Improving IEEE 802.15.4 for Low-latency Energy-e cient Industrial Applications

The IEEE 802.15.4 standard for LR-WPANs is becoming a de-facto standard for Wireless Sensor Networks (WSNs) applications in industrial fields. In this paper, we evaluate the latency performance of the IEEE 802.15.4 protocol based on a typical industrial scenario: a star network with 20 devices that send short messages (1 Byte) to the PAN coordinator. We analyzed the behavior of the GTS mechanism in the standard analytically. The results reveal essential limitations of the standard for low-latency applications in automation environments. According to our findings, we propose an enhanced protocol version that fully supports industry demands on low-latency communication. Our protocol version uses the original physical layer and, thus, can be implemented conveniently using cheap IEEE 802.15.4 hardware. The analytical results prove that we are able to meet the guaranteed low latency of 10 ms as specified by typical automation environments.