MC-CDMA MULTIPLEXING IN AN ORTHOGONAL UPLINK

• US 20110064039A1
• Filed: 09/23/2010
• Published: 03/17/2011
• Est. Priority Date: 12/22/2004
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Agrawal, Avneesh, Sutivong, Arak
• Granted Patent: US 8,817,897 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04B 1/692 Hybrid techniques using combinations of two or more spread spectrum techniques
• CPC Class Codes: H04B 1/713 using frequency hopping
• CPC Class Codes: H04J 13/18 Allocation of orthogonal codes
• CPC Class Codes: H04L 5/0021 in which codes are applied as a frequency-domain sequences, e.g. MC-CDMA

Abstract

Techniques are provided to support multi-carrier code division multiple access (MC-CDMA) in an orthogonal uplink of a wireless communication system. A method of wireless multi-carrier communications comprises dividing sub-carriers on an uplink into non-overlapping groups, allocating a time-frequency block including a hopping duration and a non-overlapped group, respectively, assigning a different set of orthogonal codes to each user, spreading data (or pilot) symbols of each user over the allocated time-frequency block, wherein the data (or pilot) symbols of each user are spread using the different set of orthogonal codes assigned to each user, mapping each data (or pilot) symbol to a modulation symbol in the time-frequency block, generating an orthogonal waveform based on the mapped symbols, and transmitting the orthogonal waveform.

Claims

1. A method for determining estimates of wireless transmissions received at a base station from a plurality of user devices, the wireless transmissions between the user devices and the base station occurring over a plurality of sub-carriers, the method comprising:

dividing the plurality of sub-carriers into a plurality of non-overlapping groups of sub-carriers;

assigning at least one user device to one non-overlapping group of one sub-carrier;

receiving transmissions from one user device, the user device configured to hop between frequencies over time within the one non-overlapping group of the one sub-carrier; and

estimating channels from consecutive sub-carriers within the one non-overlapping group using pilot symbols.

2. The method of claim 1, wherein the receiving comprises receiving transmissions from multiple user devices configured to hop between frequencies over time within multiple non-overlapping groups of multiple sub-carriers.

3. The method of claim 2, wherein the estimating channels comprises estimating channels from consecutive sub-carriers within multiple non-overlapping groups using common pilot symbols.

4. The method of claim 1, further comprising multiplexing across different user devices.

5. The method of claim 1, further comprising multiplexing across different signals from the one user device.

6. The method of claim 1, further comprising:

assigning each user device a different set of orthogonal codes;

wherein the one user device is configured to spread symbols between frequencies over time using one set of orthogonal codes.

7. The method of claim 3, wherein the dividing and estimating enables multiple user devices to share a single time-frequency allocation over the plurality of sub-carriers.

8. An apparatus configured to determine estimates of wireless transmissions received from a plurality of user devices over a plurality of sub-carriers, comprising:

a controller configured to divide the plurality of sub-carriers into a plurality of non-overlapping groups of sub-carriers and assign at least one user device to one non-overlapping group of one sub-carrier;

a receiver configured to receive transmissions from one user device, the user device configured to hop between frequencies over time within the one non-overlapping group of the one sub-carrier; and

a demodulator configured to estimate channels from consecutive sub-carriers within the one non-overlapping group using pilot symbols.

9. The apparatus of claim 8, wherein the receiver is configured to receive wireless transmissions from multiple user devices configured to hop between frequencies over time within multiple non-overlapping groups of multiple sub-carriers.

10. The apparatus of claim 9, wherein the demodulator estimates channels from consecutive sub-carriers within multiple non-overlapping groups using common pilot symbols.

11. The apparatus of claim 8, wherein the demodulator is configured to multiplex received signals across different user devices.

12. The apparatus of claim 8, wherein the demodulator is configured to multiplex across different signals from the one user device.

