6G Beyond Radio: From Connecting Devices to Sensing the World

Future sixth-generation (6G) wireless networks are expected to evolve beyond traditional communication infrastructures and incorporate native sensing and environmental awareness capabilities. While previous generations primarily focused on connectivity metrics such as data rate, latency, and radio-frequency (RF) coverage, emerging applications increasingly require networks that can perceive physical environments and support context-aware decision making. This paper introduces the concept of sensing coverage as a complementary performance dimension to conventional RF coverage in sensing-enabled wireless systems. Within this perspective, a unified 6G vision is presented in which wireless infrastructure operates as a distributed sensing platform enabled by integrated sensing and communication (ISAC). The complementary paradigms of Network for Sensing, Sensing for Network, and Sensing-as-a-Service are systematically analyzed to clarify their roles in sensing-centric wireless architectures. The paper further reviews heterogeneous sensing technologies including cellular sensing, Wi-Fi sensing, visible-light communications (VLC), non-terrestrial networks (NTN), terahertz (THz) communications, and reconfigurable intelligent surface (RIS)-assisted sensing, illustrating how these technologies jointly enable multi-layer sensing coverage. In addition, quantitative foundations and performance metrics for sensing coverage are presented, and an illustrative evaluation is provided to highlight the fundamental differences between RF communication coverage and sensing coverage. Finally, the roles of AI-native intelligence, digital twins, and sensing-oriented service models are discussed in the context of sensing-enabled 6G networks. The presented framework provides a structured view of the emerging sensing-centric 6G ecosystem and highlights key research directions for future wireless systems that jointly integrate communication, sensing, computation, and intelligent services.