Delay-bounded and minimal transmission broadcast in LEO satellite networks

Satellite systems have attracted much attention from academic and industrial communities in the past 20 years. There are many satellites that have been launched for all kinds of applications. Broadcast is a fundamental operation in satellite networks. It is frequently used for satellites self-organization, coordination and collaboration. The problem of our concern is, given an Low earth orbit (LEO) satellite network and a delay-bound, to find a broadcast schedule that delivers a message to all satellites within the delay-bound and the total number of transmissions is minimized. In this paper, we propose a broadcast routing and transmission scheduling algorithm for satellite networks. We first develop a space-time graph that models the dynamic connectivity of the satellite network as time progresses forward. The broadcast message is carried from one position to the other where it is forwarded to other recipients. A greedy algorithm with back-track search is designed to find the best transmitting nodes and the best transmission time in order to achieve the minimal number of transmissions subject to the constraint of delay-bound. Simulations have been conducted in the real LEO satellite constellations. Simulation results show good performance of our proposed scheme.