Imperfections in an OFDM System | Carrier Frequency Offset (CFO)

This video explains about CFO.
Source of CFO
Impact of CFO
Signal Model of CFO
Estimation and Compensation technique of CFO
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[@arjunmenonkandanat6328]

Thanks a ton for this video

[@ThePbilling]

Good video! Thanks for publishing this. I have one doubt though. You showed the phase shift in time domain, and mentioned this is what causes phase to rotate in the constellation diagram. We have phase shift in time domain x[n] And constellation diagram is plotted post FFT (i.e frequency domain), so any phase shift in time domain will port as a freq shift in frequency domain(post FFT). So this should not show up as phase rotation in freq domain. i have simulated this in past and know the circular diagram is what we see. But just got confused because of the reason above. can you please clarify this?

[@curiousbeing8585]

Hi Prabhjot, that's a great question. The rotation of the constellation (Post FFT) is not the same as rotation in the time domain. The one above is for representation and easy understanding of the impairment. Basically, CFO will cause scaling and ICI in Frequency Domain which will cause distortion and rotation in the constellation.

[@eliseolopez2790]

I don't understand

[@jjjyotish]

Coherence BW will of course have an effect on deciding your SC spacing. U want the SC spacing to be less than coherence BW to avoid ISI.

[@eliseolopez2790]

I don't understand math

[@rishabhsrivastava1241]

This answers your question itself, first do the math on your own and then re watch the video