Joint power allocation and relay selection for decode-and-forward cooperative relay in secure communication  

作　　者：YANG Yun-chuan ZHAO Hui SUN Cong WANG Wen-bo 

机构地区：[1]Key Laboratory of Universal Wireless Communications, Beijing University of Posts and Telecommunications [2]ICMSEC, AMSS, Chinese Academy of Sciences

出　　处：《The Journal of China Universities of Posts and Telecommunications》2013年第2期79-85,共7页中国邮电高校学报（英文版）

基　　金：supported by the National Key Technology R&D Program of China(2012ZX03004005);the Foundational Research Funds for the Central Universities

摘　　要：In this paper, we investigate the cooperative strategy with total power constraint in decode-and-forward （DF） relaying scenario, in the presence of an eavesdropper. Due to the difference of channel for each source-relay link, not all relay nodes have constructive impacts on the achievable secrecy rate. Besides, the final achieved secrecy rate depends on both source-relay and relay-destination links in DF relaying scenario. Therefore, the principal question here is how to select cooperative strategy among relays with proper power allocation to maximize the secrecy rate. Three strategies are considered in this paper. First, we investigate the cooperative jamming （CJ） strategy, where one relay with achieved target transmission rate is selected as a conventional relay forwarding signal, and remaining relays generate artificial noise via CJ strategy to disrupt the eavesdropper. Two CJ schemes with closed-form solutions, optimal cooperative jamming （OCJ） and null space cooperative jamming （NSCJ）, are proposed. With these solutions, the corresponding power allocation is formulated as a geometric programming （GP） problem and solved efficiently by convex programming technique. Then, to exploit the cooperative diversity, we investigate the cooperative relaying （CR） strategy. An iterative algorithm using semi-definite programming （SDP） and GP together with bisection search method is proposed to optimize the cooperative relaying weight and power allocated to the source and relays. Furthermore, to exploit the advantages of both CR and CJ, we propose an adaptive strategy to enhance the security. Simulation results demonstrate that the efficiency of the proposed cooperative strategies in terms of secrecy rate.In this paper, we investigate the cooperative strategy with total power constraint in decode-and-forward （DF） relaying scenario, in the presence of an eavesdropper. Due to the difference of channel for each source-relay link, not all relay nodes have constructive impacts on the achievable secrecy rate. Besides, the final achieved secrecy rate depends on both source-relay and relay-destination links in DF relaying scenario. Therefore, the principal question here is how to select cooperative strategy among relays with proper power allocation to maximize the secrecy rate. Three strategies are considered in this paper. First, we investigate the cooperative jamming （CJ） strategy, where one relay with achieved target transmission rate is selected as a conventional relay forwarding signal, and remaining relays generate artificial noise via CJ strategy to disrupt the eavesdropper. Two CJ schemes with closed-form solutions, optimal cooperative jamming （OCJ） and null space cooperative jamming （NSCJ）, are proposed. With these solutions, the corresponding power allocation is formulated as a geometric programming （GP） problem and solved efficiently by convex programming technique. Then, to exploit the cooperative diversity, we investigate the cooperative relaying （CR） strategy. An iterative algorithm using semi-definite programming （SDP） and GP together with bisection search method is proposed to optimize the cooperative relaying weight and power allocated to the source and relays. Furthermore, to exploit the advantages of both CR and CJ, we propose an adaptive strategy to enhance the security. Simulation results demonstrate that the efficiency of the proposed cooperative strategies in terms of secrecy rate.

关 键 词：physical layer security CJ CR power allocation SDP GP 

分 类 号：TN925[电子电信—通信与信息系统]