When the concept Internet of Things (IoT) first emerged, its additional sensing capabilities were identified as a critical paradigm shift from computer networks. Sensing and communications have therefore been indispensable in the design and implementation of ubiquitous IoT devices, ranging from autonomous vehicles, wearable electronics, to drones and satellites. However, in the traditional IoT processing pipelines, sensing and communication capabilities are individually accomplished by the sensing-followed-by-communication mechanism, which will neglect the cross-system cooperation and mutual assistance.

The observations above have instigated contemporary research inquiries into the realm of Integrated Sensing and Communications (ISAC), which aims to jointly design, optimize, and coordinate sensing and communication functionalities to enable information sharing or mutual assistance. This technology can achieve its functions by sharing hardware and spectrum resources and combining signal processing strategies. On the one hand, the integration of sensing capabilities and wireless communication capabilities can not only give sensing capabilities to ubiquitous IoT devices, but also reduce costs and facilitate faster deployment. On the other hand, the real-world measurement, such as geographic relationship of communicating IoT devices, can be extracted and inferred from multimodal sensory data, which can be employed to proactively allocate wireless resources.

Endowing wireless sensing into current communication devices fosters a variety of innovative IoT applications, including but not limited to, human sensing (activity, gesture, vital sign, e-health, and intention), environmental monitoring, vehicular network, enhanced localization, and tracking, as well as proactive resource allocation to support next generation cellular IoT. For example, the unprecedented large-scale IoT network can realize city-level weather monitoring with the analysis of downlink and uplink path loss of the wireless channel, which benefits various smart city-related applications. Considering that close relationship between the echoes reflected by the human body and its movement, IoT devices can further recognize the behaviors in indoor environments, greatly improving our understanding of eHealth. This Special Issue (SI) discusses the disruptive revolution in IoT architecture necessitates a reconsideration of the designs of existing IoT devices concerning fundamental tradeoffs and limits, processing technologies, information extraction, hardware integration, and learning principles. Additionally, the emergence of new challenges to public security and privacy requires attention. Hence, in the era of IoT, it is highly demanded to conduct swarm and ambient intelligence relying on advanced network protocols as well as the exploitation of such an enabler. In this special section, we solicit high-quality original research papers on topics including, but not limited to: