Dynamic link assignment in a communication system

• US 7,706,315 B2
• Filed: 07/17/2009
• Issued: 04/27/2010
• Est. Priority Date: 07/24/2000
• Status: Expired due to Term

• Current Assignee: ViaSat Incorporated
• Original Assignee: ViaSat Incorporated
• Inventors: Thesling, William H., Vanderaar, Mark J., Nimon, Matthew D.
• Primary Examiner(s): Bost; Dwayne
• Assistant Examiner(s): Mehra; Inder P
• Application Number:
  US12/505,289
• Publication Number:
  US 20090279475A1
• Time in Patent Office: 284 Days
• Field of Search: 370315-316, 370/352, 370/401, 370/466, 370/469, 455/12.1, 455/69, 455/427
• US Class Current: 370/316
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/0025 Transmission of mode-switching indication
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 2001/0093 Point-to-multipoint
• CPC Class Codes: H04L 27/2601 Multicarrier modulation systems
• CPC Class Codes: H04L 27/2602 Signal structure
• CPC Class Codes: H04L 27/2657 Carrier synchronisation
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/003 Arrangements for allocating sub-channels of the transmission path
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals

Abstract

An architecture for the dynamic assignment of links in a multi-user communication system. A plurality of information channels are provided in a forward communication link of the communication system for carrying channel information of the plurality of information channels from a transmitter to a plurality of corresponding receiving devices. The channel information in corresponding select ones of the plurality of information channels is varied dynamically in response to link conditions of the associated receiving devices to more efficiently utilize the channel bandwidth.

Claims

1. A gateway for transmitting a packet via a satellite to a selected user terminal of a plurality of user terminals, the gateway comprising:

a receiver configured to receive a transmission signal, from the selected user terminal, including information identifying reception quality for the user terminal from the satellite;

one or more processor modules, communicatively coupled with the receiver, and configured to;

utilize the identified reception quality information to identify a modulation and coding format for the user terminal from a plurality of modulation and coding formats;

dynamically assign the modulation and coding format to the packet addressed to the selected user terminal; and

generate a frame to carry the packet to the selected user terminal via the satellite, wherein generating the frame comprises;

generating a frame header identifying a size associated with a payload portion of the frame, identifying the modulation and coding format, and identifying a start of frame location; and

encapsulating the packet addressed to the user terminal within the payload portion of the frame; and

a transmitter, communicatively coupled with the one or more processor modules, and configured to transmit the payload portion of the frame according to the dynamically assigned modulation and coding format addressed to the selected user terminal.

2. The gateway of claim 1, wherein the one or more processor modules are further configured to:

process information received from the user terminal indicating the reception quality for the user terminal has changed in excess of a threshold; and

changing the modulation and coding format for other packets destined for the user terminal to account for the changed reception quality.

3. The gateway of claim 1, wherein the transmitter is configured to transmit the payload portion of the frame in a time-division multiplexed signal.

4. The gateway of claim 1, wherein the payload portion of the frame further comprises a second packet destined for a second selected user terminal.

5. The gateway of claim 1, wherein the frame header comprises a synchronization slot, a frame definition slot, and a user header slot.

6. The gateway of claim 1, wherein the frame header comprises a synchronization slot identifying the start of frame location, a frame definition slot identifying the modulation and coding format, and a user header slot identifying the size associated with the payload portion of the frame.

7. The gateway of claim 1, wherein the frame header comprises a frame definition slot identifying the modulation and coding format for the packet and a user header slot identifying a size associated with the packet, the size associated with the packet comprising the size associated with the payload portion of the frame.

8. The gateway of claim 1, wherein the frame header comprises a plurality of time slots of the frame before the payload portion of the frame.

9. The gateway of claim 1, wherein the frame header comprises a first time slot identifying the modulation and coding format and a second time slot identifying the start of frame location, and the first time slot and the second time slot are not immediately adjacent in time.

10. The gateway of claim 9, wherein the frame header further comprises a third time slot identifying the size associated with the payload portion of the frame, and wherein the third time slot and the second time slot are not immediately adjacent in time and the third time slot and the first time slot are not immediately adjacent in time.

11. The gateway of claim 1, wherein the frame header comprises a unique word to identify the start of frame location.

12. A gateway for transmitting a packet via a satellite to a selected user terminal of a plurality of user terminals, the gateway comprising:

means for receiving a transmission signal, from the selected user terminal, including information identifying reception quality for the user terminal from the satellite;

means for utilizing the identified reception quality information to identify a modulation and coding format for the user terminal from a plurality of modulation and coding formats;

means for dynamically assigning the modulation and coding format to the packet addressed to the selected user terminal;

means for generating a frame to carry the packet to the selected user terminal via the satellite, wherein generating the frame comprises;

generating a frame header identifying a size associated with a payload portion of the frame, identifying a modulation and coding format, and identifying a start of frame location; and

encapsulating the packet addressed to the user terminal within the payload portion of the frame; and

means for transmitting the packet in the payload portion of the frame according to the dynamically assigned modulation and coding format addressed to the selected user terminal.

