Resource Allocation and Retransmission Scheme for URLLC in Industrial Wireless Networks with Mixed Traffic

Industrial Wireless Networks (IWNs) are expected to guarantee the Ultra-Reliable Low-Latency Communication (URLLC) in future manufacturing systems. However, due to limited resources and unstable radio environment, it is an inherent challenge to improve transmission reliability while maintaining low latency. This paper considers the uplink URLLC of mixed traffic (deterministic traffic and sporadic traffic) in IWNs with multiple channels. For deterministic traffic, an Automatic On-demand Retransmission scheme based on NACK REpetitions (AOR-NRE) is proposed. For sporadic traffic, a Flexible Repetition Coding-based Contention scheme (FRCC) is proposed. Then, the adaptive decision for mixed traffic on a time slicing based scheme and a frequency slicing based scheme is explored based on reliability analysis of AOR-NRE and FRCC. Finally, the advantages of the proposed retransmission schemes over existing works and the significance of adaptive decision are demonstrated via numerical results.