Reducing handover delays for seamless multimedia service in IEEE 802.11 networks

In IEEE 802.11 wireless local area network (WLAN) environments, handovers occur when a mobile node (client) moves from the coverage area of one access point (AP) to that of another AP. In particular, a handover in multimedia streaming settings requires a series of tasks to be executed - recognising the disconnection to the currently associated AP, searching for other APs in client visibility and so on. The time taken to perform these tasks gives rise to an interruption of service for about 6 s, which greatly decreases users´ quality of experience (QoE). To reduce service disruptions caused by handovers in IEEE 802.11 networks, a soft proactive handover scheme that exploits the received signal strength indicator (RSSI) and scalable video coding (SVC) is proposed. The proposed scheme predicts the time that a handover process is going to start using the RSSI values and receives the lightweight base layer code of the SVC-encoded video during a certain interval before the predicted handover starts. Experimental results show that the proposed scheme can minimise service interruption times during the 802.11 handover operations, thereby increasing QoE.