Design And Implementation Of Multi-Radio Sensor Node System Based On ZigBee Technology

Wireless sensor network (WSN) is a multi-hop Ad Hoc network system that consists of a large number of low-cost sensor nodes which are deployed in the sensor field. The nodes exchange information with each other using wireless communication. The purpose of WSN is to sense, acquire, process the information of the objects in the area covered by the network cooperatively, and send information to the observer. Currently, one important aspect of the research of WSN is how to realize the acquisition, transmition and processing of simple environmental data such as temperature, humidity and light intensity on small-sized nodes with severely limited energy.With the changing of monitoring environment, simple data gathered by WSN cannot meet the comprehensive need of people. In order to get fine-grained and precise information, it is urgent to introduce multimedia such as image, audio and so on that is rich in information to the environmental monitoring activities. However, traditional single-channel 802.15.4 WSN cannot provide the bandwidth needed to transmit streaming multimedia data due to its features.In order to solve the problem, a multi-radio multi-channel approach is proposed by this thesis. This approach works by equipping each sensor node with multiple radios. By working on different orthogonal channels, the nodes can transmit and receive information simultaneously. Thus, the bandwidth spatial reuse is improved and the interference between links is reduced. Firstly, the design and implementation of multi-radio sensor node based on ZigBee technology is introduced. Secondly, a detailed analysis of the performance of the multi-radio node is presented. Then, experiments are carried out to measure the practical performance. Experimental results validate the distinguished node performance improvement achieved by using multiple radios. Lastly, channel assignment and routing strategy that are suitable for multi-radio multi-channel WSN are proposed. With the decrease of hardware cost of wireless radio transceivers and the development of technology, equipping each sensor node with multiple radios is becoming acceptable and has a broad prospect of application.