Superimposed training-aided channel estimation for massive MIMO uplink: High mobility case

This paper concerns with the uplink transmission of a massive MIMO system under high mobility environments. By modeling the fading channel as complex exponential basis expansion model, this paper presents a superimposed training (ST)-aided channel estimation scheme, and mathematically characterizes the impact that ST has on the performance of such a very large MIMO system when the number of antennas M grows to infinity. Compared with the existing methods, the proposed scheme requires no additional time-slot reserved for pilots, and thus provide the potential for improving the transmission efficiency. Both theoretical and numerical results validate the effectiveness of our scheme.