6G 通訊技術是一個下世代的行動通訊技術，其提供比現今 5G 的速度、低延遲、高頻譜效率、高傳輸能力，由於低地球軌道 (LEO) 衛星運行在地球軌道上，可以避免如地面通訊般受到地形及地理位置的情況，此外，由於低軌衛星的運行速度非常快，通訊品質會受到都卜勒效應的影響，因此使用波束成形(Beamforming) 技術進行波束追蹤可以有效的應對。但隨著地面用戶數及波束數量的增加，地面下鏈多用戶間訊號干擾問題日漸嚴重，因此本篇論文針對低軌衛星和地面用戶間的通訊環境進行設計及建模，藉由分析單衛星及多衛星兩種不同狀況下的分佈機率，改善波束控制係數及策略。因此，吾人提出一種基於資訊幾何優化演算法 (IGO) 的 Actor-Critic 演算法，其方法是將 Actor 網路以 IGO 演算法替換，藉此以高斯分佈作為機率分布，予以優化，並且追求如何最大化總體傳輸速率 (Sum-Rate)。實驗數據結果顯示，吾人所提出的做法經過一定次數的迭代，兩種狀況均可以趨於穩定並且收斂。;6G communication technology, as a next-generation mobile communication technology, offers higher speeds, lower latency, greater spectral efficiency, and higher throughput compared to the current 5G. Low-Earth-Orbit (LEO) satellites, operating in Earth’s orbit, can overcome the limitations of terrestrial communications, such as constraints imposed by terrain and geographical locations. However, due to the extremely high operational velocity of LEO satellites, communication quality is significantly impacted by the Doppler effect. Beamforming, specifically beam tracking, is employed to effectively compensate for this challenge. Nevertheless, as the number of ground users and beams increases, downlink multi-user interference (MUI) becomes an increasingly severe problem. This thesis, therefore, designs and models the communication environment between LEO satellites and ground users. By analyzing probability distributions under both single-satellite and multi-satellite scenarios, we aim to improve beam control coefficients and strategies.
