A controlled-access scheduling mechanism for QoS provisioning in IEEE 802.11e wireless LANs

ABSTRACT

Wireless Local Area Networks (WLAN) are being deployed at a rapid pace and in different environments. As a result, the demand for supporting a diverse range of applications over wireless access networks is becoming increasingly important. In particular, multimedia applications, such as Video and Voice, have specific delay and bandwidth requirements that cannot be fulfilled by the current IEEE 802.11-based WLANs. To overcome this issue, new enhancements are being introduced to the Medium Access Control (MAC) layer of the 802.11 standard under the framework of the IEEE 802.11e standard which is still a work in progress. The 802.11e standard offers new features for supporting Quality of Service (QoS) in the MAC layer, it however does not mandate a final solution for QoS issues and intentionally leaves it to the implementers to devise their own methods using the available features. We present a solution that employs the controlled access features of the 802.11e to provide per-session guaranteed quality-of-service. Our design comprises of a scheduler that assign guaranteed service times to individual sessions using a fair scheduling algorithm. We show that the proposed solution outperforms other methods that are contention and priority based.

REFERENCES

• 1: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications. ANSI/IEEE Std 802.11: 1999 (E) Part 11, ISO/IEC 8802-11, 1999.
• 2: IEEE Draft Std. 802.11e/D8.0, "Medium Access Control (MAC) Quality of Service (QoS) Enhancements," Feb. 2004.
• 3: Yaser Pourmohammadi Fallah , Anwar Elfeitori , Hussein Alnuweiri, A Unified Scheduling Approach for Guaranteed Services over IEEE 802.11e Wireless LANs, Proceedings of the First International Conference on Broadband Networks (BROADNETS'04), p.375-384, October 25-29, 2004 [doi>10.1109/BROADNETS.2004.14]
• 4: J. Rosenberg, et.al., "SIP: Session Initiation Protocol", RFC 3261, June 2002
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• 7: Pattara-Atikom, W.; Krishnamurthy, P.; Banerjee, S.; "Distributed mechanisms for quality of service in wireless LANs", Wireless Communications, IEEE, Volume: 10, Issue: 3, June 2003 Pages: 26 -- 34
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• 10: Pourmohammadi Fallah Y., Alnuweiri H., "Enhanced Controlled-Access and Contention-Based Algorithms for IEEE 802.11e Wireless LAN",to appear in proceeding of Wirelesscom 2005, Int. Conf. on Wireless Networks, Communications, and Mobile Computing, June 2005

INDEX TERMS

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

General Terms:
Algorithms, Design

Keywords:
802.11e, QoS, WFQ, multimedia over WLAN, virtual packet scheduling, wireless LAN