針對波束域下使用多使用者多輸入多輸出系統及非正交多重接取系統之用戶分群及波束選擇演算法

多用戶多重輸入多重輸出(Multi-user Multiple-input multiple-output, MU-MIMO)、非正交多重接取(Non-orthogonal multiple access, NOMA)及波束形成(Beamforming)是當前被提出用以提升無線通訊系統效能的重要技術。本論文主要針對下鏈波束形成系統中，基於MU-MIMO及NOMA之用戶群集和波束選擇演算法之最佳化設計進行探討。第一部分針對基於MU-MIMO及NOMA之下鏈波束成形系統進行介紹。第二部份將提出兩個預編碼方法:一是於MU-MIMO群組中進行強制零預編碼及於NOMA群組中進行共軛預編碼;另一則是於MU-MIMO群組中進行強制零預編碼及於NOMA群組間進行強制零預編碼。第三部份我們將介紹針對本系統功率分配之設計，主要為基於平均群組功率分配方案下找到每個群組之預功率分配，在基於此預功率分配求得NOMA之功率分配係數。第四部份則會介紹五種不同之用戶群及波束選擇演算法。最後，我們將針對前述五種演算法之平均和率(Sum rate)、公平性(Fairness)及最弱用戶(Weakest user)之容量(Capacity)進行比較。

關鍵字

波束形成；非正交多重接取；多用戶多重輸入多重輸出；用戶分群；波束選擇

並列摘要

Multi-user multiple-input multiple-output (MU-MIMO), non-orthogonal multiple access (NOMA) and beamforming technologies have been proposed as key features to enhance the performance of modern wireless communication systems. In this paper, we aim to find the optimize design of the user grouping and beam selection algorithm for the downlink beamforming system. The downlink beamforming system with MU-MIMO and NOMA is considered. Two precoding methods are proposed. The first one is to perform intra-group zero-forcing precoding for MU-MIMO groups and conjugate precoding for NOMA groups. The second one is to perform intra-group zero-forcing precoding for MU-MIMO groups and zero-forcing precoding between all NOMA groups. In addition, we will propose the power allocation design base on proportional group power allocation scheme and find the sub optimal NOMA power allocation factor. Finally, five user grouping and beam selection algorithms are proposed. Simulations are conducted to compare the average sum rate, fairness, and weakest user capacity for the proposed algorithms.

並列關鍵字

User grouping ； Beamforming ； NOMA ； MU-MIMO ； Beam selection

參考文獻

[1] B. Mielczarek and W. Krzymien. Adaptive CSI prediction in linear multi-user MIMO systems. In IEEE 70th Veh. Tech. Conf., 2009.

[2] Q. Spencer, A. L. Swindlehurst, and M. Haardt, "Zero-forcing methods for downlink spatial multiplexing in multiuser MIMO channels", IEEE Trans. Signal Process., vol. 52, no. 2, pp. 461-471, 2004.

[3] F. Khalid and J. Speidel, "Advances in MIMO techniques for mobile communications—A survey", Int. J. Commun., Netw. Syst. Sci., vol. 3, no. 3, pp. 213-252, 2010.

[4] M. Jiang and L. Hanzo, "Multiuser MIMO-OFDM for next-generation wireless systems", Proc. IEEE, vol. 95, no. 7, pp. 1430-1469, 2007.

[5] El-Khamy, S.E.; Moussa, K.H.; El-Sherif, A.A., “C5. Performance analysis of massive MIMO multiuser transmit beamforming techniques over generalized spatial channel model,” Radio Science Conference (NRSC), 2015 32nd National, pp.139-146, March, 2015.

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針對波束域下使用多使用者多輸入多輸出系統及非正交多重接取系統之用戶分群及波束選擇演算法

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