中文摘要：

考虑一个存在多窃听者的多小区下行链路蜂窝网络,协作小区通过在选定的子载波上执行协作波束赋形,利用小区间干扰抑制窃听者,实现安全传输。在窃听者位置未知的情况下,推导了下行链路保密连接概率的闭式表达式。在此基础上,将下行链路建模为博弈参与者,该文提出一种基于联盟博弈的多小区下行链路保密协作算法,以保密连接概率为效用函数,通过设计联盟加入和退出规则,实现了下行链路对子载波的高效选择和保密协作联盟的自组织生成。理论和仿真分析表明所提算法能够形成稳定的联盟结构,并且所提算法的保密性能优于传统的联盟协作算法。

英文摘要：

This paper studies physical layer security of the multi-cell cellular networks, where the base stations need to perform cooperation beamforming in selected subcarriers to secure the downlink communication, and eavesdroppers with random location are interfered by inter-cell interference. Firstly, the approximation for the secrecy connection probability with uncertained locations of eavesdroppers is obtained. Then a distributed coalition game based cooperation algorithm is proposed to maximize the secrecy connection probability of downlinks. Specifically, the downlink is modeled as game player, whose payoff is the secrecy connection probability in the selected coalition, the join and quit rules of coalitions are designed to make downlinks self-organizing form cooperative coalition and achieve the effective subcarrier allocation. Moreover, the convergence of the proposed coalition formation game is proved, theoretical analysis and simulation results show that the proposed algorithm can form a stable coalitional structure and results in a notable secure performance advantage relative to the traditional cooperation algorithms.