Maximum Likelihood Alamouti Receiver for Filter Bank Based Multicarrier Transmissions

Filter-bank based multicarrier (FBMC) transmission is an alternative to orthogonal frequency division multiplexing (OFDM) transmission, more spectrally efficient and more robust to asynchronisms than the latter. For these reasons, the FBMC waveform is a promising candidate for 5G mobile networks. Using offset quadrature amplitude (OQAM) symbols and a proper prototype filter, the FBMC waveform may become orthogonal for flat fading single-input single-output (SISO) channels. However, for frequency selective or multiple-input multipleoutput (MIMO) channels, the FBMC waveform is generally no longer orthogonal and inter-carrier interference (ICI) is present at reception. This ICI makes difficult the combination of FBMC waveforms with some MIMO schemes such as the Alamouti scheme in particular. In this context, the purpose of this paper is to introduce a new Alamouti receiver for the detection of the OQAM symbols transmitted by a FBMC waveform. This receiver is based on the maximum likelihood (ML) joint detection of the symbols transmitted by both the subcarrier of interest and its two adjacent subcarriers. Challenges for the receiver implementation are discussed jointly with sub-optimal alternatives to decrease the complexity.