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

In smart antenna systems (SAS), the most compelling research work is the space-division multiple-access (SDMA) which includes uplink source separation and downlink selective transmission. 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 the spatial signature matrix (SS matrix), and estimates the multiuser spatial signature through the eigen-decomposition 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 the direction-of-arrival (DOA) of the correlated multiuser signals