Claims
- 1. A method of communicating between network elements in a broadcast communication system comprising:
removing at least one sub-carrier to form an intra-spectral gap within a multi-carrier broadcast signal; and employing the intra-spectral gap to provide a bi-directional channel adapted to propagate ancillary data signals.
- 2. The method of claim 1 wherein the step of removing comprises:
filtering the multi-carrier broadcast signal to remove the at least one sub-carrier from the multi-carrier broadcast signal.
- 3. The method of claim 1 wherein the step of removing comprises:
removing the at least one sub-carrier from the multi-carrier broadcast signal by affecting inverse fast Fourier transform (IFFT) coefficients within a modulator.
- 4. The method of claim 1 wherein the step of employing comprises:
transmitting ancillary data signals over the bi-directional channel from a remote device to another network element.
- 5. The method of claim 4 wherein the step of employing further comprises:
transmitting ancillary data signals over the bi-directional channel from a transmission system to another network element.
- 6. The method of claim 5 wherein the step of transmitting ancillary data signals from the transmission system comprises at least one of:
propagating ancillary data signals over the bi-directional channel; encoding ancillary data signals with broadcast data corresponding to the multi-carrier broadcast signals; and modulating a selected subset of sub-carriers in the multi-carrier broadcast signal with ancillary data symbols.
- 7. The method of claim 4 wherein the other network element comprises a network element selected from the group consisting of a transmission system, a wireless base station, and a remote device.
- 8. The method of claim 1 wherein the multi-carrier broadcast signal comprises a coded orthogonal frequency division multiplexed (COFDM) signal.
- 9. The method of claim 4 further comprising:
comparing information derived from a megaframe initialization packet (MIP) with an external time reference to compute signal timing information; and synchronizing the ancillary data signals with the multi-carrier broadcast signal using the signal timing information.
- 10. A broadcast communication system comprising:
a transmission system for broadcasting a multi-carrier signal, the transmission system removing at least one sub-carrier from the multi-carrier signal to create a bi-directional channel; and a plurality of remote devices for transmitting and receiving ancillary data signals using the bi-directional channel.
- 11. The system of claim 10 wherein the transmission system comprises:
an encoder for encoding broadcast data; a modulator for generating the multi-carrier signal from the encoded broadcast data; and an ancillary data transceiver for transmitting and receiving ancillary data signals.
- 12. The system of claim 11 wherein the modulator is adapted to remove the at least one sub-carrier from the multi-carrier signal by affecting inverse fast Fourier transform (IFFT) coefficients in the modulator.
- 13. The system of claim 11 further comprising:
a filter device for removing the at least one sub-carrier from the multi-carrier signal.
- 14. The system of claim 13 wherein the filter device comprises:
a surface acoustic wave (SAW) filter; and a frequency converter for positioning the frequency response of the SAW filter within the spectrum of the multi-carrier signal.
- 15. The system of claim 10 wherein the transmission system comprises:
an encoder for encoding broadcast data and ancillary data; a modulator for generating the multi-carrier signal from the encoded broadcast and ancillary data; and an ancillary data receiver for receiving ancillary data signals.
- 16. The system of claim 10 wherein the transmission system comprises:
a single frequency network (SFN) adapter for inserting a sequence of megaframe initialization packets (MIPs) into the multi-carrier signal.
- 17. The system of claim 16 wherein each of the plurality of remote devices comprises:
a timing device for generating an external time reference signal; and a synchronization device for comparing time information in the sequence of MIPs with the external time reference signal to synchronize ancillary data signals with the multi-carrier signal.
- 18. The system of claim 10 further comprising:
a network of wireless base stations for receiving ancillary data signals supplied by the plurality of remote devices.
- 19. The system of claim 10 wherein the broadcast communication system comprises a terrestrial digital video broadcast (DVB-T) system and the multi-carrier signal comprises a coded orthogonal frequency division multiplexed (COFDM) signals.
- 20. An apparatus for providing bi-directional channels in a broadcast communication system comprising:
a modulator for generating a multi-carrier broadcast signal; a means for removing at least one sub-carrier from the multi-carrier broadcast signal to create a bi-directional channel; and an ancillary data transceiver for transmitting and receiving ancillary data signals using the bi-directional channel.
- 21. The apparatus of claim 20 wherein the means for removing at least one sub-carrier comprises circuitry within the modulator for affecting inverse fast Fourier transform (IFFT) coefficients to remove the at least one sub-carrier.
- 22. The apparatus of claim 20 wherein the means for removing at least one sub-carrier comprises a filter device for removing a plurality of sub-carriers from the multi-carrier broadcast signal.
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims benefit of U.S. provisional patent applications serial Nos. 60/339,671 and 60/339,672, both filed Dec. 13, 2001. Each of the aforementioned patent applications is herein incorporated by reference.
GOVERNMENT RIGHTS IN THIS INVENTION
[0002] This invention was funded in part by the U.S. government under contract number DAAB07-01-9-L504, U.S. Army Communications-Electronic Command (CECOM). The U.S. government may have certain rights in this invention.
Provisional Applications (2)
|
Number |
Date |
Country |
|
60339671 |
Dec 2001 |
US |
|
60339672 |
Dec 2001 |
US |