Digital Communications: Viterbi Algorithm

Graduate Student Zac Sutton of Uconn HKN explains how to encode a data stream using a convolutional encoder and how to decode the received sequence using the Viterbi Algorithm.
Still don't get it? Have questions relating to this topic or others? Suggestions for other problems you'd like to see us do? Post in the comments below or email us at "[e-mail]

[@wokwithjosh1473]

Not only is the explanation clear, the way the tables or chart are layout is systematic. I will use this approach for my exams

[@BS-jw7nf]

My savior. Explained in 4 hours worth of lecture in 26 minutes and way clearer

[@negarm4483]

Every time I need to review the viterbi algorithm, I watch this video. Thanks a lot for this clear explanation.

[@rohitvasu]

man !!! thank you !!! this question saved me 20 points in the finals !!! thank you so much for this explanation !!

[@ferhatvarolgunes8630]

man this is most clear explanation that i saw too far thanks for making it so simple, appreciated man thanks a lot.

[@nyanjomjackonyango2902]

Thanks alot for this. Simple to understand and straight to the point.

[@a7mad00iraq]

Thank you very much man, you really made it look so easy.

[@jshiva3]

Thanks a lot for the patient and beautiful explanation

[@lucasgameiroborges6086]

best explanation ive seen, keep up the good work!

[@space_0027]

Thanks so much!! Makes a lot of sense now!

[@carloseduardomayerdeolivei2913]

Thank You! Nice and clear explantion!

[@amirnazari6427]

Thank you, great and clear explanation.

[@johnli2026]

Exellent! the best I have seen on this topic!

[@JohnDoe-sm9ww]

Clear and concise. It's been quite useful! Thanks and congratulations!

[@WistrelChianti]

Thanks very much, really clear explanation and I appreciate you saw the process through fully (satisfying for the learner and the extra practice is no bad thing). Any idea what a multi convolutional encoder is? Applying a convolutional encoder more than once? (i.e. encoding the output of the original encoding) or something else?

[@Clo326]

thank u so much... love it.. good explanation...

[@SuperJosba]

Great tutorial, thank you!

[@juandeaton5692]

Well done thanks for posting!

[@PETAJOULE543]

Nice demonstration of viterbi algorithm which is used in convolutional decoding.

[@liastheodoreskordas3793]

Thank you very much. Very good teacher.

[@jdnfirst240]

Yeah, it was very much useful. Thanks a lot.

[@archer_mkii]

Thanks a lot , this was helpful

[@saintgersh]

Excellent explanations. Why didn't I see this video before my exam??

[@mussie2040]

thank you professor

[@smiley5867]

superb! and elegant!

[@nightingale3712]

didn't attend to classes (i'm lazy i know), so you saved me.. thanks C:

[@sameerasandeepa1571]

Thanks . That was so helpful

[@vasanthsathyanarayanan2376]

great... thanks for helping out

[@sofiaasmi8923]

you saved my exam!!

[@NguyenNguyen-ju5ur]

me too?

[@klodious9778]

the question is, probably the stream length is unknown so when we implement the viterbi algorithm do we implement the digital design when we reach a certain size so only then it returns the best path with the least hamming distance or not? and if so how could I determine the appropriate ram size.

[@danhhuyvu2336]

Thanks so much !

[@agostinhomaia9025]

Awesome!

[@t.chumpuwiset5945]

excuse me sir, can you show me in case that considering 2D 3x3 matrix? they call it 64 state but i think it should be 512 state for that (8x8x8)

[@Anuparamkarad]

Simply explained

[@stefm.w.3640]

You're a god. Thanks all the way from Europe btw

[@mehdiAbderezai]

I wish you were teaching our class

[@nereaortiz4144]

Thanks!!

[@hichamtribak1944]

love your work. great explanation. Good continuation professor. The initial code word is 00110, so what is the first input bit to be injected into the encoder, if we want to do reverse encoding? i.e from 00110 to the corresponding encoded message. is it the far right 0 or the far left 0?

[@UConnHKN]

If I am understanding your question you are asking what happens if you want to feed bits in reverse? Then you would start with the most significant bit, instead of the least significant bit in the ``word''
~Andrew.

[@hichamtribak1944]

Thank you very much Professor. Good continuation.

[@sanjeevn2467]

this so helpful

[@arbrakraja9825]

thank you

[@Marta97df]

Amazing!

[@ashishgurung5223]

what for the sequence "100110101" using trelli diagram

[@hosseinbeiranvand7169]

very good and beneficial

[@NicoFenane]

The Viterbi algorithm adding two bits to the end of the word, for back to the initial state. Knowledge this, the path is generated by 01000, where the last two bits (00) are redundant.

[@apostlej2015]

Nice job

[@KarpmasterWayne]

Life saver.

[@navidarshadi8074]

perfect

[@toannguyenkhanh3299]

thanks

[@AhmedSaid-ql6hd]

god bless you

[@paynicole6432]

awesome

[@crazydrifter13]

What trickery is this?

[@thomasrock6722]

I think the binary values for 10 and 01 are the wrong way around on the left side of the trellis diagram

[@akilkarthikeyan]

Yep, the output values for 10 alone are wrong.(they have to be the other way round)

[@akilkarthikeyan]

Yep they're the other way round

[@RahmaElsaeed-cf6ru]

Good

[@steverok67]

That is one cool drawing board. 15 minutes in, and we are only four information bit intervals into a 4-state trellis. Wouldn't a top-down derivation from theory into a generic algorithm be a better way to teach it ? In practice, soft decisions can be much more powerful, especially in non-uniform channels. In that case, it is no longer Hamming distance. There are other nuances like pruning the initial and final stages. In the end, a simulation model measuring performance versus complexity, with and without various algorithm features, is, ultimately, invaluable in making design trade-offs. Anyway, sorry, don't even know the audience here. Love this stuff. Just happy to see that classic communication theory hasn't gone out of style.

[@seshu6617]

at last another path is also there know with least cost .
in which i got 00 01 01 10 10

[@t.on.y]

thx dude

[@ie7458]

If u end with 00 u dont have 2 choices

[@chakib2378]

I hope the trellis in the left is wrong otherwise I have understand nothing :D

[@kimmisoo7743]

It must be a bit confusing since you are writing it in reverse way..
Needs practice 👌💪

[@c4alexc4]

He probably writes normal and instead flips the video before he uploads it.

[@amadoucoulibaly6439]

thank you