Wireless communication system with enhanced time slot allocation and interference avoidance/mitigation features and related methods

• US 20040028018A1
• Filed: 03/27/2003
• Published: 02/12/2004
• Est. Priority Date: 01/10/2002
• Status: Active Grant

• Current Assignee: Stingray IP Solutions LLC (Acacia Research Corporation)
• Original Assignee: Harris Corporation (L3Harris Technologies, Inc.)
• Inventors: Cain, Joseph Bibb
• Granted Patent: US 6,958,986 B2
• Time in Patent Office: Days
• US Class Current: 370/338
• CPC Class Codes: H04B 7/18506 Communications with or from aircraft, i.e. aeronautical mobile service
• CPC Class Codes: H04B 7/2643 using time-division multiple access [TDMA] H04B7/2615, H04B7/2618 take precedence
• CPC Class Codes: H04L 1/0041 Arrangements at the transmitter end
• CPC Class Codes: H04L 1/0061 Error detection codes
• CPC Class Codes: H04L 1/203 Details of error rate determination, e.g. BER, FER or WER
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 72/542 using measured or perceived quality
• CPC Class Codes: H04W 72/56 based on priority criteria
• CPC Class Codes: H04W 72/569 of the traffic information
• CPC Class Codes: H04W 74/04 Scheduled access hybrid access H04W74/02
• CPC Class Codes: H04W 76/10 Connection setup
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks

Abstract

A wireless communication network may include a plurality of mobile nodes each including a wireless transceiver and a controller for controlling the wireless transceiver. The controller may also be for scheduling a respective semi-permanent time slot to establish a communication link with neighboring mobile nodes for transmitting data therebetween, where the data has different priority levels. The controller may also determine respective link utilization metrics for each data priority level for each communication link, and schedule demand assigned time slots for establishing additional communication links with the neighboring mobile nodes for transmitting data therebetween based upon the link utilization metrics and data priority levels. The wireless communication network may also provide enhanced interference avoidance and/or mitigation features in certain embodiments.

Claims

1. A wireless communication network comprising:

a plurality of mobile nodes each comprising a wireless transceiver and a controller for controlling said wireless transceiver, said controller also for

scheduling a respective semi-permanent time slot to establish a communication link with neighboring mobile nodes for transmitting data therebetween, the data having different priority levels,

determining respective link utilization metrics for each data priority level for each communication link, and

scheduling demand assigned time slots for establishing additional communication links with the neighboring mobile nodes for transmitting data therebetween based upon the link utilization metrics and data priority levels.

2. The wireless communication network of claim 1 wherein said controller determines link utilization metrics for each data priority level for each additional communication link, and re-allocates the demand assigned time slots based upon the link utilization metrics for each data priority level for each additional communication link and the data priority levels.

3. The wireless communication network of claim 2 wherein said controller re-allocates the demand assigned time slots by:

designating demand assigned time slots to be re-allocated based upon the respective link utilization metrics associated therewith;

estimating reduced capacity link utilization metrics between mobile nodes for each data priority level based upon losing respective designated demand assigned time slots assigned thereto; and

re-allocating the designated demand assigned time slots based upon the estimated reduced capacity link utilization metrics.

4. The wireless communication network of claim 2 wherein said controller re-allocates the demand assigned time slot by:

designating demand assigned time slots to be re-allocated based upon the respective link utilization metrics associated therewith;

estimating increased capacity link utilization metrics between mobile nodes for each data priority level based upon gaining respective designated demand assigned time slots assigned thereto; and

re-allocating the designated demand assigned time slots based upon the estimated increased capacity link utilization metrics.

5. The wireless communication network of claim 1 wherein each link utilization metric is determined based upon a quantity of data sent during at least one prior semi-permanent time slot corresponding to the respective priority level.

6. The wireless communication network of claim 1 wherein said controller further comprises a queue for storing data prior to transmitting, and wherein each link utilization metric is determined based upon a quantity of data corresponding to the respective priority level in said queue.

7. The wireless communication network of claim 1 wherein said controller determines an aggregate link metric for each communication link based upon a weighted sum of the link utilization metrics for each communication link.

