Research On WSN-Based Measurement Network For Grain Depot

In recent years, with the rapid development of wireless sensor networks (WSN), the application of collect the information for environment monitor has been paid more attentions by researchers. WSN-based measurement network for grain depot is the sensor network that most sensor nodes are buried in the grain or deployed in the grain surface. Compared to using wired sensors technology for the measurement system in large-scale barns, WSN-based measurement network has several outstanding advantages in easy deployment, multi-parameter monitoring and easy upgrade. Research of WSN technology for the measurement system in large-scale barns has a great practical meaning to improve the quality and performance of monitoring. This paper mainly focuses on the study of energy-efficient data gathing protocol based on measurement network for grain depot. Firstly, according to the characteristics of grain storage, building the wsn-based measurement network topologies. Secondly, based on the network topologies this paper study of energy-efficient routing protocol to extend lifetime of the measurement network. The main contributions of this thesis are as follows:(1) To get the wireless sensor nodes'transmission distance which is buried in the grain, attenuation theory in grain and packet loss rate were used. Through experiments and analysis, the 780MHz RF attenuation in wheat and the data transmission distance is gained. It is helpful in nodes' deployment.(2) The sensor nodes deployment problem of WSN-based measurement network is explored. Based on the demand of monitoring large-scale barns, two network topologies for measurement system were proposed--WSN with temperature measurement cables and WSN with sensors. To evaluate the feasibility and the challenges of the first topology, some simulating experiments were designed. The results show that some methods need to be done to meet the network lifetime.(3) Aiming at ZigBee network for WSN applications, we firstly analyses the node energy consumption issues of AODV protocol and optimal energy routing mechanisms. Then to optimal AODV protocol for energy-efficiency usage, an improved routing algorithm, E-AODVjr, combining AODVjr with the node residual energy is proposed. E-AODVjr can reduce the packet delay with comparatively small in overload. The simulation experiment indicated that the performance of E-AODVjr protocol has remarkable improvement, and the life time of the network is extended obviously.(4) Investigates the currently clustering algorithms in wireless sensor networks,and then a clustering routing protocol LBCP combining the time synchronization protocol for environment monitor is proposed. In this new protocol, we introduce the time synchronization, load banlance, multi-hop mechanisms, and to avoid the inter cluster interference two methods are designed. Our simulation results shows that compared with the conventional LEACH protocol, the performance of LBCP protocol has remarkable improvement for data gathing networks, and the life time of the network is extended obviously. Using this protocol in measurement network for grain depot, we obtained meaningful simulation data.Based on the above achievements, we implement a data collection prototype based on LBCP and IEEE P802.15.4c wireless sensor nodes. We also describes time synchronization and TDMA schedule method detailedly. Our system is deployed in test Granary, experiment results show that all packets are successfully collected throuth Internet.