THE EFFECT OF PHASE NOISE ON NONCOHERENT DIGITAL-COMMUNICATIONS

Oscillator phase noise is becoming extremely important in broad-band data communications at increasingly higher carrier frequencies. While the effect of phase noise on coherent communications is well documented, the relation between phase noise and decoding in noncoherent systems is more subtle. in this paper, the effect of carrier phase noise on noncoherent decoding is examined. The study concentrates on binary FSK and DPSK, but the results can be easily extended. Expressions are derived that relate decoding error probability to the phase noise spectrums. It is shown that decoding degradation can be accurately approximated by relatively simple integrals involving the phase noise structure function (the latter obtained directly from the phase spectrum). Some examples with reported crystal and Cesium oscillator noise are presented. The key phase noise parameters are the spectral bandwidth relative to the bit rate, and the gain level of the phase noise (the latter dependent on the carrier frequency to which the oscillator is multiplied). Separate results are derived for FSK and DPSK, but the order of the degradation was comparable in both cases. © 1990 IEEE