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Not worked with antena specs.

Have seen 3D measurements

my head is spinning like a mixer hahaha. Thanks everybody see you tomorrow.

the anechoic chambers with probes all around looks like a nightmare to calibrate haha...thanks Fanny for a wonderful lecture

Iron

CTIA and 3GPP are the organizations defining MIMO OTA metrics

Blogger

MIMO OTA is a performance metric. FCC is only concerned with regulatory metrics, so they are actually not involved

Blogger

How far are these methods from being adopted by FCC for certification?

Iron

which approach seems more popular in industry?  faders or spatial multiplexing with the use of 2 arms?

Iron

anechoic chamber is the only method for FCC cert today

Blogger

Fanny, which of these approaches, if any, would be applicable to FCC certification of a WiFi device? A Bluetooth device? A cellular device?

Iron

see you soon and good day

 

bye for now :) until next time

Iron

i was thinking for the hp 2 step chamber, you could first test the setup using synchronized correlation test to validate DUT reporting. 

Iron

Thanks Fanny for an excellent program, and thanks everyone for attending. Please join us again tomorrow.

Blogger

we were thinking it might have to do with the conducted setup, but the fact that we saw the same behavior radiated ruled out the conducted setup for us

Iron

is it possible that when you set to 100% power there is nothing inline with the DUT and wen you introdce a slight attenuation you are placing extra programmable attenator circuitry that might introduce a distortion... this may be in instrument artifact... just thinking out loud

Blogger

i cant remember off the top of my head, but it is inline with spec

Iron

and what's the max throughput achievable with 100%?

Blogger

but same behavior is seen in final tis measurement of rssi-based approach

Iron

without fading, we can disable/enable secondary rx antenna through software and run sensitivity through classical TIS

Iron

scilab can also be used it is similar to Matlab,

 

Iron

10% drop per 1 dB step... with fading or without?

Blogger

and then there is Matlab

Blogger

CST Microwave studio is another popular tool for field simulation...

Blogger

fairly often, i see ~10% drop in throughput in 1 dB step size

Iron

The industry likes HFSS for field simulations

Blogger

can we do the field strength db simulation in solidworks?

 

interesting... what is the drop in throughput?  just curious

Blogger

conducted and radiated

Iron

Regarding a sharp drop in throughput between 100% and 95%... is this in a conducted configuration?

Blogger

@MAX-NICHOLE: There should be a correlation of investigation how both methods behaves better, so industry do not aist their capitals!   I know they will not be the smae due to the nature of signal path, and space simulation.

Iron

there are many factors in MIMO throughput and we will dicuss these in the next two lectures - too many moving parts

Blogger

also, in regards to my previous question, do you see the same behavior in your lab as well?

Iron

There may be 3-4 MIMO OTA chambers in the US - just a guess

Blogger

I'm thinking that the differences between anechoic and reverberation chambers are somehow linked to multipath propagation.  If there is a different approach in terms of performances in anechoic chambers and reverberation chambers (some radios are good in one and bad in the other) the base station will be able to see if there is a multipath fading (or delayed copies), therefore will it not be able to signal the device to change its radio (or some parameters.. in the end is a SDR)? (another idea why some are good in reverberation is possible because they are aware of some resonance effect... I don't  know)

ive been using r&s cmw500 to measure lte sensitivity and always see a sharp decline from 100% to < 95% in throughput (usually within a change of <1 dB in dl power). do you know, theoretically, why this happens? i think this also happens using anritsu call boxes...

Iron

How many MIMO test facilities are there in the US?  How many hours to perform a standard series of tests assuming all works well (just rough guess)?

Iron

will do -  I will fix the x-axis label to clarify it - thank you

Blogger

when you update teh slices can you place a label such your answer: The horzontal axis is the power measred in the test zone. ....   MEASURE POWER  FROM THE MIMO. AND yes!!!  if small power is detectable, the Phones are better ...with better sensitivity

Iron

thank you so much! this is really helping for my studies in wireless and mobile communications

Iron

But the two-stage method requires that the DUT itself measures the antenna response... a technique that some test methodology purists are questioning...

Blogger

Two stage method can be used with conventional anechoic chambers that are smaller in size than MIMO OTA chambers.

Blogger

reverb chambers are smaller and less expensive

Blogger

Anechoic is the most expensive method - on the order of 1M USD to erect and high cost every year to maintain

Blogger

was a good course today, hope more of that :)

 

Test zone is also known as 'quiet zone'

Blogger

Is there a rule of thumb for choosing anechoic, reverberation or two-stage?

