  In this letter, we propose a vector quantized-variational autoencoder
(VQ-VAE)-based feedback scheme for robust precoder design in multi-user
frequency division duplex (FDD) systems. We demonstrate how the VQ-VAE can be
tailored to specific propagation environments, focusing on systems with low
pilot overhead, which is crucial in massive multiple-input multiple-output
(MIMO). Extensive simulations with real-world measurement data show that our
proposed feedback scheme outperforms state-of-the-art autoencoder (AE)-based
compression schemes and conventional Discrete Fourier transform (DFT)
codebook-based schemes. These improvements enable the deployment of systems
with fewer feedback bits or pilots.