8. The wireless communication network of claim 1 wherein the communication link and additional communication links comprise directional communication links;

and wherein each node further comprises a phased array antenna connected to said wireless transceiver and controlled by said controller.

9. A wireless communication network comprising:

a plurality of mobile nodes each comprising a wireless transceiver and a controller for controlling said wireless transceiver, said controller comprising a data queue and also for

scheduling respective semi-permanent time slots to establish communication links with neighboring mobile nodes for transmitting data stored in said data queues therebetween,

determining link utilization metrics for each communication link based upon a quantity of data previously sent over the communication link during the semi-permanent time slots and the data queue, and

scheduling demand assigned time slots for establishing additional communication links with said neighboring mobile nodes for transmitting the data based upon the link utilization metrics.

10. The wireless communication network of claim 9 wherein the data has different priority levels;

wherein said controller also determines respective link utilization metrics for each data priority level for each communication link, and schedules demand assigned time slots further based upon the link utilization metrics and data priority levels.

11. The wireless communication network of claim 10 wherein said controller determines link utilization metrics for each data priority level for each additional communication link and re-allocates the demand assigned time slots based thereon.

12. The wireless communication network of claim 11 wherein said controller re-allocates the demand assigned time slots by:

designating demand assigned time slots to be re-allocated based upon the respective link utilization metrics associated therewith;

estimating reduced capacity link utilization metrics between mobile nodes for each data priority level based upon losing respective designated demand assigned time slots assigned thereto; and

re-allocating the designated demand assigned time slots based upon the estimated reduced capacity link utilization metrics.

13. The wireless communication network of claim 11 wherein said controller re-allocates the demand assigned time slot by:

designating demand assigned time slots to be re-allocated based upon the respective link utilization metrics associated therewith;

estimating increased capacity link utilization metrics between mobile nodes for each data priority level based upon gaining respective designated demand assigned time slots assigned thereto; and

re-allocating the designated demand assigned time slots based upon the estimated increased capacity link utilization metrics.

14. The wireless communication network of claim 10 wherein each link utilization metric is determined based upon a quantity of data sent during at least one prior semi-permanent time slot corresponding to the respective priority level.

15. The wireless communication network of claim 10 wherein said controller determines an aggregate link metric for each communication link based upon a weighted sum of the link utilization metrics for each communication link.

16. The wireless communication network of claim 9 wherein the communication link and additional communication links comprise directional communication links;

and wherein each node further comprises a phased array antenna connected to said wireless transceiver and controlled by said controller.

17. A wireless communication network comprising:

a plurality of mobile nodes each comprising a wireless transceiver and a controller for controlling said wireless transceiver, said controller also for scheduling a directional communication link to a neighboring mobile node during a time slot by

determining relative positions of the neighboring mobile node and other potentially interfering mobile nodes transmitting during the time slot,

determining potential interference to the directional communication link based upon the relative positions, and

scheduling the directional communication link during the time slot if the potential interference is below a threshold.

18. The wireless communication network of claim 17 wherein said controller determines the relative positions based upon a respective distance and angle to the neighboring mobile node and each potentially interfering mobile node.

19. The wireless communication network of claim 17 wherein said controller determines the relative positions based upon a plane-earth attenuation algorithm.

20. The wireless communication network of claim 17 wherein said controller determines the relative positions based upon a free space attenuation algorithm.

21. The wireless communication network of claim 17 wherein said controller determines the potential interference based upon estimated signal path loss.

22. The wireless communication network of claim 17 wherein said controller determines the potential interference based upon side lobes from signals transmitted by the potentially interfering nodes and a side lobe suppression algorithm.

23. The wireless communication network of claim 17 wherein said controller receives a request from said neighboring mobile node to establish the directional communication link prior to determining the relative positions.

24. The wireless communication network of claim 17 wherein said controller after scheduling the directional communication link intermittently determines relative positions of the neighboring mobile node and other potentially interfering nodes, determines potential interference to the directional communication link based upon the intermittently determined relative positions, and schedules the directional communication link during a new time slot if the potential interference rises above the threshold.

25. The wireless communication network of claim 17 wherein said controller has a look up table for storing signal-to-interference values, and wherein said controller further determines the interference based upon the stored signal-to-interference values.

