Dear GNU Radio Community,
since a couple of months i try to get a 256-QAM Transmission over Air to work. Now i reached a dead point, because i could not get the receiver locked on the phase of the QAM. 4-QAM is not a Problem, it works fine like it is described in the Tutorial. I have tried Polyphase Clock Sync, Costas Loop ect. (what ever i found under Synchronizers) in quite various combination, but this leads to nothing. My guess is that Costas Loop is not working for higher QAM anyway. I did not find any description, how this could be done right, neither in the Internet (Google, Youtube) nor in the library of our University. Helpful would be: - a generic description or example how this is done - a reference one a book or paper which describe that (even if this book is expensive) - link to an online-resource Thanks in advance Best regards Leonhard
