Performance of Selection Diversity MFSK in the Presence of Estimation Errors

The performance of the selection diversity combiner is studied. Unlike most previous works where perfect knowledge of the signal amplitude and the noise power is assumed, in this analysis, knowledge of the signal amplitude and the noise power is obtained by using practical estimators that introduce estimation errors. The average symbol error rate of the combiner is derived for non-coherent M-ary frequency shift keying signals, independent and non-identically distributed diversity branches and unequal noise powers. The effect of estimation errors on the performance of the combiner is evaluated and illustrated by numerical examples. An interesting and useful conclusion is that it is disadvantageous to employ signal-to-noise ratio as a branch selection criterion when the branch noise powers are known a priori to be equal.