Service Interval Optimization with Delay Bound Guarantee for HCCA in IEEE 802.11e WLANs

• FORONDA Augusto

  Faculty of Engineering, Kobe University

• HIGUCHI Yuhi

  Faculty of Engineering, Kobe University

• OHTA Chikara

  Faculty of Engineering, Kobe University

• YOSHIMOTO Masahiko

  Faculty of Engineering, Kobe University

• OKADA Yoji

  Information and Communication Laboratories, Sumitomo Electric Industries

Abstract

IEEE802.11e Medium Access Control (MAC) is a supplement to the IEEE802.11 Wireless Network (WLAN) standard to support Quality of Service (QoS). The 802.11e MAC defines a new coordination function, namely Hybrid Coordination Function (HCF), which takes the QoS requirements of flows into account and allocates Transmission Opportunity (TXOP) to stations. On the basis of mean sending rate, delay of Variable Bit Rate (VBR) traffic cannot be bounded with the reference HCF scheduling algorithm proposed in this supplement. In this paper, we propose a new Connection Admission Control (CAC) and a scheduling algorithm that utilize the token bucket and a modified Latency-Rate (LR) scheduling algorithm to guarantee a bounded delay for HCF Controlled Channel Access (HCCA). The new Service Interval (SI) is calculated to optimize the number of stations accommodated and takes into account delay bound and token bucket parameters. We show that it is possible to obtain worst-case performance guarantees on delay. First, we analyze the behavior of the new scheduler with a loss free wireless channel model and after this, with a burst loss model and we explain how it is possible to extend this scheduler for a multi-rate scheme. Properties of the proposal are investigated both theoretically and using ns-2 simulations. We present a set of simulations with both Constant Bit Rate (CBR) and VBR flows and performance comparisons with HCF scheduling algorithm. The results show that the delay upper bound can be achieved for a large range of networks load with bandwidth optimization.

Journal

• IEICE Trans. Commun., B

  IEICE Trans. Commun., B 90 (11), 3158-3169, 2007-11-01

  The Institute of Electronics, Information and Communication Engineers

Keywords

• wireless network
• bandwidth optimization
• bounded delay
• scheduler

Details

• CRID: 1570009752661614848
• NII Article ID: 110007538332
• NII Book ID: AA10826261
• ISSN: 09168516
• Text Lang: en
• Data Source:
  • CiNii Articles