Spectral Efficiency and Energy Efficiency of Bidirectional Distributed Antenna Systems With User Centric Virtual Cells
Spectral Efficiency and Energy Efficiency of Bidirectional Distributed Antenna Systems With User Centric Virtual Cells
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DOI：
10.1109/access.2018.2869134
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发表时间：
2018
期刊：
影响因子：
3.9
通讯作者：
Xingquan Li;Chunlong He;Ji-hong Zhang
中科院分区：
文献类型：
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作者：
Xingquan Li;Chunlong He;Ji-hong Zhang
在本文中，我们首先介绍了双向分布式天线系统（DAS），并利用选择算法，以用户为中心的虚拟小区到这个系统中。然后，我们讨论了不同的功率分配优化问题的干扰，在双向DAS与用户为中心的虚拟小区，分别。第一个目标问题是最大化双向DAS的频谱效率（SE），满足每个用户设备的最小SE和每个远程接入单元的最大发射功率的要求。首先，我们将这个非凸目标函数转换为凸函数的差（D.C.）问题，然后，我们得到的最优功率分配使用凹凸过程（CCCP）算法。第二个目标问题是在与第一个问题相同的约束下最大化双向DAS的能量效率（EE）。首先，利用分式规划理论将第二个问题转化为一个等价的目标函数，然后将其转化为一个DC问题，并利用CCCP算法求得最优解。在每一部分中，我们提出了相应的最优功率分配算法，并使用类似的方法来获得相同的优化问题的最优解的双向DAS与以用户为中心的虚拟小区。仿真结果表明了所提出的功率分配算法的有效性，并证明了SE和EE的双向DAS与以用户为中心的虚拟小区，这是远远优于双向DAS。
In this paper, we first introduce the bidirectional distributed antenna systems (DAS) and exploit the choosing algorithm to take user-centric virtual cells into this system. Then, we discuss different power allocation optimization problems with interferences in bidirectional DAS with and without user-centric virtual cells, respectively. The first objective problem is maximizing spectral efficiency (SE) of bidirectional DAS satisfying the requirements of the minimum SE of each user equipment and maximum transmit power of each remote access unit. First, we convert this non-convex objective function into a difference of convex functions (D.C.) problem, and then, we obtain the optimal power allocation by using the concave–convex procedure (CCCP) algorithm. The second objective problem is maximizing energy efficiency (EE) of bidirectional DAS under the same constraints as the first problem. First, we exploit fractional programming theory to transform the second problem into an equivalent objective function with subtractive form, and then convert it into a D.C. problem and obtain the optimal solutions by using the CCCP algorithm. In each part, we propose the corresponding optimal power allocation algorithm and also use a similar method to obtain optimal solutions of the same optimization problems in bidirectional DAS with user-centric virtual cells. Simulation results showed the effectiveness of the proposed power allocation algorithms and demonstrate the SE and EE of the bidirectional DAS with user-centric virtual cells which are much better than bidirectional DAS.