13. The apparatus of claim 8, wherein each user device is assigned a different set of orthogonal codes, the one user device is configured to spread symbols between frequencies over time using one set of orthogonal codes, and the demodulator is configured to estimate channels based on symbols received that have been spread using multiple sets of orthogonal codes.

14. The apparatus of claim 11, wherein the controller, receiver, and modulator collectively enable multiple user devices to share a single time-frequency allocation over the plurality of sub-carriers.

15. An apparatus configured to receive and estimate wireless transmissions from a plurality of user devices over a plurality of sub-carriers, comprising:

means for dividing the plurality of sub-carriers into a plurality of non-overlapping groups of sub-carriers;

means for assigning at least one user device to one non-overlapping group of one sub-carrier;

means for receiving transmissions from one user device, the user device configured to hop between frequencies over time within the one non-overlapping group of the one sub-carrier; and

means for estimating channels from consecutive sub-carriers within the one non-overlapping group using pilot symbols.

16. The apparatus of claim 15, wherein the means for receiving comprise means for receiving transmissions from multiple user devices configured to hop between frequencies over time within multiple non-overlapping groups of multiple sub-carriers.

17. The apparatus of claim 16, wherein the means for estimating channels comprises means for estimating channels from consecutive sub-carriers within multiple non-overlapping groups using common pilot symbols.

18. A memory unit comprising software configured to execute a method for determining estimates of wireless transmissions received at a base station from a plurality of user devices, the wireless transmissions between the user devices and the base station occurring over a plurality of sub-carriers, the method comprising:

dividing the plurality of sub-carriers into a plurality of non-overlapping groups of sub-carriers;

assigning at least one user device to one non-overlapping group of one sub-carrier;

receiving transmissions from one user device, the user device configured to hop between frequencies over time within the one non-overlapping group of the one sub-carrier; and

estimating channels from consecutive sub-carriers within the one non-overlapping group using pilot symbols.

19. The memory unit of claim 18, wherein the receiving comprises receiving transmissions from multiple user devices configured to hop between frequencies over time within multiple non-overlapping groups of multiple sub-carriers.

20. The memory unit of claim 19, wherein the estimating channels comprises estimating channels from consecutive sub-carriers within multiple non-overlapping groups using common pilot symbols.

21. An apparatus configured to determine estimates of wireless transmissions received from a plurality of user devices over a plurality of sub-carriers, comprising:

a receiver configured to receive the wireless transmissions and provide a stream of received chips;

a receive pilot processor configured to receive the stream of received chips and recover data chips derived from the wireless transmissions; and

a demodulator configured to receive and coherently demodulate data chips using channel response estimates to obtain recovered data symbols;

wherein the wireless transmissions comprise transmissions received from multiple user devices configured to hop between frequencies over time within multiple non-overlapping groups of multiple sub-carriers and further wherein the demodulator is configured to estimate channels from consecutive sub-carriers within multiple non-overlapping groups using pilot symbols.

22. The apparatus of claim 21, wherein the demodulator is configured to multiplex received signals across different user devices.

23. The apparatus of claim 21, wherein the demodulator is configured to multiplex across different signals from the one user device.

24. The apparatus of claim 21, wherein each user device is assigned a different set of orthogonal codes, and each user device is configured to spread symbols between frequencies over time using one set of orthogonal codes, and the demodulator is configured to estimate channels based on symbols received that have been spread using multiple sets of orthogonal codes.

25. The apparatus of claim 21, wherein the receiver, receive pilot processor, and modulator collectively enable multiple user devices to share a single time-frequency allocation over multiple sub-carriers.

26. A method for determining estimates of wireless transmissions received from a plurality of user devices over a plurality of sub-carriers, comprising:

receiving the wireless transmissions and provide a stream of received chips based on the wireless transmissions;

receiving the stream of received chips and recovering data chips derived from the wireless transmissions; and

coherently demodulating data chips using channel response estimates to obtain recovered data symbols;

wherein the wireless transmissions comprise transmissions received from multiple user devices configured to hop between frequencies over time within multiple non-overlapping groups of multiple sub-carriers and further wherein the coherently demodulating comprises estimating channels from consecutive sub-carriers within multiple non-overlapping groups using pilot symbols.

