Core-based shared trees in LEO satellitte networks

The satellite network is suitable to provide multicast services with broadcast capability, especially for the low earth orbit (LEO) satellite network due to its short round-trip delays. A new multicast routing algorithm called dynamic approximate center tree (DACT) is proposed specifically for LEO satellite networks in this paper. And a simple core placement method is presented to find the root for every multicast tree. Since processing packets in intermediate satellites consumes much time, paths from the core to other member nodes of a group are built using multicast routing algorithm (MRA) to reduce the number of branches, which tries to merge the links wherever possible. The DACT algorithm can be applied to many-to-many communications in LEO satellite networks. Also it supports dynamic group membership. Delay and tree cost performances of DACT algorithm are compared with those of other two schemes, whose core placement methods are named random core and diameter core (DC) respectively. Simulation results show that DACT produces the lowest mean delay and tree cost among the three methods.