Blind channel estimation in MIMO-OFDM systems using semi-definite relaxation

A new blind channel estimation technique for multiple-input multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM) systems is proposed. It estimates the channel parameters in the time domain jointly for all subcarriers instead of doing this in the frequency domain independently for each subcarrier. This results in a substantially improved parsimony of the channel parameterization along with the ability to use coherent processing across the subcarriers. It is shown that using semi-definite relaxation (SDR), our channel estimation problem can be transferred to a convex form and then solved efficiently using modern convex optimization tools.