Iron

The horzontal axis is the power measred in the test zone. There are standard antennas used to calibrate the power in the test zone.  

Blogger

Thanks so much Fanny, Rob, DK and DN.

Iron

OR THE HORIZONTAL  REPRESENT THE POWER APPLIED AT THE MIMO ANTENNAS  WHICH IS NOT EXPLAINED CLEARLY ??

Iron

The FOM plot x-axis is in dBm per 15 kHz.  The lower the -dBm the lower the power.  dBm is an absoulte measure.  Don't confuse dBm with dB  dB is relative.

Blogger

Rob and Fanny, still no audio, followed class with slides and posts, will review with archived file.

Iron

which of the three idealized methods is used more and is there soome preference over selecting it for diferent kind of transmission and anvironment: anechoic, reverberation and two-stage

Iron

AS I UNDERSTAND THESE PLOTS IS BACKWARDS:  MORE NEGATIVE MEANS MORE LOST OF SIGNAL MEASURED AT THE ANTENNA,  SO -92dB is better than - 103dB  but here is backwards ...so i was questioning the meaning of the plotting.

Iron

Very good lecture. Owe way to test wireless routers is with a utility called Jperf

Iron

thank you for a good info

Iron

we developed a Matlab model to synthesize Laplacian cluster field

Blogger

The lower the power reaching the DUT the lower the throughput

Blogger

what kind of simulation did you used for field strength db?

 

This is a lot of material to cover in 40 minutes, but it is a good overview.

Iron

Very interresting, Thank you Rob and Fanny

 

@willyh - The "Bad" phone needs a higher power level for similar throughput.

Iron

willyh, the horizontal axis is signal power. A more negative number is taking lower signal power to reach the same throughput levels.

Iron

Because the Reverberation Chamber has a lot of uncontrolled energy bouncing around, it does not surprise me that the performance appears worse for antenna versus conducted.

Iron

Measure in controlled environment.

Iron

thank you Fanny! Thank's DesignNews!

Iron

Thank you Fanny, Design News and Digi-Key

Gold

CAN YOU EXPLAIN WHY  THE VALUES Of  MORE NEGATIVE GAIN ARE BETTER THAN THE ONE WITH MORE POSITIVE???   WHAT POWER IS MEASURED AT WAHT POINT ???

 

Iron

We're now on slide 35.

Blogger

 

What determines the size of the reverb chamber?

 

Iron

~ok, but will go over again with updated deck

Iron

We're now on slide 34.

Blogger

WHAT IS THE HORIZONTAL  --MEANING????????

 

Iron

I'm not used to reading these plots...not sure I understand the error

We're now on slide 33.

Blogger

We're now on slide 32.

Blogger

If there is an error on the slide, perhaps you can distribute a revised slide set we can download later. I didn't follow exactly what error if any Fanny was describing.

Iron
Makes sense now. I'll download revised slides later to remember it later!
Iron

We're now on sldie 31.

Blogger

don't use licensed bands (including LTE)

Iron

We're now on slide 30.

Blogger

reverbiration chamber in testing

 

We're now on sldie 29.

Blogger

what is the main difference between anechoic and reverbetion chanmber - is it only related to the power averaging?

Iron

Cellular. tested base stations.

Iron

I've used a reverberation chamber in testing.

Iron

We're now on slide 28.

Blogger

Not familiar with reverb chamber.

Iron

I think it's slide 27.

Iron

Yes.  Used base station emulator to test TDMA compliance with Apple iPhone as we were an Apple accessory.

Iron

Familar with reverberation chambers.

Iron
Used Ixia (Veriwave) products for testing some Wi-Fi devices
Iron

never used base station emulator, unlicensed band

Iron

Familiar with reverb chamber in audio

Gold

it is a mixed.  cellular more often

Iron

We use WiFi. Also use cellular - currently GSM, and UMTS. Not working with base stations. Not using LTE yet.

Iron

unlicensed 802.11. never used basestation emulator

Iron

I have never used an emulatro, can you recommend some products?

Iron

fran's? no project at this time, never used base station..

No. I test WiFi products

Iron

Licenced bands. I don't beleive we have ever used a base station emulator.

Iron

We're now on slide 26.

Blogger

Just base station emulator

Iron

Fanny's question:

Do you use licensed cellular bands?  Do you use LTE today?  If yes, what is your frequency band of operation?

Blogger

We're now on slide 25.

Blogger

direction of travel and the speed of the mobile, a dynamic relation?

 

We're now on slide 23.

Blogger

We're now on slide 22.

Blogger

We're now on slide 20 and 21.

