UC Riverside

Physical layer security (PLS) is an approach that provides secrecy based on information-theoretic model which does not account for any computation capability assumption or pre-installed standardized secret key generation algorithm and it is a good additional protection on the top of the existing security scheme. This work includes four different topics which are about improving PLS with full-duplex radio. In the first topic, we develop a fast algorithms for computing power allocations in subcarriers, subject to power and rate constraints, to maximize the secrecy capacity of a three-node network consisting of a source, a full-duplex capable destination and an eavesdropper. The optimal power allocation at the destination is found to be significant especially when its power budget is high. The second topic is about the analysis of a two-phase scheme for secret information transmission with the technique of anti-eavesdropping channel estimation (ANECE), which requires full duplex transceiver and it can better handle Eve with any number of antennas. The analysis is based on the assumption that everyone has a prior statistical knowledge of the channel state information (CSI) anywhere and it yields lower and upper bounds on secure degrees of freedom as functions of the number of antennas on Eve and the size of information packet. For the third topic, we present optimal designs of the pilots for ANECE based on two criteria. The first is to optimize the minimum mean squared error (MMSE) channel estimation for the users, and the second is to maximize the mutual information between the pilot-driven signals observed by the users. Closed-form optimal pilots are shown under both criteria but subject to a symmetric and isotropic condition. Algorithms for computing the optimal pilots are shown for general cases. In the fourth topic, we analyze the secure degree of freedom and the asymptotic expression of the achievable secret key rate from a two-phase key generation scheme which consists of channel training phase and secure information transmission phase. Based on the asymptotic form, we develop an effective algorithm for coherence time allocation between the two phases to maximize the achievable secret key rate.