DSSS - Direct Sequence Spread Spectrum

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Күн бұрын

In 802.11 standards, three different modulation/transmission methods are used to transmit wireless signals: 1) Frequency Hopping Spread Spectrum, or FHSS; 2) Direct Sequence Spread Spectrum, or DSSS, and 3) Orthogonal Frequency Division Multiplexing, or OFDM.
These techniques are used for several reasons, including the reduction of natural interference, noise and jamming, and prevention of detection and interception.
In this lesson, I will focus on DSSS.
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Пікірлер: 134

@curtvincent3355 3 жыл бұрын

I am a retired Army Signal Officer. I wish I had Sunny when I was a Lieutenant! Smart guy, really explains things well. Thank you Sunny!

@sunnyclassroom24 3 жыл бұрын

Many thanks!

@sachinfulsunge9977 2 жыл бұрын

Well i thought you were in cyber security?

@curtvincent3355 2 жыл бұрын

@@sachinfulsunge9977 I am! Founder of a very large practice with a Wall Street firm. But Cyber Security is a massively wide subject, not just technical. Includes people and physical (ever heard of dumpster diving?? No CAT5e there! LOL). Sunny's lectures really help plug up holes in my knowledge or things that are excellent refreshers. He is a brilliant teacher. I really appreciate him.

@sachinfulsunge9977 2 жыл бұрын

@@curtvincent3355 I see. I appreciate him as well :)

@marialuna4470 Жыл бұрын

Yô Ku Ku youiy😮😊o

@onnguyen3408 2 жыл бұрын

Thank you Sunny, you are the best telecommunication professor I have ever seen.

@antoniopintus8568 3 жыл бұрын

You are simply a master class teacher! smooth , calm and clear ! not a common thing really !

@sunnyclassroom24 3 жыл бұрын

Thanks! 😃

@overdrijft 4 жыл бұрын

You're the best, Sunny! All of your videos are ever so helpful.

@sunnyclassroom24 4 жыл бұрын

Thanks.

@getanehgeto7873 2 ай бұрын

A lecture who can be a role model for others, God bless you!

@srb1855 5 жыл бұрын

Sunny all of your videos are excellent! Thank you for all your effort and exquisite execution.

@sunnyclassroom24 5 жыл бұрын

Thanks a lot for your compliment and encouragement.

@taguetrash 3 жыл бұрын

Possibly the only good visualization and explanation of this concept on KZfaq!

@manafsliman3734 2 жыл бұрын

You sir, for sure deserve more subscribers and viewers, thank you so much for your work.

@thezombieguy426 3 жыл бұрын

out of all videos I pick yours because the way you explain concepts is clean and simple to understand

@sunnyclassroom24 3 жыл бұрын

Thank you for watching! I appreciate.

@user-hg9cc7rz9d Ай бұрын

You are my life saver. Keep it up with the good work.

@080_cse_sanjaykarthicks4 2 жыл бұрын

Thank you for this awesome lecture This guided me to understand this concept and i'm feeling bit more confident to take seminar on this topic after watching this video

@mohamedisaac924 3 жыл бұрын

man you are even better then my teachers i learned a lot from you thanks ( you're the man )

@jakubadamczewski3477 5 жыл бұрын

You saved my time, amazing video! Thanks!

@raymondthalseth3920 5 жыл бұрын

Fantastic! Thanks :) The use of more than one example is so helpful :)

@kirklawrence4326 2 жыл бұрын

excellent job at explaining. Clear and concise.

@user-ie1nx6ju2h 2 жыл бұрын

No words can describe how much l'm grateful . Gog bless you ❤️

@drvisalakshipalanisamy6188 5 жыл бұрын

Excellent video lectures . Every concept is covered in a simple and clear manner.Hats off.

@sunnyclassroom24 5 жыл бұрын

Thanks a lot for your nice comment.

@hanjoradja569 5 жыл бұрын

Good Job Sunny, your video is very helpful, explain with a gentle clearly sound.. make me easy to understand.. GREAT!

@sunnyclassroom24 5 жыл бұрын

Thank you very much, Hanjo!

@Thinkchronous 5 жыл бұрын

great explanation. I liked how your words were in sync with the animation!

@sunnyclassroom24 4 жыл бұрын

Thanks a lot for your comment.

