High Data Rate Multiplexing Satellite Stream to Low Data Rate Subscriber Terminals

• US 20090290536A1
• Filed: 03/26/2009
• Published: 11/26/2009
• Est. Priority Date: 09/26/2006
• Status: Active Grant

• Current Assignee: ViaSat Incorporated
• Original Assignee: ViaSat Incorporated
• Inventors: Dankberg, Mark D., Eidenschink, Thomas, Jaska, Kristi Ann
• Granted Patent: US 8,159,994 B2
• Time in Patent Office: Days
• US Class Current: 370/321
• CPC Class Codes: H04B 7/18582 Arrangements for data linking, i.e. for data framing, for error recovery, for multiple access

Abstract

A satellite modem for broadband communication. The satellite modem receives a satellite signal on a single carrier from a satellite. The satellite signal is divided by time division multiplexing into physical sub-channels encapsulating logical downstreams. The satellite modem includes a filter which removes a subset of the physical sub-channels intended for the subscriber terminal. The satellite modem includes a demodulator, a decoder, and a medium access channel. The MAC processes the logical downstreams.

Claims

1. A satellite modem comprising:

means for receiving from a satellite a single carrier signal that is time division multiplexed into a plurality of physical layer sub-channels that encapsulate respective associated logical downstreams;

filter means communicatively coupled to the receiving means for removing from the received single carrier satellite signal a subset of the plurality of physical layer sub-channels and for passing a second subset of the plurality of physical layer sub-channels associated with the satellite modem; and

means communicatively coupled to an output of the filter means for processing the second subset of the plurality of physical layer sub-channels and for de-encapsulating an associated logical downstream.

2. The satellite modem according to claim 1, wherein the means for processing comprises a medium access controller (MAC) and is configured to process the single carrier signal with the singe carrier signal using adaptive coding and modulation.

3. The satellite modem according to claim 1, wherein the means for processing is configured to process the single carrier signal with the single carrier signal having a data rate greater than one gigabits per second.

4. The satellite modem according to claim 1, wherein the means for processing is configured to process the single carrier signal with the single carrier signal having a code rate and/or a modulation that varies over time.

5. The satellite modem according to claim 1, wherein the filter means is configured to perform time-division demultiplexing.

6. A satellite communication system operating at a data throughput rate higher than a plurality of satellite modems, the satellite communication system comprising:

an antenna configured to transmit a forward channel of information toward the plurality of satellite modems, wherein the forward channel comprises;

a first logical sub-channel, and

a second logical sub-channel, wherein the first and second logical sub-channels are time division multiplexed within the forward channel;

a first plurality of satellite modems configured to receive the forward channel, wherein;

the first plurality of satellite modems is part of the plurality of satellite modems, and

each of the first plurality of satellite modems is configured to completely decode the first logical sub-channel but not completely decode the second logical sub-channel;

a second plurality of satellite modems configured to receive the forward channel, wherein;

the second plurality of satellite modems is part of the plurality of satellite modems, and

each of the second plurality of satellite modems is configured to completely decode the second logical sub-channel but not completely decode the first logical sub-channel.

7. The satellite communication system operating at the data throughput rate higher than the plurality of satellite modems according to claim 6, wherein the plurality of satellite modems operate at a lower rate than the forward channel.

8. The satellite communication system operating at the data throughput rate higher than the plurality of satellite modems according to claim 6, wherein the forward channel is transported with a single carrier.

9. The satellite communication system operating at the data throughput rate higher than the plurality of satellite modems according to claim 6, wherein the forward channel has a coding and a modulation that varies over time.

10. The satellite communication system operating at the data throughput rate higher than the plurality of satellite modems according to claim 6, wherein each of the first plurality of satellite modems is configured to screen out the second logical sub-channel before decode completes.

11. The satellite communication system operating at the data throughput rate higher than the plurality of satellite modems according to claim 6, wherein the forward channel uses an adaptive coding and modulation.

12. The satellite communication system operating at the data throughput rate higher than the plurality of satellite modems according to claim 6, wherein the forward channel has a data rate greater than one gigabits per second.

13-17. -17. (canceled)

18. A method performed at a satellite modem, the method comprising:

receiving from a satellite a forward channel signal comprising a plurality of sub-channels multiplexed within the forward channel, the satellite modem corresponding to a respective sub-channel of the plurality of sub-channels;

processing the forward channel signal to demultiplex a first sub-channel of the plurality of sub-channels;

partially decoding before processing by a medium access controller (MAC), the first sub-channel sufficiently to determine the first sub-channel is associated with the satellite modem; and

decoding a remainder of the first sub-channel.

19. The method of claim 18 further comprising forwarding, to another device, sub-channels determined not to be associated with the satellite modem.

20. The method of claim 18 wherein receiving the forward channel signal comprises receiving a signal using adaptive coding and modulation.

21. The method of claim 18 wherein receiving the forward channel signal comprises receiving a signal whose coding and modulation change over time.

22. A satellite modem comprising:

an input configured to receive signals from a satellite, the signals forming a forward channel and including first and second sub-channels;

a splitter communicatively coupled to the input and configured to separate headers of the signals from payloads of the signals and to output the headers as a first output and to output the payloads as a second output;

a demodulator communicatively coupled to the splitter to receive the first output and configured to demodulate the headers;

a controller communicatively coupled to the demodulator and configured to analyze demodulated headers from the demodulator and to produce a first indication that an analyzed header corresponds to a sub-channel allocated to the satellite modem; and

a buffer communicatively coupled to the splitter and the controller and configured to store a payload corresponding to the analyzed header in response to the first indication.

23. The modem of claim 22 further comprising a medium access controller coupled to the buffer and configured to process the stored payload.

24. The modem of claim 22 wherein the controller is further configured to produce a second indication that the analyzed header does not correspond to the sub-channel allocated to the satellite modem, the satellite modem further comprising an output communicatively coupled to the splitter and configured to communicatively couple to the a device and to transfer the analyzed header toward the device.

25. A satellite modem comprising:

an input configured to receive signals from a satellite, the signals forming a forward channel and including first and second sub-channels;

a digitizer communicatively coupled to the input and configured to digitize the received signals;

a controller communicatively coupled to the digitizer and having access to stored information regarding the first sub-channel that is allocated to the satellite, the controller being configured to actuate the digitizer to digitize the first sub-channel but not the second sub-channel; and

a buffer communicatively coupled to the digitizer and configured to store the digitized first sub-channel.

26. The modem of claim 25 further comprising a medium access controller coupled to the buffer and configured to process the stored payload.

27. The modem of claim 26 wherein the controller is further configured to cause the splitter, in response to determining that the analyzed header does not correspond to the satellite modem, to transfer the analyzed header toward an output configured to couple to another device.