Optimized transmission and resource allocation strategies for ultra-reliable communications

Fifth generation (5G) wireless systems will provide connectivity for a wide range of new applications with diverse requirements. In part, the network needs to support ultra-reliable communications with low-latency (URLLC) for mission-critical applications. For these applications, the generated data should be delivered with a limited number of transmission attempts with high success probability. This paper considers the optimal transmission and resource allocations for URLLC in cellular systems. The resource allocations are derived for the fixed and adaptive transmission attempt assignments. The analysis results reveal that both fixed and adaptive transmission assignments, applicable to automatic repeat request (ARQ) and hybrid ARQ (HARQ) schemes, can reduce the required resources compared to the equal transmission assignment.