1. Test Equipment and Practices
Doc.: IEEE /r0
October 2005
November 2005
Test Equipment and Practices
Date:
Authors:
Notice: This document has been prepared to assist IEEE 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.
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Dennis P. Ward, University of Michigan
Dennis P. Ward, University of Michigan

2. Motivation 802 designed and implemented by network / data engineers
Doc.: IEEE /r0
October 2005
Motivation
November 2005
802 designed and implemented by network / data engineers
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 T?
Must establish good practices / parameters in the Recommended Practice!
Dennis P. Ward, University of Michigan
Dennis P. Ward, University of Michigan

3. Networking & Data background an End-User Perspective
Doc.: IEEE /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

4. Doc.: IEEE /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

5. Radio Frequency Test Methods
Doc.: IEEE /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

6. Important RF Test Considerations
Doc.: IEEE /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

7. Conformance vs. Performance
Doc.: IEEE /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

8. Doc.: IEEE /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

9. How can TGT accomplish its goal?
Doc.: IEEE /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

10. What needs to be added to the Recommended Practice?
Doc.: IEEE /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

11. Doc.: IEEE /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

12. First Steps Approve 802.11-04/1540r1
Doc.: IEEE /r0
October 2005
November 2005
First Steps
Approve /1540r1
Generally followed, perhaps a formality
Suggestions to clarify / improve
Document /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