Reconfigurable Antenna Multiple Access for 5G mmWave Systems
Reconfigurable Antenna Multiple Access for 5G mmWave Systems
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DOI：
10.1109/iccw.2018.8403609
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发表时间：
2018-03
期刊：
影响因子：
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通讯作者：
Mojtaba Ahmadi Almasi;H. Mehrpouyan;D. Matolak;Cunhua Pan;M. Elkashlan
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文献类型：
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作者：
Mojtaba Ahmadi Almasi;H. Mehrpouyan;D. Matolak;Cunhua Pan;M. Elkashlan
本文旨在基于最近提出的毫米波可重构天线结构实现一种新的多址接入技术。为此，我们首先证明了现有的可重构天线系统与著名的非正交多址（NOMA）技术的集成，由于可重构天线中不可避免的功率划分，导致求和速率显著下降。为了规避这一基本限制，提出了一种新的多址技术。该技术被称为可重构天线多址（RAMA），它在同一时间/频率/编码下只传输每个用户预定的信号，这使得RAMA成为一种用户间无干扰的技术。考虑了两种不同的情况，即具有部分和完整通道状态信息（CSI）的RAMA。在第一种情况下，不需要CSI，只使用特定用户的到达方向。我们的分析结果表明，对于部分CSI和对称信道，RAMA在求和速率方面优于NOMA。此外，分析结果表明，当分配给体验到较好信道质量的用户较少的功率时，非对称信道的RAMA比NOMA获得更好的和速率。在第二种情况下，具有完整CSI的RAMA为每个用户分配最佳功率，与对称和非对称信道相比，这导致更高的可实现速率。数值计算证实了分析结果。
This paper aims to realize a new multiple access technique based on recently proposed millimeter- wave reconfigurable antenna architectures. To this end, first we show that integration of the existing reconfigurable antenna systems with the well-known non-orthogonal multiple access (NOMA) technique causes a significant degradation in sum rate due to the inevitable power division in reconfigurable antennas. To circumvent this fundamental limit, a new multiple access technique is proposed. The technique which is called reconfigurable antenna multiple access (RAMA) transmits only each user's intended signal at the same time/frequency/code, which makes RAMA an inter-user interference-free technique. Two different cases are considered, i.e., RAMA with partial and full channel state information (CSI). In the first case, CSI is not required and only the direction of arrival for a specific user is used. Our analytical results indicate that with partial CSI and for symmetric channels, RAMA outperforms NOMA in terms of sum rate. Further, the analytical result indicates that RAMA for asymmetric channels achieves better sum rate than NOMA when less power is assigned to users that experience better channel quality. In the second case, RAMA with full CSI allocates optimal power to each user which leads to higher achievable rates compared to NOMA for both symmetric and asymmetric channels. The numerical computations demonstrate the analytical findings.