Downstream waveform modification

• US 8,208,421 B2
• Filed: 07/16/2008
• Issued: 06/26/2012
• Est. Priority Date: 10/03/2006
• Status: Active Grant

• Current Assignee: ViaSat Incorporated
• Original Assignee: ViaSat Incorporated
• Inventors: Dankberg, Mark D., Thesling, William H.
• Primary Examiner(s): Phillips, Hassan
• Assistant Examiner(s): Sharma, Gautam
• Application Number:
  US12/174,173
• Publication Number:
  US 20090022085A1
• Time in Patent Office: 1,441 Days
• Field of Search: None
• US Class Current: 370/316
• CPC Class Codes: H04B 7/18582 Arrangements for data linking, i.e. for data framing, for error recovery, for multiple access

Abstract

Systems, devices, processors, and methods are described for the transmission and reception of broadband signals between a gateway and subscriber terminals via satellite. In one set of embodiments, a wireless signal is generated and transmitted including a series of frames including a physical layer header and payload. A sub-channel identifier may be included in the physical layer header to identify the sub-channel for the payload, and allow for various novel filtering techniques at the subscriber terminal. The frames may be generated to be of substantially equal duration. Novel subscriber terminal configurations are described to leverage this formatting.

Claims

1. A gateway configured to transmit a signal to respective user terminals via a bent-pipe satellite, the gateway comprising:

a receiver configured to;

receive first data to be transmitted via the bent-pipe satellite destined for a first user terminal; and

receive second data identifying link conditions for the first user terminal;

a bandwidth allocator, communicatively coupled with the receiver, and configured to;

determine an increased bandwidth requirement for the first user terminal;

increase a proportional allocation of physical layer frames including a sub-channel identifier associated with the first user terminal; and

control an encapsulator to generate the physical layer frames with the sub-channel identifier in the increased proportion;

an adaptive coding and modulation assignor, communicatively coupled with the receiver, and configured to assign a modulation and coding format for the first data responsive to the link conditions;

the encapsulator, communicatively coupled with the receiver, the bandwidth allocator, and the adaptive coding and modulation assignor, and configured to;

utilize the assigned modulation and coding format to set a block size for a payload for a first physical layer frame, the block size set to produce a physical layer frame of substantially equal duration in reference to adjacent physical layer frames to be transmitted from the gateway; and

encapsulate at least a portion of the first data in the set block size for the payload of the first physical layer frame, the first physical layer frame including a header with the sub-channel identifier formatted to direct the first physical layer frame to the first user terminal and to provide information allowing the first user terminal to identify the first physical layer frame as a frame to be demodulated and decoded; and

a transmitter, communicatively coupled with the encapsulator, and configured to upconvert and transmit the first physical layer frame to the bent-pipe satellite.

2. The gateway of claim 1,

wherein the bandwidth allocator is further configured to vary the bandwidth for the respective user terminals via assignment of the sub-channel identifier.

3. The gateway of claim 1, further comprising:

a memory configured to store a table associating each of a plurality of different modulation and coding formats with respective block sizes, wherein the encapsulator queries the memory to identify the block size.

4. The gateway of claim 1, wherein the encapsulator is further configured to generate a header identifier to allow the first user terminal to identify one or more boundaries of the payload for the first physical layer frame.

5. The gateway of claim 1, wherein the sub-channel identifier is formatted to provide information allowing the first user terminal to identify a location for a next header identifier detection analysis in a set of physical layer frames received after the first physical layer frame.

6. The gateway of claim 1, wherein the header includes information on spacing between a plurality of additional headers transmitted from the transmitter and received after the first physical layer frame.

7. The gateway of claim 1, wherein physical layer frames of substantially equal duration comprise physical layer frames with substantially equal numbers of symbols.

8. The gateway of claim 1, wherein,

the first physical layer frame comprises a modified digital video broadcasting physical layer frame transmitted on a single carrier;

and

the header comprises a modified physical layer signaling (PLS) code including sub-channel identifier information.

9. The gateway of claim 8, wherein the encapsulator is further configured to include an identifier in a baseband header within the frame to allow further filtering at the first user terminal.

10. A processor for encapsulating a physical layer frame, the processor comprising:

a receiver configured to receive first data to be transmitted via a bent-pipe satellite destined for a first user terminal;

a bandwidth allocator, communicatively coupled with the receiver, and configured to;

determine an increased bandwidth requirement for the first user terminal;

increase a proportional allocation of physical layer frames including a sub-channel identifier associated with the first user terminal; and

control an encapsulator to generate the physical layer frames with the sub-channel identifier in the increased proportion;

an adaptive coding and modulation assignor, communicatively coupled with the receiver, and configured to assign a modulation and coding format for the first data responsive to second data identifying link conditions from the bent-pipe satellite to the first user terminal; and

the encapsulator, communicatively coupled with the receiver, the bandwidth allocator, and the adaptive coding and modulation assignor, and configured to;

utilize the assigned modulation and coding format to set a block size for a payload for a first physical layer frame, the block size set to produce a physical layer frame of substantially equal duration in reference to adjacent physical layer frames to be transmitted;

identify at least a portion of the first data for the payload for the first physical layer frame; and

encapsulate the at least a portion of the first data in the set block size for the payload of the first physical layer frame, the first physical layer frame including a header with the sub-channel identifier formatted to direct the first physical layer frame to the first user terminal and to provide information allowing the first user terminal to identify the first physical layer frame as a frame to be demodulated and decoded.

