BASE STATION SYNCHRONIZATION

• US 20100046494A1
• Filed: 08/10/2009
• Published: 02/25/2010
• Est. Priority Date: 08/22/2008
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Xiao, Lei, Agashe, Parag A., Palanki, Ravi
• Granted Patent: US 8,774,084 B2
• Time in Patent Office: Days
• US Class Current: 370/344
• CPC Class Codes: H04W 56/00 Synchronisation arrangements
• CPC Class Codes: H04W 56/0015 one node acting as a reference for the others

Abstract

Systems and methodologies are described that facilitate synchronizing base stations in a wireless communication environment. A base station can receive a synchronization signal sent via a low reuse channel, which can be shared by a group of base stations. Further, the base station can align a clock associated therewith to the received synchronization signal. Moreover, the base station can coarsely align the clock to a first synchronization signal received upon a first subset of resources of the low reuse channel, and finely align the clock to a second synchronization signal received upon a second subset of resources (e.g., of the low reuse channel, of a separate channel, . . . ), where the second subset of resources can be reserved for transmission from at least one base station with at least a predetermined level of synchronous accuracy.

Claims

1. A method, comprising:

receiving a signal at a base station via a low reuse channel; and

aligning a clock of the base station to the signal.

2. The method of claim 1, further comprising:

coarsely aligning the clock of the base station to a first signal received upon a first subset of resources of the low reuse channel; and

finely aligning the clock of the base station to a second signal received upon a second subset of resources, wherein the second subset of resources is reserved for transmission from at least one base station with at least a predetermined level of synchronous accuracy.

3. The method of claim 1, wherein a group of base stations share the low reuse channel, and a first subset of base stations from the group transmit respective signals utilizing resources identified for a coordinated silence upon the low reuse channel and a second subset of base stations from the group forgo transmission of respective signals employing the resources identified for the coordinated silence upon the low reuse channel.

4. The method of claim 1, further comprising receiving the signal from a given transmitting base station in a particular slot from a set of N slots included in the low reuse channel, where N is an integer.

5. The method of claim 4, wherein the particular slot from the set of N slots included in the low reuse channel utilized by the given transmitting base station varies over time.

6. The method of claim 1, wherein the low reuse channel comprises one of a set of subcarriers in an orthogonal frequency division multiple access (OFDMA) system or a frequency band in a frequency division multiple access (FDMA) system.

7. The method of claim 1, further comprising selecting the signal from a set of signals received via the low reuse channel.

8. The method of claim 1, wherein the signal is a synchronization signal.

9. A wireless communications apparatus, comprising:

at least one processor configured to;

receive a synchronization signal at a base station via a low reuse channel; and

tune a clock of the base station to the synchronization signal.

10. The wireless communications apparatus of claim 9, further comprising:

at least one processor configured to;

coarsely tune the clock of the base station to a first synchronization signal received upon a first subset of resources of the low reuse channel; and

finely tune the clock of the base station to a second synchronization signal received upon a second subset of resources of one or more of the low reuse channel or a separate channel, wherein the second subset of resources is reserved for transmission from at least one base station with at least a predetermined level of synchronous accuracy.

11. The wireless communications apparatus of claim 9, wherein a group of base stations share the low reuse channel, and a first subset of base stations from the group transmit respective synchronization signals utilizing resources reserved for a coordinated silence upon the low reuse channel and a second subset of base stations from the group halt transmission of respective synchronization signals employing the resources reserved for the coordinated silence upon the low reuse channel.

12. The wireless communications apparatus of claim 9, further comprising:

at least one processor configured to;

receive the synchronization signal from a particular transmitting base station in a particular time varying slot from a set of N slots included in the low reuse channel, where N is an integer.

13. The wireless communications apparatus of claim 9, wherein the low reuse channel comprises one of a set of subcarriers in an orthogonal frequency division multiple access (OFDMA) system or a frequency band in a frequency division multiple access (FDMA) system.

