On the Performance of Alamouti Scheme in 2 × 2 MIMO-FBMC Systems

Inhalt:
Currently, filterbank multicarrier (FBMC) modulation scheme is the subject of intensive research and on-going discussions on future technologies for the next generation (5G) of wireless communication systems. However, due to the intrinsic interference and omitted cyclic prefix (CP), it is challenging to handle MIMO channels in FBMC/OQAM systems. The classical Alamouti coding scheme cannot be easy applied to FBMC systems, as FBMC systems are only based on real orthogonality, whereas the Alamouti scheme requires the condition of complex orthogonality. In this paper, we extend the block-wise Alamouti scheme for a 2 × 2 MIMO-FBMC system. According to simulation results, the proposed approach applied for the FBMC system results in inferior BER performance comparing to the classical Alamouti scheme used in OFDM systems. However, by inserting an empty symbol as a guard interval (GI) between Alamouti blocks, we can achieve a BER performance closed to that in conventional OFDM systems. In addition, we show that in low SNR regime, the spectral efficiency achieved by the proposed coding scheme in the FBMC system is almost the same as that achieved by the OFDM reference system. In high SNR regime, the GI leads to the spectral efficiency loss.