Physical layer assisted security for mobile OFDM networks

Secure wireless communication is a challenging problem due to the shared nature of the wireless medium and the dynamic channel. Most of the existing security mechanisms focus on traditional cryptographic schemes. In recent years, features of multi-path channels, such as randomness, coherence and reciprocity, have driven researchers to exploit their potential to enhance the security of mobile wireless networks. As OFDM occupies wide bandwidth, it will experience a prolific source of multi-path components. In this paper, we comprehensively exploit the inherent physical features of the multi-path fading channel to achieve continuous two way authentication between mobile terminals. In our scheme, the coherence of the time-variant channel for the continuous symbols is exploited to achieve authentication of the OFDM communication networks. Unlike other channel-based approaches, the coherence of both amplitude and phase of the channel signature in the continuous symbol is utilized to enhance the security of the OFDM communication network. More specifically, the receiver will detect the channel response continuously according to the inserted pilots and identify the legal user based on the statistical channel signature information. Simulation results indicate the high efficiency of our proposed method.