Frequency hopping design for single carrier FDMA systems

• US 9,036,538 B2
• Filed: 08/22/2005
• Issued: 05/19/2015
• Est. Priority Date: 04/19/2005
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Palanki, Ravi
• Primary Examiner(s): Behnamian, Shahriar
• Application Number:
  US11/209,246
• Publication Number:
  US 20060233124A1
• Time in Patent Office: 3,557 Days
• Field of Search: 375/132, 375/260, 375/340, 370/347, 370/256, 370/319, 370/337, 370/480, 370/478, 370/329, 370/341, 455/450, 455/434
• US Class Current: 370/319
• CPC Class Codes: H04B 1/7143 Arrangements for generation of hop patterns
• CPC Class Codes: H04L 5/0044 allocation of payload

Abstract

Systems and methodologies are described that facilitate frequency hopping in a single carrier FDMA wireless environment by dynamically altering user offsets with time to obtain interference diversity. A channel tree can be utilized with nodes that are assigned values. User devices can be assigned to such nodes, a path between an assigned node and a root node in the channel tree can be evaluated, and a table lookup can be performed to determine an identity of a subcarrier set to assign to the user device assigned to a given node, as well as a number of subcarriers to be assigned to the user device. Additionally, node values can be dynamically varied during a communication event to alter path values and thus alter subcarrier set assignments.

Claims

1. A method of generating single-carrier frequency division multiple-access (FDMA) symbols, comprising:

obtaining a first subcarrier set assignment comprising a first set of contiguous subcarriers in a first time interval, the first set including a configurable number of subcarriers;

generating at least one single-carrier FDMA symbol for transmission on the first set of contiguous subcarriers in the first time interval;

obtaining a second subcarrier set assignment comprising a second set of contiguous subcarriers in a second time interval, the second set of contiguous subcarriers being varied from the first set of contiguous subcarriers according to a predetermined pattern, wherein a plurality of sets of contiguous subcarriers are flexibly defined in each time interval and assignable to different user devices; and

generating at least one other single carrier FDMA symbol for transmission on the second set of contiguous subcarriers in the second time interval.

2. The method of claim 1, wherein the first and second sets of subcarriers are associated with different offsets in a predetermined set of offsets.

3. The method of claim 1, wherein the predetermined pattern is delineated by transmission of a number of frames.

4. The method of claim 1, wherein the predetermined pattern is delineated by expiration of a time period.

5. The method of claim 1, wherein each of the first and second subcarrier set assignments is used for transmission of a predetermined number of single-carrier FDMA symbols.

6. The method of claim 1, wherein the obtaining the first subcarrier set assignment comprises

determining a channel tree including a plurality of nodes;

and

determining the first set of subcarriers based on a node in the channel tree assigned to a user device.

7. The method of claim 1, further comprising

employing an interleaved frequency division multiple-access (IFDMA) protocol to generate at least one additional single carrier FDMA symbol.

8. The method of claim 1, further comprising

determining the first set of subcarriers based on a channel tree comprising a plurality of nodes.

9. The method of claim 8, further comprising

reading a path in the channel tree from a user device-assigned node upward to a root node of the tree.

10. The method of claim 9, further comprising

assessing value of nodes in the path, beginning with the user device-assigned node and ending with a first child node of the root node.

11. The method of claim 10, further comprising

performing a table lookup to identify the first set of subcarriers corresponding to the value of the path from the user device-assigned node to the first child node of the root node.

12. The method of claim 8, wherein node value assignments are periodically varied to alter subcarrier set assignments.

13. The method of claim 8, wherein each node in the channel tree is assigned a non-binary value.

14. The method of claim 8, wherein each node in the channel tree is assigned a binary value.

15. The method of claim 1, further comprising

employing an interleaved frequency division multiple-access (IFDMA) protocol to generate one or more additional single-carrier FDMA symbols, and wherein subcarrier set assignments are varied upon transmission of each additional single-carrier FDMA symbol to enable channel estimation over an entire available bandwidth.

16. The method of claim 1, further comprising

employing a localized frequency division multiple-access (LFDMA) protocol to generate the at least one single carrier FDMA symbol.

