Research And Design Of MAC Protocol For Digital Energy Integrated Sensor Network

With the rapid development of wireless communication technology,people have higher and higher requirements for wireless communication,whether it is traditional battery-powered or plug-in power supply.It is not enough to support people's peak requirements for the flexibility and sustainability of wireless communication.Therefore,Simultaneous Wireless Information and Power Transfer(SWIPT)technology came into being.We focus on the introduction of SWIPT technology on the basis of traditional wireless sensor networks to form a wireless sensor network with digital-energy-integrated.Based on this,we optimized the MAC layer protocol of the Digital Energy Integrated Network(DEIN),to extend the overall network lifetime,reduce invalid energy consumption,and improve the energy efficiency.The main research contents of this article can be divided into the following three parts.First,we designed a basic architecture of the digital energy integrated platform system and four digital energy division schemes based on the ZigBee protocol.Based on this,we performed a needs analysis survey and equipment selection,choose the frequency division scheme,used the mature ZigBee protocol and corresponding development toolkit for a pre-experiment.Based on the digital result of the pre-experiment,all parameters of the data transceiver and enrgy tansceiver are designed.Thus,we built a point-to-point wireless digital energy integrated system to realize the wireless energy supply and acquisition of terminal sensor nodes,which verifies the SWIPT technology can be effectively applied into the wireless sensor networks in the hardware system level.Then,based on the IEEE 802.15.4 protocol of the integrated wireless sensor network,a modified scheme of the superframe structure is proposed.The inactive phase of the traditional MAC layer superframe structure is deleted,and the time slot order of the superframe structure is adjusted,thereby,we can increase the number of time slots of downlink wireless tansmission and increase the capacity of downlink wireless energy charging.At the same time,we proposed a decision ordering formula for guaranteed time slots(GTS)in the Contention Free Period(CFP)of the network coordinator,add the remaining energy percentage,data change and data validity period into the decision range of GTS allocation,so that the nodes with less energy,large amount of data change and short data validity period will have higher priority for the CAP's GTS,thus we prioritize the energy-starved and digital-urgent nodes to communicate using CFP's GTS,reducing the energy interrupt rate,extending the overall network lifetime,and improving the overall network throughput.Finally,we focused the superframe's Contention Access Period(CAP),designed a selective communication competition algorithm for digital energy integrated network.A learner is built and trained by support vector machine model and historical dataset,calculated the competitive reporting baseline value and the GTS application baseline value,to guide the terminal nodes' selective competition reporting and selective GTS application,reducing the meaningless communication attempts and energy waste.Meanwhile,we optimized the CAP's Carrier Sense Multiple Access with Collision Avoid(CSMA/CA)protocol's backoff algorithm,designed a backoff window calculation formula which introduced the remaining energy percentage of the terminal nodes,aiming at reduce the backoff time of energy-sufficient nodes while extend the backoff time of energy-starved nodes,from that we can reduce the energy interrupt rate,extend the network lifetime,and improve the overall network throughput.This paper introduced SWIPT technology into the traditional wireless sensor network effectively and reasonably,and optimized and innovated the traditional MAC layer protocol.We focus on the macro superframe structure and CAP for optimization,increase the capacity of wireless energy supply,reduce the meaningless energy waste and energy interrupt rate,extend the network lifetime,and correspondingly improve the overall communication throughput.