利用衛星網路是一個新興的方式以提供無處不在的網路服務。 然而，衛
星的移動會使得傳統網路的路由策略無法直接應用在衛星網路中。 這篇論
文探討了在衛星網路中多播路由所面臨的挑戰，衛星的移動使地面使用者
的服務衛星隨著時間不斷改變。 當在衛星網路中執行多播時，服務衛星的
改變會產生大量的鏈路控制訊號。 最小化控制訊號負擔是一個 NP-困難問
題， 於是我們提出了一個基於動態規劃的演算法 DMTS 以在多項式時間的
複雜度下求得次佳解。 此外，我們提出了一個多播樹生成演算法 LMBBSP
以在不平衡的網路中避免鏈路壅塞。 模擬的結果顯示所提出的策略在鏈路
換手數量以及拒絕的請求數量比起比較基準都可以得到更好的結果。

Satellite networks are a promising way to provide ubiquitous accessibility of
network service. However, due to the mobility of satellites, the traditional routing
scheme cannot be adopted to the constellation directly. This thesis studies the challenge of multicast routing on satellite networks. The mobility of satellites makes
the serving satellites of ground users change with time. When performing a multicast on the constellation, the changing of serving satellites leads to a large amount
of link handover control messages. To minimize the control message overhead
is NP-hard. Therefore, a dynamic programming-based algorithm called Dynamic
Multicast Tree Selection (DMTS) is then proposed to find the sub-optimal result
with polynomial time complexity. DMTS reduces the link handovers of the dynamic multicast tree algorithms. Besides, we proposed a tree generation algorithm
called LMBBSP with DMTS to avoid link congestion in unbalanced network load.
The simulation results show that our proposed schemes outperform the baselines
in aspects of link handovers and request rejection rate.

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