US 2002/0057745 A1 · System and method for combining multiple satellite channels into a virtual composite channel

Abstract

A satellite communications system provides an information channel between remotely located transmitters and receivers A virtual satellite system provides the same service, but divides the signal either in power or in data content into subchannels such that any particular signal is conducted to the intended receiver via a plurality of traditional satellite channels. The receiving terminal accepts the plurality of signals simultaneously from a possible plurality of satellites, combining the subchannels comprising the virtual channel into the original signal content as if conducted via a single channel. The receiving antenna system receives satellite subchannel signals from a plurality of directions using multiple antennas or a single antenna with multi-direction capability. Prior to signal combining, the receiver necessarily time-synchronizes the plurality of subchannels by introducing time delay in some channels before combining the subsignals into the original composite. A timing signal present in the virtual satellite system assists the receiver in determining the amount of delay to apply to each incoming signal. The timing signal is either a separate carrier or an additional modulation on the existing information-bearing carrier.

Claims36

Dependent claims

A multi-channel satellite uplink transmission system dividing an original digital signal into a plurality of digital subchannels and adding a common timing signal to each subchannel, the multi-channel uplink transmission system comprising:

a subchannel divider for transforming the original digital signal into the plurality of digital subchannel signals such that each digital subchannel signal contains at least some information unique to that subchannel signal and also such that a bit rate of each digital subchannel signal is lower than a bit rate of the original digital signal;
a timing generator for generating a periodic signal;
signal combining means, coupled to the timing generator and the subchannel divider, for adding the periodic signal to each subchannel signal within a bandwidth of each subchannel signal such that no additional bandwidth allocation is required to transmit the periodic signal, and in accordance therewith generating a plurality of modulated carrier signals;
upconverting means, coupled to the signal combining means, for translating a frequency of each modulated carrier signal to a frequency of a selected one of a plurality of satellite transponders;
amplifier means, coupled to the upconverting means, for increasing a power level of each translated modulated carrier signal;
and
antenna means, coupled to the amplifier means, for directing a radio frequency wave corresponding to each translated modulated carrier signal toward a receiving antenna of each selected satellite transponder.

4 more elements

A receiving terminal system collecting signals from a plurality of satellite transponders and creating a delayed reconstruction of an original digital signal, the receiving terminal system comprising:

one of:
a multiple beam antenna simultaneously receiving the signals from the plurality of transponders and presenting each of said signals on a corresponding one of a plurality of separate output ports;
and
a plurality of independent single beam antennas simultaneously receiving the signals from the plurality of transponders and presenting each of said signals on said corresponding one of said plurality of separate output ports;
a plurality of tuners, each coupled to each separate output port, for translating a frequency of each received signal to a fixed intermediate frequency;
a plurality of demodulators, each coupled to each tuner, for demodulating each tuner output and creating a plurality of bit streams each corresponding to an information content of an associated subchannel;
a plurality of delay means, each coupled to a demodulator output, for delaying one or more first-arriving of the plurality of bit streams such that outputs of the plurality of delay means are synchronized in time;
a digital combiner, coupled to the outputs of the plurality of delay means, for combining information in each of the outputs of the plurality of delay means into the delayed reconstruction of the original digital signal;
a timing signal correlator, coupled to each tuner output, for measuring a relative delay between each received signal and in accordance therewith generating a timing signal correlation signal;
a nonvolatile memory for storing information about a frequency property and a propagation delay property of each of a plurality of virtual channels to be selected, and in accordance therewith generating a plurality of nonvolatile memory signals;
and
a controller, coupled to the one of the multiple beam antenna and the plurality of independent single beam antennas, the plurality of tuners, the plurality of delay means, the timing signal correlator, and the nonvolatile memory, for receiving the timing signal correlation signal and the nonvolatile memory signals and issuing a plurality of control signals to the one of the multiple beam antenna and the plurality of independent single beam antennas setting a beam direction and a polarization, a plurality of tuner control signals to the plurality of tuners to set a plurality of subchannel receive frequencies, and a plurality of delay control signals to the plurality of delay means to synchronize the outputs of the delay means.

