—We discuss the applicability of IEEE 802.15.4 for application in industrial automation. Based on the specific requirements in this field, especially w.r.t. real-time operation, we analyzed the weaknesses of the standard protocol and proposed a novel MAC protocol that keeps the original PHY definition in order to work using available IEEE 802.15.4 chipsets. In earlier work, we analytically derived the worst case latency for using the improved protocol version in typical industrial setups. We now also implemented this protocol version in a simulation environment in order to show the typical behavior in the network taking into account typical channel conditions. We performed extensive simulation experiments that show the limitations of the standard protocol and that demonstrate the capabilities of the new protocol in a selected automation scenario. Our protocol variant is going to become the forthcoming IEEE 802.15.4e standard. Keywords-IEEE 802.15.4, real-time communication, perfor...