Blind channel shortening in MIMO-OFDM systems using single-block differential modulation

Abstract

In OFDM systems, the inter-symbol interference and interblock interference are eliminated by using a Fourier transform and Cyclic Prefix (CP) redundancy of length higher than the channel size. To preserve a high bit rate, channel shortening technique is required to reduce the redundancy. Recently, a new channel shortening technique for differential encoded SISO-OFDM systems was introduced by Ma el al. This technique is very simple and achieves the channel shortening using only one symbol (the first emitted symbol). In this article, we propose a non-trivial extension of this method to MIMO-OFDM systems. More precisely, we exploit the structure of the first emitted symbol when using single block differential encoding to shorten MIMO channel. The simulation results demonstrate the effectiveness of this new shortening method.