Studies And Simulation Of Adaptive Asynchronous MAC Protocol For Wireless Sensor Networks

Wireless sensor network is a hot research field, which attracts more and more attention currently. It organizes network through wireless communication by a large number of randomly deployed sensor nodes and acquires a variety of environmental information. And it has a wide range of application in different areas.Medium Access Control protocol determines how to use the wireless channel and it is responsible for allocating the communication resources. It is one of the most important basic protocols which determine the overall network performance. Meanwhile, it directly manipulates RF module which consumes the most energy in sensor nodes. So it has an important significance to study MAC protocol.Concerned that wireless sensor network has uneven traffic load in most applications and in order to save energy consumption, this thesis studies and improves asynchronous MAC protocol for wireless sensor networks. The main work and contributions are as follows:1﹑Classifies and summarizes the existed protocols from different angles. What’s more, elaborates the mechanisms and advantages and disadvantages of these typical protocols.2﹑Models the performance of three typical asynchronous MAC protocols in low traffic conditions. Analyzes and compares the performance according to the unified parameters, which contains average delay, idle listening energy consumption and node’s energy consumption.3﹑Considered that the performance of asynchronous MAC protocol is poor in high traffic networks since sensor nodes turn to sleep directly after listening the data. This thesis makes some useful attempts in order to improve the performance.The basic idea is to let the node continues to listen after receving data and adjust the listening time adaptively according to network traffic. Then presents the energy consumption model and derives relationship between optimal listening time and network traffic. It also analyzes the nodes’data flow model theoretically.4﹑The improved adaptive asynchronous protocol is achieved on the network simulation tool NS2. Three experiments are carried out through the eatablishment of network simulation scenaries. The results show that the performance of the improved protocol is almost the same as traditional protocol in low traffic conditions. However, the network performance is improved significantly in high traffic conditions.