11. A method of producing a physical layer frame to be directed to a user terminal via a bent-pipe satellite, the method comprising:

receiving an identification of a modulation and coding format for data to be transmitted to a first user terminal via the bent-pipe satellite, the format assigned at least in part based on link conditions for the first user terminal;

determining an increased bandwidth requirement for the first user terminal;

increasing a proportion of physical layer frames including a sub-channel identifier associated with the first user terminal;

utilizing the identified modulation and coding format to set a block size for a payload for a first physical layer frame, the block size set to produce a physical layer frame of substantially equal duration in reference to adjacent physical layer frames to be transmitted;

encapsulating an amount of the data in the set block size to produce the payload for the first physical layer frame; and

appending a header to the payload to produce the first physical layer frame, the header formatted with the sub-channel identifier for determining that the first physical layer frame is directed to the first user terminal before the payload is demodulated and decoded.

12. The method of claim 11, further comprising:

storing a table associating each of a plurality of different modulation and coding formats with respective block sizes; and

accessing the stored table to identify the block size.

13. The method of claim 11, further comprising:

generating a header identifier to allow the first user terminal to identify boundaries of the payload for the first physical layer frame and to filter the first physical layer frame based on the header identifier.

14. The method of claim 11, further comprising:

setting the sub-channel identifier to provide information allowing the first user terminal to omit a header identifier detection analysis at known header identifier locations in a set of physical layer frames received after the first physical layer frame.

15. The method of claim 11, further comprising:

setting the sub-channel identifier to provide information allowing the first user terminal to;

identify a location for a next header identifier detection analysis in a set of physical layer frames received after the first physical layer frame; and

identify the first physical layer frame as a frame to be demodulated and decoded.

16. The method of claim 11, further comprising:

generating the header comprising a physical layer header including the sub-channel identifier formatted to allow the respective user terminals to filter the first physical layer frame before the payload of the first physical layer frame is decoded.

17. The method of claim 11, further comprising:

varying spacing between a plurality of additional headers to be transmitted.

18. The method of claim 11, further comprising:

upconverting the first physical layer frame; and

transmitting the upconverted frame to the bent-pipe satellite.

19. A bent-pipe satellite communications system comprising:

a gateway comprising;

a bandwidth allocator, configured to;

determine an increased bandwidth requirement for a user terminal;

increase a proportional allocation of physical layer frames including a sub-channel identifier associated with the user terminal; and

control an encapsulator to generate the physical layer frames with the sub-channel identifier in the increased proportion; and

an adaptive coding and modulation assignor communicatively coupled with the bandwidth allocator, and configured to assign a modulation and coding format for data destined for the user terminal responsive to link conditions between the bent-pipe satellite and the user terminal;

the encapsulator, communicatively coupled with the bandwidth allocator and the adaptive coding and modulation assignor, and configured to;

utilize the assigned modulation and coding format to set a block size for a payload for a physical layer frame, the block size set to produce a physical layer frame of substantially equal duration in reference to adjacent physical layer frames transmitted from the gateway; and

encapsulate at least a portion of the data in the set block size for the payload of the physical layer frame, the physical layer frame including a header with the sub-channel identifier formatted to direct the physical layer frame to the user terminal and to provide information allowing the user terminal to identify the physical layer frame as a frame to be demodulated and decoded; and

a transmitter, communicatively coupled with the encapsulator, and configured to upconvert and transmit the physical layer frame as a wireless signal to the bent-pipe satellite;

the bent-pipe satellite, communicatively coupled with the user terminal and the gateway, and configured to receive the wireless signal from the gateway and retransmit the received signal to the user terminal; and

the user terminal configured to receive the signal transmitted via the bent-pipe satellite.

20. A device configured to transmit a signal to respective user terminals via a bent-pipe satellite, the device comprising:

means for receiving first data to be transmitted via the bent-pipe satellite destined for a first user terminal and for receiving second data identifying link conditions for the first user terminal;

means for determining an increased bandwidth requirement for the first user terminal;

means for increasing a proportional allocation of physical layer frames including a sub-channel identifier associated with the first user terminal;

means for assigning a modulation and coding format for the first data responsive to the link conditions;

means for utilizing the modulation and coding format to set a block size for a payload for a first physical layer frame, the block size set to produce a physical layer frame of substantially equal duration in reference to adjacent physical layer frames to be transmitted from the device;

means for encapsulating at least a portion of the first data in a first block having the set block size for the payload of the first physical layer frame, the first physical layer frame including a header with the sub-channel identifier formatted to direct the first physical layer frame to the first user terminal and to provide information allowing the first user terminal to identify the first physical layer frame as a frame to be demodulated and decoded; and

means for upconverting and transmitting the first physical layer frame to the bent-pipesatellite.

21. A device for producing a physical layer frame to be directed to a user terminal via a bent-pipe satellite, the device comprising:

means for determining an increased bandwidth requirement for the first user terminal;

means for increasing a proportion of physical layer frames including the sub-channel identifier associated with the first user terminal;

means for receiving an identification of a modulation and coding format for data to be transmitted to a first user terminal, the format assigned at least in part based on link conditions for the first user terminal;

means for utilizing the identified modulation and coding format to set a block size for a payload for a first physical layer frame, the block size set to produce a physical layer frame of substantially equal duration in reference to adjacent physical layer frames to be transmitted;

means for encapsulating an amount of the data in the set block size to produce the payload for the first physical layer frame; and

means for appending a header to the payload to produce the first physical layer frame, the header formatted with the sub-channel identifier for determining that the first physical layer frame is directed to the first user terminal before the payload is demodulated or decoded.

22. The device of claim 21, further comprising:

means for upconverting and transmitting the first physical layer frame to the bent-pipe satellite.

23. The device of claim 21, further comprising:

means for receiving the amount of data to be transmitted via the bent-pipe satellite destined for the first user terminal and for receiving an identification of link conditions for the first user terminal; and

means for assigning the modulation and coding format for the first data responsive to the link conditions.