Separation of communication signals in an adaptive antenna array

Claim 1

A method for separating m radio frequency signals incident on an array n antenna elements, wherein there is, for each element, a time-varying signal from the element and a corresponding input signal capable of being processed by the method, which input signal is generated from the time-varying signal and can be representative of its complex envelope, said method comprising: computing the weighted combination of the input signals for each set of weights in an ordered sequence of sets of weights, from a first set through an n-th set, with each of the resulting n computed combinations providing an output signal, designated with an index i as y i , and associated with the i-th set of weights; forming, for each one of the n output signals, a set of products of the one output signal and the complex conjugates of the input signals, and time smoothing each of said sets of products; for each of the n sets of smoothed products, modifying the i-th set of smoothed products associated with the i-th output signal, in response to all of the sets of weights which precede the i-th set of weights in said sequence; and for each of the n modified sets of smoothed products, normalizing the modified i-th set of smoothed products to provide the i-th set of weights, approaching that eigenvector of the cross-correlation matrix of the complex envelopes of said time-varying signals which corresponds to the -th largest eigenvalue of the matrix, whereby each of said output signals corresponds predominately to a different one of said incident radio frequency signals for m less than or equal to n.

Claim 2

A method for separating m radio frequency signals incident on an array n antenna elements, wherein there is, for each element, a time-varying signal from the element and a corresponding input signal capable of being processed by the method, which input signal is generated from the time-varying signal and can be representative of its complex envelope, said method comprising: computing the weighted combination of the input signals for each set of weights in an ordered sequence of sets of weights, from a first set through an n-th set, with each of the resulting n computed combinations providing an output signal, designated with an index i as y i , and associated with the i-th set of weights; forming, for each one of the n output signals, a set of products of the one output signal and the complex conjugates of the input signals, and time smoothing each of said sets of products; for each of the n sets of smoothed products, modifying the i-th set of smoothed products associated with the i-th output signal, in response to all of the sets of weights which precede the i-th set of weights in said sequence; and for each of the n modified sets of smoothed products, normalizing the modified i-th set of smoothed products to provide the i-th set of weights, approaching that eigenvector of the cross-correlation matrix of the complex envelopes of said time-varying signals which corresponds to the -th largest eigenvalue of the matrix, whereby each of said output signals corresponds predominately to a different one of said incident radio frequency signals for m less than or equal to n.

Claim 3

A method for separating m radiating signals incident on an array of n receiving elements, wherein there is, for each element, a time-varying signal derived from the element and a corresponding input signal capable of being processed by the method, which input signal is generated from the time-varying signal and can be representative of its complex envelope, said method comprising: computing the weighted combination of the input signals for each set of weights in ordered sequence of sets of weights, from a first set through an n-th set, with each of the resulting n computed combinations providing an output signal, designated with an index i as y i , and associated with the i-th set of weights; forming, for each one of the n output signals, a set of products of the one output signal and the complex conjugates of the input signals, and time smoothing each of said sets of products; for each of the n sets of smoothed products, modifying the i-th set of smoothed products associated with the i-th input signal, in response to all of the sets of weights which precede the i-th set of weights in said sequence; and for each of the n modified sets of smoothed products, normalizing the modified i-th set of smoothed products to provide the i-th set of weights, approaching that eigenvector of the cross-correlation matrix of the complex envelopes of said time-varying signals which corresponds to the i-th largest eigenvalue of the matrix, whereby each of said output signals corresponds predominantly to a different one of said incident signals for m less than or equal to n.

Claim 4

A method for separating m radiating signals incident on an array of n receiving elements, wherein there is, for each element, a time-varying signal derived from the element and a corresponding input signal capable of being processed by the method, which input signal is generated from the time-varying signal and can be representative of its complex envelope, said method comprising: computing the weighted combination of the input signals for each set of weights in ordered sequence of sets of weights, from a first set through an n-th set, with each of the resulting n computed combinations providing an output signal, designated with an index i as y i , and associated with the i-th set of weights; forming, for each one of the n output signals, a set of products of the one output signal and the complex conjugates of the input signals, and time smoothing each of said sets of products; for each of the n sets of smoothed products, modifying the i-th set of smoothed products associated with the i-th input signal, in response to all of the sets of weights which precede the i-th set of weights in said sequence; and for each of the n modified sets of smoothed products, normalizing the modified i-th set of smoothed products to provide the i-th set of weights, approaching that eigenvector of the cross-correlation matrix of the complex envelopes of said time-varying signals which corresponds to the i-th largest eigenvalue of the matrix, whereby each of said output signals corresponds predominantly to a different one of said incident signals for m less than or equal to n.

