[01] Andriy Bondariev, Department of Theoretical Radiotechnics and Radiomeasuring, Lviv Polytechnic National University, Lviv, Ukraine. [02] Ivan Maksymiv, Department of Theoretical Radiotechnics and Radiomeasuring, Lviv Polytechnic National University, Lviv, Ukraine.

In this paper the method of improvement noise immunity of signals with quadrature phase shift keying is given. In particular, offset quadrature phase-shift keying (OQPSK) signals are considered. The method lies in modification of existing demodulators with application of additional specific narrowband filters in signal phase detector. The simulation model of modified phase detector was realized and the results of its research are given. The results of simulation show that application of modified detector significantly improves noise immunity of OQPSK signals revealing new opportunities of modernization of existing cellular networks.

OQPSK, PLL, BER, SNR, Shannon's Limit, Cellular Network, Noise Immunity, Phase Detector

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