27. The method of claim 26, wherein coherently demodulating comprises multiplexing received signals across different user devices.

28. The method of claim 26, wherein coherently demodulating comprises multiplexing across different signals from the one user device.

29. The method of claim 26, wherein each user device is assigned a different set of orthogonal codes, and each user device is configured to spread symbols between frequencies over time using one set of orthogonal codes, and the coherently demodulating comprises estimating channels based on symbols received that have been spread using multiple sets of orthogonal codes.

30. The method of claim 26, wherein the receiving wireless transmissions, receiving the stream of received chips, and coherently demodulating collectively enable multiple user devices to share a single time-frequency allocation over multiple sub-carriers.

31. An apparatus configured to determine estimates of wireless transmissions received from a plurality of user devices over a plurality of sub-carriers, comprising:

means for receiving the wireless transmissions and provide a stream of received chips based on the wireless transmissions;

means for receiving the stream of received chips and recovering data chips derived from the wireless transmissions; and

means for coherently demodulating data chips using channel response estimates to obtain recovered data symbols;

wherein the wireless transmissions comprise transmissions received from multiple user devices configured to hop between frequencies over time within multiple non-overlapping groups of multiple sub-carriers and further wherein the coherently demodulating comprises estimating channels from consecutive sub-carriers within multiple non-overlapping groups using pilot symbols.

32. The apparatus of claim 31, wherein the means for coherently demodulating comprise means for multiplexing received signals across different user devices.

33. The apparatus of claim 31, wherein the means for coherently demodulating comprise means for multiplexing across different signals from the one user device.

34. The apparatus of claim 31, wherein each user device is assigned a different set of orthogonal codes, and each user device is configured to spread symbols between frequencies over time using one set of orthogonal codes, and the means for coherently demodulating comprises means for estimating channels based on symbols received that have been spread using multiple sets of orthogonal codes.

35. The apparatus of claim 31, wherein the means for receiving wireless transmissions, means for receiving the stream of received chips, and means for coherently modulating collectively enable multiple user devices to share a single time-frequency allocation over multiple sub-carriers.

36. A memory unit comprising software configured to execute a method for determining estimates of wireless transmissions received from a plurality of user devices over a plurality of sub-carriers, comprising:

receiving the wireless transmissions and provide a stream of received chips based on the wireless transmissions;

receiving the stream of received chips and recovering data chips derived from the wireless transmissions; and

coherently demodulating data chips using channel response estimates to obtain recovered data symbols;

wherein the wireless transmissions comprise transmissions received from multiple user devices configured to hop between frequencies over time within multiple non-overlapping groups of multiple sub-carriers and further wherein the coherently demodulating comprises estimating channels from consecutive sub-carriers within multiple non-overlapping groups using common pilot symbols.

37. The memory unit of claim 36, wherein coherently demodulating comprises multiplexing received signals across different user devices.

38. The memory unit of claim 36, wherein coherently demodulating comprises multiplexing across different signals from the one user device.

39. The memory unit of claim 36, wherein each user device is assigned a different set of orthogonal codes, and each user device is configured to spread symbols between frequencies over time using one set of orthogonal codes, and the coherently demodulating comprises estimating channels based on symbols received that have been spread using multiple sets of orthogonal codes.

40. The memory unit of claim 36, wherein the receiving wireless transmissions, receiving the stream of received chips, and coherently demodulating collectively enable multiple user devices to share a single time-frequency allocation over multiple sub-carriers.

41. A method for providing wireless transmissions from a user device over a plurality of sub-carriers, comprising:

utilizing, at the user device, an assigned non-overlapping group of sub-carriers over which the user device is to transmit; and

providing transmissions from the user device by frequency hopping over time within the one non-overlapping group of sub-carriers over which the user device transmits;

wherein said providing transmissions comprises providing pilot symbols from the user device over time within the one non-overlapping group over which the user device transmits for use in channel estimation.

