System Design And Performances Analysis For Jamming Modulation Enabled Anti-Jamming Communications

Broadband and strong jamming countermeasures have always been a great challenge in anti-jamming communications.Conventional anti-jamming techniques,such as frequency hopping,direct sequence spread spectrum,interference cancellation,and spatial filtering,mainly adopt the method of avoiding or suppressing jamming attacks.However,these existing anti-jamming techniques are basically ineffective when facing complex electromagnetic cases,especially the broadband and strong jamming ones.To address the above problem,this dissertation proposes a jamming modulation enabled anti-jamming communications(JMEAC)scheme.Unlike conventional mainstream schemes,the key idea of the JMEAC is to utilize jamming signals as the message carrier.In particular,when the jamming signal is detected,signal modulation is achieved by actively scattering the jamming signal;when the jamming signal is absent,the system utilizes a constant signal source for signal modulation.This dissertation optimizes the JMEAC waveform based on the energy efficiency maximization criterion,studies a low-complexity energy detection method without prior information of the jamming signal,theoretically analyzes the system Bit Error Rates(BER)under two typical jamming signals,and deduces the channel capacity and system energy efficiency under Gaussian random jamming signal.Finally,a comparative analysis is conducted on the anti-jamming capabilities of JMEAC,frequency hopping,and direct sequence spread spectrum systems.The study shows that for broadband and strong jamming signals with the constant envelope,JMEAC significantly outperforms frequency hopping and direct sequence spread spectrum communications.The main contributions of this dissertation are summarized as follows:1.A novel anti-jamming system architecture based on the JMEAC scheme is proposed.Based on jamming detection,the JMEAC system unifies transmitter models whether the jamming signal is absent or not.Specifically,jamming modulation is achieved through active backscattering,while using constant radio frequency signals for message transmission when jamming attacks are not detected.For a low receiving complexity,the energy detection method is studied that does not require any prior jamming information.2.The BER performance of JMEAC system is studied.Considering single-tone and white Gaussian noise jamming as representatives of constant envelope and non-constant envelope jamming signals,respectively,this dissertation derives average BER expressions under non-coherent detection.The asymptotic properties of the system BER under the high jamming-to-noise ratio(JNR)are revealed.It is proved that there exists a“BER floor” for sufficient high JNR.3.The channel capacity bound of the JMEAC channel is theoretically studied.Based on the JMEAC channel model,the mutual information maximization problem is formulated.Then,the expressions of the channel capacity and its optimal input distribution are both derived.The numerical solution of the optimal input distribution under the binary input is derived by the interior point method.In addition,the outage probability of the JMEAC system under the fading channel is studied and the ergodic capacity is also derived.4.The energy efficiency of the JMEAC system is studied.Considering the constraints of transmission rate and hardware,the energy efficiency maximization problem of the JMEAC system is formulated and solved by the fractional programming algorithm.Both the optimal waveform design and the corresponding maximum system energy efficiency are derived.In addition,the relationship between the system energy efficiency and transmission rate in the JMEAC system is studied.It is proved that the system energy efficiency is a strictly quasi-convex function over the transmission rate.Under certain conditions,the system energy efficiency increases monotonically with the transmission rate.Furthermore,the asymptotic properties of the system energy efficiency are revealed,and the tradeoff between the system energy efficiency and transmission rate is proved.5.The anti-jamming capacities among JMEAC,traditional frequency hopping,and direct sequence spread spectrum communications are compared,and the system BER performances under different jamming types and scenarios are revealed.The study shows that for constant envelope jamming signals,JMEAC has a good communication performance and outperforms frequency hopping and direct sequence spread spectrum communications under the same broadband and strong(low signal to interference plus noise ratio)jamming cases.In summary,starting from the demand of reliable communication in modern electronic warfare,this dissertation analyzes the status quo of anti-jamming communications and proposes a JMEAC scheme using jamming signals for information transmission to counter broadband and strong jamming attacks.Both the communication mechanism and transmission limits of this scheme are deeply studied.Based on this,a hybrid transmission architecture is designed for different jamming cases.The results of this study provide a theoretical foundation for the engineering application of the JMEAC scheme.It can be applied to the future 6G networks,military Io T,satellite communication,electronic warfare,etc.