AF	Amplify-and-forward
AWGN	Additive white Gaussian noise
BEP	Bit error probability
BER	Bit error rate
CDF	Cumulative distribution function
CR	Cognitive radio
CSI	Channel state information
D	Destination
DF	Decode-and-forward
DH	Dual-hop
EH	Energy harvesting
ER	Energy receiver
FD	Full-duplex
IoT	Internet of Things
i.i.d	Independent and identically distributed
LoS	Line of sight
MIMO	Multiple-input multiple-output
NOMA	Non-orthogonal multiple access
OFDM	Orthogonal frequency-division multiplexing
PB	Power beacon
PDF	Probability distribution function
PS	Power-splitting
PT	Primary transmitter
R	Relay
RF	Radio frequency
r.v	Random variables
S	Source
SEP	Symbol error probability
ST	Secondary transmitter
SWIPT	Simultaneous wireless information and power transfer
TS	Time-switching
TW	Two-way
UAV	Unmanned aerial vehicle
WP	Wireless powered
WPC	Wireless-powered communication.