Browsing by Author "Tu, Yuan-Kuang"

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DEPLOYMENT OF THE FIRST COMMERCIAL LWA SERVICE
(2017-12-01)
Tu, Yuan-Kuang
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Lee, Cheng-Hua
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Liu, Chia-Horng
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Chia, Chung-Yung
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Chen, Yuan-Kai
This column reports the deployment of the first commercial LWA service. The deployed LWA network reuses and is merged with the existing individual LTE and WLAN networks. Our experience indicates that this approach allows quick establishment of LWA service, which nicely resolves the coexistence problems arising from deploying the LTE system in unlicensed spectrums. Specifically, in the initial stage, selected LWA hotspots with the required service were built in two months. Through this deployment, we show how Chunghwa Telecom utilizes unlicensed spectrum to open up additional capacity to support LTE service. Specifically, the throughput of an LWA site can be more than twice of that for an LTE eNB. Also, through an LWA eNB, an LWA-capable user equipment can indirectly perform seamless handover between a Wi-Fi AP without mobility capability and a standard eNB. This indirect handover time is less than 400 ms plus the standard EAP-SIM authentication time for Wi-Fi.
IMS EMERGENCY SERVICES: A PRELIMINARY STUDY
(2011-02-01)
Lin, Yi-Bing
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Tsai, Meng-Hsun
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Tu, Yuan-Kuang
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資訊學院
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College of Computer Science
Emergency call and walkie-talkie are two services utilized in emergency situations. During Typhoon Morakot in 2009, we experienced the deficiency of emergency call service that cannot continuously track callers in real time and walkie-talkie communications where a speaker may not be granted the permission to talk. These issues can be resolved by the emergency call and push-to-talk over cellular services in IP Multimedia Subsystem. This article conducts a preliminary study on how these two services can be effectively exercised in IMS.