IEEE 802.11 Link-Layer Handoff Optimization Scheme

Abstract

A growing number of IEEE 802.11-based wireless LANs have been set up in many public places in the recent years. These wireless LANs provide convenient network connectivity to users. Although mobile nodes allowed roaming across wireless LANs, handoff latency becomes an obstacle when mobile nodes migrate between different IP networks. Advanced, the link-layer handoff process disrupts the association when a mobile node moves from one access point to another. Without discussing the latency of Mobility Protocols, this link-layer handoff latency already made many real time applications can not meet their requirements. Several actual network experiments are made to proof this point. In this paper, it is proposed that a link-layer optimization scheme is designed to reduce the latency of link-layer handoff procedure. No violation to the existing specifications in the IEEE 802.11 standard and compatible with existing devices. Since the proposed optimization scheme is worked in the base of whole handoff procedure, whatever which Mobility Protocol is used in the upper-layer, it can take the benefit from the proposed scheme. Several simulations illustrate the proposed scheme can reduce the link-layer handoff duration to 24% compared with the IEEE 802.11 standard and achieve power consumption by decreasing the amount of sending messages in the high traffic load environment. Even real time applications can work under an acceptable situation.