M-PSK Modulation and demodulation Sync

Hello,
I have a problem with M-PSK modulation and demodulation. I think its because of sync... but i am not sure. My problem is; when i try to comare my modulators input bit stream and my demodulators output stream they are different . I mean they are so much different it has BER=1 . I export my modulators input bitstream and my demodulators output bitstream to exel, i compare them , they are very very different. How can i fix it? i want to calculate BER and draw its BER-EB/N0 graph. first i need to compare them but i cant. waiting for helps . have a nice day.