Improving Physical-Layer Security for CRNs Using SINR-Based Cooperative Beamforming

• Published in: IEEE transactions on vehicular technology Vol. 65; no. 3; pp. 1835 - 1841
• Main Authors: Zhu, Fengchao, Yao, Minli
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.03.2016; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Array signal processing; Cognitive radio network (CRN); cooperative beamforming; Interference; Null space; Physical layer; physical layer security; Power demand; Security; semi-definite programming (SDP); semi-definite relaxation (SDR); Signal to noise ratio; cooperative beamforming; semi-definite relaxation (SDR); physical-layer security; Cognitive radio network (CRN); semi-definite programming (SDP)
• ISSN: 0018-9545; 1939-9359
• DOI: 10.1109/TVT.2015.2412152

In this paper, we consider a new cognitive radio network (CRN), where cooperative beamforming is designed to enhance the physical-layer security for both primary users (PUs) and secondary users (SUs). In particular, the proposed design aims to minimize the transmit power of a secondary transmitter (ST) while providing an eavesdropper (Eve), a primary receiver (PR), and multiple secondary receivers (SRs) with different signal-to-interference-plus-noise ratio (SINR). The semi-definite relaxation (SDR) technique is utilized to convert the initial nonconvex problem into a convex semi-definite programming (SDP), which can be efficiently solved. Then, the optimality of SDR is strictly proved by showing that optimal transmit covariances must be rank one. Numerical examples are provided to corroborate the proposed studies.