  Terahertz spectrum is being researched upon to provide ultra-high throughput
radio links for indoor applications, e.g., virtual reality (VR), etc. as well
as outdoor applications, e.g., backhaul links, etc. This paper investigates a
monopulse-based beam tracking approach for limited mobility users relying on
sparse massive multiple input multiple output (MIMO) wireless channels. Owing
to the sparsity, beamforming is realized using digitally-controlled radio
frequency (RF) / intermediate-frequency (IF) phase shifters with constant
amplitude constraint for transmit power compliance. A monopulse-based beam
tracking technique, using received signal strength indi-cation (RSSI) is
adopted to avoid feedback overheads for obvious reasons of efficacy and
resource savings. The Matlab implementation of the beam tracking algorithm is
also reported. This Matlab implementation has been kept as general purpose as
possible using functions wherein the channel, beamforming codebooks, monopulse
comparator, etc. can easily be updated for specific requirements and with
minimum code amendments.
