ADAPTIVE CODING AND MODULATION FLOW CONTROL AND TRAFFIC SHAPING SYSTEMS AND METHODS

• US 20100172234A1
• Filed: 02/16/2010
• Published: 07/08/2010
• Est. Priority Date: 10/28/2005
• Status: Abandoned Application

• Current Assignee: ViaSat Incorporated
• Original Assignee: ViaSat Incorporated
• Inventors: Thesling, William H.
• Application Number:
  US12/706,351
• Publication Number:
  US 20100172234A1
• Time in Patent Office: Days
• US Class Current: 370/206
• CPC Class Codes: H04B 7/18543 for adaptation of transmission parameters, e.g. power control for detecting or preventing errors in the information received H04L1/00
• CPC Class Codes: H04B 7/18582 Arrangements for data linking, i.e. for data framing, for error recovery, for multiple access
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0007 by modifying the frame length
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/0016 involving special memory structures, e.g. look-up tables
• CPC Class Codes: H04L 1/0021 in which the algorithm uses adaptive thresholds
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/0083 Formatting with frames or packets; Protocol or part of protocol for error control
• CPC Class Codes: H04L 2001/0093 Point-to-multipoint
• CPC Class Codes: H04L 27/0008 arrangements for allowing a transmitter or receiver to use more than one type of modulation negotiating modulation type for two-way transmission paths H04L5/1453
• CPC Class Codes: H04L 47/6215 Individual queue per QOS, rate or priority
• CPC Class Codes: H04L 5/023 Multiplexing of multicarrier modulation signals multicarrier modulation H04L27/2601
• CPC Class Codes: H04W 28/10 Flow control between communication endpoints
• CPC Class Codes: H04W 72/1221 based on age of data to be sent
• CPC Class Codes: H04W 72/542 using measured or perceived quality
• CPC Class Codes: H04W 80/00 Wireless network protocols or protocol adaptations to wireless operation
• CPC Class Codes: H04W 84/06 Airborne or Satellite Networks space-based or airborne stations H04B7/185

Abstract

A process is described to build physical layer frames with a modcode adapted to the signal quality of a destination terminal. Data packets assigned to the same modcode may be sent in the same frame, although packets associated with higher modcodes may be used to complete a frame before switching to the applicable higher modcode for construction of subsequent frames. After an interval, the order of progression is restarted with an out of order packet above a threshold age. Flow control filtering mechanisms and a variable reliability margin may be used to adapt dynamically to the current data traffic conditions.

Claims

1-25. -25. (canceled)

26. A method of implementing adaptive modulation and coding for a plurality of packets in a network, the method comprising:

assigning a different modcode to each of a plurality of signal quality ranges, wherein a first range of the plurality of signal quality ranges is associated with a first modcode, a second range of the plurality of signal quality ranges is associated with a second modcode, and a boundary between the first range and the second range substantially defines a transition between the first modcode and the second modcode;

monitoring a latency measurement associated with the network; and

dynamically adjusting, responsive to when the monitored latency measurement crosses a threshold, the boundary to modify a reliability margin for delivery of packets destined for a link in the network with a signal quality within the first or second range.

27. The method of claim 26, wherein the adjusting comprises:

increasing a minimum signal quality boundary for the second range when a latency measurement decreases across the threshold, to thereby increase the reliability margin for packets associated with the second modcode, wherein the minimum signal quality boundary comprises the boundary.

28. The method of claim 26, wherein the adjusting comprises:

decreasing a minimum signal quality boundary for the second range when a latency measurement increases across the threshold, to thereby decrease the reliability margin for packets associated with the second modcode, wherein the minimum signal quality boundary comprises the boundary.

29. The method of claim 26, wherein the method is performed by a gateway, and the network comprises a satellite communications network including the gateway.

30. The method of claim 29, further comprising:

receiving the latency measurement, the latency measurement performed by a device remote from the gateway within the satellite communications network.

31. The method of claim 26, further comprising:

measuring a delay at a gateway between an arrival timestamp and a transmission timestamp for a plurality of transmitted packets to produce the latency measurement.

32. The method of claim 26, wherein the latency measurement comprises a measurement of traffic load at a gateway.

33. The method of claim 26, wherein the latency measurement comprises a measurement of traffic load in a satellite communications network comprising the network.

34. The method of claim 26, wherein the latency measurement consists of latency statistics received from a plurality of devices comprising the network.

35. The method of claim 26, further comprising:

transmitting a subset of the plurality of packets according to a defined order of progression; and

interrupting the defined order of progression upon expiration of a timer to transmit an out of order packet of the plurality of packets, the out of order packet exceeding a threshold age.

36. The method of claim 35, further comprising:

modifying the period of the timer based at least in part on the latency measurement.

37. The method of claim 26, further comprising:

blocking additional packets when the latency measurement exceeds a second threshold.

38. The method of claim 26, further comprising:

allowing packets associated with a selected quality of service or class of service while blocking other packets when the latency measurement exceeds a second threshold.

