The three primary colors of mobile systems

In this article, we present the notion of "mobile 3C systems" in which communications, computing, and caching (i.e., 3C) make up the three primary resources/functionalities, akin to the three primary colors, of a mobile system. We argue that in future mobile networks, the roles of computing and caching are as intrinsic and essential as communications, and only the collective usage of these three primary resources can support the sustainable growth of mobile systems. By defining the 3C resources in their canonical forms, we reveal the important fact that caching affects the mobile system performance by introducing non-causality into the system, whereas computing achieves capacity gains by performing logical operations across mobile system entities. Many existing capacity-enhancing techniques such as coded multicast, collaborative transmissions, and proactive content pushing can be cast in the native 3C framework for analytical tractability. We further illustrate the mobile 3C concepts with practical examples, including a system on broadcast-unicast convergence for massive media content delivery. The mobile 3C design paradigm opens up new possibilities as well as key research problems bearing academic and practical significance.