Browsing by Author "Huang, Shih-Chang"

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A power-saving scheduling for infrastructure-mode 802.11 wireless LANs
(2006-11-08)
Lin, Hsiao-Po
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Huang, Shih-Chang
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Jan, Rong-Hong
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資訊工程學系
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Department of Computer Science
This paper presents a novel method to arrange wakeup schedule for sleeping stations such that the number of wakeup stations in each beacon interval is balanced in IEEE 802.11 wireless local area networks (WLANs). This method reduces the probability of collision and thus the station can save more power. Next, we consider how to poll the wakeup stations to send the PS-Poll frame to get back their buffered data so that the contention can be avoided. Three different access scheduling mechanisms are proposed for the contention avoidance. In the first mechanism, only one of wakeup stations is scheduled to access the buffered data. The second and third mechanisms based on the smallest association ID (AID) first and the smallest queue length first, respectively, arrange a subset of wakeup stations to get back their buffered data within a beacon interval. Simulation results show that the proposed methods are effective in the power-saving. (c) 2006 Elsevier B.V. All rights reserved.
An Energy-Efficient Scheduling for Multiple MSSs in IEEE 802.16e Broadband Wireless
(2008)
Huang, Shih-Chang
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Chen, Chien
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Jan, Rong-Hong
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Hsieh, Cheng-Chung
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資訊工程學系
This paper proposes an energy-efficient traffic scheduling approach for 802.16e broadband wireless networks. Instead of considering a single Mobile Subscriber Station (MSS) as most of the current researchers do, multiple MSSs are considered in our work. The constant bit rate traffic with QoS delay constraint is considered in this paper. The proposed approach considers both energy efficiency and bandwidth utilization. First, we derive a minimum wakeup time for each MSS to achieve the maximum power saving by waking up the minimum number of time slots. After then, we interleave the traffic of multiple MSSs by taking advantage of feasible slot allocation. In order to support the maximum number of MSSs, our scheduling problem can be transformed into a maximum bipartite matching problem. We use the Ford-Fulkerson maximum flow algorithm to obtain a feasible schedule for multiple MSSs. Simulation results show that our proposed approach has better bandwidth utilization and achieves maximum energy saving.
SCPS: A self-configuring power-saving protocol for wireless ad hoc networks
(2008-04-24)
Huang, Shih-Chang
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Jan, Rong-Hong
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Yang, Wuu
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資訊工程學系
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Department of Computer Science
SCPS is a novel self-configuring power-saving protocol for wireless one-hop ad hoc networks. According to IEEE 802.11 WLAN standard, a station may enter a special power-saving (PS) mode. SCPS allows all stations in the PS mode to adjust their wakeup schedules whenever a station enters or exits the PS mode. The adjustment can balance the number of wakeup, stations in each beacon interval so that the contention for transmission medium and the collisions in transmission will be ameliorated, which results in more efficient energy usage. Simulation results show that SCPS successfully balances the number of stations that wake up in each beacon interval, increases the sleep ratio, and reduces the collision probability. The combined effect reduces total energy consumption. (C) 2008 Elsevier B.V. All rights reserved.