Method and apparatus for wireless communication
Embodiments of the present disclosure relate to methods and apparatuses for wireless communication. According to some embodiments of the disclosure, a method may include: transmitting, at a first user equipment (UE), a radio resource control (RRC) reconfiguration sidelink via relay message on a sidelink between the first UE and a second UE; and starting a timer associated with the RRC reconfiguration sidelink via relay message. The second UE may act as a relay node and may transfer the received message to a destination UE or base station. The destination UE or base station may response to the first UE before a timer expires.
1 . A method performed by a first user equipment (UE), the method comprising:
transmitting a radio resource control (RRC) setup request message on a sidelink between the first UE and a second UE, wherein the RRC setup request message comprises an identity of the first UE;
starting, based at least in part on transmitting the RRC setup request message, a timer to control establishment of a relay connection between the first UE and the second UE;
receiving, responsive to the RRC setup request message, an RRC setup response message;
stopping the timer based at least in part on receiving the RRC setup response message; and
transmitting an RRC setup complete message, wherein one or more bearers between the second UE and a plurality of UEs comprising the first UE are configured based at least in part on an RRC reconfiguration message between a base station (BS) and the second UE.
2 . The method of claim 1 , wherein a destination of the RRC setup request message is the BS based at least in part on the RRC setup request message failing to indicate the destination of the RRC setup request message.
3 . The method of claim 1 , wherein the RRC setup request message indicates that a destination of the RRC setup request message is either a third UE or the BS.
4 . The method of claim 1 , wherein the RRC setup response message is received based at least in part on a destination of the RRC setup request message being the BS, and wherein the RRC setup complete message comprises the identity of the first UE.
5 . The method of claim 1 , wherein the identity of the first UE is a 5G S-Temporary Mobile Subscription Identifier (5G-S-TMSI), a layer-2 identity, or a reduced layer-2 identity.
6 . A method performed by a second user equipment (UE), the method comprising:
receiving a plurality of radio resource control (RRC) setup request messages on respective sidelinks between a plurality of first UEs and the second UE, wherein the plurality of RRC setup request messages comprises respective identities of the plurality of first UEs;
transmitting, to a base station (BS), the plurality of RRC setup request messages;
receiving, from the BS and responsive to the plurality of RRC setup request messages, an RRC reconfiguration message configuring one or more respective bearers between the plurality of first UEs and the second UE; and
transmitting, to the plurality of first UEs, respective RRC setup response messages based at least in part on the RRC reconfiguration message, wherein a timer to control establishment of a relay connection between the plurality of first UEs and the second UE is started based at least in part on the plurality of RRC setup request messages and is stopped based at least in part on the respective RRC setup response messages.
7 . The method of claim 6 , wherein the respective identities of the plurality of first UEs comprise at least one of a 5G S-Temporary Mobile Subscription Identifier (5G-S-TMSI), a layer-2 identity, or a reduced layer-2 identity.
8 . The method of claim 6 , wherein a destination of respective RRC setup request messages of the plurality of RRC setup request messages is the BS based at least in part on the respective RRC setup request messages failing to indicate the destination.
9 . The method of claim 6 , wherein respective RRC setup request messages of the plurality of RRC setup request messages indicate that a destination of the respective RRC setup request messages is either a third UE or the BS.
10 . The method of claim 6 , wherein respective RRC setup request messages of the plurality of RRC setup request messages are transmitted based at least in part on a destination of the respective RRC setup request messages being the BS, the method further comprises:
receiving, from the plurality of first UEs, respective RRC setup complete messages; and
transmitting, to the BS, the respective RRC setup complete messages, wherein the respective RRC setup complete messages comprise the respective identities of the plurality of first UEs.
11 . The method of claim 6 , wherein the RRC reconfiguration message comprises the respective identities of the plurality of first UEs, and wherein the respective RRC setup response messages are encapsulated in the RRC reconfiguration message.
12 . A method performed by a base station (BS), the method comprising:
receiving, from a second user equipment (UE), a plurality of radio resource control (RRC) setup request messages comprising respective identities of a plurality of first UEs; and
transmitting, to the second UE and responsive to the plurality of RRC setup request messages, an RRC reconfiguration message configuring one or more respective bearers between the plurality of first UEs and the second UE, wherein a timer to control establishment of a relay connection between the plurality of first UEs and the second UE is started based at least in part on the plurality of RRC setup request messages and is stopped based at least in part on respective RRC setup response messages associated with the plurality of first UEs.
13 . The method of claim 12 , wherein the respective identities of the plurality of first UEs comprise at least one of a 5G S-Temporary Mobile Subscription Identifier (5G-S-TMSI), a layer-2 identity or a reduced layer-2 identity.
14 . The method of claim 12 , wherein the plurality of RRC setup request messages is received on a signaling radio bearer 1 (SRB1) or a signaling radio bearer 2 (SRB2), or wherein the plurality of RRC setup request messages is received via an additional BS serving the second UE based at least in part on a master cell group (MCG) failure occurring on a link between the second UE and the additional BS.
15 . The method of claim 12 , wherein the RRC reconfiguration message comprises the respective identities of the plurality of first UEs, and wherein a plurality of RRC setup response messages is encapsulated in the RRC reconfiguration message.
16 . The method of claim 12 , wherein the plurality of RRC setup request messages is received based at least in part on a destination of respective RRC setup request messages of the plurality of RRC setup request messages being the BS, and wherein the method further comprises receiving a plurality of RRC setup complete messages, wherein the plurality of RRC setup complete messages comprises the respective identities of the plurality of first UEs.
17 . A first user equipment (UE) for wireless communication, comprising:
at least one memory; and
at least one processor configured with the at least one memory and operable to cause the first UE to:
transmit a radio resource control (RRC) setup request message on a sidelink between the first UE and a second UE, wherein the RRC setup request message comprises an identity of the first UE;
start, based at least in part on transmitting the RRC setup request message, a timer to control establishment of a relay connection between the first UE and the second UE;
receive, responsive to the RRC setup request message, an RRC setup response message;
stop the timer based at least in part on receiving the RRC setup response message; and
transmit an RRC setup complete message, wherein one or more bearers between the second UE and a plurality of UEs comprising the first UE are configured based at least in part on an RRC reconfiguration message between a base station (BS) and the second UE.
18 . The first UE of claim 17 , wherein a destination of the RRC setup request message is the BS based at least in part on the RRC setup request message failing to indicate the destination of the RRC setup request message.
19 . The first UE of claim 17 , wherein the RRC setup request message indicates that a destination of the RRC setup request message is either a third UE or the BS.
20 . The first UE of claim 17 , wherein an expiry of the timer indicates a radio link failure (RLF) associated with the relay connection between the first UE and the second UE.