  With the fast evolving of cloud computing and artificial intelligence (AI),
the concept of digital twin (DT) has recently been proposed and finds broad
applications in industrial Internet, IoT, smart city, etc. The DT builds a
mirror integrated multi-physics of the physical system in the digital space. By
doing so, the DT can utilize the rich computing power and AI at the cloud to
operate on the mirror physical system, and accordingly provides feedbacks to
help the real-world physical system in their practical task completion. The
existing literature mainly considers DT as a simulation/emulation approach,
whereas the communication framework for DT has not been clearly defined and
discussed. In this article, we describe the basic DT communication models and
present the open research issues. By combining wireless communications,
artificial intelligence (AI) and cloud computing, we show that the DT
communication provides a novel framework for futuristic mobile agent systems.
