Research On Friendly Jamming Method Against MIMO Eavesdropping

With the development of 5G technology and the Io T Tech,various types of wireless devices are growing rapidly and continuously,and how to protect the communication security between heterogeneous devices has become a severe challenge.Friendly jamming is a physical layer security technology that does not rely on secret keys.It uses artificial noise to interfere with eavesdroppers to achieve confidential communication.It can provide a flexible communication security solution for wireless communications that have been widely deployed without key or weak key protection,and wireless communications between resource-constrained devices.However,in today's wireless communication systems,MIMO eavesdroppers can remove artificial noise by separating the received signal,thereby obtaining confidential information,which is a difficult point in friendly jamming technology.Aiming at the problem of MIMO eavesdropping,our thesis carried out the following research work:(1)A friendly jamming model under MIMO eavesdropping channel is established.Based on information theory,the main channel capacity,eavesdropping channel capacity and security capacity are deduced respectively.The calculation and analysis of the security capacity show that under the appropriate jamming signal strength,the security capacity is generally greater than zero in typical application scenarios.(2)On the basis of summarizing the existing problems of the existing scheme,a new transmission signal modulation and demodulation scheme of friendly jamming called "differential energy modulation" is proposed.This solution differentially encodes binary digital signals and uses Gaussian noise as the carrier signal instead of traditional amplitude-phase modulation.It aims to eliminate the non-Gaussian characteristics of the training sequence in the data frame and the modulated signal,and increase the uncertainty in the separation of mixed signals for MIMO eavesdroppers.(3)The safety and effectiveness of the proposed scheme are evaluated by simulation and experiment,and compared with traditional amplitude-phase modulation.For a given simulation scenario,the friendly jamming using differential energy modulation can increase the average bit error rate of MIMO eavesdroppers by 34%;for the experimental scenario,the average bit error rate is increased by 38%.