Fog-Based Bootstrapping and Failure Repair Protocols for Wake-Up Receiver (WuRx)-Based Wireless Sensor Networks

The Wake-up Receiver (WuRx) presents a promising solution for energy-efficient, low-latency, and reliable wireless sensor networks (WSN) for numerous applications. With the use of an always-on energy-efficient WuRx in addition to the main radio that is initially kept in sleeping mode, the energy of the sensor is preserved and the main radio is only woken up by the WuRx when it is required. While WuRx-based sensor networks offer numerous advantages, they encounter significant challenges during the bootstrapping and failure repair phases due to the sleeping state of the sensor's main radio. This limits its responsiveness and ability to effectively initiate or restore network functionalities. Also, the constrained range of WuRx exacerbates communication issues within the network, impeding seamless coordination and data transmission during critical phases. This paper aims to overcome these challenges by taking profit from the fog computing. We propose a novel fog-based bootstrapping protocol for indoor WuRx-based WSN. In our protocol, the network is divided into clusters each of which is managed by a fog node that orchestrates the bootstrapping process according to the nodes' rank. Furthermore, we present a novel fog-based failure repair protocol in which the fog node detects nodes and links failures and replaces in a time and energy-efficient manner the failed nodes and/or links with other alternatives to ensure continuity and reliability of communication within the network. We propose as well another failure repair strategy based on acknowledgment and specify what are the pros and cons of each approach. The performance evaluation of our bootstrapping and failure repair protocols has shown their time and energy efficiency and their adequacy in time-critical applications.