Jin Yifeng, Li Xunan, Lv Guocheng, Zhao Meihui, Jin Ye
School of Electronics, Peking University, Beijing 100871, China.
National Computer Network Emergency Response Technical Team Coordination Center of China, Beijing 100029, China.
Sensors (Basel). 2022 Mar 21;22(6):2398. doi: 10.3390/s22062398.
The security issue of wireless communication is a common concern because of its broadcast nature, especially when the relay becomes an eavesdropper. In the orthogonal frequency division multiplexing (OFDM) relay system, when the relay is untrusted, the security of the system faces serious threats. Although there exist some resource allocation schemes in a single-carrier system with untrusted relaying, it is difficult to apply them to the multi-carrier system. Hence, a resource allocation scheme for the multi-carrier system is needed. Compared to the one-way relay system, a two-way relay system can improve the data transmission efficiency. In this paper, we consider joint secure resource allocation for a two-way cooperative OFDM system with an untrusted relay. The joint resource allocation problem of power allocation and subcarrier pairing is formulated to maximize the sum secrecy rate of the system under individual power constraints. To solve the non-convex problem efficiently, we propose an algorithm based on the alternative optimization method. The proposed algorithm is evaluated by simulation results and compared with the benchmarks in the literature. According to the numerical results, in a high signal-to-noise ratio (SNR) scenario, the proposed algorithm improves the achievable sum secrecy rate of the system by more than 15% over conventional algorithms.
由于无线通信的广播特性，其安全问题备受关注，尤其是当中继成为窃听者时。在正交频分复用（OFDM）中继系统中，当中继不可信时，系统安全面临严重威胁。虽然在具有不可信中继的单载波系统中存在一些资源分配方案，但将它们应用于多载波系统却很困难。因此，需要一种适用于多载波系统的资源分配方案。与单向中继系统相比，双向中继系统可以提高数据传输效率。本文考虑了具有不可信中继的双向协作OFDM系统的联合安全资源分配问题。提出了功率分配和子载波配对的联合资源分配问题，以在个体功率约束下最大化系统的总保密率。为了有效解决该非凸问题，我们提出了一种基于交替优化方法的算法。通过仿真结果对所提算法进行了评估，并与文献中的基准算法进行了比较。根据数值结果，在高信噪比（SNR）场景下，所提算法比传统算法将系统可实现的总保密率提高了15%以上。
