Inband communication can be further divided into underlay and overlay categories. In
underlay D2D communication, cellular and D2D communica-
tions share the same radio resources. In contrast, D2D links
in overlay communication are given dedicated cellular resources.
Inband D2D can improve the spectrum efficiency of cellular
networks by reusing spectrum resources (i.e., underlay) or
allocating dedicated cellular resources to D2D users that
accommodates direct connection between the transmitter and
the receiver (i.e., overlay). The key disadvantage of inband
D2D is the interference caused by D2D users to cellular
communications and vice versa. This interference can be
mitigated by introducing high complexity resource allocation
methods, which increase the computational overhead of the
BS or D2D users