PREAMBLE CAPTURE AND MEDIUM ACCESS CONTROL

• US 20100157886A1
• Filed: 10/26/2007
• Published: 06/24/2010
• Est. Priority Date: 10/26/2007
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Ekbal, Amal, Julian, David Jonathan, Jia, Zhanfeng
• Granted Patent: US 9,083,448 B2
• Time in Patent Office: Days
• US Class Current: 370/328
• CPC Class Codes: H04B 1/7075 with code phase acquisition
• CPC Class Codes: H04B 1/7183 Synchronisation

Abstract

An apparatus and method for wireless communications configured to receive simultaneous transmissions from a plurality of wireless devices, with each of the transmissions having a reference signal, acquire the reference signals and, based on information obtained from the acquisition of the reference signals, select the transmission from one of the wireless devices for timing synchronization and decoding.

Claims

1. An apparatus for wireless communications, comprising:

a wireless interface configured to receive simultaneous transmissions from a plurality of wireless devices, each of the transmissions having a reference signal; and

a searcher configured to acquire the reference signals and, based on information obtained from the acquisition of the reference signals, select the transmission from one of the wireless devices for timing synchronization and decoding.

2. The apparatus of claim 1 wherein the searcher is further configured to distinguish between the wireless devices based on information obtained from the acquisition of the reference signals.

3. The apparatus of claim 2 wherein the reference signal in the transmission from each of the wireless devices includes a preamble sequence unique to that wireless device, and wherein the searcher is further configured to distinguish between the wireless devices based on the preamble sequences.

4. The apparatus of claim 2 wherein the searcher is further configured to distinguish between wireless devices by comparing the information obtained from the acquisition of the reference signals with information obtained from the acquisition of reference signals of previously received transmissions from the wireless devices.

5. The apparatus of claim 4 wherein the information being compared comprises energy, and wherein the searcher is further configured to compare the energy from each of the transmissions with the energy from each of the previously received transmissions to distinguish between the wireless devices.

6. The apparatus of claim 4 wherein the information being compared comprises delay spread, and wherein the searcher is further configured to compare the delay spread of each of the transmissions with the delay spread from each of the previously received transmissions to distinguish between the wireless devices.

7. The apparatus of claim 1 wherein the information comprises timing, and wherein the searcher is further configured to distinguish between wireless devices by identifying said one of the wireless devices based on timing of a previously received transmission from the same wireless device.

8. The apparatus of claim 1 wherein the searcher is further configured to select the transmission based on a fairness criterion with respect to previously received transmissions from the wireless devices.

9. The apparatus of claim 8 wherein the searcher is further configured to select the transmission from said one of the wireless devices whose previously received transmission was not selected.

10. The apparatus of claim 1 wherein the searcher is further configured to select the transmission based on at least one quality of service parameter.

11. The apparatus of claim 10 wherein the searcher is further configured to select the transmission from said one of the wireless devices based on the at least one quality of service parameter provided by said one of the wireless devices on a previously received transmission.

12. The apparatus of claim 1 wherein the searcher is further configured to acquire the reference signals before the end of a transmission from another one of the wireless devices being used for timing synchronization and decoding before the simultaneously transmissions from the wireless devices.

13. The apparatus of claim 1 wherein the searcher is further configured to generate an acknowledgement in response to selecting the transmission from said one of the wireless devices, and wherein the wireless interface is further configured to transmit the acknowledgement to said one of the wireless devices.

14. The apparatus of claim 1 wherein the wireless interface is further configured to transmit to said one of the wireless devices, the searcher being further configured to control the transmission by the wireless interface to said one of the wireless devices, receive an acknowledgement from said one of the wireless devices, and backoff a subsequent transmission by the wireless interface in response to the acknowledgement.

15. The apparatus of claim 1 wherein the searcher is further configured to select the transmission based on received energy from each of the simultaneous transmissions.

16. A method of wireless communications, comprising:

receiving simultaneous transmissions from a plurality of wireless devices, each of the transmissions having a reference signal;

acquiring the reference signals; and

selecting the transmission from one of the wireless devices for timing synchronization and decoding based on information obtained from the acquisition of the reference signals.

17. The method of claim 16 further comprising distinguishing between the wireless devices based on information obtained from the acquisition of the reference signals.

18. The method of claim 17 wherein the reference signal in the transmission from each of the wireless devices includes a preamble sequence unique to that wireless device, and wherein the wireless devices are distinguished based on the preamble sequences.

19. The method of claim 17 wherein the wireless devices are distinguished by comparing the information obtained from the acquisition of the reference signals with information obtained from the acquisition of reference signals of previously received transmissions from the wireless devices.

20. The method of claim 19 wherein the information being compared comprises energy, and wherein the wireless devices are distinguished by comparing the energy from each of the transmissions with the energy from each of the previously received transmissions.

21. The method of claim 19 wherein the information being compared comprises delay spread, and wherein the wireless devices are distinguished by comparing the delay spread of each of the transmissions with the delay spread from each of the previously received transmissions.

22. The method of claim 16 wherein the information comprises timing, and wherein the wireless devices are distinguished by identifying said one of the wireless devices based on timing of a previously received transmission from the same wireless device.

23. The method of claim 16 wherein the selection of the transmission is based on a fairness criterion with respect to previously received transmissions from the wireless devices.

24. The method of claim 23 wherein the transmission from said one of the wireless devices is selected whose previously received transmission was not selected.

