  Next-generation wireless networks require massive connectivity and ubiquitous
coverage, for which non-terrestrial networks (NTNs) are a promising enabler.
However, NTNs, especially non-geostationary satellites bring about challenges
such as increased handovers (HOs) due to the moving coverage area of the
satellite on the ground. Accordingly, in this work, we compare the conventional
measurement-based HO triggering mechanism with other alternatives such as
distance, elevation angle, and timer-based methods in terms of the numbers of
HOs, ping-pong HOs, and radio link failures. The system-level simulations,
carried out in accordance with the 3GPP model, show that the measurement-based
approach can outperform the other alternatives provided that appropriate values
of hysteresis/offset margins and time-to-trigger parameters are used. Moreover,
future directions regarding this work are also provided at the end.