13. The gateway of claim 12, further comprising:

means for processing information received from the user terminal indicating the reception quality for the user terminal has changed; and

means for changing the modulation and coding format for other packets destined for the user terminal to account for the changed reception quality.

14. The gateway of claim 12, further comprising:

means for encapsulating, within the payload portion of the frame, a second packet destined for a second set of one or more selected user terminals.

15. The gateway of claim 12, wherein the frame header comprises a synchronization slot identifying the start of frame location, a frame definition slot identifying the modulation and coding format, and a user header slot identifying a size associated with the packet.

16. The gateway of claim 12, wherein the frame header comprises a plurality of time slots of the frame that are not immediately adjacent in time.

17. The gateway of claim 12, wherein the frame header comprises a first time slot identifying the modulation and coding format and a second time slot identifying a start of frame location, and the first time slot and the second time slot are not immediately adjacent in time.

18. The gateway of claim 17, wherein the frame header further comprises a third time slot identifying the size associated with the payload portion of the frame, and wherein the third time slot and the second time slot are not immediately adjacent in time and the third time slot and the first time slot are not immediately adjacent in time.

19. The gateway of claim 12, wherein the frame header comprises a unique word to identify the start of frame location.

20. A method for transmitting a packet via a satellite to a selected user terminal of a plurality of user terminals, the device comprising:

controlling a transmitter to transmit a first packet according to a first modulation and coding format addressed to the selected user terminal, the first modulation and coding format identified responsive to a reception quality at the user terminal;

receiving from the selected user terminal after the first packet is transmitted, a transmission signal including information identifying a changed reception quality for the user terminal from the satellite;

evaluating the changed reception quality information to identify a second modulation and coding format from a plurality of modulation and coding formats;

dynamically assigning the second modulation and coding format to a second packet;

generating a frame to carry the packet to the selected user terminal via the satellite, wherein generating the frame comprises;

generating a frame header identifying a size associated with a payload portion of the frame, identifying the second modulation and coding format, and identifying a start of frame location; and

encapsulating the second packet addressed to the user terminal within the payload portion of the frame; and

controlling the transmitter to transmit the payload portion of the frame according to the dynamically assigned second modulation and coding format addressed to the selected user terminal.

21. The method of claim 20, wherein the evaluating step comprises:

evaluating the changed reception quality information to determine that the changed reception quality exceeds a threshold, and thereby identify the second modulation and coding format as a higher order higher modulation and coding format associated with the changed reception quality.

22. The method of claim 20, wherein the payload portion of the frame is wirelessly transmitted in a time-division multiplexed signal.

23. The method of claim 20, further comprising:

encapsulating a second packet destined for a second selected user terminal within the payload portion of the frame.

24. The method of claim 20, wherein the frame header comprises a synchronization slot, a frame definition slot, and a user header slot.

25. The method of claim 20, wherein the frame header comprises a synchronization slot identifying the start of frame location, a frame definition slot identifying the second modulation and coding format, and a user header slot identifying the size associated with the payload portion of the frame, the size comprising a length of the second packet.

26. The method of claim 20, wherein the frame header comprises a frame definition slot identifying the second modulation and coding format and a user header slot identifying the size associated with the payload portion of the frame, the size comprising a length substantially comprising a length of the second packet.

27. The method of claim 20, wherein the frame header comprises a plurality of time slots of the frame, wherein a subset of the plurality of time slots is not immediately adjacent in time.

28. The method of claim 20, wherein the frame header comprises a first time slot identifying the second modulation and coding format and a second time slot identifying the start of frame location, and the first time slot and the second time slot are not immediately adjacent in time.

29. The method of claim 20, wherein the frame header further comprises a first time slot identifying the second modulation and coding format and a second time slot identifying the size associated with the payload portion of the frame, and the first time slot and the second time slot are not immediately adjacent in time.

30. The method of claim 20, wherein the frame header comprises a unique word to identify a start of frame location.

31. A device for transmitting a packet via a satellite to a selected user terminal of a plurality of user terminals, the device comprising:

a receiver configured to;

receive a first transmission signal, from the selected user terminal, including information identifying reception quality for the user terminal from the satellite, a first modulation and coding format identified responsive to a reception quality at the user terminal; and

receive a second transmission signal, from the selected user terminal, including information identifying a changed reception quality for the user terminal from the satellite;

one or more processor modules configured to;

evaluate the information from the second transmission signal to identify the changed reception quality;

identify a changed modulation and coding format from a plurality of modulation and coding formats, the changed modulation and coding format based on the changed reception quality;

dynamically adjust the modulation and coding format to be used for packets to be transmitted to the selected user to the changed modulation and coding format; and

generate a frame to carry the packet to the selected user terminal and carry additional packets to other user terminals via the satellite, wherein generating the frame comprises;

generating a frame header identifying a size associated with a payload portion of the frame, identifying the changed modulation and coding format, and identifying a start of frame location; and

encapsulating the packet addressed to the user terminal within the payload portion of the frame; and

a transmitter configured to transmit the frame payload, the frame comprising the frame header transmitted according to a protected modulation and coding format and the payload portion of the frame addressed to the selected user terminal according to the changed modulation and coding format.