Research On Cluster-Based TDMA Scheduling For Wireless Sensor Networks

Wireless sensor network is composed of many small, self-organizing and massive sensor nodes which are located in the monitoring region. It has been becoming an important technology for information detection and Internet of Things (IOT). Media Access Control (MAC) protocol decides the wireless communication resource allocation and the energy consumption of nodes. So the research on the energy-efficient MAC protocol is one of the focuses in wireless sensor network which is constrained by network energy.In this thesis, the cluster-based Time Division Multiple Access (TDMA) scheduling mechanisms in wireless sensor network are researched. Firstly, the WSN clustering routing technology is introduced, and several clustering routing algorithms are simulated based on a WSN clustering network simulation model which is established by OMNET++ simulator.Secondly, this thesis analyses and simulates the fixed slot size TDMA scheme and the Low-energy Adaptive Slot Allocation(LASA) TDMA scheme which uses the dynamical slot allocation method according to the data size of sensor nodes. LASA scheme is more efficient than the static slot scheme, especially in eliminating the slot idle time and improving the resource utilization. The simulation results show that the LASA algorithm significantly reduces the node energy consumption, enhances the network throughput and extends the network lifetime.The LASA scheme is superior than the static slot TDMA scheme, but it still does not resolve the problems of the blind zones of network detecting caused by the edge nodes dead early due to the energy exhaustion, and the excessive control packets transmitted when nodes are active without data sending or receiving. Based on the LASA scheme, an improved LASA algorithm is proposed, in which a scheme of the alternative cluster head is introduced to balance the network energy consumption and the query mechanism is used to reduce the request control packets. The simulation results demonstrate that the modified LASA algorithm outperforms the static slot scheme and the LASA algorithm in balancing the network's energy, prolonging the network's lifetime and enhancing the network throughput.