Low complexity channel shortening technique applied to MB-OFDM UWB systems

In this paper, we investigate the use of a channel shortening filter (CSF) for multiband orthogonal frequency division multiplexing ultra wideband (MB-OFDM UWB) communication systems. Indoor wideband channels are known as rich scattering environments resulting in potentially large delay spread. When the delay spread exceeds the guard interval length, intersymbol interference (ISI) and intercarrier interference (ICI) may occur. The aim of this paper is to reduce the time dispersion of the indoor wideband channels while not increasing the system complexity compared to the conventional channel shortening techniques. We propose to divide the CSF into an energy concentration and a tail suppression parts. We then introduce an algorithm to efficiently compute the coefficients of each CSF part. We show that the proposed method can considerably improve the system performance at high data rate as well as the computational complexity compared to classical channel shortening designs.