A QAM-FBMC Space-Time Block Code System with Linear Equalizers

New waveform design is one of the prominent 5G research directions which aims to increase spectrum efficiency and replace conventional cyclic prefixed orthogonal frequency division multiplexing (CP-OFDM) in 4G LTE systems. In particular, filter bank multi-carrier system (FBMC) is recognized as a promising post-OFDM candidate. Like other candidates, it sacrifices subcarrier orthogonality for improved spectrum confinement. In this paper, we show that a QAM based FBMC (QAM-FBMC) space-time block code (STBC) system can achieve close to CP-OFDM performance with a linear receiver only, settling the conventional perception of the necessity of non-linear equalizers in FBMC to support multiple-input multiple-output. The contribution of this paper is two-fold: (1) in terms of complexity and error rates performance our proposed QAM-FBMC system outperforms conventional OQAM-FBMC scheme; (2) a performance lower bound is shown numerically that QAM-FBMC attains close to CP-OFDM error rates.