1. doc.: IEEE 802.11-05/0451r0 Submission May 2005 Kobayashi, Trachewsky, Victor, Broadcom CorpSlide 1 Cairns: Proposed Over the Air Test Methodology Draft Text 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: 2005-05-17 Authors:

2. doc.: IEEE 802.11-05/0451r0 Submission May 2005 Kobayashi, Trachewsky, Victor, Broadcom CorpSlide 2 Abstract This presentation is in support of draft text in 802.11-05/0450r0 based on previous presentations on Controlled Open Air Test (COAT) Methodology. This presentation is being presented following 11-04-1553-r2, “Guidelines for TGT Formal Metric and Methodology Proposals”. The draft text for the recommended practice follows the approved template as outlined in 802.11-05/1641r01, “Metrics Template Example” Presentations made to TGT in the past are: 802.11-04/1476r0, “A Proposed Open Air Test Methodology” 802.11-05/0235r1, “Proposed Over Air Test Methodology Update” 802.11-05/1622r0, “Update to Proposed Open Air Test Methodology”

3. doc.: IEEE 802.11-05/0451r0 Submission May 2005 Kobayashi, Trachewsky, Victor, Broadcom CorpSlide 3 Agenda TGT Objective TGT Background Goals Methodology Example Block Diagram of setup Precision Recommendations

4. doc.: IEEE 802.11-05/0451r0 Submission May 2005 Kobayashi, Trachewsky, Victor, Broadcom CorpSlide 4 Objective From PAR and 5 criteria: –Scope: The scope of 802.11T is to provide a set of performance metrics, measurement methodologies, and test conditions to enable measuring and predicting the performance of 802.11 WLAN devices and networks at the component and application level. –Purpose: The purpose of 802.11T is to enable testing, comparison, and deployment planning of 802.11 WLAN devices based on a common and accepted set of performance metrics, measurement methodologies and test conditions.

5. doc.: IEEE 802.11-05/0451r0 Submission May 2005 Kobayashi, Trachewsky, Victor, Broadcom CorpSlide 5 Background The objective of TGT is to come up with a repeatable measurement methodology and to provide –set of metrics –measurement methodologies –test conditions to enable measuring and predicting

6. doc.: IEEE 802.11-05/0451r0 Submission May 2005 Kobayashi, Trachewsky, Victor, Broadcom CorpSlide 6 Goals Propose a controlled open air test (COAT) methodology to help achieve the goals and objective of TGT –Allows for complete system evaluation including antenna and effects of all components of SUT –Allows for repeatable tests which yield precise results. –Covers, in overview form, the proposed draft text for the TGT recommended practice

7. doc.: IEEE 802.11-05/0451r0 Submission May 2005 Kobayashi, Trachewsky, Victor, Broadcom CorpSlide 7 Methodology Overview Utilize setup that severely reduces any interference from outside sources –Screen room –Use a directional antenna and RF absorbent material to reduce multipath effects Take a channel measurement of the Open Air with SUT removed and characterized antenna in exactly the same position and orientation as where SUT antenna would be in free space Utilize calibrated path loss to determine amount of received power as seen by the SUT –Measure transmitted power out to cabled portion add additional path loss to determine rx channel power level Place DUT in place such that RX antenna is exactly in the location and orientation that was calibrated by step above Run desired test using calibrated path loss Include measured channel characteristics with reported results

8. doc.: IEEE 802.11-05/0451r0 Submission May 2005 Kobayashi, Trachewsky, Victor, Broadcom CorpSlide 8 Overview of Controlled Open Air Test Open air channel can be broken into two components –The open air channel by itself –The DUT platform channel Create an environment where open air channel is virtually flat – reduce multipath channel response REF Open Air Channel DUT DUT platform channel System Under Test (SUT) * = REF Open Air Channel DUT DUT platform channel System Under Test (SUT) * =

9. doc.: IEEE 802.11-05/0451r0 Submission May 2005 Kobayashi, Trachewsky, Victor, Broadcom CorpSlide 9 Example Block Diagram Open Air Calibration AMP Network Analyzer Main beam pattern of tx antenna pointed toward open end of RF enclosure to minimize multi-path channel effects –Keeps channel frequency response flat –Directional antenna focuses the majority of energy in a particular direction Rx antenna is in the far field of the tx antenna Amplifier puts received signal within rx sensitivity of network analyzer Collect channel response to determine calibration Inner Walls lined with RF absorbent material RF shielded screenroom calibrated antenna directional antenna

10. doc.: IEEE 802.11-05/0451r0 Submission May 2005 Kobayashi, Trachewsky, Victor, Broadcom CorpSlide 10 Example Block Diagram Open Air Test REF Variable Attenuator DUT Use power meter to measure tx power Variable attenuator creates additional path loss for determining path loss sensitivity Power meter directional coupler Inner Walls lined with RF absorbent material RF shielded screenroom directional antenna

11. doc.: IEEE 802.11-05/0451r0 Submission May 2005 Kobayashi, Trachewsky, Victor, Broadcom CorpSlide 11 Precision Requires a very accurate positioning and orientation system. Requires knowledge of the exact location of the antenna(s) in the DUT (sometimes enclosed in the chassis) Open air calibration measurements, requires precise placement (x,y,z) of the calibrated antenna and the actual SUT antenna. –Location of the RX calibrated antenna is key to a good measurement –Note the RX calibrated antenna can be a simple dipole as long as it is well characterized. There is no need for a high-gain antenna like that used in the TX reference Items utilized during all measurements need to be placed precisely in the same locations in all measurements –TX directional antenna needs to be in same location

12. doc.: IEEE 802.11-05/0451r0 Submission May 2005 Kobayashi, Trachewsky, Victor, Broadcom CorpSlide 12 Using Lasers for Position and Orientation Diagram illustrates the use of lasers to precisely place the DUT antenna in the same spatial location and orientation as where the calibrated antenna was

13. doc.: IEEE 802.11-05/0451r0 Submission May 2005 Kobayashi, Trachewsky, Victor, Broadcom CorpSlide 13 Recommendation TGT should accept the draft recommended text included in 802.11-05/0450r0 Controlled Open Air Test Methodology for doing full system characterization –Results will be more precise and repeatable than uncontrolled open air tests –Results will reflect system effects which cannot be simulated or measured in purely conducted test environments