Multichannel constant envelope orthogonal waveforms using receiver design

1. An apparatus comprising

a first transmitter having a computer processor and a first transmission output;

a second transmitter having a computer processor and a second transmission output;

a first receiver having an input port, an output port, a control input, and a computer processor;

a second receiver having an input port, an output port, a control input, and a computer processor;

a control device having computer memory and a computer processor;

wherein the computer processor of the first transmitter is programmed to cause the first transmitter to transmit a first transmit signal through the airwaves from the first transmission output;

wherein the computer processor of the second transmitter is programmed to cause the second transmitter to transmit a second transmit signal through the airwaves from the second transmission output;

wherein the first transmit signal has a finite duration waveform and constant modulus in the time domain;

wherein the second transmit signal has a finite duration waveform and constant modulus in the time domain;

wherein the first transmit signal differs from the second transmit signal;

wherein the first transmission output is spaced apart from the second transmission output;

wherein characteristics of the first transmit signal and the second transmit signal are stored in computer memory of the control device;

wherein the computer processor of the control device is programmed to use both the characteristics of the first transmit signal and the second transmit signal to determine a first control signal;

wherein the computer processor of the control device is programmed to use both the characteristics of the first transmit signal and the second transmit signal to determine a second control signal;

wherein the computer processor of the control device is programmed to cause the first and second control signals to be supplied to the first receiver and the second receiver, respectively;

wherein the computer processor of the first receiver uses the first control signal to define an impulse response of the first receiver and to cause a first return signal received at an input port of the first receiver to be filtered and thereby modified into a first output signal at an output port of the first receiver;

wherein the first return signal has a component due to the first transmit signal transmitted through the airwaves and a component due to the second transmit signal transmitted through the airwaves, and the first receiver uses the first control signal to filter the first return signal into the first output signal, so that the first output signal contains a substantial part of the component due to the first transmit signal transmitted through the airwaves, and does not contain a substantial part of the component due to the second transmit signal transmitted through the airwaves;

wherein the computer processor of the second receiver uses the second control signal to define an impulse response of the second receiver and to cause a second return signal received at an input port of the second receiver to be filtered and thereby modified into a second output signal at an output port of the second receiver; and

wherein the second return signal has a component due to the first transmit signal transmitted through the airwaves and a component due to the second transmit signal transmitted through the airwaves, and the second receiver uses the second control signal to filter the second return signal into the second output signal, so that the second output signal contains a substantial part of the component due to the second transmit signal transmitted through the airwaves, and does not contain a substantial part of the component due to the first transmit signal transmitted through the airwaves.

2. The apparatus of claim 1

wherein the first and second control signals programmed by the computer processor of the control device are determined as follows

the first control signal, which is h 1 (n), n=1, 2, . . . N and the second control signal, which is h 2 (n), n=1, 2, . . . N are defined by the equation:

h i =[h i (1), h i (2), . . . h i ( K )], i= 1→2

and

h i =A i −1 b * n o , i= 1, 2

wherein n represents the time-index sampled at a constant sampling rate A i −1 is the inverse of the matrix A i defined by:

A i =F* i,0 F i,0 +ΣF* j F j >0

wherein A i represents a K×K positive-definite matrix, and F i represents the (N+K−1)×K matrix

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 generated from the i th input sequence, for the ith transmit signal from the ith transmitter x i ;

wherein F i, 0 represents the (N+K−2)×K matrix generated from F i with its n o row deleted;

Wherein

b n o represents the row vector correspond to the n o row of F i , which is

b n o =[0, . . . 0, x i ( N ), x i ( N− 1), . . . x i (1), 0, . . . 0]

 for n o >N.

3. A method comprising

transmitting a first transmit signal through the airwaves from a first transmission output of a first transmitter;

transmitting a second transmit signal through the airwaves from a second transmission output of a second transmitter;

wherein the first transmit signal has a finite duration waveform and constant modulus in the time domain;

wherein the second transmit signal has a finite duration waveform and constant modulus in the time domain;

wherein the first transmit signal differs from the second transmit signal;

wherein the first transmission output is spaced apart from the second transmission output;

further comprising storing characteristics of the first transmit signal and the second transmit signal in computer memory of a control device;

using a computer processor to use both characteristics of the first transmit signal and of the second transmit signal to determine a first control signal;

using a computer processor to use both characteristics of the first transmit signal and of the second transmit signal to determine a second control signal;

supplying the first and second control signals to a first receiver and a second receiver, respectively;

using the first control signal to define an impulse response of the first receiver and to cause a first return signal received at an input port of the first receiver to be filtered and thereby modified into a first output signal at an output port of the first receiver;

wherein the first return signal has a component due to the first transmit signal transmitted through the airwaves and a component due to the second transmit signal transmitted through the airwaves, and the first receiver uses the first control signal to filter the first return signal into the first output signal, so that the first output signal contains a substantial part of the component due to the first transmit signal transmitted through the airwaves, and does not contain a substantial part of the component due to the second transmit signal transmitted through the airwaves;

using the second control signal to define an impulse response of the second receiver and to cause a second return signal received at an input port of the second receiver to be filtered and thereby modified into a second output signal at an output port of the second receiver; and

wherein the second return signal has a component due to the first transmit signal transmitted through the airwaves and a component due to the second transmit signal transmitted through the airwaves, and the second receiver uses the second control signal to filter the second return signal into the second output signal, so that the second output signal contains a substantial part of the component due to the second transmit signal transmitted through the airwaves, and does not contain a substantial part of the component due to the first transmit signal transmitted through the airwaves.

4. The method of claim 3

wherein the first and second control signals are determined as follows

the first control signal, which is h 1 (n), n=1, 2, . . . N and the second control signal, which is h 2 (n), n=1, 2, . . . N are defined by the equation:

h i =[h i (1), h i (2), . . . h i ( K )], i= 1, 2

and

h i =A i −1 b * n o , i= 1, 2

wherein n represents the time-index sampled at a constant rate, A i −1 is the inverse of the matrix A i defined by:

A i =F* i,0 F i,0 +ΣF* j F j >0

wherein A i represents a K×K positive-definite matrix, and F i represents the (N+K−1)×K matrix

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 generated from the i th input sequence, for the ith transmit signal from the ith transmitter x i ;

wherein F i, 0 represents the (N+K−2)×K matrix generated from F i with its n o row deleted;

Wherein

b n o represents the row vector correspond to the n o row of F i , which is

b n o =[0, . . . 0, x i ( N ), x i ( N− 1), . . . x i (1), 0, . . . 0]

 for n o >N.