The Research And Application Of Power Transfer Node In Wireless Sensor Network

Wireless sensor network(WSN)in today's society has been used widely,but a variety of factors limit the development and application of wireless sensor networks,one of the most important limiting factor is that the carrying energy in the sensor node is limited and can not be replenished.Sensor nodes can only be supplied by energy-limited battery and will be in the unattended state of work for a long time,so it is impossible to add energy through the replacement of the battery.To extend the life of a wireless sensor network,capturing energy from the surroundings is an effective way.At present.the main uses of capturing energy from the environment are temperature,pressure or vibration,electromagnetic energy and solar energy,etc.The use of electromagnetic waves to obtain energy and transmission of energy technology is relative with the wireless energy transmission(Wireless Power Transfer,WPT)technology.Energy and information are transmitted through the radio waves,the way to provide energy to the sensor node is that the energy base station radiates through the microwave far-field.Energy base station in the long-distance transmission of energy will be attenuated quickly,and the base station can note be constructed repeatedly in a region from the aspects of the hardware configuration,construction cycle,location selection and construction costs,etc.Therefore,a node with a simple structure and capable of amplifying the electromagnetic wave power is needed to solve the problem that the energy loss in the transmission process is large and the transmission distance is limited.In order to solve this problem,this paper proposes the introduction of wireless power transfer node(WPTN)to try to increase the wireless energy transmission distance and energy transmission efficiency of energy base station.The so-called transit node is essentially a device that emits an electromagnetic wave from an energy base station to perform energy replenishment at the relay node to amplify the transmit power,similar to a power amplifier in a wireless communication,thereby it can increase the instantaneous power received of the sensor node to satisfy the daily work needs and to extend the WSN work life cycle.In order to study the problem of transit node energy supply in WSN,the basic structure unit and energy transfer model of wireless energy relay node are described.The power amplifier in analog wireless communication system is used to increase the signal strength,his paper proposes to use the way of enlarging electromagnetic wave power by transfer node to amplify the way the electromagnetic waves transmit power,and thus increase the energy received by the destination node.Because of the different position of the transit node,the instantaneous power of the energy base station is different,and the power of the transmission is different,and the energy loss in the transmission process also changes with the transmission power.Therefore,the transit node is applied to where are only one energy base station and a work node in the simple energy transfer model and its possible influencing factors were studied.Through the simulation and analysis,it is concluded that the energy transfer efficiency ratio is lower when the transmission base of the energy base station and the working node is constant and the transmission power of the energy base station is constant.As the transit node approaches the energy base station or near the work node,the energy transfer efficiency ratio increases.This indicates that the energy supply of the working node should be increased when the working node is far away from the energy base station and the received energy can not meet its normal operation.The transit node should be introduced at a distance from the energy base station.In order to study the practical application of transit nodes,this paper introduces the energy base station and transfer node in the wireless sensor network,and proposes a transfer node energy supply protocol in the wireless sensor network.The energy coverage ofthe sensor node and the survival rate of the sensor network node were simulated.Through the comparison and analysis,it is found that the energy coverage and survival rate of the wireless sensor network after the introduction of the transit node energy supply agreement has been improved remarkably,which prolongs the working time of the node and effectively solves the current situation of the sensor network energy shortage.