Research On Opportunistic Routing Protocol In Energy Harvesting Wireless Sensor Networks

Energy harvesting wireless sensor networks(EH-WSNs)is composed by a large number of energy harvesting sensor nodes deployed in the detection region,which is a self-organized multi-hop network formed by the wireless communication.EH-WSNs can harvest energy from the ambient environment.Thus,EH-WSNs removes the limit of battery power,and has better performance and wider application.Opportunistic routing protocol can utilize the broadcasting and time-varying nature of the wireless channel.By selecting the forwarding set for opportunistic packet forwarding,it can effectively reduce the delay and packet loss rate.In this thesis,we study the opportunistic routing protocol in EH-WSNs.In EH-WSNs,in order to use energy harvest from environment efficiently,nodes need adjust the duty cycle or transmission power dynamically.To reduce the delay and improve delivery ratio in packet transmission,EH-WSNs can increase wake-up time or link quality appropriately.However,in order to adapt to the network characteristics,we need make some improvements in opportunistic routing protocol:In forwarding set selection scheme,we needs to update the members and priorities of forwarding set dynamically.In energy management scheme,we need to make use of energy harvested from the environment,and accurately adjust the duty cycle or transmission power of nodes.In this thesis,we propose two novel opportunistic routing protocols for dynamic duty cycle and dynamic transmission power scenarios respectively.(1)This thesis designs an opportunistic routing in EH-WSNs with dynamic duty cycle(ORDDC).In this scenario,each node can adjust the duty cycle dynamically.Thus,for the sending node,the number and membership of the waking neighbor node may change dynamically,and it is difficult to know the rule by calculation.ORDDC can help nodes to get the duty cycle of neighbors by information exchange,and update the members and priorities of forwarding set,which reduce the delay and packet loss ratio.On the other hand,ORDDC can adjust the duty cycle accurately,which can balance the energy acquisition and consumption.Simulation results demonstrated that ORDDC can significantly reduce the end-to-end delay and improve the packet delivery ratio in EH-WSNs.(2)This thesis designs an opportunistic routing in EH-WSNs with dynamic transmission power(ORDTP).In this scenario,each node can adjust the transmission power dynamically.However,the transmission power may affect the link quality and transmission cost.Thus,for the sending node,the transmission cost of selecting the same node as the next hop may change dynamically,and it is difficult to calculate its rule.ORDTP can help sender to estimate transmission cost accurately by collecting information of neighbors,and update the forwarding set in time.ORDTP adopts a new packet forwarding scheme,which can stabilize the number of nodes actually participating in forwarding.On the other hand,ORDTP can adjust the transmission power accurately,which can balance the energy acquisition and consumption.Simulation results demonstrated that ORDTP can significantly reduce the end-to-end delay,improve the packet delivery ratio and reduce the packet redundancy ratio in EH-WSNs.There are some similarities in the design of two protocols:Both protocols can make full use of the energy harvested from environment,and adjust the communication parameter of node dynamically.Both protocols can update the forwarding set in time,and adopt the same transmission model and information interaction mechanism.There are some differences in the design of two protocols:The communication parameters in two protocols are different,and the adjustment schemes are different.The forwarding set selection schemes in in two protocols are different,and the metric designs are different.The packet forwarding schemes in two protocols are different,and the applicable scenarios are different.