Impact of Error weight distribution in MB-OFDM based UWB system with spreading

Abstract

In this paper we evaluate various spreading transforms and their ability to exploit diversity in multi band OFDM based ultra wide band system. The ability of a spreading code to exploit diversity is measured in terms of error weight distribution. Specifically, we consider Hadamard, rotated Hadamard, CI codes and orthogonal Viterbi spreading transforms in this work and present their error weight distribution with QPSK and BPSK modulation. Furthermore, we demonstrate the performance gains achievable by these codes in QPSK and BPSK modulated multi band OFDM based UWB system. In summary, we verify the claim that error weight distribution plays an important role in determining the spreading transform to use