14. The wireless communications apparatus of claim 9, further comprising:

at least one processor configured to;

choose the synchronization signal from a set of synchronization signals respectively received from a plurality of transmitting base stations via the low reuse channel.

15. An apparatus, comprising:

means for obtaining a set of synchronization signals at a base station via a low reuse channel; and

means for aligning a clock of the base station to at least one synchronization signal from the set.

16. The apparatus of claim 15, further comprising means for selecting the at least one synchronization signal from the set.

17. The apparatus of claim 15, further comprising means for adjusting the clock of the base station as a function of a first synchronization signal obtained over a first subset of resources of the low reuse channel and a second synchronization signal obtained over a second subset of resources of at least one of the low reuse channel or a separate channel.

18. The apparatus of claim 15, wherein a group of base stations share the low reuse channel, and a first subset of base stations from the group transmit respective synchronization signals utilizing resources reserved for a coordinated silence upon the low reuse channel and a second subset of base stations from the group inhibit transmission of respective synchronization signals employing the resources reserved for the coordinated silence upon the low reuse channel.

19. The apparatus of claim 15, wherein a corresponding transmission slot during which each of the synchronization signals in the set is respectively transmitted from a corresponding transmitting base station varies as a function of time.

20. A computer program product, comprising:

a computer-readable medium comprising;

code for causing at least one computer to receive a signal at a base station via a low reuse channel; and

code for causing at least one computer to align a clock of the base station to the signal.

21. The computer program product of claim 20, wherein the computer-readable medium further comprises:

code for causing at least one computer to coarsely align the clock of the base station to a first signal received upon a first subset of resources of the low reuse channel; and

code for causing at least one computer to finely align the clock of the base station to a second signal received upon a second subset of resources, wherein the second subset of resources is reserved for transmission from at least one base station with at least a predetermined level of synchronous accuracy.

22. The computer program product of claim 20, wherein a group of base stations share the low reuse channel, and a first subset of base stations from the group transmit respective signals utilizing resources identified for a coordinated silence upon the low reuse channel and a second subset of base stations from the group forgo transmission of respective signals employing the resources identified for the coordinated silence upon the low reuse channel.

23. The computer program product of claim 20, wherein the computer-readable medium further comprises code for causing at least one computer to receive the signal from a given transmitting base station in a particular slot from a set of N slots included in the low reuse channel, where N is an integer.

24. The computer program product of claim 23, wherein the particular slot from the set of N slots included in the low reuse channel utilized by the given transmitting base station varies over time.

25. The computer program product of claim 20, wherein the low reuse channel comprises one of a set of subcarriers in an orthogonal frequency division multiple access (OFDMA) system or a frequency band in a frequency division multiple access (FDMA) system.

26. The computer program product of claim 20, wherein the computer-readable medium further comprises code for causing at least one computer to choose the signal from a set of signals received via the low reuse channel.

27. An apparatus, comprising:

a reception component that obtains a synchronization signal at a receiving base station via a low reuse channel; and

an adjustment component that aligns a clock of the receiving base station to the obtained synchronization signal.

28. The apparatus of claim 27, further comprising a source selection component that selects the synchronization signal utilized by the adjustment component from a set of synchronization signals received via the low reuse channel.

29. A method, comprising:

generating a synchronization signal based on a clock of a base station; and

transmitting the synchronization signal from the base station over a low reuse channel shared by a group of base stations.

30. The method of claim 29, further comprising transmitting the synchronization signal over the low reuse channel utilizing resources associated with coarse timing.

31. The method of claim 29, wherein the synchronization signal is transmitted over resources that correspond to one or more of time, period, frequency band, or spreading code employed for transmitting the synchronization signal.

32. The method of claim 29, further comprising transmitting the synchronization signal over at least one of the low reuse channel or a separate channel employing resources associated with fine timing when the clock of the base station provides at least a predetermined level of synchronous accuracy.

33. The method of claim 32, further comprising inhibiting transmission of the synchronization signal using the resources associated with fine timing when the clock of the base station lacks at least the predetermined level of synchronous accuracy.

