在本文中，由於單個可重構反射面板輔助的系統下只能提供有限的覆蓋率以及被動波束增益，因此我們在多個可重構反射面板輔助的多用戶系統中，嘗試透過解決用戶選擇以及波束分配的問題，以最大化系統效能。首先，藉由假設每個用戶只能被最多一個可重構反射面板所連線，我們可以將用戶及可重構反射面板的連線設計描述成一對一的配對問題，此時，基地台和可重構反射面板都使用半全向性的波束。接著，當完成用戶及可重構反射面板的連線，我們可以透過碼簿的波束訓練以設計聯合波束賦形。然而，當不同用戶選擇相同的基地台波束時，會發生波束碰撞導致整體系統效能下降。因此，我們需要讓不同用戶使用不同的基地台波束，使得在波束分配設計上，同樣可以被描述成一對一的配對問題。為了解決這兩個一對一配對問題，我們提出了匈牙利演算法以及延遲接受演算法。此外，我們提出了修改式延遲接受演算法處理此系統中產生的用戶間干擾以及可重構反射面板間的通道效應。模擬結果顯示當可重構反射面板的數量上升時，和做了不適當配對的用戶選擇和波束分配相比，我們提出的方法可以得到更高的系統效能。

In this work, due to the limited coverage and passive beamforming gain of a single-RIS-aided system, we consider the user selection problem and beam allocation problem to maximize the sum rate in multiple RISs-aided multi-user communication systems with channel information. First, by assuming each user can be connected to at most one RIS, we can formulate the problem as a one-to-one matching problem in user-RIS connection design, while the active beamforming at the base station (BS) and passive beamforming at the RIS are employed with the quasi-omnidirectional beam. Second, when the user-RIS connection is determined, we can further design the joint beamforming by codebook-based beam training. However, when the same BS beam is selected by different users, the beam conflict happens and decreases the sum rate. Therefore, we need to let the BS beam allocated for the different user should be different, resulting in a one-to-one matching in the beam allocation design. For solving these two one-to-one matching problems, we propose the Hungarian algorithm and deferred acceptance algorithm. Moreover, we propose the modified deferred acceptance algorithm to mitigate the inter-user-interference and inter-RIS-channel effect caused by this system. Simulation results show that compare to improper design of user-RIS connection and beam allocation, our proposed methods can achieve a higher sum rate as the number of RIS increases.

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