基于导频长度优化的安全传输方案设计

Secure Transmission Scheme with Optimized Pilot Overhead

考虑一个单发单收单窃听的通信场景,假设每一个节点都只装配单天线,在准静态块衰落信道下设计基于导频长度优化的安全传输方案。由于实际通信过程中用于信道估计的导频资源有限,发端不能完全获知主信道的瞬时信道状态信息,导致连接中断不可避免;同时考虑被动窃听场景,由于发端不能获知窃听信道的瞬时信道状态信息,因此安全中断不可避免。为保证传输的可靠性和安全性,提出一种基于系统中断性能的安全编码参数选择策略,得出保证安全传输的主信道链路条件。基于这一传输条件,设计了一种安全机会传输方案,并分析了系统的净安全吞吐量性能。通过最大化净安全吞吐量这一性能指标,进一步研究了在该安全传输方案下的最优导频长度问题。最后,仿真结果验证了理论分析的正确性。

The design of secure transmission scheme over a quasi-static block fading channel from a single-antenna transmitter to a desired single-antenna receiver is considered,with in the presence of passive single-antenna eavesdropper. A apractical scenario is assumed, where the transmitter can only acquire the statistical channel knowledge of the eavesdropper and the partial channel knowledge of the legitimate receiver via a finite amount of training overhead. To keep control of the outage events caused by the limited channel knowledge, a strategy to determine the wiretap code parameters under the outage constraints is firstly proposed, and then based on this, a necessary transmission condition to guarantee a positive secrecy rate is established. Aided by this transmission condition, an on-off-based transmission scheme is suggested and the secrecy throughput performance of the system analyzed. Meanwhile, with the net secrecy throughput as performance metric, the optimal pilot length that maximizes the secrecy throughput is examined. Numerical Simulations indicate the accuracy of theoretic analysis.