Data packet delivery in RRC inactive state
A method for wireless communication of a user equipment (UE) in a radio resource control (RRC) Inactive state, the method includes sending, by the UE, an RRC Connection Resume Request message to a base station, and transmitting, by the UE, a packet to the base station using one or more radio resources allocated by the base station, where the base station identifies the UE based on the RRC Connection Resume Request message, which includes a UE ID or a UE-specific preamble. Before the UE enters the RRC Inactive state, the base station sends a pre-configured random access configuration to the UE for transmitting the packet in a subsequent a random access procedure. The pre-configured random access configuration includes at least one of a pre-configured bandwidth part configuration, a plurality of access control parameters, the UE ID, and a time pattern for the random access procedure.
1. A method for wireless communication in a wireless communication network having a user equipment (UE), a first base station, a second base station, and a core network (CN), the method comprising:
transitioning to Radio Resource Control (RRC) Inactive state, by the UE, after receiving an RRC state configuration message from the first base station, wherein the first base station provides the RRC state configuration message after receiving RRC Inactive state assistance information comprising input from the UE, the input including the UE's capability information on whether the UE supports RRC Inactive state;
sending, by the UE, an RRC Connection Resume Request message to the second base station;
transmitting, by the UE, at least one packet to the second base station using one or more radio resources allocated by the second base station;
wherein the second base station identifies the UE based on the RRC Connection Resume Request message.
2. The method of claim 1 , wherein information on the one or more radio resources allocated for transmission of the at least one packet is sent by the second base station to the UE in a random access response message.
3. The method of claim 1 , wherein the UE receives a pre-configured random access configuration in the RRC state configuration message, and wherein the UE is configured to apply the pre-configured random access configuration in a random access procedure to transmit the at least one packet to the second base station.
4. The method of claim 3 , wherein, the pre-configured random access configuration comprises at least one of a pre-configured bandwidth part (BWP) configuration, a plurality of access control parameters, a UE ID, and a time pattern of random access.
5. The method of claim 4 , wherein the pre-configured BWP configuration comprises at least one of a numerology, a bandwidth, a frequency location, an uplink waveform.
6. The method of claim 4 , wherein the plurality of access control parameters includes one or more logical channels enabled to transmit the at least one packet.
7. The method of claim 1 , wherein the RRC Connection Resume Request message comprises a UE identifier, which is provided by the first base station in the RRC state configuration message, for the second base station to identify the UE.
8. The method of claim 1 , wherein the at least one packet is transmitted using the one or more radio resources from at least one grant-free resource pool based on a pre-configured BWP configuration.
9. The method of claim 1 , wherein, after the second base station receives the at least one packet, the second base station sends an RRC Suspend message to the UE so that the UE stays in the RRC Inactive state.
10. The method of claim 1 , wherein information on the one or more radio resources allocated for transmission of the at least one packet is sent by the second base station to the UE in a random access response message.
11. The method of claim 1 , wherein, before sending the RRC Connection Resume Request message, the UE sends a random access preamble to the second base station, the random access preamble is associated with random access resources including time and/or frequency radio resources that are reserved for a plurality of UEs for packet transmission.
12. The method of claim 1 , wherein the at least one packet includes an indicator indicating whether another packet is pending for transmission from the UE to the second base station.
13. The method of claim 12 , wherein, when the indicator indicates that the another packet is pending for transmission, the second base station allocates additional uplink grant resources to the UE for transmitting the another packet.
14. The method of claim 1 , wherein after the second base station receives the at least one packet, the second base station sends an RRC Suspend message to the UE so that the UE stays in the RRC Inactive state.
15. The method of claim 1 , wherein the UE transmits the at least one packet without establishing an RRC connection with the second base station.
16. A user equipment (UE) for wireless communication in a wireless communication network, the UE comprising:
one or more non-transitory computer-readable media having computer-executable instructions embodied thereon;
at least one processor coupled to the one or more non-transitory computer-readable media, and configured to execute the computer-executable instructions to:
transition to Radio Resource Control (RRC) Inactive state, by the UE, after receiving an RRC state configuration message from a first base station, wherein the first base station provides the RRC state configuration message after receiving RRC Inactive state assistance information comprising input from the UE, the input including the UE's capability information on whether the UE supports RRC Inactive state;
send an RRC Connection Resume Request message to a second base station;
transmit at least one packet to the second base station using one or more radio resources allocated by the second base station;
wherein the second base station identifies the UE based on the RRC Connection Resume Request message.
17. The UE of claim 16 , wherein the UE receives a pre-configured random access configuration in the RRC state configuration message, and wherein the UE is configured to apply the pre-configured random access configuration in a random access procedure to transmit the at least one packet.
18. The UE of claim 17 , wherein, the pre-configured random access configuration comprises at least one of a pre-configured bandwidth part (BWP) configuration, a plurality of access control parameters, a UE ID, and a time pattern of random access.
19. The UE of claim 18 , wherein the pre-configured BWP configuration comprises at least one of a numerology, a bandwidth, a frequency location, and an uplink waveform.
20. The UE of claim 18 , wherein the plurality of access control parameters includes one or more logical channels enabled to transmit the at least one packet.
21. The UE of claim 16 , wherein the RRC Connection Resume Request message comprises a UE identifier, which is provided by the first base station in the RRC state configuration message, for the second base station to identify the UE.
22. The UE of claim 16 , wherein the at least one packet is transmitted using the one or more radio resources from at least one grant-free resource pool based on a default BWP configuration or a pre-configured BWP configuration.
23. The UE of claim 16 , wherein the at least one packet includes an indicator indicating whether another packet is pending for transmission from the UE to the second base station.
24. The UE of claim 16 , wherein after the second base station receives the at least one packet, the second base station sends an RRC Suspend message to the UE so that the UE stays in the RRC Inactive state.
25. The UE of claim 16 , wherein the UE transmits the at least one packet without establishing an RRC connection with the second base station.