阻塞干扰下跳频通信系统差错控制

Error control for frequency hopping communication systems under man-made noise

为了解决传统差错控制方法的不足,结合跳频通信的特点提出了一种基于修正II型混合自动重传请求(ARQ)的高效率、低复杂度、低延时的差错控制方案.该方案从4个角度对跳频通信进行优化:(1)采用码率为1/2的可逆缩短BCH码做前向纠错,利用该码的可逆特性降低重传概率,同时利用信道的软信息做差错控制处理以提高系统增益;(2)新系统对重传数据包做等增益包合并,以充分利用信道的时间分集,降低噪声干扰;(3)采用训练序列做阻塞检测,丢弃人为干扰包;(4)采用BCH混合解码技术,实现复杂度和性能指标的良好折中.计算机仿真结果表明,新方案在中低信噪比区具有明显增益,适合用于工作在阻塞干扰下的跳频通信系统以实现数据可靠传输.

In order to overcome the drawbacks of traditional error control scheme （ECS） in the frequency hopping （FH） communication systems and achieve reliable transmission under man-made noise, this work proposed a modified type-Ⅱ hybrid ARQ based ECS, which is more efficient while with low complexity and low latency. The new ECS was optimized in the following four aspects. Firstly, invertible shortened half rate Bose-Chaudhum-Hocquenghem （BCH） code was used for error correction to reduce the retransmission probability. Meanwhile the channel＇s soft information was exploited to increase the system gain. Secondly, the new ECS combined the retransmitted packets according to equal gain criterion in order to exploit the time diversity and reduce the noise. Thirdly, a train sequence was used for man-made noise detection to remove the jamming. And lastly, the BCH code was decoded using a hybrid decoder to realize good tradeoffs between complexity and performance. Simulation shows that the proposed scheme outperforms the conventional counterpart with considerable gain in low to medium SNR regions and is suitable for FH communication systems under man-made noise.