Performance of Real-TimeWireless Communication for Railway Environments with IEEE 802.11p

IEEE 802.11p complements the widespread 802.11 standard for use in vehicular environments. Designed for communication between wireless devices in rapidly changing environments, it handles situations where connection and communication must be completed in very short periods of time. Even though this is supposed to be a substantial improvement and essential for real-time applications, latencies have been rarely investigated in existing studies. Based on practical experiments, we evaluate how beneficial 802.11p’s changes in comparison to regular 802.11n are and whether the usage of IEEE 802.11p is suitable within environments with real-time constraints. We compare latencies of networks in OCB mode to both networks in IBSS (ad-hoc) and BSS/AP (access point) mode by measuring the initial connection speed and the latency of ICMP packets’ round-trip times. Furthermore, the response of the latter to disturbances is measured. The results show OCB to be superior to both BSS/AP and IBSS modes in average latency, maximum latency, and standard deviation under all tested circumstances