Enhancing reliability in IEEE 802.11 based real-time networks through transport layer retransmissions

As the number of application areas for wireless technologies grows, the need for providing both predictable and reliable communication over wireless networks becomes apparent. Cooperative embedded systems for industrial automation are one example of systems with these needs. Previously, we developed a framework for reliable real-time communication in a single-hop wireless network with a logical star topology. The framework was placed on top of IEEE 802.15.4 and combines transport layer retransmissions with real-time analysis admission control. IEEE 802.15.4 was selected due to its advantageous energy saving techniques, making it an interesting choice for wireless sensor networks in industrial contexts. However, its achievable data rate is rather low, especially when voice or video for industrial surveillance and monitoring need to be transferred. Hence, we adapt our framework to fit the IEEE 802.11 standard and evaluate its performance using a data traffic model from industrial control and surveillance systems. The performance of the framework is evaluated in terms of network utilization, message error rate and delay distribution using theoretical analysis as well as computer simulations.