Achieving URLLC by MU-MIMO With Imperfect CSI: Under κ-μ Shadowed Fading

To achieve ultra-reliable and low latency communications (URLLC) in various fading channels is a major challenge. Classical fading models can be unified with a universal fading model, namely, κ-μ shadowed fading. We consider multi-user multiple-input multiple-output (MU-MIMO) and maximal ratio combining detection to achieve URLLC under κ-μ shadowed fading in the uplink. Under imperfect channel state information (CSI), we derive the probability density function of the post-processing signal-to-noise ratio in the κ-μ shadowed fading channel. The finite blocklength information theory is used to calculate the error probability. Simulation results show that under severe κ-μ shadowed fading and imperfect CSI, system parameters can be configured and adapted to the fading parameters to achieve URLLC. The conclusions drawn on the κ-μ shadowed fading model can be applied to almost all classical fading models. In general, we overcome the mathematical intractability of the κ-μ shadow fading model under imperfect CSI, substantially expanding the scope of its application to URLLC.