  In this paper, we design receivers for filter bank multicarrier-based
(FBMC-based) massive MIMO considering practical aspects such as channel
estimation and equalization. In particular, we propose a spectrally efficient
pilot structure and a channel estimation technique in the uplink to jointly
estimate all the users' channel impulse responses. We mathematically analyze
our proposed channel estimator and find the statistics of the channel
estimation errors. These statistics are incorporated into our proposed
equalizers to deal with the imperfect channel state information (CSI) effect.
We revisit the channel equalization problem for FBMC-based massive MIMO,
address the shortcomings of the existing equalizers in the literature, and make
them more applicable to practical scenarios. The proposed receiver in this
paper consists of two stages. In the first stage, a linear combining of the
received signals at the base station (BS) antennas provides a coarse channel
equalization and removes any multiuser interference. In the second stage, a per
subcarrier fractionally spaced equalizer (FSE) takes care of any residual
distortion of the channel for the user of interest. We propose an FSE design
based on the equivalent channel at the linear combiner output. This enables the
applicability of our proposed technique to small and/or distributed antenna
setups such as cell-free massive MIMO. Finally, the efficacy of the proposed
techniques is corroborated through numerical analysis.
