Enhanced performance for MIMO channel estimation based on implicit ZCZ training sequences

This paper addresses the problem of multiple-input multiple-output (MIMO) frequency selective channel estimation using implicit training without dc-offset (direct current). In order to remove the dc-offset directly without introducing extra complexity, the ZCZ (Zero correlation zone) set with balance properties can be used as training sequences. Since the transmitted data from each antenna is first pre-processed and then arithmetically added onto the training sequences, thus the influence of the unknown data to the channel estimation existed in normal implicit method can be cancelled. In this paper, error variance of channel estimation vector is derived, and time-domain analysis is performed. Our theoretical analysis and simulation results validate the superiority of the new method compared with the conventional implicit estimation method.