本篇論文中，討論在毫米波頻段下多用戶多輸入多輸出(Multi-User Multi-input Multi-Output, MU-MIMO)的天線系統使用混合式預編碼及混合式結合器來提升用戶的頻譜使用效率。由於基地台及使用者使用大規模天線陣列，傳統的預編碼上是需要非常大量的射頻(Radio Frequency, RF)電路元件，不僅硬體成本高而且佔空間，混合式預編碼可以透過降低射頻電路元件的數量，達到降低成本與減少空間。本篇論文提出的混合式預編碼及結合器可以同時間對每一個使用者傳輸多筆資料串流，預編碼及結合器由類比及數位二部分所組成，類比預編碼與結合器的設計為了降低運算複雜度與降低回授消耗，同時利用碼本與奇異值分解來達成目標。數位預編碼與結合器的設計則是使用區塊對角化來消除使用者之間的干擾，與最小均方誤差法來還原訊號。從本篇論文的模擬結果可以看出本篇所提出的方法不但可以減少回授消耗也可以提升其表現，也證實了本篇提出的方法能有效降低系統所需要的射頻電路元件數量，並且達到一定的傳輸率。

In this paper, we focus on the millimeter-wave (Mmwave) multi-user multiple-input-multiple-output (MU-MIMO) downlink systems and propose a hybrid precoding and combining design to improve the system spectrum efficiency. Consider that the base station (BS) and mobile stations (MSs) are equipped with large-scale antenna array. In this case, the conventional fully-digital precoding requires a large number of radio frequency circuits, which demands high cost and huge hardware space. The design of hybrid precoding can lower both cost and space by reducing the number of RF circuit components. In this paper, we focus on the multi-user beamforming case in which the BS transmits multiple data streams to each MS at the same time. The design proposed hybrid precoding and combining algorithm is accomplished in two stage. In the first stage, the analog precoder at the BS and the analog combiners at the MSs are jointly designed based on finite beamforming codebook and singular value decomposition(SVD) of the effective channel matrices, respectively, in order to maximize the received signal strength, neglecting the inter-user interference. In the second stage, the digital precoder and digital combiners are designed respectively based on block diagonalization(BD) and minimum mean square error(MMSE) criteria to eliminate the inter-user interference. From the simulation results, it shows that the proposed method can not only reduced feedback overhead but also increased the achievable rate with reduce the number of RF components.

口試委員審定書 i
致謝 ii
中文摘要 iii
ABSTRACT iv
目錄 v
圖次 vii
表次 viii
第一章 緒論 1
第二章 文獻探討 5
第三章 系統架構 12
3.1 多用戶毫米波多輸入多輸出混合式預編碼系統 12
3.2 毫米波通道模型 16
第四章 混合式預編碼及結合器設計 18
4.1 架構最佳化問題 18
4.2 傳送端類比預編碼設計 19
4.3 接收端類比結合器設計 21
4.4 傳送端數位預編碼設計 23
4.5 接收端數位結合器矩陣 25
第五章 模擬結果 27
第六章 結論 38
參考文獻 39

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