Outage Prediction for URLLC in Rayleigh Fading

A major challenge for the realization of ultra reliable low latency communications (URLLC) systems is the fast fading of wireless channels and the therewith associated outages. To overcome the fading, diversity concepts, as well as transmissions with low modulation order and low code rate are widely considered. However, these methods have an undeniably high resource consumption. In order to reduce it, fading prediction methods can be utilized as part of the scheduling strategy. We propose a novel outage prediction approach based on a Wiener filter that significantly helps to increase URLLC system monitoring and radio resource scheduling. In this paper we focus on Rayleigh fading channels and classical Doppler spectra. The proposed outage predictor is found to work on a wide range of sampling times and also with only a few observed fading samples available. During operation, future outage probabilities can be calculated beforehand and reliability guarantees can be made. Utilizing the proposed outage prediction method increases the achievable reliability of a link by several orders of magnitude compared to best effort transmissions on a single link. Links that are operable are well identified when little movement is present and prediction of several milliseconds is sufficient.