Multiplexing of real time services and non-real time services for OFDM systems

• US 20060023666A1
• Filed: 06/23/2005
• Published: 02/02/2006
• Est. Priority Date: 03/22/2000
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Walton, Jay Rodney, Jalali, Ahmad
• Granted Patent: US 7,751,492 B2
• Time in Patent Office: Days
• US Class Current: 370/334
• CPC Class Codes: H04L 27/26 Systems using multi-frequency codes H04L27/32 takes precedence
• CPC Class Codes: H04L 5/023 Multiplexing of multicarrier modulation signals multicarrier modulation H04L27/2601

Abstract

Transmitter and receiver units for use in an OFDM communications system and configurable to support multiple types of services. The transmitter unit includes one or more encoders, a symbol mapping element, and a modulator. Each encoder receives and codes a respective channel data stream to generate a corresponding coded data stream. The symbol mapping element receives and maps data from the coded data streams to generate modulation symbol vectors, with each modulation symbol vector including a set of data values used to modulate a set of tones to generate an OFDM symbol. The modulator modulates the modulation symbol vectors to provide a modulated signal suitable for transmission. The data from each coded data stream is mapped to a respective set of one or more “circuits”. Each circuit can be defined to include a number of tones from a number of OFDM symbols, a number of tones from a single OFDM symbol, all tones from one or more OFDM symbols, or some other combination of tones. The circuits can have equal size or different sizes. Different circuits can be used for full rate data (e.g., active speech) and low rate data (e.g., silence periods).

Claims

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62. The apparatus of claim 61, wherein the Walsh sequences have a length of 1/W chips.

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21. A method of generating pilots in a wireless multiple-input multiple output (MIMO) communication system, comprising:

obtaining at least one pilot symbol for each antenna of a plurality of antennas;

obtaining an orthogonal sequence for each antenna in the plurality of antennas; and

covering the at least one pilot symbol for each antenna with the orthogonal sequence to obtain a sequence of covered pilot symbols for each antenna to obtain at least one covered pilot symbols for each of the plurality of antennas.

22. The method of claim 21, wherein obtaining the orthogonal sequence comprises obtaining a different orthogonal sequence for each antenna.

23. The method of claim 21, further comprising transmitting the plurality of orthogonal pilots from the plurality of antennas.

24. The method of claim 21, wherein the orthogonal sequences are Walsh sequences.

25. The method of claim 24, wherein the Walsh sequences have a length of 1/W chips.

26. The method of claim 21, wherein obtaining at least one pilot symbol comprises obtaining a same at least one pilot symbol for each of the plurality of antennas.

27. The method of claim 21, further comprising transmitting at least one covered pilot symbol on each antenna from a predetermined set of subbands.

28. The method of claim 21, further comprising transmitting the sequence of covered pilot symbols during predetermined time slots.

29. The method of claim 21, further comprising applying a cyclic prefix to each covered pilot symbol.

30. An wireless communication apparatus comprising:

a plurality of antennas;

means for obtaining at least one pilot symbol for each antenna in the plurality of antennas;

means for obtaining an orthogonal sequence for each antenna in the plurality of antennas; and

means for covering the pilot symbol for each antenna with the orthogonal sequence to obtain a sequence of covered pilot symbols for the antenna.

31. The apparatus of claim 30, wherein the means for obtaining the orthogonal sequence comprises means for obtaining a different orthogonal sequence for each antenna.

32. The apparatus of claim 30, wherein the orthogonal sequences are Walsh sequences.

33. The apparatus of claim 32, wherein the Walsh sequences have a length of 1/W chips.

34. The apparatus of claim 30, further comprising means for designating transmission of the covered pilot symbols on a predetermined set of subbands.

35. The apparatus of claim 30, further comprising means for transmitting the sequence of covered pilot symbols during predetermined time slots.

36. The apparatus of claim 30, further comprising means for applying a cyclic prefix to each pilot symbol.

37. An wireless communication apparatus comprising:

a plurality of antennas;

a plurality of modulators coupled to the plurality of antennas; and

a sit data processor, coupled to the plurality of modulators, that provides a plurality of covered pilot symbol for each antenna, wherein each covered pilot symbol is generated by covering a pilot symbol with an orthogonal sequence.

38. The apparatus of claim 37, wherein a different orthogonal sequence is used for each antenna.

39. The apparatus of claim 37, wherein the orthogonal sequences are Walsh sequences.

40. The apparatus of claim 39, wherein the Walsh sequences have a length of 1/W chips.

41. The apparatus of claim 37, wherein the pilot symbols are transmitted on a predetermined set of subbands.

42. The apparatus of claim 37, wherein the modulators apply a cyclic prefix to each pilot symbol.

43. The apparatus of claim 37, wherein the sequence of covered pilot symbols are transmitted during predetermined time slots.

44. A method of generating pilots in a wireless multiple-input multiple output (MIMO) communication system, comprising:

generating at least one pilot symbol for each antenna of a plurality of antennas; and

applying an orthogonal sequence to each pilot symbol for each antenna to obtain orthogonal pilot symbols for each antenna.

45. The method of claim 44, further comprising generating a different orthogonal sequence for each antenna so that the pilot symbols of each antenna are orthogonal to pilot symbols of each other antenna

46. The method of claim 44, further comprising transmitting the plurality of orthogonal pilot symbols from the plurality of antennas.

47. The method of claim 44, wherein the orthogonal sequences are Walsh sequences.

48. The method of claim 47, wherein the Walsh sequences have a length of 1/W chips.

49. The method of claim 44, wherein obtaining comprises obtaining a same pilot symbol for the plurality of antennas.

50. The method of claim 44, wherein the pilot symbols are transmitted during predetermined time slots.

51. The method of claim 44, further comprising applying a cyclic prefix to each pilot symbol.

52. An wireless communication apparatus comprising:

a plurality of antennas;

means for generating at least one pilot symbol for each antenna of a plurality of antennas; and

means for applying an orthogonal sequence to each pilot symbol for each antenna to obtain orthogonal pilot symbols for each antenna.

53. The apparatus of claim 52, further comprising means for obtaining a different orthogonal sequence for each antenna.

54. The apparatus of claim 52, wherein the orthogonal sequences are Walsh sequences.

55. The apparatus of claim 54, wherein the Walsh sequences have a length of 1/W chips.

56. The apparatus of claim 52, further comprising means for designating transmission of the orthogonal pilot symbols on a predetermined set of subbands.

57. The apparatus of claim 52, further comprising means for applying a cyclic prefix to each pilot symbol.

58. The apparatus of claim 52, further comprising means for transmitting the orthogonal pilot symbols during predetermined time slots.

59. An wireless communication apparatus comprising:

a plurality of antennas;

a plurality of modulators coupled to the plurality of antennas; and

a transmit data processor, coupled to the plurality of modulators, tat provides a plurality of orthogonal pilot symbol for each antenna, so that each pilot symbol for each antenna is orthogonal to the pilot symbols of the other antennas.

60. The apparatus of claim 59, wherein a different orthogonal sequence is used for each antenna.

61. The apparatus of claim 59, wherein the orthogonal sequences are Walsh sequences.

63. The apparatus of claim 59, wherein the pilot symbols are transmitted on a predetermined set of subbands.

64. The apparatus of claim 59, wherein the modulators apply a cyclic prefix to each pilot symbol.