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what is the tool you used to collect the drive test results?

Iron

Have not worked with though have studied it.

Iron

Have not worked with mimo

Iron

No phase arrays or beamforming

No current work with frequencies / bands. Learning ...

No experience with MIMO technology

Thank you and have a great day.

Iron

Thanks everyone for attending. Please join us for tomorrow's session.

Blogger

One thing about the modulation schemes. A great way to see the QAM and QPSK modulation schemes is to look at the "constellation" of the signal. This is a sort of rectangular plot that shows all the possible symbol values.

Iron

Question: Do you know of any/can you recommend some sort of simulat[or][ion] (non-HW; just for illustration) that might help develop an intuitive sense of how these various modulation schemes (/beam manipulation/etc) work? I know there are modeling packages that can probably be used for that, but, let's say I don't need that functionality (at the moment, anyway).

Iron

regarding different antenna types, there is a lot of creative work happening, particularly to enable lower correlation in small handsets and any technique is considered. polarization is one way to enable 2 streams in a small space - you need low XPR (cross polarization ratio)

Blogger

I'm glad you appreciate the technical challenge, dzeez

Blogger

I agree with @dzeez.  Technical Detail is excellent.  Thank you.

Iron

Another question, is it viable to use say one antenna type, like PIFA, or printed dipole, etc, in multiple positions in a MIMO system? And must we use different polarizations in the array? Can we use only one polarization type and be successful?

Iron

For future generations beyond OFDM, we may go to more sophisticated OFDMA and multi use MIMO. These technologies are in their nascent form today and have a long way to go.

Blogger

Thank you -- though I, clearly, have much to go over and dig deeper into before I can be close to "owning" this material, I did appreciate the technical level of this presentation in particular. (I understand that giving us the entire context of radio comm was necessary; and likewise, I appreciate that you didn't leave anything out there, even if it was a now-waning spec.)

Iron

regarding antenna separation, that's correct - they are typically separated by a multiple of wavelengths; higher frequencies require less separation for the same correlation and that works in favor of higher MIMO capacity.

Blogger

Question: it seems that 802.11 and LTE standards are settled with OFDM modulation. In your opinion, would there be a need for a new modulation scheme for even higher throughput requirements and what that modulation scheme would likely be?

Alaskaman also had a good question, that I'll add to: How do we select a separation of transmit antennae, or receive antennae, in MIMO systems? Spacing is related to wavelengths? How do we consider wavelength when the BWs are becoming wider?

Iron

Re beamforming vs. wide angular spread... a narrow beam can still bounce around and have a wide angular spread

Blogger

number of bits per symbol depends on modulation; e.g. QPSK gives us 2 bits per symbol

Blogger

How to solve the conflict between doing beamforming (this reduces angular spread) and having a wide angular spread to increase throughput?

Iron

Question from Goerge Mallard:

How many bits in a symbol?

Blogger

re slide 19 comment - yes - high power is allowed but path loss is very high in the 60 GHz band so you need all the power you can get.  For all practical purposes CMOS power amps cannot get that much power out today.

Blogger

Great lecture. Very complex subject

Question from CPU:

Fanny, question, slide 19: 57dBm EIRP ... that's such a high effective power, 500W! The actual signal path is using lower power fed to very directional antennas with lots of gain?

Blogger

Thank Fanny very complex good thing it can be hinden from the end user.

Iron

CurtisTech, this is the live Q&A.

 

Blogger

Thank you- good detail.

 

Iron

Very good presentation, thank you

How do you get to the live Q&A ?
Iron

thanks for the answers.

Thank you Fanny, Rob. and Digi-Key

Gold

number of bits per symbol depend on modulation order (e.g. QPSK, QAM16, etc.)

Blogger

Excellent tech presentation, Fanny! and thanks.

Iron

Thank you. I now appreciate how complex the testing is going to be to keep all the parameters controlled. Looking forward to tomorrow.

Iron

Thank you, very good lecture...

Iron

MIMO is so interesting. Thanks Fanny and Digikey.

Iron

Thanks Fannie, be here tomorrow

Iron

Thanks Fanny and Rob.  Need a cheatsheet for acronyms.

Iron

Thanks Fanny, Rob & Digi-Key

Iron

Thank you Fanny. Great lectures.

Again, a great lecture!

Iron

Thanks for the lecture Fanny!

 

Iron

Thanks for the good info.

Iron

How many bits in a symbol>

 

We're now on slide 25.

Blogger

QAM is Quadrature Amplitude Modulation.

 

Use circuits, or math transforms, to obtain 90 deg shifted signal.

Iron

Quadrature Amplitude Moulation

QAM = Quadrature Amplitude Modulation. Signals used in modulation are in "quadrature", i.e. 90 deg phase shift.

Iron

We're now on slide 24.

Blogger

Can someone tell me what QAM is?

Gold

We're now on slide 23,

Blogger

Fanny, question, slide 19: 57dBm EIRP ... that's such a high effective power, 500W! The actual signal path is using lower power fed to very directional antennas with lots of gain?

Iron

We're now on slide 21.

Blogger

We're now on sldie 20.

Blogger

Question: slide 19; dBr debrinco?

No.  I have not used any 11ac technology to my knowledge, and I have not done any testing with it.

Iron

have not used .11ac technology

Iron

We're now on slide 19.

