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 paper, we propose a low-complexity scheme for frequencydomain equalization with interleaved training sequences (FDEITS). Despite its low complexity, the FDE-ITS achieves the same phase noise tolerance and bit error rate (BER) performance against amplified spontaneous emission (ASE) noise as the phasecorrected 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 signalto- noise ratio (OSNR) 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.