17. The method of claim 1, wherein subcarrier set assignments are varied as a function of sector identity, or time, or both.

18. The method of claim 1, wherein the first and second sets of subcarriers are constrained to a portion of system bandwidth.

19. The method of claim 1, wherein the first and second sets include equal number of subcarriers determined based on an allocated subcarrier set size among a plurality of supported subcarrier set sizes.

20. The method of claim 2, wherein the offsets of the first and second sets of subcarriers are determined based on the number of subcarriers in the first and second sets of subcarriers.

21. An apparatus comprising:

means for obtaining a first subcarrier set assignment comprising a first set of contiguous subcarriers in a first time interval, the first set including a configurable number of subcarriers;

means for generating at least one single-carrier frequency division multiple-access (FDMA) symbol for transmission on the first set of contiguous subcarriers in the first time interval;

means for obtaining a second subcarrier set assignment comprising a second set of contiguous subcarriers in a second time interval, the second set of contiguous subcarriers being varied from the first set of contiguous subcarriers according to a predetermined pattern, wherein a plurality of sets of contiguous subcarriers are flexibly defined in each time interval and assignable to different user devices; and

means for generating at least one other single carrier FDMA symbol for transmission on the second set of contiguous subcarriers in the second time interval.

22. The apparatus of claim 21, the means for obtaining the first subcarrier set assignment comprises

means for determining the first set of subcarriers based on a node in a channel tree allocated to a user device.

23. The apparatus of claim 22, the means for determining the first set of subcarriers comprises

means for reading a path in the channel tree from the allocated user node to a root node to determine a value for nodes in the path that identifies the first set of subcarriers assigned to the user device and the number of subcarriers to include in the first set.

24. The apparatus of claim 23, the means for obtaining the second subcarrier set assignment comprises means for altering values assigned to one or more nodes in the channel tree to vary the value of the path between the allocated user node and the root node.

25. The apparatus of claim 24, the means for obtaining the second subcarrier set assignment comprises means for determining the second set of subcarriers associated with the varied value of the path from the allocated user node to the root node.

26. The apparatus of claim 25, wherein node values are altered upon transmission of the at least one single carrier FDMA symbol.

27. The apparatus of claim 21, further comprising

means for employing an interleaved frequency division multiple-access (IFDMA) protocol to generate one or more additional single-carrier FDMA symbols, and wherein subcarrier set assignments are varied upon transmission of each additional single-carrier FDMA symbol to enable channel estimation over an entire available bandwidth.

28. The apparatus of claim 21, further comprising

means for employing a localized frequency division multiple-access (LFDMA) protocol to generate the at least one single carrier FDMA symbol.

29. A method of generating single-carrier frequency division multiple-access (FDMA) symbols, comprising:

obtaining a first subcarrier set assignment comprising a first set of contiguous subcarriers in a first time interval, the first set including a configurable number of subcarriers;

generating at least one single-carrier FDMA symbol at a user device for transmission on the first set of contiguous subcarriers in the first time interval;

obtaining a second subcarrier set assignment comprising a second set of contiguous subcarriers in a second time interval, the second set of contiguous subcarriers being varied from the first set of contiguous subcarriers according to a predetermined pattern, wherein a plurality of sets of contiguous subcarriers are flexibly defined in each time interval and assignable to different user devices; and

generating at least one other single carrier FDMA symbol at the user device for transmission on the second set of contiguous subcarriers in the second time interval.

30. The method of claim 29, wherein the obtaining the first subcarrier set assignment comprises

determining a channel tree including a plurality of nodes;

and

determining the first set of subcarriers based on a node in the channel tree assigned to the user device.

31. The method of claim 29, wherein the predetermined pattern is delineated by transmission of a number of frames.

32. The method of claim 29, wherein the predetermined pattern is delineated by expiration of a time period.

33. The method of claim 29, wherein each of the first and second subcarrier set assignments is used for transmission of a predetermined number of single-carrier FDMA symbols.

