An enhanced HCF for IEEE 802.11e wireless networks

ABSTRACT

In this paper the behavior of the upcoming MAC protocol for wireless LANs IEEE 802.11e is investigated. Based on the results, we propose an enhancement for Hybrid Coordination Function (HCF) to improve its Admission Control Unit (ACU). The analysis of Enhanced Distributed Channel Access (EDCA) and HCF schemes is performed for different network sizes. Three types of traffic - voice, video and bursty data - are considered in this analysis. Four metrics - transfer delay, jitter, throughput and packet loss - are considered in studying the behavior of these schemes. It is shown that EDCA does well for small to moderate network, whereas HCF performs better for larger networks. However, bursty traffic received very poor service from both schemes, and likely to starve in a heavily loaded system. The performance of the proposed scheme is evaluated through ns-2 simulator and then compared against the standard schemes in 802.11e. Our enhanced HCF (eHCF) shows fairness in allocating bandwidth to different priority classes by employing the Class-Based Queuing - like mechanism in its ACU.

REFERENCES

• 1: "Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications," IEEE 802.11 standard, 1997.
• 2: IEEE Std 802.11e/D4.3 May 2003 Draft Supplement to IEEE standard for Telecommunications and Information exchange between systems - LANMAN specific requirements. Part 11: wireless LAN Medium Access Control (MAC) and Physical Layer (PHY).
• 3: ns-2 simulation tool home page - <http://www.isi.edu/nsnam/ns/> .
• 4: Code for ns-2 with PCF functionality - <http://www.sm.luth.se/~dugdale/>
• 5: Code for IEEE 802.11e - <http://www-sop.inria.fr/planete/qni/fhcf/>.
• 6: Anders Lindgren, Andreas Almquist, and Olov Schelén. "Quality of Service Schemes for IEEE 802.11 - A Simulation Study", Department of Computer Science and Electrical Engineering Lulea University of Technology, Sweden.
• 7: Anders Lindgren, Andreas Almquist, and Olov Schelén. "Quality of Service Schemes for IEEE 802.11 - An Evaluation", Department of Computer Science and Electrical Engineering Lulea University of Technology, Sweden.
• 8: H.L. Truong, G. Vannuccini, "The IEEE 802.11e MAC for Quality of Service in Wireless LANs", IBM Research Zurich Research Laboratory, Switzerland.
• 9: Priyank Garg, Rushabh Doshi, Russell Greene, Marry baker, Majid Baker, Majid Malek, Xiaoyan Cheng, "Using IEEE 802.11e MAC for QoS over Wireless", Computer Science Department, Stanford University.
• 10: Pierre Ansel, Qiang Ni, Thierry Turletti, "FHCF: A Fair Scheduling Scheme for 802.11e WLAN", Projet Planete, July 2003.
• 11: Stefan Mangold, Sunghyun Choi, Peter May, Ole Klein, Guido Hiertz, Lothar Stibor, "IEEE 802.11e Wireless LAN for Quality of Service ", Philips Research Germany, Germany.
• 12: Sally Floyd , Van Jacobson, Link-sharing and resource management models for packet networks, IEEE/ACM Transactions on Networking (TON), v.3 n.4, p.365-386, Aug. 1995 [doi>10.1109/90.413212]
• 13: A. Grilo, M. Macedo, M. Nunes, "A Scheduling Algorithm for QoS Support in IEEE 802.11e Networks", IEEE Wireless Communications, Vol.10, No.3, June 2003, pp36--43.
• 14: A. Grilo, M. Nunes, "Performance evaluation of IEEE 802.11e", INESC/IST, R. Alves Redol, N°9, 1000 Lisboa, Portugal.
• 15: Ns documentation - <http://www.isi.edu/nsnam/ns/ns-documentation.html> .
• 16: NS by Example - Proposal - <http://nile.wpi.edu/NS/>
• 17: Class-based queuing - <http://www.nwfusion.com/details/656.html> .
• 18: D. Clark and V. Jacobson, "Flexible and Efficient Resource Management for Datagram Networks", unpublished manuscript, April 1991.

INDEX TERMS

Primary Classification:
  C. Computer Systems Organization
  C.2 COMPUTER-COMMUNICATION NETWORKS
      C.2.1 Network Architecture and Design
          Subjects: Wireless communication

Additional Classification:
  I. Computing Methodologies
  I.6 SIMULATION AND MODELING
      I.6.6 Simulation Output Analysis

General Terms:
Experimentation, Performance

Keywords:
IEEE 802.11e, admission control, hybrid coordination function (HCF), quality of service, scheduling