Balancing uplink and downlink delay of VoIP traffic in WLANs using Adaptive Priority Control (APC)

ABSTRACT

In IEEE 802.11 wireless networks, the downlink delay rises as the number of VoIP nodes increases while the uplink delay remains small due to the same chance of media access between nodes and the Access Point (AP). This degrades the capacity and QoS of VoIP significantly. Therefore, we introduce Adaptive Priority Control (APC) to balance the downlink and uplink delay of VoIP traffic at the MAC layer, by giving to the AP a higher transmission priority, which is adaptively decided according to the uplink and downlink traffic volume. And, we verify through theoretical analysis that APC is an optimal method to balance the uplink and downlink delay.

REFERENCES

• 1: I. Aad and C. Castelluccia. Differentiation mechanism for IEEE 802.11. In IEEE INFOCOM, pages 209--218, Apr 2001.
• 2: M. Barry, A. T. Campbell, and A. Veres. Distributed control algorithms for service differentiation in wirless packet networks. In IEEE INFOCOM, pages 582--590, Apr 2001.
• 3: Casetti, C. Chiasserini, and C.-F. Improving fairness and throughput for voice traffic in 802.11e EDCA. In Personal, Indoor and Mobile Radio Communications, 2004. PIMRC 2004. 15th IEEE International Symposium, volume 1, pages 525--530, 2004.
• 4: D. J. Deng, R. S. Chang, and A. Veres. A priority scheme for IEEE 802.11 DCF access method. IEICE Trans. Commun., E82-B(1):96--102, Oct 1999.
• 5: IEEE. Wireless LAN Medium Access Control (MAC) and Physical (PHY) specifications, 1999.
• 6: IEEE. Wireless LAN Medium Access Control (MAC) and Physical (PHY) specifications: Higher-Speed Physical Layer Extention in the 2.4 GHz Band, 1999.
• 7: IEEE. IEEE Draft Std. 802.11e, Medium Access Control (MAC) Enhancements for Quality of Service (QoS), D8.0 edition, Feb 2004.
• 8: ITU-T G.114. One-way Transmission Time, 2003.
• 9: ITU-T P.59. Artificial Conversational Speech, 1993.
• 10: R. Jain, D. Chiu, and W. Hawe. A quantative measure of fairness and discrimination for resource allocation in shared computer systems. Technical Report TR-301, DEC, 1984.
• 11: Jiwoong Jeong , Sunghyun Choi , Chong-kwon Kim, Achieving Weighted Fairness between Uplink and Downlink in IEEE 802.11 DCF-Based WLANs, Proceedings of the Second International Conference on Quality of Service in Heterogeneous Wired/Wireless Networks, p.22, August 22-24, 2005 [doi>10.1109/QSHINE.2005.6]
• 12: S. W. Kim, B.-S. Kim, and Y. Fang. Downlink and uplink resource allocation in IEEE 802.11 wireless LANs. IEEE Trans. on Vehicular Technology, 54(1): 320--327, Jan. 2005.
• 13: O. Tickoo and B. Sikdar. Queueing analysis and delay mitigation in IEEE 802.11 random access MAC based wireless networks. In INFOCOM, 2004.
• 14: S. Pilosof, R. Ramjee, D. Raz, Y. Shavitt, and P. Sinha. Understanding TCP fairness over wireless LAN. In IEEE INFOCOM, pages 863--872, Mar 2003.
• 15: QualNet Network Simulator.
• 16: H. Schulzrinne , S. Casner , R. Frederick , V. Jacobson, RTP: A Transport Protocol for Real-Time Applications, RFC Editor, 2003
• 17: TIA. Voice Quality Recommendations for IP Telephony, 2003.
• 18: Xin Gang Wang , Geyong Min , John E. Mellor, Improving VoIP Application's Performance over WLAN Using a New Distributed Fair MAC Scheme, Proceedings of the 18th International Conference on Advanced Information Networking and Applications, p.126, March 29-31, 2004

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:
Performance

Keywords:
IEEE 802.11, QoS, VoIP