A study on energy-efficient tree routing protocol based on link quality metrics for remote air environmental monitoring sytem

The multi-hop routing is an indispensable technology for reliable data transmission between sensor nodes in wireless sensor networks. However its realization is very challenging due to various characteristics of wireless sensor networks such as self-organizing, limited resources, data centric routing and others. These characteristics distinguish them from conventional communication and wireless ad hoc networks. This paper proposes a new tree routing protocol named as CLQM-TR (Critical Link Quality Metrics based Tree Routing) to improve the performance of remote air environmental monitoring system in tunnels. Furthermore we measure the propagation characteristics of the ZigBee radio signal based on IEEE 802.15.4 PHY/MAC in indoor communication environments. As a result of critical LQI and RSSI thresholds for reliable and efficient data delivery were deduced experimentally. The superiority of the CLQM-TR protocol was demonstrated in a real world. The newly introduced routing method will be used for various applications in wireless sensor networks.