@rogeliovegam 5 жыл бұрын

Sunny you are a Genius. !!!. Thanks for this clear explanation

@sunnyclassroom24 5 жыл бұрын

you are welcome and thank you for your kind words, Rogelio.

@srinaath9845 4 жыл бұрын

Thank you Sir.You help me out every semester.

@f4z0 5 жыл бұрын

Excelent job, super clear explanation.

@rushikeshwaghmares6476 Жыл бұрын

So easy to understand concepts , thanks

@maxwellchiu6859 2 жыл бұрын

Hey Sunny: You didn't mention it but you are actually talking about Barker Codes. I have been looking into Barker Codes and Convolution and this video actually filled in a lot of gaps in my understanding of Barker Codes. I'm not really there yet with Barker Codes, but this video sure helped me get closer. Thanks very much.

@user-mh7xb4wo5l Ай бұрын

Thank you, sir! You are doing a great job.

@Abiwrl 5 жыл бұрын

Amazing! Thank you Sunny!

@sunnyclassroom24 5 жыл бұрын

You are welcome!

@shreyaovalekar6764 5 жыл бұрын

Thank u so much! U made the topic easy to understand

@richenjoshi7054 2 жыл бұрын

You explained it so well, thanks

@sudarshandevarasam 5 жыл бұрын

you saved me, thank god for sunny

@sunnyclassroom24 5 жыл бұрын

God bless!

@PatelJitendrabORN2sUCCEED 3 жыл бұрын

wow, Plain and simple.. thankyou

@raviroogi9030 2 жыл бұрын

Good sunny, I really appreciate your smart explanation

@allthingsikki7659 3 жыл бұрын

SOOO much helpful, Thank you!

@mariodelzo 4 жыл бұрын

One more great video. Thank you!!

@sunnyclassroom24 4 жыл бұрын

My pleasure!

@keertivaassankaranarayanan3117 4 жыл бұрын

Nice video to understand concepts!

@qiucuojimei5852 3 жыл бұрын

Thank you very mich for your great explanation.

@user-st7cj3vz3x 5 жыл бұрын

I say to myself that I do really enjoy watching your video.

@sunnyclassroom24 5 жыл бұрын

Thank you very much!

@Infinity2zer0 2 жыл бұрын

Really useful, thanks, that's amazing

@anggasukmabahari6342 3 жыл бұрын

This video are the best! Thank you sir!

@sunnyclassroom24 3 жыл бұрын

You're very welcome! Thank you for watching!

@testuser_tgo 2 жыл бұрын

Tks so much my man!

@cheelikumar 4 жыл бұрын

best clear & concise explanation sunny....love from india

@sunnyclassroom24 4 жыл бұрын

Thank you very much! Thanks from Kansas, USA.

@mohammedjawadkalburgi2208 5 жыл бұрын

no doubt ,ur greatest of all

@shanahmed9710 5 жыл бұрын

Hats off!

@deshantdevkota2563 2 жыл бұрын

Thank you sir.

@augmentos 3 жыл бұрын

Awesome as always Sonny. I wonder can FHSS them be blocked/jammed or interupted? Or is it otherwise the most resilient?

@windogwow 2 жыл бұрын

This is gold! I do have couple of questions: 1. What is narrowband and wideband? 2. If the bandwidth or the “spread” of a narrowband signal becomes “wider” as shown in the diagram, wouldn’t it cause interference with adjacent frequencies and also become “weaker” to travel far distance? Thank you!

@SuppaBoii 4 жыл бұрын

Good Job man !!!!!

@sunnyclassroom24 4 жыл бұрын

Thanks!

@maathoukbenziane1087 3 жыл бұрын

tnks sunny

@sangeethmv1233 4 жыл бұрын

Very effective teaching....

@sunnyclassroom24 4 жыл бұрын

Many many thanks

@stepannovotny4291 9 ай бұрын

I don't see how you could achieve a 10:1 frequency spread at the physical layer using DSSS, whereas with FHSS you can simply have two receivers where one is tuning while the other is receiving. Any comments? A video on the physical layer would be very valuable. Nice channel by the way!

@udayposia8082 5 жыл бұрын

Best explanation ever, Thank you :-)

@sunnyclassroom24 5 жыл бұрын

You are welcome!

