1. doc.: IEEE 802.11-05/1109r1 Submission November 2005 Fanny Mlinarsky, et alSlide 1 Framework for Testing Latency Sensitive Use Cases Notice: This document has been prepared to assist IEEE 802.11. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that this contribution may be made public by IEEE 802.11. Patent Policy and Procedures: The contributor is familiar with the IEEE 802 Patent Policy and Procedures, including the statement "IEEE standards may include the known use of patent(s), including patent applications, provided the IEEE receives assurance from the patent holder or applicant with respect to patents essential for compliance with both mandatory and optional portions of the standard." Early disclosure to the Working Group of patent information that might be relevant to the standard is essential to reduce the possibility for delays in the development process and increase the likelihood that the draft publication will be approved for publication. Please notify the Chair as early as possible, in written or electronic form, if patented technology (or technology under patent application) might be incorporated into a draft standard being developed within the IEEE 802.11 Working Group. If you have questions, contact the IEEE Patent Committee Administrator at.http:// ieee802.org/guides/bylaws/sb-bylaws.pdfstuart.kerry@philips.compatcom@ieee.org Date: 2005-11-09 Authors:

2. doc.: IEEE 802.11-05/1109r1 Submission November 2005 Fanny Mlinarsky, et alSlide 2 Abstract This presentation proposes a framework for testing Latency Sensitive Usage Cases (LSUCs) over 802.11 interfaces.

3. doc.: IEEE 802.11-05/1109r1 Submission November 2005 Fanny Mlinarsky, et alSlide 3 Outline Definition of LSUC Examples of LSUCs Voice – A An Example –Primary Metrics –Secondary Metrics Proposed 802.11 LSUC Framework Summary References

4. doc.: IEEE 802.11-05/1109r1 Submission November 2005 Fanny Mlinarsky, et alSlide 4 Definition of LSUC Latency Sensitive Usage Cases (LSUCs) are applications whose functionality depends on and is affected by packet loss, packet delay and packet jitter across any and all networks traversed. LSUCs frequently send/receive packets at a constant packet rate. Examples include VOIP, Video Conferencing, Internet Gaming.

5. doc.: IEEE 802.11-05/1109r1 Submission November 2005 Fanny Mlinarsky, et alSlide 5 Example: VOIP PC-to-PC or PC-to-PSTN (services like Skype) 802.11 Handsets Broadband Phone Service Enterprise VOIP Networks Metropolitan MESH VOIP Networks

6. doc.: IEEE 802.11-05/1109r1 Submission November 2005 Fanny Mlinarsky, et alSlide 6 Voice over WiFi Examples Home –Streaming Video –Broadband Voice –Appliance Control –Video Gaming SOHO –WiFi or WiFi-Cell handset, soft phone –Service providers –No handoff, low capacity, basic security –Range Enterprise –WiFi or WiFi-Cell handset, soft phone –Range –Handoff speed –Call capacity –Security Public access (WiFi hotspots) –WiFi-Cell handset, soft phone –Range –Call Capacity –Roaming issues WiFi handset

7. doc.: IEEE 802.11-05/1109r1 Submission November 2005 Fanny Mlinarsky, et alSlide 7 Primary Voice Metrics –MOS (mean opinion score) uses a wide range of human subjects to provide a subjective quality score (ITU-T P.800) –PESQ (perceptual speech quality measure) sends a voice pattern across a network and then compares received pattern to the original pattern and computes the quality rating (ITU-T P.862) –E-Model computes Rating Factor or R-Factor as a function of delay and packet loss; R-Factor directly translates into MOS (ITU-T G.107) ITU-T Voice Quality Standards

8. doc.: IEEE 802.11-05/1109r1 Submission November 2005 Fanny Mlinarsky, et alSlide 8 ITU-T PESQ Model

9. doc.: IEEE 802.11-05/1109r1 Submission November 2005 Fanny Mlinarsky, et alSlide 9 E-Model based on ITU-T G.107 Packet-loss Latency ITU-T E-Model

10. doc.: IEEE 802.11-05/1109r1 Submission November 2005 Fanny Mlinarsky, et alSlide 10 E-Model Parameters Latency 500 ms max Packet loss 20% max

11. doc.: IEEE 802.11-05/1109r1 Submission November 2005 Fanny Mlinarsky, et alSlide 11 Primary LSUC Metrics  Vary depending on application.  R-Factor and PESQ are commonly used for voice  Some LSUCs do not have any primary metrics defined (i.e., internet gaming)  Devices/systems under test  Client  AP  Multi-AP infrastructure (e.g. mesh)

12. doc.: IEEE 802.11-05/1109r1 Submission November 2005 Fanny Mlinarsky, et alSlide 12 Secondary Metrics Secondary Metrics for LSUCs are: –Packet Loss –Packet Delay (in microseconds) –Jitter (RFC 1889) Packet Loss is measured in each direction (upstream / downstream) separately. Ideally, it should be measured from both endpoints – i.e., the transmitter and the receiver. Packet Delay should be measured in each direction (upstream / downstream) separately in microseconds. Jitter should be measured in microseconds according to RFC 1889

13. doc.: IEEE 802.11-05/1109r1 Submission November 2005 Fanny Mlinarsky, et alSlide 13 Proposed LSA Testing Framework TGt should reference applicable Primary Metrics where possible. Should TGt recommend specific primary metrics, or is that too contentious? Use packet delay, loss and jitter as the secondary metrics for LSUC. Are there potentially other application specific secondary metrics? TGt should define the 802.11 test variables that will directly impact the Primary LSUC metrics. For example: –Signal strength –Traffic load –BSS Transitions / Fast BSS Transitions –PS-Poll / APSD –802.11e and 802.11i specific device and system settings

14. doc.: IEEE 802.11-05/1109r1 Submission November 2005 Fanny Mlinarsky, et alSlide 14 Discussion Is this framework acceptable? Should this framework be used as a basis to draft a submission into TGt ?

15. doc.: IEEE 802.11-05/1109r1 Submission November 2005 Fanny Mlinarsky, et alSlide 15 References 11-05/949r0, “Latency-Sensitive-Application Metrics”, S. Bangolae 11-05/33r0, “Performance of Voice over 802.11 Networks”, Fanny Mlinarsky 11-05/887r0, “Video Testing Strategy”, P. Corriveau, et al 11-05-/177r0, “Dell IEEE 802.11 TGT Output”, P. Mehta, et al