5G URLLC: Design Challenges and System Concepts

The upcoming fifth generation (5G) wireless communication system is expected to support a broad range of newly emerging applications on top of the regular cellular mobile broadband services. One of the key usage scenarios in the scope of 5G is ultra-reliable and low-latency communications (URLLC). Among the active researchers from both academy and industry, one common view is that URLLC will play an essential role in providing connectivity for the new services and applications from vertical domains, such as factory automation, autonomous driving and so on. The most important key performance indicators (KPIs) related to URLLC are latency, reliability and availability. In this paper, after brief discussion on the design challenges related to URLLC use cases, we present an overview of the available technology components from 3GPP Rel-15 and potential ones from Rel-16. In addition, coordinated multi-cell resource allocation methods are studied. From the system level simulation results in an urban macro environment, it can be observed that effective multi-cell cooperation, more specifically soft combining, can lead to a significant gain in terms of URLLC capacity.