9 more elements

A multi-channel satellite uplink transmission system dividing an original digital signal into a plurality of digital subchannel signals and adding a common timing signal to each subchannel, the multi-channel uplink transmission system comprising:

a subchannel divider for transforming the original digital signal into the plurality of digital subchannel signals such that each digital subchannel signal carries identical information at a same bit rate as the original digital signal;
a timing generator for generating a periodic signal,
signal combining means, coupled to the timing generator and the subchannel divider, for adding the periodic signal to each subchannel signal within a bandwidth of each subchannel signal such that no additional bandwidth allocation is required to transmit the periodic signal, and in accordance therewith generating a plurality of modulated carrier signals;
upconverting means, coupled to the signal combining means, for translating a frequency of each modulated carrier signal to a frequency of a selected one of a plurality of satellite transponders;
amplifier means, coupled to the upconverting means, for increasing a power level of each translated modulated carrier signal;
and
antenna means, coupled to the amplifier means, for directing a radio frequency wave corresponding to each translated modulated carrier signal toward a receiving antenna of each selected satellite transponder.

4 more elements

one of:
a multiple beam antenna simultaneously receiving the signals from the plurality of satellite transponders and presenting each of said signals on a corresponding one of a plurality of separate output ports;
and
a plurality of independent single beam antennas simultaneously receiving the signals from the plurality of transponders and presenting each of said signals on said corresponding one of said plurality of separate output ports;
a plurality of tuners, each coupled to each separate output port, for translating a frequency of each received signal to a fixed intermediate frequency;
a plurality of demodulators, each coupled to each tuner, for demodulating each tuner output and each creating one of a plurality of streams of soft decisions in the form of digitized decision-confidence-values corresponding to an associated subchannel;
a plurality of delay means, each coupled to a demodulator output, for delaying one or more first-arriving of the streams of soft decisions such that the streams of soft decisions output from the plurality of delay means are synchronized in time;
a digital combiner, coupled to the outputs of the plurality of delay means, for combining soft decisions from all subchannels received into a delayed reconstruction of the original digital signal;
a timing signal correlator, coupled to each tuner output, for measuring a relative delay between arriving subchannel signals, and in accordance therewith generating a timing signal correlation signal;
a nonvolatile memory for storing information about a frequency property and a propagation delay property of a plurality of virtual channels to be selected, and in accordance therewith generating a plurality of nonvolatile memory signals;
and
a controller, coupled to the one of the multiple beam antenna and the plurality of independent single beam antennas, the plurality of tuners, the plurality of delay means, the timing signal correlator, and the nonvolatile memory, for receiving the timing signal correlation signal and the nonvolatile memory signals and issuing control signals to the one of the multiple beam antenna and the plurality of independent single beam antennas setting a beam direction and a polarization, a plurality of tuner control signals to the tuners to set a plurality of subchannel receive frequencies, and a plurality of delay control signals to the plurality of delay means to synchronize the outputs of the delay means.

9 more elements

A receiving terminal system collecting analog signals from a plurality of satellite transponders and creating a delayed reconstruction of an original analog signal, the receiving terminal system comprising:

one of:
a multiple beam antenna simultaneously receiving the analog signals from the plurality of satellite transponders and presenting each of said analog signals on a corresponding one of a plurality of separate output ports;
and
a plurality of independent single beam antennas simultaneously receiving the analog signals from the plurality of satellite transponders and presenting each of said analog signals on the corresponding one of the plurality of separate output ports;
a plurality of tuners, each coupled to each separate output port, for translating a frequency of each received analog signal to a fixed intermediate frequency;
a plurality of demodulators, each coupled to each tuner, for demodulating each tuner output and each creating one of the analog signals corresponding to an information content of an associated subchannel;
a plurality of delay means, each coupled to a demodulator output, for delaying one or more first-arriving of the subchannel signals such that outputs of the plurality of delay means are synchronized in time;
an analog combiner, coupled to the outputs of the plurality of delay means, for combining information in each of the subchannels into the delayed reconstruction of the original analog signal;
a timing signal correlator, coupled to each of the plurality of tuners, for measuring a relative delay between arriving subchannel signals, and in accordance therewith generating a timing signal correlation signal;
a nonvolatile memory for storing information about a frequency property and a propagation delay property of a plurality of virtual channels to be selected, and in accordance therewith generating a plurality of nonvolatile memory signals;
and
a controller, coupled to the one of the multiple beam antenna and the plurality of independent single beam antennas, the plurality of tuners, the plurality of delay means, the timing signal correlator, and the nonvolatile memory, for receiving the timing signal correlation signal and the nonvolatile memory signals and issuing control signals to the one of the multiple beam antenna and the plurality of independent single beam antennas setting a beam direction and a polarization, a plurality of tuner control signals to the tuners to set a plurality of subchannel receive frequencies, and a plurality of delay control signals to the plurality of delay means to synchronize the outputs of the delay means.

9 more elements

Dependencies are inferred from the claim text.

System and method for combining multiple satellite channels into a virtual composite channel

Life of this patent

System and method for combining multiple satellite channels into a virtual composite channel

Life of this patent

Abstract

Claims36