The Random Beamforming Security Scheme of Physical Layer

In conventional information theory research on physical layer security, to lower the requirement of the main channel quality, the random beamforming security scheme (RBS) is presented in this paper. This method sends the information data on the direction of the main channel, and adds multiplicative interference on the vertical direction. As a result, this scheme converts the channel characteristic (such as channel states vector) difference between the main channel and the wiretap channel to the channel quality difference, and makes the secrecy capacity positive. For the completeness of RBS, we solved three problems: 1) Presenting the construction method of RBS in vector space; 2) Calculating the secrecy capacity and optimum source distribution; 3) Constructing the artificial noise. Finally, with the RBS in transmitting diversity system, after designing and simulating the noise generating, power allocation scheme, we illustrate that RBS can get a positive secrecy capacity, even the main channel is worse than the wiretap channel.