4 ms·

Demodulation of LTE PUCCH

14 points by picture 5y ago

ThePowerOfFuet 5y ago
>The reason why this technique doesn’t work is essentially that the PUCCH is too narrow. Its bandwidth is 180 kHz, while the reciprocal of the cyclic prefix duration Tcp is 213.33 kHz (or 192 kHz for the cyclic prefix of the first symbol, which is slightly longer). This means that, forgetting about the fact that the PUCCH transmission is not at baseband (which doesn’t matter, because the carrier frequency is cancelled in the correlation), the time-domain PUCCH waveform is more or less constant in every interval of length Tcp. This causes the correlation to be large regardless of whether t is aligned to the start of the cyclic prefix or not. I wish this was explained a bit better; this feels like it was written for only those with the same level of experience as the author.