Error Rate Estimation for DS-IR and DS-UWB over Frequency Selective Channels

We consider a single user direct sequence impulse radio (DS-IR) system operating with a QPSK constellation over a deterministic, frequency selective channel and affected by additive white Gaussian noise (AWGN). We present a method to obtain a fast and accurate estimation of the symbol error rate (SER) when the receiver is a correlation receiver with perfect synchronization and channel knowledge. The method is based on the estimation of the Inter Symbol Interference (ISI) distribution by means of the characteristic function (CF) approach. The results also apply to direct sequence ultra wideband (DS-UWB) modulation since it is a special case of DS-IR. The accuracy of the method is verified by comparing the SER prediction with that obtained by means of Monte Carlo (MC) simulation.