Conveying sector load information to mobile stations

• US 20050201331A1
• Filed: 12/07/2004
• Published: 09/15/2005
• Est. Priority Date: 12/11/2003
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Ho, Sai Yiu Duncan, Gaal, Peter
• Granted Patent: US 7,751,367 B2
• Time in Patent Office: Days
• US Class Current: 370/332
• CPC Class Codes: H04B 7/024 Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems
• CPC Class Codes: H04W 16/24 Cell structures
• CPC Class Codes: H04W 36/0058 Transmission of hand-off measurement information, e.g. measurement reports
• CPC Class Codes: H04W 36/18 for allowing seamless reselection, e.g. soft reselection
• CPC Class Codes: H04W 36/20 for optimising the interference level
• CPC Class Codes: H04W 36/22 for handling the traffic
• CPC Class Codes: H04W 36/30 by measured or perceived connection quality data
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal

Abstract

Improved serving sector selection mechanisms are provided which convey sector load information to a wireless communicator. The wireless communicator can use carrier-to-interference (C/I) ratio measurements and sector load information for each of its Active Set (AS) sectors (or all sectors in its Active Set (AS)) to determine the best serving sector.

Claims

1. A system, comprising:

a plurality of remote stations each comprising a plurality of sectors, wherein each remote station comprises;

a processor which determines sector load information; and

a transmitter which transmits the sector load information; and

a wireless communicator, served by a current serving sector, comprising;

a channel quality estimator which measures the carrier-to-interference (C/I) ratio for each sector in the wireless communicator'"'"'s Active Set (AS);

a memory which stores the carrier-to-interference (C/I) ratio measurements for the sectors in the wireless communicator'"'"'s Active Set (AS); and

a processor which determines a new serving sector based on the carrier-to-interference (C/I) ratio measurements and the sector load information for each of the AS sectors.

2. A system according to claim 1,

wherein each sector has a plurality of neighbor sectors, and

wherein the current serving sector transmits the sector load information for all neighbor sectors to the wireless communicator.

3. A system according to claim 1, wherein the sector load information comprises a load information message comprising PN_OFFSET field which includes PN_OFFSET values and an PN_LOAD field which includes corresponding load value information.

4. A system according to claim 3, wherein the sector load information is included in an Channel Assignment Message (CAM)

5. A system according to claim 3, wherein the sector load information is included in a Handoff Direction Message (HDM),

6. A system according to claim 1, wherein the remote stations transmit the sector load information using a dedicated channel

7. A system according to claim 6, wherein the dedicated channel is a forward link channel transmitted to a single wireless communicator.

8. A system according to claim 1, wherein the dedicated channel is a forward packet data channel (F-PDCH)

9. A system according to claim 1, wherein the remote stations multicast the sector load information using a common channel

10. A system according to claim 9, wherein the common channel is a forward link channel transmitted to all wireless communicator'"'"'s served by the sector.

11. A system according to claim 10, wherein the common channel is a forward packet data channel (F-PDCH), wherein a single F-PDCH message carries load information for more than one sector.

12. A system according to claim 10, wherein the dedicated channel is a forward packet data control channel (F-PDCCH).

13. A system according to claim 1, wherein the sector load information comprises a load information broadcast message comprising PN_OFFSET field which includes PN_OFFSET values and an PN_LOAD field which includes corresponding load value information.

14. A system according to claim 13, wherein the load information broadcast message further comprises a MAC_ID field and a WALSH_MASK field.

15. A system according to claim 14, wherein if the MAC_ID has a first value, the remote station includes the WALSH_MASK field in the load information broadcast message and omits other fields

16. A system according to claim 14, wherein if the MAC_ID has a second value, the remote station includes the PN_OFFSET and PN_LOAD fields in the load information broadcast message.

17. A system according to claim 14, wherein if the MAC_ID has a third value, the remote station includes the PN_OFFSET and PN_LOAD fields in the load information broadcast message transmitted on the F-PDCH.

18. A system according to claim 14, wherein if the MAC_ID has another value, the remote station includes other remaining fields and omits the WALSH_MASK field, PN_OFFSET field and PN_LOAD filed in the load information broadcast message.

