Reliable network connectivity in wireless sensor networks for remote monitoring of landslides

Providing reliable communications in a remotely monitored large-scale deployment of Wireless Sensor Networks is a challenging task. In this paper, we deal with such a deployment to monitor a landslide prone zone where the nodes sense geological attributes essential for early warning. The deployment area is a hilly mountain with different demographic characteristics. Establishing network connectivity in this deployment site for real-time streaming of sensor data involves dealing with site specific challenges such as asymmetric links, dynamic network conditions due to rough weather, inadequate solar power, network fail-over and re-connection problem etc. Our deployment makes use of only a few number of relay nodes for connecting the wireless sensor network to a field management center through an IoT gateway. The field management center makes use of multiple fault-tolerant WAN networks to relay the data to a remote central data management center for deep data analysis and for generating early warnings prior to a catastrophic event. This paper provides insights into our experiences from successful deployment of a WSN system and reports real-time measurements taken in the field for ensuring network reliability. Evaluation of our system reflects that the network is able to provide reliable communication by providing a fail-over for streaming data with less than a minute to re-establish the connection and the gateway software is capable of handling heterogeneous sensor readings at a rate up-to 1700/s within a latency of 10 s while delivering the data to the data center. The system also achieves highly accurate time synchronization in the order of microseconds throughout the network.