Sk Telecom Company, Ltd.

Electronics and Telecommunications Research Institute

Yong-Sik Shin

Dong-Hahk Lee

Soon-Ik Jeon

Soon-Young Eom

Young-Bae Jung

Jae-Ick Choi

Seong-Soo Park

Sang Shin Lee

Chan-Jeom Phang

Si-Hoon Ryu

An antenna system includes: an orthogonal multi-polarization antenna configured to output independent double orthogonal polarizations through two independent input/output terminals; an antenna main control unit configured to perform a polarization control algorithm, collect and analyze information for polarization control, and provide polarization control information; and a polarization control unit configured to perform independent amplitude and phase control with regard to a pair of independent channels connected to the orthogonal multi-polarization antenna, based on the polarization control information received from the antenna main control unit, so that various polarizations are formed.

Antenna system having adaptive polarization control

The present invention relates to a roaming method between a WLAN and a cellular network which can interwork the WLAN and the cellular network on the basis of a mobile IP system for smooth roaming. In data communication in the WLAN and/or the cellular network using the mobile IP system, the roaming method between the WLAN and the cellular network includes a step wherein a packet data serving node of the cellular network which recognizes allocation of an IP address to a specific mobile terminal notifies information on a current access state of the mobile terminal to an access point managing means of the WLAN located in a current service area of the mobile terminal, a step wherein the access point managing means which the mobile terminal newly accesses requests address renewal to replace an address of the packet data serving node by its address, allocates an IP address to the mobile terminal according to the renewal result, and notifies it to the packet data serving node, and a step wherein the packet data serving node which receives the notification message from the access point managing means transmits data obtained during the roaming due to the movement to the access point managing node, whereby the roaming is performed from the cellular network to the WLAN. In the same manner, the roaming can be performed from the WLAN to the cellular network.

Roaming method between wireless local area network and cellular network

The present invention discloses an apparatus and method for deciding an access system based on WLAN signal strength in a WLAN/mobile phone network interworking system, and a mobile terminal therefor. The method for deciding the access system based on the WLAN signal strength in the WLAN/mobile phone network interworking system includes an initialization step for performing an initialization process on a WLAN driver module and a mobile phone network driver module, and measuring and displaying WLAN signal strength, a service decision step for selecting a WLAN service or mobile phone network service according to the measured WLAN signal strength, and a service access step for enabling the corresponding driver module to access the service decided in the service decision step. The apparatus and method for deciding the access system based on the WLAN signal strength provide a roaming service by efficiently interworking a WLAN which provides a high speed internet access service based on hot spots and a mobile phone network which provides a national communication service, to facilitate activation of the wireless internet service.

Apparatus and method for deciding access system based on WLAN signal strength in WLAN/mobile network interworking system, and mobile terminal therefor

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Seoul, South Korea

Yong-Sik Shin