Antenna diversity system

• US 20050276239A1
• Filed: 06/14/2004
• Published: 12/15/2005
• Est. Priority Date: 06/14/2004
• Status: Active Grant

• Current Assignee: Sirius XM Radio Inc. (Liberty Media Corporation)
• Original Assignee: XM Satellite Radio Incorporated (Liberty Media Corporation)
• Inventors: Marko, Paul, Smallcomb, Joseph, Wadin, Craig
• Granted Patent: US 7,447,171 B2
• Time in Patent Office: Days
• US Class Current: 370/316
• CPC Class Codes: H04B 7/18523 Satellite systems for providing broadcast service to terrestrial stations, i.e. broadcast satellite service arrangements specially adapted for satellite broadcast receiving H04H40/90; picture transmission via satellite H04N1/00103; television transmission via satellite H04N7/20
• CPC Class Codes: H04H 20/22 Arrangements for broadcast of identical information via plural broadcast systems
• CPC Class Codes: H04H 20/57 for mobile receivers
• CPC Class Codes: H04H 40/27 specially adapted for broadcast systems covered by groups H04H20/53 - H04H20/95
• CPC Class Codes: H04H 40/90 specially adapted for satellite broadcast receiving

Abstract

A system (100) for combining satellite and terrestrial signals from spatially diverse antennas (102 and 104) includes a tuner (101) and at least first and second analog to digital converters (103, 105) for converting at least two among the plurality of satellite signals and the terrestrial signal to a first digital stream and a second digital stream. A switch arrangement (106, 102 126) selectively switches among the first digital stream and the second digital stream before demodulating the digital streams using a plurality of algorithms (112, 122, 130) that selectively uses respectively demodulated signals of the first digital stream and the second digital stream to control (114, 124, 132) the switch arrangement to provide a plurality of multiplexed signals (161, 162, 163) that are combined (134) to form a combined signal (170). The combined signal can then be forward error corrected (136).

Claims

1. A method of combining satellite and terrestrial signals, comprising:

receiving a plurality of satellite signals and a terrestrial signal at a plurality of spatially diverse antennas;

converting at least one among the plurality of satellite signals and the terrestrial signal from an analog signal to a digital signal forming a first digital stream;

converting at least a second signal among the plurality of satellite signals and the terrestrial signal from an analog signal to a digital signal forming a second digital stream;

selectively switching among the first digital stream and the second digital stream before demodulating using a plurality of algorithms that selectively uses respectively demodulated signals of the first digital stream and the second digital stream to control the selective switching to provide a plurality of multiplexed signals; and

combining the multiplexed signals to form a combined signal.

2. The method of claim 1, wherein the method further comprises the step of forward error correcting the combined signal.

3. The method of claim 1, wherein the step of selectively switching before demodulating is a blind switching scheme.

4. A method of combining satellite and terrestrial signals, comprising:

receiving a plurality of satellite signals and at least one terrestrial signal using digital data streams from selectively chosen antennas among a plurality of spatially diverse antennas;

monitoring the plurality of satellite signals and at least one terrestrial signal using digital data streams from non-selected antennas among the plurality of spatially diverse antennas; and

selectively switching among several digital data streams from the plurality of spatially diverse antennas to enable processing of each of the plurality of satellite signals and the at least one terrestrial signal through the selectively chosen antennas and the non-selected antennas, wherein a selective switching decision is determined by a signal quality measurement comparison between a signal from a selectively chosen antenna and a signal from a non-selected antenna for each of the plurality of satellite signals and the at least one terrestrial signal.

5. The method of claim 4, wherein the method further comprises the step of demodulating a chosen digital data stream for each of the selectively chosen antennas.

6. The method of claim 4, wherein the non-selected antenna becomes a selectively chosen antenna and the selectively chosen antenna becomes a non-selected antenna when the signal quality measurement comparison indicates that the signal from the non-selected antenna is better than the signal from the selectively chosen antenna by a predetermined threshold.

7. The method of claim 5, wherein the method further comprises the step of combining the chosen digital data stream for each of the selectively chosen antennas to provide a combined demodulated signal.

