DPS: An Architecture for VBR Scheduling in IEEE 802.11e HCCA Networks with Multiple Access Points

  • Dimitrios J. Vergados
  • Dimitrios D. Vergados
  • Christos Douligeris


Recent advances in 802.11 Wireless Local Area Networks (WLANs) have been focused on introducing Quality of Service (QoS) in their performance through the adoption of 802.11e. The Hybrid Controlled Channel Access (HCCA) has been proposed as the mechanism to provide the means for guaranteed QoS in networks controlled by a single Access Point (AP). Moreover, scheduling algorithms have been developed allowing efficient scheduling of Variable Bit Rate (VBR) traffic flows. However, little research may be found regarding the problem of applying HCCA on networks with multiple APs. In this paper, various VBR scheduling mechanisms and methods for multi—AP HCCA are presented and evaluated. In addition, this paper introduces the Dynamic Parallel Scheduler (DPS), a novel HCCA scheduling algorithm for VBR traffic among multiple APs that takes advantage of the rate variability and spatial reuse. DPS’s performance evaluation shows that the proposed scheme achieves improved performance in terms of delay, throughput and packet loss.


HCCA SPC 802.11e scheduling multi-AP coordination 



This paper is part of the 03ED485 - “Design and Development Models for QoS Provisioning in Wireless Broadband Networks” research project, implemented within the framework of the “Reinforcement Programme of Human Research Manpower” (PENED) and co-financed by National and Community Funds (20% from the Greek Ministry of Development-General Secretariat of Research and Technology and 80% from E.U.-European Social Fund).


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Copyright information

© Springer Science+Business Media, LLC 2008

Authors and Affiliations

  • Dimitrios J. Vergados
    • 1
  • Dimitrios D. Vergados
    • 2
    • 3
  • Christos Douligeris
    • 2
  1. 1.School of Electrical and Computer EngineeringNational Technical University of AthensAthensGreece
  2. 2.Department of InformaticsUniversity of PiraeusPiraeusGreece
  3. 3.Department of Information and Communication Systems EngineeringUniversity of the AegeanKarlovassi, SamosGreece

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