Research Of A Wireless Sensor Network MAC Protocol Based On Data Gathering Tree

Wireless sensor networks （WSN） are regarded as the most importanttechnologies which perform a great impact in human lives. Combing withcommunication technology, microelectronic technology and sensor technology, a newway to collect and process information is provided. Medium access control (MAC)protocol directly controls the way of nodes using the wireless channel, Because of thewireless sensor network’s distinct characteristics, the MAC protocol used intraditional wireless networks can’t be used in wireless sensor networks directly, sodesign MAC protocols to reduce energy consumption and latency becomes an urgentproblem in wireless sensor networks. Based on the requirement of both energy andlatency, an improved low-latency and energy efficient DMAC protocol was proposed.This article focuses on the data gathering tree structure, mainly completes thefollowing work:First, the main difference between WSN and traditional networks is proposed,The considerations to design MAC protocols are discussed, which include the networklifetime, energy consumption, end-to-end latency throughput and so on. The classicWSN MAC protocols are analyzed, the mechanisms used by the protocol and theirperformance to the network are discussed. The advantages and disadvantages ofvarious mechanisms are compared; the problems of latency and energy consumptionare analyzed.Second, based on the data gathering tree topology, the disadvantages of classicdata communication are analyzed. Based on this, to reduce network latency andenergy consumption, according to the staggered scheduling mechanism of datagathering tree, a new data transfer mechanism based on overhearing is proposed. Inthe transmission path, a packet can be a data to the next hop and can also be an ACKto the previous node. In this way, redundant packets and network transmission delayare reduced; the link usage and the energy efficiency of the node are improved, andensure reliable data transmission in wireless channel. The simulation results show thatthe improved protocol provides latency reduction and energy savings.Then, to balance the network traffic and prolong the network lifetime, accordingto the shortcomings of data gathering tree, the simulation show that when networktraffic is heavy, nodes have low depth in the tree topology have more packets totransfer and are more likely to crash, which resulting in packet loss. Because of thedata retransfer for collision have more energy consumption and network latency, this paper proposed a node sleep scheduling mechanism, using it to balance networktraffic. When the network is busy, the node turn off its radio to sleep, so it can reducethe packet’s conflict, balance network traffic and prolong network lifetime. Thesimulation results show that the improved protocol provides long network lifetime.Finally, at the end of this paper, there is a conclusion of the work has been doneand a plan of the future work.