Safety Layer Techniques in Wireless Links under Severe Fading

This paper presents a method to evaluate the feasibility of using wireless links as part of functional safety systems. We present an analytical model to describe the wireless safety links' performance operating in fading industrial environments. The work considers integrity failures, wrong addressing, message sequence errors, and masquerade events. The contributions of each perturbation to the overall system residual error are modeled with equations. Moreover, a MAC scheme based on the tools suggested in IEC 61784–3 is proposed and validated under industry-recommended use case parameters. The results show that the variation of the frame structure and application-specific parameters impact the overall residual error. The work concludes that the residual error probability of the CRC dominates residual error performance, but it may be reduced using consistent countermeasures against other possible sources of error.