Sub-channel equalizer design based on geometric interpolation for FBMC/OQAM systems

The interpolation of complex signals is frequently encountered in the signal processing chains of high performance transmission systems. Linear interpolation might be inappropriate for this kind of situation and, here, geometric interpolation is proposed instead. Specifically, it is proposed, in a Filter Bank-based Multi-Carrier/Offset QAM (FBMC/OQAM) transmission system, to use geometric interpolation to determine the frequency domain intermediate points of each sub-channel needed to calculate the T/2-spaced sub-channel equalizer coefficients at the beginning of the burst. The equalizer coefficients are computed using the inverse fast Fourier transform (IFFT). This equalizer must compensate ISI and ICI caused by a selective channel and timing offset. Simulation results demonstrate the effectiveness of the proposed equalizer.