Blogger

Fanny's question:

Has anyone in the group used or tested 11ac technology and how do you find it?

Blogger

We're now on slide 18.

Blogger

We're now on slide 17.

Blogger

Not yet unfortunately; I do find beamforming/arrays/other wavefront manipulation very interesting

Iron

We're now on slide 16.

Blogger

I built Yagi antennas a few times.

Iron

We're now on slide 15.

Blogger

For moving receivers in a beam forming system, is there an upper limit for receiver velocity before the transmitter can't follow with beam aiming?

Ditto, Ham Radio use...

Iron

Just in  ham radio use. 2 & 4 antennas.

Iron

Not using beam forming yet.

Iron

Just studied phased arrays.

Iron

I worked with a military contractor on a focal plane array.

Iron

Yes, beamforming.  Latest with only 4 sensors.

used beamforming a lot in HAM radio, using 4 antennas

Iron

no beamforming or phased array work

Iron

128 QAM = 7 bits/symbol I think so. 2^7 = 128

Commercial beamforming - 8 antennas @ 2.5-2.7 GHz

Iron

come on, there's kids on here!!!!

Iron

No experience with phased arrays

Fanny's question:

Anyone from the military here who has worked with phased arrays and beamforming?  Anyone who is working with beamforming commercially?  How many antennas are you working with?

Blogger

We're now on slide 14.

Blogger

For MIMO to work, how many wavelengths do the receivers need to be separated by?

We're now on slide 13.

Blogger

We're now on slide 12.

Blogger

Almost 20 years ago I worked in PSK and QPSK long time. Sorry.

Iron

We're now on slide 11.

Blogger

Almost 20 years I worked in PSK and QPSK long time.

Iron

128 QAM = 7 bits/symbol?

We're now on slide 10.

Blogger

lived with a TDMA cell phone for some years...thus, learned how it worked (to some level)

Iron

aware of concepts but never worked.

Iron

We're now on slide 9.

Blogger

Have used satellite links using TDM methods to modulate channel data on an on-the-fly basis

I have worked with TDMA and OFDMA.

 

 

frequency division mult.

Iron

have worked with both time and freq div multiplexing in Sat data comms

Iron

No OFDMA experience.

Iron

aware of concepts but never worked with directly

Iron

We're now on slide 8.

Blogger

Fanny's question:

Have you worked with time-division, frequency division multiplexing technologies or contention based technologies?

Blogger

Question: slide 7; Is the frequency allocation the same as spread spectrum?

We're now on slide 7.

Blogger

Not designing any interfaces at the moment, but have used 2.4 GHz interfaces previously.

Iron

We're now on slide 6.

Blogger

2.4GHz (+some lower ISM bands)

Iron

Question: slide 4; Is this technique similar to space diversity in microwave transmission?

We're now on slide 5.

Blogger

Working in 800-900, "AMPS" band, PCS band, ISM.

Iron

430, 915, 1.8G, 2.1G, 2.4g

Iron

2.4GHz ISM, potential for slightly lower.  Legacy much lower than that.

Iron

Used 900 Mhz in the past for longer range

Iron

700MHz, AWS, 1.8 GHz, 2.6 GHz

NOt at this time, but interested

Iron

We're now on slide 4.

Blogger

Fanny's question:

If you are designing radio interface, what frequency band are you working in?

Blogger

not directly with mimo

Iron

Receive diversity only so far, so not real MIMO yet.  Coming quickly though.

Iron

Never worked with any of this, except as a consumer. 

Yes, WiMax and proprietary

Iron

Have not worked with MIMO

We're now on slide 3.

Blogger

Fanny's question:

Have you worked with MIMO technology and if yes – which technology?

Blogger

We're now on slide 1.

Blogger

Good evening from HB, D

Iron

Greetings from West Point, PA, USA.

Iron

Good afternoon, everyone

Iron

How're you guys?

 

 

Iron

hello from Mishawaka

Iron

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.

Hi from nighttime Copenhagen, Denmark

Iron

Greetings from oarfish central, San Diego

Iron

Present and ready.  Greetings from San Jose, CA

Iron

Greetings from Vermont

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

First partial frost here too, in PA

Iron

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

Blogger

Albuquerque was very nice, saw the balloons last week.

Good morning from Valdez. First frost of the year.

I am looking forward for another great lecture.

Iron

Greetings from Summerville, SC. How is everyone doing? How are you Fanny and Rob.

Iron

Hello from Huntsville, Al.  Fall weather is upon us.

Iron

Greetings from Raleigh NC

Iron

Heloo from cold Lake Simcoe Ontario

Iron

rruther2, I'll bet Fanny wasn't finished editing her slides last night and that's why you saw the duplicates.

Blogger

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

Blogger

Morning, now 25 good slides

Iron

Hello from Albuquerque.

Blogger

I don't see in duplicates in the slidedeck I downloaded. Plus, there are only 25 slides. So perhaps rruther2's slidedeck goofed up during its download.

Blogger

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

Blogger

Morning from Portland Oregon

Iron

Slide 20 & 21 identical as are 32 & 24 of the 27 slides present.

Iron

Somewhwew in research engineering it stated she was born and raised in Philadelphia PA.

Business and schooling in Boston, MA

Iron

Where does Ms. Minarsky hail from ?



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