WO2021136379A1

WO2021136379A1 - Early packet filtering for sidelink ue discovery

Info

Publication number: WO2021136379A1
Application number: PCT/CN2020/141419
Authority: WO
Inventors: Xuelong Wang; Tao Chen; Nathan Edward Tenny
Original assignee: Mediatek Singapore Pte. Ltd.
Priority date: 2019-12-30
Filing date: 2020-12-30
Publication date: 2021-07-08
Also published as: WO2021134163A1

Abstract

Apparatus and methods are provided for early packet filtering for sidelink UE discovery. In one novel aspect, the UE detects sidelink UE discovery message information in MAC header of MAC PDU carrying PC5-S discovery message. The MAC PDU carrying the Discovery Announcement has the whole or part of the 24-bit SRC and DST fields set to the be relay UE ID and the relay service code, respectively. The MAC PDU carrying the Discovery Solicitation has the whole or part of the 24-bit SRC and DST fields set to be one of the remote UE ID, relay service code or query code and relay UE ID, respectively. The MAC PDU carrying the Discovery Response has the whole or part of the 24-bit SRC and DST fields set to be one of the relay UE ID and one ofremote UE ID, relay service code or response code, respectively.

Description

EARLY PACKET FILTERING FOR SIDELINK UE DISCOVERY

CROSS REFERENCE TO RELATED APPLICATIONS

This application is filed under 35 U.S.C. §111 (a) and is based on and hereby claims priority under 35 U.S.C. §120 and §365 (c) from International Application No. PCT/CN2019/129793, titled “Methods and Apparatus of Early Packet Filtering for Sidelink UE Discovery, ” with an international filing date of December 30, 2019. The disclosure of each of the foregoing documents is incorporated herein by reference.

TECHNICAL FIELD

The disclosed embodiments relate generally to wireless communication, and, more particularly, to early packet filtering for sidelink UE discovery.

BACKGROUND

5G radio access technology will be a key component of the modern access network. It will address high traffic growth and increasing demand for high-bandwidth connectivity. Wireless relay in cellular networks provides extended coverage and improved transmission reliability. Long term evolution (LTE) network introduced 3GPP sidelink, the direct communication between two user equipment (UEs) without signal relay through a base station. In 3GPP New Radio (NR) , sidelink continues evolving. With new functionalities supported, the sidelink offers low latency, high reliability and high throughout for device to device communications. In the current 3GPP network, the operation for sidelink discovery is based on a specific physical channel, such as the physical sidelink discovery channel (PSDCH) . The intention of sidelink discovery is to discover a user equipment (UE) before establishing a communication link with it. The UE-to-Network relay, such as the ProSe Relay, uses the sidelink discovery to pair the relay UE and the remote UE for public safety applications. The enhanced device to device (D2D) system uses sidelink discovery to pair eRelay UE and eRemote UE, such as wearable devices and Internet over Thing (IoT) devices. In the new radio (NR) system, sidelink relay extends to vehicle to everything (V2X) applications and public safety. In the current NR network, the remote UE resolves the PC5-S messages, including the discovery messages at the upper layer of the UE protocol stack. Only when the remote UE resolves the PC5-S message the upper layer, can the UE identify the relay UE. This causes unnecessary delay for sidelink UE discovery. Further, although the remote UE can measure a configured resource pool for signal strength, the remote UE does not know the relay UE ID until the PC5-Smessage is resolved during relay UE selection and reselection. This causes unnecessary delay for signal evaluation.

Improvements and enhancements are required for early packet filtering for sidelink UE discovery.

