We have seen in Section 2.5 that the main issue with CFO is that it introduces two distinct components which degrade the overall system performance. For each subcarrier the two deleterious effects are
In addition, from one OFDM symbol to the next CFO also introduces another deterministic phase increment to the subcarriers depending on the OFDM symbol duration. Taking the first symbol as the reference, i = 1, the phase rotation introduced by CFO for symbol i is
where i is symbol index, ΔCFO is the CFO in hertz, Δf is the subcarrier spacing in hertz, Ns = Ng + N is the number of points of a single OFDM symbol including the guard interval, and Ts is the sampling frequency.