26. The wireless communication network of claim 17 wherein said mobile nodes further comprise a position determining device for measuring a respective position thereof;

and wherein said controller determines the relative positions based upon the measured positions of said neighboring mobile node and said potentially interfering mobile nodes.

27. A wireless communication network comprising:

a plurality of mobile nodes establishing communication links therebetween during assigned time slots and re-allocating the assigned time slots based upon usage requirements;

an initiating mobile node identifying available time slots shared with neighboring mobile nodes, ranking the available time slots based upon link utilization during the time slots by said initiating mobile node and said neighboring mobile nodes, and transmitting a time slot re-allocation request to a receiving mobile node including the available time slots and ranking thereof;

said receiving mobile node receiving the time slot re-allocation request, ranking the available time slots based upon link utilization during the available time slots by said receiving mobile node and mobile nodes neighboring said receiving mobile node, generating a combined ranking of the available time slots based upon the rankings thereof by said initiating mobile node and said receiving mobile node, and re-allocating at least one of the available time slots for establishing a communication link between said initiating mobile node and said receiving mobile node based upon the combined ranking.

28. The wireless communication network of claim 27 wherein said initiating mobile node and said receiving mobile node each determines a traffic demand metric associated with each available time slot and removes from consideration for re-allocation any available time slot having a traffic demand metric associated therewith above a high usage threshold.

29. The wireless communication network of claim 27 wherein said initiating mobile node and said receiving mobile node each determines a signal-to-interference (SIR) value associated with each available time slot and removes from consideration for re-allocation any available time slots having an SIR value associated therewith above a high SIR threshold.

30. The wireless communication network of claim 27 wherein said initiating mobile node and said receiving mobile node each determines a signal-to-interference (SIR) value associated with each available time slot and further ranks the time slots based thereon.

31. The wireless communication network of claim 27 wherein said initiating mobile node and said receiving mobile node transmit data having a plurality of priority levels;

and wherein said receiving mobile node only re-allocates an available time slot if data to be transmitted during the available time slot has an equal or greater priority level than data currently being transmitted during the available time slot.

32. The wireless communication network of claim 27 wherein said initiating mobile node and said receiving mobile node each estimates a reduced capacity link utilization metric for each available time slot and further ranks the available time slots based thereon.

33. The wireless communication network of claim 27 wherein said initiating mobile node and said receiving mobile node each ranks the available time slots based upon an average quantity of data transmitted therein.

34. The wireless communication network of claim 27 wherein said mobile nodes comprise queues for storing data to be transmitted over the communication links;

and wherein said initiating mobile node and said receiving mobile node each ranks the available time slots based upon their respective queues.

35. The wireless communication network of claim 27 wherein said mobile nodes each comprise a wireless transceiver, an antenna connected to said wireless transceiver, and a controller for controlling said wireless transceiver.

36. A wireless communication network comprising:

a plurality of mobile nodes each comprising a wireless transceiver and a controller for controlling said wireless transceiver;

a pair of said mobile nodes establishing a communication link for transmitting packets therebetween during at least one time slot, at least one of said mobile nodes from said pair of mobile nodes determining a link quality value associated with the communication link during the at least one time slot and determining if the communication link is of a first or second quality;

said pair of mobile nodes cooperating to re-allocate the communication link to a new time slot within a first time period if the communication link is of the first quality during the at least one time slot, and cooperating to re-allocate the communication link to a new time slot within a second time period shorter than the first time period if the communication link is of the second quality during the at least one time slot.

37. The wireless communication network of claim 36 wherein said at least one mobile node from said pair of mobile nodes determines the link quality value based upon at least one of a signal-to-interference ratio (SIR) and a packet reception error value (PREV).

38. The wireless communication network of claim 37 wherein the communication link is determined to be of the first quality if the SIR is between a first SIR threshold and a second SIR threshold higher than the first SIR threshold, and the PREV is between a first error threshold and a second error threshold higher than the first error threshold.

39. The wireless communication network of claim 38 wherein the communication link is also determined to be of the first quality if the SIR is less than the first SIR threshold and the PREV is greater than the second error threshold.