 

Blogger

We're now on slide 19.

Blogger

We're now on slide 18.

Blogger

I've done someting close to the setup in slide 17 but for ultrasonic data transmissions for robot orientation

I'm familiar with MIMO OTA standards.  Not involved with MIMO OTA measurements.

Iron

We're now on slide 17.

Blogger

never used MIMO OTA apperatus, looks interesting.

i'm not familiar with mimo ota standards

 

I am not familiar with mimo ota

Iron

I tested throughput vs. device orientation mathmatically to tune gain and amplitude of the main beam.

 
Iron

do not work with MiMO OTA - somewhat new for us

Iron

Not familiar with MIMO standard or measurements

Iron

not familiar with standards

Iron
Not familiar with OTA standard
Iron

no, not familiar with mimo ota standards; nor involved with measurements

Iron

I am not  familiar with MIMO OTA standards

Iron

Yes open air test

not familiar with mimo

Iron

Have not done; not doing MIMO testing right now.

Iron

only for ultrasound transmitter and recevier i made those type of controlling systems

 

Never done any antenna measurement

Iron

not familiar with MIMO OTA standards

Iron

We're now on slide 16.

Blogger

Yes.  We had our own EMI chamber with a rotating table for the UUT.  It was a 3 meter anechoic site used for testing radiated emissions.

Iron

We're now on slide 15.

Blogger

testing usually outsourced

Iron
Have not used OTA metrics
Iron

Have had some training of MIMO standards, just very initial exposure, no experience.

Iron

Fanny's question:

Are you familiar with MIMO OTA standards?  Are you involved with MIMO OTA measurements?  And if yes, what methods have you used?

Blogger

never have tested like this. only experience with traditional radiated EMI measurements.

Iron

Just hand held field tests with no test equipment

Iron

no, never performed any sort of 3D testing...

Iron

My experience is confined to azimuth-only antenna-array calibration.

 

Once I did something similar for a rocket radio test.

Iron

Yes.  360 degree rotation.  Horizontal plane.

Iron

fran's? have done similiar test but not rf.

I have moved around a fixed antenna.

Iron

I have studied antenna specifications in order to use them in designs.

Iron

Yes, former antenna manufacture (HyGain)

Silver

No, i've not 3d testing.

Iron

yes  - specs startpoint for estimation in mine practice

Iron

We're no on slide 14.

Blogger

at my university in Copenhagen

 

Have done 3D testing of antenna in outdoor environment.

Iron

Yes - EMC in testing.

Iron
Have never done that type of testing
Iron

Haven't done it. Looks fun.

Gold

never done 3d measurements

Iron

No in house testing done

 

Iron

Fanny's question:

Have you ever tested throughput vs. device orientation either in open air or in an anechoic chamber?

Blogger

Familiar with plots of antenna specs in 3D. Have taken data for such plots.

Iron

We're now on slide 13.

Blogger

We're now on slides 11 and 12.

Blogger

Yes I have worked with these types of plots.

Iron

No work related to antennas.

Iron

Never studied antenna specs.

Iron

I'm familiar with EMI testing methods

We're now on slide 10.

Blogger

have seen them but not used them

Iron

extreemly limited exposure

Iron

I'm familiar with EMI testing methods.

Iron

yea familiar with 3D antena

 

Standard measurements in open field range
Iron

worked with many specs before but never ant specs

familiar with polar plots in relation to loudspeaker coverage; these appear similar

Iron

I haven't done any work related to antennas.

Iron

fan's? have worked with ant specs.

Have not worked with specs but they seem similar to microphone specs and I'm familiar with those.

Gold

I've seen them before and have a little understanding

Iron

I've only used 2d measurements. I have a basic understanding.

Iron

We're now on slides 7, 8 and 9.

Blogger

I have used 3D antenna measurement

Iron

Have seen them but have not used them.

Iron

Familiar with antenna specs given in 3D plots

Iron

Not used this kind of specs

Iron

Fanny's question:

As part of your work, do you study antenna specification? And do you understand them?

Blogger

no, not familiar with 3d antenna measurements

Iron

I am familiar with 3D antenna measurements and have used them to design antennas.

Iron

Yes, familiar, but hasn't measurement's experience in practice

Iron

I have worked with 3D antenna measurements but it was old school rf.

Iron

Have seen them, have not done them.

Iron

saw anchoic chambers before but never used one

Familiar with 3D measurements for base station antennas.

Iron

No, I have not seem maasurements done quite this way at that frequency.

Iron

I am not intimately familar w 3D

Iron

never needed this elaborate a measurement

 

Iron

familiar with antenna measurements in 3 dimensions.

