[HN Gopher] The history of orthogonal frequency-division multipl...
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The history of orthogonal frequency-division multiplexing (2009)
Author : teleforce
Score : 36 points
Date : 2024-08-13 07:58 UTC (2 days ago)
(HTM) web link (ieeexplore.ieee.org)
(TXT) w3m dump (ieeexplore.ieee.org)
| brudgers wrote:
| https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=530...
| floam wrote:
| Neat. Can one resolve the _arnumber_ parameter stamp.jsp takes
| for articles in general or did that require being logged in?
| floam wrote:
| Hmm, looking into it myself, it looks not generalizable,
| short of searching for the document title and hoping you get
| lucky. This wasn't a direct paywall bypass.
|
| It looks like this is actually just a version of the document
| published a different way.
|
| Posted to HN from _IEEE GLOBECOM 2008 - 2008 IEEE Global
| Telecommunications Conference_ :
|
| https://ieeexplore.ieee.org/abstract/document/4698465
|
| Same thing but free from _IEEE Communications Magazine, vol.
| 47, no. 11_ :
|
| https://ieeexplore.ieee.org/abstract/document/5307460
|
| Person I replied to clicked the PDF button on the freely-
| available version.
| brudgers wrote:
| I think I remember IEEE making everything available a few
| years ago...there's probably an HN discussion if it
| happened (but it might have been ACM (or both)). If so,
| this would be an ordinary dark pattern of extracting
| payment where it is not absolutely necessary.
|
| Anyway, I googled the title based on my possibly accurate
| memory.
|
| In fairness my impression is that very few HN members 'give
| back' by joining such organizations. It's not part of
| today's startup mindset.
| Jtsummers wrote:
| ACM is the one pushing towards open access for
| everything. IEEE is not as far along with that. It gets
| really annoying, I'm a member of a couple IEEE societies
| and find that I have to use my institutional login (GA
| Tech in my case) to reliably get access to their
| publications. With ACM, I join a SIG and I pretty much
| get the entirety of the SIG's digital library (even
| before the bigger open access push).
| Liftyee wrote:
| OFDM is one of those technologies that I haven't been able to
| conceptually grasp. Thinking in a frequency/phase space instead
| of a (DC) voltage/time space hasn't quite "clicked" for me yet.
| paulgerhardt wrote:
| I found this playlist to be one of the better explanations:
| https://www.youtube.com/watch?v=F6B4Kyj2rLw&list=PLx7-Q20A1V...
| drmpeg wrote:
| Stupid OFDM tricks.
|
| https://www.youtube.com/watch?v=saac0ZtTeX4
| paulgerhardt wrote:
| Fun. You should link the github in the youtube. I assume it's
| this one? https://github.com/drmpeg/gr-paint
| drmpeg wrote:
| Yes, that's the one. I also have a more useful OFDM project,
| an ATSC 3.0 transmitter.
|
| https://github.com/drmpeg/gr-atsc3
| jhallenworld wrote:
| This is a great talk if you want to know how it's implemented:
|
| "Recent Interesting and Useful Enhancements of Polyphase Filter
| Banks: fred harris"
|
| https://www.youtube.com/watch?v=afU9f5MuXr8
| drmpeg wrote:
| No, that has nothing to do with OFDM.
| nakulgarg22 wrote:
| Orthogonality is a beautiful concept.
|
| In physics, different frequencies don't interfere with each other
| --they're always independent. However, in digital operations and
| mathematics, this isn't automatically true, so we need to
| carefully select the right frequencies.
|
| OFDM leverages this by ensuring that, in the frequency domain,
| certain frequencies remain completely separate, meaning changes
| to one frequency (in amplitude or phase) won't affect the others.
|
| This allows us to capture the maximum information with limited
| samples.
| jjtheblunt wrote:
| > In physics, different frequencies don't interfere with each
| other--they're always independent.
|
| Are you overlooking harmonics? Are you overlooking the same
| frequency case of noise cancellation, via phase shift?
| layer8 wrote:
| Phase shift isn't different frequencies?
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(page generated 2024-08-15 23:01 UTC)