19. A system according to claim 14, wherein the other remaining fields comprise an EP_SIZE field, an ACID field, a SPID field, an AI_SN field, a LWCI field, EXT_MSG_TYPE field, and a RESERVED field.

20. A system according to claim 1, wherein the sector load information comprises a load information broadcast message comprising PN_OFFSET field which includes PN_OFFSET values and an PN_LOAD field which includes corresponding load value information, and wherein the wireless communicator stores the PN_LOAD value if the value of PN_OFFSET matches any of the AS sector pilots.

21. A system according to claim 20, wherein the wireless communicator, upon determining the new serving sector, modifies the measured the carrier-to-interference (C/I) ratio value to be used in the new serving sector selection, based on the corresponding value of PN_LOAD.

22. A system according to claim 20, wherein the wireless communicator, upon determining the new serving sector, adds the corresponding value of PN_LOAD to the measured the carrier-to-interference (C/I) ratio value.

23. A system according to claim 1, wherein each sector transmits a load value corresponding to its sector load information.

24. A remote station comprising a plurality of sectors, comprising:

a processor which determines sector load information; and

a transmitter which transmits the sector load information.

25. A remote station according to claim 24, wherein each sector has a plurality of neighbor sectors, and wherein a current serving sector transmits the sector load information for all neighbor sectors.

26. A remote station according to claim 24, wherein the sector load information comprises a load information message comprising PN_OFFSET field which includes PN_OFFSET values and an PN_LOAD field which includes corresponding load value information.

27. A remote station according to claim 26, wherein the sector load information is included in an Channel Assignment Message (CAM).

28. A remote station according to claim 26, wherein the sector load information is included in a Handoff Direction Message (HDM).

29. A remote station according to claim 24, wherein the remote station transmits the sector load information using a dedicated channel.

30. A remote station according to claim 29, wherein the dedicated channel is a forward link channel transmitted to a single wireless communicator.

31. A remote station according to claim 24, wherein the dedicated channel is a forward packet data channel (F-PDCH).

32. A remote station according to claim 24, wherein the remote stations multicast the sector load information using a common channel

33. A remote station according to claim 32, wherein the common channel is a forward link channel transmitted to all wireless communicator'"'"'s served by the sector.

34. A remote station according to claim 33, wherein the common channel is a forward packet data channel (F-PDCH), wherein a single F-PDCH message carries load information for more than one sector.

35. A remote station according to claim 33, wherein the dedicated channel is a forward packet data control channel (F-PDCCH).

36. A remote station according to claim 24, wherein the sector load information comprises a load information broadcast message comprising PN_OFFSET field which includes PN_OFFSET values and an PN_LOAD field which includes corresponding load value information.

37. A remote station according to claim 36, wherein the load information broadcast message further comprises a MAC_ID field and a WALSH_MASK field.

38. A remote station according to claim 37, wherein if the MAC_ID has a first value, the remote station includes the WALSH_MASK field in the load information broadcast message and omits other fields

39. A remote station according to claim 37, wherein if the MAC_ID has a second value, the remote station includes the PN_OFFSET and PN_LOAD fields in the load information broadcast message.

40. A remote station according to claim 37, wherein if the MAC_ID has a third value, the remote station includes the PN_OFFSET and PN_LOAD fields in the load information broadcast message transmitted on the F-PDCH.

41. A remote station according to claim 37, wherein if the MAC_ID has another value, the remote station includes other remaining fields and omits the WALSH_MASK field, PN_OFFSET field and PN_LOAD filed in the load information broadcast message.

42. A remote station according to claim 37, wherein the other remaining fields comprise an EP_SIZE field, an ACID field, a SPID field, an AI_SN field, a LWCI field, EXT_MSG_TYPE field, and a RESERVED field.

43. A remote station according to claim 24, wherein each sector transmits a load value corresponding to its sector load information.

44. A wireless communicator, served by a current serving sector, comprising:

a receiver which receives sector load information for each sector in the wireless communicator'"'"'s Active Set (AS);

a channel quality estimator which measures the carrier-to-interference (C/I) ratio for each sector in the wireless communicator'"'"'s Active Set (AS);

a memory which stores the carrier-to-interference (C/I) ratio measurements for the sectors in the wireless communicator'"'"'s Active Set (AS); and

a processor which determines a new serving sector based on the carrier-to-interference (C/I) ratio measurements and sector load information for each of the AS sectors.

