Browsing by Author "Rao, HCH"

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A mobile service platform using proxy technology
(2006-02-01)
Chen, MF
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Lin, YB
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Rao, HCH
;
Wu, Q
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資訊工程學系
This paper proposes iMobile, a proxy-based platform for developing mobile services for various mobile devices and wireless access technologies. iMobile acts as a message gateway that allows mobile devices to relay messages to each other through various protocols on different access networks. It allows mobile devices to access internet services, corporate databases and to control various network devices. iMobile implements three key abstractions: dev-let, info-let and app-let. An info-let provides abstract view of information space. An app-let implements service or application logic by processing information from various info-lets. A dev-let receives and sends messages through any particular protocols for mobile devices. The let engine supports user and device profiles for personalization and transcoding, and invokes proper app-lets and info-lets to answer requests from a dev-let. The Mobile modular architecture allows developers to write device drivers, information access methods and application logic independently from each other. Copyright (c) 2005 John Wiley & Sons, Ltd.
A push mechanism for GPRS supporting private IP addresses
(2003-01-01)
Lin, YB
;
Lo, YC
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Rao, HCH
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資訊工程學系
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Department of Computer Science
General Packet Radio Service (GPRS) provides packet switched data service for mobile users. However, the existing GPRS specification does not provide the push mechanism and it is difficult to support GPRS services such as call termination (incoming call) for wireless voice over IP (VoIP). Based on short message service, this paper proposes a push mechanism for GPRS supporting private IP addresses. Our approach does not need to modify the existing GPRS structure.
Flexible Resource Allocation scheme for GSM data services
(1998-10-01)
Jeng, JY
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Lin, YB
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Rao, HCH
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資訊工程學系
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Department of Computer Science
In GSM High Speed Circuit Switched Data (HSCSD), the data rate can be increased by using multiple time slots instead of single time slot. Multiple time-slot assignment results in high blocking rate. To accommodate more users, flexible resource allocation strategies have been proposed. Since GSM follows TDMA/FDMA, the channels (time slots) in a base station are segmented by frequency carriers. The base station must allocate the channels which belong to the same frequency carrier to individual requests. This Flexible Resource Allocation scheme for GSM (FRA-GSM) is contrastive to the scheme proposed in our previous studies where a base station may arbitrarily allocate idle channels in the base station to incoming requests. We de fine satisfaction indication SI as the measurement to compare the performance of these schemes. Experiment results indicate that FRA-GSM scheme has good performance when the user mobility is high, or when some cost factors are taken into account.
Flexible Resource Allocation scheme for GSM data services
(1998-10-01)
Jeng, JY
;
Lin, YB
;
Rao, HCH
;
資訊工程學系
;
Department of Computer Science
In GSM High Speed Circuit Switched Data (HSCSD), the data rate can be increased by using multiple time slots instead of single time slot. Multiple time-slot assignment results in high blocking rate. To accommodate more users, flexible resource allocation strategies have been proposed. Since GSM follows TDMA/FDMA, the channels (time slots) in a base station are segmented by frequency carriers. The base station must allocate the channels which belong to the same frequency carrier to individual requests. This Flexible Resource Allocation scheme for GSM (FRA-GSM) is contrastive to the scheme proposed in our previous studies where a base station may arbitrarily allocate idle channels in the base station to incoming requests. We de fine satisfaction indication SI as the measurement to compare the performance of these schemes. Experiment results indicate that FRA-GSM scheme has good performance when the user mobility is high, or when some cost factors are taken into account.
iGSM: VolP service for mobile networks
(2000-04-01)
Rao, HCH
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Lin, YB
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Cho, SL
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資訊工程學系
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Department of Computer Science
This article proposes iGSM: a voice-over-IF value-added service for mobile network. The iGSM service provides user mobility to subscribers, which allows them to use either GSM handsets or H.323 terminals (IP phones or PCs) to access telecommunications services. We describe how the iGSM registration, deregistration, and call delivery procedures can be implemented without modifying the GSM network. We study how the tromboning effect in the standard GSM system can be avoided when accessing the IP network. Then we investigate the misrouting problem caused by user mobility.
