Digital broadcast system using satellite direct broadcast and terrestrial repeater
First Claim
1. A method for converting a time division multiplexed bit stream into a plurality of multicarrier modulated signals at a terrestrial repeater, comprising the steps of:
- receiving said time division multiplexed bit stream from a satellite;
dividing said time division multiplexed bit stream into a plurality of parallel bit paths;
representing each of a predetermined number of bits in each of said plurality of bit paths as a symbol comprising an imaginary component and a real component;
providing said symbols to parallel inputs of an inverse Fourier transform converter as complex number frequency coefficient inputs to generate outputs which comprise modulated, narrow-band, orthogonal carriers; and
transmitting said modulated, narrow-band, orthogonal carriers from said terrestrial repeater.
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Accused Products
Abstract
A digital broadcast system is provided which uses a satellite direct radio broadcast system having different downlink modulation options in combination with a terrestrial repeater network employing different re-broadcasting modulation options to achieve high availability reception by mobile radios (14), static radios and portable radios (14) in urban areas, suburban metropolitan areas, and rural areas, including geographically open areas and geographic areas characterized by high terrain elevations. Two-arm and three-arm receivers are provided which each comprise a combined architecture for receiving both satellite and terrestrial signals, and for maximum likelihood combining of received signals for diversity purposes. A terrestrial repeater is provided for reformatting a TDM satellite signal as a multicarrier modulated terrestrial signal. Configurations for indoor and outdoor terrestrial repeaters are also provided.
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Citations
26 Claims
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1. A method for converting a time division multiplexed bit stream into a plurality of multicarrier modulated signals at a terrestrial repeater, comprising the steps of:
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receiving said time division multiplexed bit stream from a satellite; dividing said time division multiplexed bit stream into a plurality of parallel bit paths; representing each of a predetermined number of bits in each of said plurality of bit paths as a symbol comprising an imaginary component and a real component; providing said symbols to parallel inputs of an inverse Fourier transform converter as complex number frequency coefficient inputs to generate outputs which comprise modulated, narrow-band, orthogonal carriers; and transmitting said modulated, narrow-band, orthogonal carriers from said terrestrial repeater. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A receiver for receiving a broadcast signal in a combined satellite and terrestrial digital broadcasting system, comprising:
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a first receiver arm for receiving a first satellite signal transmitted from a first satellite on a first carrier frequency, said first satellite signal comprising said broadcast signal and being modulated in accordance with at least one of time division multiplexing and code division multiplexing, said first receiver arm comprising a demodulator for recovering said broadcast signal; a second receiver arm for receiving a terrestrial signal transmitted from a terrestrial station on a second carrier frequency, said terrestrial signal comprising said broadcast signal and being modulated in accordance with at least one of adaptive equalized time division multiplexing, coherent frequency hopping adaptive equalized time division multiplexing, code division multiplexing and multicarrier modulation, said second receiver arm comprising a demodulator for recovering said broadcast signal; and a combiner for generating an output signal from at least one of said first satellite signal and said terrestrial signal. - View Dependent Claims (10)
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11. A method of transmitting a broadcast signal to a radio receiver, comprising the steps of:
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modulating said broadcast signal for transmission to said radio receiver as a first signal in accordance with at least one of time division multiplexing and code division multiplexing; transmitting said first signal to said radio receiver from a first satellite on a first carrier frequency; modulating said broadcast signal at a terrestrial station for transmission to said radio receiver as a second signal in accordance with at least one of adaptive equalized time division multiplexing, coherent frequency hopping adaptive equalized time division multiplexing, code division multiplexing, and multicarrier modulation; and transmitting said second signal to said radio receiver from said terrestrial station on a second carrier frequency that is different from said first carrier frequency. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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19. A digital broadcasting system for transmitting a broadcast signal, said broadcast signal being transmitted from an earth station, comprising:
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a satellite for receiving said broadcast signal from said earth station and for transmitting a satellite signal comprising said broadcast signal on a first carrier frequency; and a terrestrial repeater for receiving said satellite signal and for generating and transmitting a terrestrial signal from said satellite signal comprising said broadcast signal on a second carrier frequency that is different from said first carrier frequency, said terrestrial signal being modulated by said terrestrial repeater in accordance with a multipath-tolerant modulation technique; wherein said terrestrial repeater is operable to modulate said terrestrial signal using multicarrier modulation; and said terrestrial repeater to operable to receive said satellite signal and to demodulate said satellite signal into a baseband signal prior to modulating said baseband signal using multicarrier modulation.
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20. A digital broadcasting system for transmitting a broadcast signal, said broadcast signal being transmitted from an earth station, comprising:
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a satellite for receiving said broadcast signal from said earth station and for transmitting a satellite signal comprising said broadcast signal on a first carrier frequency; a terrestrial repeater for receiving said satellite signal and for generating and transmitting a terrestrial signal from said satellite signal comprising said broadcast signal on a second carrier frequency that is different from said first carrier frequency, said terrestrial signal being modulated by said terrestrial repeater in accordance with a multipath-tolerant modulation technique; and a second satellite operable to receive said broadcast program from said earth station and to transmit a second satellite signal comprising said broadcast signal on said first carrier frequency and delayed a predetermined period of time with respect to the transmission of the first satellite signal.
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21. A terrestrial repeater for retransmitting satellite signals to radio receivers, comprising:
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a terrestrial receiver for receiving said satellite signals; and a terrestrial waveform modulator for generating terrestrial signals from said satellite signals, said terrestrial signals being modulated by said terrestrial waveform modulator in accordance with multicarrier modulation; wherein said satellite signals are transmitted from a satellite using a first carrier frequency, and said terrestrial waveform modulator is operable to transmit said terrestrial signals to said radio receivers using a second carrier frequency that is different from said first carrier frequency; and wherein said terrestrial waveform modulator comprises a time division demultiplexer for demultiplexing said satellite signals from a serial time division multiplexed bit stream into a plurality of parallel bit streams; and an inverse fast Fourier transform device for generating a digital analog signal comprising a plurality of discrete Fourier transform coefficients.
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22. A digital broadcasting system for transmitting a broadcast signal, said broadcast signal being transmitted from an earth station, comprising:
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a first satellite configured to receive said broadcast program from said earth station and to transmit a time division multiplexed satellite signal comprising said broadcast signal; a terrestrial repeater configured to receive said satellite signal and to generate and transmit a terrestrial signal from said satellite signal comprising said broadcast signal, said terrestrial signal being modulated by said terrestrial repeater in accordance with at least one of adaptive equalized time division multiplexing, coherent frequency hopping adaptive equalized time division multiplexing, code division multiplexing and multicarrier modulation; and at least one radio receiver configured to receive said satellite signal and said terrestrial signal, said radio receiver comprising a diversity combiner for generating an output signal from at least one of said satellite signal and said terrestrial signal. - View Dependent Claims (23, 24, 25, 26)
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Specification