40. The wireless communication network of claim 38 wherein the communication link is determined to be of the second quality if the SIR is less than the first SIR threshold and the PREV is between the first error threshold and the second error threshold.

41. The wireless communication network of claim 38 wherein the communication link is determined to be of the second quality if the PREV is below the first error threshold.

42. The wireless communication network of claim 36 wherein the at least one time slot comprises at least one demand assigned time slot;

and wherein said pair of mobile nodes also establish an additional communication link during a semi-permanent time slot.

43. The wireless communication network of claim 42 wherein at least one of said mobile nodes from said pair of mobile nodes determines a semi-permanent link quality value associated with the additional communication link during the semi-permanent time slot and also determines if the additional communication link is of the first or second quality during the semi-permanent time slot based upon the semi-permanent link quality value;

and wherein said pair of mobile nodes cooperate to re-allocate the additional communication link to a new semi-permanent time slot within the second period if the additional communication link is of the first or second quality during the semi-permanent time slot.

44. The wireless communication network of claim 36 wherein said mobile nodes further comprise a directional antenna connected to said wireless transceiver and controlled by said controller;

and wherein the communication link comprises a directional communication link.

45. The wireless communication network of claim 44 wherein said plurality of mobile nodes further comprise an omni-directional antenna connected to said wireless transceiver;

wherein said pair of mobile nodes cooperate to establish an omni-directional communication link therebetween; and

wherein said pair of mobile nodes also substantially immediately de-allocate the at least one time slot if the communication link is of the second quality and an omni-directional quality,value associated with the omni-directional communication link falls below an omni-directional quality threshold for a predetermined period.

46. A communication method for a wireless communication network comprising a plurality of mobile nodes, the method comprising:

scheduling a respective semi-permanent time slot to establish communication links between respective pairs of mobile nodes for transmitting data therebetween, the data having different priority levels;

determining respective link utilization metrics for each data priority level for each communication link; and

scheduling demand assigned time slots for establishing additional communication links between the pairs of mobile nodes for transmitting data therebetween based upon the link utilization metrics and data priority levels.

47. The method of claim 46 wherein determining comprises determining link utilization metrics for each data priority level for each additional communication link;

and further comprising re-allocating the demand assigned time slots based upon the link utilization metrics for each data priority level for each additional communication link and the data priority levels.

48. The method of claim 47 wherein re-allocating further comprises:

designating demand assigned time slots to be re-allocated based upon the respective link utilization metrics associated therewith;

estimating reduced capacity link utilization metrics between respective pairs of mobile nodes for each data priority level based upon losing respective designated demand assigned time slots assigned thereto; and

re-allocating the designated demand assigned time slots based upon the estimated reduced capacity link utilization metrics.

49. The method of claim 47 wherein re-allocating further comprises:

designating demand assigned time slots to be re-allocated based upon the respective link utilization metrics associated therewith;

estimating increased capacity link utilization metrics between respective pairs of mobile nodes for each data priority level based upon gaining respective designated demand assigned time slots assigned thereto; and

re-allocating the designated demand assigned time slots based upon the estimated increased capacity link utilization metrics.

50. The method of claim 46 wherein determining comprises determining each link utilization metric based upon a quantity of data sent during at least one prior semi-permanent time slot corresponding to the respective priority level.

51. The method of claim 46 wherein each mobile node comprises a queue for storing data prior to transmitting, and wherein the link utilization metrics are determined based upon quantities of data in the queues corresponding to respective priority levels.

52. The method of claim 46 wherein determining comprises determining an aggregate link metric for each communication link based upon a weighted sum of the link utilization metrics for each communication link.

53. The method of claim 46 wherein the communication link and additional communication links comprise directional communication links.

54. A communication method for a wireless communication network comprising a plurality of mobile nodes each comprising a data queue, the method comprising:

scheduling respective semi-permanent time slots to establish communication links between respective pairs of mobile nodes for transmitting data stored in the data queues therebetween;

determining link utilization metrics for each communication link based upon a quantity of data previously sent over the communication link during the semi-permanent time slots and the data queues; and

scheduling demand assigned time slots for establishing additional communication links between the pairs of mobile nodes for transmitting the data based upon the link utilization metrics.

