基于无线携能通信的传感云系统Sink节点最优能效策略

Optimal energy efficiency optimization strategy for SWIPT-enabled sensor-cloud system

无线携能通信能够提升传感器网络的能量效率和资源复用率,然而当前研究均优化无线携能通信参数以实现系统增益,忽略了信道质量变化对系统能量效率的影响.为了解决该问题,针对无线携能通信的传感云系统,提出基于最优停止理论的Sink节点能效优化策略.首先设计下行无线携能通信、上行信息传输的工作时序,其中下行阶段Sink节点采用机会调度策略,选择信道质量较好时刻开始下行链路传输.Sink节点能效定义为系统所实现的上行吞吐量与下行能耗之比.继而基于最优停止理论,建立Sink节点能效最优化问题并证明该问题存在最优停止规则.最后设计最优能效算法求解Sink节点最优下行无线携能传输时刻,从而制定相应的能效优化策略.通过仿真实验验证最优能效算法的有效性与性能,同时通过不同策略的对比验证所提策略在提升Sink节点能效方面的优势.

Simultaneous wireless information and power transfer(SWIPT)can improve the energy efficiency and resource reuse rate of sensor networks.However,current studies optimize the parameters of SWIPT to achieve system gains,ignoring the impact of channel quality changes on system energy efficiency.In order to solve this problem,this paper proposes a Sink node energy efficiency optimization strategy based on the optimal stopping theory for the SWIPT-enabled sensor-cloud system.First of all,the schedule sequence of downlink SWIPT and uplink information transmission is designed.In the downlink phase,the Sink node adopts the opportunity scheduling strategy and selects the time when the channel quality is good to start the downlink transmission.Sink node’s energy efficiency is defined as the ratio of uplink throughput and downlink energy consumption realized by the system.Then,based on the optimal stopping theory,the problem of Sink node energy efficiency optimization is formulated and the existence of optimal stopping rules is proved.Finally,the optimal energy efficiency algorithm is designed to solve the optimal downlink SWIPT time of the system,so as to realize the optimal energy efficiency strategy of the sensor-cloud system.The effectiveness and performance of the optimal energy efficiency algorithm are verified by simulations,and the advantages of the optimal energy efficiency strategy are shown on system gains by comparing with other three strategies.