Timing adjustment for synchronous operation in a wireless network

1. A method for wireless communication, comprising:

identifying a first user equipment (UE) located within a coverage of a first base station;

advancing a transmit timing of the first UE relative to a transmit timing of the first base station by an amount larger than twice a propagation delay between the first UE and the first base station; and

delaying the transmit timing of the first base station relative to a transmit timing of a second base station in communication with a second UE within the coverage of the first base station.

2. The method of claim 1 , wherein advancing the transmit timing of the first UE comprises advancing the transmit timing of the first UE to time align uplink signals from the first UE and the second UE at the first base station.

3. The method of claim 2 , wherein the first base station is a femto base station and the second base station is a macro base station, and wherein the first UE communicates with the femto base station.

4. The method of claim 2 , wherein advancing the transmit timing of the first UE comprises:

determining a second propagation delay between the second base station and one of the first UE, the second UE, or the first base station, and

determining an amount of advance for the transmit timing of the first UE based on the second propagation delay.

5. The method of claim 2 , wherein advancing the transmit timing of the first UE comprises:

receiving an uplink transmission from the second UE at the first base station, and

determining the transmit timing of the first UE based on a receive time of the uplink transmission from the second UE at the first base station.

6. The method of claim 2 , wherein advancing the transmit timing of the first UE comprises:

determining a timing adjustment for the first UE to time align the uplink signals from the first UE and the second UE at the first base station, and

sending the timing adjustment to the first UE.

7. The method of claim 6 , wherein the identifying the first UE comprises receiving a random access probe from the first UE at the first base station, and wherein the timing adjustment is determined and sent to the first UE in response to the random access probe.

8. The method of claim 1 , wherein the transmit timing of the first base station is delayed by a particular amount and the transmit timing of the first UE is advanced by the particular amount relative to the transmit timing of the second base station.

9. The method of claim 1 , further comprising:

determining a guard interval of at least a difference between the transmit timing of the first base station and the transmit timing of the first UE; and

using the guard interval for an uplink transmission from the first UE following a downlink transmission from the first base station.

10. The method of claim 9 , wherein the guard interval is set to a value determined based on a cell size of a second base station.

11. An apparatus for wireless communication, comprising:

means for identifying a first user equipment (UE) located within a coverage of a first base station;

means for advancing a transmit timing of the first UE relative to a transmit timing of the first base station by an amount larger than twice a propagation delay between the first UE and the first base station; and

means for delaying the transmit timing of the first base station relative to a transmit timing of a second base station in communication with a second UE within the coverage of the first base station.

12. The apparatus of claim 11 , wherein the means for advancing the transmit timing of the first UE comprises means for advancing the transmit timing of the first UE to time align uplink signals from the first UE and the second UE at the first base station.

13. The apparatus of claim 12 , wherein the means for advancing the transmit timing of the first UE comprises

means for determining a second propagation delay between the second base station and one of the first UE, or the second UE, or the first base station, and

means for determining an amount of advance for the transmit timing of the first UE based on the second propagation delay.

14. The apparatus of claim 1 , wherein the means for advancing the transmit timing of the first UE comprises

means for receiving an uplink transmission from the second UE at the first base station, and

means for determining the transmit timing of the first UE based on a receive time of the uplink transmission from the second UE at the first base station.

15. The apparatus of claim 12 , wherein the means for advancing the transmit timing of the first UE comprises

means for determining a timing adjustment for the first UE to time align the uplink signals from the first UE and the second UE at the first base station, and

means for sending the timing adjustment to the first UE.

16. The apparatus of claim 11 , further comprising:

means for determining a guard interval of at least a difference between the transmit timing of the first base station and the transmit timing of the first UE; and

means for using the guard interval for an uplink transmission from the first UE following a downlink transmission from the first base station.

17. An apparatus for wireless communication, comprising:

at least one processor configured to identify a user equipment (UE) located within a coverage of a base station, to advance a transmit timing of the UE relative to a transmit timing of the base station by an amount larger than twice a propagation delay between the UE and the base station, and to delay the transmit timing of the first base station relative to a transmit timing of a second base station in communication with a second UE within the coverage of the first base station.

18. A non-transitory computer readable medium storing code for wireless communication, the code comprising instructions executable by a processor to:

identify a user equipment (UE) located within a coverage of a base station,

advance a transmit timing of the UE relative to a transmit timing of the base station by an amount larger than twice a propagation delay between the UE and the base station; and

delay the transmit timing of the first base station relative to a transmit timing of a second base station in communication with a second UE within the coverage of the first base station.

19. A method for wireless communication, comprising:

sending a random access probe from a first user equipment (UE);

receiving, in response to the random access probe, a timing adjustment to advance a transmit timing of the first UE relative to a transmit timing of a first base station by an amount larger than twice a propagation delay between the first UE and the first base station; and

sending an uplink transmission from the first UE to the first base station based on the transmit timing of the first UE.

20. The method of claim 19 , wherein the transmit timing of the first UE is advanced to time align uplink signals from the first UE and a second UE at the first base station, the first UE being located within coverage of the first base station and a second base station, and the second UE communicating with the second base station.

21. The method of claim 20 , further comprising:

performing ranging between the first UE and the second base station to determine a second propagation delay between the second base station and the first UE, wherein the transmit timing of the first UE is advanced by an amount determined based on the second propagation delay.

22. An apparatus for wireless communication, comprising:

means for sending a random access probe from a first user equipment (UE);

means for receiving, in response to the random access probe, a timing adjustment to advance a transmit timing of the first UE relative to a transmit timing of a first base station by an amount larger than twice a propagation delay between the first UE and the first base station; and

means for sending an uplink transmission from the first UE to the first base station based on the transmit timing of the first UE.

23. The apparatus of claim 22 , wherein the transmit timing of the first UE is advanced to time align uplink signals from the first UE and a second UE at the first base station, the first UE being located within coverage of the first base station and a second base station, and the second UE communicating with the second base station.

24. The apparatus of claim 23 , further comprising:

means for performing ranging between the first UE and the second base station to determine a second propagation delay between the second base station and the first UE, wherein the transmit timing of the first UE is advanced by an amount determined based on the second propagation delay.

25. An apparatus for wireless communication, comprising:

at least one processor configured to send a random access probe from a first user equipment (UE), to receive, in response to the random access probe, a timing adjustment to advance a transmit timing of the first UE relative to a transmit timing of a first base station by an amount larger than twice a propagation delay between the first UE and the first base station, and to send an uplink transmission from the first UE to the first base station based on the transmit timing of the first UE.

26. A non-transitory computer readable medium storing code for wireless communication, the code comprising instructions executable by a processor to:

send a random access probe from a first user equipment (UE);

receive a timing adjustment to advance a transmit timing of the first UE relative to a transmit timing of a first base station by an amount larger than twice a propagation delay between the first UE and the first base station, and

send an uplink transmission from the first UE to the first base station based on the transmit timing of the first UE.