Integrated sensing and communications (ISAC) is a new enabling technology that has emerged as a result of recent advancements in solid-state circuitry and wireless communication, as well as the high needs of sensing capability. Compared with specialized sensing and communication functions, the ISAC has two primary advantages: 1) Integration gain to effectively use crowded hardware and/or wireless resources, and even more intriguingly, 2) Coordination gain to achieve mutual aid or balance dual-functional performance. As a result of ISAC, the ubiquitous IoT architecture is undergoing a paradigm change. The communication and sensing layers are gradually merging to form a new layer called the signaling layer. In this work, we first try to define ISAC, then we examine the different driving factors and provide some new application cases. Next, we provide a number of significant advantages in the IoT era to further enhance our grasp of the signaling layer. We categorize currently popular ISAC systems according on the levels at which integration is used. Ultimately, a number of possibilities and problems are noted. With this overview essay, we intend to provide new researchers with a good foundation and an overview of the current state of ISAC-related achievements.

Integrated sensing and communications (ISAC) is a new enabling technology that has emerged as a result of recent advancements in solid-state circuitry and wireless communication, as well as the high needs of sensing capability.