1. MIMO performance Test Methodology proposal
doc.: IEEE /0742r0
May 2006
MIMO performance Test Methodology proposal
Date: May, 2006
Authors:
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Lemberger Uriel, Intel
Lemberger Uriel, Intel

2. doc.: IEEE /0742r0
May 2006
Abstract
This document introduces a simplified and basic concept for testing Throughput of MIMO system.
It describes measurement methodology and metric for TPT performance testing of n wireless LAN devices.
Lemberger Uriel, Intel
Lemberger Uriel, Intel

3. Agenda Purpose Setup Traffic use cases Measurement procedure Summary
doc.: IEEE /0742r0
May 2006
Agenda
Purpose
Setup
Traffic use cases
Measurement procedure
Summary
Lemberger Uriel, Intel
Lemberger Uriel, Intel

4. doc.: IEEE /0742r0
May 2006
Purpose
This test is a simple baseline example of WiFi TPT test for .11n WiFi devices.
There are two levels of complexity of the test setup:
Using net of attenuators and fixed phase shifters.
Using complex channel simulator.
This test is applicable to an infrastructure BSS as well as to IBSS.
Lemberger Uriel, Intel
Lemberger Uriel, Intel

5. Test Setup - Conductive
May 2006
Test Setup - Conductive
This test can be carried in 3 types of environments:
Conducted setup:
In analogy to the conductive setup described in [1] section 5.3 we use similar setup with a bank of mxn attenuators instead of one in the above.
Schematic diagram for 3x3 system described in fig 1.
Lemberger Uriel, Intel

6. May 2006
Conductive environment Measurement setup Generic Test Setup (up to 3x3 solution) for MiMO conducted Performance Tests
Lemberger Uriel, Intel

7. May 2006
Test Setup - Chamber
Two setups may apply for this measurement as described below:
Chambered setup:
In analogy to the chamber setup described in [1] section 5.2 we use similar setup with a bank of m attenuators in serial with the antennas of the WLCP instead of one in the above.
Schematic diagram for 3x3 system described in fig 2.
Lemberger Uriel, Intel

8. May 2006
Chamber environment Measurement setup Controlled OTA test inside a screen room – Test setup proposal
Lemberger Uriel, Intel

9. Test Setup - OTA OTA setup:
May 2006
Test Setup - OTA
OTA setup:
OTA setup is similar to the setup described in [1] sections
Test equipment should be capable to handle the higher data rates involved in 11n devices testing.
Lemberger Uriel, Intel

10. Calibration and precision requirements
doc.: IEEE /0742r0
May 2006
Calibration and precision requirements
Calibration of the attenuators and the phase shift contributed by the connecting lines between the antennae is critical for the accuracy of the measurement.
Each link between 2 antennae should be measured and calibrated per channel.
Lemberger Uriel, Intel
Lemberger Uriel, Intel

11. The test cases will include:
May 2006
Proposed Test cases
The test cases will include:
Ideal multi-stream network
Orthogonal streams
Non ideal reception with correlation between streams
Lemberger Uriel, Intel

12. Measurement Procedure
May 2006
Measurement Procedure
The measurement procedure is similar to the existing SISO testing with additional paths to control.
The test procedures emulate major use cases.
Simulating N ideal links –
Hii are running simultaneously from (min to max) attenuation in 1dB steps (can be a larger step as well)
Hij are set to maximum attenuation.
Simulating N orthogonal links–
Hij=Hii-6dB 0deg,(j=i+1) Hik=Hii-6dB 180deg (k=i+2)
Lemberger Uriel, Intel

13. Measurement Procedure Test Description – Proposed Test cases
May 2006
Measurement Procedure Test Description – Proposed Test cases
Simulating each Tx antenna received by each Rx antenna (3 ideal signals and other signals are attenuated) –
Hii are running simultaneously from (min to max) attenuation in 1dB steps (can be a larger step as well)
Hij=Hii+ fixed offset of [6,12,18] dB
Simulating a use case where there is a Rx signal power delta between all of the signals received –
For example in 3x3 use case – H33=H22+6dB=H11+10dB ; Hij=Hii + (-1)^(i)*( 6dB),
running from (min to max) attenuation in 1dB step.
Simulating Pure MRC (Maximum Ratio Combining) mode –
H11 is running from (min to max) attenuation in 1dB step.
H12=H11+ fixed offset in each attenuation of [0,6,12] dB
Changing "lanes" - exact steps for each "lane" will be decided by trial and error Simulates OTA real environment where rapid changes occur (Similar concept to the conductive Diversity test in legacy mode),
Lemberger Uriel, Intel

14. “Changing lanes” Test example
May 2006
“Changing lanes” Test example
A11=A21+4 =A31+ 8
A22=A12+4 =A32+ 8
A33=A13+4 =A23+ 8
50dB
20dB
-5dB
+5dB
Lemberger Uriel, Intel

15. Summary The 11n MIMO TPT test has been proposed The proposal contains:
doc.: IEEE /0742r0
May 2006
Summary
The 11n MIMO TPT test has been proposed
The proposal contains:
Purpose of the measurement
Descriptions of test setup modifications
Baseline channels, modifiers channels
Calibration and precision requirements
Description of test cases
Measurement Procedures
Recommendation:
Adopt this concept as a baseline for MIMO testing proposal
References: [1] IEEE TGT draft D0.7
Lemberger Uriel, Intel
Lemberger Uriel, Intel

16. May 2006
Straw polls
Does the TGT in favor of having 11n devices testing in TGT draft?
Y/N
Does the TGT in favor of having this concept of measurement and metric for MIMO tests in TGT draft?
Lemberger Uriel, Intel