25. The method of claim 16 wherein the selection of the transmission is based on at least one quality of service parameter.

26. The method of claim 25 wherein the selection of the transmission from said one of the wireless devices based on the at least one quality of service parameter provided by said one of the wireless devices on a previously received transmission.

27. The method of claim 16 wherein the reference signals are acquired before the end of a transmission from another one of the wireless devices being used for timing synchronization and decoding before the simultaneously transmissions from the wireless devices.

28. The method of claim 16 further comprising generating an acknowledgement in response to selecting the transmission from said one of the wireless devices, and transmitting the acknowledgement to said one of the wireless devices.

29. The method of claim 16 further comprising transmitting to said one of the wireless devices, receiving an acknowledgement from said one of the wireless devices, and backing off a subsequent transmission in response to the acknowledgement.

30. The method claim 16 wherein the transmission from said one of the wireless devices is selected based on received energy from each of the simultaneous transmissions.

31. An apparatus for wireless communications, comprising:

means for receiving simultaneous transmissions from a plurality of wireless devices, each of the transmissions having a reference signal;

means for acquiring the reference signals; and

means for selecting the transmission from one of the wireless devices for timing synchronization and decoding based on information obtained from the acquisition of the reference signals.

32. The apparatus of claim 31 further comprising means for distinguishing between the wireless devices based on information obtained from the acquisition of the reference signals.

33. The apparatus of claim 32 wherein the reference signal in the transmission from each of the wireless devices includes a preamble sequence unique to that wireless device, and wherein the means for distinguishing between wireless devices is configured to distinguish between the wireless devices based on the preamble sequences.

34. The apparatus of claim 32 wherein the means for distinguishing between wireless devices is configured to distinguish between the wireless devices by comparing the information obtained from the acquisition of the reference signals with information obtained from the acquisition of reference signals of previously received transmissions from the wireless devices.

35. The apparatus of claim 34 wherein the information being compared comprises energy, and wherein the means for distinguishing between wireless devices is configured to distinguish between the wireless devices by comparing the energy from each of the transmissions with the energy from each of the previously received transmissions.

36. The apparatus of claim 34 wherein the information being compared comprises delay spread, and wherein the means for distinguishing between wireless devices is configured to distinguish between the wireless devices by comparing the delay spread of each of the transmissions with the delay spread from each of the previously received transmissions.

37. The apparatus of claim 31 wherein the information comprises timing, and wherein the means for distinguishing between wireless devices is configured to distinguish between the wireless devices by identifying said one of the wireless devices based on timing of a previously received transmission from the same wireless device.

38. The apparatus of claim 31 wherein the means for selecting the transmission is configured to select the transmission based on a fairness criterion with respect to previously received transmissions from the wireless devices.

39. The apparatus of claim 38 wherein the means for selecting the transmission is configured to select the transmission from said one of the wireless devices whose previously received transmission was not selected.

40. The apparatus of claim 31 wherein the means for selecting the transmission is configured to select the transmission based on at least one quality of service parameter.

41. The apparatus of claim 40 wherein the means for selecting the transmission is configured to select the transmission based on the at least one quality of service parameter provided by said one of the wireless devices on a previously received transmission.

42. The apparatus of claim 31 wherein the means for acquiring the reference signals is configured to acquire the reference signals before the end of a transmission from another one of the wireless devices being used for timing synchronization and decoding before the simultaneously transmissions from the wireless devices.

43. The apparatus of claim 31 further comprising means for generating an acknowledgement in response to selecting the transmission from said one of the wireless devices, and means for transmitting the acknowledgement to said one of the wireless devices.

44. The apparatus of claim 31 further comprising means for transmitting to a receiving one of the wireless devices, means for receiving an acknowledgement from said receiving one of the wireless devices, and means for backing off a subsequent transmission in response to the acknowledgement.

45. The apparatus of claim 31 wherein the means for selecting the transmission is configured to select the transmission based on received energy from each of the simultaneous transmissions.

46. A computer-program product for wireless communications comprising simultaneously transmissions received from a plurality of wireless devices, each of the transmissions having a reference signal, the computer-program product, comprising:

computer-readable medium comprising codes executable by at least one processor to;

acquire the reference signals; and

select the transmission from one of the wireless devices for timing synchronization and decoding based on information obtained from the acquisition of the reference signals.

47. A headset, comprising:

a wireless interface configured to receive simultaneous transmissions from a plurality of wireless devices, each of the transmissions having a reference signal;

a searcher configured to acquire the reference signals and, based on information obtained from the acquisition of the reference signals, select the transmission from one of the wireless devices for timing synchronization and decoding; and

a transducer configured to provide an audio output based on the selected transmission.

48. A watch comprising:

a wireless interface configured to receive simultaneous transmissions from a plurality of wireless devices, each of the transmissions having a reference signal;

a searcher configured to acquire the reference signals and, based on information obtained from the acquisition of the reference signals, select the transmission from one of the wireless devices for timing synchronization and decoding; and

a user interface configured to provide an indication based on the selected transmission.

49. A sensing device for wireless communications, comprising:

a wireless interface configured to receive simultaneous transmissions from a plurality of wireless devices, each of the transmissions having a reference signal;

a searcher configured to acquire the reference signals and, based on information obtained from the acquisition of the reference signals, select the transmission from one of the wireless devices for timing synchronization and decoding; and

a sensor configured to provide data to the wireless interface for transmission.