TTWiFi: time-triggered communication over WiFi

Abstract

WiFi is prevalent in mobile robotics and the Internet of Things (IoT) despite the fact that many applications in these environments require real-time communication. WiFi does not guarantee timeliness and often introduces unbounded communication delays. We present TTWiFi, a time-triggered protocol for fault-tolerant real-time communication between devices situated in a broadcast domain, that only requires minor changes to IEEE 802.11 parameters and remains standards-compliant in critical aspects. We implemented TTWiFi on a representative platform and benchmarked our implementation with TCP and UDP over unmodified WiFi. Our results demonstrate that unlike the latter, TTWiFi has the ability to maintain communication in a congested environment while exhibiting fail-silent behaviour crucial for fault tolerance and real-time communication.