  High-frequency bands such as millimeter-wave and terahertz require narrow
beams due to path loss and shadowing. Beam alignment (BA) methods allow the
transceivers to adjust the directions of these beams efficiently by exploiting
the channel sparsity at high frequencies. This paper investigates BA for an
uplink scenario, where the channel between the user equipment (UE) and base
station (BS) consists of multiple paths. The BS wishes to localize the angle of
arrival of each of these paths with a given resolution using the least number
of time slots. At each time slot of the BA, the UE transmits a BA packet and
the BS uses hybrid beamforming to scan its angular region. To minimize the
expected BA duration, a group testing framework is devised, and the associated
novel analog and hybrid BA strategies are described. Simulation studies show
the performance improvement both in noiseless and realistic 5G mmWave BA
settings.
