A Study On Multi-Channel Scheduling For The Capacity Expansion Of WSN

Wireless sensor network is a new information sense and process technology, which incorporate sensor technology, embedded technology, distributed computing technology and so on. As a small,self-organizing,flexible,cheap network, It is widely used in many districts,for example, environmental monitoring, industrial control, medical health and so on. In the typical applications, as climate monitor for the forest and high-fidelity monitor of temperature for data center,the dimension of the network has reached1000nodes, and the density of node in the network is0.5per square meter. The interrupt between nodes, which is caused by wireless communication and many to one working pattern, affects the throughput and reliability of the entire network. So It is important to research wireless sensor network protocol with high capacity.Nowdays most of the network protocols are designed for small traffic network, the capacity of the network is low. And in the data center, the channel condition is bad, the network capacity will decrease further, so the network protocols can not reach the applications’requirement. Based on analyzing the multiple channel MAC protocol and route protocol for the wireless sensor network, combining the cross-layer design idea, this paper proposes a tree based multi-channel protocol TBMCP. It uses the coarse channel assignment method through assigning a channel for each subtree. It can reduce the channel switching frequency and communication frequency between nodes working on different channel, to balance the payload of each subtree and improve the throughput of the entire network. The main research content is listed as follows.(1) analyze the existed multi-channel MAC protocol and route protocol in the wireless sensor network, present the drawbacks of the multi-channel schedule.(2) Considering the feature of the wireless sensor network, research to design network protocol by adopting the cross-layer designing idea and propose a tree-based multi-channel protocol to improve the throughput of the entire network.(3) As the Tossim which is the simulation tool in the TinyOS, doesn’t support multi-channel simulation, this paper analyzes the system structure of the Tossim, introduces a new simulation event, and modifies related components to support multi-channel simulation. (4) Implement the multi-channel protocol in the Tiny OS System, and set up a real small network to test its performance. Then make a comparison with the single-channel protocol to present this multi-channel protocol can truely impove the entire network’s throughput. At last, use the extended Tossim to test the performance of the multi-channel schedule mechanism in TBMCP in the bigger network.