL traffic.

16. The UE according to claim 14, wherein the remote UE either i) when the remote UE is in the coverage area of the base station, transmits an SL signaling radio bearer SLRB request message for a UE-specific SLRB configuration to the base station and receives an SL logical channel configuration dedicated to the SL traffic, or ii) when the remote UE is in the coverage area of the base station, receives a cell-specific SL logical channel configuration dedicated to the SL traffic from the base station.

17. The UE according to claim 14, wherein when the value of the first LCID is less than a threshold, the first LCID indicates the SL traffic, and when the value of the second LCID is greater than the threshold, the second LCID indicates the DL traffic.

18. The UE according to claim 11, wherein the operation further comprises: Receiving a configuration of a first UE ID corresponding to the SL traffic or a second UE ID corresponding to the DL traffic, wherein the indication in the MAC sub-header comprises the first UE ID or the second UE ID.

19. The UE according to claim 1, wherein the UE and the other UE are configured by the base station for layer 2 L2 relay operation.

20. A non-transitory computer-readable storage medium storing a program, which when executed by a processor of a user equipment UE causes operations to be performed, the operations including: Establishing a first unicast link with another UE for non-routed traffic between the UE and the other UE; Establishing a second unicast link with the other UE for routed traffic to a base station of the network; Encode traffic for transmission from the UE to the other UE, where the traffic is one of non-routed traffic and routed traffic, and where the traffic includes a payload and a Medium Access Control (MAC) sub-header; and Transmit the traffic to the other UE.

21. The non-transitory computer-readable storage medium according to claim 20, wherein the UE is a remote UE and the other UE is a relay UE, and wherein the MAC sub-header indicates whether the payload corresponds to the non-routed traffic between the UE and the other UE or the routed traffic between the UE and the base station, and the MAC sub-header indicates the non-routed traffic as SL traffic to terminate at the relay UE or indicates the routed traffic as uplink (UL) traffic to be relayed by the relay UE to the base station.

22. The non-transitory computer-readable storage medium according to claim 21, wherein the indication in the MAC sub-header includes a one-bit type field.

23. The non-transitory computer-readable storage medium according to claim 21, wherein when the payload is SL traffic, the operations further include: Multiplex the payload and another payload including UL traffic into the same MAC protocol data unit (PDU).

24. The non-transitory computer-readable storage medium according to claim 21, wherein the indication in the MAC sub-header includes a first logical channel ID (LCID) indicating the SL traffic or a second LCID indicating the UL traffic.

25. The non-transitory computer-readable storage medium according to claim 24, wherein the operations further include: Receive an SL signaling radio bearer (SLRB) configuration from the relay UE or the base station for transmitting additional SL traffic.

26. The non-transitory computer-readable storage medium according to claim 24, wherein the operations further include: When the remote UE is in the coverage area of the base station, transmit an SL signaling radio bearer (SLRB) request message for a UE-specific SLRB configuration to the base station; And Receive an SL logical channel configuration dedicated to the SL traffic.

27. The non-transitory computer-readable storage medium according to claim 24, wherein the operations further include: When the remote UE is in the coverage area of the base station, receive a cell-specific SL logical channel configuration dedicated to the SL traffic from the base station.

28. The non-transitory computer-readable storage medium according to claim 24, wherein when the value of the first LCID is less than a threshold, the first LCID indicates the SL traffic, and when the value of the second LCID is greater than the threshold, the second LCID indicates the UL traffic.

29. The non-transitory computer-readable storage medium according to claim 21, wherein the indication in the MAC sub-header includes a first UE ID of the relay UE corresponding to the SL traffic or a second UE ID of the relay UE corresponding to the UL traffic.

30. The non-transitory computer-readable storage medium according to claim 20, wherein the UE is a relay UE and the additional UE is a remote UE, and the MAC sub-header indicates the non-routed traffic as SL traffic originating at the relay UE or indicates the routed traffic as downlink DL traffic originating at the base station and relayed by the relay UE.

31. The non-transitory computer-readable storage medium according to claim 30, wherein the indication in the MAC sub-header includes a one-bit type field.

32. The non-transitory computer-readable storage medium according to claim 30, wherein when the payload is SL traffic, the operation further includes: multiplexing the payload and an additional payload including DL traffic into the same MAC protocol data unit PDU.

33. The non-transitory computer-readable storage medium according to claim 30, wherein the indication in the MAC sub-header includes a first logical channel ID LCID indicating the SL traffic or a second LCID indicating the DL traffic.

34. The non-transitory computer-readable storage medium according to claim 33, wherein the operation further includes: configuring an SL signaling radio bearer SLRB configuration for the remote UE to transmit additional SL traffic.

35. The non-transitory computer-readable storage medium according to claim 33, wherein the remote UE either i) when the remote UE is in the coverage area of the base station, transmits an SL signaling radio bearer SLRB request message for UE-specific SLRB configuration to the base station and receives an SL logical channel configuration dedicated to the SL traffic, or ii) when the remote UE is in the coverage area of the base station, receives a cell-specific SL logical channel configuration dedicated to the SL traffic from the base station.

36. The non-transitory computer-readable storage medium according to claim 33, wherein when the value of the first LCID is less than a threshold, the first LCID indicates the SL traffic, and when the value of the second LCID is greater than the threshold, the second LCID indicates the DL traffic.

37. The non-transitory computer-readable storage medium according to claim 30, wherein the operation further includes: receiving a configuration of a first UE ID corresponding to the SL traffic or a second UE ID corresponding to the DL traffic, wherein the indication in the MAC sub-header includes the first UE ID or the second UE ID.

38. The non-transitory computer-readable storage medium according to claim 20, wherein the UE and the additional UE are configured by the base station in layer 2 L2 relay.

39. A user equipment UE, comprising: a transceiver configured to communicate via a side link SL with at least one additional UE; and a processor communicatively coupled to the transceiver and configured to perform operations including the following: Establish a first unicast link with the other UE for non-routed traffic between the UE and the other UE; Establish a second unicast link with the other UE for routed traffic to a base station of the network; Receive encoded traffic from the other UE, where the encoded traffic is one of non-routed traffic and routed traffic, and where the traffic includes a payload and a Media Access Control (MAC) sub-header; And Decode the encoded traffic.

40. The UE according to claim 39, wherein the UE is a relay UE and the other UE is a remote UE, and wherein the MAC sub-header indicates whether the payload corresponds to the non-routed traffic between the UE and the other UE or the routed traffic between the UE and the base station, and the MAC sub-header indicates the non-routed traffic as SL traffic to be terminated at the relay UE, or indicates the routed traffic as uplink (UL) traffic to be relayed by the relay UE to the base station.

41. The UE according to claim 40, wherein the operations further include: When the MAC sub-header indicates UL traffic, relay the UL traffic to the base station; And When the MAC sub-header indicates SL traffic, do not relay the SL traffic to the base station.

42. The UE according to claim 39, wherein the UE is a remote UE and the other UE is a relay UE, and the MAC sub-header indicates the non-routed traffic as SL traffic originating from the relay UE, or indicates the routed traffic as downlink (DL) traffic originating from the base station and relayed by the relay UE.

43. The UE according to claim 42, wherein the payload is SL traffic and is multiplexed in the same protocol data unit (PDU) with another payload including DL traffic, and wherein the operations further include: Demultiplex the payload and determine the payload as SL traffic; And demultiplex the other payload and determine the other payload as DL traffic.

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