doc.: IEEE /1202r1 Submission October 2004 C. Wright, Azimuth SystemsSlide 1 Proposed Metrics for TGT and Call to Action Date: Oct 21, 2004 Author: Charles R. Wright Azimuth Systems Acton, MA Ph:

doc.: IEEE /1202r1 Submission October 2004 C. Wright, Azimuth SystemsSlide 2 Introduction We’ve talked in a lot of generalities about aspects of wireless performance that impact the user experience These can be translated into specific metrics –With corresponding test environments, etc. We need to get down to the business of –Defining the metric –Documenting the measurement methodology This presentation tries to provide a condensed list of metrics

doc.: IEEE /1202r1 Submission October 2004 C. Wright, Azimuth SystemsSlide 3 Presentations driving this one 11-04/987r0, “A First Stab at Metrics,” Mandeville 11-04/989r1, “Metrics for Characterizing BSS Transition Time Performance,” Wright, Polanec 11-04/1009r1, “Framework, Usages, Metrics Proposal for TGT,” Mehta, et al 11-04/1017, “Comments on Wireless Performance & Prediction Metrics,” Kobayashi, et al 11-04/1157r0, “A Metrics and Methodology Starting Point for TGT,” Wright 11-04/1156r1, “Bottom-Up Evaluation of Performance Testing,” Foegelle

doc.: IEEE /1202r1 Submission October 2004 C. Wright, Azimuth SystemsSlide 4 What metrics need to be defined? Several categories –Link layer –Physical layer –Combined Link/Physical layer –Antenna performance – link management related –Whole device Two kinds of equipment –Access points –Client stations Environment types –Define environments that are appropriate to the specific metric

doc.: IEEE /1202r1 Submission October 2004 C. Wright, Azimuth SystemsSlide 5 Link Layer Metrics Goal of these metrics is to measure device performance under optimum conditions –“Line of sight” – no multipath –Conducted tests to avoid interference problems –Need to specify security, QoS features in use “Throughput” –Max forwarding rate, forwarding rate at max offered load (FRMOL) –TCP data throughput MSDU loss –Loss after wireless link retries –A function of offered load or only at maximums? Delay (latency) –Definitely applicable to APs –Client applicability? Measurability? Jitter –Same comment as for delay

doc.: IEEE /1202r1 Submission October 2004 C. Wright, Azimuth SystemsSlide 6 Physical Layer Metrics Receiver sensitivity at each PHY rate –Definitely measured without multipath (“line-of-sight”) –Probably measured with multipath, too Adjacent channel interference at each PHY rate –Definitely measured without multipath (“line-of-sight”) –Probably not measured with multipath Applicable to all devices Questions –Other PHY layer metrics? –Which multipath models? –Are these tests only performable using “radio control” software?

doc.: IEEE /1202r1 Submission October 2004 C. Wright, Azimuth SystemsSlide 7 Combined Link/Physical Layer “Rate versus Range” –Throughput versus input signal level –Needs a good definition Diversity performance –Waiting for an expert to consider such a test Questions –Hmmm…

doc.: IEEE /1202r1 Submission October 2004 C. Wright, Azimuth SystemsSlide 8 Antenna Performance Single antenna pattern –One for each antenna? Applicable to all devices Questions –How do we deal with antenna loading caused by humans or other stuff? –How do we characterize “smart” antennas? –This slide has too much white space on it!

doc.: IEEE /1202r1 Submission October 2004 C. Wright, Azimuth SystemsSlide Link Management Related AP Association Capacity, Association Rate –How many clients can an AP support? How fast does the AP associate them? –Variables: authentication method Transition time metric –How fast does “roaming” algorithm work? –Likely we should wait until TGr is more solid –Is it a station, AP or system test? Other metrics related to TGk –We need to investigate this – I have no idea what metrics might be needed, if any

doc.: IEEE /1202r1 Submission October 2004 C. Wright, Azimuth SystemsSlide 10 Whole Device Tests Don’t know if we actually want or need this, but it’s here so we don’t forget it Rate vs. Range test done here too? Anechoic Chamber Device Bidirectional Multipath Simulator DUT Adjacent Channel Intereferer V.A. = RF signal path Traffic Generator & Analyzer Ethernet

doc.: IEEE /1202r1 Submission October 2004 C. Wright, Azimuth SystemsSlide 11 Other Issues How do “AP aggregation” systems fit into TGT? How does DC power consumption fit into TGT?

doc.: IEEE /1202r1 Submission October 2004 C. Wright, Azimuth SystemsSlide 12 Conclusions There is quite a list of metrics! Let’s get people to take responsibility for some of them ►Want to see proposals or at least discussions of all these metrics during the 14 hours of meeting time in San Antonio

doc.: IEEE /1202r1 Submission October 2004 C. Wright, Azimuth SystemsSlide 13 Appendix

doc.: IEEE /1202r1 Submission October 2004 C. Wright, Azimuth SystemsSlide 14 How to get your proposal into the draft 1.Write your proposal Describe in a MSWord document a list of “instructions to the editor” (aka “draft normative text”). For whole new sections, this will likely be 100% new text/figures. Create a Powerpoint presentation based on above to describe the salient details to the group 2.Submit both docs to server at least 4 session hours before intent to vote on proposal The “4-hour rule” is part of rules and is strenuously enforced Why? It gives people time to read, understand and consider the proposal TGT can also rule that longer period of time is required Helpful to announce existence of the documents through the reflector 3.Make presentation before the group 4.Make motion to accept proposal (the “draft normative text”) into the draft 75% majority required for any changes to a draft (additions/changes/deletions) If approved by group, editor will incorporate into the draft

doc.: IEEE /1202r1 Submission October 2004 C. Wright, Azimuth SystemsSlide 15 Rules about Drafts Offical drafts are owned by IEEE and available only to –Voting members (through – meeting attendees ( at the meeting onlyhttp:// In other words, you will need to be a voting member or come to the meetings to get current copies of the draft!