Combined Effect Analysis of Wiener Phase Noise and Doppler Spread in OFDM Communication System

We derive an exact closed-form expression for the SNR degradation due to the combined effect of Wiener phase noise and Doppler spread in the OFDM system corrupted by shadowed multipath effect. The derivation depends on the continuous time signal model analysis assuming the subcarrier data symbols are constants. A simple approximate SNR degradation formula is obtained for slow fading channel, small phase noise effect and small phase noise linewidth-to-maximum Doppler frequency ratio. This approximate formula shows that the degradation factor in dB is the summation of the degradation factor in dB due to the phase noise effect only and the degradation factor in dB due to the Doppler spread only