Modified Whitening Rotation based Joint Semi-blind Channel and Data Estimation Scheme for Rayleigh Flat Fading MIMO channels

In this paper, we propose a novel joint semi-blind channel and data estimation technique based on Whitening Rotation (WR) method for Rayleigh flat fading Multiple Input Multiple output (MIMO) channel using different receiver antennas combinations. Here we divide newly proposed technique in three steps. In the first step, we use conventional Whitening Rotation based semi-blind channel estimation technique, where MIMO channel matrix H can be decomposed as H=WQ H . Whitening matrix W can be estimated blindly using second order statistical information of received data and unitary rotation matrix Q can be estimated exclusively using Orthogonal Pilot Maximum Likelihood (OPML) algorithm. In the second step, data symbols can be estimated using estimated channel H and received output data by applying maximum likelihood data estimation method. Finally in the third step, Q can be re-estimated as a Q new using OPML algorithm by considering estimated blind data symbols itself as a pilot symbols for more statistical information of unitary matrix and perform final channel estimation H final=W Q new H . Simulation results are presented under 4-PSK data modulation scheme for two transmitters and different combinations of receiver antennas to support proposed novel technique and they demonstrate improved BER performance compared to conventional WR based optimal technique and Rotation Optimization Maximum Likelihood (ROML) based suboptimal semi-blind channel estimation technique. KeywordsMultiple Input Multiple Output, Orthogonal Pilot Maximum Likelihood technique, Whitening Rotation based Semi Blind Channel Estimation , Rotation Optimization Maximum Likelihood technique