Ktfreetel Co., Ltd

Korea Telecom Freetel Co., Ltd.

Byung-Ik Ahn

Chan-Ho Yun

Cheol-Hyun Kang

Seong-Jin Choi

Yuon-Pil Jeung

Ki-Hong Kim

Kwang-Wouk Lee

Kwang-Wuk Lee

The present invention relates to a method for increasing standby time of mobile terminal and device thereof, and more particularly in a mobile terminal that performs voice and/or data communication by switching between at least two networks using different protocols, and method for increasing standby time using an access history and the device thereof. According to the present invention, the minimized hybrid operation can increase the standby time of the mobile terminal. Also, by minimizing hybrid operation of a plurality of IS-856 mobile terminals, the resource efficiency of the EV-DO network can be maximized.

Method for increasing standby time using access history to 1x ev-do network with access terminal and device thereof

Disclosed is a CDMA terminal for providing a CDMA service to a global system for mobile communications (GSM) service subscriber in a CDMA service area which comprises: a subscriber identity module (SIM) cardholder for installing or uninstalling a SIM card of a GSM service subscriber, wherein when a SIM card of the GSM service subscriber is installed in the SIM cardholder in the CDMA service area, specific data are transmitted using a CDMA message in the case of authenticating the GSM service subscriber using information on the GSM service subscriber stored in the SIM card, and when the authentication of the GSM service subscriber is normally completed, the CDMA terminal is used for the GSM service subscriber as a roaming service terminal in the CDMA service area. According to the present invention, the GSM service subscriber can use his SIM card and number in the CDMA service area.

CDMA terminal for providing roaming service to GSM service subscriber in CDMA service area

Disclosed is a roaming service system in a CDMA service area for GSM service subscribers, which comprises a CDMA system comprising a CDMA HLR storing information on subscribers' locations and services, a CDMA MSC connected to the CDMA HLR and accessing calls, and a CDMA terminal wirelessly connected to the CDMA MSC and capable of having a SIM card removably installed therein; a GSM system comprising a GSM HLR storing information on the subscribers' locations and services, a GSM MSC connected to the GSM HLR and accessing calls, an authentication center (AuC) connected to a GSM network and authenticating terminals, and a GSM terminal wirelessly connected to the GSM MSC; and an IRGS connected between the CDMA system and the GSM system and converting signals to execute signal communications between the systems, and when a subscriber of a service provided by the GSM system moves to an area in which the subscriber can use the service provided by the CDMA system and installs the subscriber's SIM card in the CDMA terminal, transmissions of predetermined data necessary for a GSM authentication by the CDMA system being executed using a CDMA message so that tasks of initial location registration of the GSM service subscriber, a location registration when the location is modified, sending and receiving calls with other subscribers, and a short message service (SMS) are enabled.

Roaming service system for GSM service subscriber in CDMA service area, and method for registering locations and transmitting and receiving signals and short messages using the system

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Seoul, South Korea

Byung-Ik Ahn