  The dynamic nature of indoor environments poses unique challenges for
next-generation millimeter-wave (mmwave) connectivity. These challenges arise
from blockages due to mobile obstacles, mm-wave signal scattering caused by
indoor surfaces, and imperfections in phased antenna arrays. Consequently,
traditional compressed sensing (CS) techniques for beam alignment become
ineffective in practice under such settings. This paper proposes a novel beam
alignment technique suited for mm-wave systems operating in indoor
environments. The proposed technique exploits the energy compaction property of
the discrete cosine transform to compressively sense and identify the strongest
cluster locations in the transform domain for robust beamforming. Experimental
results at 60 GHz demonstrate successful beam alignment with limited
measurements even in the presence of partial blockages during the beam training
phase.
