Method and system to enhance RRC re-establishment procedure in NR access network
Embodiments herein provide a method for handling a RRC re-establishment procedure in a wireless network by a network apparatus. The method includes detecting a radio link failure at a UE in the wireless network; receiving an RRC re-establishment request message from the UE; sending a downlink RRC re-establishment message and facilitating the allocation of an uplink grant to the UE; receiving a RRC re-establishment complete message from the UE on the allocated uplink grant resource. The method can be used to improve RRC re-establishment procedure completion time by efficient provisions of UL grant allocation to send a RRC Re-EstablishmentComplete. Using the disclosed method, there is drastic signaling reduction/resource wastage during the RRE procedure, thereby resulting in power saving of the UE and the network apparatus.
1 . A method performed by a network apparatus for handling a radio resource control (RRC) re-establishment procedure in a wireless network, the method comprising:
receiving, from a user equipment (UE), an RRC re-establishment request in accordance with a radio link failure being detected in the UE;
transmitting, to the UE, a downlink RRC re-establishment message;
receiving, from the UE, a hybrid automatic repeat request (HARQ) level acknowledgement for the transmitted downlink RRC re-establishment message;
transmitting, to the UE, downlink control information (DCI) including a pre-emptive uplink resource grant in response to receiving the HARQ level acknowledgement for the transmitted downlink RRC re-establishment message; and
receiving, from the UE, an RRC re-establishment complete message uplink resources of the pre-emptive uplink resource grant.
2 . The method of claim 1 ,
wherein the
uplink resources for the RRC re-establishment complete message is provided to the UE without a random access procedure between a transmission of the downlink RRC re-establishment message and a reception of the RRC re-establishment complete message.
3 . The method of claim 1 ,
wherein
the HARQ level acknowledgement for the transmitted downlink RRC re-establishment message is received on a common physical uplink control channel (PUCCH),
wherein the RRC re-establishment complete message is received on a physical uplink shared channel (PUSCH), and
wherein the pre-emptive uplink resource grant of the DCI is allocated to the UE in response to the HARQ level acknowledgement autonomously without receiving a resource request to transmit the RRC re-establishment complete message.
4 . A method performed by a user equipment (UE) for handling a radio resource control (RRC) re-establishment procedure in a wireless network, the method comprising:
in response to detecting a radio link failure,
transmitting, to a network apparatus, an RRC re-establishment request message;
receiving, from the network apparatus, a downlink RRC re-establishment message;
transmitting, to the network apparatus, a hybrid automatic repeat request (HARQ) level acknowledgement for the received downlink RRC re-establishment message;
receiving, from the network apparatus, downlink control information (DCI) including a pre-emptive uplink resource grant in accordance with the HARQ level acknowledgement for the downlink RRC re-establishment message; and
transmitting, to the network apparatus, an RRC re-establishment complete message on uplink resources of the pre-emptive uplink resource grant.
5 . The method of claim 4 ,
wherein
the uplink resources for the RRC re-establishment complete message is obtained without a random access procedure between a reception of the downlink RRC re-establishment message and a transmission of the RRC re-establishment complete message.
6 . The method of claim 4 ,
wherein
the HARQ level acknowledgement for the downlink RRC re-establishment message is transmitted on a common physical uplink control channel (PUCCH),
wherein the RRC re-establishment complete message is transmitted on a physical uplink shared channel (PUSCH), and
wherein the pre-emptive uplink resource grant of the DCI is received without transmitting a resource request to transmit the RRC re-establishment complete message.
7 . A network apparatus configured to handle a radio resource control (RRC) re-establishment procedure in a wireless network, the network apparatus comprising:
communication circuitry;
a memory, including storage medium, storing instructions; and
at least one processor including processing circuitry,
wherein the instructions, when executed by the at least one processor, individually and/or collectively, cause the network apparatus to:
receive, from a user equipment (UE), an RRC re-establishment request message in accordance with a radio link failure detected in the UE;
transmit, to the UE, a downlink RRC re-establishment message;
receive, from the UE, a hybrid automatic repeat request (HARQ) level acknowledgement for the transmitted downlink RRC re-establishment message;
transmit, to the UE, downlink control information (DCI) including a pre-emptive uplink resource grant in response to receiving the HARQ level acknowledgement for the transmitted downlink RRC re-establishment message; and
receive, from the UE, a RRC re-establishment complete message on uplink resources of the pre-emptive uplink resource grant.
8 . The network apparatus of claim 7 ,
wherein
the uplink resources for the RRC re-establishment complete message is provided to the UE without a random access procedure between a transmission of the downlink RRC re-establishment message and a reception of the RRC re-establishment complete message.
9 . The network apparatus of claim 7 ,
wherein
the HARQ level acknowledgement for the transmitted downlink RRC re-establishment message is received on a common physical uplink control channel (PUCCH),
wherein the RRC re-establishment complete message is received on a physical uplink shared channel (PUSCH), and
wherein the pre-emptive uplink resource grant of the DCI is allocated to the UE in response to the HARQ level acknowledgement autonomously without receiving a resource request to transmit the RRC re-establishment message.
10 . A user equipment (UE) configured to handle a radio resource control (RRC) re-establishment procedure in a wireless network, the UE comprising:
communication circuitry;
a memory, including storage medium, storing instructions; and
at least one processor including processing circuitry, wherein the instructions, when executed by the at least one processor, individually and/or collectively, cause the UE to:
in response to
detecting a radio link failure,
transmit, to a network apparatus, an RRC re-establishment request message;
receive, from the network apparatus, a downlink RRC re-establishment message;
transmit, to the network apparatus, a hybrid automatic repeat request (HARQ) level acknowledgement for the received downlink RRC re-establishment message;
receive, from the network apparatus, downlink control information (DCI) including a pre-emptive uplink resource grant in accordance with the HARQ level acknowledgement for the downlink RRC re-establishment message; and
transmit, to the network apparatus, a RRC re-establishment complete message on uplink resources of the pre-emptive uplink resource grant.
11 . The UE of claim 10 ,
wherein the uplink resources for the RRC re-establishment complete message is obtained without a random access procedure between a reception of the downlink RRC re-establishment message and a transmission of the RRC re-establishment complete message.
12 . The UE of claim 10 ,
wherein the HARQ level acknowledgement for the downlink RRC re-establishment message is transmitted on a common physical uplink control channel (PUCCH),
wherein the RRC re-establishment complete message is transmitted on a physical uplink shared channel (PUSCH), and
wherein the pre-emptive uplink resource grant of the DCI is received without transmitting resource request to transmit the RRC re-establishment complete message.