A Frame Design for MIMO UW based Systems: Overhead Analysis & Channel Estimation

In this paper, we extend the conventional single-input-single-output unique word (UW) based frame designs to MIMO applications with spatial multiplexing. Considering a doubly-dispersive channel where the channel is varying both in time and frequency, we analyze the overhead requirements of such systems for synchronization and channel estimation. Through numerical and simulation results, we show that the proposed MIMO UW based frame design, achieves a higher transmission efficiency than the traditional cyclic prefix approach as in orthogonal frequency division multiplexing (CP-OFDM). Derivations of the linear minimum mean squared error channel estimation of MIMO UW sequences show that the channel estimation performance can be highly improved with respect to CP-OFDM systems in doubly-dispersive channels.