Non-Orthogonal Multiple Access in Large-Scale Heterogeneous Networks
Non-Orthogonal Multiple Access in Large-Scale Heterogeneous Networks
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DOI：
10.1109/jsac.2017.2726718
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发表时间：
2017-12-01
影响因子：
16.4
通讯作者：
McCann, Julie A.
中科院分区：
文献类型：
--
作者：
Liu, Yuanwei;Qin, Zhijin;McCann, Julie A.
本文探讨了非正交多址(NOMA)技术在K层混合异构网(HetNets)中的应用。提出了一种在小小区采用NOMA，在宏小区采用海量多输入多输出(MIMO)的新传输架构。为了最大化移动用户的有偏平均接收功率，提出了一种基于NOMA和海量MIMO的用户关联方案。为了评估该框架的性能，我们首先推导了NOMA增强型小小区覆盖概率的解析表达式。然后，我们通过推导NOMA增强型小蜂窝小区的精确解析表达式和大规模MIMO支持的宏蜂窝小区的易于处理的下界来检验整个网络的频谱效率。最后，我们研究了混合HetNets的能量效率。研究结果表明：1)NOMA增强型小小区的覆盖概率在很大程度上受两个NOMA用户的目标发射速率和功率分担系数的影响；2)大量支持MIMO的宏小区能够通过增加天线数来显著提高频谱效率；3)密集部署NOMA增强型小蜂窝基站可以显著提高整个网络的能量效率；4)与基于正交多址接入的HetNet相比，所提出的NOMA增强型HetNet传输方案具有更好的性能。
In this paper, the potential benefits of applying non-orthogonal multiple access (NOMA) technique in K-tier hybrid heterogeneous networks (HetNets) is explored. A promising new transmission framework is proposed, in which NOMA is adopted in small cells and massive multiple-input multiple-output (MIMO) is employed in macro cells. For maximizing the biased average received power for mobile users, a NOMA and massive MIMO based user association scheme is developed. To evaluate the performance of the proposed framework, we first derive the analytical expressions for the coverage probability of NOMA enhanced small cells. We then examine the spectrum efficiency of the whole network by deriving exact analytical expressions for NOMA enhanced small cells and a tractable lower bound for massive MIMO enabled macro cells. Finally, we investigate the energy efficiency of the hybrid HetNets. Our results demonstrate that: 1) the coverage probability of NOMA enhanced small cells is affected to a large extent by the targeted transmit rates and power sharing coefficients of two NOMA users; 2) massive MIMO enabled macro cells are capable of significantly enhancing the spectrum efficiency by increasing the number of antennas; 3) the energy efficiency of the whole network can be greatly improved by densely deploying NOMA enhanced small cell base stations; and 4) the proposed NOMA enhanced HetNets transmission scheme has superior performance compared with the orthogonal multiple access-based HetNets.