8. The method of claim 7, wherein the method further comprises the step of forward error correcting the combined demodulated signal.

9. A method of combining satellite and terrestrial signals, comprising:

receiving a plurality of satellite signals and at least one terrestrial signal using a plurality of spatially diverse antennas;

demodulating the plurality of satellite signals and the at least one terrestrial signal to provide demodulated signals for at least two of the plurality of spatially diverse antennas for each of the plurality of satellite signals and the at least one terrestrial signal;

monitoring a signal quality of the demodulated signals coming from at least two of the plurality of spatially diverse antennas; and

combining the demodulated signals coming from at least two of the plurality of spatially diverse antennas using the signal quality measured for each demodulated signal to provide a combined signal.

10. The method of claim 9, wherein the method further comprises the step of forward error correcting the combined signal.

11. The method of claim 9, wherein the step of combining is a maximal ratio combining step using a weighting function determined from the signal quality of the demodulated signals coming from at least two of the plurality of spatially diverse antennas.

12. The method of claim 11, wherein the step of maximal ratio combining is done separately for the plurality of satellite signals to provide a combined satellite signal and for the at least one terrestrial signal to provide a combined terrestrial signal.

13. The method of claim 12, wherein the method further comprises the step of forward error correcting the combined satellite signal and separately forward error correcting the combined terrestrial signal.

14. The method of claim 13, wherein the method further comprises the step of comparing the signal quality of the forward error corrected combined satellite signal with the forward error corrected combined terrestrial signal to selectively choose an output among the forward error corrected combined satellite signal and the forward error corrected combined terrestrial signal.

15. The method of claim 9, wherein the step of combining is a switching step controlled by using the signal quality of the demodulated signals coming from at least two of the plurality of spatially diverse antennas.

16. A system for combining satellite and terrestrial signals from spatially diverse antennas, comprising:

a tuner for receiving a plurality of satellite signals and a terrestrial signal at a plurality of spatially diverse antennas;

at least a first analog to digital converter for converting at least one among the plurality of satellite signals and the terrestrial signal from an analog signal to a digital signal forming a first digital stream and for converting at least a second signal among the plurality of satellite signals and the terrestrial signal from an analog signal to a digital signal forming a second digital stream;

a switch arrangement for selectively switching among the first digital stream and the second digital stream before demodulating using a plurality of algorithms that selectively uses respectively demodulated signals of the first digital stream and the second digital stream to control the switch arrangement to provide a plurality of multiplexed signals; and

a combiner for combining the multiplexed signals to form a combined signal.

17. A system for combining satellite and terrestrial signals, comprising:

a tuner for receiving a plurality of satellite signals and at least one terrestrial signal using digital data streams from selectively chosen antennas among a plurality of spatially diverse antennas;

a signal quality analyzer for monitoring the plurality of satellite signals and at least one terrestrial signal using digital data streams from non-selected antennas among the plurality of spatially diverse antennas; and

a switch arrangement for selectively switching among several digital data streams from the plurality of spatially diverse antennas to enable processing of each of the plurality of satellite signals and the at least one terrestrial signal through the selectively chosen antennas and the non-selected antennas, wherein a selective switching decision is determined by a signal quality measurement comparison between a signal from a selectively chosen antenna and a signal from a non-selected antenna for each of the plurality of satellite signals and the at least one terrestrial signal.

18. A system of combining satellite and terrestrial signals, comprising:

a tuner for receiving a plurality of satellite signals and at least one terrestrial signal using a plurality of spatially diverse antennas;

at least one demodulator for demodulating the plurality of satellite signals and the at least one terrestrial signal to provide demodulated signals for each of at least two of the plurality of spatially diverse antennas for each of the plurality of satellite signals and the at least one terrestrial signal;

a signal quality analyzer for monitoring a signal quality of the demodulated signals coming from at least two of the plurality of spatially diverse antennas; and

a combiner for combining the demodulated signals coming from at least two of the plurality of spatially diverse antennas using the signal quality measured for each demodulated signal to provide a combined signal.