Hi Ravil,
Thanks for your reply and useful links. I would also like to know you opinion about the reason for the symbol rotation and why it is different in different OFDM channels. Others seem to think it’s because of nonlinearities. And I’m looking for some type of equalization that has the same effect on my system as changing the initial phase of LO laser does, which is preventing symbol rotation and not necessarily giving a more clear constellation diagram.