SIMO/MISO MSE-Duality for Multi-User FBMC with Highly Frequency Selective Channels

Filter Bank based Multicarrier (FBMC) with Offset-QAM (O-QAM) modulation is one of the strong candidates for the physical layer of 5-th generation mobile communication systems. The combination of FBMC/OQAM with multiple antennas in a multi-user scheme poses some challenges towards the design of equalizers and precoders due to the frequency overlapping of the sub-carriers, especially in environments with highly frequency selective channels. In this work we first calculate a fractionally spaced Minimum Mean Square Error (MMSE)-based equalizer design to accommodate multi-user (MU) Single Input Multiple Output (SIMO)-FBMC. Then, we apply the Mean Square Error (MSE)-duality to calculate the corresponding precoders for MU Multiple Input Single Output (MISO)-FBMC. Furthermore, we present four possibilities for the power allocation between users and sub-carriers. We finally show the performance superiority of the new method compared to a recently proposed method.