  In this paper, we consider a heterogeneous 5G cellular architecture that
separates the outdoor and indoor scenarios and in particular study the
trade-off between the spectrum efficiency (SE), energy efficiency (EE), economy
efficiency (ECE). Mathematical expressions for the system capacity, EE, SE, and
ECE respectively are derived using a proposed realistic power consumption
model. The comparison of system performance in terms of SE, EE, and ECE,
results in the observation that the proposed network architecture, which
separates the outdoor and indoor scenarios, offers a promising solution for
future communication systems that have strict requirements on the data rate and
efficiency.
