SDMA for FBMC with block diagonalization

This paper deals with the design of MIMO pre-coding and decoding matrices for the filter bank multicarrier (FBMC) modulation. With the aim of increasing the system throughput we focus on the downlink of a multi-user communication system, where users share the same time slots and frequency resources. In this sense, we revisit the block diagonalization (BD) technique since it provides a good trade-off between complexity and performance. Based on the BD concept, we have formulated a new set of conditions that achieve interference-free data multiplexing in the FBMC context. In addition, we have carried out a theoretical analysis that reveals under what conditions MIMO-FBMC shows superior performance than MIMO-OFDM systems. Simulations results demonstrate that in the cases of study, the proposed solution slightly outperforms the classical BD technique, which can be combined with either OFDM or FBMC systems, in terms of bit error rate.