Survey of enablers to overcome latency in 5G and beyond radio access networks.

Abstract

One of the most important 5G requirements is to minimize latency as low as 1ms within the network for new delay-sensitive applications, such as traffic efficiency and safety, and remote control of machinery besides satisfying higher date rate and high number of connected devices. This paper reviews major contributors include Hybrid Automatic Repeat Request (HARQ) retransmissions, current Transmission Time Interval (TTI) length, coding and legacy scheduling mechanisms for low latency purpose. To address latency challenge, each contributor has to be independently considered and can be either minimized or eliminated by defining some important latency sources for air interface. In addition, it suggests some technical enablers or existing recent algorithms towards overcoming latency issue. We also discuss some key challenges and future works in supporting the latency requirements for next generation networks.