42. The method of claim 41, wherein the providing transmissions comprises providing common pilot symbols from the user device over time within the one non-overlapping group over which the user device transmits for use in channel estimation.

43. The method of claim 41, further comprising:

utilizing, at the user device, a user device specific set of orthogonal codes;

wherein the providing transmissions further comprises spreading symbols between frequencies over time using the user device specific set of orthogonal codes.

44. A user device configured to provide wireless transmissions over a plurality of sub-carriers, comprising:

a controller configured to utilize an assigned non-overlapping group of sub-carriers over which the user device is to transmit; and

a transmitter configured to provide transmissions by frequency hopping over time within the one non-overlapping group of sub-carriers over which the user device transmits received from the controller;

wherein said transmitter provides pilot symbols over time within the one non-overlapping group over which the user device transmits for use in channel estimation.

45. The user device of claim 44, wherein the transmitter provides common pilot symbols from the user device over time within the one non-overlapping group over which the user device transmits for use in channel estimation.

46. The user device of claim 44, wherein the controller utilizes a user device specific set of orthogonal codes to produce signals for transmission, and wherein the controller spreads symbols between frequencies over time using the user device specific set of orthogonal codes.

47. A user device configured to provide wireless transmissions over a plurality of sub-carriers, comprising:

means for utilizing, at the user device, an assigned non-overlapping group of sub-carriers over which the user device is to transmit; and

means for providing transmissions from the user device by frequency hopping over time within the one non-overlapping group of sub-carriers over which the user device transmits;

wherein said means for providing transmissions comprise means for providing pilot symbols from the user device over time within the one non-overlapping group over which the user device transmits for use in channel estimation.

48. The user device of claim 47, wherein the means for providing transmissions comprises means for providing common pilot symbols from the user device over time within the one non-overlapping group over which the user device transmits for use in channel estimation.

49. The user device of claim 47, further comprising:

means for utilizing, at the user device, a user device specific set of orthogonal codes;

wherein the means for providing transmissions further comprises means for spreading symbols between frequencies over time using the user device specific set of orthogonal codes.

50. A memory unit comprising software configured to execute a method for providing wireless transmissions from a user device over a plurality of sub-carriers, the method comprising:

utilizing, at the user device, an assigned non-overlapping group of sub-carriers over which the user device is to transmit; and

providing transmissions from the user device by frequency hopping over time within the one non-overlapping group of sub-carriers over which the user device transmits;

wherein said providing transmissions comprise providing pilot symbols from the user device over time within the one non-overlapping group over which the user device transmits for use in channel estimation.

51. The memory unit of claim 50, wherein providing transmissions comprises providing common pilot symbols from the user device over time within the one non-overlapping group over which the user device transmits for use in channel estimation.

52. The memory unit of claim 50, further comprising:

utilizing, at the user device, a user device specific set of orthogonal codes;

wherein the providing transmissions further comprises spreading symbols between frequencies over time using the user device specific set of orthogonal codes.

53. A user device configured to provide wireless transmissions over a plurality of sub-carriers, comprising:

a controller configured to utilize an assigned non-overlapping group of sub-carriers over which the user device is to transmit, said non-overlapping group not overlapping with groups utilized by other user devices in a region wherein the user device transmits;

a modulator configured to process data symbols for frequency hopping and transmission over the assigned non-overlapping group of sub-carriers; and

a transmit processor configured to receive modulated symbols from the modulator and provide N transmit symbols for N sub-carriers; and

a transmitter configured to transmit the N transmit symbols over the N sub-carriers using frequency hopping.

54. The user device of claim 53, further comprising a transform unit configured to transform the N transmit symbols into the time domain.

