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US-12628209-B2 - Layer 2 relay protocols and mobility relay method

US12628209B2US 12628209 B2US12628209 B2US 12628209B2US-12628209-B2

Abstract

There is are provided methods and apparatus relating to layer 2 relaying and mobility using a sidelink interface, including a remote user equipment (UE) for use in a wireless communication network, the UE comprising: a device to network (D2N) entity, a device to device (D2D) entity, and control logic to: receive a service data unit derived from an IP packet direct the service data unit to the D2N entity for communication with an eNB using a Uu interface in a first mode of operation, and direct the service data unit to the D2D entity for communication with the eNB via a first relay UE using a sidelink interface in a second, relay, mode of operation.

Inventors

  • Richard Burbidge
  • Sangeetha L. Bangolae
  • Youn Hyoung Heo
  • Kyeongin Jeong
  • Jaemin HAN
  • Mo-Han Fong

Assignees

  • APPLE INC.

Dates

Publication Date
20260512
Application Date
20220520

Claims (12)

  1. 1 . A remote user equipment (UE) for use in a wireless communication network, the remote UE comprising: a memory; and one or more processors coupled to the memory, the one or more processors configured to, when executing instructions stored in the memory, cause the UE to: receive, from a base station, a radio resource control (RRC) connection reconfiguration message comprising a relay UE identifier of a relay UE, wherein the relay UE serves as a relay between the remote UE and the base station; establish a connection with the relay UE based on the relay UE identifier; determine to communicate a layer-2 (L2) packet data unit (PDU) to the base station via a relay UE, wherein the remote UE communicates with the relay UE using a sidelink network interface; and transmit, to the relay UE via the sidelink network interface, the L2 PDU based on a mapping between: (i) a radio bearer identifier of a radio bearer between the base station and the remote UE, and (ii) a logical channel identifier used on the sidelink network interface.
  2. 2 . The remote UE of claim 1 , the one or more processors further configured to: include in the L2 PDU a remote UE identifier of the remote.
  3. 3 . The remote UE of claim 2 , wherein a plurality of remote UEs are configured to communicate with the relay UE, and wherein the remote UE identifier uniquely identifies the remote UE within the plurality of remote UEs communicating with the relay UE.
  4. 4 . The remote UE of claim 1 , wherein the relay UE is a first relay UE, and wherein the one or more processors are further configured to: determine that the remote UE is within proximity of a second relay UE that is closer to the remote UE than the first relay UE; and responsively establish a connection with the second relay UE by transmitting a Direct Communication Request message to the second relay UE.
  5. 5 . The remote UE of claim 4 , the one or more processors further configured to: transmit an indication to the first relay UE to indicate a relay path has been switched to the second relay UE.
  6. 6 . The remote UE of claim 1 , wherein the relay UE is a first relay UE, the relay UE identifier is a first relay UE identifier, and the RRC connection reconfiguration message is a first RRC connection reconfiguration message, and wherein the one or more processors further configured to: receive, from the base station, a second RRC connection reconfiguration message comprising a second relay UE identifier of a second relay UE; and establish a connection with the second relay UE based on the second relay UE identifier.
  7. 7 . One or more processors of a remote user equipment (UE), the one or more processors configured to perform operations comprising: receiving, from a base station, a radio resource control (RRC) connection reconfiguration message comprising a relay user equipment (UE) identifier of a relay UE, wherein the relay UE serves as a relay between the remote UE and the base station; establishing a connection with the relay UE based on the relay UE identifier; determining to communicate a layer-2 (L2) packet data unit (PDU) to the base station via a relay UE, wherein the remote UE communicates with the relay UE using a sidelink network interface; and causing transmission, to the relay UE via the sidelink network interface, the L2 PDU based on a mapping between: (i) a radio bearer identifier of a radio bearer between the base station and the remote UE, and (ii) a logical channel identifier used on the sidelink network interface.
  8. 8 . The one or more processors of claim 7 , the operations further comprising: including in the L2 PDU a remote UE identifier of the remote UE.
  9. 9 . The one or more processors of claim 8 , wherein a plurality of remote UEs are configured to communicate with the relay UE, and wherein the remote UE identifier uniquely identifies the remote UE within the plurality of remote UEs communicating with the relay UE.
  10. 10 . The one or more processors of claim 7 , wherein the relay UE is a first relay UE, and wherein the operations further comprise: determining that the remote UE is within proximity of a second relay UE that is closer to the remote UE than the first relay UE; and responsively establishing a connection with the second relay UE by transmitting a Direct Communication Request message to the second relay UE.
  11. 11 . The one or more processors of claim 10 , the operations further comprising: causing transmission of an indication to the first relay UE to indicate a relay path has been switched to the second relay UE.
  12. 12 . The one or more processors of claim 7 , wherein the relay UE is a first relay UE, the relay UE identifier is a first relay UE identifier, and the RRC connection reconfiguration message is a first RRC connection reconfiguration message, and wherein the operations further comprise: receiving, from the base station, a second RRC connection reconfiguration message comprising a second relay UE identifier of a second relay UE; and establishing a connection with the second relay UE based on the second relay UE identifier.

