A New MSK Spread Spectrum Incoherent Reception Method in Large Doppler Environment
Aiming at the difficulties of unstable operation and complicated realization of traditional coherent receivers in high dynamic and extremely low signal-to-noise ratio environments,a spread-spectrum incoherent reception method for MSK regime is proposed.Firstly,the phase characteristics of MSK signals are analyzed,the influence of the cumulative phase deviation caused by Doppler frequency deviation on the reception performance is deduced,and a composite mesh phase compensation model is constructed to theoretically derive the adaptive ability of its Doppler frequency deviation range.On this basis,a joint de-spreading and demodulation incoherent reception method based on differential phase correlation is proposed.The results of simulations and experiments show that the performance of this reception method is improved by about 2 dB compared with the conventional DSSS-MSK system under the same spreading factor;when the transmission bandwidth is 20 MHz,the number of composite grids at the receiver is 5,and the minimum phase rotation is 0.06π,the proposed method maintains favorable stability over the theoretically derived Doppler frequency deviation range of 750 kHz.The proposed method has the advantages of excellent performance,strong adaptability to frequency deviation,and low realization complexity,and it has a promising application prospect in the communication scenarios with high dynamics and low signal-to-noise ratio.
MSKIncoherent receptionJoint de-spreading and demodulationSpread spectrum gainDoppler frequency deviation
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