Pilot signal transmission for an orthogonal frequency division wireless communication system

• US 20060209670A1
• Filed: 03/17/2005
• Published: 09/21/2006
• Est. Priority Date: 03/17/2005
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Gore, Dhananjay Ashok, Naguib, Ayman Fawzy, Gorokhov, Alexei, Sutivong, Arak, Ji, Tingfang
• Granted Patent: US 9,143,305 B2
• Time in Patent Office: Days
• US Class Current: 370/208
• CPC Class Codes: H04L 27/261 Details of reference signals
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0039 Frequency-contiguous, i.e. with no allocation of frequencies for one user or terminal between the frequencies allocated to another
• CPC Class Codes: H04L 5/0051 of dedicated pilots, i.e. pilots destined for a single user or terminal
• CPC Class Codes: H04L 5/0062 Avoidance of ingress interference, e.g. ham radio channels
• CPC Class Codes: H04L 5/023 Multiplexing of multicarrier modulation signals multicarrier modulation H04L27/2601

Abstract

Transmission patterns for pilot symbols transmitted from a mobile station or base station are provided. The pattern allows for improved receipt of the pilot symbols transmitted. In addition, schemes for improving the ability to multiplex pilot symbols without interference and/or biasing from different mobile stations over the same frequencies and in the same time slots.

Claims

1. A wireless communication apparatus, comprising:

at least one antenna;

a memory that stores a pattern of pilot symbols to be transmitted from the wireless communication device and a plurality of scalar functions; and

a processor coupled with the at least one antenna and the memory, the processor causing the samples comprising the pilot symbols to be multiplied by a group of the plurality of scalar functions prior to transmission of the pilot symbols from the antenna.

2. The wireless communication apparatus of claim 1, wherein the memory stores another plurality of scalar functions and wherein the processor causes the samples to be multiplied by the group of both the plurality of scalar functions and a group of the another plurality of scalar functions.

3. The wireless communication apparatus of claim 2, wherein the another plurality of scalar functions comprise vectors of scalar functions and wherein each vector is orthogonal to each other vector.

4. The wireless communication apparatus of claim 1, wherein the plurality of scalar functions comprise vectors of scalar functions and wherein each vector is orthogonal to each other vector.

5. The wireless communication apparatus of claim 1, wherein the plurality of pilot patterns comprise pilot symbol clusters.

6. The wireless communication apparatus of claim 5, wherein the wireless communication apparatus transmits signals using a plurality of frequency subcarriers in a frequency range between a maximum frequency and a minimum frequency and wherein the pilot symbol clusters each comprises a plurality of pilot symbols so that at least one the plurality of pilot symbols of each of the plurality of clusters is transmitted using a frequency subcarrier other than the maximum frequency or the minimum frequency.

7. The wireless communication apparatus of claim 6, wherein the processor varies the frequency range between a first time period and a second time period so that no frequencies within the frequency range for the first time period are within the frequency range for a second time period.

8. The wireless communication apparatus of claim 5, wherein the wireless communication apparatus transmits signals using a plurality of contiguous symbol periods between a first symbol period and a last symbol period and wherein the pilot symbol clusters each comprises a plurality of pilot symbols so that only one of the plurality of pilot symbols of each of the plurality of clusters is transmitted during either the first symbol period or the last symbol period.

9. The wireless communication apparatus of claim 1, wherein the plurality of pilot symbols comprise a plurality of time selective pilot symbol clusters and frequency selective pilot symbol clusters.

10. The wireless communication apparatus of claim 1, wherein each of the plurality of scalar multiples consists of a phase shift to each sample of each symbol.

11. The wireless communication apparatus of claim 1, wherein the plurality of scalar functions comprise vectors of scalar functions and wherein each vector is quasi-orthogonal to each other vector.

12. The wireless communication apparatus of claim 1, wherein processor multiplies the vectors of scalar functions and the pilot symbols utilizing a discrete Fourier transform.

13. A method for wireless communication comprising:

generating a plurality of pilot symbols to be transmitted from a wireless communication device; and

applying one of a plurality of scalar function to each of the plurality of pilot symbols.

14. The method of claim 13, wherein the plurality of scalar functions are grouped in vectors and wherein each vector is orthogonal to each other vector.

15. The method of claim 13, wherein applying comprising shifting a phase of each sample that comprises each pilot symbol according to the scalar function.

16. The method of claim 13, further comprising applying another scalar function of another plurality of scalar functions to each of the plurality of pilot symbols.

