Aggregate rate modem

• US 8,243,651 B2
• Filed: 07/16/2008
• Issued: 08/14/2012
• 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:
  US12/174,525
• Publication Number:
  US 20090022087A1
• Time in Patent Office: 1,490 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 terminal to receive a signal from a satellite, the terminal comprising:

a receiver configured to receive the signal transmitted via the satellite;

a header processor, communicatively coupled with the receiver, and configured to;

receive a digitized stream comprising a physical layer signal representative of the received signal;

process the digitized stream to detect a first physical layer header portion of the digitized stream; and

demodulate and decode the first physical layer header portion to identify a first sub-channel identifier for a physical layer payload associated with the first physical layer header portion;

a buffer, communicatively coupled with the receiver and a filter, and configured to store at least part of the digitized stream comprising the physical layer payload associated with the first physical layer header portion; and

the filter, communicatively coupled with the header processor, and configured to;

store one or more sub-channel identifiers indicating whether an associated physical layer payload is to be demodulated and decoded by the terminal;

determine that the first sub-channel identifier matches one or more of the stored identifiers indicating that an associated physical layer payload should be filtered before demodulation and decoding; and

filter the physical layer payload associated with the first physical layer header portion by controlling the buffer to overwrite the stored part of the digitized stream comprising the physical layer payload before the physical layer payload is forwarded for demodulation or decoding to prevent demodulation and decoding.

2. The terminal of claim 1, wherein,

the header unit processor is further configured to demodulate and decode a second physical layer header portion of the digitized stream to detect a second sub-channel identifier for a physical layer payload associated with the second physical layer header portion;

and

the filter is further configured to;

determine that the second sub-channel identifier matches one or more of the stored identifiers indicating that an associated physical layer payload should be demodulated and decoded; and

forward the physical layer payload associated with the second physical layer header portion for demodulation and decoding.

3. The terminal of claim 2, further comprising:

a demodulator configured to receive and demodulate the forwarded physical layer payload associated with the second physical layer header portion; and

a decoder configured to decode the demodulated physical layer payload,

wherein the demodulator and decoder are each configured to demodulate and decode only a subset of a plurality of physical layer payloads in the digitized stream.

4. The terminal of claim 3, wherein the demodulator and decoder are each configured to demodulate and decode at most one in four of the plurality of physical layer payloads in the digitized stream.

5. The terminal of claim 1, wherein the header processor is further configured to process the digitized stream to allow other physical layer header portions of the digitized stream to pass without detection.

6. The terminal of claim 1, wherein,

the received signal comprises a modified digital video broadcasting signal carried on a single carrier;

the first physical layer header portion comprises a start of frame (SOF) pattern and a modified physical layer signaling (PLS) code including sub-channel identifier information.

7. The terminal of claim 1, wherein a subset of the digitized stream comprising the physical layer payload associated with the first physical layer header portion is not demodulated or decoded.

18. The terminal of claim 1, wherein the first physical layer header portion comprises a known unique identifier known at the terminal before reception.

19. The terminal of claim 18, wherein the first physical layer header portion further comprises physical layer signaling information identifying a modulation and coding format.

20. The terminal of claim 18, wherein the first physical layer header portion further comprises physical layer signaling information identifying sub-channel identifier information.

8. A processor for processing a digitized representation of a signal received from a satellite, the processor comprising:

a header processor configured to;

receive a digitized stream comprising a physical layer signal representative of the signal received from the satellite;

process the digitized stream to detect a first physical layer header portion of the digitized stream;

detect from the first physical layer header portion a first sub-channel identifier for a physical layer payload associated with the first physical layer header portion; and

instruct a buffer to store at least part of the digitized stream comprising the physical layer payload associated with the first physical layer header portion; and

a filter, communicatively coupled with the header processor, and configured to;

access a stored listing of one or more sub-channel identifiers indicating whether an associated physical layer payload is to be demodulated and decoded;

determine whether the first sub-channel identifier matches one or more of the listed identifiers that indicate an associated physical layer payload is to be demodulated and decoded;

and filter the digitized stream comprising the physical layer payload associated with the first physical layer header portion by controlling the buffer to overwrite the stored part of the digitized stream comprising the physical layer payload before the physical layer payload is forwarded for demodulation or decoding to prevent the filtered payload from being demodulated and decoded.

9. The processor of claim 8, wherein,

the header processor is further configured to demodulate and decode a second physical layer header portion of the digitized stream to detect a second sub-channel identifier for a physical layer payload associated with the second physical layer header portion;

and

the filter is further configured to;

determine that the second sub-channel identifier matches one or more of the listed identifiers indicating that an associated physical layer payload is to be demodulated and decoded; and

forward the physical layer payload associated with the second physical layer header portion for demodulation and decoding.

10. The processor of claim 8, further comprising:

a demodulator configured to receive and demodulate the forwarded physical layer payload associated with the second physical layer header; and

a decoder configured to decode the demodulated physical layer payload,

wherein the demodulator and decoder are each configured to demodulate and decode only a subset of a plurality of physical layer payloads in the digitized stream.

