Low On Air: Inherent Wireless Channel Capacity Limitations

Wireless connectivity has fundamentally changed the way we connect and interact with the world. Over the past fifteen years there has been an exponential increase in wireless data usage, a trend that is predicted to continue. The overall capacity for wireless connectivity is limited in that it operates over electromagnetic spectrum, and the usable range of spectrum is both finite and already scarce. We argue that the growth in demand that we currently see is unsustainable in the long-term, as spectrum resources will become fully exhausted. While current lines of research seek to increase spectrum efficiency, increases in the future will achieve diminishing returns. In this work we present current technologies as well as cutting-edge research related to maximizing the efficiency of wireless systems, and offer research questions that will become critical as we near the limits of wireless connectivity.