Self-optimizing Scanning Parameters for Seamless Handover in IEEE 802.11 WLAN

摘要

Within IEEE 802.11 Wireless Local Area Networks (WLANs), a handover between wireless Access Points (APs) is inevitable for the mobile stations to maintain network connectivity as they move. Handover occurs frequently due to the limited coverage range of APs and the mobility of stations (STAs). High handover latency causes interruption to data flow and degrades the quality of service (QoS) experienced by the mobile stations. Therefore, minimizing handover latency is critical for maintaining seamless communications and improved QoS. In this paper, we build upon recent advances in mobile networks whereby Self-Organizing Network (SON) has been shown to work well in handling mobility. Inspired by SON, we propose an algorithm that combines: (i) scanning timers optimized with Genetic Algorithm (GA) and (ii) self-adapting timers to reduce the handover latency for 802.11 WLANs. We use the IEEE 802.11k standard to retrieve radio parameters from measurement reports and feed these parameters to a GA to find the best fit values to reduce scanning delay. We compare the proposed algorithm performance with IEEE 802.11 standard and our previous work neighbor list mechanism (NLM). Evaluation results demonstrate that our proposed algorithm reduce the handover latency by 78.79% compared with standard 802.11, the packet loss is 3.37% lower than standard 802.11 while the throughput improves up to 3.93%.