Physical And MAC Layer Research For Fiber Grating Wireless Sensor Network

Wireless Sensor Network (WSN) is an integration of techniques including sensor, embedded computation, networking, wireless communication and distributed computation. The small sensor nodes can collaborate to test, sense, collect and process the information of monitored objects and transfer the processed information to user via multi-hop wireless communication. WSN is regarded as a way to realize "ubiquitous computing" and it has a wide range of applications, such as military, environment monitoring, traffic monitoring, smart building, etc. WSN becomes a new research area and has a bright future in application. Therefore, it's meaningful to make scientific researches on WSN.WSN is an intelligent system comprised of many wireless nodes, a complete embedded system, generally comprised of sensor module, process module, communication module and energy module. The sensor module, mainly comprised of sensors, is responsible for data collecting. In some sense, Fiber Grating Sensors become the best choice in some applications. We are to design a novel wireless sensor node by integrating FBG (Fiber Bragg Grating) sensors and WSN.Medium Access Control protocol, at the bottom of network protocol layer, controls the allocation of communication path, is a key factor of influencing the performances of network and becomes a research point for WSN. Currently, S-MAC (Sensor MAC), which introduces periodic listen/sleep scheme to save energy, turns out to be a research hot point. However, such protocol, just a frame, lacks of deep consideration and discussion for the listening time computation. In this paper, we propose a novel approach to design the listing time of S-MAC for WSN for the aim of saving energy on the basis of the analysis of monitoring area's traffic distribution model.The work of this paper mainly includes:1. Analyzing the sensing principle of FBG sensors; discussing demodulation principle and method; figuring out the frame of practical monitoring systems;2. Analyzing the merits, shortcomings and application scenery of FBG sensors; discussing the structure of wireless sensor nodes; designing a novel sensor node using FBG sensor; constructing a novel sensor network;3. Analyzing the current MAC research for WSN; mainly researching the schemes of S-MAC protocol; constructing the mathematic model of energy waste, latency and energy saving efficiency;4. Based on the above models and the monitoring area's traffic distribution model, proposing a novel approach to compute the listening time of S-MAC for WSN for the aim of saving energy;5. The performances of networks comprised of novel wireless nodes using FBG sensor are simulated and analyzed; performances, including energy consumption, latency and throughput of networks applying IEEE802.11 and S-MAC are analyzed by NS2;6. For the purpose of reflecting advantage of the optimized S-MAC, the performances including energy waste, latency and energy saving efficiency are analyzed by MATLAB; meanwhile, performances including energy consumption, latency and throughput are analyzed by NS2;At the last part of this dissertation, the whole work of the dissertation is outlined and the further research issues are discussed.