17. The method of claim 16, wherein applying another scalar function comprises varying over time the another scalar function applied to a pilot symbol of the plurality of pilot symbols.

18. The method of claim 13, wherein the plurality of pilot symbols are transmitted utilizing a plurality of subcarriers between a maximum frequency and a minimum frequency, the method further comprising

grouping the plurality of pilot symbols into clusters;

and

assigning a transmission frequency to each pilot symbol of each cluster so that at least one pilot symbol of each cluster is assigned a subcarrier other than the maximum frequency and the minimum frequency.

19. The method of claim 13, wherein the plurality of scalar functions comprise scalar functions are unique to the wireless communication device.

20. The method of claim 13, wherein the plurality of scalar functions comprise scalar functions are unique to a sector of a base station with which the wireless communication device communicates.

21. The method of claim 13, wherein the plurality of scalar functions comprise vectors of scalar functions and wherein each vector is quasi-orthogonal to each other vector.

22. The method of claim 13, wherein applying the plurality of scalar functions comprises utilizing a discrete Fourier transform in applying the scalar functions.

23. A method of wireless communication, comprising:

grouping a first plurality of pilot symbols into a plurality of clusters;

applying, at the first wireless communication device, a first plurality of scalar functions to the first plurality of pilot symbols;

transmitting, from the first wireless communication device, the plurality of pilot symbols during a plurality of time intervals and at a plurality of frequencies;

grouping a second plurality of pilot symbols into a plurality of clusters;

applying, at a second wireless communication device, a second plurality of scalar functions different than the first plurality of scalar functions to a second plurality of pilot symbols, wherein each cluster of the plurality of first pilot symbols is orthogonal to each other cluster of the plurality of first pilot symbols and the plurality of second pilot symbols; and

transmitting, from the second wireless communication device, the second plurality of pilot symbols during the same plurality of time intervals and at the same plurality of frequencies as the plurality of first pilot symbols.

24. The method claim 23, wherein the plurality of pilot symbols are transmitted utilizing a plurality of subcarriers between a maximum frequency and a minimum frequency and wherein transmitting, from the first wireless communication device, comprises transmitting each cluster of the first plurality of pilot symbols so that at least one pilot symbol of each cluster is assigned a subcarrier that is one other than the maximum frequency and the minimum frequency.

25. The method of claim 23, wherein the maximum frequency and the minimum frequency vary between a first time period and a second time period so that no frequencies between the minimum frequency and the maximum frequency for the first time period are between the minimum frequency and the maximum frequency for the second time period.

26. The method of claim 23, wherein the plurality of pilot symbols are transmitted during a plurality of contiguous symbol periods between a first symbol period and a last symbol period and wherein groups of pilot symbols each comprises a plurality of pilot symbols so that only one of the plurality of pilot symbols of each group is transmitted during either the first symbol period or the last symbol period.

27. The method of claim 23, further comprising applying another scalar function of another plurality of scalar functions to each of the plurality of first pilot symbols.

28. The method of claim 27, wherein applying another scalar function comprises varying over time the another scalar function applied to each of the plurality of first pilot symbols.

29. The method of claim 28, further comprising selecting the first plurality of scalar functions based upon a sector of a base station to which the first wireless communication device is transmitting.

30. The method of claim 28, wherein the first plurality of scalar functions is unique to the first wireless communication device.

31. The method of claim 23, wherein the first plurality of scalar functions comprise vectors of scalar functions and wherein each vector is quasi-orthogonal to each other vector.

32. The method of claim 23, wherein applying, at the first wireless communication device, a first plurality of scalar functions comprises utilizing a discrete Fourier transform in applying the first plurality of scalar functions.

33. A wireless communication apparatus, comprising:

a plurality of antennas;

a memory that stores a plurality of pilot patterns each comprising a plurality of clusters each of which comprises a plurality of pilot symbols, each cluster of the plurality of clusters in a same pilot pattern being orthogonal to each other cluster of the plurality of clusters of the same pilot pattern; and

a processor coupled with the plurality of antennas and the memory, the processor utilizing one pilot pattern of the plurality of pilot patterns to decode multiple pilot symbol groups received from a plurality of wireless devices at the plurality of antennas.

34. The wireless communication apparatus of claim 33, wherein the plurality of pilot patterns comprise at least one time selective pilot pattern and at least one frequency selective pilot pattern.

