Browsing by Author "Gan, CH"

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Credit allocation for UMTS prepaid service
(2006-01-01)
Lin, P
;
Lin, YB
;
Gan, CH
;
Jeng, JY
;
資訊工程學系
Prepaid phone service requires a user to make payment before calling. In 2.5G or the 3G networks, a user may be engaged in multiple voice and/or data prepaid sessions at the same time. For such services, it is important to distribute appropriate amounts of prepaid credit units to simultaneously executed sessions of a user. By considering the universal mobile telecommunication system (UNITS) as an example, this paper studies the prepaid credit allocation for the prepaid sessions. To simulataneously accommodate more prepaid sessions for a user, we propose a credit reclaim mechanism called prepaid credit reclaim (PCR). Analysis and simulation experiments are conducted to investigate the performance of our mechanism. Our study indicates that PCR can significantly improve the-performance of the prepaid mechanism.
Effective VoIP call routing in WLAN and cellular integration
(2005-10-01)
Lin, YB
;
Chen, WE
;
Gan, CH
;
資訊工程學系
;
Department of Computer Science
In cellular-WLAN integration, a dual-mode mobile station (XIS) typically disables the WLAN module for power saving. A major problem is that for an incoming VoIP call (or data session), the MS will not be able to receive this call from the WLAN. It turns out that the call is directed to the cellular network. This letter proposes a simple push solution where an MS can accurately detect a VoIP call from paging signaling of the cellular network. Then the WLAN module of the MS is turned on and the VoIP call is connected to the MS through the relatively inexpensive WLAN.