On Maximum Likelihood MIMO detection in QAM-FBMC systems

Multi-carrier modulation and especially CP-OFDM is widely used nowadays in several radio communications. However, FBMC is a potential alternative to CP-OFDM since it does not require cyclic prefix, and thus, it has a higher spectral efficiency. One of the characteristics of FBMC is that the received data are accompanied by a two dimensional inter-symbol interference term (2D ISI), which complicates MIMO techniques when combined with optimum detection. In this paper we consider the association of FBMC with the multiple-input multiple-output (MIMO) technique focusing on the spatial data multiplexing (SDM), and we investigate the use of Maximum Likelihood (ML) detection. We propose modified FBMC schemes based on inserting null data among QAM symbols to reduce, in this way, the overlapping of the symbols.