45. A wireless communicator according to claim 44,

wherein each sector has a plurality of neighbor sectors, and

wherein the current serving sector transmits the sector load information for all neighbor sectors to the wireless communicator.

46. A wireless communicator according to claim 44, wherein the sector load information comprises a load information message comprising PN_OFFSET field which includes PN_OFFSET values and an PN_LOAD field which includes corresponding load value information.

47. A wireless communicator according to claim 46, wherein the sector load information is included in an Channel Assignment Message (CAM)

48. A wireless communicator according to claim 46, wherein the sector load information is included in a Handoff Direction Message (HDM),

49. A wireless communicator according to claim 44, wherein the sector load information is received over a dedicated channel

50. A wireless communicator according to claim 49, wherein the dedicated channel is a forward link channel transmitted only to the wireless communicator.

51. A wireless communicator according to claim 44, wherein the dedicated channel is a forward packet data channel (F-PDCH)

52. A wireless communicator according to claim 44, wherein the sector load information is received over a common channel.

53. A wireless communicator according to claim 52, wherein the common channel is a forward link channel transmitted to more than one wireless communicator served by the sector.

54. A wireless communicator according to claim 53, wherein the common channel is a forward packet data channel (F-PDCH), wherein a single F-PDCH message carries load information for more than one sector.

55. A wireless communicator according to claim 53, wherein the dedicated channel is a forward packet data control channel (F-PDCCH).

56. A wireless communicator according to claim 44, wherein the sector load information comprises a load information broadcast message comprising PN_OFFSET field which includes PN_OFFSET values and an PN_LOAD field which includes corresponding load value information.

57. A wireless communicator according to claim 56, wherein the load information broadcast message further comprises a MAC_ID field and a WALSH_MASK field.

58. A wireless communicator according to claim 57, wherein if the MAC_ID has a first value, the load information broadcast message includes the WALSH_MASK field an no other fields

59. A wireless communicator according to claim 57, wherein if the MAC_ID has a second value, the load information broadcast message includes the PN_OFFSET and PN_LOAD fields.

60. A wireless communicator according to claim 57, wherein if the MAC_ID has a third value, the load information broadcast message includes the PN_OFFSET and PN_LOAD fields and is received over the F-PDCH.

61. A wireless communicator according to claim 57, wherein if the MAC_ID has another value, the load information broadcast message includes other remaining fields and does not include the WALSH_MASK field, PN_OFFSET field and PN_LOAD filed.

62. A wireless communicator according to claim 57, wherein the other remaining fields comprise an EP_SIZE field, an ACID field, a SPID field, an AI_SN field, a LWCI field, EXT_MSG_TYPE field, and a RESERVED field.

63. A wireless communicator according to claim 44, wherein the sector load information comprises a load information broadcast message comprising PN_OFFSET field which includes PN_OFFSET values and a PN_LOAD field which includes corresponding load value information, and wherein the memory stores the PN_LOAD value if the processor determines which the value of PN_OFFSET matches any of the AS sector pilots.

64. A wireless communicator according to claim 63, wherein the processor, upon determining the new serving sector, modifies the measured the carrier-to-interference (C/I) ratio value to be used in the new serving sector selection, based on the corresponding value of PN_LOAD.

65. A wireless communicator according to claim 63, wherein the processor, upon determining the new serving sector, adds the corresponding value of PN_LOAD to the measured the carrier-to-interference (C/I) ratio value.

66. A wireless communicator according to claim 44, wherein each sector transmits a load value corresponding to its sector load information.

67. A method, comprising:

determining sector load information for a plurality of sectors comprising a current serving sector;

transmitting the sector load information; and

measuring the carrier-to-interference (C/I) ratio for each sector in an Active Set (AS);

storing the carrier-to-interference (C/I) ratio measurements for the sectors in the Active Set (AS); and

determining a new serving sector based on the carrier-to-interference (C/I) ratio measurements and the sector load information for each of the AS sectors.

