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为了实现在保证较低误码率的基础上延长网络寿命的目的,提出了基于混合译码放大转发(HDAF)中继策略的最优中继选择方案。构造了基于目的节点接收信噪比和网络寿命的中继选择的联合优化函数,实现了最优中继的选择。首先设定中继节点的接收信噪比门限,根据信噪比门限值将所有中继节点分为采用放大转发(AF)和译码转发(DF)中继策略转发的两种类型,然后分别计算两种类型的中继节点在目的节点的接收信噪比,最后根据中继选择的联合优化函数,合理选择最优中继。此外,理论推导了系统平均误码率的近似表达式。仿真结果表明,在相同条件下,与基于AF的中继选择方案相比,不仅在误码率性能方面有明显的改善,而且延长了网络寿命,提升了系统性能。
In order to achieve the purpose of extending network lifetime on the basis of ensuring a lower bit error rate, an optimal relay selection scheme based on hybrid decoding transcoding (HDAF) relay strategy is proposed. The joint optimization function of relay selection based on the destination node receiving SNR and network lifetime is constructed, and the optimal relay selection is achieved. Firstly, the threshold of received signal-to-noise ratio of relay node is set. According to the signal-to-noise ratio threshold, all relay nodes are divided into two types, which are relayed by AF relay and DF relay relay. Calculate the received signal-to-noise ratio of the two types of relay nodes at the destination nodes, respectively, and finally select the optimal relay based on the joint optimization function selected by the relay. In addition, the theory deduces the approximate expression of the average bit error rate of the system. The simulation results show that under the same conditions, compared with the AF-based relay selection scheme, not only is there a significant improvement in the bit error rate performance, but also the network lifetime is prolonged and the system performance is improved.