Showing papers by "Yi-Bing Lin published in 2009"
TL;DR: An analytic model and simulation experiments are proposed to investigate the performance of delayed update and indicate that delayed update can effectively reduce the notification traffic without significantly degrading the valid access probability.
Abstract: IP multimedia core network subsystem (IMS) provides presence service for universal mobile telecommunications system (UMTS). In IMS, the presence server is responsible for notifying an authorized watcher of the updated presence information. If the updates occur more frequently than the accesses of the watcher, the presence server will generate many notifications. This paper uses a weakly consistent scheme (called delayed update) to reduce the notification traffic. In this scheme, a delayed timer is defined to control the notification rate. We propose an analytic model and simulation experiments to investigate the performance of delayed update. The study indicates that delayed update can effectively reduce the notification traffic without significantly degrading the valid access probability.
27 citations
TL;DR: This study indicates that the key caching scheme can effectively speed up the handoff process and eliminate the nonnecessary IEEE 802.1X authentication cost in WiMAX handoff.
Abstract: The IEEE 802.1X is utilized in mobile Worldwide Interoperability for Microwave Access (WiMAX) authentication. This procedure incurs a long delay in WiMAX handoff. To resolve this issue, this paper proposes a key caching mechanism to eliminate the nonnecessary IEEE 802.1X authentication cost in WiMAX handoff. This mechanism is investigated through analytic and simulation modeling. Our study indicates that the key caching scheme can effectively speed up the handoff process.
24 citations
TL;DR: This study indicates that the proposed power conservation scheme to optimally schedule the awake times among the MSs, such that the number of MSs awaking at the same time is minimal, demonstrates good performance in terms of frame loss and delay time.
Abstract: In IEEE 802.11 wireless networks, a mobile station (MS) can power down the transceiver to save energy. To achieve power conservation, an access point (AP) periodically broadcasts beacons to notify the associated MSs about their traffic indications, and the MSs periodically wake up to listen to the beacons. The MS awake time scheduling is an important issue, which affects the number of simultaneously awake MSs to compete for access. We propose a power conservation scheme to optimally schedule the awake times among the MSs, such that the number of MSs awaking at the same time is minimal. Our study indicates that the proposed scheme demonstrates good performance in terms of frame loss and delay time.
22 citations
TL;DR: It is indicated that the Active Location Reporting scheme may significantly outperform the Location Polling scheme and improve the performance of location tracking.
Abstract: The IP multimedia core network subsystem (IMS) provides multimedia services for Universal Mobile Telecommunications System (UMTS). In IMS, an emergency call is established by an Emergency-Call Session Control Function (ECSCF). The E-CSCF dispatches the call to the nearest public safety answering point (PSAP) according to the location of the caller. After emergency call setup, the caller s location is tracked by the PSAP through Location Polling. This paper investigates the performance of location tracking. Then we propose the active location reporting scheme to improve the performance of location tracking. Our study indicates that the active location reporting scheme may significantly outperform the location polling scheme.
16 citations
18 May 2009
TL;DR: It is indicated that the active location reporting scheme may significantly outperform the location polling scheme and improve the performance of location tracking.
Abstract: The IP Multimedia Core Network Subsystem (IMS) provides multimedia services for Universal Mobile Telecommunications System (UMTS). In IMS, an emergency call is established by an Emergency Call Session Control Function (ECSCF). The E-CSCF dispatches the call to the nearest Public Safety Answering Point (PSAP) according to the location of the caller. After emergency call setup, the caller's location is tracked by the PSAP through Location Polling. This paper investigates the performance of location tracking. Then we propose the Active Location Reporting scheme to improve the performance of location tracking. Our study indicates that the Active Location Reporting scheme may significantly outperform the Location Polling scheme.
16 citations
TL;DR: A third-party solution is proposed that resolves the tromboning problem by replacing two international calls with two local calls and it is shown that this solution is effective in call setup signaling.
Abstract: Existing mobile service providers allow their customers to receive telecommunications services when they roam to other countries. However, in the standard mobile call setup procedure, a call from the visited country to a roaming customer at that country results in two international calls. This phenomenon is referred to as the tromboning effect. In this paper, we propose a third-party solution that resolves the tromboning problem by replacing two international calls with two local calls. Besides huge saving in voice/data path, analytic modeling and simulation experiments indicate that our solution is effective in call setup signaling. Also, our solution does not need to modify the existing mobile telecommunications systems.
14 citations
TL;DR: This paper proposes the Bearer Reservation with Preemption (BRP) scheme to support fast domain transfer, and presents both analytic model and simulation experiments to investigate the BRP performance.
Abstract: Universal Mobile Telecommunications System (UMTS), the core network consists of two service domains: the circuit-switched (CS) and the packet-switched (PS) domains. A UMTS handset can initiate or receive a call in either the CS or the PS domain. During the call, the user may switch from one domain to another. The switching overhead is an important concern of domain transfer. In this paper, we propose the Bearer Reservation with Preemption (BRP) scheme to support fast domain transfer, and present both analytic model and simulation experiments to investigate the BRP performance. Our study indicates that when user behavior is irregular (i.e., either the variance of the domain residence times or the variance of the call holding times is large), the advantage of the BRP scheme becomes significant.
13 citations
TL;DR: This article proposes iP2P, a hybrid P2P system for mobile devices that utilizes the short message service as the control protocol to identify the address of the called peer.
Abstract: Peer-to-peer communications is a major trend in wireless Internet. In a P2P system, the calling peer must identify the network address of the called peer before establishing a P2P connection. This article proposes iP2P, a hybrid P2P system for mobile devices. iP2P utilizes the short message service as the control protocol to identify the address of the called peer. Our approach provides an efficient identification mechanism without the requirement for the maintenance of a centralized registrar server in a hybrid P2P system. We also show how iP2P can integrate effectively with the existing network address translation traversal mechanisms to solve the private IP address issue.
13 citations
Patent•
27 Feb 2009TL;DR: In this article, a gateway for routing an international mobile telephone call comprises a storage device and a cost-saving routing module, which is configured to store a mapping table and a call record table.
Abstract: A gateway for routing an international mobile telephone call comprises a storage device and a cost-saving routing module. The storage device is configured to store a mapping table and a call record table. The mapping table records a mobile phone number of a roaming subscriber and a fixed network number, and the call record table records a caller's phone number and the mobile phone number of the roaming subscriber. The cost-saving routing module is configured to establish a connection in accordance with the mapping table and call record table.
3 citations