Adopting Multi-RAT Communication in Healthcare Internet of Things: Taxonomies, Open Issues, and Research Directions
Recent advancements in Internet technologies, including Network Function Virtualization (NFV) and Software-Defined Networking (SDN), have driven transformative changes across multiple sectors, notably in e-Healthcare, smart cities, industrial automation, and intelligent transportation systems. Central to this evolution is the Internet of Things (IoT), which enables pervasive sensing, real-time data collection, and intelligent decision-making. In particular, the Healthcare IoT (H-IoT) domain has seen rapid growth, supporting critical applications such as telemedicine, remote diagnostics, and continuous patient monitoring. These applications impose stringent communication requirements, low latency, high reliability, scalability, and efficient bandwidth utilization, that challenge conventional network infrastructures. Emerging communication technologies like 5G and beyond aim to address these demands through features such as ultra-reliable low-latency communication (URLLC). However, the potential of multi-Radio Access Technologies (multi-RAT) to complement these efforts remains underexplored, particularly in dynamic and heterogeneous H-IoT environments. This paper revisits the H-IoT literature, focusing on multi-RAT adoption, which holds the potential to enhance communication capabilities significantly. By analyzing the current state of H-IoT implementations and identifying gaps in the literature, this study highlights the benefits of multi-RAT technologies and proposes a dual-stage approach to integrate these technologies effectively. This approach includes a comprehensive review of existing technologies, followed by a presentation of new research directions aimed at exploiting the underutilized potentials of multi-RAT in the H-IoT domain. Through this work, we aim to inspire further research and practical applications that harness the full capabilities of multi-RAT, thereby advancing the field of healthcare IoT.