SUMMARY

Apparatus and methods are provided for early packet filtering for sidelink UE discovery. In one novel aspect, the UE puts discovery message information in MAC header of MAC PDU carrying PC5-S discovery message. The receiving UE performs packet filtering based on the MAC layer information. In one embodiment, the UE performs a lower-layer packet filtering at one or more lower layers consisting of the PHY layer and the MAC layer. The UE detects a sidelink UE discovery message in a MAC PDU at the MAC layer based on the lower-layer packet filtering, wherein a discovery indicator is detected at a MAC sub header of the MAC PDU. The UE performs a sidelink UE discovery over a PC5 interface of the UE based on the detected sidelink UE discovery message, wherein the sidelink UE discovery establishes a sidelink connection with a relay UE when the UE is a remote UE and with a remote UE when the UE is a relay UE. In one embodiment, the MAC sub header is a SL-SCH MAC sub header, wherein the discovery indicator is a field with one or more bits indicating a UE discovery message PDU, and wherein the field is one selecting from a new field in the SL-SCH MAC sub header, a reserved field, and an extended field within aV-field of the SL-SCH MAC sub header. In another embodiment, the discovery message type is one selecting from a Discovery Announcement message, a Discovery Solicitation message, and a Discovery Response message. In one embodiment, the UE sidelink discovery message is a Discovery Announcement sent by the relay UE, and wherein a 24-bitsource layer-2 (L2) ID field of the MAC sub header of the MAC PDU is a NR UE ID of the relay UE and a 24-bit destination L2 ID of the MAC sub header of the MAC PDU is a relay service code. In another embodiment, the UE sidelink discovery message is a Discovery Announcement sent by the relay UE, and wherein a second stage sidelink control information (SCI) at the PHY layer comprises an 8-bit LSB of a source L2 ID set to be a part of a NR UE ID of the relay UE and a 16-bit LSB of a destination L2 ID set to be a relay service code. In one embodiment, the UE sidelink discovery message is a Discovery Solicitation sent by the remote UE, and wherein a 24-bitdestination layer-2 (L2) ID field of the MAC sub header of the MAC PDU is a NR UE ID of the relay UE and a 24-bit source L2 ID of the MAC sub header of the MAC PDU is one ID selecting from a NR UE ID of the remote UE, a query code, and a relay service code. In another embodiment, the UE sidelink is one of a Discovery Solicitation sent by the remote UE, and wherein a second stage sidelink control information (SCI) at the PHY layer comprises an 16-bit LSB of a destination L2 ID set to be a part of a NR relay UE ID and a 8-bit LSB of a source L2 ID set to be one ID selecting from a part of a NR UE ID of the remote UE, a query code, and a relay service code. In one embodiment, the UE sidelink discovery message is a Discovery Response sent by the relay UE in response to a Discovery Solicitation sent by the remote UE, and wherein a 24-bitsource layer-2 (L2) ID field of the MAC sub header of the MAC PDU is a part of a NR UE ID of the relay UE and a 24-bit destination L2 ID of the MAC sub header of the MAC PDU is one ID selecting from a part of a NR UE ID of the remote UE, a relay service code, and a response code. In yet another embodiment, the UE sidelink is one of a Discovery Response sent by the relay UE in response to a Discovery Solicitation sent by the remote UE, and wherein a second stage sidelink control information (SCI) at the PHY layer comprises an 8-bit LSB of a source L2 ID set to be a part of a NR relay UE ID and a 16-bit LSB of a destination L2 ID set to be one ID selecting from a part of a NR UE ID of the remote UE, a relay service code, and a response code. In one embodiment, a logic channel identification (LCID) is assigned to the MAC PDU for the UE sidelink discovery message.

This summary does not purport to define the invention. The invention is defined by the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, where like numerals indicate like components, illustrate embodiments of the invention.

Figure 1 is a schematic system diagram illustrating an exemplary wireless network for early packet filtering for sidelink UE discovery in accordance with embodiments of the current invention.

Figure 2 illustrates an exemplary NR wireless system with centralized upper layers of the NR radio interface stacks in accordance with embodiments of the current invention.

Figure 3A illustrates exemplary diagrams for resource allocation for mode A UE sidelink UE discovery with early packet filtering in accordance with embodiments of the current invention.

Figure 3B illustrates exemplary diagrams for resource allocation for mode B UE sidelink UE discovery with early packet filtering in accordance with embodiments of the current invention.

Figure 3C illustrates exemplary diagrams for resource allocation for out-of-network UE sidelink UE discovery with early packet filtering in accordance with embodiments of the current invention.

Figure 4 illustrates exemplary diagrams for early packet filtering handling at the UE protocol stack for UE sidelink UE discovery in accordance with embodiments of the current invention.

Figure 5A illustrates exemplary diagrams of MAC PDU carrying Discovery Announcement message in accordance with embodiments of the current invention.

Figure 5B illustrates exemplary diagrams of MAC PDU and the PHY data carrying Discovery Announcement message in accordance with embodiments of the current invention.

Figure 6A illustrates exemplary diagrams of MAC PDU carrying Discovery Solicitation message in accordance with embodiments of the current invention.

Figure 6B illustrates exemplary diagrams of MAC PDU and the PHY data carrying Discovery Solicitation message in accordance with embodiments of the current invention.

Figure 7A illustrates exemplary diagrams of MAC PDU carrying Discovery Response message in accordance with embodiments of the current invention.

Figure 7B illustrates exemplary diagrams of MAC PDU and the PHY data carrying Discovery Response message in accordance with embodiments of the current invention.

Figure 8 illustrates an exemplary flow chart for the lower-layer packet filtering for UE sidelink UE discovery in accordance with embodiments of the current invention.

DETAILED DESCRIPTION

Reference will now be made in detail to some embodiments of the invention, examples of which are illustrated in the accompanying drawings.

Figure 1 is a schematic system diagram illustrating an exemplary wireless network for early packet filtering for sidelink UE discovery in accordance with embodiments of the current invention. Wireless system 100 includes one or more fixed base infrastructure units forming a network distributed over a geographical region. The base unit may also be referred to as an access point, an access terminal, a base station, a Node-B, an eNode-B (eNB) , a gNB, or by other terminology used in the art. The network can be a homogeneous network or heterogeneous network, which can be deployed with the same frequency or different frequency. gNB 101, gNB 102, and gNB 103 are base stations in the NR network, the serving area of which may or may not overlap with each other. Backhaul connections such as 131, 132, and 133, connect the non-co-located receiving base units, such as gNB 101, 102, and 103. These backhaul connections can be either ideal or non-ideal. gNB 101 is connected with gNB 102 via Xnr interface 131 and is connected with gNB 103 via Xnr interface 132. gNB 102 is connected with gNB 103 via Xnr interface 133.

