Circular orthogonal sequences based channel estimation for MIMO SC-FDE systems

Channel estimation in low SNRs is challenging for multiple-input multiple-output single carrier frequency domain equalization (MIMO SC-FDE) systems. This paper presents a novel design of training sequences with circular orthogonal properties, which can be applied to accurate channel estimation. The orthogonality of training sequences help to eliminate the interference between the transmit antennas, while circular orthogonality guarantees the identification of every resolvable delay bin of each multipath channel at the receiver. Compared to the traditional frequency-domain channel estimation methods, the proposed algorithm not only suppresses the interference between the antennas but also decreases the variance of the noise, resulting in the improvement in MSE of channel estimation and BER performance of the system. Simulation results demonstrate the effectiveness and feasibility of the proposed algorithm.