一种基于RB-HARQ安全传输技术的吞吐量最大化方法

A method for the maximum throughput of the RB-HARQ implemented in secure transmission

在基于可靠度混合自动重传技术(Reliability-Based Hybrid ARQ,RB-HARQ)的物理层安全编码中,提出一种根据信道条件选择最优重传比特数目的方法,该方法能够在保证安全性的条件下实现吞吐量最大。在RB-HARQ技术中,接收端将码字比特按照可靠度信息大小进行排列,将最低可靠度的比特重传给发送端。为了最大化吞吐量,利用密度进化算法和软合并的方法计算出相应节点的信息概率密度,通过近似得出理论误比特率,在此基础上从理论上得出最佳重传数目方案。仿真结果表明,所提算法与传统的RB-HARQ算法相比,在保证安全性和可靠性的条件下,显著提高了吞吐量,并且验证了理论分析的正确性。

This paper proposes a way to obtain the maximum throughput under the condition of ensuring the security in the reliability-based hybrid automatic repeat-request（ RB-HARQ） aided physical-coding scheme. It adopts the channel condition to choose the optimized size of retransmissions. In the RB-HARQ,the receiver feeds back the indices of the bits ranked according to reliability,which is measured by the absolute value of the log-likelihood ratios（ LLR）. This scheme utilizes density evolution and chase combing to calculate the message density probability,which helps obtaining the approximate BER in theory. On this basis,the optimized sizes are selected to be applied in the set of simulations. The results show that the performance in theory agrees with the performance in practice,and the proposed scheme enhances the efficiency and ensures low BER.