Effect of carrier frequency offset on offset QAM multicarrier filter bank systems over frequency-selective channels

This paper presents an analysis of the effect of carrier frequency offset (CFO) on offset QAM (OQAM) multicarrier filter bank (MCFB) systems, also known as staggered modulated multitone (SMT), over frequency-selective channels. This effect may be quantified by signal-to-interference ratio (SIR). We drive an accurate expression for the interference power and the desired signal power. Then SIR of SMT systems is calculated. Next, we drive an approximated SIR when the maximum delay of the channel is small in comparison with symbol spacing. The approximated SIR show that the SIR over frequency-selective channels converges to that over additive white Gaussian noise (AWGN) channels. Numerical results show that with increasing number of subcarriers, both of accurate and approximated forms of SIR as a function of CFO over frequency-selective channels converge to that over AWGN channels. Also, we compare SMT and orthogonal frequency division multiplexing (OFDM). It is shown that OFDM has better SIR in small CFO over frequency-selective channels. But with large number of subcarriers or high CFO, SMT outperforms OFDM.