34. An apparatus for wireless communication, comprising:

at least one processor configured to obtain a first subcarrier set assignment comprising a first set of contiguous subcarriers in a first time interval, the first set including a configurable number of subcarriers, to generate at least one single-carrier frequency division multiple-access (FDMA) symbol for transmission on the first set of contiguous subcarriers in the first time interval, to obtain a second subcarrier set assignment comprising a second set of contiguous subcarriers in a second time interval, the second set of contiguous subcarriers being varied from the first set of contiguous subcarriers according to a predetermined pattern, wherein a plurality of sets of contiguous subcarriers are flexibly defined in each time interval and assignable to different user devices, and to generate at least one other single-carrier FDMA symbol for transmission on the second set of contiguous subcarriers in the second time interval.

35. The apparatus of claim 34, wherein the at least one processor is configured to use each of the first and second subcarrier set assignments for transmission of a predetermined number of single-carrier FDMA symbols.

36. The apparatus of claim 34, wherein the at least one processor is configured to determine a channel tree including a plurality of nodes, and to determine the first set of subcarriers based on a node in the channel tree assigned to a user device.

37. The apparatus of claim 34, wherein the first and second sets include equal number of subcarriers determined based on an allocated subcarrier set size among a plurality of supported subcarrier set sizes.

38. The apparatus of claim 34, wherein the first and second sets of subcarriers are constrained to a portion of system bandwidth.

39. The apparatus of claim 34, wherein the at least one processor is configured to generate one or more additional single-carrier FDMA symbols based on an interleaved frequency division multiple-access (IFDMA) protocol.

40. The apparatus of claim 34, wherein the at least one processor is configured to generate single-carrier FDMA symbols based on a localized frequency division multiple-access (LFDMA) protocol.

41. A non-transitory computer program medium encoded with a computer program, comprising:

code for causing at least one computer to obtain a first subcarrier set assignment comprising a first set of contiguous subcarriers in a first time interval, the first set including a configurable number of subcarriers,

code for causing the at least one computer to generate at least one single-carrier frequency division multiple-access (FDMA) symbol for transmission on the first set of contiguous subcarriers in the first time interval,

code for causing the at least one computer to obtain a second subcarrier set assignment comprising a second set of contiguous subcarriers in a second time interval, the second set of contiguous subcarriers being varied from the first set of contiguous subcarriers according to a predetermined pattern, wherein a plurality of sets of contiguous subcarriers are flexibly defined in each time interval and assignable to different user devices, and

code for causing the at least one computer to generate at least one other single-carrier FDMA symbol for transmission on the second set of contiguous subcarriers in the second time interval.

42. A method of receiving single-carrier frequency division multiple-access (FDMA) symbols, comprising:

determining a first subcarrier set assignment comprising a first set of contiguous subcarriers in a first time interval, the first set including a configurable number of subcarriers;

receiving at least one single-carrier FDMA symbol on the first set of contiguous subcarriers in the first time interval;

determining a second subcarrier set assignment comprising a second set of contiguous subcarriers in a second time interval, the second set of contiguous subcarriers being varied from the first set of contiguous subcarriers according to a predetermined pattern, wherein a plurality of sets of contiguous subcarriers are flexibly defined in each time interval and assignable to different user devices; and

receiving at least one other single-carrier FDMA symbol on the second set of contiguous subcarriers in the second time interval.

43. The method of claim 42, further comprising:

selecting a subcarrier set size among a plurality of supported subcarrier set sizes to allocate to a user device, wherein the first and second sets include equal number of subcarriers determined by the selected subcarrier set size.

44. The method of claim 42, wherein each of the first and second subcarrier set assignments is valid for a predetermined number of single-carrier FDMA symbols.

45. The method of claim 42, wherein the first and second sets of subcarriers are associated with different offsets in a predetermined set of offsets, each offset being associated with a different starting subcarrier.

46. The method of claim 45, wherein the offsets of the first and second sets of subcarriers are determined based on the number of subcarriers in the first and second sets of subcarriers.

47. The method of claim 42, wherein the first and second sets of subcarriers are determined based on a channel tree including a plurality of nodes, each node being associated with a different set of subcarriers.

48. The method of claim 47, further comprising:

assigning a node in the channel tree to a user device, wherein the first and second sets of subcarriers are determined based on the assigned node.

49. The method of claim 47, wherein the plurality of nodes in the channel tree are associated with at least two different subcarrier set sizes.

