Physical-layer security based on joint scrambling with spatial and frequency resource

The projection of the random multi-antenna weighted vector structured with spatial scrambling is of constant modulus on the main channel, Eavesdropper can take the advantage of multi-antenna to intercept private information. To solve this problem, we design a kind of physical-layer secrecy method based on the joint scrambling with spatial and frequency resource. Based on the parallel transmission nature of OFDM, we construct a random multiple antenna weighted vector in the each subcarrier, the projection of which on the main channel is equal to a dynamic reference variable. The legitimate user can correctly demodulate the receive signal by this reference variable obtained from the estimation of the reference subcarrier. Meanwhile, because of the difference between the main channel and eavesdropper channel, eavesdropper can´t obtain the useful information. The simulation results show that, when the legitimate users can correctly demodulate the received signal, the eavesdropper can´t intercept the private information using whether blind equalization or MUSIC-like method.