Predictive handoff mechanism with real-time mobility tracking in a campus wide wireless network considering ITS

Allowing users to discover and communicate their positions in the physical world has long been identified as a key component in emerging mobile computing applications. Pervasive positioning is required for the wide scale adaptation of location awareness. Vehicular communication in a campus wide hotspot plays a major role in establishing this. To provide seamless roaming between a subnet in a hotspot and to track the position of the mobile client is the main objective of this paper. wireless local area networks (WLANs) have 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 base station/access point to another, the conventional layer-2 handoff consumes more time in the channel-scanning process. It takes around 310 ms, which leads to a heavy packet loss in real-time applications. The proposed dynamic handoff mechanism for mobility management is designed to minimize the handoff latency in IEEE 802.11 wireless local area networks, which in turn reduces the data loss and the signalling overhead in real-time applications. In this mechanism, threshold points are considered to provide better solution for fast and ping-pong type moving clients in a campus wide network. In our approach the base station (BS) range is divided into two zones namely Z1 - Good and Z2 - Average zone based on the signal strength as well as the distance. To predict the location of the mobile client in a campus wide network, a location prediction is introduced. Based on the location of the mobile client, signal strength and capacity of the BS, the minimal required resources are proactively reserved for the mobile client. A pre hand-off initiation algorithm is triggered when the mobile unit (MU) enters the minimum threshold (Th_min) point. The threshold points are used to provide the handoff region (signal) notification to the mobile user. The MU receives the information about the candidate BS with QoS parameters. The dynamic channel scanning is incorporated in all the access routers and the switching centre (backbone router) to provide various QoS parameters to enhance the layer-2 handoff process and thus to reduce the layer-2 handoff latency. The experimental results are compared with the conventional layer-2 handoff latency for a campus wide network. The latency time is reduced from 310 to 33 ms, which is more suitable for real-time applications in a campus wide network.