39. The method of claim 26, wherein,

the adaptive coding and modulation is implemented in accordance with a digital video broadcasting—

satellite—

second generation specification;

the signal quality comprises at least one of a signal to noise ratio, an estimated signal to noise ratio, a bit error rate, a receive power level, and another communication link quality indicator; and

the reliability margin is greater than zero.

40. A device for implementing adaptive modulation and coding for a plurality of packets, the device comprising:

a processor configured to;

assign a different modcode to each of a plurality of signal quality ranges, wherein a first range of the plurality of signal quality ranges is associated with a first modcode, a second range of the plurality of signal quality ranges is associated with a second modcode, and a boundary between the first range and the second range substantially defines a transition between the first modcode and the second modcode;

monitor a latency measurement associated with a network; and

dynamically adjust, responsive to when the monitored latency measurement crosses a threshold, the boundary to modify a reliability margin for delivery of packets destined for a link within the first or second range; and

a transmitter, communicatively coupled with the processor and configured to;

transmit a subset of the plurality of packets destined for a link within the first or second range according to an assigned modcode.

41. The device of claim 40, wherein the processor is configured to perform the dynamic adjustment by:

increasing a minimum signal quality boundary for the second range when a latency measurement decreases across the threshold, to thereby increase the reliability margin for the second range, wherein the minimum signal quality boundary comprises the boundary.

42. The device of claim 41, wherein the processor is further configured to perform the dynamic adjustment by:

decreasing a minimum signal quality boundary for the second range when a latency measurement increases across the threshold, to thereby decrease the reliability margin for the second range, wherein the minimum signal quality boundary comprises the boundary.

43. The device of claim 40, wherein the device is a gateway, and the network comprises a satellite communications network including the gateway.

44. The device of claim 40, wherein the latency measurement is performed remotely from the device.

45. The device of claim 40, wherein the processor is further configured to:

measure a delay between an arrival timestamp at the device and a transmission timestamp at the device for each of a plurality of received packets to generate the latency measurement.

46. The device of claim 40, wherein the latency measurement comprises a measurement of an amount of data traffic waiting to be transmitted from the device.

47. The device of claim 40, wherein the latency measurement comprises a measurement of data traffic within a satellite communications network.

48. The device of claim 40, wherein the transmitter is further configured to:

transmit a subset of the plurality of packets according to a defined order of progression; and

interrupt the defined order of progression upon expiration of a timer to transmit an out of order packet of the plurality of packets, the out of order packet exceeding a threshold age.

49. The device of claim 48, wherein the transmitter is further configured to:

modify the period of the timer based at least in part on the latency measurement.

50. The device of claim 40, wherein the processor is further configured to:

block additional packets from being processed when the latency measurement exceeds a second threshold.

51. The device of claim 40, wherein the processor is further configured to:

allow packets associated with a selected quality of service or class of service to be processed, while blocking other packets when the latency measurement exceeds a second threshold.

52. A device for implementing adaptive modulation and coding for a plurality of packets in a satellite communications network, the method comprising:

means for assigning a different modcode to each of a plurality of signal quality ranges, wherein a first range of the plurality of signal quality ranges is associated with a first modcode, a second range of the plurality of signal quality ranges is associated with a second modcode, and a boundary between the first range and the second range substantially defines a transition between the first modcode and the second modcode;

means for monitoring a latency measurement associated with the satellite network; and

means for dynamically adjusting, responsive to when the monitored latency measurement crosses a threshold, the boundary to modify a reliability margin for delivery of packets destined for a link with a signal quality within the first or second range.

53. A satellite communications network for implementing adaptive modulation and coding for a plurality of packets in a satellite communications network, the network comprising:

a gateway configured to;

assign a different modcode to each of a plurality of signal quality ranges, wherein a first range of the plurality of signal quality ranges is associated with a first modcode, a second range of the plurality of signal quality ranges is associated with a second modcode, and a boundary between the first range and the second range substantially defines a transition between the first modcode and the second modcode;

monitor a latency measurement associated with the satellite network;

dynamically adjust, responsive to when the monitored latency measurement crosses a threshold, the boundary to modify a reliability margin for delivery of packets destined for a link within the first or second range; and

transmit a subset of the plurality of packets destined for a terminal with a link condition within the first or second range according to the assigned modcode; and

the terminal, in communication with the gateway via satellite, and configured to receive the transmitted subset according to the assigned modcode.

54. The satellite communications network of claim 53, wherein the gateway is further configured to:

receive a signal quality measurement from the terminal via satellite; and

assign the assigned modcode according to signal quality measurement.

55. The satellite communications network of claim 53, wherein the gateway is configured to perform the dynamic adjustment by:

increasing a minimum signal quality boundary for the second range when a latency measurement decreases across the threshold, to thereby increase the reliability margin for the second range; and

decreasing a minimum signal quality boundary for the second range when a latency measurement increases across the threshold, to thereby decrease the reliability margin for the second range, wherein the minimum signal quality boundary comprises the boundary.