Claim 5

A method for separating m radio frequency signals incident on an array of n antenna elements, wherein there is, for each element, a time-varying signal derived from the element and a corresponding input signal capable of being processed by the method, which input signal is generated from the time-varying signal and can be representative of its complex envelope, said method comprising: multiplying a vector, which has as components the input signals, by each weighting vector in an ordered sequence of weighting vectors, from a first through an n-th weighting vector, with each of the resulting n products providing an output signal, designated with an index i as y i , and associated with the i-th weighting vector; forming, for each one of the n output signals, the product of the one output signal and a vector having as components the complex conjugates of the input signals, and time smoothing each of the resulting n product vectors; for each of the n smoothed product vectors, modifying the i-th smoothed product vector associated with the i-th output signal, in response to all of the weighting vectors which precede the i-th weighting vector in said sequence; and for each of the n modified smoothed product vectors, normalizing the modified i-th smoothed product vector to provide the i-th weighting vector, approaching that eigenvector of the cross-correlation matrix of the complex envelopes of said time-varying signals which corresponds to the i-th eigenvalue of the matrix, whereby each of said output signals corresponds predominantly to a different one of said incident signals for m less than or equal to n.

Claim 6

A method for separating m radio frequency signals incident on an array of n antenna elements, wherein there is, for each element, a time-varying signal derived from the element and a corresponding input signal capable of being processed by the method, which input signal is generated from the time-varying signal and can be representative of its complex envelope, said method comprising: multiplying a vector, which has as components the input signals, by each weighting vector in an ordered sequence of weighting vectors, from a first through an n-th weighting vector, with each of the resulting n products providing an output signal, designated with an index i as y i , and associated with the i-th weighting vector; forming, for each one of the n output signals, the product of the one output signal and a vector having as components the complex conjugates of the input signals, and time smoothing each of the resulting n product vectors; for each of the n smoothed product vectors, modifying the i-th smoothed product vector associated with the i-th output signal, in response to all of the weighting vectors which precede the i-th weighting vector in said sequence; and for each of the n modified smoothed product vectors, normalizing the modified i-th smoothed product vector to provide the i-th weighting vector, approaching that eigenvector of the cross-correlation matrix of the complex envelopes of said time-varying signals which corresponds to the i-th eigenvalue of the matrix, whereby each of said output signals corresponds predominantly to a different one of said incident signals for m less than or equal to n.

Claim 7

A method for separating m radiating signals incident on an array of n receiving elements, wherein there is, for each element, a time-varying signal derived from the element and a corresponding input signal capable of being processed by the method, which input signal is generated from the time-varying signal and can be representative of its complex envelope, said method comprising: multiplying a vector, which has as components the input signals, by each weighting vector in an ordered sequence of weighting vectors, from a first through an n-th weighting vector, with each of the resulting n products providing an output signal, designated with an index i as y i , and associated with the i-th weighting vector; forming, for each one of the n output signals, the product of the one output signal and a vector having as components the complex conjugates of the input signals, and time smoothing each of the resulting n product vectors; for each of the n smoothed product vectors, modifying the i-th smoothed product vector associated with the i-th output signal, in response to all of the weighting factors which precede the i-th weighting vector in said sequence; and for each of the n modified smoothed product vectors, normalizing the modified i-th smoothed product vector to provide the i-th weighting vector, approaching that eigenvector of the cross-correlation matrix of the complex envelopes of said time-varying signals which corresponds to the i-th largest eigenvalue of the matrix, whereby each of said output signals corresponds predominantly to a different one of said incident signals for m less than or equal to n.

Claim 8

A method for separating m radiating signals incident on an array of n receiving elements, wherein there is, for each element, a time-varying signal derived from the element and a corresponding input signal capable of being processed by the method, which input signal is generated from the time-varying signal and can be representative of its complex envelope, said method comprising: multiplying a vector, which has as components the input signals, by each weighting vector in an ordered sequence of weighting vectors, from a first through an n-th weighting vector, with each of the resulting n products providing an output signal, designated with an index i as y i , and associated with the i-th weighting vector; forming, for each one of the n output signals, the product of the one output signal and a vector having as components the complex conjugates of the input signals, and time smoothing each of the resulting n product vectors; for each of the n smoothed product vectors, modifying the i-th smoothed product vector associated with the i-th output signal, in response to all of the weighting factors which precede the i-th weighting vector in said sequence; and for each of the n modified smoothed product vectors, normalizing the modified i-th smoothed product vector to provide the i-th weighting vector, approaching that eigenvector of the cross-correlation matrix of the complex envelopes of said time-varying signals which corresponds to the i-th largest eigenvalue of the matrix, whereby each of said output signals corresponds predominantly to a different one of said incident signals for m less than or equal to n.

Claim 11

The method of claims 1 or 2, wherein the step of computing the weighted combination includes analog mixing said each set of weights and the input signals, and summing and band-pass filtering the results of the mixing at a sum frequency thereof.

Claim 12

The method of claims 1 or 2, wherein the steps of forming a set of products and time smoothing include analog mixing the input signals and said one output signal, and band-pass filtering the results of the mixing at a difference frequency thereof.