Iron

I heard about but never done.

Never done measurements or seen measurements

 

Iron

Limited 3-D measurements used

 

Iron

fan's? have seen this done, but long time ago..

Not for mobile devices

Iron

never done 3D measurements

Iron

Seen how is done but not automated

Iron

No 3D measurements.

 

Iron

I have been involved in performing measurements in anechoic chambers.

 

Have not done or seen them done

Gold

No audio, I will keep trying

Iron

Fanny's question:

Are you familiar with 3D antenna measurements?  Have you ever done these or seen them done? 

Blogger

We're now on slide 5.

Blogger

We're now on slide 4.

 

Blogger

why yesterday it was't closed to reality?:-) your models seemed to be very closed :-)

Silly me.  I was waiting on the wrong day.  Good Morning

Iron

We're now on slide 3.

Blogger

Once again, I am unable to get audio on either browser. I was able to attend yesterdays lecture via the archive, and will have to do this one later, too.

Hi all -Audio is live! If you don't see the audio bar at the top of the screen, please refresh your browser. It may take a couple tries. When you see the audio bar, hit the play button. If you experience audio interruptions and are using IE, try using FF or Chrome as your browser. Many people experience issues with IE. Also, make sure your flash player is updated with the current version. Some companies block live audio streams, so if that is the case for your company, the class will be archived on this page immediately following the class and you can listen then. People don't experience any issues with the audio for the archived version.

 

hello from Mishawaka

 

Iron

Are we about to start?

Iron

I keep getting yestereday's slide deck

 

Iron

greetings from Bucharest

Up to 21F in Rochester, NY (started at -4 around 7:00).

 

Iron

hello from eastern Europe

Iron

-The streaming audio player will appear on this web page when the show starts at 2 PM Eastern time today. Note however that some companies block live audio streams. If when the show starts you don't hear any audio, try refreshing your browser. If that doesn't work, try using Firefox or Google Chrome as your browser. Some users experience audio interruptions with IE. If that doesn't work, the class will be archived immediately following our live taping.

Blogger

Good afternoon from Minnetonka.  Sunny and warm 31 today.

Iron

Greetings from NW Montana.  Getting our first good snow of the winter. It's coming straight down real pretty.

Gold

hi you guys from SoCal

Iron

Looking forward for another great lecture from Fanny.

Iron

Q: Fanny, do you know of a good source or sources of information about health risks (e.g., brain tumour) associated with cellular phone usage (in particular, phone against skull, cf. "the sphere around the DUT") ?

David Servan-Schreiber, M.D., PhD (neurology) discusses this topic in the DVD production of his book "Anticancer", and mentions, if I recall correctly, that while few long-term studies exist to date the danger is certainly real.

Iron

How's everyone doing? I hope everyone is alright even though its very cold brrrrrrrrrrrrrrr

Iron

Good afternoon from Summerville, SC

Iron

Hey from Tucson, AZ! It's going to be around 80 degrees (F) today. 

Iron

still waiting for the perfect course about MIMO over the air, hope to find our the necessary things in my mind :)

-You are eligible to earn IEEE Professional Development Hours by attending these courses and participating in the chat function. Additionally, we are no longer using the points system, offering "graduation", or giving grades. The IEEE hours are taking the place of that. There are some important things for you to know about earning the hours. The most important ones are that you need to attend these courses live, you need to attend a minimum of two of them per semester, you need to fill out a course evaluation form within 2 weeks of the end of the class, you need to attend 4 out of the 5 classes per course, and you need to participate in the chat function every day you attend. Please click on the link at the top of this page that says "How do I earn IEEE professional development hours" to read all of these important details and more.

Blogger

Hello from Somewhere on the Niagara Frontier

Iron

Good night from Valladolid, Spain

Iron

-Be sure to click 'Today's Slide Deck' under Special Educational Materials above right to download the PowerPoint for today's session.

Blogger

Hello from El Paso, TX

Iron

Hello from Yemen we are waiting to your event

Iron

Hello from Hudsons Hope BC

Iron

a wonderful class today, MIMO

-Be sure to follow @designnews and @DigiKeyCEC on Twitter for the latest class information. We encourage you to tweet about today's class using #DigiKeyCEC.

Blogger

Good morning from Icy Panama City, FL.

Iron

Hello, From Salt Lake City, Utah

Iron

Good morning from Albuquerque, New Mexico

Blogger

-Please join our Digi-Key Continuing Education Center LinkedIn Group at http://linkd.in/yoNGeY

Blogger


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