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

The projection of multi-antenna weighted vector structured with spatial scrambling is of constant modulus on the legitimate channel. Eavesdropper can take the advantage of multi-antenna to intercept private information. To solve this issue, a kind of physical-layer security algorithm is designed based on the joint scrambling with spatial and frequency resource. Firstly, random multi-antenna weighted vector is constructed in each subcarrier, and the vectors projection on the legitimate channel is equal to a reference variable that changes randomly in each OFDM symbol. Secondly, the weighted vector delivering the reference variable is transmitted in the reference subcarrier, with which the legitimate user can correctly demodulate the remaining subcarriers. Whereas, eavesdropper can not obtain the useful information because of the nature difference between the legitimate channel and eavesdropper channel. The simulation results show that, when SNR achieves 10 dB, the legitimate user's Bit Eerror Rate (BER) is 10-5, the eavesdropper can not intercept the private information using blind equalization or MUSIC-like method.