隨著5G行動通訊系統發展，協調同步軌道衛星 (Geosynchronous Equatorial Orbit，GEO) 和低軌道衛星 (Low Earth Orbit，LEO) 成為未來非地面網路 (Non-Terrestrial Networks，NTN) 無線通訊資源節約之方案。當共享頻譜資源之LEO以及GEO衛星服務之用戶設備 (User Equipment，UE) 數量增加，衛星之間的在線干擾 (in-line interference) 是需要解决之問題。衛星可以利用頻率複用 (frequency reuse) 中的圓極化 (circular polarization) 平面天線陣列形成多個互不干擾之波束 (multiple beams)。本研究考慮具有波束跳躍 (beam hopping) 現象之多波束LEO和GEO衛星，通過協調安排衛星網路之波束跳躍方案，最小化在線干擾並提升整體系統容量。 本研究針對地球移動波束 (earth moving beam) LEO網路，藉由統計LEO衛星系統之使用頻率，針對多波束之GEO提出八種不同下行無線動態頻譜共享資源分配機制，產生跳頻矩陣 (frequency hopping matrix)。多波束之GEO衛星與GEO 設備裝置根據該矩陣進行同步跳頻，可降低LEO與GEO之間在線干擾，達成提升整體衛星系統傳輸效能之目標。模擬評估所提出之機制對於系統容量、LEO與GEO內UE間存取資源之公平性，以及所有方案之時間成本，驗證從協調中獲得之優勢。根據模擬結果，本研究提出之貪婪方案之效能僅與最優方案差距0.51%，且具有更好之系統公平性及更少之時間消耗。;With the development of fifth generation mobile networks, coordinating the geosynchronous equatorial orbit (GEO) satellites and low earth orbit (LEO) satellites becomes a non-terrestrial network (NTN) solution for future radio communication which requires resource saving scheme. With the increasing number of user equipment (UEs) which are served in the footprints of LEO and GEO satellites simultaneously, in-line interference between these two satellites is an important issue need to be resolved especially when the spectrum resource is shared. A satellite could utilize circularly polarized planar antenna array and the frequency reuse technique to form multiple beams without inter-beam interference. This thesis considers multi-beam LEO and GEO satellites with beam hopping phenomenon to minimize in-line interference and improve the overall system capacity by coordinating beam hopping patterns of two satellite networks. This thesis proposes eight different downlink wireless dynamic spectrum sharing resource allocation schemes for multi-beam GEO to generate the frequency hopping matrix according to the frequency hopping pattern of earth-moving LEO satellite. Multi-beam GEO satellites and GEO user equipment perform synchronous frequency hopping according to this matrix, which can reduce the in-line interference between LEO and GEO, and achieve the goal of improving the capacity of overall satellite system. The proposed schemes are simulated and evaluated in terms of system capacity, fairness between LEO and GEO UEs, and time cost to verify the advantages obtained from coordination. Simulation results show that the system capacity of the proposed greedy scheme is only 0.51% worse than that of the optimal scheme, and also has better system fairness and less time consumption.
