SYSTEMS AND METHODS FOR TRANSMITTING PILOT TONES

• US 20130266086A1
• Filed: 12/06/2012
• Published: 10/10/2013
• Est. Priority Date: 04/05/2012
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Yang, Lin, Van Nee, Didier Johannes Richard, Sampath, Hemanth, Vermani, Sameer, Tian, Tao
• Granted Patent: US 9,774,481 B2
• Time in Patent Office: Days
• US Class Current: 375/295
• CPC Class Codes: H04L 27/10 Frequency-modulated carrier systems, i.e. using frequency-shift keying H04L27/32 takes precedence
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver

Abstract

Systems and methods for using travelling pilots for channel estimation are described herein. In one aspect, wireless communications apparatus is described that comprises a processor configured to divide a plurality of tones on which pilot signals are to be transmitted among a plurality of symbols, wherein each symbol includes less than all of the plurality of tones and the plurality of symbols includes at least a subset of the plurality of tones. The wireless communication apparatus further comprises a transmitter configured to transmit, during a given symbol, pilot signals on the tones included in the given symbol, wherein the tones over which the pilot signals are transmitted are changed from symbol to symbol.

Claims

1. A wireless communications apparatus comprising:

a processor configured to divide a plurality of tones on which pilot signals are to be transmitted among a plurality of symbols, wherein each symbol includes less than all of the plurality of tones and the plurality of symbols includes at least a subset of the plurality of tones; and

a transmitter configured to transmit, during a given symbol, pilot signals on the tones included in the given symbol, wherein the tones over which the pilot signals are transmitted are changed from symbol to symbol.

2. The wireless communications apparatus of claim 1, wherein the subset of the plurality of tones comprises half of the tones.

3. The wireless communications apparatus of claim 2, wherein the half of the tones comprises either even-numbered tones or odd-numbered tones.

4. The wireless communications apparatus of claim 1, wherein the plurality of symbols includes all of the plurality of tones.

5. The wireless communications apparatus of claim 4, wherein the processor is further configured to divide the plurality of symbols into a plurality of groups.

6. The wireless communications apparatus of claim 5, wherein the transmitter is further configured to transmit the pilot signals during the symbols of a first group of the plurality of groups, wherein channel estimation is performed based on the first group of the plurality of groups.

7. The wireless communications apparatus of claim 4, wherein one of symbols of the plurality of symbols is repeated in the plurality of symbols.

8. The wireless communications apparatus of claim 4, wherein the transmitter is further configured to transmit the plurality of symbols sequentially and in a round robin fashion.

9. The wireless communications apparatus of claim 4, wherein the tones are divided among the symbols based on at least one of the following criteria:

maximizing intra-symbol distances between tones, and maximizing inter-symbol distances between tones.

10. A method of communicating in a wireless network, the method comprising:

dividing a plurality of tones on which pilot signals are to be transmitted among a plurality of symbols, wherein each symbol includes less than all of the plurality of tones and the plurality of symbols includes at least a subset of the plurality of tones; and

transmitting, during a given symbol, pilot signals on the tones included in the given symbol, wherein the tones over which the pilot signals are transmitted are changed from symbol to symbol.

11. The method of claim 10, wherein the subset of the plurality of tones comprises half of the tones.

12. The method of claim 11, wherein the half of the tones comprises either the even-numbered tones or the odd-numbered tones.

13. The method of claim 10, wherein the plurality of symbols includes all of the plurality of tones.

14. The method of claim 13, further comprising dividing the plurality of symbols into a plurality of groups.

15. The method of claim 14, further comprising transmitting the pilot signals during the symbols of a first group of the plurality of groups, wherein channel estimation is performed based on the first group of the plurality of groups.

16. The method of claim 13, wherein one of symbols of the plurality of symbols is repeated in the plurality of symbols.

17. The method of claim 13, further comprising transmitting the plurality of symbols sequentially and in a round robin fashion.

18. The method of claim 13, wherein the tones are divided among the symbols based on at least one of the following criteria:

maximizing intra-symbol distances between tones, and maximizing inter-symbol distances between tones.

19. A wireless communications apparatus comprising:

means for dividing a plurality of tones on which pilot signals are to be transmitted among a plurality of symbols, wherein each symbol includes less than all of the plurality of tones and the plurality of symbols includes at least a subset of the plurality of tones; and

means for transmitting, during a given symbol, pilot signals on the tones included in the given symbol, wherein the tones over which the pilot signals are transmitted are changed from symbol to symbol.

20. The wireless communications apparatus of claim 19, wherein the subset of the plurality of tones comprises half of the tones.

21. The wireless communications apparatus of claim 20, wherein the half of the tones comprises either the even-numbered tones or the odd-numbered tones.

22. The wireless communications apparatus of claim 19, wherein the plurality of symbols includes all of the plurality of tones.

23. The wireless communications apparatus of claim 22, wherein the means for dividing is further configured to divide the plurality of symbols into a plurality of groups.

24. The wireless communications apparatus of claim 23, wherein the means for transmitting is further configured to transmit the pilot signals during the symbols of a first group of the plurality of groups, wherein channel estimation is performed based on the first group of the plurality of groups.

25. The wireless communications apparatus of claim 22, wherein one of symbols of the plurality of symbols is repeated in the plurality of symbols.

26. The wireless communications apparatus of claim 22, wherein the means for transmitting is further configured to transmit the plurality of symbols sequentially and in a round robin fashion.

27. The wireless communications apparatus of claim 22, wherein the tones are divided among the symbols based on at least one of the following criteria:

maximizing intra-symbol distances between tones, and maximizing inter-symbol distances between tones.

28. A computer program product, comprising:

a computer-readable medium comprising;

code for dividing a plurality of tones on which pilot signals are to be transmitted among a plurality of symbols, wherein each symbol includes less than all of the plurality of tones and the plurality of symbols includes at least a subset of the plurality of tones; and

code for transmitting, during a given symbol, pilot signals on the tones included in the given symbol, wherein the tones over which the pilot signals are transmitted are changed from symbol to symbol.

29. The computer program product of claim 28, wherein the subset of the plurality of tones comprises half of the tones.

30. The computer program product of claim 29, wherein the half of the tones comprises either the even-numbered tones or the odd-numbered tones.

31. The computer program product of claim 28, wherein the plurality of symbols includes all of the plurality of tones.

32. The computer program product of claim 31, wherein the computer-readable medium further comprises code for dividing the plurality of symbols into a plurality of groups.

33. The computer program product of claim 32, wherein the computer-readable medium further comprises code for transmitting the pilot signals during the symbols of a first group of the plurality of groups, wherein channel estimation is performed based on the first group of the plurality of groups.

34. The computer program product of claim 31, wherein one of symbols of the plurality of symbols is repeated in the plurality of symbols.

35. The computer program product of claim 31, wherein the computer-readable medium further comprises code for transmitting the plurality of symbols sequentially and in a round robin fashion.

36. The computer program product of claim 31, wherein the tones are divided among the symbols based on at least one of the following criteria:

maximizing intra- symbol distances between tones, and maximizing inter-symbol distances between tones.