Wireless network 100 also includes multiple communication devices or mobile stations, such user equipments (UEs) such as

UEs

111, 112, 113, 114, 117, 118, 121, 122, 123, 125, and 128. Communication devices or mobile stations in wireless network 100 may also refer to devices with wireless connectivity in a vehicle, such as mobile devices 118, 117, and 128. The exemplary mobile devices in wireless network 100 have sidelink capabilities. The mobile devices can establish one or more connections with one or more base stations, such as gNB 101, 102, and 103. The mobile device may also be out of connection with the base stations with its access links but can transmit and receive data packets with another one or more other mobile stations or with one or more base stations through L2-based sidelink relay.

In one novel aspect, on-demand system information is sent to the remote UE through a configuredL2-based sidelink relay. In one embodiment, the sidelink relay UE-to-Network one-hop relay using sidelink is configured. A remote UE 111 and gNB 103 forms an end-to-end path 181 through a sidelink relay with a relay UE 121. End-to-end path 181 includes an access link 135 between gNB 103 and relay UE 121 and a sidelink 171 between remote UE 111 and relay UE 121. In another embodiment, the sidelink relay for the on-demand SI is the L2-based UE-to-Network multi-hop relay using sidelink. A remote UE 112 and gNB 102 forms an end-to-end path 182 through a L2-based sidelink relay with a relay UE 122 and another relay UE 123. End-to-end path 182 includes an access link 136 between gNB 102 and relay UE 122, sidelink 172 between relay UE 122 and relay UE 123, and sidelink 173 between remote UE 112 and relay UE 123. In yet another embodiment, a relay mobile device is configured with multiple remote mobile devices or multiple end node mobile devices. A relay UE 128, with an access link 137 to gNB 101 is configured with two remote UEs 117 and 118 through

sidelink

175 and 176, respectively. In other embodiments, a relay mobile device can be configured for multiple UE-to-UE relay paths. Different links are established for the illustrated relay paths. An access link is a link between a base station, such as gNB and a mobile device, such as a UE. The UE can be a remote UE or a relay UE. The access link includes both the uplink (UL) and the downlink (DL) between the base station and the mobile device. The interface for the access link is a NR Uu interface. In one embodiment, the remote UE also establishes access link with a base station. A side link is a link between two mobile devices and uses PC5 interface. The sidelink can be a link between a remote UE /end-node UE and a relay UE or a link between two relay mobile devices /UEs for the multi -hop relay. The end-to-end link for a relay path can be a link between two end-node mobile devices for a UE-to-UE relay or a base station to mobile device for a UE-to-Network relay. An Xn link is the backhaul link between two base stations, such gNBs using the Xn interface. In one embodiment, candidate relay UE information is transmitted to the base station via the Xn link. In one embodiment, the UE sidelink relay applies to out-of-network UE(s) . Out-of-network UE 125 is a relay UE connecting with out-of-network remote UEs 113 and 114 through

sidelink

177 and 178, respectively. The end-to-end relay path 183 includes the

relay link

177 and 178. The out-of -network relay applies to one or more UEs in the relay path not having access link to the network and is out-of-network. One or more UEs in the out-of-network UE sidelink relay, in some embodiments, have access links with the network. For out-of-network UE sidelink relay with all UEs in the relay path being out-of-network, preconfigured resources are used for sidelink establishment.

Figure 1 further illustrates simplified block diagrams of a base station and a mobile device/UE for early packet filtering for UE sidelink relay. gNB 103 has an antenna 156, which transmits and receives radio signals. An RF transceiver circuit 153, coupled with the antenna, receives RF signals from antenna156, converts them to baseband signals, and sends them to processor 152. RF transceiver 153 also converts received baseband signals from processor152, converts them to RF signals, and sends out to antenna 156. Processor 152 processes the received baseband signals and invokes different functional modules to perform features in gNB 103. Memory 151 stores program instructions and data 154 to control the operations of gNB 103. gNB 103 also includes a set of control modules 155 that carry out functional tasks to communicate with mobile stations.

A UE can be a remote UE, such as UE 111, or a relay UE, such as UE 121. THE UE has an antenna 165, which transmits and receives radio signals. An RF transceiver circuit 163, coupled with the antenna, receives RF signals from antenna165, converts them to baseband signals, and sends them to processor 162. In one embodiment, the RF transceiver may comprise two RF modules (not shown) . A first RF module is used for HF transmitting and receiving, and the other RF module is used for different frequency bands transmitting and receiving, which is different from the HF transceiver. RF transceiver 163 also converts received baseband signals from processor162, converts them to RF signals, and sends out to antenna 165. Processor 162 processes the received baseband signals and invokes different functional modules to perform features in the UE. Memory 161 stores program instructions and data 164 to control the operations of the UE. Antenna 165 sends uplink transmission and receives downlink transmissions to/from antenna 156 of gNB 103.

