Methods and apparatus for timing synchronization during a wireless uplink random access procedure

1. A method of wireless communication by a user equipment (UE), comprising:

receiving first timing advance information associated with uplink wireless communications with a base station (BS);

initiating a first timer associated with the first timing advance information to measure a valid time period for the first timing advance information;

transmitting a random access connection request message to the BS;

receiving a random access response from the BS while the first timing advance information is within the valid time period for the first timing advance information, the random access response comprising second timing advance information associated with uplink wireless communications with the BS;

transmitting a radio resource control (RRC) connection request to the BS after receiving the random access response;

receiving a contention resolution response from the BS responsive to the RRC connection request;

determining, after receiving the contention resolution response, that the valid time period for the first timing advance information has expired;

utilizing the second timing advance information for uplink communications with the BS after determining that the valid time period for the first timing advance information has expired;

initiating a second timer, different from the first timer, associated with the second timing advance information for a valid time period for the second timing advance information after determining that the valid time period for the first timing advance information has expired; and

adjusting an expiration of the second timer based on an elapsed time between the receipt of the random access response and the expiration of the valid time period for the first timing advance information.

2. The method of claim 1 , further comprising transmitting uplink data to the BS, wherein the transmitting uplink data utilizes:

the first timing advance information when the first timing advance information is within the valid time period for the first timing advance information; and

the second timing advance information when the valid time period for the first timing advance information has expired.

3. The method of claim 1 , wherein utilizing the second timing advance information for uplink communications with the BS after determining that the valid time period for the first timing advance information has expired comprises

transmitting a scheduling request to the BS utilizing the second timing advance information.

4. The method of claim 1 , further comprising storing the second timing advance information received in the random access response.

5. The method of claim 4 , wherein the storing of the second timing advance information is performed after it is determined that the first timing advance information is within the valid time period for the first timing advance information.

6. The method of claim 1 , wherein the RRC connection request is transmitted to the BS using a unique UE identification; and wherein the contention resolution response received from the BS responsive to the RRC connection request comprises the unique UE identification.

7. The method of claim 1 , wherein the BS is an enhanced-NodeB (eNodeB) within a Long Term Evolution (LTE) wireless communications network.

8. An apparatus for wireless communications, comprising:

at least one processor configured to:

receive first timing advance information associated with uplink wireless communications with a base station (BS);

initiate a first timer associated with the first timing advance information to measure a valid time period for the first timing advance information;

transmit a random access connection request message to the BS;

receive a random access response from the BS while the first timing advance information is within the valid time period for the first timing advance information, the random access response comprising second timing advance information associated with uplink wireless communications with the BS;

transmit a radio resource control (RRC) connection request to the BS after receiving the random access response;

receive a contention resolution response from the BS responsive to the RRC connection request;

determine, after receiving the contention resolution response, that the valid time period for the first timing advance information has expired;

utilize the second timing advance information for uplink communications with the BS after determining that the valid time period for the first timing advance information has expired;

initiate a second timer, different from the first timer, associated with the second timing advance information for a valid time period for the second timing advance information after determining that the valid time period for the first timing advance information has expired; and

adjust an expiration of the second timer based on an elapsed time between the receipt of the random access response and the expiration of the valid time period for the first timing advance information; and

a memory coupled to the at least one processor.

9. The apparatus of claim 8 , wherein the at least one processor is further configured to:

transmit uplink data utilizing the first timing advance information when the first timing advance information is within the valid time period for the first timing advance information; and

transmit uplink data utilizing the second timing advance information when the valid time period for the first timing advance information has expired.

10. The apparatus of claim 8 , wherein the at least one processor is configured to utilize the second timing advance information for uplink communications with the BS after determining that the valid time period for the first timing advance information has expired by

transmitting a scheduling request to the BS utilizing the second timing advance information.

11. The apparatus of claim 8 , the at least one processor is further configured to store the second timing advance information received in the random access response.

12. The apparatus of claim 11 , wherein the at least one processor is further configured to store the second timing advance information after it is determined that the first timing advance information is within the valid time period for the first timing advance information.

13. The apparatus of claim 8 , wherein the RRC connection request is transmitted to the BS using a unique UE identification; and wherein the contention resolution response received from the BS responsive to the RRC connection request comprises the unique UE identification.

14. The apparatus of claim 8 , wherein the BS is an enhanced-NodeB (eNodeB) within a Long Term Evolution (LTE) wireless communications network.

15. An apparatus for wireless communications, comprising:

means for receiving first timing advance information associated with uplink wireless communications with a base station (BS);

means for initiating a first timer associated with the first timing advance information to measure a valid time period for the first timing advance information;

means for transmitting a random access connection request message to the BS;

means for receiving a random access response from the BS while the first timing advance information is within the valid time period for the first timing advance information, the random access response comprising second timing advance information associated with uplink wireless communications with the BS;

means for transmitting a radio resource control (RRC) connection request to the BS after receiving the random access response;

means for receiving a contention resolution response from the BS responsive to the RRC connection request;

means for determining, after receiving the contention resolution response, that the valid time period for the first timing advance information has expired;

means for utilizing the second timing advance information for uplink communications with the BS after determining that the valid time period for the first timing advance information has expired;

means for initiating a second timer, different from the first timer, associated with the second timing advance information for a valid time period for the second timing advance information after determining that the valid time period for the first timing advance information has expired; and

means for adjusting an expiration of the second timer based on an elapsed time between the receipt of the random access response and the expiration of the valid time period for the first timing advance information.

