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Optimum Parameters for VoIP in IEEE 802.11e Wireless LAN

Optimum Parameters for VoIP in IEEE 802.11e Wireless LAN. APAN Network Research Workshop 2007 August 27 th , 2007 Sheraton Xi’an Hotel, China Ryo Kitahara (NTT DoCoMo) Koichiro Doi, Tomoya Iinuma, Shingo Morita, Shigeki Goto (Waseda Univ.). Table of Contents. Introduction and Motivation

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Optimum Parameters for VoIP in IEEE 802.11e Wireless LAN

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  1. Optimum Parameters for VoIP in IEEE 802.11e Wireless LAN APAN Network Research Workshop 2007 August 27th, 2007 Sheraton Xi’an Hotel, China Ryo Kitahara (NTT DoCoMo) Koichiro Doi, Tomoya Iinuma, Shingo Morita, Shigeki Goto (Waseda Univ.) Netwrok Research Workshop 2007

  2. Table of Contents • Introduction and Motivation Issues on 802.11e and its early studies • Feature of 802.11e QoS mechanism • Experiments To confirm effectiveness of 802.11e To seek optimum parameter set • Summary and Future Plans Netwrok Research Workshop 2007

  3. Introduction and Motivation Netwrok Research Workshop 2007

  4. Introduction • Deployments as network infrastructure • Home and office LAN • Public internet access e.g. airport and railway station • AP sharing services such as FON • Applications over 802.11 • Non-realtime: WWW, E-mail, short message • Realtime: Video streaming, IP telephony (VoIP)  QoS functions i.e. 802.11e has been introduced. Netwrok Research Workshop 2007

  5. Motivation • Issues on 802.11e • A few parameters to set • AIFS, CW, TXOP • Not always suitable for each application • Default parameter set depends on manufacturers’ implementation.  A lot of early studies to resolve issues and improve packet-level QoS. • Our approach • Seek optimum parameter set from the perspective of user-level QoS. • By 3 kinds of experiments with working test-beds Netwrok Research Workshop 2007

  6. Feature of 802.11e Netwrok Research Workshop 2007

  7. What is IEEE 802.11e ? • An Extension to IEEE 802.11 a/b/g • Quality of Service Enhancement • QoS Guarantee • HCCF – rarely implemented • QoS Classification • EDCA – common implementation of “IEEE 802.11e enabled” Access Points Netwrok Research Workshop 2007

  8. EDCA – MAC layer behavior • MAC behavior • Enhanced CSMA/CA AIFS CW TXOP Netwrok Research Workshop 2007

  9. EDCA – parameters Parameters HIGH Priority LOW Netwrok Research Workshop 2007

  10. Experiments Netwrok Research Workshop 2007

  11. 3 Kinds of Experiments • Actual environment • 3 wireless nodes of PC • Default parameters • Altered parameters • Computer simulation • Up to 12 virtual wireless nodes • Various parameter sets of AIFS, CW, TXOP Netwrok Research Workshop 2007

  12. Default Setting Performance 46.5pt Background ×2 VoIP (AC_VO) Netwrok Research Workshop 2007

  13. Altered settings performance 1 • Change the parameters independently AIFS TXOP CW size Netwrok Research Workshop 2007

  14. Altered Settings Performance 2 • Gained better performance Netwrok Research Workshop 2007

  15. 3 Kinds of Experiments • Actual environment • 3 wireless nodes of PC • Default parameters • Altered parameters • Computer simulation • Up to 12 virtual wireless nodes • Various parameter sets of CW and TXOP Netwrok Research Workshop 2007

  16. S11 Bi-directional VoIP flows C11 Simulation Setup Desmo-J (General-purpose library) Fixed nodes: up to 12 Wireless nodes: up to 12 PHY Layer: 11Mbps@802.11b VoIP flows in each direction: up to 12 Payload size: 160bytes Queue length for EDCA: 200 frames Netwrok Research Workshop 2007

  17. Simulation Resutls – CW size and TXOP • Change the parameters independently CW size TXOP Netwrok Research Workshop 2007

  18. Simulation Resutls – CW size (Up and Down) 90-100 85-90 90-100 75-90 80-90 75-80 50-55 80-90 50-60 45-50 70-80 40-50 70-80 40-50 30-35 30-40 0-10 5-10 0-10 10 pair 11 pair 12 pair Netwrok Research Workshop 2007

  19. Simulation Results –TXOPlimit Down 90-100 90-100 10 -20 10 -20 30 -40 40 -50 0 -10 50-60 10 pair 11 pair 12 pair Up 35 -40 50 -55 60 -70 80-90 80 -85 90-100 80-90 90-100 70 -80 85 -90 45 -50 75 -80 50 -60 65 -70 30 -40 40-50 70-80 50-60 Netwrok Research Workshop 2007

  20. Simulation Results – CW size and TXOPlimit 90-100 80-90 11 pairs 10 -20 30 -40 60-70 0 -10 50-60 10 pairs 12 pairs 70 -80 80-90 90-100 80-90 10 -20 70-80 60-70 10 -20 30 -40 30 -40 40-50 60-70 0 -10 50-60 0 -10 50-60 Netwrok Research Workshop 2007

  21. Summary and Future Plans Netwrok Research Workshop 2007

  22. Summary and Future Plans • Summary • 3 kinds of experiments showed that; • Effectiveness of EDCA • Tendency of optimal parameter sets for VoIP • Future plans • Seeking optimal parameter sets for traffic mixed with real-time and non real-time • Development of algorithmic or parameter-tuning method to change parameters adaptively Netwrok Research Workshop 2007

  23. Thank you for your attention!! Q & A Netwrok Research Workshop 2007

  24. Contact Ryo Kitahara (kitaharar@nttdocomo.co.jp) Service & Solution Development Department NTT DoCoMo, Inc. Netwrok Research Workshop 2007

  25. Netwrok Research Workshop 2007

  26. VoIP: Quality Measurement Issues • Packet-level indicators do NOT necessarily directly reflect voice quality. • R value • Voice quality • Established comparison with PSTN phone quality • Established conversion with MOS, another voice quality indicator Netwrok Research Workshop 2007

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