Low-Complexity Equalization Scheme for Multicarrier Offset-QAM Systems

Multicarrier offset quadrature amplitude modulation (MC-OQAM) systems show a high degree of spectral efficiency and flexibility. However, the typical equalization method for MC-OQAM systems, the phase-corrected equalizer, has a large complexity because it uses several equalizers in parallel in order to cope with the inter-carrier interference problem. In this letter, we propose a low-complexity scheme for frequency-domain equalization with interleaved training sequences (FDE-ITS). Despite its low complexity, the FDE-ITS achieves the same phase noise tolerance and bit error rate (BER) performance against amplified spontaneous emission noise as the phase-corrected equalizer in MC-OQAM polarization division multiplexing (PDM) system simulations. In a 206.6-Gb/s PDM MC-16OQAM back-to-back experiment, the FDE-ITS and the conventional phase-corrected equalizer show 1.4-dB optical signal-to-noise ratio penalty over the additive white Gaussian noise theory at a BER of $10^{-3}$ . Due to its good performance and low computational complexity, the FDE-ITS is a promising equalization scheme for MC-OQAM systems.