Patent ID: 7127234

Claim:
A wireless LAN access authentication system in a network system comprising a plurality of wireless LAN network systems and a center station that controls said plurality of wireless LAN network systems in a centralized manner, each of said plurality of wireless LAN network systems comprising at least two access point sections accessed by a radio terminal apparatus that transmits/receives a radio signal through a radio section and a gateway apparatus which relays transmission/reception of data signals and control signals between said access point sections, said center station comprising a center station gateway apparatus that relays transmission/reception of data signals and control signals between the gateway apparatuses of said plurality of wireless LAN network systems and an authentication server that performs access authentication on said radio terminal apparatus which has accessed said access point sections and distributes cryptographic keys used for encryption of a radio section through which said access-authenticated radio terminal apparatus carries out communication to said radio terminal apparatus and said access point section, said wireless LAN access authentication system comprising: an access control section provided for each of said plurality of wireless LAN network systems for controlling the situation of access of said radio terminal apparatus in the own communication area to said authentication server and checking the presence/absence of access of said radio terminal apparatus to said authentication server when said radio terminal apparatus moves to a communication area of a new access point section; and a cryptographic key control section provided for each of said plurality of wireless LAN network systems for controlling cryptographic keys distributed from said authentication server and distributing, when said access control section confirms that said radio terminal apparatus which has moved to the communication area of the other access point section has already accessed said authentication server, the cryptographic key for said radio section through which said radio terminal apparatus carries out communication to said radio terminal apparatus and said new access point section in the area to which said radio terminal apparatus has moved.