New Approaches Reducing Handoff Latency in 802.11 Wireless LANs

摘要

Wireless local area networks (WLAN) have seen rapid growth and deployment in the recent years. It has become the state-of-the art campus networking option in many academic and corporate campuses. As Wi-Fi technology becomes ubiquitous, it is important to understand trends in the usage of these networks. As the mobile clients are moving from one access point to another, the convectional layer-2 handoff consumes more time in the channel-scanning process. The proposed handoff mechanism for mobility management is designed to minimize the handoff latency in IEEE 802.11 wireless local area network. It reduces the discovery phase according to two models extended from the basis model. There are two methods to implement Handoff functions in the MAC layer. The first method is CPU-based solution. It uses software for protocol analysis and CPU, such as DSP, for process management. It is more flexible in design stage and easy to modify, however the low processing speed and the higher cost present its major weakness. The second method means that all functions are processed by hardware circuits. The advantage of this method is circuit reconfiguration and processing speed very high, but it needs long developed time. We propose the last method to implement handoff functions in the MAC layer.