中文摘要：

为了在全球覆盖的低地球轨道（ low earth orbit,LEO）卫星通信网络下,获得较小开销的组播树,而非仅仅是降低树开销或最小传输时延,提出一种面向LEO卫星通信网络的基于时间尺度的多度量负载均衡组播路由算法（ load balancing multicasting algorithm based on timescales for LEO satellite network,LBMT）,通过获取星间链路（ inter-satellite links, ISL）的状态信息并通过设计的评价链路状态“比对开销”,建立较小“比对开销”组播树。已提出的面向LEO卫星网路的组播路由算法通常目标为最小化组播树的树开销或传输时延,然而LEO卫星网络的全网流量并非均匀分布,已提出的组播算法通常无法主动避让繁忙链路,在高负载情况下导致网络状况恶化。仿真结果表明：算法能在高负载状态下降低数据丢失率,而仅仅微小增加了传输时延。 LBMT算法建立的组播树能有效避让繁忙链路并选择位于不发达地区上空的空闲链路,充分利用网络的空闲链路,使网络流量更加均衡。

英文摘要：

The purpose of this paper is aiming to build a low cost multicasting tree on a global coverage LEO satellite communication network. In this paper, the authors proposed a load balancing multicasting algorithm based on timescales for LEO satellite network （ LBMT） . LBMT collect the occupying state and calculate comparison cost of corresponding link and aiming to minimize the comparison cost rather than cost or delay of the tree. Several proposed multicasting algorithms aim for minimizing the delay or cost of multicast tree. However, the whole network traffic is not evenly distributed, multicast algorithms have been proposed usually deteriorate the network status under high load conditions because those algorithms often take the initiative to avoid the busy link. Simulation results shows that LBMT can decrease data loss rate under high traffic conditions with a little increase of transmission delay. Simulation results shows that LBMT can decrease data loss rate under high traffic conditions with a little increase of transmission delay. It can be concluded that the multicasting tree built by LBMT can efficiently avoid the busy ISLs and pick the idle ISLs above the developing region. The idle ISLs can be utilized by LBMT and the traffic of network is more balanced.