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. A method in a user equipment, comprising:
establishing a discontinuous reception (DRX) communication with a network access device;
transmitting a sounding reference signal (SRS) during DRX active time when signaled by the network access device to operate in a first mode;
transmitting an SRS irrespective of the DRX active time when signaled by the network access device to operate in a second mode;
releasing a resource configuration for the user equipment to transmit the SRS upon expiration of a time alignment timer; and
maintaining the resource configuration for the user equipment to transmit the SRS when not in the DRX active time.
2. The method of claim 1 , wherein the DRX active time is associated with DRX operation in a connected mode.
3. The method of claim 1 , further comprising not monitoring a control channel when not in the DRX active time.
4. The method of claim 1 , further comprising determining the resource configuration for the user equipment to transmit the SRS based on a Sounding Reference Signal configuration element received from the network access device.
5. The method of claim 1 , further comprising entering a reduced power state when not in the DRX active time.
6. The method of claim 1 , further comprising receiving an instruction from the network access device for operation in the first mode.
7. The method of claim 1 , wherein when operating with DRX in the first mode, the UE refrains from transmitting the SRS when not during the DRX active time.
8. A user equipment (UE) for a wireless telecommunications system, comprising:
a transmitter, the transmitter configured to transmit a sounding reference signal (SRS); and
a processor, the processor configured to perform operations comprising:
establishing a discontinuous reception (DRX) communication with a network access device;
instructing the transmitter to transmit the SRS during the DRX active time when signaled by the network access device to operate in a first mode;
instructing the transmitter to transmit the SRS irrespective of the DRX active time when signaled by the network access device to operate in a second mode;
releasing a resource configuration for the user equipment to transmit the SRS upon expiration of a time alignment timer; and
maintaining the resource configuration for the user equipment to transmit the SRS when not in the DRX active time.
9. The UE of claim 8 , wherein the DRX active time is associated with DRX operation in a connected mode.
10. The UE of claim 8 , wherein the processor is further configured to not monitor a control channel when not in the DRX active time.
11. The UE of claim 8 , wherein the processor is further configured to determine the resource configuration for the user equipment to transmit the SRS based on a Sounding Reference Signal configuration element received from the network access device.
12. The UE of claim 8 , wherein the processor is further configured to cause the UE to enter a reduced power state when not in the DRX active time.
13. The UE of claim 8 , further comprising a received configured to receive an instruction from the network access device for operation in the first mode.
14. The UE of claim 8 , wherein when operating with DRX in the first operation mode, the UE refrains from transmitting the SRS when not during the DRX active time.