本篇論文提出了一個多載波非正交多重接取下行系統的資源分配技術，該系統包含一個基地台、N個載波和K位使用者，每個載波由兩個使用者共享進行非正交多重接取技術傳輸，此方法考慮使用者選擇、載波分配以及功率分配，在任意比例的公平性限制下，以達到最大化系統傳送容量。首先，在使用者選擇方面，是根據每位使用者的已擁有容量與其公平性之比值，將比值最小的兩個使用者配成一組進行非正交傳輸，接著，該組的兩位使用者的功率分配將根據不同情況有不同的計算最佳功率分配方式，並利用已算出的最佳功率分配，找尋一個載波可以最大化該組的傳送容量，上述步驟將一直重複執行直到所有子載波都分配完畢。模擬結果展示了所提出的低複雜度方法可以提供比正交系統還要好的傳送容量表現，也比考慮最大化最小的使用者傳送容量的方法更有彈性，並且能達到系統預先給定的公平性。

This thesis presents a resource allocation scheme for a downlink N-carrier non-orthogonal multiple access (NOMA) system with a base station serving K users, where each subcarrier is normally shared by two users for NOMA transmission. The scheme is derived from consideration of user selection, subcarrier allocation, and power allocation to maximize the system capacity under an arbitrary proportional user fairness constraint. The user selection is first performed according to the achieved capacity-to-fairness factor ratio of each user, where the two users with the smallest ratios are paired together for NOMA transmission on a subcarrier. The NOMA power allocation factor for the pair of users on a subcarrier is then determined by either maximizing the sum capacity on the subcarrier subject to an appropriate rate requirement of the user with a worse channel condition or maximizing the minimum user capacity on the subcarrier. With this, the sum capacity of the pair of users on each of available subcarriers can be further calculated, and the subcarrier with the maximum sum capacity is allocated to the pair of users for NOMA transmission. The above procedure is repeated until all the N subcarriers have been assigned to all the K users. It is shown that the resource allocation performance well satisfies the proportional user fairness constraint with low computational complexity of O(N^2+K^2). It is also demonstrated by simulation results that the proposed scheme offers higher system capacity than the conventional orthogonal frequency division multiple access scheme and a previous related multiuser multicarrier NOMA work with two users sharing an identical fairness factor.

Abstract i
Contents ii
List of Figures iii
I. Introduction 1
II. System Model and Problem Formulation 3
A. System Model 3
B. Problem Formulation 5
III. Propsoed Resource Allocation Scheme 6
A. User Pairing 6
B. Joint Subcarrier and Power Allocation 7
IV. Simulation Results 9
A. Sum Capacity 10
B. Each User Capacity 13
C. Convergence Behavior 17
V. Conclusion 19
Appendix 19
References 21

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