URLLC Mode Optimal Resource Allocation to Support HARQ in 5G Wireless Networks

Ultra Reliable Low Latency Communication (URLLC) mode is a promising 5G technology for various real-time applications, such as, autonomous vehicles, augmented reality, and factory automation. Several papers on URLLC exist, however, most papers only focus on ways to achieve high reliability, and lack mathematical analysis of delay related to packet errors, retransmissions, and bandwidth. In this paper, a M/G/1 queuing model is applied to analyze the erroneous transmission recovery delay of URLLC multi-user services, and using this model the minimum required bandwidth is derived and applied into an adaptive control scheme. The proposed Pollaczek-Khinchine (P-K) formula based quadratic optimization (PFQO) scheme optimizes the bandwidth requirement by controlling the maximum retransmission parameter of the hybrid automatic repeated request (HARQ) mechanism in URLLC. Simulation results show the bandwidth saving effect of the proposed PFQO scheme based on various signal to interference plus noise ratios (SINRs) and packet length distributions.