68. A method according to claim 67,

wherein each sector has a plurality of neighbor sectors, and

wherein the current serving sector transmits the sector load information for all neighbor sectors.

69. A method according to claim 67, wherein the sector load information comprises a load information message comprising PN_OFFSET field which includes PN_OFFSET values and an PN_LOAD field which includes corresponding load value information.

70. A method according to claim 67, wherein the sector load information is transmitted on a dedicated channel.

71. A method according to claim 67, wherein the dedicated channel is a forward packet data channel (F-PDCH)

72. A method according to claim 67, wherein the sector load information is multicast on a common channel

73. A method according to claim 67, wherein the sector load information comprises a load information broadcast message comprising PN_OFFSET field which includes PN_OFFSET values and an PN_LOAD field which includes corresponding load value information.

74. A method according to claim 67, wherein the sector load information comprises a load information broadcast message comprising PN_OFFSET field which includes PN_OFFSET values and PN_LOAD field which includes corresponding load value information, and wherein the PN_LOAD value is stored if the value of PN_OFFSET matches any of the AS sector pilots.

75. A method according to claim 74, wherein upon determining the new serving sector:

modifying measured the carrier-to-interference (C/I) ratio value to be used in the new serving sector selection, based on the corresponding value of PN_LOAD.

76. A method according to claim 67, wherein each sector transmits a load value corresponding to its sector load information.

77. A method comprising:

determining sector load information; and

transmitting the sector load information.

78. A method according to claim 77, wherein each sector has a plurality of neighbor sectors, and wherein a current serving sector transmits the sector load information for all neighbor sectors.

79. A method according to claim 77, wherein the sector load information comprises a load information message comprising PN_OFFSET field which includes PN_OFFSET values and an PN_LOAD field which includes corresponding load value information.

80. A method according to claim 77, wherein the remote station transmits the sector load information using a dedicated channel.

81. A method according to claim 77, wherein the dedicated channel is a forward packet data channel (F-PDCH).

82. A method according to claim 77, wherein the remote stations multicast the sector load information using a common channel

83. A method according to claim 77, wherein the sector load information comprises a load information broadcast message comprising PN_OFFSET field which includes PN_OFFSET values and an PN_LOAD field which includes corresponding load value information.

84. A method according to claim 77, wherein each sector transmits a load value corresponding to its sector load information.

85. A method for use with a wireless communicator being served by a current serving sector, comprising:

receiving sector load information for each sector in the wireless communicator'"'"'s Active Set (AS);

measuring the carrier-to-interference (C/I) ratio for each sector in the wireless communicator'"'"'s Active Set (AS);

storing the carrier-to-interference (C/I) ratio measurements for the sectors in the wireless communicator'"'"'s Active Set (AS); and

determining a new serving sector based on the carrier-to-interference (C/I) ratio measurements and sector load information for each of the AS sectors.

86. A method according to claim 85,

wherein each sector has a plurality of neighbor sectors, and

wherein the current serving sector transmits the sector load information for all neighbor sectors to the wireless communicator.

87. A method according to claim 85, wherein the sector load information comprises a load information message comprising PN_OFFSET field which includes PN_OFFSET values and an PN_LOAD field which includes corresponding load value information.

88. A method according to claim 85, wherein the sector load information is received over a dedicated channel

89. A method according to claim 85, wherein the dedicated channel is a forward packet data channel (F-PDCH)

90. A method according to claim 85, wherein the sector load information is received over a common channel.

91. A method according to claim 85, wherein the sector load information comprises a load information broadcast message comprising PN_OFFSET field which includes PN_OFFSET values and an PN_LOAD field which includes corresponding load value information.

92. A method according to claim 85, wherein the sector load information comprises a load information broadcast message comprising PN_OFFSET field which includes PN_OFFSET values and a PN_LOAD field which includes corresponding load value information, and wherein the memory stores the PN_LOAD value if the processor determines which the value of PN_OFFSET matches any of the AS sector pilots.

93. A method according to claim 92, wherein the processor, upon determining the new serving sector, modifies the measured the carrier-to-interference (C/I) ratio value to be used in the new serving sector selection, based on the corresponding value of PN_LOAD.

94. A method according to claim 85, wherein each sector transmits a load value corresponding to its sector load information.