How space-time codes work (5G networks)

Information Theory Society presents a brief history of wireless communication (radio) leading to the idea of multiple-antenna wireless systems (MIMO) and space-time codes. 5G networks
Written by:
Brit Cruise
Matthieu Bloch
Michelle Effros (corrected from video)
Suhas Diggavi (corrected from video)

[@nyscersul42]

I love how you showed the alternating current on the battery... perfect illustration hehe

[@3nthamornin]

i just found your channel by accident and ive got to say your content is FANTASTIC! you explain the concepts so well. thanks!

[@ArtOfTheProblem]

Cool glad you found it via this video, stay tuned!

[@samirkaushik8863]

Thanks for the amazingly simple explanation!

[@ArtOfTheProblem]

cool nobody has found this video a in a while

[@jameswise9171]

This is the best KZbin channel.

[@ArtOfTheProblem]

Thank you for your kind words - stay tuned for more

[@JavierSalcedoC]

Art of the Explanation

[@zeikjt]

That was great. I love how simple the solution was, that's an inspiring engineering result :)

[@yomanos]

Keep up the good work, this channel makes great content.

[@desert-rat145]

Very good explanation! I'm working on my CCNA wireless cert and I hope to see more wireless related videos

[@mehaksaini2552]

Such awesome content!!! Wow!!

[@endxofxeternity]

I love this!

[@ArtOfTheProblem]

glad you found it, was fun to make

[@ZonkoKongo]

I love all 11:31 minutes of this video.

[@Superogobongo]

Truly excellent presentation, thank you

[@prasidhr5130]

At 11:15, the background looks like the walk area at NUI, Maynooth in the southern campus. The multiple transceivers setup at 11:03 looks like one in TCD. Are you Irish?

[@betoib1504]

That was awesome, thank you!

[@ImmacHn]

I love this channel.

[@pscheidt]

Really good! Sharing like crazy.

[@ArtOfTheProblem]

much appreciated

[@johnaweiss]

Is "A" a carrier frequency? A simple fixed-frequency, fixed-amplitude modulation of the carrier? Multi-quadrant data?

[@SerioSeria]

This is just gold! You are producing extremely high quality material for free to educate people on Information Theory. You really have the gift to turn complex concepts into digestable and meaningful information that most people in this field can get. That is just brilliant! I am teaching this myself and find it hard to explain in a simple, easy to follow manner. Your videos help me a lot with improving the teachability of this concepts. Thanks a million for all of your content! Keep up the awesome work!

[@ArtOfTheProblem]

thank you so much for the words of inspiration

[@zga8]

Very good explanation

[@grjesus9979]

The whole thing about MIMO is to increase capacity. Due to multipath there is going to be inevitable different delays associated with different paths. Therefore when a transmitter sends a symbol in different antennas, in the receiver it just dont arrive at the same time. So my question is what is the whole point of MIMO if we dont take into account the delays and therefore the whole impulse response associated with each path. In other words why you only consider fadind as a scalar factor? Shouldnt it contains also a delay factor?

[@grosugeorge2107]

I find this a good point and the question is nice. I think the phase shift is assumed somewhat sufficient to incorporate delay as an out-of-synchrony measure, although in my humble opinion its far from being the same as phase shifts are shift-direction invariant (they alone dont tell you necessarily if one signal is behind or more advanced than the others signals). Definitely there is more to cover on this topic.

[@shaaradayamini]

The delay spread is taken into account in OFDM-MIMO systems, the symbol time in OFDM systems is sufficiently higher than the delay spread at the receiver antennas. It means that the duration for which a 1 or 0 is being transmitted is large enough, that the smaller delay spread does not let them interfere and the Receiver can separate them out.

[@muhammadadil3981]

Sir, can we ask for videos to be prepaired on request? On suggested topics?

[@ArtOfTheProblem]

No I don't take solicitation but I always open to suggestions. unless you'd like to commission a video?

[@muhammadadil3981]

@@ArtOfTheProblem Videos related to Information Theory? Like for example on "Shannon Channel Capacity Theorems" etc.

