0/1 space hopping technique using backward training method with pre-compensation

0/1 space hopping technique is a multi-antenna secure wireless transmission scheme which exploits the space spectrum at both the transmitter side and the receiver side. However, 0/1 space hopping using the forward training method (FTM) may lead to interception when the training method and the space hopping pattern are both known to an eavesdropper. The backward training method with weight-feedback (BTM-WF), which can solve the above security problem, however, suffers from low efficiency and the feedback process. In this paper, backward training method with pre-compensation (BTM-PC) is proposed. The new method achieves higher efficiency by transmitting only one training symbol with all the antennas of the target receiver. Channel knowledge is acquired at the transmitter through training and used in pre-compensation. Thus the receiver can correctly receive information without any feedback, and then, through further adjustment, achieve the same performance as FTM and BTM-WF, while the eavesdropper always cannot intercept the information. The security of BTM-PC, as well as the influence of noise on the proposed method and the corresponding countermeasure, is also discussed in detail. Simulation results are presented to show the validity of the BTM-PC.