NB-IoT	Narrowband Internet of things
LEO	Low Earth Orbit
CE	Coverage Enhancement
RACH	Random Access Channel
NGSA-II	Non-dominated Sorting Genetic Algorithms-II
ISL	Inter-Satellite Link
D2D	Direct to Device
NTN	Non-terrestrial Network
MAC	Medium Access Control
RLC	Radio Link Control
PDCP	Packet Data Convergence Protocol
RRC	Radio Resource Control
DMRS	Demodulation Reference Signal
GNSSs	Global Navigation Satellite Systems
HARQ	Hybrid Automatic Repeat Request
SINR	Signal-to-Interference-plus-Noise Ratio
TA	Time Advance
RSRP	Reference Singal Receiving Power
PDF	Probability Distribution Function
LOS	Line of Sight
NLOS	Non-line of Sight
RAR	Random Access Response
RTD	Round Trip Delay
PSO	Particle Swarm Optimization
3GPP	3rd Generation Partnership Project