Abstract
Binary differential phase-shift keying (2DPSK) signal is mainly used for high speed data transmission. However, the bit error rate of digital signal receiver is high in the case of wicked channel environment. In view of this situation, a novel method based on stochastic resonance (SR) is proposed, which is aimed to reduce the bit error rate of 2DPSK signal by coherent demodulation receiving. According to the theory of SR, a nonlinear receiver model is established, which is used to receive 2DPSK signal under small signal-to-noise ratio (SNR) circumstances (between −15 dB and 5 dB), and compared with the conventional demodulation method. The experimental results demonstrate that when the input SNR is in the range of −15 dB to 5 dB, the output bit error rate of nonlinear system model based on SR has a significant decline compared to the conventional model. It could reduce 86.15% when the input SNR equals −7 dB. Meanwhile, the peak value of the output signal spectrum is 4.25 times as that of the conventional model. Consequently, the output signal of the system is more likely to be detected and the accuracy can be greatly improved.
Highlights
Binary differential phase-shift keying (2DPSK) transmits the digital information using carrier wave’s relative phase change of adjacent code element, called binary relative phase-shift keying (PSK). 2DPSK has advantages over amplitude-shift keying (ASK) and frequency-shift keying (FSK) in terms of the anti-noise performanceD
The nonlinear receiver model is established on the basis of the principle of stochastic resonance (SR), the SR phenomenon of 2DPSK signal through nonlinear bistable system is studied
When the input signal-to-noise ratio (SNR) is between −15 dB and 5 dB, the SR system model is superior to the conventional model found in three aspects, namely, the time-domain, the frequency-domain and the system output bit error rate, by the comparison of 2DPSK signal, respectively, through the SR nonlinear system model and the conventional linear coherent demodulation model
Summary
Binary differential phase-shift keying (2DPSK) transmits the digital information using carrier wave’s relative phase change of adjacent code element, called binary relative phase-shift keying (PSK). 2DPSK has advantages over amplitude-shift keying (ASK) and frequency-shift keying (FSK) in terms of the anti-noise performance. The conventional demodulation methods of 2DPSK signal contain coherent demodulation (polarity comparison method) added code inverse transform and differential coherent demodulation (phase comparison method).[2] While these methods require high signal-to-noise ratio (SNR), they are unable to demodulate weak 2DPSK signal. The researches on the applications of SR in digital signal processing are relatively few. This paper presents a new method for the demodulation of weak 2DPSK signals based on the theory of SR. Nonlinear demodulation method based on the theory of SR is analyzed and compared with the conventional demodulation method in the condition of the heavy background noise with the SNR less than 0 dB from three cases that contain the time-domain, the frequency-domain and the bit error rate of the system output. The advantage of SR in the digital signal processing can be found
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