[@ArtOfTheProblem]

@@muhammadadil3981 i have a whole series on this! check out my channel page (episode 2)

[@muhammadadil3981]

@@ArtOfTheProblem sure sir

[@xramoj]

1st MIMO video that gives a little bit of explanation.

[@ArtOfTheProblem]

that was the goal

[@NeelBasu]

In the cellphone example there are multiple transmitting antennas and a single receiving antenna. So it is multi input. But I don't understand why that is multiple output ? Because the cellphones do not have multiple antennas. Why it isn't Multi Input Single Output ? Or do the cellphones have multiple antennas too ?

[@ArtOfTheProblem]

That's correct the cell phones also have multi antennas.

[@NeelBasu]

@@ArtOfTheProblem yes, but one antenna for gsm another antenna for cellular another antenna for bluetooth another antenna for gps ? What if a device only have a cellular communication abilities no wifi, gps, bluetooth. Or if a device have wifi only, no cellular, gps, or bluetooth. Does the device still have multiple antenna ?

[@cryptomania3553]

Gold

[@CrucialMuzic]

Another video from Art of the Problem!!? Someone pinch me, I must be dreaming ;p Again very informative and straight to the point, I love it :)

[@ArtOfTheProblem]

stay tuned for more, appreciate it

[@inarisound]

Astonishing.

[@adityasahu96]

omg what an explanation!!

[@gabepk]

Wow! I graduated from Computer Science 2 years ago and I had no idea about this. I have one question, though: Do you know if phones that accepts 2 SIM cards have 2 signal receptors? Because sometimes one SIM can be out of service, but not the other one. :)

[@mycontent3632]

9:00 How does the receiver know what H_1 and H_2 are? Doesn't it need that to find A and B?

[@prateeksingh5293]

I don't think that the receiver needs to know H_1 and H_2 because the decoding algorithm for the message remains the same The two message symbols being sent remains in the form of (A)(B) and (-B)(A). Now, regardless of the receiver knowing whether the symbols are being sent from H_1 or H_2, the received equations will remain A-B and A+B

[@__-xl1zi]

*PLS KEEP MAKING VIDS!*

[@ArtOfTheProblem]

new videos on the way

[@__-xl1zi]

Thx man! I was so scared cause this was posted months ago and I thought for a second u stopped! R u ever making one for how cryptocurrency works? I saw you made a teaser for it before. I rlly was looking forward to it.

[@ArtOfTheProblem]

yes I have a 30min special video on Bitcoin coming out in < 1 month, been working on it for a long time.

[@daslolo]

wow! so clear

[@ArtOfTheProblem]

glad to hear it thanks for the feedback we have 3 more of these on the way

[@daslolo]

Very nice I'll watch them! Could you have a look at the DJI Digital FPV and tell me what you think of the antenna configuration? We usually fly analog and so we don't really deal with this distribution of signal, deciding on antennas is trivial but with a MIMO... no idea what's the best configuration for long range, probably not something as trivial. Also did you read that paper by a Chinese team where they use circularly polarized antennas to increase diversity?

[@abdurrahmansa3763]

Awesome

[@Primence]

niced

[@KittyBoom360]

If you could explain entropic uncertainty in reference to information theory and quantum mechanics in a comprehensive way to your viewers... Wait, what I am asking, the impossible??? Are you up for it? (but don't let anything delay your upcoming stuff on Bitcoin and blockchain!)

[@ArtOfTheProblem]

:) We do plan to cover Quantum Information Theory in 2018

[@kumu141]

11:23 it is supposed to be Suhas Diggavi (UCLA)

[@diego898]

The music was very high-tension - something out of There Will Be Blood

[@anujmandrekar171]

the background music is very irritating

[@__mk_km__]

Naaah Just gonna use PRN codes ;)

[@chuckjordan6455]

1:18 "BY THE 1980s"? Why by the 1980s??? That doesn't make sense.

[@SuperSeagull12]

1:41 That's... not how a signal generator works.

[@Killadog1980]

It is so obvious that you should have asked yourself, why would he represent the signal generator like that?

[@SuperSeagull12]

@@Killadog1980 I think you missed my point. Showing a signal generator as a box with wires mechanically dancing around inside is quite silly.