55. The method of claim 54 wherein the data has different priority levels;

wherein determining further comprises determining respective link utilization metrics for each data priority level for each communication link; and

wherein scheduling further comprises scheduling demand assigned time slots based upon the link utilization metrics and data priority levels.

56. The method of claim 55 further comprising determining link utilization metrics for each data priority level for each additional communication link and re-allocating the demand assigned time slots based thereon.

57. The method of claim 56 wherein re-allocating comprises:

designating demand assigned time slots to be re-allocated based upon the respective link utilization metrics associated therewith;

estimating reduced capacity link utilization metrics between respective pairs of mobile nodes for each data priority level based upon losing respective designated demand assigned time slots assigned thereto; and

re-allocating the designated demand assigned time slots based upon the estimated reduced capacity link utilization metrics.

58. The method of claim 56 wherein re-allocating comprises:

designating demand assigned time slots to be re-allocated based upon the respective link utilization metrics associated therewith;

estimating increased capacity link utilization metrics between respective pairs of mobile nodes for each data priority level based upon gaining respective designated demand assigned time slots assigned thereto; and

re-allocating the designated demand assigned time slots based upon the estimated increased capacity link utilization metrics.

59. The method of claim 55 wherein determining comprises determining each link utilization metric based upon a quantity of data sent during at least one prior semi-permanent time slot corresponding to the respective priority level.

60. The method of claim 55 wherein determining comprises determining an aggregate link metric for each communication link based upon a weighted sum of the link utilization metrics for each communication link.

61. The method of claim 54 wherein the communication link and additional communication links comprise directional communication links.

62. A communication method for a wireless communication network comprising a plurality of mobile nodes, the method comprising:

scheduling a directional communication link from a first mobile node to a second neighboring mobile node during a time slot by

determining relative positions of the second neighboring mobile node and other potentially interfering mobile nodes transmitting during the time slot,

determining potential interference to the directional communication link based upon the relative positions, and

scheduling the directional communication link during the time slot if the potential interference is below a threshold.

63. The method of claim 62 wherein determining the relative positions comprises determining the relative positions based upon a respective distance and angle to the second neighboring mobile node and each potentially interfering mobile node.

64. The method of claim 62 wherein determining the relative positions comprises determining the relative positions based upon a plane-earth attenuation algorithm.

65. The method of claim 62 wherein determining the relative positions comprises determining the relative positions based upon a free space attenuation algorithm.

66. The method of claim 62 wherein determining the potential interference comprises determining the potential interference based upon estimated signal path loss.

67. The method of claim 62 wherein determining the potential interference comprises determining the potential interference based upon side lobes from signals transmitted by the potentially interfering nodes and a side lobe suppression algorithm.

68. The method of claim 62 wherein determining the relative position comprises determining the relative position responsive to a request from the second neighboring mobile node to establish the directional communication link.

69. The method of claim 62 further comprising, after scheduling the directional communication link:

intermittently determining relative positions of the second neighboring mobile node and other potentially interfering nodes;

determining potential interference to the directional communication link based upon the intermittently determined relative positions; and

scheduling the directional communication link during a new time slot if the potential interference rises above the threshold.

70. The method of claim 62 wherein the mobile nodes further comprise look-up tables for storing signal-to-interference (SIR) values, and wherein determining the potential interference comprises determining the potential interference based upon the stored SIR values.

71. The method of claim 62 wherein the mobile nodes further comprise a position determining device for measuring a respective position thereof;

and wherein determining the relative positions comprises determining the relative positions based upon the measured positions of the neighboring mobile node and the potentially interfering mobile nodes.

72. A method for establishing communication links between an initiating mobile node and a receiving mobile node in a wireless communication network comprising a plurality of mobile nodes, the method comprising:

identifying available time slots shared between the initiating mobile node and neighboring mobile nodes;

ranking the available time slots based upon link utilization during the time slots by the initiating mobile node and the neighboring mobile nodes;

transmitting a time slot re-allocation request from the initiating mobile node to the receiving mobile node including the available time slots and ranking thereof;

receiving the time slot re-allocation request at the receiving mobile node;

ranking the available time slots based upon link utilization during the available time slots by the receiving mobile node and mobile nodes neighboring the receiving mobile node;

generating a combined ranking of the available time slots based upon the rankings thereof by the initiating mobile node and the receiving mobile node; and

re-allocating at least one of the available time slots for establishing a communication link between the initiating mobile node and the receiving mobile node based upon the combined ranking.