16. The apparatus of claim 15 , further comprising:

means for transmitting uplink data to the BS,

wherein the means for transmitting uplink data utilizes the first timing advance information when the first timing advance information is within the valid time period for the first timing advance information, and wherein the means for transmitting uplink data utilizes the second timing advance information when the valid time period for the first timing advance information has expired.

17. The apparatus of claim 15 , wherein

the means for utilizing the second timing advance information for uplink communications with the BS after determining that the valid time period for the first timing advance information has expired comprises means for transmitting a scheduling request to the BS utilizing the second timing advance information.

18. The apparatus of claim 15 , further comprising means for storing the second timing advance information received in the random access response.

19. The apparatus of claim 18 , wherein the storing of the second timing advance information is performed after it is determined that the first timing advance information is within the valid time period for the first timing advance information.

20. The apparatus of claim 15 , wherein

the RRC connection request is transmitted to the BS using a unique user equipment (UE) identification; and wherein the

contention resolution response received from the BS responsive to the RRC connection request comprises the unique UE identification.

21. The apparatus of claim 15 , wherein the BS is an enhanced-NodeB (eNodeB) within a Long Term Evolution (LTE) wireless communications network.

22. A non-transitory computer-readable medium encoded with one or more instructions, the one or more instructions executable by one or more processors for:

receiving first timing advance information associated with uplink wireless communications with a base station (BS);

initiating a first timer associated with the first timing advance information to measure a valid time period for the first timing advance information;

transmitting a random access connection request message to the BS;

receiving a random access response from the BS while the first timing advance information is within the valid time period for the first timing advance information, the random access response comprising second timing advance information associated with uplink wireless communications with the BS;

transmitting a radio resource control (RRC) connection request to the BS after receiving the random access response;

receiving a contention resolution response from the BS responsive to the RRC connection request;

determining, after receiving the contention resolution response, that the valid time period for the first timing advance information has expired;

utilizing the second timing advance information for uplink communications with the BS after determining that the valid time period for the first timing advance information has expired;

initiating a second timer, different from the first timer, associated with the second timing advance information for a valid time period for the second timing advance information after determining that the valid time period for the first timing advance information has expired; and

adjusting an expiration of the second timer based on an elapsed time between the receipt of the random access response and the expiration of the valid time period for the first timing advance information.

23. The non-transitory computer-readable medium of claim 22 , wherein the computer-readable medium further comprises one or more instructions for transmitting uplink data to the BS,

wherein the one or more instructions for transmitting uplink data utilizes the first timing advance information when the first timing advance information is within the valid time period for the first timing advance information, and wherein the one or more instructions for transmitting uplink data utilizes the second timing advance information when the valid time period for the first timing advance information has expired.

24. The non-transitory computer-readable medium of claim 22 , wherein the one or more instructions for utilizing the second timing advance information for uplink communications with the BS after determining that the valid time period for the first timing advance information has expired comprises one or more instructions for

transmitting a scheduling request to the BS utilizing the second timing advance information.

25. The non-transitory computer-readable medium of claim 22 , wherein the computer-readable medium further comprises one or more instructions for storing the second timing advance information received in the random access response.

26. The non-transitory computer-readable medium of claim 25 , wherein the storing of the second timing advance information is performed after it is determined that the first timing advance information is within the valid time period for the first timing advance information.

27. The non-transitory computer-readable medium of claim 22 , wherein the RRC connection request is transmitted to the BS using a unique UE identification; and wherein the

contention resolution response received from the BS responsive to the RRC connection request comprises the unique UE identification.

28. The non-transitory computer-readable medium of claim 22 , wherein the BS is an enhanced-NodeB (eNodeB) within a Long Term Evolution (LTE) wireless communications network.

29. A user equipment (UE), comprising:

a receiver configured to receive first timing advance information associated with uplink wireless communications with a base station (BS);

a transmitter configured to:

transmit a random access connection request message to the BS, wherein the receiver is further configured to receive a random access response from the BS while the first timing advance information associated with uplink wireless communications with the BS is within a valid time period for the first timing advance information, the random access response comprising second timing advance information associated with uplink wireless communications with the BS; and

transmit a radio resource control (RRC) connection request to the BS after the receiver receives the random access response, wherein the receiver is further configured to receive a contention resolution response from the BS responsive to the RRC connection request; and

at least one processor configured to:

initiate a first timer associated with the first timing advance information to measure the valid time period for the first timing advance information;

determine, after the receiver receives the contention resolution response, that the valid time period for the first timing advance information has expired;

utilize the second timing advance information for uplink communications with the BS after determining that the valid time period for the first timing advance information has expired;

initiate a second timer, different from the first timer, associated with the second timing advance information for a valid time period for the second timing advance information after determining that the valid time period for the first timing advance information has expired; and

adjust an expiration of the second timer based on an elapsed time between the receipt of the random access response and the expiration of the valid time period for the first timing advance information.