A method for receiving a signal, the signal comprising a useful signal, interfering signals and noise, and for suppressing interfering signals in a multi-channel receiver, comprising steps of:
- (a) reception, frequency transposition and digital conversion of the signal received over each of the channels of the multi-channel receiver, so as to obtain a digital multi-channel signal, this multi-channel signal corresponding to the sum of the useful signal, of the interfering signals and of the noise, the receiver comprising an antenna array that comprises a plurality of radiating elements, each of which corresponds to one channel of the multi-channel receiver, and that is defined by a complex vector function a(θ, ϕ) of two variables θ and ϕ defining a direction in space, comprising one component for each channel of the receiver and each component of which represents the amplitude and phase response of a respective channel of the receiver in the direction (θ, ϕ), the useful signal being defined by an unknown amplitude u[k] and by an unknown current direction (θu, ϕu), the interfering signals being defined by an unknown amplitude si[k] and by an unknown current direction (θu, ϕu), l representing the l-th interfering signal, the complex vector a(θu, ϕu), which is referred to as the current directional vector of the useful signal, comprising one component for each channel of the receiver, each component representing the amplitude and phase response of a respective channel of the receiver in the current arrival direction (θu, ϕu) of the useful signal, and, the complex vectors a(θil, ϕil), which are referred to as the current directional vectors of the interfering signals, each comprising one component for each channel of the receiver, each component representing the amplitude and phase response of a respective channel of the receiver in the current arrival direction (θil, ϕil) of the interfering signals;
- (b) estimation, from the digital multi-channel signal, of a correlation matrix {circumflex over (R)}x of the signals received over the channels of the receiver;
- (c) estimation of the variance of the noise, from the eigenvectors and eigenvalues of the correlation matrix {circumflex over (R)}x;
- (d) initial estimation of the arrival direction ({circumflex over (θ)}u, {circumflex over (ϕ)}u) of the useful signal and of the arrival direction ({circumflex over (θ)}il, {circumflex over (ϕ)}il) of the interfering signals from computation of the MUSIC spatial spectrum, then computation of assumed directional vectors {tilde over (a)}({circumflex over (θ)}u, {circumflex over (ϕ)}u) in the direction estimated for the useful signal and of assumed direction vectors {tilde over (a)}({circumflex over (θ)}il, {circumflex over (ϕ)}il) in the directions estimated for the interfering signals;
- (e) initializations:
- computation of a diagonal matrix the elements of which are the powers of the useful signal and of the interfering signals computed from the directional vectors estimated in step (d) and from the correlation matrix {circumflex over (R)}x;
- and
- computation of a complex diagonal matrix the elements of which represent the disparity between the current directional vectors and the directional vectors assumed in step (d), this matrix being called the amplitude/phase error matrix;
- (f) iterative computation:
- of a matrix of the current estimated directional vectors the elements of which are the product of the elements of the amplitude/phase error matrix and of the assumed directional vectors in the estimated directions;
- of the powers of the useful signals and of the interfering signals, from the matrix of the estimated current directional vectors;
- of the matrix of the amplitude/phase errors;
- and
- of the arrival direction ({circumflex over (θ)}u, {circumflex over (ϕ)}u) of the useful signal and of the arrival direction ({circumflex over (θ)}il, {circumflex over (ϕ)}il) of the interfering signals,
- the current directional vectors of the useful signal and of the interfering signals being computed, in a first iteration, with respect to the assumed directional vectors computed in step (d) and to the amplitude/phase errors initialized in step (e), then, for each of a plurality of following iterations, with respect to the directional vectors assumed and to the amplitude/phase errors computed in the preceding iteration, the number of iterations being predefined by the user;
- (g) reconstruction of the correlation matrix of the interfering signals and of the noise;
- (h) computation of a weighting matrix from the correlation matrix computed in step (g);
- and
- (i) suppression of the interfering signals from the signal received in step (a).