A comparison among interference approximation methods for OFDM/OQAM

In the studies of 5th generation (5G) wireless communication systems, an alternative method to orthogonal frequency division multiplexing (OFDM) used for 4th generation (4G) systems is still being investigated. OFDM with offset quadrature amplitude modulation (OFDM/OQAM) is one of these alternatives. Due to the reasons such as absence of cyclic prefix (CP) in its structure and perfect separation between non-adjacent subcarriers make OFDM/OQAM an important alternative for 5G. However, when the channel estimation methods for OFDM are directly applied to OFDM/OQAM, an intrinsic intersymbol interference (ISI) is observed and it makes OFDM/OQAM sensitive to Rayleigh fading channels. For this reason, various channel estimation methods specific to OFDM/OQAM have been developed. One of these methods is interference approximation method (IAM). The method not only eliminates intrinsic ISI, but also improves the system performance against noise. However, it also increases the peak to average power ratio (PAPR). In this paper, we will compare the performance of different IAM types in terms of PAPR and noise power.