多用户干扰网络中基于干扰对齐的安全传输方案

Interference alignment based secure transmission scheme in multi-user interference networks

面向物联网业务中的信息安全需求,考虑多用户干扰网络中存在多个窃听节点的场景,提出基于干扰对齐(IA,interference alignment)的物理层安全传输方案。为解决传统干扰对齐算法可能导致保密信号消除的问题,提出一种改进的交替最小化(AM,alternating minimization)方法,通过交替优化发射和接收矩阵消除多用户干扰,同时利用人工噪声(AN,artificial noise)辅助的最大特征模式波束成形(max-eigenmode beamforming)进行安全传输。为更加准确地分析该方案的可行性,提出将干扰对齐方程分解为独立的子方程及其组合,通过分析每个方程的可解性,得到了更严格的可行性必要条件。最后,通过优化保密信号和人工噪声之间的功率分配比例,在满足安全中断概率(SOP)的约束下,实现安全传输速率的最大化。仿真结果表明,该方案不但可以保证保密信号的质量,同时可以提高安全性能,因此可以更好地支持多用户干扰网络中的安全业务。

Faced with the requirement of information security in internet of things,a scenario of multi-user interference networks with multiple eavesdroppers was considered,and an interference alignment(IA)scheme based physical layer secure transmission was proposed.Traditional IA security algorithm may result in secret signal cancellation.To overcome this threat,a modified alternating minimization(AM)method was proposed.The multi-user interference was eliminated by alternatively optimizing transceiver matrices,and artificial noise(AN)aided max-eigenmode beamforming was employed for secure transmission.To obtain a more accurate analysis of IA feasibility,the IA equation was divided into independent subsets and their combinations.By analyzing each case,a much tighter necessary condition for IA feasibility was established.Finally,the power allocation ratio between the secret signal and the AN signal was optimized to maximize the secrecy outage probability(SOP)constrained secrecy rate.Numerical results confirm that both the quality and security of the secret signal have been enhanced.Therefore,the proposed scheme is more suitable and reliable for security applications in interference networks.