Multipath distortion of differentially encoded GMSK with 2-b differential detection in bandlimited frequency-selective mobile radio channel

Error performance of Gaussian minimum-shift keying (GMSK) with 2-b differential detection in a frequency-selective mobile radio channel is analyzed. The two-wave model using two Rayleigh waves with constant group time-delay is adopted to describe a frequency-selective mobile radio channel. The Gaussian-type bandpass filter is introduced as a receiving filter to demonstrate the effects of band limitation at the receiver. A preferable receiving bandwidth in the frequency-selective mobile channel is also discussed. It is shown that the preferable receiving bandwidth is almost that obtained in an additive Gaussian noise channel since the magnitude of the interfering (or delayed) wave is relatively small. It is hardly affected by the maximum Doppler frequency and remains almost constant for the various parameters, e.g. average carrier-to-noise power ratio.<
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