After reading the original paper, you've meant "2D- or 3D-DCT" :) On Sat, 2019-05-25 at 21:20 +0100, farid mihoub wrote: > Hi, > Discrete cosine transform > > > 25.05.2019, 21:02, "Marcus Müller" <mmuel...@gnuradio.org>: > > hi, what's 2DCT_or_3DCT? > > > > Best regards, > > Marcus > > > > On Sat, 2019-05-25 at 19:38 +0100, farid mihoub wrote: > > > My application is to broadcast a video using softcast approach. > > > Video-->2DCT_or_3DCT-->Floating coefficients-->complex_mapping > > > -->ofdm_phy > > > My video quality (PSNR) will depend linearly to my SNR so no > > > need to > > > have an adaptive modulation. > > > > > > > > > 25.05.2019, 18:27, "Marcus Müller" <mmuel...@gnuradio.org>: > > > > 1- So, you have an SNR of best-case 16 dB; that's not high for > > > an > > > > OFDM > > > > system. > > > > > > > > 2- No, there's no power normalization. Hint: you can look all > > > this > > > > up > > > > by actually looking inside these blocks! This would make a lot > > > of > > > > sense, since it sounds you don't actually want to use tzhe > > > OFDM > > > > blocks > > > > at all. The whole advantage of the OFDM blocks compared to > > > just > > > > doing > > > > an IFFT of your transmit vector is that you get a header and > > > > modulation > > > > scheme. > > > > > > > > 3- Not quite sure what "information is linearly related to > > > complex > > > > symbols" means? Can you elaborate? > > > > 3b- A case where you *don't* do FEC is either a non- > > > communications > > > > system (i.e. you don't actually want to do OFDM for the reason > > > of > > > > transmitting information) or the extremely-bad-SNR case (where > > > FEC > > > > makes your BER better). For both cases, the existing OFDM > > > blocks > > > > are > > > > more of an obstacle than a solution. > > > > > > > > What are you building? What is your overall application. > > > Please > > > > paint > > > > the bigger picture – it's a bit frustrating to try to help > > > you, but > > > > then only get told that "this is not how I want to do it". > > > > > > > > Best regards, > > > > Marcus > > > > > > > > On Sat, 2019-05-25 at 18:39 +0200, Marcus Müller wrote: > > > > > Dear Farid, > > > > > > > > > > please always respond on the mailing list. > > > > > Thank you, > > > > > Marcus Müller > > > > > > > > > > On Sat, 2019-05-25 at 17:36 +0100, farid mihoub wrote: > > > > > > 1- For the noise : in the TX side the output is in the > > > order > > > > > of 2A, > > > > > > the noise 0.05A. > > > > > > 2-Second even without noise, the const does not affect the > > > > > > transmission, is there any sort of power normalization? > > > > > > 3-For the FEC and the modulation I want to try my custom > > > > > mapping > > > > > > where information is linearly related to complex symbols, > > > and > > > > > my > > > > > > application doesn't require error correction. > > > > > > > > > > > > Thank you. > > > > > > > > > > > > > > > > > > 25.05.2019, 17:06, "Marcus Müller" <mmuel...@gnuradio.org> > > > : > > > > > > > Hello Farid, > > > > > > > On Sat, 2019-05-25 at 15:59 +0100, farid mihoub wrote: > > > > > > > > Hello, > > > > > > > > > > > > > > > > In the OFDM_tx, rx examples in gr-digital : > > > > > > > > 1- Why just a low level of noise affect the > > > transmission > > > > > and > > > > > > > > cause it > > > > > > > > to stop. > > > > > > > > > > > > > > "low" is relative. It seems it's high enough to cause > > > packet > > > > > > > losses, > > > > > > > iff it's actually the noise. > > > > > > > > > > > > > > > 2- in the the Tx output and the Rx input no matter the > > > > > value > > > > > > > > of > > > > > > > > the > > > > > > > > multiply constant we apply > > > > > > > > that would not affect our transmission. > > > > > > > > > > > > > > Then it's probably not only the noise! > > > > > > > > > > > > > > > 3- Is there any way to separate channel estimation and > > > > > > > > tracking > > > > > > > > from > > > > > > > > data transmission, sometime I get the error "invalid > > > > > packet > > > > > > > > detected!" form the packet parser, also I need my data > > > to > > > > > > > > bypass > > > > > > > > FEC > > > > > > > > and QAM. > > > > > > > > > > > > > > Um, prior to QAM demodulation there is no data, and > > > prior to > > > > > FEC > > > > > > > decoding there is no information bits, so I'm not sure > > > what > > > > > you > > > > > > > want? > > > > > > > > > > > > > > > My purpose is to stream raw complex data to the I/Q > > > > > > > > components > > > > > > > > directly. > > > > > > > > > > > > > > Then it seems you don't want an OFDM transceiver but > > > maybe > > > > > just > > > > > > > simply > > > > > > > a single IFFT? Not quite sure what you have in mind. > > > > > > > > > > > > > > Best regards, > > > > > > > Marcus > > > > > > > > > > > > > > > > > _______________________________________________ > > > > > Discuss-gnuradio mailing list > > > > > Discuss-gnuradio@gnu.org > > > > > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > > > > > > > > > > > _______________________________________________ > > > Discuss-gnuradio mailing list > > > Discuss-gnuradio@gnu.org > > > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
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