Electronics and Telecommunications Research Institute

Sk Telecom Company, Ltd.

Ktfreetel Co., Ltd

Kt Corporation

Bong-Ju Lee

Won-Ik Kim

Yeon-Seung Shin

Seung-Kwon Baek

Jae-Su Song

Sung-gu Choi

Soo-Chang Kim

Ji-Soo Park

Yeong-Jin Kim

Hyung-sub Kim

The present invention relates to a vertical handoff method. According to the present invention, a serving network of a mobile station is determined. Herein, the mobile station that can access a first network having relatively wide service coverage and a second network having relatively narrow service coverage in an area where service coverages of heterogeneous networks are overlapped. When accessing the serving network of the first network, it is determined whether a received signal strength received from the second network is greater than a first threshold value. In addition, a first vertical handoff is decided by using a result of prediction of a transition pattern of the received signal strength that is greater than the first threshold value. When the serving network is the second network, it is determined whether the received signal strength received from the second network is less than a second threshold value. By using a result of prediction of a transition pattern of the received signal strength that is less than the second threshold value, a second vertical handoff is decided. Herein, the first threshold value is greater than the second threshold value.

Method of vertical handoff

The present invention relates to a device for providing a quality of service (QoS) of a hand-off between heterogeneous networks, and a method thereof. According to the present invention, the device includes a device for performing a QoS management function for each access system and a device for performing a QoS management function between heterogeneous access systems in a network including a plurality of interlocked access systems. The device for performing the QoS management function for each access system manages a user service session, a local QoS of the access system, and a QoS context of the service session. The device for performing the QoS management function between the heterogeneous access systems negotiates the QoS of the service session and manages the QoS context when the hand-off is performed between the heterogeneous access systems, and performs a QoS mapping operation.

Device for providing hand-off quality of service of inter-access systems and method thereof

In a wireless network discovery method according to an exemplary embodiment of the present invention, a) a propagation environment information message generated by using signal information received from the heterogeneous wireless networks is transmitted to the common core network, b) a wireless network discovery range generated by using the propagation environment information message is received from the common core network, c) it is determined if signal information received from a serving wireless network at a current location corresponds to the wireless network discovery range, and d) when the signal information corresponds to the wireless network discovery range in c), a network within the wireless network discovery range is discovered, when the signal information does not correspond to the wireless network discovery range in c), c) is periodically performed.

Method for discovering wireless network for inter-system handover, multi-mode terminal unit and inter-working service server using the method

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Jeonju, South Korea

Bong-Ju Lee