Virtual channel satellite communication system with improved bandwidth efficiency

• US 20030143995A1
• Filed: 12/10/2002
• Published: 07/31/2003
• Est. Priority Date: 11/12/1999
• Status: Abandoned Application

• Current Assignee: Virtual Satellite Corporation
• Original Assignee: Virtual Satellite Corporation
• Inventors: Bush, John, Friedman, Robert F., Thacker, John C., Garner, Greg
• Application Number:
  US10/316,591
• Publication Number:
  US 20030143995A1
• Time in Patent Office: Days
• US Class Current: 455/429
• CPC Class Codes: H04B 7/18578 Satellite systems for providing broadband data service to individual earth stations for selecting H04W; provisions for broadband connection, H04Q11/0478

Abstract

Presented is a satellite communication system that allows aggregation of available transponder bandwidth. A channel signal is divided into subparts (e.g., data packets), formatted (e.g., encapsulated) and distributed among a plurality of subchannels according to bandwidth availability. Each subpart is encoded with information that facilitates proper reconstruction of the original channel data at the receiving station. The subchannels are transmitted to a receiving station, which synchronizes the subchannels and decapsulates the subparts. The receiving station includes a subchannel combiner which combines the decapsulated subparts in select subchannels to produce a reconstructed version of a user-selected channel signal. A controller in the receiving station identifies the subchannels to be combined in response to user selection and sends commands to a subchannel combiner. The receiving station also includes a connectivity matrix that discards the unnecessary subchannels before demodulation and reconstruction, reducing the number of demodulators in the system.

Claims

1. A method of satellite communication that allows efficient use of available bandwidth, the method comprising:

receiving a channel signal;

regrouping data in the channel signal into subparts;

dividing the subparts among subchannels according to available bandwidth in each of the subchannels; and

transmitting the subparts to satellite transponders via the n subchannels.

2. The method of claim 1, wherein regrouping the data in the channel signal comprises:

fragmenting the channel signal into data packets; and

encapsulating each of the data packets, wherein the encapsulating includes adding a header that contains information useful for combining the data packets to reconstruct the channel signal.

3. The method of claim 2, wherein fragmenting the channel signal comprises at least one of combining contents of two of the data packets and dividing a content of one of the data packets.

4. The method of claim 2 further comprising assigning each of the encapsulated data packets to one of the subchannels that has available bandwidth.

5. The method of claim 1, further comprising multiplexing a plurality of channel signals to form a virtual channel before dividing the channel signal into subparts.

6. The method of claim 5 further comprising adding conditional access data during the multiplexing, wherein the conditional access data identifies whether an end user equipment is allowed to access each of the subchannels.

7. The method of claim 5 further comprising separately encapsulating each channel signal before the multiplexing.

8. The method of claim 1 further comprising adding network configuration data upon the dividing, wherein the network configuration data includes a map correlating the channel signal to select subchannels.

9. The method of claim 1 further comprising separately modulating each of the subchannels so that each of the subchannels is in a preselected frequency range.

10. The method of claim 1 further comprising:

receiving the subparts transmitted via the subchannels;

identifying a user selected channel;

categorizing the subchannels into a first category and a second category wherein the first category contains subparts needed to reconstruct the user selected channel and the second category contains subparts to be discarded; and

combining the subparts in the first category to reconstruct the channel signal.

11. The method of claim 10 further comprising:

determining an order in which the subparts are to be combined;

defragmenting the subparts; and

decapsulating the subparts.

12. The method of claim 10 wherein categorizing the subchannels further comprises reading a network configuration map that identifies which subchannels contain subparts for the user selected channel.

13. A method of satellite communication that allows efficient use of available bandwidth, the method comprising:

receiving subparts of a channel signal transmitted via subchannels over satellite transponders;

identifying a user selected channel;

categorizing the subchannels into a first category and a second category wherein the first category contains subparts needed to reconstruct the user selected channel and the second category contains subparts to be discarded; and

combining the subparts in the first category to reconstruct the channel signal.

