Research On Energy-saving Technology Of Wireless Body Area Network

In recent years,social problems such as the obvious trend of an aging population,the rapid rise in the number of patients with chronic diseases,the shortage of medical resources,and the tight relationship between doctors and patients have become more and more serious,which have seriously hindered the development of society and reduced people's quality of life.Wireless Body Area Network(WBAN)is a human-centered wireless sensor network with short distance,low power consumption and reliable transmission.By deploying biosensors on the body surface or body of the human body,various physiological information of the human body can be continuously monitored,which has broad application prospects in telemedicine.However,in WBAN,the size of sensor nodes and battery capacity are strictly limited,each node is deployed in the body or surface of the human body,and frequent battery replacement may increase the discomfort of the human body and even cause secondary trauma.Therefore,for the energy limitation of the node,not only should the system energy consumption be reduced to save energy,but also other power supply methods should be considered to ensure the long-term operation of the node.In addition,the sensor nodes are pre-installed at designated locations;in the process of data transmission,due to the shadow effect of the human body and the multipath effect caused by the change of the human posture,the number of retransmissions and the delay are increased,and the overall performance of the network is seriously affected.The information collected by the sensor nodes is usually related to the patient's life safety,so the reliability of WBAN data transmission must be improved.Based on the above problems,in order to realize the energy saving of WBAN,this paper mainly conducts the following research from improving life and reliability of the network:In the first chapter,a Routing Protocol Based on Energy Harvesting and Link Aware(EHLA)is designed to improve network energy efficiency and data transmission reliability.On the one hand,the introduction of energy harvesting technology provides energy to sensor nodes that are deficient in resources,which helps to solve the problem of sensor batteries that are deficient in energy and not easy to replace.On the other hand,the optimal next-hop forwarding node and the optimal path from the data to the Sink node are obtained after establishing a multi-objective cost optimization model consisting of the remaining energy of the sensor,the link quality,and the distance between the nodes.Simulation analysis has shown that compared with those of the existing EVEN and ELRW protocols,the network life of the protocol is significantly increased,the energy consumption and packet loss rate of the nodes are effectively reduced,and the data transmission reliability of the network is increased.In the second chapter,an Energy Management Strategy Based on Energy Harvesting and RI-MAC protocol synergy(EHRI-MAC-EM)is designed to further improve the energy efficiency of the network.On the one hand,three thresholds are added to the remaining energy level of the battery,each threshold corresponds to a different working mode,and the node is ensured to meet different business needs at each energy level.On the other hand,a dynamic low duty cycle mechanism is adopted.When the node has no transmission task or the remaining energy is insufficient,the sleep state is activated.During this period,the node with insufficient energy may replenish energy until the remaining energy reaches the threshold at which the node can work normally and switch to the active state.In the active state,the node can calculate the next sleep duration according to its remaining energy,so that the dynamic management of node energy can be achieved.Simulation analysis has shown that compared with that of the RI-MAC,the nodes of EHRI-MAC-EM can collect the energy of the surrounding environment to charge,and the network life is effectively increased.In addition,a dynamic management strategy is adopted for the energy of the nodes;at different packet transmission frequencies,the network delay is greatly reduced;finally,energy saving is achieved.