基于部分可观测马尔可夫决策过程的水声传感器网络介质访问控制协议

针对水声传感器网络低带宽、高延迟特性造成的空时不确定性以及网络状态不能充分观察的问题,提出一种基于部分可观测马尔可夫决策过程(POMDP)的水声传感器网络介质访问控制协议.该协议首先将每个传感器节点的链路质量和剩余能量划分为多个离散等级来表达节点的状态信息.此后,接收节点通过信道状态观测和接入动作的历史信息对信道的占用概率进行预测,从而得出发送节点的信道最优调度策略;发送节点按照该策略中的调度序列在各自所分配的时隙内依次与接收节点进行通信,传输数据包.通信完成后,相关节点根据网络转移概率的统计量估计下一个时隙的状态.仿真实验表明,与传统的水声传感器网络介质访问控制协议相比,基于POMDP的介质访问控制协议可以提高数据包传输成功率和网络吞吐量,并且降低网络的能量消耗.

Medium access control protocol based on partially observable Markov decision process in underwater acoustic sensor networks

Concerning the problem of spatial-temporal uncertainty caused by low bandwidth and high latency as well as insufficient network state observations in UnderWater Acoustic Sensor Network (UWASN), a medium access control protocol based on Partially Observable Markov Decision Process (POMDP) for UWASN was presented in this paper. Firstly, the link quality and residual energy of each node were divided into multiple discrete levels for expressing nodes' state information. After that, channel access probability was predicted by receivers through the history information of channel state observation and channel access actions, and then the optimal channel scheduling strategy for senders was acquired. Senders communicate with receivers and transmit data packets in their time slots according to the assigned sequence from the optimal channel scheduling strategy. When the communication was completed, the states of next time slot of the related nodes were predicted based on the statistics of the network transfer probabilities. Simulation results show that the proposed protocol can improve the data packet transmission rate as well as the network throughput, and decrease the energy consumption.