The UE also includes a set of control modules that carry out functional tasks. These control modules can be implemented by circuits, software, firmware, or a combination of them. A lower-layer filtering circuit 191 performs a lower-layer packet filtering, wherein the lower-layer packet filtering is performed at one or more UE protocol layers consisting a PHY layer and a MAC layer. A discovery indication circuit 192 detects a sidelink UE discovery message in a MAC packet data unit (PDU) at the MAC layer based on the lower-layer packet filtering, wherein a discovery indicator is detected at a MAC sub header of the MAC PDU. A discovery circuit 193 performs a sidelink UE discovery over a PC5 interface of the UE based on the detected sidelink UE discovery message, wherein the sidelink UE discovery establishes a sidelink connection with a relay UE when the UE is a remote UE and with a remote UE when the UE is a relay UE.

Figure 2 illustrates an exemplary NR wireless system with centralized upper layers of the NR radio interface stacks in accordance with embodiments of the current invention. Different protocol split options between central unit (CU) and distributed unit (DU) of gNB nodes may be possible. The functional split between the CU and DU of gNB nodes may depend on the transport layer. Low performance transport between the CU and DU of gNB nodes can enable the higher protocol layers of the NR radio stacks to be supported in the CU, since the higher protocol layers have lower performance requirements on the transport layer in terms of bandwidth, delay, synchronization and jitter. In one embodiment, SDAP and PDCP layer are located in the CU, while RLC, MAC and PHY layers are located in the DU. A Core unit 201 is connected with one central unit 211 with gNB upper layer 252. In one embodiment 250, gNB upper layer 252 includes the PDCP layer and optionally the SDAP layer. Central unit 211 is connected with distributed

units

221, 222, and 221. Distributed

units

221, 222, and 223 each corresponds to a

cell

231, 232, and 233, respectively. The DUs, such as 221, 222 and 223 includes gNB lower layers 251. In one embodiment, gNB lower layers 251 include the PHY, MAC and the RLC layers. In another embodiment 260, each gNB has the protocol stacks 261 including SDAP, PDCP, RLC, MAC and PHY layers.

In one embodiment, the on-demand SI update is delivered to a remote UE through a UE-to-Network sidelink relay path. The UE-to-Network sidelink relay can be configured to be one-hop relay or multi-hop relay. Further, the UEs perform early packet filtering for UE discovery.

In one novel aspect, early packet filtering is performed to get relay UE information for sidelink UE discovery. There are two modes for the sidelink UE discovery. In a mode A procedure, the relay UE transmits Discovery Announcement message for the remote UE to discover the available relay UEs. In a mode B procedure, the remote UE transmits Discovery Solicitation message for the relay UE to response. The radio resource allocation for mode A and mode B are illustrated below. In other embodiments, out-of-network UE discovery performs in either mode A or mode B and uses a preconfigured resource pool for sidelink UE discovery.

Figure 3A illustrates exemplary diagrams for resource allocation for mode A 300 UE in sidelink UE discovery with early packet filtering in accordance with embodiments of the current invention. A relay UE 303 has an access link 312 with a gNB 302. Remote UE 301 and relay UE 303 performs UE sidelink UE discovery to establish sidelink 311 between relay UE 303 and remote UE 301. In one embodiment, mode A UE discovery is used. Relay UE 303 uses RRC signal through access link 312 to get the permission and the corresponding transmission resource pool for sidelink discovery message. Relay UE 303 uses the resource in the transmission pool for the Discovery Announcement message 315.

Figure 3B illustrates exemplary diagrams for resource allocation for mode B 320 UE in sidelink UE discovery with early packet filtering in accordance with embodiments of the current invention. A relay UE 323 has an access link 332 with a gNB 322. Remote UE 321 has an access link 333 with gNB 322. Remote UE 321 and relay UE 323 performs UE sidelink UE discovery to establish sidelink 331 between relay UE 323 and remote UE 321. In one embodiment, mode B UE discovery is used. Remote UE 321 uses RRC signal through access link 333 to get the permission and the corresponding transmission resource pool for sidelink discovery message. Relay UE 323 uses the resource in the transmission pool for the Discovery Solicitation message 335.

Figure 3C illustrates exemplary diagrams for resource allocation for out-of-network UE in sidelink UE discovery with early packet filtering in accordance with embodiments of the current invention. In one embodiment, both the remote UE and the relay UE are out-of-network UE 350. The PC5 interface for sidelink communication between the remote UE and relay UE is configured. Remote UE 351, remote UE 352, and relay UE 353 are all out of cellular network coverage. To establish sidelink 361 between relay UE 353 and remote UE 351 and/or sidelink 362 between relay UE 353 and remote UE 352, resources for discovery messages are selected. The out-of-network UEs can use mode A or mode B for sidelink UE discovery. For a mode A discovery, relay UE 353 transmits Discovery Announcement message 365. For a mode B discovery, remote UE 351 and remote UE 352 transmits

Discovery Solicitation message

366 and 367, respectively. In one embodiment, resource for sidelink discovery is preconfigured. The remote UE and the relay UE perform sensing before any transmission. After the UE selects a resource for sidelink transmission, the UE uses the selected resource to transmit discovery messages.

