A Research On Asynchronous MAC And Simulation System In Wireless Sensor Networks

As the extensive application of wireless sensor networks, improving the energy-validity of networks has been crucial to the research and design of wireless sensor networks. The MAC protcol also takes an important part in this area. As an experimental method, networks simulation plays an very important role in the research on wireless sensors networks. It can provide powerful supports on research, when some experimental condition can not meet because of the equipment, the node function, the deployment environment and the networks scale etc. This paper mainly opens out the research based on the MAC protocol of the asynchronous communication mode and the development of simulaton system, with the follow production:Firstly, this paper proposes a concept of asynchronous communicaton mode, based on the feasibility of low-power asynchronous communicaton module. In allusion to the possible effects on each-layer protocol and global performance of wireless sensors networks from the asynchronous mode, it has designed an asynchronous MAC protocol using peridical awake-sleep, partial time-synchronization and interactive-confirmation ACK mechanism etc. Then based on the data-correlation and actual-demand of wireless sensors networks, the peridical awake-sleep mechanism mainly include two different kinds of mechanism, which are sequential-awake and interleaving-awake. With the system simulation, experimental results show that the MAC mechanism is good at energy-saving in the low-ratio scene .Secondly, it has designed and developed a suitable simulation system for wireless sensors networks in order to meet its special demands. This system adopts C++ as programming language, which improves the simulation efficency and the network scale on simulation. It also adopts layer structure to implement the single node layered and define the function behaviors on each layer. In this system, one layer is independent from each other in order to improve the reuse rate of the module code. In addition, it integrates energy-consumption, time-delay, packet-loss models and adopts database as a backstage supporter to strengthen simulation function and capability of storaging and processing experimental data. If providing the configuration file, We can simulate without the platform, improving the portabillity. Finally, the results of three simulation experiments show that the system is a good experimental platform for WSNs, with the feature of modeling fast, remodeling effectively, complete function and more reliable experimental data.