A Trace-Time Framework for Prediction of Elevation Angle Over Land Mobile LEO Satellites Networks

Abstract

Elevation angle is one of the most significant parameters of land mobile satellite channels, subject to rapid variations in the case of Low Earth Orbit (LEO) satellite systems. In this paper a novel trace-based framework is proposed and analyzed which is capable of predicting elevation angle as a function of time during satellite visibility window. Tracetime based modeling makes the framework practical for real-time evaluation of elevation angle and its alteration incurred by communication links in LEO satellite systems. The proposed method is particularly suitable for development of communication channel models and services in mobile LEO satellite networks where path variability is of great importance.

A simple real-time handover management in the mobile satellite communication networks

“…The detailed system parameters of both satellite networks are shown in Table I. We use the same simulation package as that in [2] and the 30 terminals are scattered randomly on the earth with latitudes between 0 ∘ and 90 ∘ . The outcomes of the simulation scenario are used to validate the proposed handover algorithm.…”

“…1, the sub-satellite point of satellite 1 can be denoted by ( , ) while the location of the user is represented by ( , ). From [2], it is easy to know that if the user could obtain a series of the sub-satellite points in the form of longitude and latitude, the user could calculate the trace angle using the following equations:…”

“…This is a plausible assumption because hand-held devices equipped with GPS are prevalent nowadays. Let and denote the latitude and longitude of the user, then the user could obtain its rough trace angle using equations (2) and (3) based on the information extracted from the signals. Thus with equation (1), the user could learn the coverage time , corresponding to the ℎ satellite.…”

“…From end-users' point of view, the interruption of the ongoing connection is more undesirable than the blocking of a newly initiated call, we thus propose a simple and real-time handover management to minimize the satellite handover number, thus reducing the call drop probability. The proposed algorithm is based on the results derived in [2] for circular orbit LEO satellites. The trace angle is the key definition proposed in [2] and is closely related to the coverage time and the elevation angle dynamics between the users and the satellites.…”

“…The proposed algorithm is based on the results derived in [2] for circular orbit LEO satellites. The trace angle is the key definition proposed in [2] and is closely related to the coverage time and the elevation angle dynamics between the users and the satellites. With the help of the current GPS infrastructure and the hand-held devices equipped with GPS function, the users could readily obtain the trace angle.…”