The Influence of CSI in Ultra-Reliable Low-Latency Communications with IR-HARQ

Emerging 5G networks will need to efficiently support ultra-reliable, low-latency communication (URLLC), which requires extremely low latency (at msec order) with very high reliability (99.999%). In this work, we consider a URLLC system with incremental redundancy hybrid automatic repeat request (IR-HARQ) and investigate the effect of channel state information (CSI) at the transmitter on throughput and energy consumption optimization. For that, we analyze the feasibility region and the performance in block fading channels for the cases of full and statistical CSI. Our results show that in our setup the full CSI scheme is less robust and we also reveal a desirable balance between the trade-off quantities of energy and throughput.