1. Field of the Invention
The present invention relates to a wireless LAN (Local Area Network) terminal, a wireless LAN base station connected thereto, a wireless communication method performed on the wireless LAN terminal, a wireless communication method performed on the wireless LAN base station, and a roaming method performed on the wireless LAN terminal.
2. Description of the Related Art
In recent years, there is a spreading use of wireless LAN terminals and wireless LAN base stations to perform wireless communication in compliance with standards such as IEEE (Institute of Electrical and Electronics Engineers) 802.11a, IEEE 802.11b, and the like. The wireless LAN terminal is mounted on a personal computer, a personal digital assistant, and the like. This makes it possible to allow the personal computer and the personal digital assistant to communicate with each other via the wireless LAN base station. When the wireless LAN base station has also a router and an ADSL (Asymmetric Digital Subscriber Line) modem, the personal computer and the personal digital assistant can access the Internet via the wireless LAN base station.
A prior art related to the present invention provides connection between a group of machines and a group of personal computers using a PHS (e.g., see patent document 1).
Another prior art related to the present invention allows communication between a first wireless data communication apparatus and a second wireless data communication apparatus via another wireless data communication apparatus (e.g., see patent document 2).
[Patent document 1] Japanese Patent Application Laid-Open Publication No. 1999-74899
[Patent document 2] Japanese Patent Application Laid-Open Publication No. 1996-97821
However, there is a limit on a distance capable of communication between the wireless LAN terminal and the wireless LAN base station. Conventionally, in order to eliminate such limit and expand a wireless LAN area, it has been necessary to install a plurality of wireless LAN base stations, make cable connection between the wireless LAN base stations, and install wireless LAN repeaters, for example. Disadvantages of additional installation costs, spaces, and labors result from such requirements as installing a plurality of wireless LAN base stations, making cable connection between the wireless LAN base stations, and installing wireless LAN repeaters.
The prior art of patent document 1 just connects a conventional PHS to a group of machines and a group of personal computers. According to the prior art of patent document 2, the first wireless data communication apparatus must check paths to the second wireless data communication apparatus before communicating with the second wireless data communication apparatus.