Pc5 radio resource control (rrc) sidelink (sl) connection management

Patent metadata

Field	Value
Publication number	US-2023380007-A1
Application number	US-202117913269-A
Country	US
Kind code	A1
Filing date	Apr 1, 2021
Priority date	Apr 9, 2020
Publication date	Nov 23, 2023
Grant date	—

Abstract

A peer user equipment (UE) device maintains an existing Sidelink Radio Bearer (SLRB) configuration to support a first PC5 Radio Resource Control (RRC) sidelink (SL) communication link with a source UE device. The peer UE device receives a request to establish a second PC5 RRC SL communication link with the source UE device and determines that the existing SLRB configuration is required to support the second PC5 RRC SL communication link. The peer UE device releases the first PC5 RRC SL communication link.

First claim

1 . A method performed at a peer user equipment (UE) device comprising:
maintaining a first unicast PC5 Radio Resource Control (RRC) communication link with a source UE device, the first unicast PC5 RRC communication link having an existing Sidelink Radio Bearer (SLRB) configuration; receiving a request to establish a second unicast PC5 RRC communication link with the source UE device; determining the existing SLRB configuration is required to support the second unicast PC5 RRC communication link; and releasing the first unicast PC5 RRC communication link.

2 . The method of claim 1 , wherein the determining the existing SLRB configuration is required for the second RRC PC5 communication link comprises determining that the existing configuration is based on a source layer 2 identifier (L2ID) and a SL logical channel identifier (LCID) identified by the request.

3 . The method of claim 1 , wherein the determining the existing SLRB configuration is required for the second RRC PC5 communication link comprises determining a MAC header of a request message received from the source UE device includes an indication that the first PC5 RRC communication link has been released by the source UE device.

4 . The method of claim 1 , further comprising establishing the second PC5 RRC SL communication link after releasing the first RRC PC5 SL communication link.

5 . The method of claim 1 , further comprising:
after releasing the first RRC PC5 communication link, informing an upper layer protocol function of the release through an access stratum (AS) functional layer of the peer UE device.

6 . The method of claim 1 , wherein the request is transmitted from the source UE device in response to the source UE device releasing the first RRC PC5 communication link.

7 . The method of claim 6 , wherein the source UE device determines to release the first RRC PC5 communication link based on a number of Radio Link Control (RLC) retransmissions.

8 . The method of claim 6 , wherein the request is transmitted from the source UE device after expiration of timer.

9 . The method of claim 8 , wherein the timer is based on a time interval between keep-alive messages received from the peer UE device over the first RRC PC5 communication link.

10 . The method of claim 9 , wherein the timer is an autonomous timer derived at the source UE device based on observation of the time interval between keep-alive messages received from the peer UE device over the first RRC PC5 communication link.

11 . The method of claim 9 , wherein the time interval is communicated between the peer UE device and the source UE device over the first RRC PC5 communication link.

12 . The method of claim 1 , further comprising:
receiving information from a base station; and determining to release the first RRC PC5 communication in response to the information.

13 . The method of claim 12 , wherein the information received from the base station indicates that the source UE device has released the first RRC PC5 communication link.

14 . The method of claim 1 , further comprising:
maintaining a plurality of RRC PC5 communication links with the source UE device, the plurality of RRC PC5 communication links comprising the first RRC PC5 communication link.

15 . A peer user equipment (UE) device comprising:
a transceiver configured to maintain a first unicast PC5 Radio Resource Control (RRC) communication link with a source UE device, the first unicast PC5 RRC communication link having an existing Sidelink Radio Bearer (SLRB) configuration, the transceiver comprising a receiver configured to receive a request to establish a second unicast PC5 RRC communication link with the source UE device; and a controller configured to determine that the existing SLRB configuration is required to support the second unicast PC5 RRC communication link and to release the first unicast PC5 RRC communication link.

16 . The peer UE device of claim 15 , wherein the controller is configured to determine that the existing SLRB configuration is required for the second RRC PC5 communication link by at least determining that the existing configuration is based on a source layer 2 identifier (L2ID) and a SL logical channel identifier (LCID) identified by the request.

17 . The peer UE device of claim 15 , wherein the controller is further configured to establish the second PC5 RRC communication link after releasing the first RRC PC5 communication link.

18 . The peer UE device of claim 15 , the controller further configured to, after releasing the first RRC PC5 communication link, inform an upper layer protocol function of the release through an access stratum (AS) functional layer of the peer UE device.

19 . The peer UE device of claim 15 , wherein the request is transmitted from the source UE device in response to the source UE device releasing the first RRC PC5 communication link.

20 . The peer UE device of claim 19 , wherein the source UE device determines to release the first RRC PC5 communication link based on a number of Radio Link Control (RLC) retransmissions.

21 . The peer UE device of claim 19 , wherein the request is transmitted from the source UE device after expiration of timer.

22 . The peer UE device of claim 21 , wherein the timer is based on a time interval between keep-alive messages received from the peer UE device over the first RRC PC5 communication link.

23 . The peer UE device of claim 22 , wherein the timer is an autonomous timer derived at the source UE device based on observation of the time interval between keep-alive messages received from the peer UE device over the first RRC PC5 communication link.

24 . The peer UE device of claim 22 , wherein the time interval is communicated between the peer UE device and the source UE device over the first RRC PC5 communication link.

25 . The peer UE device of claim 15 , wherein the receiver is configured to receive information from a base station and the controller is configured to release the first RRC PC5 communication in response to the information.

26 . The peer UE device of claim 25 , wherein the information received from the base station indicates that the source UE device has released the first RRC PC5 communication link.

27 . The peer UE device of claim 15 , wherein the transceiver is configured to maintain a plurality of RRC PC5 communication links with the source UE device, the plurality of RRC PC5 communication links comprising the first RRC PC5 communication link.

Assignees

• Kyocera Corp

Inventors

• Chang Henry
• Fujishiro Masato

Classifications

• H04W36/037

  by reducing handover delay, e.g. latency · CPC title

• H04W76/30 Primary

  Connection release · CPC title

• H04W76/25

  Maintenance of established connections · CPC title

• H04W92/18

  between terminal devices · CPC title

• H04W76/23 Primary

  Manipulation of direct-mode connections · CPC title