Fast and seamless handover for secure mobile industrial applications with 802.11r

Concerning its temporal behavior the latency caused by a handover from one access point (AP) to another is of particular interest for mobile industrial applications, e.g. automated guided vehicles, due to their real-time requirements in the range of a few milliseconds. With the advancements of wireless local area networks, fast roaming support has become one of the most important issues in IEEE 802.11. The IEEE 802.11r standard amendment has been specified to address roaming capabilities of real-time applications with an attempt to minimize BSS transition time while still providing the 802.11i security and 802.11e QoS. 802.11r permits seamless connectivity with a fast and secure handover from one AP to another within the same mobility domain. It provides an opportunity to derive encryption keys prior to a reassociation to reduce the connectivity loss during the handover. It also provides features for resource reservation and central mobility management. This paper presents an implementation of 802.11r based on a Linux operating system. It uses a softMAC approach that allows moving the processing of MAC layer management entity (MLME) from kernelspace to userspace. Measurement results show the performance gain of 802.11r as compared to a legacy implementation in terms of a handover time reduction, which is a core requirement of wireless industrial networks.