Investigation of 5G NR physical layer enablers for URLLC: a simulation study

Abstract

Ultra reliable low latency communication (URLLC) is a use case of 5G which requires high reliability and low latency. We need to evaluate the capability of various physical layer technologies in achieving such high quality of services (QoS) in realistic channels, so as to devise novel technologies which can bridge the gaps identified. In this paper, we are using VIENNA 5G simulator to achieve 5G URLLC, by combining system and link level simulations, using the third generation partnership project (3GPP) specifications for 5G. Extensive simulation data is analyzed to evaluate the QoS and radio resource efficiency of various physical layer techniques to achieve 5G URLLC. We calculate the threshold signal to noise ratio (SNR) in additive white Gaussian channel (AWGN) which can be used for link adaptation in URLLC when using short packets. Closed loop link adaptation and macro-diversity are found to be more effective methods to achieve high reliability as compared to open loop micro-diversity. Relaxed error target per macro-diversity link is shown to provide better radio resource efficiency as compared to using same error target for all links. It is also shown that flexible subcarrier spacing and mini-slot level scheduling can support required transmission delay so as to meet the target end-to-end latency.