Research On Adaptive Energy-Conservation MAC Protocol Of Wireless Sensor Networks

Wireless sensor network (WSN) is a kind of multi-hop self-organizing network system, which consists of a large number of intelligent micro-sensor nodes through wireless communication. The characteristics of WSN are as follows:large-scale, dynamic, limited hardware resources, data-centered, energy-constraint, application-relevant and so on. The sensor nodes in WSN are usually battery-powered and consequently energy-constraint, and furthermore, it is not realistic to replace the battery in practical application, so energy-conservation is one of the essential issues of WSN. The energy of sensor nodes is mainly consumed for the idle listening, and the MAC protocol directly controls the wireless transceiver circuit, so the research on MAC protocol is very necessary to WSN because the energy consumption for idle listening can be conserved through the optimization of MAC protocols.The main contribution of this paper is realizing and optimizing the PMAC(Pattern Medium Access Control, PMAC) protocol based on the analysis and elaboration of it, achieving the purpose of the improvement of energy efficiency. First, by the study of the existing MAC protocols, PMAC can adjust the number of the wake-up slot and the sleep slot according to the network traffic is discovered. Then, on the basis of the fundamental theory, realize and optimize PMAC:present the slot allocation algorithm for PETF sub-frame, present the superior synchronization mechanism, refine the data transaction mechanism for PRTF sub-frame, add TMAC time-out mechanism and combine the PETF stage and synchronization stage into one. At last, simulate the improved PMAC and the original PMAC in NS2, the result demonstrate that the improved PMAC is superior in energy-conservation.