基于长延时信道的水下传感器网络中继选择及功率分配优化算法

针对水下传感器网络(UWSN)中水声信道衰落特性随时间-空间-频率随机变化的特点，在此提出利用中继协作网络获得分集增益从而提高水下网络通信质量的水下协作网络模型。基于该协作模型，提出了一种基于信道增益和信号延时双指标最佳中继评价标准，并提出了基于该标准的最佳中继选择算法与基于最小误比特率准则的功率分配算法。仿真结果表明，相比于传统最佳中继选择算法，传输延时降低约16.7%；相对于等功率分配，该算法在典型场景下使误比特率降低1.81dB。

Relay selection and power allocation optimization algorithm based on long-delay channel in underwater wireless sensor networks

In order to deal with the channel fading in Underwater Wireless Sensor Networks (UWSN) changing randomly in time-space-frequency domain, underwater cooperative communication model with relays was proposed in this paper to improve reliability and obtain diversity gain of the communication system. Based on the new model, a relay selection algorithm for UWSN was proposed. The new relay selection algorithm used new evaluation criteria to select the best relay node by considering two indicators: channel gain and long delay. With the selected relay node, source node and relay nodes could adjust their sending power by the power allocation algorithm which was based on the principle of minimizing the bit error rate. In a typical scenario, by comparing with the traditional relay selecting algorithm and equal power allocation algorithm, the new algorithm reduces the delay by 16.7% and lowers bit error rate by 1.81dB.