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Optimizing the Performance of Handoff Management in Wireless LANs


Li Jun Zhang, Samuel Pierre


Vol. 8  No. 7  pp. 87-94


As the radio range of access point (AP) in a wireless local area network (WLAN) is about 35 meters, mobile nodes (MNs) have to frequently undergo a handoff process when they move beyond the radio coverage area of their associated APs. However, legacy IEEE 802.11-based standards cannot provide sufficient support for mobility management. Besides, as the demands from wireless users for real-time multimedia services increase, quality of service provisioning becomes a challenging issue for mobile users in WLANs. Under the circumstances, this paper proposes a new handoff management scheme to support ongoing real-time applications while MNs change their network attachment points. This MAC-layer-based approach consists of minimizing the total number of scanned channels during handoff, and reducing the probe-waiting time for each examined channel. To analyze the efficiency of the proposal, simulations are conducted with the simulator SimulX for MNs roaming in an environment that integrates the standard mobile IPv6 (MIPv6) with IEEE 802.11b. Simulation results show that our proposed solution delivers better performance than the IEEE 802.11b standard, a variation of this standard in which an MN waits for MinChannelTime on each probed channel, and two other well-documented approaches in the literature: Selective scanning plus AP Caching (Selective + Caching) and Neighbor Graphs.


Mobility management, Handoff management, Scanning, Wireless LAN.