Anti-follower jamming wide gap multi-pattern frequency hopping communication method

This paper deals with the follower jamming(FJ)resistance for the frequency hopping(FH)communication system over additive white Gaussian noise(AWGN)channel.Conventional FH systems are susceptible to be jammed by FJ,and multi-pattern frequency hopping(MPFH)has good resistance to FJ.To further improve the FJ rejection capability of MPFH,we propose a wide gap multi-pattern frequency hopping(WGMPFH)scheme.WGMPFH uses channels to represent messages,and the data channel and complementary channel are hopping on orthogonal frequency slots according to wide gap FH patterns.The transmitted signal lures FJ to aim at the data channel and the complementary channel is away from FJ by adopting wide gap frequency patterns.FJ does not affect the complementary channel but increases the signal energy in the data channel,thus the effect of FJ is reduced.Its bit error rate(BER)is derived under FJ and the effects of three FJ parameters(tracking success probability,jamming duration ratio and jamming bandwidth ratio)on the BER performance of WGMPFH are investigated versus the co nventional FH/BFSK and MPFH system.Numerical and simulation results show that when under the worst-case FJ,the proposed WGMPFH outperforms the MPFH by about 1-3 dB and outperforms the conventional FH/BFSK by more than 4 dB.The proposed WGMPFH shows superior jamming rejection performance under FJ especially in severe signal-to-jamming ratio(SJR).

A sign-function receiving scheme for sine signals enhanced by stochastic resonance

To address the problem that it is difficult to detect an intermediate frequency(IF)signal at the receiving end of a communication system under extremely low signal-to-noise ratio(SNR)conditions,we propose a stochastic resonance(SR)-enhanced sine-signal detection method based on the sign function.By analyzing the SR mechanism of the sine signal and combining it with the characteristics of a dual-sequence frequency-hopping(DSFH)receiver,a periodic stationary solution of the Fokker-Planck equation(FPE)with a time parameter is obtained.The extreme point of the sine signal is selected as the decision time,and the force law of the electromagnetic particles is analyzed.A receiving structure based on the sign function is proposed to maximize the output difference of the system,and the value condition of the sign function is determined.In order to further improve the detection performance,in combination with the central-limit theorem,the sampling points are averaged N times,and the signal-detection problem is transformed into a hypothesis-testing problem under a Gaussian distribution.The theoretical analysis and simulation experiment results confirm that when N is 100 and the SNR is greater than 20 dB,the bit-error ratio(BER)is less than 1.5×10^(-2) under conditions in which the signal conforms to the optimal SR parameters.