OFDM/OQAM-IRS System With Imperfect CSI

This study investigates offset quadrature amplitude modulation (OQAM) based orthogonal frequency division multiplexing (OFDM) waveform in conjunction with intelligent reflecting surfaces (IRS). For an OFDM/OQAM-IRS system, a frame structure is conceived for channel frequency response (CFR) estimation using an ALL-ON technique, followed by IRS reflection coefficients optimization using two methods based on maximizing the effective channel power. The computational complexities of both methods are derived. We analyze and demonstrate, through numerical examples, the effect of guard symbols in the OFDM/OQAM-IRS frame on CFR estimation and spectral efficiency. The simulations also showcase the performance gain of the proposed optimization schemes over the random selection of the IRS phase and OFDM/OQAM systems without IRS.