User Detection In MIMO-OFDM System For Multiple Accesses

The proposed a new method for signal recovery in multiuser multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) system with known partial channel state information. The dispersive channel in multiuser MIMO_OFDM system can be seen as set of instantaneous mixtures for the perspective of frequency bin (FB). When a new user arrives, the new interferences are introduced making an expanding mixture. The channel state information (CSI) is estimated with pilot symbols, recovering the transmitted signals. However, if the new user’s CSI is known, it can be used to recover the transmitted signals, instead of the bandwidth waste pilot symbols. In the proposed method, from the second order statistics of the received signals, the parameters of the mixture caused by new user are extracted. Then the signals belong to different users are separated at each FB, where the new joint user’s signals still retain a phase distortion. This distortion can be removed by the existing non-coherent detection method. The proposed method has proved effective in computer simulations.