14. The method of claim 13 further comprising:

determining an order in which the subparts are to be combined;

defragmenting the subparts; and

decapsulating the subparts.

15. The method of claim 14 wherein defragmenting the subparts comprises at least one of combining content from two data frames and dividing content of one data frame.

16. The method of claim 14 wherein decapsulating the subparts comprises taking off a header from each of the data frames.

17. The method of claim 13 wherein there are multiple channel signals further comprising reading a network configuration map that identifies which subchannels contain subparts for the user selected channel.

18. A satellite communications system which provides an enhanced digital communication channel, the satellite communications system comprising:

a multiplexer multiplexing a plurality of channel signals to create a virtual channel;

a channel splitter coupled to the multiplexer, the channel splitter dividing the virtual channel into a plurality of subparts according to available bandwidth of each of the subchannels and distributing the subparts among subchannels; and

a plurality of uplink transmitters, each of the plurality of uplink transmitters coupled to the channel splitter, the uplink transmitters transmitting the subchannels toward respective satellite transponders.

19. The satellite communications system of claim 18 further comprising encapsulators that are coupled to the multiplexer, wherein each of the encapsulators fragments and encapsulates each of the plurality of channel signals.

20. The satellite communications system of claim 18 further comprising a plurality of modulators coupled to the channel splitter, each of the plurality of modulators modulating one of the subchannels.

21. The satellite communications system of claim 18 further comprising a conditional access system coupled to the multiplexer, the conditional access system providing information regarding whether a particular receiving station is allowed to receive a particular channel.

22. The satellite communications system of claim 18 further comprising a network configuration management system coupled to the channel splitter, the network configuration management system providing a map indicating the subchannels that carry content for each channel.

23. The satellite communications system of claim 18 further comprising a network configuration management system coupled to the channel splitter and the at least one receiving antenna and providing a map between the subchannels and a plurality of virtual channels.

24. The satellite communications system of claim 18, wherein each of the subparts is a 188-byte data frame including a 4-byte header.

25. The satellite communications system of claim 18, wherein the subparts are data frames in accordance with one of MPEG 1, MPEG 2, MPEG 3, MPEG 4 and Ethernet standards.

26. The satellite communications system of claim 18, wherein each of the subparts includes a header that is sent over the satellite transponders, the header containing information used for the reconstruction of the virtual channel.

27. The satellite communications system of claim 18, wherein data rates for the subchannels are such that a sum of the data rates of the subchannels is approximately equal to the data rate of the channel signal.

28. The satellite communications system of claim 18, wherein bandwidths for the subchannels are such that a sum of the bandwidths of the subchannels is approximately equal to the bandwidth of the channel signal.

29. The satellite communications system of claim 18, wherein at least some of the subchannels travel at different data rates and bandwidths.

30. The satellite communications system of claim 18, wherein the channel splitter comprises:

an input data splitter thread for dividing the channel signal into the subchannels;

a transmit data thread coupled to the input data splitter for directing the subparts into one of transmit data buffers; and

a plurality of transmit data buffers coupled to the transmit data thread, each of the transmit data buffers holding subparts to be transmitted to one of the respective satellite transponders.

31. The satellite communications system of claim 18 further comprising a graphic user interface coupled to the input data splitter thread and the transmit data thread.

32. The satellite communications system of claim 18 further comprising:

at least one receiving antenna collecting signals from the respective satellite transponders; and

a subchannel combiner coupled to the at least one receiving antenna, the subchannel combiner combining select ones of the subchannels into a reconstruction of the virtual channel.

33. The satellite communications system of claim 32 further comprising decapsulators coupled to the subchannel combiner, wherein each of the decapsulators defragments and decapsulates received subparts.

34. The satellite communications system of claim 32 further comprising a controller coupled to the subchannel combiner, the controller identifying the select subchannels to be combined to reconstruct a user-selected channel and sending corresponding commands to the subchannel combiner.

