Phase Noise in MATLAB OFDM

[sandalwalk]

Hi,
I want to know which order each item should be implemented in MATLAB OFDM simulation.

(1)
IFFT=>Phase noise (TX)=>Phase noise (Rx)=>AWGN=>phase compensation.

or

(2)
IFFT=>Phase noise (TX)=>AWGN=>Phase noise (Rx)=>phase compensation.

Which is correct ?
Somebody please advise.

Cheers,
K

 

[kalyanasv]

It all depends what sort of Phase noise your adding. If it is a constant noise then either one shouldn't matter. If you using a non-linear phase noise then to be conforming to a practical system, you should go with (2).

 

[Blue_Angel]

hi.. i think you are dealing with phase noise in OFDM system due to the oscillator non idealities.. practical oscilators cannot produce a pure sine wave of a constant frequency. this phenomenon is then modelled as phase modulation...if i am right till now then u shud do it like this

transmitter = [modulation----->IFFT]----->
Channel = ( h = 1 for non fadind channel i.e AWGN)------->
Receiver = --->[+AWGN----------> add phase noise---->FFT]

Add phase noise after AWGN...phase compensation comes before FFT if its a time domain method. it is done affter FFt if its a freq domain technique