Design And Implementation Of Wireless Sensor Networks For Building Environment Monitoring

Building environment monitoring helps enhance indoor environmental quality control, safety precaution, and explore higher energy efficiency. There are many drawbacks in the traditional monitoring system, such as high cost of wiring and maintenance, and great damage to room's appearance. Wireless sensor networks which provide a new technique of information acquisition and processing, bring a novel way for building environment monitoring. However, according to the strong application relativity, a specific design is needed to meet the requirements and characteristics of building environment monitoring.There are many problems using the low-power, short-distance communication micro node in the building, so a well-designed sensor network architecture and data collection method are essential to collect building environmental parameters data successfully. Based on the background, the thesis studies and implements a wireless sensor network for building environment monitoring. The main contributions are as follows:1. Due to resource constraints, sensor nodes can not equip themselves with high-precision sensors. In order to improve the accuracy, multiple nodes are deployed within the same room, so the information collected by these nodes is highly redundant. Inspired by the clustering protocols like LEACH, we form all nodes in the same room into a cluster using a plain address allocation mechanism, and use a simple application-dependent data aggregation algorithm to achieve data aggregation within the cluster. This procedure can reduce energy consumption caused by the transmission of redundant information and prolong the lifetime of wireless sensor networks while keeping the same information quantity;2. A wireless sensor network with hierarchical structure is formed when using the clustering algorithm, and all the nodes in the networks are divided into three types based on their different responsibility: the sensor nodes for collecting building environment parameters data, the cluster head nodes for cluster management and the sink node for managing the entire network and collecting data from all the sensor nodes. The wireless sensor networks'data gathering algorithm is designed according to the networks architecture combined with the clustering mechanism, it uses a reliable inter-cluster routing protocol to establish the network data link, and a data link maintenance algorithm to balance the energy consumption of each node, avoiding network faults caused by hot spots;3. The hardware and software of sensor nodes are modular designed to meet the concurrent and collaborative characteristics of nodes'task, and a layered protocol model with cross-layer mechanism is used for the nodes'communication protocol. Finally, the in-situ deployment and performance testing results show that the wireless sensor networks achieves the application requirements well in the aspects of data collection and on-line monitoring.