EFFECT OF PHASE-SHIFT INTERFERENCE ON THE NOISE IMMUNITY OF CORRELATION DEMODULATOR OF SIGNALS WITH MULTIPLE PHASE SHIFT KEYING

Abstract

The energy and spectral advantages of signals with phase shift keying predetermined their widespread use in modern digital navigation, communications and television systems. The use of such signals is the base of communication standards of DVB-S, DVB-S2 / S2X, GLONASS, CDMA, WiFi IEEE 802.11 and others. To increase the capacity of radio channels, multiple phase shift keying (MPSK) is applied. This increases the number of possible phase states of the signal and, thus, the information capacity of the channel symbol. However, such an increase greatly affects the noise immunity of MPSK signal reception. In the article the noise immunity of receiving signals with multiple phase shift keying in the presence of noise and phase-shift interference is analyzed by the methods of statistical radio engineering. The dependencies of bit error probability on the signal-to-noise ratio, on the interference intensity, on the relative transmission speed of the interference, and on its detuning relative to the center frequency of the spectrum of the useful signal are calculated. It is shown that signals with multiple phase shift keying are very strongly influenced by phase-shift interference, and this influence increases with increasing signal positionality. The degree of reduction of the noise immunity of the reception depends on the magnitude of the relative transmission rate of the interference and its intensity. The damaging effect of the phase-shift interference is most pronounced when it hits the main lobe of the signal spectrum. As the relative transmission rate increases, the interference becomes more broadband and pseudo-noise, and it affects even with very large frequency detuning somewhat decreasing in the region of the main lobe of the signal spectrum. This decrease seems natural, since the analyzed algorithm for receiving MPSK signals is optimal for the effects of noise interference.