Extreme ultra-reliable and low-latency communication

Ultra-reliable and low-latency communication (URLLC) is central to fifth-generation (5G) communication systems, but the fundamentals of URLLC remain elusive. New immersive and high-stake control applications with stricter reliability, latency and scalability requirements are now also creating unprecedented challenges for URLLC. Here we examine the limitations of 5G URLLC and propose key research directions for the next generation of URLLC, which we term extreme ultra-reliable and low-latency communication (xURLLC). xURLLC is underpinned by three concepts: the leveraging of recent advances in machine learning for faster and more reliable data-driven predictions; complementing radiofrequency signal transmission with non-radiofrequency data and passive signal reflection to combat rare events at scale; emphasizing joint communication and control co-design, as opposed to the communication-centric approach of 5G URLLC. For each of these concepts, we consider the challenges and opportunities, and illustrate the effectiveness of the proposed solutions through selected use cases.