Prioritized resource reservation for reducing random access delay in 5G URLLC

This paper proposes a resource reservation scheme to reduce random access delay for Ultra-Reliable and Low-Latency Communication (URLLC) traffic. URLLC has been proposed as one of the key usage scenarios in the fifth generation (5G) of mobile networks. The primary requirement for providing URLLC services is the delay in the control plane being shorter than 10 ms. Clearly, it is challenging to achieve such the stringent delay requirement since the bursty URLLC requests can cause network congestion in the random access phase. To reduce the random access delay, we propose to reserve random access resources for URLLC during the initial random access transmission. The design criteria of random access and an analytical model for different reservation policies are presented in this paper. Simulation results show that the existing random access scheme fails to meet the delay requirement for URLLC traffic, but our proposed reservation scheme can meet the 10 ms delay requirement with 95% confidence.