功率域非正交多重接取(non-orthogonal multiple access; NOMA)是一相當具有潛力應用於未來無線通訊的傳輸技術。在本論文中，我們探討包含兩個使用者之多輸入多輸出(multiple-input multiple output; MIMO)NOMA上行系統的使用者功率分配問題，其中強使用者具有較大的通道增益，而弱使用者則具有較小的通道增益；在採用正交相移鍵控(quadrature phase shift keying; QPSK)調變以及線性最小均方誤差偵測的情況下，我們首先推導出兩個使用者的位元錯誤率(bit error rate; BER)表示式，然後依據所推導的結果並使用最小平方曲線擬合方法設計一個功率分配閉合解，以最小化弱使用者的BER效能。電腦模擬結果顯示，與傳統的等功率分配作法相比，所設計之上行MIMO-NOMA功率分配方案不僅可提供較佳的使用者平均BER效能，而且可強化使用者之間的效能公平性。

Power-domain non-orthogonal multiple access (NOMA) is considered one of the promising transmission techniques for future wireless communications. In this thesis, we investigate users’ power allocation issues for a two-user uplink multiple-input multiple-output (MIMO) NOMA system, which includes a strong user with a larger channel gain and a weak user with a smaller channel gain. Using QPSK modulation and linear minimum mean-squared error detection, we first derive bit error rate (BER) expressions for both users, and then use the results along with the least-squares curve fitting method to design a closed-form power allocation solution for minimizing the weak user’s BER. Computer simulation results demonstrate that, as compared with the conventional equal power allocation method, the proposed scheme for uplink MIMO-NOMA transmission not only provides much better users’ average BER performance but also enhances performance fairness between the two users.

Abstract
Contents
List of Figures
I. Introduction---------------------------------------------------1
II. System Model--------------------------------------------------4
III. BER Analysis-------------------------------------------------6
A.Review of BER Expressions for an Uplink SISO-NOMA System-------6
B.BER Expressions for the Two-User Uplink MIMO-NOMA System-------8
IV. A Power Allocation Method for the Uplink MIMO-NOMA System----13
V. Simulation Results--------------------------------------------15
VI. Conclusion---------------------------------------------------23
References-------------------------------------------------------24

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