55. The user device of claim 54, wherein the transform unit provides a number of transformed symbols, the user device further comprising a cyclic prefix generator configured to repeat a portion of each transform symbol to form a symbol comprising N plus a number of data chips being repeated.

56. The user device of claim 55, further comprising a transmit pilot processor configured to receive a stream of data chips and at least one pilot symbol and generate a narrowband pilot signal.

57. The user device of claim 53, wherein the user device is assigned a user device set of orthogonal codes, and the user device is further configured to spread symbols between frequencies over time using the user device set of orthogonal codes.

58. A method for providing, from a user device, wireless transmissions over a plurality of sub-carriers, comprising:

utilizing an assigned non-overlapping group of sub-carriers over which the user device is to transmit, said non-overlapping group not overlapping with groups utilized by other user devices in a region wherein the user device transmits;

processing data symbols for frequency hopping and transmission over the assigned non-overlapping group of sub-carriers; and

receiving modulated symbols and providing N transmit symbols for N sub-carriers; and

transmitting the N transmit symbols over the N sub-carriers using frequency hopping.

59. The method of claim 58, further comprising transforming the N transmit symbols into the time domain.

60. The method of claim 59, wherein the transforming the N transmit symbols provides a number of transformed symbols, the method further comprising repeating a portion of each transform symbol to form a symbol comprising N plus a number of data chips being repeated.

61. The method of claim 60, further comprising receiving a stream of data chips and at least one pilot symbol and generating a narrowband pilot signal.

62. The method of claim 58, wherein the user device is assigned a user device set of orthogonal codes, and the method further comprises spreading symbols between frequencies over time using the user device set of orthogonal codes.

63. A user device configured to provide wireless transmissions over a plurality of sub-carriers, comprising:

means for utilizing an assigned non-overlapping group of sub-carriers over which the user device is to transmit, said non-overlapping group not overlapping with groups utilized by other user devices in a region wherein the user device transmits;

means for processing data symbols for frequency hopping and transmission over the assigned non-overlapping group of sub-carriers; and

means for receiving modulated symbols and providing N transmit symbols for N sub-carriers; and

means for transmitting the N transmit symbols over the N sub-carriers using frequency hopping.

64. The user device of claim 63, further comprising means for transforming the N transmit symbols into the time domain.

65. The user device of claim 64, wherein the means for transforming the N transmit symbols provides a number of transformed symbols, the user device further comprising means for repeating a portion of each transform symbol to form a symbol comprising N plus a number of data chips being repeated.

66. The user device of claim 65, further comprising means for receiving a stream of data chips and at least one pilot symbol and generating a narrowband pilot signal.

67. The user device of claim 66, wherein the user device is assigned a user device set of orthogonal codes, and the user device further comprises means for spreading symbols between frequencies over time using the user device set of orthogonal codes.

68. A memory unit comprising software configured to execute a method for providing, from a user device, wireless transmissions over a plurality of sub-carriers, the method comprising:

utilizing an assigned non-overlapping group of sub-carriers over which the user device is to transmit, said non-overlapping group not overlapping with groups utilized by other user devices in a region wherein the user device transmits;

processing data symbols for frequency hopping and transmission over the assigned non-overlapping group of sub-carriers; and

receiving modulated symbols and providing N transmit symbols for N sub-carriers; and

transmitting the N transmit symbols over the N sub-carriers using frequency hopping.

69. The memory unit of claim 68, the method further comprising transforming the N transmit symbols into the time domain.

70. The memory unit of claim 69, wherein the transforming the N transmit symbols provides a number of transformed symbols, the method further comprising repeating a portion of each transform symbol to form a symbol comprising N plus a number of data chips being repeated.

71. The memory unit of claim 70, the method further comprising receiving a stream of data chips and at least one pilot symbol and generating a narrowband pilot signal.

72. The memory unit of claim 68, wherein the user device is assigned a user device set of orthogonal codes, and the method further comprises spreading symbols between frequencies over time using the user device set of orthogonal codes.