Figure 4 illustrates exemplary diagrams for early packet filtering handling at the UE protocol stack for sidelink UE discovery in accordance with embodiments of the current invention. A UE protocol stack has lower layer stack 401 and upper layer stack 402. Lower layer stack 401 includes physical (PHY) layer 430 and the MAC layer 420. Upper layer stack 402 includes radio link control (RLC) layer 430, packet data convergence protocol (PDCP) layer 440 and application layer 450, such as the IP layer and the service data adaptation protocol (SDAP) layer. Lower-layer packet filtering is used for sidelink UE discovery. The sidelink UE discovery uses discovery messages. The discovery messages include the Discovery Announcement message sent by the relay UE, the Discovery Solicitation message sent by the remote UE, and the Discovery Response message sent by the relay UE in response to the Discovery Solicitation message. In one novel aspect, the discovery message is filtered at lower layers including the PHY layer 410 and MAC layer 420. A discovery message indicator is set at the MAC layer in a MAC header. In one embodiment, the discovery message parameters are set in the MAC header of the MAC layer. In another embodiment, the discovery message parameters are set in the MAC layer and the PHY layer. The discovery message at the APP layer is a special type of PDCP service data unit (SDU) and is delivered to the PDCP entity for transmission at the sidelink. U-mode compression mode is used for this PDCP SDU if compression is enabled. When the PDCP entity delivers the PDCP PDU carrying discovery message to the RLC entity for transmission at sidelink, the RLC entity does not segment the PDU to enable fast transmission at the lower layer. The Unacknowledged Mode (UM) mode is used for the transmission of PDCP PDU carrying discovery messages at RLC entity. During logic channel prioritization (LCP) procedure, the special logical channel for transmitting discovery message PDU has the highest priority. In one embodiment, the SL-SCH logic channel is assigned.

In one novel aspect, the NR relay UE ID and its corresponding relay service code are set in the MAC header of MAC PDU carrying the discovery message. The receiving UE of the discovery message performs packet filtering based on the relay UE ID and its corresponding relay service code at the MAC layer when the MAC PDU is decoded. Relay UE ID corresponds to the 24-bit Layer 2 (L2) source ID as specified by 3GPP NR V2X at Rel-16. Relay UE ID is a link layer identifier that is used for direct communication and is associated with a relay service code. A UE-to-Network relay has a distinct relay UE ID for each relay service code. For support of multiple packet data network (PDN) connections, the UE-to-Network relay is assigned a different relay UE ID for each PDN connection. The relay service code is the parameter identifying a connectivity service the UE-to-Network relay provides to V2X or Public Safety applications. The relay service code is used to indicate the relay service code for which the UE is requesting keys.

Figure 5A illustrates exemplary diagrams of MAC PDU carrying Discovery Announcement message in accordance with embodiments of the current invention. A relay UE 503 and a remote UE 501 establishes a sidelink through a sidelink UE discovery procedure. In a mode A procedure, relay UE 503 transmits a Discovery Announcement message 510 and enables lower-layer filtering at lower layers PHY 511 and MAC 512. In one embodiment, for the MAC PDU carrying the Discovery Announcement, the SRC and DST fields within MAC header includes the 24-bit long Source Layer-2 ID and Destination Layer-2 ID. The Source Layer-2 ID is set to be the NR relay UE ID. The Destination Layer-2 ID is set to be therelay service code. The MAC header for the logical channel carrying the Discovery Announcement message is to enable MAC layer packet filtering. The V-field of the MAC header is a MAC PDU format version. A specific format version number is filled in the V-field or as a separate field to indicate that the MAC PDU is for relay purpose, or for relay discovery purpose. The SRC and DST fields within MAC header include the 24-bit long Source L2 ID and Destination L2 ID. The Source L2 ID is set to be the NR relay UE ID. The Destination L2 ID is set to be the relay service code.

Figure 5B illustrates exemplary diagrams of MAC PDU and the PHY data carrying Discovery Announcement message in accordance with embodiments of the current invention. In a mode A procedure, relay UE 503 transmits a Discovery Announcement message 520 and enables lower-layer filtering at lower layers PHY 521 and MAC 522. In one embodiment, for the MAC PDU carrying the Discovery Announcement, the SRC and DST fields within MAC header includes part of the 24-bit long Source Layer-2 ID and Destination Layer-2 ID. The MAC header for the logical channel carrying the Discovery Announcement message is to enable MAC layer packet filtering. The V-field of the MAC header is a MAC PDU format version. A specific format version number is filled in the V-field or as a separate field to indicate that the MAC PDU is for relay purpose, or for relay discovery purpose. The SRC field of the MAC header includes sixteen bits MSBof the source L2 ID, which is set to be the NR relay ID. The DST field MAC header of the MAC header includes eight bits MSB of the destination L2 ID, which is set to be the relay service code. The MAC PDU carrying the Discovery announcement is delivered to the physical layer to generate a corresponding transmission. The physical layer uses physical sidelink control channel (PSCCH) /physical sidelink shared channel (PSSCH) to transmit this MAC PDU. The PSCCH carries the first stage sidelink control information (SCI) indicating the resources of PSSCH that carries both the second stage SCI and the data (i.e. the MAC PDU carrying Discovery Announcement) . In one embodiment, the second stage SCI includesdiscovery message parameters to enable physical packet filtering. The SRC field of the second stage SCI includes eight bits LSBof the source L2 ID, which is set to be the NR relay ID. The DST field second stage SCI includes sixteen bits LSB of the destination L2 ID, which is set to be the relay service code.

