Analysis And Design Of Ap’s Quick Roaming

With the rapid development of wireless local area network (WLAN) technology, the demands of wireless users also become diversified. The most widely used currently WLAN technology is WI-FI (Wireless Fidelity) technology. If you want to use WI-FI, firstly you need to buy an AP (Access Point) and a client with a wireless card. Generally speaking, WI-FI’s coverage can reach about90m, which can meet the demand for wireless Internet access for most small businesses and some public places.However, in the actual usage, WI-FI technology also has various restrictions, if the company can take these problems into account in advance, and develop new products to lift these restrictions, this company will be able to expand the existing market share, so that enterprises and users can reach the win-win situation. In some special occasions, such as bus or subway places, users can’t use the WI-FI service, because the user is in the fast moving process, AP can’t provide normal wireless service in that situation. How to provide quality and reliable wireless service to the user in the roaming scenario is this paper focuses on.The application of WI-FI technology in transport is very necessary, because people generally have the habit of using the phone on the bus or subway to kill time. If WI-FI service can be supply on the train, the diversified needs of users will be satisfied, and then the estimate of train’s service will be improved. At the same time, on the places such as golf, the customers sitting in the casual car also need the convenient WI-FI service; such businesses also hope the AP equipment manufacturers can solve the WI-FI’s roaming problems.The characteristics of the user can also enjoy the wireless service in the fast-moving process called "fast roaming". To optimize the design of software is the feature request, and there will be additional hardware overhead in actual configuration, that installs a Fat AP on the vehicle. Fat AP is used as a relay device, which connects the client with the Fit AP in the surrounding, so that the passengers can be associated to the Fit AP, then link to the network. When the vehicle migrate from some Fit AP’s coverage to other, the Fat AP within the vehicles can make the real-time scanning on each channel, then analyses the strength of the signal and select the best Fit AP to associate dynamically. So that it can ensure the continuity of roaming services in the fast-moving environment.Corresponds to different scenarios, roaming function is divided into fast roaming and slow roaming. On the place of bus or subway, vehicle is in fast moving, so it’s suitable to configure fast roaming to Fat AP; on the place of golf the leisure car is in slow moving, it’s suitable to configure slow roaming to Fat AP. Both functions have slightly different in realization, but there are members of fast roaming.There may be set up many APs all over our city in the future, maybe we can enjoy the convenience that brought from the WI-FI service at anytime and anywhere, then, the prospective study this paper have made, will provide some reference to the goal which may come true in the future, and the value of this paper is self-evident.