  The growing demand for radio access networks (RANs) driven by advanced
wireless technology and the everincreasing mobile traffic, faces significant
energy consumption challenges that threaten sustainability. To address this, an
architecture referring to the vertical heterogeneous network (vHetNet) has
recently been proposed. Our study seeks to enhance network operations in terms
of energy efficiency and sustainability by examining a vHetNet configuration,
comprising a high altitude platform station (HAPS) acting as a super macro base
station (SMBS), along with a macro base station (MBS) and a set of small base
stations (SBSs) in a densely populated area.
