Intercarrier interference in ofdm

Intercarrier Interference (ICI) is an impairment well known to degrade performance of Orthogonal Frequency Division Multiplexing (OFDM) transmissions. It arises from carrier frequency offsets (CFO), from the Doppler spread due to channel time-variation, and, to a lesser extent, from sampling frequency offsets (SFO).

1. Is OFDM sensitive to Doppler shift?
2. What are the effects of frequency offset in OFDM system?
3. How orthogonality is maintained in OFDM?

Is OFDM sensitive to Doppler shift?

Orthogonal frequency-division multiplexing (OFDM) is robust with multipath interference; however, it is sensitive to Doppler.

What are the effects of frequency offset in OFDM system?

Orthogonal frequency division multiplexing (OFDM) is orders of magnitude more sensitive to frequency offset than single-carrier systems. Frequency offset reduces the signal power and destroys orthogonality among subcarriers leading to the intercarrier interference (ICI).

How orthogonality is maintained in OFDM?

In OFDM, the subcarrier frequencies are chosen so that the subcarriers are orthogonal to each other, meaning that crosstalk between the sub-channels is eliminated and inter-carrier guard bands are not required.