為了提供5G行動通訊系統更高的資料量，巨量天線多重輸入多重輸出系統為最適合的選擇，而混和的架構有著較少的硬體成本和功率消耗的特性，與巨量天線多重輸入多重輸出系統搭配為目前熱門的研究議題。在5G行動通訊系統中，不同國家所操作的頻段會不同，且差距相當的大。而天線設計是為了該服務區域的操作頻段所配置的，在國際漫遊的情境下，若手機的天線操作於不符合設計之頻段的話，會造成波束的偏移及失真，導致傳輸效能下降。因此，本文將討論頻率差異對於系統容量的影響，並提出新的設計方法。首先，先展示了頻率差異對通道容量的影響，分類了四種情況，每一種情況需要的通道狀態資訊不同，分析在不同的情況下哪一種演算法較適合使用，進而再探討回饋頻率差異參數後的精準度問題。最後，結果顯示頻率差異的參數很重要，必須完美回饋頻率差異之參數，否則影響通道容量甚鉅，而我們提出的設計方法優於其他方法。

In order to provide a higher amount of data for 5G mobile communication systems, the best option is the massive multiple input multiple output (MIMO) system. The hybrid architecture has less hardware cost and power consumption, and is a popular research topic with massive multiple-input multiple-output systems. In 5G mobile systems, the frequency bands operated by different countries will be different, and the gap is quite large. In the case of international roaming, if the mobile phone operates in a frequency band that does not match the design, it will cause beam shift and distortion, resulting in degradation of transmission performance. Therefore, this paper will discuss the effects of frequency discrepancy on capacity and propose a new design method. First, the effects of frequency discrepancy on channel capacity are shown, and four scenarios are categorized, each of them requiring different channel state information, to analyze which algorithm is more suitable for different scenario, and then the problem of accuracy after feeding back the information of the frequency discrepancy is investigated. Finally, the results show that the information of the frequency discrepancy are important and must be perfectly feedback to the information of the frequency discrepancy, otherwise the impact on the capacity is significant and our proposed design method is better than other methods.

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