Figure 6A illustrates exemplary diagrams of MAC PDU carrying Discovery Solicitation message in accordance with embodiments of the current invention. A relay UE 603 and a remote UE 601 establishes a sidelink through a sidelink UE discovery procedure. In a mode B procedure, remote UE 601 transmits a Discovery Solicitation message 610 and enables lower-layer filtering at lower layers PHY 611 and MAC 612. The contents of remote UE Discovery Solicitation includes the identifiers of the Remote UE: Discoverer Info, relay service code and relay UE ID. Additionally, the NR Remote UE ID may be included. The Discoverer Info provides the information about Discoverer user and it may include a query code as defined by 3GPP TS23.003. In one embodiment, for the MAC PDU carrying the Discovery Solicitation message, the SRC and DST fields within MAC header includes the 24-bit long Source Layer-2 ID and Destination Layer-2 ID. The Source Layer-2 ID is set to be theremote UE ID, or the relay service code, or the query code. The Destination Layer-2 ID is set to be therelay UE ID. The MAC header for the logical channel carrying the Discovery Solicitation message is to enable MAC layer packet filtering. The V-field of the MAC header is a MAC PDU format version. A specific format version number is filled in the V-field or as a separate field to indicate that the MAC PDU is for relay purpose, or for relay discovery purpose.

Figure 6B illustrates exemplary diagrams of MAC PDU and the PHY data carrying Discovery Solicitation message in accordance with embodiments of the current invention. In a mode B procedure, remote UE 601 transmits a Discovery Solicitation message 620 and enables lower-layer filtering at lower layers PHY 621 and MAC 622. The contents of remote UE Discovery Solicitation includes the identifiers of the Remote UE: Discoverer Info, relay service code and relay UE ID. Additionally, the NR Remote UE ID may be included. The Discoverer Info provides the information about Discoverer user and it may include a query code as defined by 3GPP TS23.003. In one embodiment, for the MAC PDU carrying the Discovery Solicitation, the SRC and DST fields within MAC header includes part of the 24-bit long Source Layer-2 ID and Destination Layer-2 ID. The MAC header for the logical channel carrying the Discovery Solicitation message is to enable MAC layer packet filtering. The V-field of the MAC header is a MAC PDU format version. A specific format version number is filled in the V-field or as a separate field to indicate that the MAC PDU is for relay purpose, or for relay discovery purpose. The SRC field of the MAC header includes sixteen bits MSBof the source L2 ID, which is set to be the relay service code, or the remote UE ID, or the query code. The DST field MAC header of the MAC header includes eight bits MSB of the destination L2 ID, which is set to be the NR relay UE ID. The MAC PDU carrying the Discovery announcement is delivered to the physical layer to generate a corresponding transmission. The physical layer uses physical sidelink control channel (PSCCH) /physical sidelink shared channel (PSSCH) to transmit this MAC PDU. The PSCCH carries the first stage sidelink control information (SCI) indicating the resources of PSSCH that carries both the second stage SCI and the data (i.e. the MAC PDU carrying Discovery Solicitation) . In one embodiment, the second stage SCI includes discovery message parameters to enable physical packet filtering. The SRC field of the second stage SCI includes eight bits LSBof the source L2 ID, which is set to be the relay service code, or the remote UE ID, or the query code. The DST field second stage SCI includes sixteen bits LSB of the destination L2 ID, which is set to be the NR relay UE ID.

Figure 7A illustrates exemplary diagrams of MAC PDU carrying Discovery Response message in accordance with embodiments of the current invention. A relay UE 703 and a remote UE 701 establishes a sidelink through a sidelink UE discovery procedure. In a mode B procedure, relay UE 703 transmits a Discovery Response message 710 and enables lower-layer filtering at lower layers PHY 711 and MAC 712. Relay UE 703 monitors a Discovery Solicitation message from a remote UE according to the RX resource pool configuration. In one embodiment, When the query code in the Discovery Solicitation message matches the discovery Query filter (s) within the relay UE, relay UE 703 sends the Discovery Response with a response code. Relay UE 703 sends Discovery Response message at sidelink only when the discovery mode is configured as mode B. The contents of Discovery Response include the identifiers of the relay UE: discoveree info, relay service code and relay UE ID. Thediscovereeinfo provides the information about Discoveree user and it may include the response code. In one embodiment, for the MAC PDU carrying the Discovery Response message, the SRC and DST fields within MAC header includes the 24-bit long Source Layer-2 ID and Destination Layer-2 ID. The Source Layer-2 ID is set to be the relay UE ID. The Destination Layer-2 ID is set to be theremote UE ID, or the relay service code, or the response code. The MAC header for the logical channel carrying the Discovery Response message is to enable MAC layer packet filtering. The V-field of the MAC header is a MAC PDU format version. A specific format version number is filled in the V-field or as a separate field to indicate that the MAC PDU is for relay purpose, or for relay discovery purpose.