50. The method of claim 47, wherein the plurality of nodes in the channel tree are associated with equal subcarrier set size.

51. The method of claim 47, wherein nodes in the channel tree associated with equal subcarrier set size are further associated with different offsets.

52. The method of claim 47, wherein each node in the channel tree is associated with a unique combination of subcarrier set size and offset for the set of subcarriers associated with the node.

53. The method of claim 47, wherein the channel tree comprises multiple tiers, and wherein nodes in each tier are associated with different non-overlapping sets of subcarriers having different offsets.

54. The method of claim 42, further comprising:

varying subcarrier set assignments as a function of sector identity, or time, or both.

55. The method of claim 42, further comprising:

processing at least one additional single-carrier FDMA symbol in accordance with an interleaved frequency division multiple-access (IFDMA) protocol.

56. The method of claim 42, further comprising:

processing the at least one single-carrier FDMA symbol in accordance with a localized frequency division multiple-access (LFDMA) protocol.

57. An apparatus for wireless communication, comprising:

means for determining a first subcarrier set assignment comprising a first set of contiguous subcarriers in a first time interval, the first set including a configurable number of subcarriers;

means for receiving at least one single-carrier frequency division multiple-access (FDMA) symbol on the first set of contiguous subcarriers in the first time interval;

means for determining a second subcarrier set assignment comprising a second set of contiguous subcarriers in a second time interval, the second set of contiguous subcarriers being varied from the first set of contiguous subcarriers according to a predetermined pattern, wherein a plurality of sets of contiguous subcarriers are flexibly defined in each time interval and assignable to different user devices; and

means for receiving at least one other single-carrier FDMA symbol on the second set of contiguous subcarriers in the second time interval.

58. The apparatus of claim 57, further comprising:

means for selecting a subcarrier set size among a plurality of supported subcarrier set sizes to allocate to a user device, wherein the first and second sets include equal number of subcarriers determined by the selected subcarrier set size.

59. The apparatus of claim 57, further comprising:

means for assigning a user device to a node in a channel tree, wherein the first and second sets of subcarriers are determined based on the assigned node.

60. An apparatus for wireless communication, comprising:

at least one processor configured to determine a first subcarrier set assignment comprising a first set of contiguous subcarriers in a first time interval, the first set including a configurable number of subcarriers, to receive at least one single-carrier frequency division multiple-access (FDMA) symbol on the first set of contiguous subcarriers in the first time interval, to determine a second subcarrier set assignment comprising a second set of contiguous subcarriers in a second time interval, the second set of contiguous subcarriers being varied from the first set of contiguous subcarriers according to a predetermined pattern, wherein a plurality of sets of contiguous subcarriers are flexibly defined in each time interval and assignable to different user devices, and to receive at least one other single-carrier FDMA symbol on the second set of contiguous subcarriers in the second time interval.

61. The apparatus of claim 60, wherein the at least one processor is configured to select a subcarrier set size among a plurality of supported subcarrier set sizes to allocate to a user device, and wherein the first and second sets include equal number of subcarriers determined by the selected subcarrier set size.

62. The apparatus of claim 60, wherein the at least one processor is configured to assign a user device to a node in a channel tree, and wherein the first and second sets of subcarriers are determined based on the assigned node.

63. A non-transitory computer program medium encoded with a computer program, comprising:

code for causing at least one computer to determine a first subcarrier set assignment comprising a first set of contiguous subcarriers, the first set including a configurable number of subcarriers in a first time interval,

code for causing the at least one computer to receive at least one single-carrier frequency division multiple-access (FDMA) symbol on the first set of contiguous subcarriers in the first time interval,

code for causing the at least one computer to determine a second subcarrier set assignment comprising a second set of contiguous subcarriers in a second time interval, the second set of contiguous subcarriers being varied from the first set of contiguous subcarriers according to a predetermined pattern, wherein a plurality of sets of contiguous subcarriers are flexibly defined in each time interval and assignable to different user devices, and

code for causing the at least one computer to receive at least one other single-carrier FDMA symbol on the second set of contiguous subcarriers in the second time interval.

