Description

WiFi-based networks are becoming increasingly ubiquitous, and in many cases entire cities and campuses are being covered. Though it may be possible to get brief periods of connectivity these networks and the WiFi technology itself are not designed to provide connectivity to moving vehicles. Using measurements from VanLAN, a modest-size testbed that we have deployed, we analyze the fundamental characteristics of WiFi-based connectivity between base stations and vehicles in urban settings. Our results uncover a more complex picture than previous work which was conducted in more benign settings. The impressive penetration of 802.11-based wireless networks in many metropolitan areas around the world offers, for the first time, the opportunity of a “grassroots” wireless Internet service provided by users who “open up” their 802.11 (Wi-Fi) access points in a controlled manner to mobile clients. In Wi-Fi based vehicular environments, there is lot of interrupts in the Access Points (APs). To avoid this new scheme called SWIMMING is proposed. The client broadcast the packet request to APs and an ACK detection scheme is included for collision detection. The packet reaches the client through multiple APs which dynamically follow the moving client.