34. The method of claim 33, further comprising:

receiving a disparate synchronization signal via the resources associated with fine timing; and

aligning the clock of the base station to the disparate synchronization signal.

35. The method of claim 29, wherein a first subset of base stations from the group transmit respective synchronization signals utilizing resources identified for a coordinated silence upon the low reuse channel and a second subset of base stations from the group forgo transmission of respective synchronization signals employing the resources identified for the coordinated silence upon the low reuse channel.

36. The method of claim 29, wherein the low reuse channel comprises one of a set of subcarriers in an orthogonal frequency division multiple access (OFDMA) system or a frequency band in a frequency division multiple access (FDMA) system.

37. The method of claim 29, further comprising transmitting the synchronization signal in a particular transmission slot from a set of N transmission slots included in the low reuse channel, where N can be an integer.

38. The method of claim 37, further comprising varying the particular transmission slot from the set of N transmission slots utilized to transmit the synchronization signal over time as a function of a pseudorandom sequence associated with the base station.

39. The method of claim 29, further comprising indicating whether the clock of the base station is one of Global Positioning System (GPS) aligned, self aligned, or aligned from at least one differing base station.

40. A wireless communications apparatus, comprising:

at least one processor configured to;

yield a synchronization signal based on a clock of a base station; and

send the synchronization signal from the base station over a low reuse channel shared by a group of base stations.

41. The wireless communications apparatus of claim 40, further comprising:

at least one processor configured to;

send the synchronization signal over the low reuse channel utilizing a subset of resources associated with coarse timing;

send the synchronization signal over at least one of the low reuse channel or a separate channel employing a subset of resources associated with fine timing when the clock of the base station provides at least a predetermined level of synchronous accuracy; and

inhibit sending the synchronization signal using the subset of resources associated with fine timing when the clock of the base station lacks at least the predetermined level of synchronous accuracy.

42. The wireless communications apparatus of claim 41, further comprising:

at least one processor configured to;

receive a disparate synchronization signal via the subset of resources associated with fine timing; and

tune the clock of the base station to the disparate synchronization signal.

43. An apparatus, comprising:

means for generating a synchronization signal as a function of a clock of a base station; and

means for sending the synchronization signal from the base station over a low reuse channel.

44. The apparatus of claim 43, further comprising means for sending the synchronization signal from the base station over the low reuse channel upon resources associated with fine timing as a function of a level of synchronous accuracy of the base station.

45. The apparatus of claim 43, further comprising means for tuning the clock of the base station based upon a disparate synchronization signal received upon resources associated with fine timing when the base station lacks at least a predetermined level of synchronous accuracy.

46. A computer program product, comprising:

a computer-readable medium comprising;

code for causing at least one computer to yield a synchronization signal as a function of a clock of a base station; and

code for causing at least one computer to transmit the synchronization signal from the base station over a low reuse channel shared by a plurality of base stations.

47. The computer program product of claim 46, wherein the computer-readable medium further comprises code for causing at least one computer to transmit the synchronization signal from the base station over the low reuse channel upon resources associated with fine timing as a function of a level of synchronous accuracy of the base station.

48. The computer program product of claim 46, wherein the computer-readable medium further comprises code for causing at least one computer to synchronize the clock of the base station to a disparate synchronization signal received upon resources associated with fine timing when the base station lacks at least a predetermined level of synchronous accuracy.

49. An apparatus, comprising:

a synchronization signal generation component that yields a synchronization signal based upon a clock of a transmitting base station; and

a transmission component that sends the synchronization signal from the transmitting base station over a low reuse channel shared by a group of base stations.

50. The apparatus of claim 49, wherein a first subset of base stations from the group transmit respective synchronization signals utilizing resources identified for a coordinated silence upon the low reuse channel and a second subset of base stations from the group forgo transmission of respective synchronization signals employing the resources identified for the coordinated silence upon the low reuse channel.