| Summary: | A new matched filter bound (MFB) for a dispersive Rician fading channel with
unrestricted normalized Doppler rate is presented. Analytical expressions are derived for BPSK
modulation.
The channel model is based on the standard linear time varying filter. The BER performance,
in general, is found to improve with an increase in the fading rate due to the inherent
diversity present within a single pulse. The shape of the transmitted pulse is shown to affect the
BER in fast fading conditions. It has been found that the specular component improves the BER at
lower fading rates; for very high fading rates, the implicit diversity effect becomes dominant in
diminishing the effect of fading.
Discrete (two and three beam) models are assumed for the dispersive channel. The error
bounds for the three-beam model are derived as a function of the inter-beam delay and correlation
parameters. In general, the delay spread was found to result in lowering the BER for both the slow
and fast fading cases when the fading in the beams is uncorrelated. In the two-beam frequency
selective case, the BER is very sensitive to the degree of beam overlap.
Finally, assuming errors in estimating the channel fading waveform, the BER for a non-ideal
receive filter is obtained. It was observed that, for the specified model, the system degradation
is higher for phase mismatches than for amplitude mismatches for a given error variance.
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