35. The wireless communication apparatus of claim 33, wherein the memory further stores a plurality of sequences that are orthogonal to each other sequence of the plurality of sequences and wherein the processor selectively instructs multiplication of the pilot symbols of the pilot pattern with some of the sequences of the plurality of sequences prior to decoding the pilot symbols.

36. The wireless communication apparatus of claim 33, wherein the memory further stores another plurality of sequences and wherein the processor selectively instructs multiplication of the pilot symbols of the pilot pattern with both some of the sequences of the plurality of sequences and some of the another plurality of sequences prior to decoding the pilot symbols.

37. The wireless communication apparatus of claim 36, wherein the processor generates an instruction, to be transmitted from at least one of the plurality of antennas, specifying a pilot pattern of the plurality of pilot patterns to be transmitted to the wireless communication apparatus.

38. The wireless communication apparatus of claim 33, wherein each pilot symbol of each pilot symbol pattern is assigned to a frequency within a frequency range between a maximum frequency and a minimum frequency and wherein at least one the plurality of pilot symbols of each of the plurality of clusters is assigned to a frequency subcarrier other than the maximum frequency or the minimum frequency.

39. The wireless communication apparatus of claim 33, wherein each pilot symbol of each pilot symbol pattern is assigned to a symbol period of a plurality of contiguous symbol periods between a first symbol period and a last symbol period and wherein only one of the plurality of pilot symbols of each of the plurality of clusters is assigned either the first symbol period or the last symbol period.

40. The wireless communication apparatus of claim 33, wherein each of the pilot symbols of each cluster are assigned to be transmitted utilizing a frequency subcarrier of a group of contiguous frequency subcarriers that range from a minimum frequency to a maximum frequency and during a symbol period of a group of contiguous symbol periods that range from a first symbol period to a last symbol period and wherein in each cluster no more than one pilot symbol is assigned the maximum frequency or the minimum frequency as its transmission frequency subcarrier or the first symbol period or the last symbol period as its transmission symbol period.

41. A wireless communication apparatus, comprising:

at plurality of antennas;

a memory that stores a plurality of pilot patterns each of which comprises a plurality of clusters, each cluster of the plurality of clusters in a same pilot pattern being orthogonal to each other cluster of the plurality of clusters of the same pilot pattern; and

a processor coupled with the plurality of antennas and the memory, the processor causing a plurality of pilot symbols according to one pilot pattern of the plurality of pilot patterns to be transmitted from at least two of the plurality of antennas.

42. The wireless communication apparatus of claim 41, wherein the processor causes a plurality of pilot symbols according to another pilot pattern, different than the one pilot pattern, of the plurality of pilot patterns to be transmitted from at least two of the plurality of antennas.

43. The wireless communication apparatus of claim 41, wherein the plurality of pilot patterns comprise at least one time selective pilot pattern and at least one frequency selective pilot pattern.

44. The wireless communication apparatus of claim 41, wherein the memory further stores a plurality of sequences that are orthogonal to each other sequence of the plurality of sequences and wherein the processor selectively instructs multiplication of the pilot symbols of the pilot pattern with some of the sequences of the plurality of sequences prior to transmitting the plurality of pilot symbols according to one pilot pattern.

45. The wireless communication apparatus of claim 41, wherein the memory further stores another plurality of sequences and wherein the processor selectively instructs multiplication of the pilot symbols of the pilot pattern with both some of the sequences of the plurality of sequences and some of the another plurality of sequences prior to transmitting the plurality of pilot symbols according to one pilot pattern.

46. The wireless communication apparatus of claim 45, wherein the processor generates an instruction, to be transmitted from at least one of the plurality of antennas, specifying a pilot pattern of the plurality of pilot patterns to be transmitted to the wireless communication apparatus.

47. The wireless communication apparatus of claim 41, wherein each pilot symbol of each pilot symbol pattern is assigned to a frequency within a frequency range between a maximum frequency and a minimum frequency and wherein at least one the plurality of pilot symbols of each of the plurality of clusters is assigned to a frequency subcarrier other than the maximum frequency or the minimum frequency.

48. The wireless communication apparatus of claim 41, wherein each pilot symbol of each pilot symbol pattern is assigned to a symbol period of a plurality of contiguous symbol periods between a first symbol period and a last symbol period and wherein only one of the plurality of pilot symbols of each of the plurality of clusters is assigned to either the first symbol period or the last symbol period.

