Spatial averaging of time-frequency distributions for signal recovery in uniform linear arrays

This paper presents a new approach based on spatial:time-frequency averagin g for separating signals received by a uniform linear antenna array, In thi s approach, spatial averaging: of the time-frequency distributions (TFDs) o f the sensor data is performed at multiple time-frequency points. This aver aging restores the diagonal structure of the source TFD matrix necessary fo r source separation. With spatial averaging, crossterms move from their off -diagonal positions in the source TFD:matrix to become part of the matrix d iagonal entries. It is shown that the proposed approach yields improved per formance over the case when no spatial averaging is performed. Further, we demonstrate that in the context of source separation, the spatially a avera ged Wigner-Ville distribution outperforms the combined spatial-time-frequen cy averaged distributions, such as the one obtained by using the Choi-Willi ams distribution. Simulation examples involving the separation of two sourc es with close AM and FM modulations are presented.