Repetition Control Method Using Terminal Mobility for Uplink Grant-Free URLLC

This paper proposes a repetition control method using terminal mobility to alleviate the packet collision for uplink grant-free (GF) ultra-reliable and low-latency communications (URLLC). Because the time diversity benefit within repetitions is basically dependent on a fading correlation, the proposed approach determines the number of necessary repetitions using a fading correlation easily obtained from the terminal speed. Using the proposed repetition control, the number of repetitions can be reduced especially in low fading correlations, alleviating packet collision. The effectiveness of our proposed method is demonstrated in terms of latency by computer simulations.