Description

CROSS REFERENCE TO RELATED APPLICATIONS The present application is a continuation of and claims priority to U.S. patent application Ser. No. 16/826,154, filed Mar. 20, 2020, which is a continuation of U.S. patent application Ser. No. 15/745,868, filed Jan. 18, 2018, now U.S. Pat. No. 10,602,550, issued Mar. 24, 2020, which is a national phase entry under 35 U.S.C. § 371 of International Application No. PCT/US2015/000296, filed Dec. 23, 2015, which claims priority to U.S. Provisional Patent Application No. 62/196,138, filed Jul. 23, 2015, entitled “LAYER 2 RELAY PROTOCOLS AND MOBILITY” the entire disclosures of each of which are hereby incorporated by reference. TECHNICAL FIELD Embodiments described herein generally relate to the field of wireless communications and, more particularly, to methods and apparatus for facilitating relaying in a wireless communication system. BACKGROUND It is becoming more important to be able to provide telecommunication services to fixed and mobile subscribers as efficient and inexpensively as possible. Further, the increased use of mobile applications has resulted in much focus on developing wireless systems capable of delivering large amounts of data at high speed. Currently, as part of the Proximity Services (ProSe) capability introduced in Release 13 of the LTE Standards, a basic level of functionality has been described to allow network-to-user equipment (UE) relaying, specifically targeting Public Safety use cases. This functionality relies on the reuse of a sidelink radio communication channel between devices to route traffic at the Internet Protocol (IP) layer. The following functions are supported using this relaying approach: Unicast relaying: Based on one-to-one direct communication between a Remote UE, that is not served by the Evolved Universal Terrestrial Access Network (E-UTRAN), including support for the relaying of unicast traffic (uplink and downlink) between Remote UEs and the E-UTRAN. The ProSe UE-to-Network Relay provides a generic layer 3 (L3) forwarding function that may relay any type of IP traffic that is relevant for public safety communication.Evolved Multimedia Broadcast Multicast Service (eMBMS) relay support: One to many communication, including support for the relaying of eMBMS to Remote UEs served by the UE-to-NW Relay.E-UTRAN Cell Global Identifier (ECGI) announcement: The announcement of the ECGI by a ProSe UE-to-NW Relay allowing remote UEs served by a ProSe UE-to-NW Relay to receive the value of the ECGI of the cell serving the ProSe UE-to-NW Relay. The application of relaying using the sidelink channel to more general use cases, beyond the requirements of Public Security, may require modifications to be made to the currently provided relaying functionality. BRIEF DESCRIPTION OF THE DRAWING Aspects, features and advantages of embodiments of the present invention will become apparent from the following description of the invention in reference to the appended drawings in which like numerals denote like elements and in which: FIG. 1 is diagram of an example wireless network according to various embodiments; FIG. 2 is a block diagram showing the use of sidelink relaying for a public safety use case; FIG. 3a is a block diagram of a protocol stack for L2 relaying above the MAC layer according to some embodiments; FIG. 3b is a block diagram of the protocol stack of FIG. 3a. showing relay routing according to some embodiments; FIG. 4a is a block diagram of a protocol stack for L2 relaying above the RLC layer according to some embodiments; FIG. 4b is a block diagram of the protocol stack of FIG. 4a. showing relay routing according to some embodiments; FIG. 5a is a block diagram of a protocol stack for L2 relaying above the RLC layer with a relaying protocol layer according to some embodiments; FIG. 5b is a block diagram of the protocol stack of FIG. 5a. showing relay routing according to some embodiments; FIG. 6 Illustrates an example relay protocol packet data unit according to some embodiments; FIG. 7 illustrates a MAC subheader format according to some embodiments; FIG. 8 illustrates a MAC packet data unit comprising the subheader format of FIG. 7 according to some embodiments; FIG. 9 illustrates multiplexing of traffic associated with multiple Remote UEs onto a limited number of radio bearers according to some embodiments; FIG. 10a is a block diagram of a protocol stack for layer 2 (L2) relaying above the PDCP layer according to some embodiments FIG. 10b is a block diagram of the protocol stack of FIG. 10a. showing relay routing according to some embodiments; FIG. 11 is a sequence diagram of messaging for Remote UE initiated mobility related signaling according to some embodiments; FIG. 12 is a sequence diagram of messaging for eNB initiated mobility related signaling according to some embodiments; FIG. 13 is a sequence diagram of messaging for eNB initiated mobility related signaling with pre-configuration according to some embodiments; FIG. 14