FBMC-OQAM transceivers for wireless and optical fiber communications

Rottenberg, François [UCL]

How to communicate ? Human beings use the voice or gestures to give shape to their ideas. In digital communications, a modulation scheme is used to give shape to bits of information, i.e., to convert zeros and ones into an analog waveform. The question of an ideal modulation scheme is discussed in this thesis and we study the one that seems the most promising to us. The orthogonal frequency division multiplexing (OFDM) modulation is the most popular multicarrier modulation scheme nowadays. The main advantage of OFDM is its simplicity. However, due to the rectangular pulse shaping of the Fast Fourier transform filters, OFDM systems exhibit very high frequency leakage and poor stopband attenuation. In the light of these limitations, the offset-QAM-based filterbank multicarrier (FBMC-OQAM) modulation has recently received increasing attention. Rather than using a rectangular pulse, FBMC-OQAM uses a pulse shape which is more spread out in time, which results in a much better frequency localization. This in turn translates into higher spectral efficiency and much more flexibility for spectrum allocation. The main objective of this thesis is to investigate the applicability of the FBMC-OQAM modulation for next generations of communication systems. More specifically, we focus on two main directions. The first direction studies advanced equalization algorithms for multiple-antenna wireless systems characterized by highly frequency and/or time selective channels. The second direction studies two main linear impairments in optical fiber systems, namely, phase noise and chromatic dispersion.