Resource Optimization for Noncoherent Short-Packet Communications with IR-HARQ

1This paper investigates the noncoherent communications employing finite blocklength (FBL) channel codes over a single-antenna, Rayleigh block-fading channel under quality-of-service (QoS) constraints. The incremental redundancy hybrid automatic repeat request (IR-HARQ) with one additional retransmission round is incorporated to enhance the reliability. Effective capacity is employed to characterize the throughput with renewal service processes under statistical delay constraints. A framework for minimizing the total transmission power to ensure ultra-reliable and low-latency communications (URLLC) under minimum throughput constraint is established. An efficient algorithm is proposed to derive the optimal power allocation policy. Through numerical evaluations, it is demonstrated that the proposed transmission policy can achieve better performance than the single-shot transmissions.