Figure 7B illustrates exemplary diagrams of MAC PDU and the PHY data carrying Discovery Response message in accordance with embodiments of the current invention. A relay UE 703 and a remote UE 701 establishes a sidelink through a sidelink UE discovery procedure. In a mode B procedure, relay UE 703 transmits a Discovery Response message 720 and enables lower-layer filtering at lower layers PHY 721 and MAC 722. In one embodiment, for the MAC PDU carrying the Discovery Response, the SRC and DST fields within MAC header includes part of the 24-bit long Source Layer-2 ID and Destination Layer-2 ID. The MAC header for the logical channel carrying the Discovery Response message is to enable MAC layer packet filtering. The V-field of the MAC header is a MAC PDU format version. A specific format version number is filled in the V-field or as a separate field to indicate that the MAC PDU is for relay purpose, or for relay discovery purpose. The SRC field of the MAC header includes sixteen bits MSBof the source L2 ID, which is set to be the NR relay UE ID. The DST field MAC header of the MAC header includes eight bits MSB of the destination L2 ID, which is set to be the relay service code, or the remote UE ID, or the response code. The MAC PDU carrying the Discovery announcement is delivered to the physical layer to generate a corresponding transmission. The physical layer uses physical sidelink control channel (PSCCH) /physical sidelink shared channel (PSSCH) to transmit this MAC PDU. The PSCCH carries the first stage sidelink control information (SCI) indicating the resources of PSSCH that carries both the second stage SCI and the data (i.e. the MAC PDU carrying Discovery Response) . In one embodiment, the second stage SCI includes discovery message parameters to enable physical packet filtering. The SRC field of the second stage SCI includes eight bits LSBof the source L2 ID, which is set to be the NR relay UE ID.The DST field second stage SCI includes sixteen bits LSB of the destination L2 ID, which is set to be the relay service code, or the remote UE ID, or the response code.

Figure 8 illustrates an exemplary flow chart for the early packet filtering for sidelink UE discovery in accordance with embodiments of the current invention. At step 801, a user equipment (UE) performs a lower-layer packet filtering by in a new radio (NR) wireless network, wherein the lower-layer packet filtering is performed at one or more UE protocol layers consisting a PHY layer and a MAC layer. At step 802, the UE detects a sidelink UE discovery message in a MAC packet data unit (PDU) at the MAC layer based on the lower-layer packet filtering, wherein a discovery indicator is detected at a MAC sub header of the MAC PDU. At step 803, the UE performs a sidelink UE discovery over a PC5 interface of the UE based on the detected sidelink UE discovery message, wherein the sidelink UE discovery establishes a sidelink connection with a relay UE when the UE is a remote UE and with a remote UE when the UE is a relay UE.

Although the present invention has been described in connection with certain specific embodiments for instructional purposes, the present invention is not limited thereto. Accordingly, various modifications, adaptations, and combinations of various features of the described embodiments can be practiced without departing from the scope of the invention as set forth in the claims.

Claims

A method comprising:

performing a lower-layer packet filtering by a user equipment (UE) in a new radio (NR) wireless network, wherein the lower-layer packet filtering is performed at one or more UE protocol layers consisting a PHY layer and a MAC layer;

detecting a sidelink UE discovery message in a MAC packet data unit (PDU) at the MAC layer based on the lower-layer packet filtering, wherein a discovery indicator is detected at a MAC sub header of the MAC PDU; and

performing a sidelink UE discovery over a PC5 interface of the UE based on the detected sidelink UE discovery message, wherein the sidelink UE discovery establishes a sidelink connection with a relay UE when the UE is a remote UE and with a remote UE when the UE is a relay UE.
The method of claim 1, wherein the MAC sub header is a sidelink (SL) shared channel (SCH) MAC sub header, and wherein the discovery indicator is a field with one or more bits indicating a UE discovery message PDU, and wherein the field is one selecting from a new field in the SL-SCH MAC sub header, a reserved field, and an extended field within aV-field of the SL-SCH MAC sub header.
The method of claim 1, wherein the discovery message type is one selecting from a Discovery Announcement message, a Discovery Solicitation message, and a Discovery Response message.
The method of claim 3, wherein the UE sidelink discovery message is a Discovery Announcement sent by the relay UE, and wherein a 24-bitsource layer-2 (L2) ID field of the MAC sub header of the MAC PDU is a NR UE ID of the relay UE and a 24-bit destination L2 ID of the MAC sub header of the MAC PDU is a relay service code.
The method of claim 3, wherein the UE sidelink discovery message is a Discovery Announcement sent by the relay UE, and wherein a second stage sidelink control information (SCI) at the PHY layer comprises an 8-bit LSB of a source L2 ID set to be a part of a NRUE ID of the relay UE and a 16-bit LSB of a destination L2 ID set to be a relay service code.
The method of claim 3, wherein the UE sidelink discovery message is a Discovery Solicitation sent by the remote UE, and wherein a 24-bitdestination layer-2 (L2) ID field of the MAC sub header of the MAC PDU is a NR UE ID of the relay UE and a 24-bit source L2 ID of the MAC sub header of the MAC PDU is one ID selecting from a NR UE ID of the remote UE, a query code, and a relay service code.
The method of claim 3, wherein the UE sidelink is one of a Discovery Solicitation sent by the remote UE, and wherein a second stage sidelink control information (SCI) at the PHY layer comprises an 16-bit LSB of a destination L2 ID set to be a part of a NR relay UE ID and a 8-bit LSB of a source L2 ID set to be one ID selecting from a part of a NR UE ID of the remote UE, a query code, and a relay service code.
The method of claim 3, wherein the UE sidelink discovery message is a Discovery Response sent by the relay UE in response to a Discovery Solicitation sent by the remote UE, and wherein a 24-bitsource layer-2 (L2) ID field of the MAC sub header of the MAC PDU is a part of a NR UE ID of the relay UE and a 24-bit destination L2 ID of the MAC sub header of the MAC PDU is one ID selecting from a part of a NR UE ID of the remote UE, a relay service code, and a response code.
The method of claim 3, wherein the UE sidelink is one of a Discovery Response sent by the relay UE in response to a Discovery Solicitation sent by the remote UE, and wherein a second stage sidelink control information (SCI) at the PHY layer comprises an 8-bit LSB of a source L2 ID set to be a part of a NR relay UE ID and a 16-bit LSB of a destination L2 ID set to be one ID selecting from a part of a NR UE ID of the remote UE, a relay service code, and a response code.
The method of claim 1, wherein a logic channel identification (LCID) is assigned to the MAC PDU for the UE sidelink discovery message.
A user equipment (UE) , comprising:

a transceiver that transmits and receives radio frequency (RF) signal in a new radio (NR) wireless network;

a lower-layer filtering circuit that performs a lower-layer packet filtering, wherein the lower-layer packet filtering is performed at one or more UE protocol layers consisting a PHY layer and a MAC layer;

a discovery indication circuit that detects a sidelink UE discovery message in a MAC packet data unit (PDU) at the MAC layer based on the lower-layer packet filtering, wherein a discovery indicator is detected at a MAC sub header of the MAC PDU; and

a discovery circuit that performs a sidelink UE discovery over a PC5 interface of the UE based on the detected sidelink UE discovery message, wherein the sidelink UE discovery establishes a sidelink connection with a relay UE when the UE is a remote UE and with a remote UE when the UE is a relay UE.
The UE of claim 11, wherein the MAC sub header is a sidelink (SL) shared channel (SCH) MAC sub header, and wherein the discovery indicator is a field with one or more bits indicating a UE discovery message PDU, and wherein the field is one selecting from a new field in the SL-SCH MAC sub header, a reserved field, and an extended field within aV-field of the SL-SCH MAC sub header.
The UE of claim 11, wherein the discovery message type is one selecting from a Discovery Announcement message, a Discovery Solicitation message, and a Discovery Response message.
The UE of claim 13, wherein the UE sidelink discovery message is a Discovery Announcement sent by the relay UE, and wherein a 24-bitsource layer-2 (L2) ID field of the MAC sub header of the MAC PDU is a NR UE ID of the relay UE and a 24-bit destination L2 ID of the MAC sub header of the MAC PDU is a relay service code.
The UE of claim 13, wherein the UE sidelink discovery message is a Discovery Announcement sent by the relay UE, and wherein a second stage sidelink control information (SCI) at the PHY layer comprises an 8-bit LSB of a source L2 ID set to be a part of a NR UE ID of the relay UE and a 16-bit LSB of a destination L2 ID set to be a relay service code.
The UE of claim 13, wherein the UE sidelink discovery message is a Discovery Solicitation sent by the remote UE, and wherein a 24-bitdestination layer-2 (L2) ID field of the MAC sub header of the MAC PDU is a NR UE ID of the relay UE and a 24-bit source L2 ID of the MAC sub header of the MAC PDU is one ID selecting from a NR UE ID of the remote UE, a query code, and a relay service code.
The UE of claim 13, wherein the UE sidelink is one of a Discovery Solicitation sent by the remote UE, and wherein a second stage sidelink control information (SCI) at the PHY layer comprises an 16-bit LSB of a destination L2 ID set to be a part of a NR relay UE ID and a 8-bit LSB of a source L2 ID set to be one ID selecting from a part of a NR UE ID of the remote UE, a query code, and a relay service code.
The UE of claim 13, wherein the UE sidelink discovery message is a Discovery Response sent by the relay UE in response to a Discovery Solicitation sent by the remote UE, and wherein a 24-bitsource layer-2 (L2) ID field of the MAC sub header of the MAC PDU is a part of a NR UE ID of the relay UE and a 24-bit destination L2 ID of the MAC sub header of the MAC PDU is one ID selecting from a part of a NR UE ID of the remote UE, a relay service code, and a response code.
The UE of claim 13, wherein the UE sidelink is one of a Discovery Response sent by the relay UE in response to a Discovery Solicitation sent by the remote UE, and wherein a second stage sidelink control information (SCI) at the PHY layer comprises an 8-bit LSB of a source L2 ID set to be a part of a NR relay UE ID and a 16-bit LSB of a destination L2 ID set to be one ID selecting from a part of a NR UE ID of the remote UE, a relay service code, and a response code.
The UE of claim 11, wherein a logic channel identification (LCID) is assigned to the MAC PDU for the UE sidelink discovery message.