Dynamic Duplicate Deferral Techniques for Redundant Wi-Fi Networks

Wireless communications suffer from disturbance and interference, which prevent reliable data exchanges and preclude their adoption in the real-time applications found at the lower levels of factory automation systems. This is particularly true for Wi-Fi, for which mechanisms like channel hopping and blacklisting are not available. Several solutions were defined in the past few years, which range from the adoption of general-purpose redundancy protocols over conventional communication equipment to proposals like Wi-Red, which offers link-level redundancy. In this paper, an enhancement is presented for the latter solution, which achieves better performance by deferring transmission of duplicate frames. The net effect is a sort of load balancing between wireless channels, which reduces network traffic and increases reliability further.