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" <[email protected]>: > > 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" <[email protected]>: > > > > > 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 > > > [email protected] > > > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > > > _______________________________________________ > Discuss-gnuradio mailing list > [email protected] > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio _______________________________________________ Discuss-gnuradio mailing list [email protected] https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