73. The method of claim 72 wherein the initiating mobile node and the receiving mobile node each determines a traffic demand metric associated with each available time slot and removes from consideration for re-allocation any available time slot having a traffic demand metric associated therewith above a high usage threshold.

74. The method of claim 72 wherein the initiating mobile node and the receiving mobile node each determines a signal-to-interference (SIR) value associated with each available time slot and removes from consideration for re-allocation any available time slots having an SIR value associated therewith above a high SIR threshold.

75. The method of claim 72 wherein the initiating mobile node and the receiving mobile node each determines a signal-to-interference (SIR) value associated with each available time slot and further ranks the time slots based thereon.

76. The method of claim 72 wherein the initiating mobile node and the receiving mobile node transmit data having a plurality of priority levels;

and wherein re-allocating comprises re-allocating an available time slot only if data to be transmitted during the available time slot has an equal or greater priority level than data currently being transmitted during the available time slot.

77. The method of claim 72 wherein the initiating mobile node and the receiving mobile node each estimates a reduced capacity link utilization metric for each available time slot and further ranks the available time slots based thereon.

78. The method of claim 72 wherein the initiating mobile node and the receiving mobile node each ranks the available time slots based upon an average quantity of data transmitted therein.

79. The method of claim 72 wherein the mobile nodes comprise queues for storing data to be transmitted over the communication links;

and wherein the initiating mobile node and the receiving mobile node each ranks the available time slots based upon their respective queues.

80. A communication method for a wireless communication network comprising a plurality of mobile nodes, the method comprising:

establishing a communication link between a pair of the mobile nodes for transmitting packets therebetween during at least one time slot;

determining a link quality value associated L with the communication link during the at least one time slot and determining if the communication link is of a first or second quality;

re-allocating the communication link to a new time slot within a first time period if the communication link is of the first quality during the at least one time slot; and

re-allocating the communication link to a new time slot within a second time period shorter than the first time period if the communication link is of the second quality during the at least one time slot.

81. The method of claim 80 wherein determining comprises determining the link quality value based upon at least one of a signal-to-interference ratio (SIR) and a packet reception error value (PREV).

82. The method of claim 81 wherein the communication link is determined to be of the first quality if the SIR is between a first SIR threshold and a second SIR threshold higher than the first SIR threshold, and the PREV is between a first error threshold and a second error threshold higher than the first error threshold.

83. The method of claim 82 wherein the communication link is also determined to be of the first quality if the SIR is less than the first SIR threshold and the PREV is greater than the second error threshold.

84. The method of claim 83 wherein the communication link is determined to be of the second quality if the SIR is less than the first SIR threshold and the PREV is between the first error threshold and the second error threshold.

85. The method of claim 83 wherein the communication link is determined to be of the second quality if the PREV is below the first error threshold.

86. The method of claim 80 wherein the at least one time slot comprises at least one demand assigned time slot;

and further comprising establishing an additional communication link between the pair of mobile nodes during a semi-permanent time slot.

87. The method of claim 86 further comprising:

determining a semi-permanent link quality value associated with the additional communication link during the semi-permanent time slot;

determining if the additional communication link is of the first or second quality during the semi-permanent time slot based upon the semi-permanent link quality value; and

re-allocating the additional communication link to a new semi-permanent time slot within the second period if the additional communication link is of the first or second quality during the semi-permanent time slot.

88. The method of claim 80 wherein the communication link comprises a directional communication link.

89. The method of claim 88 further comprising:

establishing an omni-directional communication link between the pair of mobile nodes; and

substantially immediately de-allocating the at least one time slot if the communication link is of the second quality and an omni-directional quality value associated with the omni-directional communication link falls below an omni-directional quality threshold for a predetermined period.