System and method for uplink timing synchronization in conjunction with discontinuous reception
A system and method are disclosed for providing uplink timing synchronization during DRX operation in a wireless communication system.
1. User equipment for transmitting a channel quality indicator (CQI), the user equipment comprising:
memory storing instructions; and
a processor configured to execute the instructions to cause the user equipment to:
establish a discontinuous reception (DRX) communication with network apparatus;
transmit the CQI during a first DRX active time;
transmit a sounding reference signal (SRS) during a second DRX active time; and
release uplink communication resources for the user equipment to transmit the CQI and the SRS when uplink timing alignment of the user equipment is lost.
2. The user equipment of claim 1 , wherein the first DRX active time and the second DRX active time are the same.
3. The user equipment of claim 1 , wherein the processor is configured to execute the instructions to cause the user equipment to transmit the CQI fewer frequently than transmission of the SRS.
4. The user equipment of claim 3 , wherein the processor is configured to execute the instructions to cause the user equipment to transmit the CQI at half of frequency of the transmission of the SRS.
5. The user equipment of claim 1 , wherein the processor is further configured to execute the instructions to cause the user equipment to transmit the SRS irrespective of DRX active times.
6. The user equipment of claim 1 , wherein the processor is configured to execute the instructions to cause the user equipment to transmit the CQI when a transmitter of the user equipment is turned on.
7. The user equipment of claim 1 , wherein the first and second DRX active times are associated with DRX operations in a connected mode.
8. The user equipment of claim 1 , wherein the processor is further configured to execute the instructions to cause the user equipment to enter a reduced power state when the user equipment is not in DRX active times.
9. The user equipment of claim 1 , wherein the processor is configured to execute the instructions to cause the user equipment not to monitor a control channel when the user equipment is not in DRX active times.
10. A method for transmitting a channel quality indicator (CQI) by user equipment, the method comprising:
establishing a discontinuous reception (DRX) communication with network apparatus;
transmitting the CQI during a first DRX active time;
transmitting a sounding reference signal (SRS) during a second DRX active time; and
releasing uplink communication resources for the user equipment to transmit the CQI and the SRS when uplink timing alignment of the user equipment is lost.
11. The method of claim 10 , wherein the first DRX active time and the second DRX active time are the same.
12. The method of claim 10 , wherein frequency of transmitting the CQI is fewer than frequency of transmitting the SRS.
13. The method of claim 12 , wherein the frequency of transmitting the CQI is half of the frequency of transmitting the SRS.
14. The method of claim 10 , wherein transmitting the SRS includes transmitting the SRS irrespective of DRX active times.
15. The method of claim 10 , wherein transmitting the CQI includes transmitting the CQI when a transmitter of the user equipment is turned on.
16. The method of claim 10 , wherein the first and second DRX active times are associated with DRX operations in a connected mode.
17. The method of claim 10 , further comprising entering a reduced power state when the user equipment is not in DRX active times.
18. The method of claim 10 , further comprising not monitoring a control channel when the user equipment is not in DRX active times.