| In recent years, traffic problems attract concern and attention of the whole society with the rapid development of road traffic. Intelligent road, combined with the vehicles, road, and drivers, is an important part of intelligent transportation system (ITS). However, the traditional technologies and equipment still have deficiencies in common use. Since wireless sensor networks (WSN) has the features of wide coverage, convenient installation and maintenance, collecting data, distributed collaboration, etc., those WSN applications in ITS become a hot topic in recent years. Today, it is evolving into the "Internet of Things", and the "Car of Networking". Lulea University of Technology at Sweden proposed "Intelligent Road Mark System (IRMS)" in their intelligent road (iRoad) project. IRMS bases on WSN technologies, which makes use of Mulle as hardware platform, and TinyOS as software platform. Traffic information acquisition is realized by IRMS on the road of European E4 hightway. The experiment results reveal that intelligent road mark is effective to monitor vehicles. However, energy consumption is a key technical issue that hinders the application. In this thesis, our research purpose is to maximize the system lifetime with energy conservation technologies. We focus on power management, energy conservation strategy, control algorithms, and measurement device. Main content and innovations are as follows:1. Research on energy distribution and dynamic power management. Energy distribution research is a key premise of controlling energy consumption. This thesis utilizes the energy consumption measurement device to monitor the energy consumption of three main components in a node, and draws the comparison chart based on the results. Most of literatures mainly concentrate on the energy consumption of communication. However, our experiment result reveals that the energy consumption of sensors and micro-controller can not be ignored. From the sensors, micro-controller and transceiver, we take into account their energy consumption and build resource mapping and scheduling model in TinyOS. This model realizes a dynamic power management and can reduce the waste of energy when any component is idle.2. Research on energy conservation strategy and dynamic energy conservation strategy framework. Based on the proposed energy consumption distribution model and vehicle detection on the road, we present a dynamic energy conservation strategy combined with signal processing, low power listening and sensor activation rate. The dynamic energy conservation strategy, which can improve energy efficiency and reduce energy consumption, is demonstrated on the MicaZ platform. Finally, a formula is presented to describe the dynamic enrgy consumption of a node.3. The energy consumption consensus control theory and methods of multi-node collaboration. Sensor nodes are collaborative to finish tasks. Collaboration not only improves the accuracy, but also reduces overall energy consumption. Algebraic graph theory is used to describe the information interactive relationship among nodes. From the information interactive graphy, we establish information interactive map and information interactive matrix. Through sharing energy consumption information, the energy consumption consensus algorithm is proposed to control the collaboration of nodes so that collaborative nodes can keep energy consumption balance. Simulation results reveal that the algorithm is effective and energy conservation and this work can extend the lifetime of system.4. Real-time energy consumption monitoring. WSN energy consumption analysis has still a shortage through investigation that current research mainly depends on simulation. We propose to establish WSN real-time energy consumption monitoring platform in actual environment. Smart, precise, and mobile devices are developed to monitor node energy consumption, which will not affect nodes'normal working. The characteristics of this device make it suitable for the real environment. |
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