  A present challenge in wireless communications is the assurance of
ultra-reliable and low-latency communication (URLLC). While the reliability
aspect is well known to be improved by channel coding with long codewords, this
usually implies using interleavers, which introduce undesirable delay. Using
short codewords is a needed change to minimizing the decoding delay. This work
proposes the combination of a coding and decoding scheme to be used along with
spatial signal processing as a means to provide URLLC over a fading channel.
The paper advocates the use of random linear codes (RLCs) over a massive MIMO
(mMIMO) channel with standard zero-forcing detection and guessing random
additive noise decoding (GRAND). The performance of several schemes is assessed
over a mMIMO flat fading channel. The proposed scheme greatly outperforms the
equivalent scheme using 5G's polar encoding and decoding for signal-to-noise
ratios (SNR) of interest. While the complexity of the polar code is constant at
all SNRs, using RLCs with GRAND achieves much faster decoding times for most of
the SNR range, further reducing latency.
