Array processing for nonstationary interference suppression in DS/SS communications using subspace projection techniques

| Combined spatial and time-frequency signatures of signal arrivals at a multi-sensor array are used for nonstationary interference suppression in direct-sequence spread-spectrum (DS/SS) communications. With random PN spreading code and deterministic nonstationary interferers, the use of antenna arrays o ers increased DS/SS signal dimensionality relative to the interferers. Interference mitigation through spatio-temporal subspace projection technique leads to reduced DS/SS signal distortion and improved performance over the case of a single antenna receiver. The angular separation between the interference and desired signals is shown to play a fundamental role in trading o the contribution of the spatial and time-frequency signatures to the interference mitigation process. The expressions of the receiver SINR implementing subspace projections are derived and numerical results are provided. Keywords|Time-frequency distribution, interference suppression, subspace projection, array processing, directsequence spread-spectrum communication.