@brajmandloi6232 5 жыл бұрын

Great explanation.

@sunnyclassroom24 5 жыл бұрын

@@brajmandloi6232 thanks

@Nath-pk5nk 3 жыл бұрын

Great video. Can you explain how increasing the spreading factor effects the bit error rate ?

@linn8007 3 жыл бұрын

you are brilliant

@archanarajr6580 Жыл бұрын

Thanku sir..

@rasswanth4968 5 жыл бұрын

Good one.

@sunnyclassroom24 5 жыл бұрын

thanks.

@alalolol9949 2 жыл бұрын

Thanks for this wonderful video. Could you further explain how DSSS makes Inter-Symbol Interference negligible in the multi-path scenario?

@MegaJohnhammond Жыл бұрын

One of the best benefits is you can transmit multiple channels on the same frequency using different codes for each channel. That's how GPS satellites work.

@jung1020lee 4 жыл бұрын

i have one question. I have seen a solution that converts and transmits a dsss signal in reverse phase. Is there a difference between normal dsss transmission and reverse phase transmission?

@kalamsha3044 4 жыл бұрын

thank you

@sunnyclassroom24 4 жыл бұрын

You are welcome!

@ganeshsahane5766 4 жыл бұрын

thank

@sunnyclassroom24 4 жыл бұрын

you are welcome

@arsalalam5998 2 ай бұрын

nice.

@Mr_ASIC 2 жыл бұрын

how transmitter and receiver sync the PN code to demodulate data ?

@ziapracticalwork7007 3 жыл бұрын

sir which one is most suitable spread spectrum techniques in term of providing security in wireless networking

@nickanderkay7148 3 жыл бұрын

So what is better dsss or fhss? And can unrelated this to dsmr as used by spektrum in rc applications?

@mdsakilbhuiya8689 2 жыл бұрын

Sunny, you are a great teacher.thanks a lot.

@kiwiaburridoo 3 жыл бұрын

I don't understand why it is likely to have low-power signals. Don't make them more difficult to diferentiate them from awgn noise? Sorry if I missed something actually obvious, I'm beginning to learn about data transmission. Oh, and great video Sunny!

@ananthu4141 Жыл бұрын

Sir What we do in case of Barker 11 sequence provided with an original data of 3 bits

@hassan_mohd 4 жыл бұрын

Thanks thala..

@sunnyclassroom24 4 жыл бұрын

You are welcome!

@needsomehike 4 жыл бұрын

at 05:40 Sunny says lower power = harder to detect and interfere. But lower power also means that the SNR will be lower so the signal will be more effected by noise=less reliable connection. Can someone please explain that how lower power is better to avoid interference?

@makharsa12 4 жыл бұрын

yes, this is the idea of the whole DSSS. you need to send at a much lower power because your signal is supposed to look like random noise with low power. But the cost you are paying however, is widening the frequency band (and this what we are doing by XOR your normal data rate to a much higher data rate at 3:25 , you are increasing the bandwidth more of that what you really need) and using all of your available bandwidth to send the one signal. DSSS utilizes the whole bandwidth to lower the SNR needed to be transmitted. when you are sending multiple signals, PNs should be different and all of the signals should have minimal power to avoid having one stronger signal than others. because you are basically using the same bandwidth for all of these signals. And if all your PNs are well crafted to be unrelated to other PN, you can reconstruct all of your signals at the receiving end

@fahadalhussein5407 3 жыл бұрын

at the receiver end when you do the mathematical operation of correlation with PRN of the RX ( as part of demodulation ), the desired signal will increase in magnitude, on the other hand correlating anything unwanted ( noise , interference etc ) that enters the receiver will result in a low output. for the sake of security, you want your signal to hide in the wireless channel like if it is noise . I might be wrong.

@uttamsharma6358 3 жыл бұрын

Great explanation. I am curious that when is the PN sequence decided and by whom? I know about shift registers but is it decided before session starts or does it keep changing in the middle of session? Is it multi-casted by transmitter or something else?

@tomatrix7525 3 жыл бұрын

I think the Wireless adapter chooses it at the start of session by randomely choosing an n bit encoding. And there is practically no chance any other device in area will be on that exact same n bit encoding. The probability is negligable.

