  This paper reports relative performance of decode-and-forward (DF) and
amplify-and-forward (AF) relaying in a multi-antenna cooperative cognitive
radio network (CCRN) that supports device-to-device (D2D) communications using
spectrum sharing technique in cellular network. In this work, cellular system
is considered as primary and internet of things devices (IoDs), engaged in D2D
communications, are considered to be secondary system. The devices access the
licensed spectrum by means of the cooperation in two-way primary
communications. Furthermore, IoDs are energized by harvesting the energy from
radio frequency (RF) signals, using simultaneous wireless information and power
transfer (SWIPT) protocol. Closed form expressions of outage probability for
both cellular and D2D communications are derived and the impact of various
design parameters for both AF and DF relaying techniques are studied. Based on
the simulation results, it is found that the proposed spectrum sharing
protocol, for both DF relaying and AF relaying schemes, outperform another
similar network architecture in terms of spectrum efficiency. It is also
observed that the performance of the proposed system using DF relaying is
better than AF relaying scheme in terms of energy efficiency at same transmit
power.
