Ultra-wideband signals in a Rician fading channel

This paper presents an analysis of the link performance of ultra-wideband (UWB) signals using a new figure of merit which is based on ability of UWB signals to mitigate the effect of channel fading. The new figure of merit is defined as the coefficient of variation (CV) of the received wideband signal power, which is a measure of the variation in the received signal power around its mean. A general expression for the CV of the received signal power for UWB signals in Rician fading multipath channels is derived. The CV expression is a function of multiple parameters: transmitted signal pulse energy spectral density, the chip duration, the channel delay spread and the specular-to-diffuse power ratio (also known as the Rician K-factor). It is shown that CV decreases with bandwidth spreading. An expression for the bit error rate is derived that depends on the CV of the received signal power. The CV can then be used as a measure for comparing the effect of pulse shapes on the system performance.