基于用户分簇的物理层增强安全多播算法

物理层安全技术是无线网络技术中一项重要的关键技术。在大量多播用户和窃听用户共存的场景中，针对传统物理层安全技术中在波束赋形下增加人工噪声时不能很好地应用于多播传输的问题，提出了一种基于多播用户分簇策略下的物理层增强安全多播算法。首先，具有相近信道矢量的多播用户被分为同一个多播簇，不同的多播簇分配不同的子载波传输多播数据；其次，基于多播用户分簇策略的结果，提出了通过采用联合功率分配和波束赋形设计算法，最大化整个多播系统的安全多播速率；最后，为了降低算法的计算复杂度，提出了新的搜索算法处理联合功率分配和波束赋形设计算法。仿真结果显示：与传统安全多播算法相比，基于多播用户分簇策略的物理层增强安全多播算法不但能够获得更高的多播安全传输速率，而且其计算复杂度也大大低于采用遍历搜索的传统安全多播算法。

Physical Layer Enhanced Secure Multicast Algorithm Based on User Clustering

Physical-layer security has become a critical technique in current wireless networks.The existing conventional physical layer security techniques,e.g. artificial-noise-aided transmit beamforming,do not apply well to multicast transmission from large multicast user and eavesdropper user numbers.To address this problem,an enhanced secure multicast algorithm based on user clustering scheme was proposed.Firstly,the multicast users with close channel vectors were divided into a cluster and different clusters were served on different channels.Secondly,a heuristic joint power allocation and beamforming design algorithm based on this user clustering scheme were proposed to maximize the globally achievable secure multicast rate.Finally,to reduce the overall computation complexity,the new searching method was put forward to solve power allocation and beamforming design jointly.Simulation results showed that the enhanced secure multicast algorithm can support a much higher secure transmission rate than conventional secure multicast (CSM) schemes,and the proposed joint power allocation and beamforming design algorithm outperform existing CSM schemes with the ergodic searching method greatly in terms of computation complexity.