Equivalent Tapped Delay Line Channel Responses with Reduced Taps

Typically, a multipath channel response can be characterized as a sum of Rayleigh-fading ´´rays´´, each defined by a time delay and a mean-square amplitude. Therefore, the channel response can be largely described by a power delay profile (PDP), which is the set of mean-square ray amplitudes and relative delays. Here, we address the following question: Given an actual (or ´´true´´) PDP, PDP(τ), which may have many rays, is there a 3-ray (i.e. 3- tap) equivalent response, derivable from PDP(τ), that can be used to accurately estimate the average bit error rate, <;BER>, vs. receiver input signal- to-noise ratio, SNR? The results reported here give an affirmative answer, e.g., for <;BER> values down to = 10^-4, the required SNR using a 3-tap equivalent channel response is less than 1.1 dB larger than that required for the ´´true´´ channel. This agreement can be improved upon, suggesting further work on deriving and evaluating equivalent 3-tap channels. We discuss the benefits of such simplifications for hardware emulators as well as for simulation and analysis.