Minimizing energy consumption with QoS constraints over IEEE 802.16e networks

  • Authors:

  • C. -Y. Wu;H. -J. Ho;S. -L. Lee

  • Affiliations:

  • Department of Computer Science and Information Engineering, National Chung Cheng University, 168, University Rd., Minsyong, Chiayi 621, Taiwan;Department of Applied Digital Media, WuFeng University, 117, Section 2, Jianguo Rd., Minsyong, Chiayi 621, Taiwan;Department of Computer Science and Information Engineering, National Chung Cheng University, 168, University Rd., Minsyong, Chiayi 621, Taiwan

  • Venue:
  • Computer Communications
  • Year:
  • 2012

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Abstract

This paper studies an optimization problem for real-time flows scheduling with QoS guarantees over IEEE 802.16e WiMAX networks. Each mobile station may have one or more real-time flows that have specific QoS requirements, including bandwidth requirements and delay bounds. Since flows have different arrival rates, the mobile station turns off the transceiver and enters sleep mode to save energy only when it does not need to either receive or send traffic. For minimizing the energy consumption, we are required to schedule all flows efficiently according to the QoS requirements to increase the sleep interval. We formulate the scheduling problem as an Integer Linear Program (ILP) to minimize the total number of active frames to save energy consumption. A heuristic algorithm, called adaptive bandwidth reservation (ABR), is also proposed to improve the computing efficiency. The approximation factor of 2 is proved in the worst case analysis of the ABR algorithm. Our approaches not only guarantee the QoS for real-time flows, but also minimize energy consumption of mobile stations. The proposed approach provides significant improvement on throughput and energy saving for the mobile station. Experiment results demonstrate that the ABR algorithm outperforms the previous approaches in terms of energy saving, bandwidth utilization and drop rate.