35. The satellite communications system of claim 32 further comprising a decoder coupled to the subchannel combiner to decode the virtual channel and extract actual program content.

36. The system of claim 32, wherein the receiving station further comprises:

a plurality of tuners coupled to the at least one receiving antenna and adjusting the frequency of each of the received subchannels;

a plurality of demodulators, each demodulator coupled to a corresponding tuner output for demodulating the corresponding tuner output and creating a bit stream corresponding to the content of a respective subchannel; and

a plurality of delay means coupled to the plurality of demodulators and delaying the subchannels so that the subchannels are synchronized for proper reconstruction.

37. The satellite communications system of claim 36 further comprising a plurality of modulators coupled to the channel splitter, wherein the plurality of modulators and the plurality of demodulators mark a frame as NULL when the content of the frame is unavailable, and the subchannel combiner discards a frame marked as NULL.

38. The system of claim 32 further comprising:

a nonvolatile memory for storing information about the frequency and propagation delay properties of the subchannels; and

an output buffer coupled to the subchannel combiner.

39. The satellite communications system,of claim 32 further comprising a connectivity matrix for discarding subchannels that are not needed to reconstruct the selected channel.

40. The satellite communications system of claim 32, wherein the channel splitter transmits information concerning the number and the data rates of the subchannels to the subchannel combiner, the information being encoded in a header for each of the subparts.

41. The satellite communications system of claim 32, wherein the subchannel combiner comprises:

a plurality of receive data buffers for receiving subchannel signals from the plurality of demodulators, wherein the subchannel signals include formatted subparts;

a plurality of receive data threads coupled to the plurality of receive data buffers for putting the formatted subparts in an order that facilitates recombination;

a pre-combination output data buffer coupled to the plurality of receive data threads for converting the framed subparts into raw data packets substantially similar to the raw data packets of the channel signal; and

an output combiner thread coupled to the output data buffer for combining the raw data packets into a reconstructed channel signal.

42. A satellite communications system which provides an enhanced digital communication channel, the satellite communications system comprising:

at least one receiving antenna collecting channel signals from n satellite transponders, wherein the channel signals are received as subparts divided among n subchannels; and

a subchannel combiner coupled to the at least one receiving antenna, the subchannel combiner combining select ones of the n subchannels into a reconstruction of the virtual channel.

43. The satellite communications system of claim 42 further comprising a controller coupled to the subchannel combiner, the controller identifying the select subchannels to be combined to reconstruct a user-selected channel and sending commands to the subchannel combiner.

44. The system of claim 42, wherein the receiving station further comprises:

a plurality of tuners coupled to the at least one receiving antenna and adjusting the frequency of each of the received subchannels;

a plurality of demodulators, each demodulator coupled to a corresponding tuner output for demodulating the corresponding tuner output and creating a bit stream corresponding to the content of a respective subchannel; and

a plurality of delay means coupled to the plurality of demodulators and delaying the subchannels so that the subchannels are synchronized for proper reconstruction.

45. The system of claim 42 further comprising:

a nonvolatile memory for storing information about the frequency and propagation delay properties of the subchannels; and

an output buffer coupled to the subchannel combiner.

46. The satellite communications system of claim 42 further comprising a connectivity matrix for discarding subchannels that are not needed to reconstruct the selected channel.

47. The satellite communications system of claim 42 further comprising a connectivity matrix connecting n low noise block converter feed devices on the at least one receiving antenna to at least k demodulators, wherein 2n>

k and k is the number of subchannels that are combined to reconstruct a channel signal.

48. The satellite communications system of claim 42 further comprising a connectivity matrix connecting n low noise block converter feed devices on the at least one receiving antenna to at least 2k demodulators, wherein k is the number of subchannels that are combined to reconstruct a channel signal, allowing at least two different channels to be output to a plurality of end user devices.