Browsing by Author "Chen, You-Lin"

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A Low-Latency Scanning with Association Mechanism for Real-Time Communication in Mobile WiMAX
(2012-10-01)
Chen, You-Lin
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Tsao, Shiao-Li
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資訊工程學系
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Department of Computer Science
In Mobile WiMAX, a mobile station (MS) scans neighboring base stations (BSs) before conducting handover. The MS may perform the association further, i.e., initial ranging, with neighboring BSs during scanning to obtain ranging parameters and/or service availability information for a potential handover to a BS and/or the selection of target BSs. However, the scanning with association scheme may introduce additional latency for handover. This study first evaluates the conventional scanning with association process, and then proposes a mechanism to reduce the association latency. The performance models of the proposed mechanism are presented and the accuracies of analytical models are verified by simulations. Results demonstrate that the proposed mechanism reduces the association latency by 61.9%-78.0% for audio services and 41.3%-65.4% for video services.
Energy-efficient packet scheduling algorithms for real-time communications in a mobile WiMAX system
(2008-06-25)
Tsao, Shiao-Li
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Chen, You-Lin
;
資訊工程學系
;
Department of Computer Science
Broadband wireless access systems usually provide flexible sleep-mode operations for mobile stations to conserve their energy during idle or active mode. For example, Mobile WiMAX, i.e. the IEEE 802.16e, offers several power-saving classes that can be associated with different types of network connections to minimize power consumption of mobile stations. Unfortunately, previous studies did not fully utilize the sleep-mode features to save the energy of a mobile station with multiple real-time connections, and power consumption of a mobile station is not yet optimized. In this work, two energy-efficient packet scheduling algorithms for real-time communications in a Mobile WiMAX system are proposed. The schemes not only guarantee the quality of services (QoSs) of real-time connections but also minimize power consumption of mobile stations. Simulation results demonstrate that the proposed schemes outperform the traditional approach. (C) 2008 Elsevier B.V. All rights reserved.
Energy-efficient Sleep-mode Operations for Broadband Wireless Access Systems
(2006)
Chen, You-Lin
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Tsao, Shiao-Li
;
資訊工程學系
;
Department of Computer Science
Broadband wireless access systems usually provide flexible sleep-mode operations for mobile stations to conserve energy during idle or active modes. For example, the IEEE 802.16e offers several sleep-mode classes that can be applied to mobile subscriber stations (MSSs) to reduce their power consumptions for different applications. Unfortunately, previous studies did not fully utilize sleep-mode features, and the power consumption of an MSS with multiple network connections is not optimized. In this work, two scheduling algorithms for sleep-mode operations based on the IEEE 802.16e are proposed. These schemes guarantee the quality of services (QoSs) of the network connections for an MSS and also minimize the power consumption of the MSS. Simulation results demonstrate that the proposed schemes outperform the traditional approaches.
Evaluation of Scan and Association Process for Real-Time Communication in Mobile WiMAX
(2010-11-01)
Tsao, Shiao-Li
;
Chen, You-Lin
;
Chang, Chia-Hsiang
;
資訊工程學系
;
Department of Computer Science
One of the most important issues in offering real-time communication services in a mobile environment is support for seamless handover between base stations during a communication session. In Mobile WiMAX, a mobile station may have to perform a scan and association process before handover, but unfortunately, this scan and association process introduces service disruption. In this letter, we investigate the scan and association latency in Mobile WiMAX, and evaluate its performance through analytic models and simulations.
Evaluation of Scan and Association Process for Real-Time Communication in Mobile WiMAX
(2010-11-01)
Tsao, Shiao-Li
;
Chen, You-Lin
;
Chang, Chia-Hsiang
;
資訊工程學系
;
Department of Computer Science
One of the most important issues in offering real-time communication services in a mobile environment is support for seamless handover between base stations during a communication session. In Mobile WiMAX, a mobile station may have to perform a scan and association process before handover, but unfortunately, this scan and association process introduces service disruption. In this letter, we investigate the scan and association latency in Mobile WiMAX, and evaluate its performance through analytic models and simulations.