Impact of mobility on mobile telecommunications networks
(2005-11-01)
Lin, YB
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Pang, AC
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Rao, HCH
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資訊工程學系
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Department of Computer Science
This paper describes the mobility management mechanisms for mobile telecommunications networks. There are two major types of mobility: radio network mobility and core network mobility. Radio network mobility supports radio link switching of a mobile user during conversation, and core network mobility provides roaming and tunnel-related management for packet re-routing due to user movement. Impact of mobility on both the radio and the core networks is addressed in this paper. Also, potential research issues on these topics are discussed. Copyright (C) 2005 John Wiley & Sons, Ltd.
iSMS: An integration platform for Short Message Service and IP networks
(2001-03-01)
Rao, HCH
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Chang, DF
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Lin, YB
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交大名義發表
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National Chiao Tung University
This article describes iSMS, a platform that integrates IP networks with the Short Message Service in mobile telephone systems. iSMS provides a generic gateway for creating and hosting wireless data services for mobile stations. Our approach does not require any modification to the mobile telephone system architecture. The iSMS system can be quickly developed and operated by a third party or end user without involvement of mobile equipment manufacturers and telecom operators. Based on the iSMS platform, we illustrate services such as e-mail delivery/forwarding, Web access (e.g., stock and train schedule query) and handset music services. The iSMS platform and the services have been implemented for GSM networks With iSMS, users are able to use standard GSM handsets to access wireless Internet services, while other approaches like Wireless Application Protocol and SIM Toolkit services require function-enabled MSs.
Mobile prepaid phone services
(2000-06-01)
Lin, YB
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Chang, MF
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Rao, HCH
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友訊交大聯合研發中心
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D Link NCTU Joint Res Ctr
During the past few years, the mobile prepaid service has been growing exponentially all over the world. Four approaches have been proposed to provide mobile prepaid service. We describe these approaches and compare their strengths and weaknesses. Our analysis indicates that the handset based approach is a low-cost, high-risk solution. The wireless intelligent network approach is a high-cost, low-risk solution. The service node approach is a quick solution, which allows fast deployment with limited capacity. The hot billing approach is an average solution that cannot provide real-time rating.
Number portability for telecommunication networks
(1999-01-01)
Lin, YB
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Rao, HCH
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資訊科學與工程研究所
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Institute of Computer Science and Engineering
Number portability-is a telecommunication network function, which allows subscribers to switch services, service providers, or locations without changing their telephone numbers; Near-term number portability is typically implemented by existing telecommunication services such as remote call forwarding. Long-term number portability can be implemented under the advanced intelligent network platform. In this article we introduce the number portability Issues and provide a tutorial on AIN. Then we show the AlN implementation number portability. Finally, a cache approach is proposed to speed up address transfer, which can effectively reduce the network overhead incurred by AIN query for number portability.
Number portability for telecommunication networks
(1999-01-01)
Lin, YB
;
Rao, HCH
;
資訊科學與工程研究所
;
Institute of Computer Science and Engineering
Number portability-is a telecommunication network function, which allows subscribers to switch services, service providers, or locations without changing their telephone numbers; Near-term number portability is typically implemented by existing telecommunication services such as remote call forwarding. Long-term number portability can be implemented under the advanced intelligent network platform. In this article we introduce the number portability Issues and provide a tutorial on AIN. Then we show the AlN implementation number portability. Finally, a cache approach is proposed to speed up address transfer, which can effectively reduce the network overhead incurred by AIN query for number portability.
Reducing the network cost of call delivery to GSM roamers
(1997-09-01)
Cho, YJ
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Lin, YB
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Rao, HCH
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資訊工程學系
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Department of Computer Science
When a GSM user travels to a foreign country, ii is anticipated that a call delivery From a caller in that country to the GSM roamer should be a local phone call. Unfortunately, under the current GSM implementation, the call delivery results in two international calls! In this article we explain why current GSM implementation is expensive for this kind of call delivery, and then propose four solutions to reduce the two international calls into one local phone call. Our solutions may significantly reduce the nonnecessary usage of international circuits as well as customer costs.
Reducing the network cost of call delivery to GSM roamers
(1997-09-01)
Cho, YJ
;
Lin, YB
;
Rao, HCH
;
資訊工程學系
;
Department of Computer Science
When a GSM user travels to a foreign country, ii is anticipated that a call delivery From a caller in that country to the GSM roamer should be a local phone call. Unfortunately, under the current GSM implementation, the call delivery results in two international calls! In this article we explain why current GSM implementation is expensive for this kind of call delivery, and then propose four solutions to reduce the two international calls into one local phone call. Our solutions may significantly reduce the nonnecessary usage of international circuits as well as customer costs.