@windogwow 2 жыл бұрын

I am only assuming this PN code would be something similar as a “private” key in crypto world which is exchanged before passing data and can be constantly changed for security purpose.

@mmkvhornet7522 8 ай бұрын

i believe that the PN sequence is agreed upon beforehand

@Felink21 5 жыл бұрын

Always use OR table?

@damaylaphoenix1155 4 жыл бұрын

which is better ?

@NA12495 3 жыл бұрын

Do you have a more in-depth explanation as to why it is immune to noise?

@aaronacj 3 жыл бұрын

hope this helps get me through CISSP...

@CuongHut 4 жыл бұрын

Thank you sir for your video. But as I was taught, when data is modulated with PN code, 1 and 1 is 1, not 0 as your instruction. Correct me if i am wrong. Thank you

@sunnyclassroom24 4 жыл бұрын

we use different table. Exclusive OR truth table and Truth table (which you mentioned) is different.

@CuongHut 4 жыл бұрын

@@sunnyclassroom24 I got it, thank you so much.

@muhammadsharifhaider2038 2 жыл бұрын

Sir, I think in the truth table 1 and 1 using OR Truth table results 1.

@lowspoke9974 5 жыл бұрын

Set 1.25 speed before watching

@shaunwong7870 5 жыл бұрын

prefer setting 1.5 speed LMAO

@davidwarner2491 3 жыл бұрын

@@shaunwong7870 me too

@mohammedjawadkalburgi2208 5 жыл бұрын

keep posting please

@ojaspurohit5852 3 жыл бұрын

Why is usage of more BW a benefit?

@rheniuspaul389 Жыл бұрын

Hello there sir first of all this lecture is op and pease make full video if possible with mathematical analysis and the demodulation part thank you

@ahmednor5806 4 ай бұрын

🙏🙏🌹🌹

@WoWPro71 Жыл бұрын

Isn't it supposed to be XNOR and no XOR?

@adityachopra3759 5 жыл бұрын

Looks like a cooking class

@tomhardy6643 4 жыл бұрын

Could U please put the all u wanna say as a text in description?

@sunnyclassroom24 4 жыл бұрын

will do.

@piyushgarg2402 4 жыл бұрын

bhaiyon aur behno is video ko like karo

@dungngoviet1834 5 жыл бұрын

OR truth table ?? this is XOR

@sunnyclassroom24 5 жыл бұрын

XOR is exclusive truth table, which is different from OR truth table.

@DrN007 4 жыл бұрын

I don't get how it's "spreading" frequency of the signal. Based on the explanation, it's only increasing the frequency required to transmit, while still keeping it narrowband.

@DrN007 4 жыл бұрын

Unless, it applies many different PNs & transmit them simultaneously?!

@anurag_singh123 3 жыл бұрын

I always watch this in 2x speed.

@user-tg6gn8st2v 3 ай бұрын

@johnaweiss Жыл бұрын

6:08 Sunny, FHSS was developed in 1942 by a Jewish American refugee who became a Hollywood actress. She invented it to help the Allies defeat the Nazis, but the military REJECTED FHSS, and didn't use it until the 1960's. "Frequency-hopping spread spectrum (FHSS) radio technology was originally patented on August 11, 1942, by actress Hedy Kiesler Markey (Hedy Lamarr) and composer George Antheil. It was originally designed to be a radio guidance system for torpedoes, a purpose for which it was never used. The idea of spread spectrum was ahead of its time. During World War II, Lamarr learned that RF-controlled torpedoes of the United Sates Navy, could easily be jammed by the enemy and veered off-course. This made it more difficult to sink the enemy’s ships. So, Hedy Lamarr brilliantly came up with the idea of a frequency-hopping RF guidance system that would be very hard to jam. Together with George Antheil, they created a RF transmitter device that emulated player-piano capabilities… and frequency hopping was born. They filed a patent in 1942, however, the US government immediately classified the technology. FHSS was not used in time for World War II. It was not until 1957 that further development on spread spectrum occurred [at Sylvania Electronics], and in 1962 frequency-hopping (FHSS) was used for the first time between the US ships at the blockade of Cuba during the Cuban Missile Crisis." www.extremenetworks.com/extreme-networks-blog/happy-birthday-hedy-lamarr-wi-fi-visionary