Enhancing the Performance of 802.15.4-Based Wireless Sensor Networks With NB-IoT.

Multihop low-power wireless communication is a key feature of wireless sensor networks (WSNs). Although with a lot of efforts, the performance of multihop WSNs in practical deployment could still be unpredictable and unsatisfactory, such as high packet transmission latency and short network lifetime. Narrowband Internet of Things (NB-IoT) is an emerging cellular technology for providing wide-area coverage. In this article, we investigate the possibilities of deploying 802.15.4 and NB-IoT equipped sink nodes (i.e., gateways) into existing WSNs to achieve the predictable and improved performance in terms of end-to-end reliability, end-to-end latency, and network lifetime. To calculate these key network-wide metrics, we propose a hybrid analytical model for 802.15.4 and NB-IoT traffic, taking the new features of NB-IoT into account. Based on the established model, we formally consider two types of fundamental problems, i.e., the minimum gateway deployment and the optimal kappa-gateway deployment. We implement our framework and extensively evaluate it in the realistic as well as synthetic WSNs. Results demonstrate that our approach can provide significant performance gains, e.g., the network lifetime can be extended by 37.4%-80.3% by deploying only one sink node. Compared with a state-of-the-art method, our approach improves the network lifetime by 12.6%-31.8%.