Spatial signature estimation in cyclic cumulant domain and multiuser signal separation in uplink SDMA

In smart antenna system (SAS), the most compelling research work is the space-division multiple-access (SDMA) which includes uplink source separation and downlink selective transmission. In this paper, we propose a subspace-based spatial signature estimation algorithm of cochannel multiuser signals by jointly exploiting cumulant and cyclostationarity, and apply it to multiuser signal copy in uplink SDMA. Our method constructs a new matrix called spatial signature matrix (SS Matrix), and estimates multiuser spatial signature through the eigendecomposition of the SS Matrix. Based on estimated spatial signature, a spatial filter bank is designed for cochannel multiuser waveform estimation. Computer simulations show that the spatial response of the filter bank can be used to find direction-of-arrival (DOA) of the correlated multiuser signals.