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 mult isensor 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 offers increased DS/SS signal dimensionality relative to the interferers. Interference mitigation through a spatio-temporal subspace projection techn ique 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 tra ding off the contribution of the spatial and time-frequency signatures to t he interference mitigation process. The expressions of the receiver signal- to-interference-noise ratio (SINR) implementing subspace projections are de rived, and numerical results are provided.