Method and apparatus for transmission in inactive state in a wireless communication system

1. A method of a User Equipment (UE), the method comprising:

receiving, via a Radio Resource Control (RRC) message, a resource configuration of a first configured grant to be used in RRC inactive state;

performing a first new transmission using the first configured grant in RRC inactive state;

receiving, after the performing the first new transmission using the first configured grant, an uplink grant, associated with a Hybrid Automatic Repeat Request (HARQ) process, in RRC inactive state via Physical Downlink Control Channel (PDCCH); and

performing a second new transmission using the uplink grant in RRC inactive state if the uplink grant is addressed to a first Radio Network Temporary Identifier (RNTI) and a new data indicator (NDI) for the HARQ process associated with the uplink grant addressed to the first RNTI is toggled, or performing a first retransmission using the uplink grant in RRC inactive state if the uplink grant is addressed to a second RNTI and the NDI for the HARQ process associated with the uplink grant addressed to the second RNTI is not toggled.

2. The method of claim 1 , wherein:

the HARQ process is configured for performing the first new transmission.

3. The method of claim 1 , wherein:

determining whether the uplink grant is for performance of the second new transmission or for performance of the first retransmission comprises determining that the uplink grant is for performance of the second new transmission if the NDI is considered to be toggled; and

the determining whether the uplink grant is for performance of the second new transmission or for performance of the first retransmission comprises determining that the uplink grant is for performance of the first retransmission if the NDI is considered to be not toggled.

4. The method of claim 1 , wherein the first RNTI is Cell RNTI (C-RNTI) and the second RNTI is Configured Scheduling RNTI (CS-RNTI).

5. The method of claim 1 , wherein:

the uplink grant is for performance of a new dynamic scheduled transmission or a retransmission of a dynamic scheduled transmission if the uplink grant is addressed to the first RNTI; and

the uplink grant is for performance of a retransmission of a configured transmission if the uplink grant is addressed to the second RNTI.

6. The method of claim 5 , wherein:

the new dynamic scheduled transmission corresponds to a new transmission using a dynamic grant; and

the configured transmission corresponds to a new transmission using a configured grant.

7. The method of claim 1 , wherein:

the first new transmission corresponds to a new transmission of a first Medium Access Control Protocol Data Unit (MAC PDU);

the second new transmission corresponds to a new transmission of a second MAC PDU; and

the first retransmission corresponds to a retransmission of the first MAC PDU.

8. The method of claim 1 , wherein

the first RNTI is used in RRC connected mode and is reused in RRC inactive state and the second RNTI is configured in RRC connected mode and is to be used in RRC inactive state.

9. A User Equipment (UE) comprising:

a control circuit;

a processor installed in the control circuit; and

a memory installed in the control circuit and operatively coupled to the processor, wherein the processor is configured to execute a program code stored in the memory to perform operations, the operations comprising:

receiving, via a Radio Resource Control (RRC) message, a resource configuration of a first configured grant to be used in RRC inactive state;

performing a first new transmission using the first configured grant in RRC inactive state;

receiving, after the performing the first new transmission using the first configured grant, an uplink grant, associated with a Hybrid Automatic Repeat Request (HARQ) process, in RRC inactive state via Physical Downlink Control Channel (PDCCH);

and

performing a second new transmission using the uplink grant in RRC inactive state the uplink grant is addressed to a first Radio Network Temporary Identifier (RNTI) and a new data indicator (NDI) for the HARQ process associated with the uplink grant addressed to the first RNTI is toggled, or performing a first retransmission using the uplink grant in RRC inactive state if the uplink grant is addressed to a second RNTI and the NDI for the HARQ process associated with the uplink grant addressed to the second RNTI is not toggled.

10. The UE of claim 9 , wherein:

the HARQ process is configured for performing the first new transmission.

11. The UE of claim 9 , wherein:

the determining whether the uplink grant is for performance of the second new transmission or for performance of the first retransmission is based on whether the NDI is considered to be toggled or not toggled; and

the determination that the uplink grant is for performance of the second new transmission is based on a determination that the NDI is considered to be toggled.

12. The UE of claim 9 , wherein:

determining whether the uplink grant is for performance of the second new transmission or for performance of the first retransmission is based on whether the uplink grant is addressed to the first RNTI indicative of the uplink grant being for performance of the second new transmission or the second RNTI indicative of the uplink grant being for performance of the first retransmission; and

the determination that the uplink grant is for performance of the second new transmission is based on a determination that the uplink grant is addressed to the first RNTI.

13. The UE of claim 9 , wherein the first RNTI is Cell RNTI (C-RNTI) and the second RNTI is Configured Scheduling RNTI (CS-RNTI).

14. The UE of claim 9 , wherein:

the first new transmission corresponds to a new transmission of a first Medium Access Control Protocol Data Unit (MAC PDU);

the second new transmission corresponds to a new transmission of a second MAC PDU; and

the first retransmission corresponds to a retransmission of the first MAC PDU.

15. The UE of claim 9 , wherein

the first RNTI is used in RRC connected mode and is reused in RRC inactive state and the second RNTI is configured in RRC connected mode and is to be used in RRC inactive state.

16. A method of a User Equipment (UE), the method comprising:

receiving, via a Radio Resource Control (RRC) message, a resource configuration of a first configured grant to be used in RRC inactive state;

performing a first new transmission using the first configured grant in RRC inactive state;

receiving, after the performing the first new transmission using the first configured grant, an uplink grant, associated with a Hybrid Automatic Repeat Request (HARQ) process, in RRC inactive state via Physical Downlink Control Channel (PDCCH);

determining a Radio Network Temporary Identifier (RNTI) to which the uplink grant is addressed, wherein the RNTI is a Cell RNTI (C-RNTI) or a Configured Scheduling RNTI (CS-RNTI), wherein the C RNTI was used in RRC connected mode and is reused in RRC inactive state and the CS-RNTI was configured in RRC connected mode and is used in RRC inactive state;

determining, based on the RNTI to which the uplink grant is addressed, whether the uplink grant received after the performing the first new transmission using the first configured grant is for performance of a second new transmission or for performance of a first retransmission; and

performing the second new transmission using the uplink grant in RRC inactive state if the UE determines that the uplink grant is for performance of the second new transmission.

17. The method of claim 16 , wherein:

the determining whether the uplink grant is for performance of the second new transmission or for performance of the first retransmission is based on a new data indicator (NDI) in the uplink grant.

18. The method of claim 17 , wherein:

the determining whether the uplink grant is for performance of the second new transmission or for performance of the first retransmission comprises determining that the uplink grant is for performance of the second new transmission if the NDI is considered to be toggled; and

the determining whether the uplink grant is for performance of the second new transmission or for performance of the first retransmission comprises determining that the uplink grant is for performance of the first retransmission if the NDI is considered to be not toggled.

19. The method of claim 16 , wherein:

the determining whether the uplink grant is for performance of the second new transmission or for performance of the first retransmission comprises determining that the uplink grant is for performance of the second new transmission if the RNTI is the C-RNTI; and

the determining whether the uplink grant is for performance of the second new transmission or for performance of the first retransmission comprises determining that the uplink grant is for performance of the first retransmission if the RNTI is the CS-RNTI.

20. The method of claim 16 , wherein:

the RNTI indicates that the uplink grant is for performance of a new dynamic scheduled transmission or a retransmission of a dynamic scheduled transmission if the RNTI is the C-RNTI; and

the RNTI indicates that the uplink grant is for performance of a retransmission of a configured transmission if the RNTI is the CS-RNTI.

21. The method of claim 16 , wherein the HARQ process is configured for performing the first new transmission.