Delay-Outage Analysis of Multi-LEO Satellites Communication System

In this work, we investigate LEO satellite communication with relaying under Nakagami-m fading channels, enabling the terrestrial source to transmit packets to the terrestrial destination via the LEO satellite constellation. Two scenarios are applied in this work, i.e., opportunistic selection of the satellite relay and maximum ratio combining to combine signals from multiple LEO satellites. Moreover, two different cases are considered: one with satellites serving as relays with caching, and another with satellites serving as relays without caching. Then, the proposed models are evaluated by analyzing the end-to-end delay-outage probability. Analytical formulas for the delay-outage probability are obtained for both cases, and simulation results are used to demonstrate the system's dependency on various parameters. Overall, the study compares the two cases and scenarios in terms of delay-outage probability and determines the most efficient scheme. It is shown that our multi-LEO satellite architecture has significant performance gain compared to the single satellite schemes. In addition, cache-aided schemes perform better than cache-free cases at the expense of a higher implementation cost and more complex channel knowledge requirements.