5G	Fifth generation of cellular networks
EH	Energy harvesting
RF	Radio frequency
SWIPT	Simultaneous wireless information and power transfer
PLC	Power line communication
SG	Smart grids
IoT	Internet of Things
HWP	Hybrid wireless and power line communication
EE	Energy efficiency
SE	Spectrum efficiency
PT	Power transmission
PS	Power splitting
PSR	Power splitting-based relaying
TSR	Time splitting-based relaying
(O)DF	(Opportunistic) decode-and-forward
(O)AF	(Opportunistic) amplify-and-forward
ODF-AF	Opportunistic DF-AF
HD	Half-duplex
FD	Full-duplex
RS	Relay selection
SDP	Signal decision processor
SNR	Signal-to-noise ratio
CSI	Channel state information
AWGN	Additive white Gaussian noise
i.i.d.	independently and identically distributed
PDF	Probability density function
CDF	Cumulative distribution function
$\mathcal{OP}$	Outage probability
$ST\mathcal{P}$	Successful transmission probability
ACK	Acknowledgement signal
RV	Random variable
TDMA	Time division multiple access
SC	Selection combining
S	The source node
D	The destination node
$R_i$	The i-th relay of K relays, ($1\le i\le K$)
X, Y, Z	The channel coefficients of S–$R_i$, $R_i$–D, S–D links
${\left|X\right|}^2$, ${\left|Y\right|}^2$ and ${\left|Z\right|}^2$	The i.i.d. log-normal RVs with $LN\left(2{\omega }_X,4{\Omega }_X^2\right)$, $LN\left(2{\omega }_Y,4{\Omega }_Y^2\right)$ and $LN\left(2{\omega }_Z,4{\Omega }_Z^2\right)$
${\omega }_j$, ${\Omega }_j^2$	The mean and the standard deviation of $10{log}_{10}\left(j\right),j\in \{X;Y;Z\}$
$d_X$, $d_Y$, $d_Z$	The S–$R_i$, $R_i$–D, S–D distances
$P_S$	The power of S
$P_{R_i}$	The energy of i-th R
$n_j$	Additive white Gaussian noise (AWGN), ($j\in \left\{r_k,d\right\}$)
$N_0$	The zero mean and variance at the i-th R and D
${\chi }_i$	The decoding state of ODF-AF $R_i$, $i\in 1,\cdots ,K$