| The sensor network is deployed by a large number of sensors and nodes.With its good sensory and transmission capacity,sensor network is widely used in the wild environment to collect data.How to ensure the long-term and high success rate of data transmission in this conditional network environment is the target and challenge of this thesis.The types of nodes used by the sensor network deployed in the wild environment including battery-powered sensor node(hereinafter referred to as active nodes)and energy harvesting technology node which obtain energy from the environment(hereinafter referred to as passive nodes).In this thesis,the two kinds of scenario were studied,the main contents are as follows:1.For the delay delay-tolerant sensor network which use active nodes,because of battery-powered nodes,the main challenge of the network’s long-term work is energy consumption.The existing network protocols in the wild environment applications exist many problems such as too large energy consumption of synchronization process,the collision phenomenon during transmission process and hidden terminals problem.These issues will increase energy consumption and decrease data transmission success rate,making people have to frequently replace the node battery otherwise the node will die.In order to solve these problems,this thesis proposes a Neighbor Selected Information Based Asynchronous MAC(NI-MAC)to reduce node energy consumption.Unlike the existing methods,the nodes in this protocol avoid the sending time of all neighbor nodes and hidden terminal nodes using sending decision table when they choose its own sending time.This strategy ensures that the node minimizes the energy consumption caused by the collision and improves the success rate of data transmission.The receiving time of the node is selected according to its own neighbor periodic table,so that the node can keep the sleep state in the absence of data reception to reduce the energy consumption.2.For the sensor network which use passive nodes,because the nodes can harvest energy from the environment,so energy consumption is no longer the only concerned factors in this type of network.Taking into account the energy consumption and delay comprehensively can make the node to obtain a longer life cycle while increasing the speed of data sending to the base station.The existing routing protocols used in the passive node network always take into account the energy consumption or delay performance respectively,thus this thesis presents the balance of Energy and Delay Opportunistic Routing protocol(EDOR)to balance the performance of energy consumption and delay.The protocol estimates the expected energy consumption value of the node by analyzing the node transmission process,so that the node chooses the neighbor node with low energy consumption as the forwarding candidate.When the final forward node is determined,this protocol makes a decision by considering the duty cycle information of the next hop neighbor node among candidate nodes.So that the sending node chooses the candidate node which will forward the data faster to reduce the delay,thus realizing the balance of energy consumption and delay performance.Finally,this protocol also reduces the number of unnecessary copies of data packets during the opportunistic routing process by designing a backoff strategy to achieve the singularity of the forwarding nodes.3.By using the OMNeT ++ platform to test the performance of energy and delay,the correctness of NI-MAC and EDOR protocols proposed in this thesis are verified by a large number of simulation experiments,and the performance optimization compared with the existing protocols. |