49. The wireless communication apparatus of claim 41, wherein each of the pilot symbols of each cluster are assigned to be transmitted utilizing a frequency subcarrier of a group of contiguous frequency subcarriers that range from a minimum frequency to a maximum frequency and during a symbol period of a group of contiguous symbol periods that range from a first symbol period to a last symbol period and wherein in each cluster no more than one pilot symbol is assigned the maximum frequency or the minimum frequency as its transmission frequency subcarrier or the first symbol period or the last symbol period as its transmission symbol period.

50. A wireless communication apparatus comprising:

means for arranging a plurality of pilot symbols in a plurality of clusters; and

applying one a plurality of scalar functions to each of the plurality of pilot symbols prior to transmission of the pilot symbol.

51. The wireless communication apparatus of claim 50, wherein the means for applying comprises means for applying the plurality of scalar functions so that each cluster of pilot symbols is orthogonal to each other cluster of pilot symbols.

52. The wireless communication apparatus of claim 50, further comprising means for applying another scalar function of another plurality of scalar functions to each of the plurality of pilot symbols.

53. The wireless communication apparatus of claim 50, wherein applying another scalar function comprises varying over time the another scalar function applied to a pilot symbol of the plurality of pilot symbols.

54. The wireless communication apparatus of claim 50, wherein the plurality of scalar functions comprise scalar functions are unique to the wireless communication device.

55. The wireless communication apparatus of claim 50, wherein the plurality of scalar functions comprise scalar functions are unique to a sector of a base station with which the wireless communication device communicates.

56. The wireless communication apparatus of claim 50, wherein the plurality of pilot symbols are transmitted utilizing a plurality of subcarriers between a maximum frequency and a minimum frequency and wherein the means for arranging comprises means for assigning a transmission frequency to each pilot symbol of each cluster so that at least one pilot symbol of each cluster is assigned a subcarrier that is one other than the maximum frequency and the minimum frequency.

57. The wireless communication apparatus of claim 50, wherein the plurality of pilot symbols are transmitted during a plurality of contiguous symbol periods between a first symbol period and a last symbol period and wherein the means for arranging comprises means for assigning each pilot symbol to a symbol period so that so that at only one pilot symbol of each cluster is transmitted during either the first symbol period or the last symbol period.

58. A wireless communication apparatus comprising:

;

means for grouping a first plurality of pilot symbols into a plurality of clusters;

means for applying, at the first wireless communication device, a first plurality of scalar functions to the first plurality of pilot symbols;

means for transmitting, from the first wireless communication device, the plurality of pilot symbols during a plurality of time intervals and at a plurality of frequencies;

means for grouping a second plurality of pilot symbols into a plurality of clusters;

means for applying, at a second wireless communication device, a second plurality of scalar functions different than the first plurality of scalar functions to a second plurality of pilot symbols, wherein each cluster of the plurality of first pilot symbols is orthogonal to each other cluster of the plurality of first pilot symbols and the plurality of second pilot symbols; and

means for transmitting, from the second wireless communication device, the second plurality of pilot symbols during the same plurality of time intervals and at the same plurality of frequencies as the plurality of first pilot symbols.

59. The wireless communication apparatus of claim 58, wherein the plurality of pilot symbols are transmitted utilizing a plurality of subcarriers between a maximum frequency and a minimum frequency and wherein the means for transmitting, from the first wireless communication device, comprises means for transmitting each cluster of the first plurality of pilot symbols so that at least one pilot symbol of each cluster is assigned a subcarrier that is one other than the maximum frequency and the minimum frequency.

60. The wireless communication apparatus of claim 59, wherein means for transmitting varies the maximum frequency and the minimum frequency vary between a first time period and a second time period so that no frequencies between the minimum frequency and the maximum frequency for the first time period are between the minimum frequency and the maximum frequency for the second time period.

61. The wireless communication apparatus of claim 58, wherein the plurality of pilot symbols are transmitted during a plurality of contiguous symbol periods between a first symbol period and a last symbol period and wherein means for grouping comprises means for grouping the plurality of pilot symbols so that only one of the plurality of pilot symbols of each group is transmitted during either the first symbol period or the last symbol period.

62. The wireless communication apparatus of claim 58, further comprising means for applying another scalar function of another plurality of scalar functions to each of the plurality of first pilot symbols.

63. The wireless communication apparatus of claim 58, wherein the means for applying another scalar function comprises means for varying over time the another scalar function applied to each of the plurality of first pilot symbols.