The Research On Wireless Sensor Networks MAC Protocol Base On Scheduling

Wireless sensor networks is a self-organizing networks constituted by many multi-hop sensor nodes, which has great potential applications in environmental protection, disaster monitoring and military defense and other areas. At the traditional network architecture, MAC layer protocol in wireless sensor networks network protocol stack occupy an important position, which determines the way of acquiring, possession and releasing channel between nodes.This thesis first introduces the characteristics and functions of the MAC protocol, channel accessing and mechanisms for resolving conflicts. Because of distributed processing and energy-constrained, based on implementing the basic functions, the MAC protocol of wireless sensor network also has to take into account the way of obtaining a longer network lifetime.The thesis introduces several wireless sensor network protocol based on competition and scheduling to resolves the problem of reducing idle listening, conflicts and overhearing. Because MAC protocol based on scheduling does not generate conflict on acquiring channel, this feature which can avoid idle listening is very suitable for requirements of energy-saving. This dissertation improved BMA protocol for the limit of channel utilization, especially when a small number of nodes required large amount of data transmission, time slot allocation can not meet the data transmission, and changing network traffic through real-time adjustment on time slot allocation and alternate channel possession. The improved protocol improves channel utilization, to save energy and prolong network lifetime.Finally, the improved protocol takes in account the conflicts of different clusters, avoids the conflicts through backoff mechanism, Theoretical Analysis and simulation shows that the efficiency of transmission has been enhanced.