I was reading someone's thesis and now i am more confused about CDMA system. From what i understood is CDMA is multiplexing which allows multiple signals to transmit over single channel. so general structure of CDMA communication system should be like shown below:
Binary Data --> Multiply PN Code --> XOR(spreading) -->BPSK/QPSK Modulation --> RF End | Channel | Restore Data <-- Despreading <-- Aquistion and lock <-- RF Demodulation <-- RF Reception
And Now I had come across block diagram in the thesis, Pg.27 which basically modulate and they do spreading.
From my understanding it should be spreaded before doing modulation. This is my understanding, please correct me if i am wrong.
But can someone please confirm which one is right ? It would be great if you explain a little bit.