64. A method of generating single-carrier frequency division multiple-access (FDMA) symbols, comprising:

obtaining an assignment of a set of subcarriers in a first time interval, the set including a configurable number of subcarriers, wherein a plurality of sets of subcarriers are flexibly defined in the first time interval and assignable to different user devices;

mapping pilot symbols to the set of subcarriers; and

generating at least one single-carrier FDMA symbol with the pilot symbols mapped to the set of subcarriers.

65. The method of claim 64, further comprising:

obtaining a second assignment of a second set of subcarriers in a second time interval, the second set of subcarriers being varied from the first set of subcarriers according to a predetermined pattern;

mapping pilot symbols to the second set of subcarriers; and

generating at least one other single-carrier FDMA symbol with the pilot symbols mapped to the second set of subcarriers.

66. The method of claim 64, wherein the set of subcarriers includes contiguous subcarriers.

67. The method of claim 64, wherein the set of subcarriers includes evenly-spaced subcarriers.

68. The method of claim 67, wherein the plurality of sets of subcarriers are assigned to a plurality of user devices for pilot transmission, the plurality of sets of subcarriers being interlaced.

69. The method of claim 64, wherein the set of subcarriers is determined based on a channel tree.

70. An apparatus for wireless communication, comprising:

means for obtaining an assignment of a set of subcarriers in a first time interval, the set including a configurable number of subcarriers, wherein a plurality of sets of subcarriers are flexibly defined in the first time interval and assignable to different user devices;

means for mapping pilot symbols to the set of subcarriers; and

means for generating at least one single-carrier frequency division multiple-access (FDMA) symbol with the pilot symbols mapped to the set of subcarriers.

71. The apparatus of claim 70, further comprising:

means for obtaining a second assignment of a second set of subcarriers in a second time interval, the second set of subcarriers being varied from the first set of subcarriers according to a predetermined pattern;

means for mapping pilot symbols to the second set of subcarriers; and

means for generating at least one other single-carrier FDMA symbol with the pilot symbols mapped to the second set of subcarriers.

72. The apparatus of claim 70, wherein the set of subcarriers includes contiguous subcarriers.

73. The apparatus of claim 70, wherein the set of subcarriers includes evenly-spaced subcarriers.

74. The apparatus of claim 73, wherein the plurality of sets of subcarriers are assigned to a plurality of user devices for pilot transmission, the plurality of sets of subcarriers being interlaced.

75. The apparatus of claim 70, wherein the set of subcarriers is determined based on a channel tree.

76. An apparatus for wireless communication, comprising:

at least one processor configured to obtain an assignment of a set of subcarriers in a first time interval, the set including a configurable number of subcarriers, wherein a plurality of sets of subcarriers are flexibly defined in the first time interval and assignable to different user devices, to map pilot symbols to the set of subcarriers, and to generate at least one single-carrier frequency division multiple-access (FDMA) symbol with the pilot symbols mapped to the set of subcarriers.

77. The apparatus of claim 76, wherein the at least one processor is configured to obtain a second assignment of a second set of subcarriers in a second time interval, the second set of subcarriers being varied from the first set of subcarriers according to a predetermined pattern, to map pilot symbols to the second set of subcarriers, and to generate at least one other single-carrier FDMA symbol with the pilot symbols mapped to the second set of subcarriers.

78. The apparatus of claim 76, wherein the set of subcarriers includes contiguous subcarriers.

79. The apparatus of claim 76, wherein the set of subcarriers includes evenly-spaced subcarriers.

80. The apparatus of claim 79, wherein the plurality of sets of subcarriers are assigned to a plurality of user devices for pilot transmission, the plurality of sets of subcarriers being interlaced.

81. The apparatus of claim 76, wherein the set of subcarriers is determined based on a channel tree.

82. A non-transitory computer program medium encoded with a computer program, comprising:

code for causing at least one computer to obtain an assignment of a set of subcarriers in a first time interval, the set including a configurable number of subcarriers, wherein a plurality of sets of subcarriers are flexibly defined in the first time interval and assignable to different user devices,

code for causing the at least one computer to map pilot symbols to the set of subcarriers, and

code for causing the at least one computer to generate at least one single-carrier frequency division multiple-access (FDMA) symbol with the pilot symbols mapped to the set of subcarriers.