Energy, Scalability, Data and Security in Massive IoT: Current Landscape and Future Directions

The Internet of Things (IoT) has emerged as one of the most transformative paradigms of the 21st century, driving the digitalization of industries, cities, healthcare, agriculture, and critical infrastructure. Unlike conventional networks, which connect a relatively small number of powerful end systems, IoT ecosystems consist of massive numbers of heterogeneous, resource-constrained devices generating continuous, real-time data streams. Forecasts suggest that the number of connected IoT devices will exceed 30 billion by 2030, with many deployments involving millions of devices within a single smart city or industrial environment. This unprecedented density and heterogeneity of devices introduce fundamental challenges that go beyond the scope of traditional communication networks and distributed systems.