Test Equipment and Practices Doc.: IEEE 802.11-05-1042/r0 October 2005 November 2005 Test Equipment and Practices Date: 2005-11-03 Authors: 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 <http:// ieee802.org/guides/bylaws/sb-bylaws.pdf>, 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 <stuart.kerry@philips.com> 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 <patcom@ieee.org>. Dennis P. Ward, University of Michigan Dennis P. Ward, University of Michigan

Motivation 802 designed and implemented by network / data engineers Doc.: IEEE 802.11-05-1042/r0 October 2005 Motivation November 2005 802 designed and implemented by network / data engineers 802.11 is a radio network The same rules of network testing don’t necessarily apply The PHY does not terminate at a jack RF requires “new” test equipment What is important in RF testing? Consistency Level of test uncertainty / margin of error Equipment tolerances / parameters Who will be the real “users” of 802.11T? Must establish good practices / parameters in the Recommended Practice! Dennis P. Ward, University of Michigan Dennis P. Ward, University of Michigan

Networking & Data background an End-User Perspective Doc.: IEEE 802.11-05-1042/r0 October 2005 November 2005 Networking & Data background an End-User Perspective 802 Standards Continue to Evolve at all levels Primarily driven by IEEE Computer Society Background involvement by IEEE Microwave Society 802.11, 15, 16, ….. Reflected in Industry of End-Users Network / Data Experts RF relatively new to Computer / Network Community Limited RF / Digital Modulation experience carried over from other industries Dennis P. Ward, University of Michigan Dennis P. Ward, University of Michigan

Doc.: IEEE 802.11-05-1042/r0 October 2005 November 2005 Network Test Methods History with wired tests and equipment to support wired PHY As above with optical fiber Terminations are important No concerns for random interferers Direct connections Losses usually understood and defined Minimal variability Limited amount of test equipment Dennis P. Ward, University of Michigan Dennis P. Ward, University of Michigan

Radio Frequency Test Methods Doc.: IEEE 802.11-05-1042/r0 October 2005 November 2005 Radio Frequency Test Methods Long History for RF engineers, new for network engineers Statistical in nature (Measurement Uncertainty) Specialized Test Equipment Over the air is variable No distinct termination Subject to external interference Subject to multi-path and fading Losses in conducted test environment Insertion loss Return loss Measured losses are subject to test equipment limitations Dennis P. Ward, University of Michigan Dennis P. Ward, University of Michigan

Important RF Test Considerations Doc.: IEEE 802.11-05-1042/r0 October 2005 Important RF Test Considerations November 2005 Specifying Consistency & Repeatability Define test equipment minimum standards Include applicable IEEE standards Define level of expected uncertainty for each test Derived from stack up tolerance analysis Define good RF test practices Define test environment Define minimum data points to report There must be a minimum dataset to report Optional is simply optional What can’t be specified? Specific Vendors / Manufacturers Dennis P. Ward, University of Michigan Dennis P. Ward, University of Michigan

Conformance vs. Performance Doc.: IEEE 802.11-05-1042/r0 October 2005 Conformance vs. Performance November 2005 Differences Minimum standards vs. Reported outcome Performance allows optional parameters Performance allows optional reported data Similarities Both define physical test environment Both define reported data set Both define minimum equipment parameters Both use other standards as part of test definition Seems sensible to apply product test strategies ! Dennis P. Ward, University of Michigan Dennis P. Ward, University of Michigan

Doc.: IEEE 802.11-05-1042/r0 October 2005 November 2005 What role does TGT play? Recommended Performance Practice will be applied at all levels Precedent setting for other 802 standards / practices Insure consistency across the industry Allow “users” to conduct independent and fair evaluations Remove ambiguity in the industry Provide expertise to the industry Dennis P. Ward, University of Michigan Dennis P. Ward, University of Michigan

How can TGT accomplish its goal? Doc.: IEEE 802.11-05-1042/r0 October 2005 November 2005 How can TGT accomplish its goal? Clearly define performance tests Defined set of reported parameters with required minimum data sets Understood and defined measurement uncertainty for each test Define minimum and maximum losses and gains in the system Clearly define test equipment & parameters Define minimum specifications for equipment used in all test Define test equipment settings for each specific test step Specifically identify reference antennas where appropriate Assist “Users” Assume users have an Electrical Engineering background Don’t assume users understand the nuances of RF testing Dennis P. Ward, University of Michigan Dennis P. Ward, University of Michigan

What needs to be added to the Recommended Practice? Doc.: IEEE 802.11-05-1042/r0 October 2005 What needs to be added to the Recommended Practice? November 2005 Improve upon the current draft Defined set of reported parameters with required minimum data sets Understood and defined measurement uncertainty for each test Define allowed minimum and maximum losses and gains in the system Define test equipment settings for each specific test step Include an Appendix or Clause Define minimum specifications for equipment used in all tests Clearly define chamber isolation per existing IEEE standards Clearly define appropriate reference antennas per existing IEEE standards Provide best practices - Include Return Loss Measurements NIST traceable certification as applicable Effects of cable types and length Dennis P. Ward, University of Michigan Dennis P. Ward, University of Michigan

Doc.: IEEE 802.11-05-1042/r0 October 2005 November 2005 Why is this important? 802 Standards are available for free after 6 months Users at all levels will rely on the Recommended Practice: For fair evaluations and performance For interpretation of results For consistency of test set up To understand the differences in test set ups To clearly explain performance metrics Provides credibility to TGT and IEEE Dennis P. Ward, University of Michigan Dennis P. Ward, University of Michigan

First Steps Approve 802.11-04/1540r1 Doc.: IEEE 802.11-05-1042/r0 October 2005 November 2005 First Steps Approve 802.11-04/1540r1 Generally followed, perhaps a formality Suggestions to clarify / improve Document 802.11-05/1044r0 Provides suggested generic definitions Provides suggested supplemental standards Provides suggested minimum standards that any piece of modern equipment can meet Provides suggested test equipment definitions to accompany minimum standards Dennis P. Ward, University of Michigan Dennis P. Ward, University of Michigan