Research On Secure Direction Modulation Of Large Scale Antenna Array

While the direction modulation technology makes full use of the physical characteristics of the antenna array and the rich channel resources, it can solve the security problem of wireless communication.The existing direction modulation technology is mainly based on the antenna array,through the phase shifter or high-speed radio frequency switch in the non expected direction of the constellation diagram to generate random changes. In this paper, we mainly study the direction modulation technology in multi antenna environment, the main work and innovation points can be summarized as follows:(1)Research the direction modulation technology based on phased array, phase shift value can be adjusted in all directions of the constellation by setting the phase shifter. This paper improves the traditional directional modulation technique based on phased array, using multi-objective optimization genetic algorithm to overcome the existing array antenna modulation technique in vertical direction is not sensitive to the problems, making eavesdropping in the vertical direction of the legitimate receiver is still not through the sensitive receiver receives the correct information.(2) Antenna subset selection algorithm of existing main random selection algorithm and simulated annealing algorithm, simulated annealing algorithm can solve the problem of high sidelobe random selection algorithm. But there is no consideration of the deformation of the constellation diagram in the non desired direction. In this paper, the genetic algorithm is used to optimize the traditional antenna subset selection algorithm, which can increase the non- expected direction.(3) The direction modulation technology based on artificial noise is proposed. The existing physical layer security technology, the use of artificial noise are used to the deterioration of the Wiretap Channel, in the direction of modulation combined with artificial noise, in ensuring the invariant constellation look forward to the direction of using artificial noise disturbs the non expected direction of constellation. Through each send a symbol antenna to add artificial noise were randomly selected, the eavesdropper reduced constellation produce random change.