Performance of Direct Sequence Ultra Wide Band Signals over Log-normal Fading Channels

In this paper, the probabilities of error performances of bipolar Direct Sequence Ultra Wide Band (DS-UWB) signals are investigated over a log-normal fading channel. Since the bandwidth of UWB signals is in the level of giga Hertz, the number of the resolvable paths in the channel is large. Consequently, in the receiver, a Rake receiver in conjunction with a maximum ratio combiner is used. By using the derived probability of error expression, the numerical values of the performances are calculated for the first derivative of Gaussian, the second derivative of Gaussian, Rayleigh and Daubechies-5 (db-5) pulse signals. Results show that the db-5 pulse based UWB system gives the best performance.