Dear Ravil and Sam Sung.
I attached my file. In this file, i tried to re-arrange an optisystem example from this website.
My problems:
1) I cannot LED as a light source. Also, I cannot use laser for visible range. Both of them gives no result or bad results.
2) In this file, if i use 4-QAM, there is no problem. But, if I use 16-QAM, i cannot get acceptable results.
Thank you.
Regards.