Relay-assisted Battery-aware Downlink Transmission in Indoor Industrial Environments

The focus of the thesis is to improve the energy efficiency in battery-powered relay networks oriented toward IIoT applications, focused on indoor factory scenarios. This topic shifts from battery-powered IoT networks destined for service types where broad coverage, low data rate and extended battery lifetime are expected. The channel conditions in factory scenarios were explored, focused on models derived from channel campaigns in industrial environments. Such explorations led to the contribution of a novel 3D model design based on raytracing approximations dubbed 3DSInFS, where channel conditions for some of the most common industrial scenarios are simulated. Statistical analysis of the results is used to generate realistic channel coefficients useful for system-level simulations of wireless IIoT networks. The second contribution is the design of a battery-powered, relay-assisted downlink protocol dubbed Cooperative Battery-Aware Localised Transmissions (CoBALT) aimed at industrial automation. The protocol finds an optimal placement of access points throughout the factory floor, bit allocation and downlink scheduling of data payloads to potential relay devices.