Latency Components and Analysis in 5G New Radio

Low latency communications are a crucial enabling factor of several 5G New Radio (NR) use cases. In fact, the support of ultra-reliable low-latency communications (URLLC) in 5G NR opens doors to a panoply of wireless applications such as robotics, autonomous driving, telesurgery, virtual reality and telepresence. To achieve URLLC, the long-term evolution of network architecture and key enabling communication technologies are necessary. Since its initial conception, the design of 5G NR has been made with the objective of drastically minimizing the latency at various segments (such as the air interface, fronthaul, backhaul, edge, core and transport) in its end-to-end network. In this paper, a detailed analysis of the concept of latency in the 5G NR communication system in terms of the end-to-end network, user plane and control plane latency is presented. Moreover, the different enabling technologies to achieve URLLC are also reviewed. Challenges that remain to be addressed and gaps in current research are also identified.