11. A method of processing a digital representation of a signal received from a satellite, the method comprising:

receiving a digitized stream comprising a physical layer signal representative of the signal received from the satellite;

identifying a first physical layer header portion of the digitized stream;

demodulating and decoding the physical layer header portion to identify a sub-channel identifier for a physical layer payload associated with the physical layer header portion;

buffering at least part of the digitized stream comprising the physical layer payload;

determining whether the sub-channel identifier corresponds to an indication that an associated physical layer payload is to be filtered from demodulation and decoding; and

filtering the digitized stream comprising the physical layer payload by overwriting the buffered part of the digitized stream comprising the physical layer payload to prevent the payload from being demodulated or decoded, responsive to the determining step.

12. The method of claim 11, further comprising:

forwarding the physical layer payload for demodulation and decoding, responsive to the determining step.

13. The method of claim 12, further comprising:

demodulating the forwarded physical layer payload associated with the physical layer header portion; and

decoding the demodulated physical layer payload,

wherein the demodulating and decoding steps are performed at a rate less than a rate payload data is received via the digitized stream.

14. The method of claim 11, further comprising:

processing the digitized stream to allow other header identifiers identifying other physical layer header portions of the digitized stream to pass without detection, wherein the other header identifiers comprise different identifiers than the first header identifier.

15. The method of claim 11, further comprising:

omitting a physical layer header detection analysis at one or more known physical layer header identifier locations.

16. The method of claim 11, further comprising:

performing symbol timing recovery and course carrier frequency recovery to produce the digitized signal.

17. A satellite communications system comprising:

a gateway configured to transmit a signal sent to a satellite for retransmission to a terminal;

the satellite, in communication with the terminal and the gateway, and configured to receive the signal from the gateway and retransmit the received signal to the terminal; and

the terminal comprising;

a receiver configured to receive the retransmitted wireless signal from the satellite;

a header processor, communicatively coupled with the receiver, and configured to;

receive a digitized stream comprising a physical layer signal representative of the signal from the satellite;

process the digitized stream to recognize a header identifier identifying a physical layer header portion of the digitized stream; and

demodulate and decode the physical layer header portion to identify a sub-channel identifier for payload associated with the physical layer header portion;

a buffer, communicatively coupled with the receiver and a filter, and configured to store at least part of the digitized stream comprising the payload associated with the physical layer header portion; and

the filter, communicatively coupled with the header processor, and configured to;

access a listing of one or more sub-channel identifiers indicating whether an associated physical layer payload is to be demodulated and decoded;

determine that the identified sub-channel identifier matches at least one of the listed identifiers indicating the payload associated with the physical layer header portion is to be prevented from being demodulated and decoded; and

filter the digitized stream comprising the payload associated with the physical layer header portion by controlling the buffer to overwrite the stored part of the digitized stream comprising said payload before said payload is forwarded for demodulation or decoding to prevent said payload from being demodulated and decoded.

21. A device to receive a signal from a satellite, the device comprising:

a receiver configured to receive a digitized stream comprising a physical layer signal representative of the signal received via the satellite;

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

process the digitized stream to detect a physical layer header portion of the digitized stream;

process the physical layer header portion to identify a received sub-channel identifier for a physical layer payload associated with the physical layer header portion; and

determine, responsive to the received sub-channel identifier, whether to;

demodulate and decode the physical layer payload associated with the physical layer header portion;

or

discard the physical layer payload associated with the physical layer header portion;

a memory communicatively coupled with the processor and configured to buffer at least part of the digitized stream comprising the physical layer payload; and

a filter communicatively coupled with the processor and configured to filter the physical layer payload associated with the physical layer header portion by overwriting the buffered part of the digitized stream to prevent the payload from being demodulated and decoded.

22. The device of claim 21, wherein the processor is further configured to forward the physical layer payload for demodulation and decoding responsive to the determination.

23. The device of claim 22, further comprising:

a demodulator communicatively coupled with the processor and configured to demodulate the forwarded physical layer payload associated with the physical layer header portion; and

a decoder communicatively coupled with the demodulator and configured to decode the demodulated physical layer payload.

24. The device of claim 21, wherein the processor is configured to process the physical layer header portion to identify the received sub-channel identifier by:

demodulating and decoding the physical layer header portion to identify the received sub-channel identifier.

25. The device of claim 21, wherein the device comprises a processor.

26. The device of claim 21, wherein the device comprises a terminal.

27. A device to receive a signal from a satellite, the device comprising:

means for receiving a digitized stream comprising a physical layer signal representative of the signal received via the satellite;

means for processing the digitized stream to detect a physical layer header portion of the digitized stream;

means for processing the physical layer header portion to identify a received sub-channel identifier for a physical layer payload associated with the physical layer header portion;

means for buffering at least part of the digitized stream comprising the physical layer payload;

means for determining, responsive to the received sub-channel identifier, whether to A) demodulate and decode the physical layer payload associated with the physical layer header portion, or B) discard the physical layer payload associated with the physical layer header portion; and

means for filtering the digitized stream comprising the physical layer payload to discard the physical layer payload by overwriting the buffered part of the digitized stream comprising the physical layer payload and thereby prevent the payload from being demodulated and decoded.

28. The device of claim 27, further comprising:

means for forwarding the physical layer payload for demodulation and decoding responsive to the determination.

29. The device of claim 28, wherein the means for processing the physical layer header portion to identify the received sub-channel identifier comprises:

means for demodulating and decoding the physical layer header portion to identify the received sub-channel identifier.