Comparative End-to-End Delay Analysis of Repetition and RaptorQ Codes for URLLC in Smart Factory Automation

Ultra Reliable Low Latency Communication (URLLC) is crucial for industrial factory automation, where stringent delay and reliability requirements must be met. Hence, this paper evaluates the end-to-end delay (E2E) performance of two Forward Error Correction (FEC) techniques such as Repetition codes and RaptorQ codes within a large-scale factory environment. To assess their reliability under challenging conditions, 100 sensors per square kilometer are deployed, and performance is analyzed across two frequency spectrums: 3.5GHz (mid-band) and 28GHz (high band). The results demonstrate that RaptorQ codes consistently meet the strict URLLC latency requirement of 1ms, outperforming Repetition codes in all scenarios. The results indicate that RaptorQ at 3.5GHz achieved a maximum coverage of 420 meters for end-to-end (E2E) delay under perfect CSI, 380 meters with frequency diversity, and 360 meters under imperfect CSI without frequency diversity. The study further highlights the benefits of RaptorQ's systematic encoding in maintaining low-latency communication, especially in dynamic industrial environments.