Performance of wideband signaling for slowly fading frequency selective channels

The optimum performance of a wideband system operating over slowly fading frequency selective channels is evaluated. Although it is well known that system performance is directly related to the product of RMS delay spread of the channel and operating bandwidth of the system, as well as to signal-to-noise ratio, the exact relationship is not known and approximations are generally applied. A procedure for deriving the average probability of error as the performance measure is given. The analysis is formulated using a frequency domain approach that applies equally well to direct spread or frequency hopped spread spectrum systems or to systems that use adaptive decision feedback equalization or adaptive maximum-likelihood sequence estimation. The analysis is used to study a simple uncoded system, and to verify a channel model that is used for simulation. The method is illustrated for a troposcatter channel described by a delay power spectrum, or equivalently, a frequency correlation function