1. 27th Aug, 2007Netwrok Research Workshop 2007 1 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.)

2. Netwrok Research Workshop 20072 27th Aug, 2007 Table of Contents 1. Introduction and Motivation Issues on 802.11e and its early studies 2. Feature of 802.11e QoS mechanism 3. Experiments To confirm effectiveness of 802.11e To seek optimum parameter set 4. Summary and Future Plans

3. Netwrok Research Workshop 20073 27th Aug, 2007 1.Introduction and Motivation

4. Netwrok Research Workshop 20074 27th Aug, 2007 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.

5. Netwrok Research Workshop 20075 27th Aug, 2007 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

6. Netwrok Research Workshop 20076 27th Aug, 2007 2.Feature of 802.11e

7. Netwrok Research Workshop 20077 27th Aug, 2007 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

8. Netwrok Research Workshop 20078 27th Aug, 2007 EDCA – MAC layer behavior MAC behavior  Enhanced CSMA/CA AIFS CW TXOP

9. Netwrok Research Workshop 20079 27th Aug, 2007 EDCA – parameters AIFSCWTXOP AC_VO AC_VI AC_BE AC_BK Parameters Priority HIGH LOW

10. Netwrok Research Workshop 200710 27th Aug, 2007 3.Experiments

11. Netwrok Research Workshop 200711 27th Aug, 2007 3 Kinds of Experiments Actual environment  3 wireless nodes of PC I. Default parameters II. Altered parameters Computer simulation  Up to 12 virtual wireless nodes III. Various parameter sets of AIFS, CW, TXOP

12. Netwrok Research Workshop 200712 27th Aug, 2007 Default Setting Performance Background ×2 VoIP (AC_VO) 46.5pt

13. Netwrok Research Workshop 200713 27th Aug, 2007 Altered settings performance 1 Change the parameters independently CW size AIFS TXOP

14. Netwrok Research Workshop 200714 27th Aug, 2007 Altered Settings Performance 2 Gained better performance

15. Netwrok Research Workshop 200715 27th Aug, 2007 3 Kinds of Experiments Actual environment  3 wireless nodes of PC I. Default parameters II. Altered parameters Computer simulation  Up to 12 virtual wireless nodes III. Various parameter sets of CW and TXOP

16. Netwrok Research Workshop 200716 27th Aug, 2007 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

17. Netwrok Research Workshop 200717 27th Aug, 2007 Simulation Resutls – CW size and TXOP CW size TXOP Change the parameters independently

18. Netwrok Research Workshop 200718 27th Aug, 2007 Simulation Resutls – CW size (Up and Down) 90-100 85-90 75-90 75-80 50-55 45-50 5-10 30-35 80-90 70-80 50-60 40-50 30-40 0-10 80-90 70-80 0-10 40-50 10 pair 11 pair12 pair

19. Netwrok Research Workshop 200719 27th Aug, 2007 Simulation Results –TXOPlimit Down Up 10 pair 11 pair12 pair 90-10080-90 70 -80 50-60 60 -70 0 -10 10 -20 30 -40 90-100 80-90 70-80 40 -50 50-60 50 -60 40-50 85 -90 80 -85 75 -80 65 -70 35 -40 50 -55 45 -50 30 -40 10 -20

20. Netwrok Research Workshop 200720 27th Aug, 2007 Simulation Results – CW size and TXOPlimit 10 pairs 12 pairs 11 pairs 90-100 80-90 70 -80 50-60 60-70 0 -10 10 -20 30 -40 50-60 90-100 60-70 80-90 30 -40 0 -10 10 -20 80-90 70-80 60-70 40-50 30 -40 0 -10 10 -20

21. Netwrok Research Workshop 200721 27th Aug, 2007 4.Summary and Future Plans

22. Netwrok Research Workshop 200722 27th Aug, 2007 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

23. Netwrok Research Workshop 200723 27th Aug, 2007 Thank you for your attention!! Q & A

24. Netwrok Research Workshop 200724 27th Aug, 2007 Contact Ryo Kitahara (kitaharar@nttdocomo.co.jp) Service & Solution Development Department NTT DoCoMo, Inc.

25. Netwrok Research Workshop 200725 27th Aug, 2007

26. Netwrok Research Workshop 200726 27th Aug, 2007 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