DROO: Integrated Learning and Optimization for Edge Computing Offloading

URLLC is a new service category in 5G to accommodate emerging services and applications having stringent latency and reliability requirements. In order to support URLLC, there should be both evolutionary and revolutionary changes in the air interface named 5G NR. In this article, we provide an up-to-date overview of URLLC with an emphasis on the physical layer challenges and solutions in 5G NR downlink. We highlight key requirements of URLLC and then elaborate the physical layer issues and enabling technologies including packet and frame structure, scheduling schemes, and reliability improvement techniques, which have been discussed in the 3GPP Release 15 standardization. 1. What is the major contribution of this paper? This paper provides a top-down overview of URLLC in 5G in an accessible way, helping researchers and practitioners to understand newly introduced use case in 5G. Key distinctive feature of the paper is, other than the basic introduction on URLLC, elucidation of physical layer solutions to reduce the physical layer latency, such as packet and frame structures, scheduling schemes (instant and reservation-based scheduling), and coexistence handling techniques (reactive and proactive strategies). 2. Are there any new researches or results relevant to this paper? How do you see the development of this research in the near future? URLLC will serve a key use case for machine-centric communication era in 6G. There are numerous future applications related to URLLC, such as driverless car, drone taxi, remote robot-based surgery, virtual reality, and various smart stuffs (smart factory, smart city, smart traffic system). For example, autonomous driving fortified by URLLC technology will eliminate human error and mistakes, reducing the accident and traffic jam on the road. It will also make fully automated transportation possible, reducing the delivery cost significantly while improving the reliability and safety. To realize this goal, cooperation and interplay among all parts of communication layers, from physical layer all the way to the application layer, is of great importance. At the time of this writing (spring of 2017), we did not have a clear picture on this new direction but we now have far better understanding and how URLLC will shape future society. In fact, in line with the dissemination of 5G networks, we are witnessing bewildering variety of research works, real design and test, and demonstration of URLLC applications.