Bilinear signal synthesis in array processing

|Multiple source signals impinging on an antenna array can be separated by time-frequency synthesis techniques. Averaging of the time-frequency distributions of the data across the array permits the spatial signatures of sources to play a fundamental role in improving the synthesis performance. Array averaging introduces a weighing function in the time-frequency (t-f) domain that decreases the noise levels, reduces the interactions of the source signals, and mitigates the crossterms. This is achieved independent of the temporal characteristics of the source signals and without causing any smearing of the signal terms. The weighing function may take non-integer values, which are determined by the communication channel, the source positions and their angular separations. Unlike the recently devised blind source separation methods using spatial timefrequency distributions, the proposed method does not require whitening or retrieval of the source directional matrix. The paper evaluates the proposed method in terms of performance and computations relative to the existing source separation techniques based on quadratic t-f distributions. Keywords| Signal synthesis, time-frequency distribution, array processing, source separation.