Rake Performance after Channel Shortening by Decay Factor Optimization in UWB Channels

In this paper, we present a novel channel shortening algorithm developed in particular for ultra wideband (UWB) communication systems. This algorithm makes use of exponentially decaying characteristics of the UWB channel models. It optimizes the channel decaying factor within a desired temporal window in the effective channel while keeping the channel decaying factor constrained elsewhere. The presence of the proposed channel shortening equalizer before rake reception greatly simplifies the rake receiver architecture by significantly reducing the number of channel taps. We compare its performance with all, selective and partial rakes in terms of captured channel energy, rake combining delay and bit error rate (BER). Simulation results show that the proposed algorithm improves the performance of the Rake receiver in dense multipath UWB channels and considerably reduces its structure complexity.