Claim 14

An apparatus for separating m radio frequency signals incident on an array of n antenna elements, wherein there is, for each element, a time-varying signal derived from the element and a corresponding input signal capable of being processed by the apparatus, which input signal is generated from the time-varying signal and can be representative of its complex envelope, said apparatus comprising: means for computing the weighted combination of the input signals for each set of weights in an ordered sequence of sets of weights, from a first set through an n-th set, with each of the resulting n computed combinations providing an output signal, designated with an index i as y i , and associated with the i-th set of weights; means for forming, for each one of the n output signals, a set of products of the one output signal and the complex conjugates of the input signals, and time smoothing each of said sets of products; means, for each of the n sets of smoothed products, for modifying the i-th set of smoothed products associated with the i-th output signal, in response to all of the sets of weigths which precede the i-th set of weights in said sequence; and means, for each of the n modified sets of smoothed products, for normalizing the modified i-th set of smoothed products to provide the i-th set of weights, approaching that eigenvector of the cross-correlation matrix of the complex envelopes of said time-varying signals which corresponds to the i-th largest eigenvalue of the matrix, whereby each of said output signals corresponds predominantly to a different one of said input signals for m less than or equal to n.

Claim 15

An apparatus for separating m radio frequency signals incident on an array of n antenna elements, wherein there is, for each element, a time-varying signal derived from the element and a corresponding input signal capable of being processed by the apparatus, which input signal is generated from the time-varying signal and can be representative of its complex envelope, said apparatus comprising: means for computing the weighted combination of the input signals for each set of weights in an ordered sequence of sets of weights, from a first set through an n-th set, with each of the resulting n computed combinations providing an output signal, designated with an index i as y i , and associated with the i-th set of weights; means for forming, for each one of the n output signals, a set of products of the one output signal and the complex conjugates of the input signals, and time smoothing each of said sets of products; means, for each of the n sets of smoothed products, for modifying the i-th set of smoothed products associated with the i-th output signal, in response to all of the sets of weigths which precede the i-th set of weights in said sequence; and means, for each of the n modified sets of smoothed products, for normalizing the modified i-th set of smoothed products to provide the i-th set of weights, approaching that eigenvector of the cross-correlation matrix of the complex envelopes of said time-varying signals which corresponds to the i-th largest eigenvalue of the matrix, whereby each of said output signals corresponds predominantly to a different one of said input signals for m less than or equal to n.

Claim 16

An apparatus for separating m radiating signals incident on an array of n receiving elements, wherein there is, for each element, a time-varying signal derived from the element and a corresponding input signal capable of being processed by the apparatus, which input signal is generated from the time-varying signal and can be representative of, its complex envelope, said apparatus comprising: means for computing the weighted combination of the input signals for each set of weights in an ordered sequence of sets of weights, from a first set through an n-th set, with each of the resulting n computed combinations providing an output signal, designated with an index i as y i , and associated with the i-th set of weights; means for forming, for each one of the n output signals, a set of products of the one output signal and the complex conjugates of the input signals, and time smoothing each of said sets of products; means, for each of the n sets of smoothed products, for modifying the i-th set of smoothed products associated with the i-th output signal, in response to all of the sets of weights which precede the i-th set of weights in said sequence; and means, for each of the n modified sets of smoothed products, for normalizing the modified i-th set of smoothed products to provide the i-th set of weights, approaching that eigenvector of the cross-correlation matrix of the complex envelopes of said time-varying signals which corresponds to the i-th largest eigenvalue of the matrix, whereby each of said output signals corresponds to a different one of said input signals for m less than or equal to n.

Claim 17

An apparatus for separating m radiating signals incident on an array of n receiving elements, wherein there is, for each element, a time-varying signal derived from the element and a corresponding input signal capable of being processed by the apparatus, which input signal is generated from the time-varying signal and can be representative of, its complex envelope, said apparatus comprising: means for computing the weighted combination of the input signals for each set of weights in an ordered sequence of sets of weights, from a first set through an n-th set, with each of the resulting n computed combinations providing an output signal, designated with an index i as y i , and associated with the i-th set of weights; means for forming, for each one of the n output signals, a set of products of the one output signal and the complex conjugates of the input signals, and time smoothing each of said sets of products; means, for each of the n sets of smoothed products, for modifying the i-th set of smoothed products associated with the i-th output signal, in response to all of the sets of weights which precede the i-th set of weights in said sequence; and means, for each of the n modified sets of smoothed products, for normalizing the modified i-th set of smoothed products to provide the i-th set of weights, approaching that eigenvector of the cross-correlation matrix of the complex envelopes of said time-varying signals which corresponds to the i-th largest eigenvalue of the matrix, whereby each of said output signals corresponds to a different one of said input signals for m less than or equal to n.