Method and apparatus for multiplex binary data communication
First Claim
1. A data communication system for transmitting binary information wherein each information bit is represented by a signal of a first value or a signal of a second value, said system comprising:
- a transmitter means, said transmitter means comprising at least first and second communicator means, each of said communicator means including means for emitting a series of information bits represented by said signals, at least first and second modulator means, said first and second modulator means generating first and second modulation signals sets, respectively, said modulation signal sets being linearly independent, said first communicator means being connected to said first modulator means whereby said first modulator means emits a first modulated signal, said second communicator means being connected to said second modulator means whereby said second modulator means emits a second modulated signal;
a common transmitter means for transferring said modulated signals from said transmission means to a point remote therefrom;
a receiver means comprising first and second correlator means having inputs for receiving the modulated signals received from said common transmission means, said first correlator means including means for correlating all received modulated signals with a signal uniquely related to said first modulation signal set and emitting first correlated signals, said second correlator means including means for correlating all received modulated signals with another signal uniquely related to said second modulation signal set and emitting second correlated signals, and processor means connected to said correlator means for interactively processing the first and second correlated signals and emitting first output signals having one of two binary values in accordance with the polarity of the first correlated signals emitted from said first correlator means and for emitting second output signals having one of said two binary values in accordance with the polarity of the second correlated signals emitted from said second correlator means.
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Abstract
In electromagnetic communication different data streams share a common communication medium by being multiplexed. Each individual data stream employs its own unique modulation waveform set. A receiver for a given data stream comprises correlators for the waveforms in the corresponding modulation waveform set. If the waveforms in all the different modulation waveform sets are not orthogonal, then the output of correlators at a given receiver will not only contain the desired information components of the data stream to which they are matched but also components from the other data streams. This is termed cross-talk. Processors are provided which are responsive to the outputs of all waveform correlators. They provide a means for detecting the original data stream information in the presence of cross-talk. When there is no noise in the communication transmission the processors cancel the cross-talk.
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Citations
26 Claims
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1. A data communication system for transmitting binary information wherein each information bit is represented by a signal of a first value or a signal of a second value, said system comprising:
- a transmitter means, said transmitter means comprising at least first and second communicator means, each of said communicator means including means for emitting a series of information bits represented by said signals, at least first and second modulator means, said first and second modulator means generating first and second modulation signals sets, respectively, said modulation signal sets being linearly independent, said first communicator means being connected to said first modulator means whereby said first modulator means emits a first modulated signal, said second communicator means being connected to said second modulator means whereby said second modulator means emits a second modulated signal;
a common transmitter means for transferring said modulated signals from said transmission means to a point remote therefrom;
a receiver means comprising first and second correlator means having inputs for receiving the modulated signals received from said common transmission means, said first correlator means including means for correlating all received modulated signals with a signal uniquely related to said first modulation signal set and emitting first correlated signals, said second correlator means including means for correlating all received modulated signals with another signal uniquely related to said second modulation signal set and emitting second correlated signals, and processor means connected to said correlator means for interactively processing the first and second correlated signals and emitting first output signals having one of two binary values in accordance with the polarity of the first correlated signals emitted from said first correlator means and for emitting second output signals having one of said two binary values in accordance with the polarity of the second correlated signals emitted from said second correlator means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
- a transmitter means, said transmitter means comprising at least first and second communicator means, each of said communicator means including means for emitting a series of information bits represented by said signals, at least first and second modulator means, said first and second modulator means generating first and second modulation signals sets, respectively, said modulation signal sets being linearly independent, said first communicator means being connected to said first modulator means whereby said first modulator means emits a first modulated signal, said second communicator means being connected to said second modulator means whereby said second modulator means emits a second modulated signal;
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10. A data communication system for transmitting binary information wherein each information bit is represented by a signal of a first value or a signal of a second value, said system comprising:
- a transmitter means, said transmitter means comprising at least first and second communicator means, each of said communicator means including means for emitting a series of information bits, represented by said signals, at least first and second modulator means, said first and second modulator means generating first and second modulation signal sets, respectively, said modulation signals sets being linearly independent, said first communicator means being connected to said first modulator means whereby said first modulator means emits a first modulated signal, said second communicator means being connected to said second modulator means whereby said second modulator means emits a second modulated signal;
a common transmission means for transferring said modulated signals from said transmission means to a point remote therefrom;
a receiver means at said point, said receiver means comprising first and second correlator means having inputs for receiving the modulated signals received from said common transmission means, said first correlator means including means for correlating all received modulated signals with a signal uniquely related to said first modulation signal set and emitting first correlated signals, said second correlator means including means for correlating all received modulator signals with another signal uniquely related to said second modulation signal set and emitting second correlated signals, and processor means comprising means decoding convolutional codes connected to said correlator means for interactively processing the first and second correlated signals and emitting signals having one of two binary values in accordance with the signals received from said correlator means.
- a transmitter means, said transmitter means comprising at least first and second communicator means, each of said communicator means including means for emitting a series of information bits, represented by said signals, at least first and second modulator means, said first and second modulator means generating first and second modulation signal sets, respectively, said modulation signals sets being linearly independent, said first communicator means being connected to said first modulator means whereby said first modulator means emits a first modulated signal, said second communicator means being connected to said second modulator means whereby said second modulator means emits a second modulated signal;
- 11. In a data communication system wherein a plurality of communicators at a transmitter emit bits of information to respective modulators, each operating with a modulation signal, which transmit bit-modulated signals to a plurality of users, each associated with a definite communicator at a receiver over a common transmission medium, the modulation signals being mutually linearly independent, the method of signal processing comprising the steps of first sequentially transmitting from said transmitter to said receiver a modulation signal from each modulator, at the receiver storing a representation of each received modulation signal, and utilizing each stored representation to detect bits for the respective users in a stream of modulated signals.
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16. The method of transmitting binary data from a plurality of N communicators at a transmitter to a plurality of N users at a receiver simultaneously over a common channel comprising the steps of:
- each communicator generating a signal once per period of time T and in the form Xi (k), where i represents the ith bit in the stream occurring at a time (i-1)T, k represents a typical communicator and its associated user, Xi (k) having only either a first or a second binary value;
modulating a plurality of modulation signals in the form Sk (t) with the Xi (k) bits of the data streams to generate a plurality of modulated signals of the form
space="preserve" listing-type="equation">X.sub.i S.sub.k (t-(i-1)T),where Sk (t) is the modulation signal for said typical communicator;
transmitting over the common channel a signal in the form w(t), where w(t) represents the instantaneous sum of all of said modulated signals;
generating a plurality of signals of the form Sk *(t), where Sk *(t) is a representation of the modulation signal Sk (t) after transmission over the common channel;
correlating for each period of time T the signal of the form w(t) with each of the representations of the modulation signals Sk *(t) to produce signals of the form ##EQU9## where Δ
is the time for signals to travel over the common channel; and
interactively processing each of said Yi *(k) signals to produce signals of the form ##EQU10## Vkj is a numerical coefficient derived from correlations of the signals of the form Sk *(t). - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
- each communicator generating a signal once per period of time T and in the form Xi (k), where i represents the ith bit in the stream occurring at a time (i-1)T, k represents a typical communicator and its associated user, Xi (k) having only either a first or a second binary value;
Specification