大规模MIMO系统能效问题研究
发布时间：2018-10-20 20:16
【摘要】：当今社会随着移动数据流量爆炸性增长以及频谱资源的短缺,大规模多输入多输出(MIMO)技术可以预见成为下一代移动通信系统的核心技术点,同时绿色通信也成为未来通信领域的焦点。本文主要研究大规模MIMO系统中的能效(EE)问题,具体研究内容如下:研究了基于Rayleigh信道分别在多小区和单小区情形下如何选择基站天线数目和发送功率,以最大化多用户大规模MIMO系统中的下行能效。与大多数以前的工作不同,我们使用更加实际的功耗模型,明确描述能效如何非线性地依赖于基站天线数目,终端用户数和发送功率,在具有完美信道状态信息(CSI)的迫零法(ZF)处理下导出用于最大化能效的参数解及其简单闭合表达式,最后通过数值分析得出了对应各参数的最优解,同时也证明了理论分析的正确性。我们对比了多小区和单小区这两种情形在某些相同条件下的结果,而且在单小区情形中,同时还比较了在ZF、最小均方误差(MMSE)和最大比传输/合并(MRT/MRC)这三种线性处理情形下系统能效与基站天线数的关系。研究了基于Nakagami衰落信道下大规模MIMO系统的下行能效,考虑了收发两端CSI均已知和发送端CSI未知仅接收端CSI已知这两种情形,并且分别利用了ZF和MMSE两种线性处理法进行分析对比。首先得到该系统的系统模型,该模型包括信道模型、一种新的电路功耗模型以及基于Nakagami信道的信号模型,然后基于这个系统模型得到系统能效的表达式,基于这个表达式我们可以分析能效的最优解,最后通过数值分析加以验证。研究了与前两章不同的小区结构下的分布式天线系统能效,并与基于该小区结构的集中式能效进行了对比。首先根据发送端和接收端天线数量的不同配置,在一种双重衰落信道下,得到分布式天线系统的能效近似表达式,并推导了各情况下的使能效最大的各参数的最优解的表达式,如最优的发送功率、基站天线数等。本章还基于Nakagami衰落信道研究了分布式大规模MIMO系统的能效。然后我们通过数值分析比较了各个情形下分布式和集中式的能效性能,以及分布式Nakagami信道下的能效,验证了两种情况下理论分析的准确性。最后联系现实,我们考虑到日常基站架设中下行通信中接收端(用户设备)天线数一般不会超过发送端(基站)天线数,因此可以得出分布式天线的能效一般来说比集中式天线更加突出,从而说明了分布式天线系统对于当今的研究热点绿色通信技术具有重要的研究意义。
[Abstract]:Nowadays, with the explosive growth of mobile data flow and the shortage of spectrum resources, the large-scale multi-input and multi-output (MIMO) technology can be predicted to become the core technology of the next generation mobile communication system. At the same time, green communication also becomes the focus of future communication field. In this paper, the problem of energy-efficient (EE) in large-scale MIMO systems is studied. The main contents are as follows: how to select the number of base station antennas and transmission power in multi-cell and single-cell cases based on Rayleigh channel is studied. In order to maximize the downlink energy efficiency in multi-user large-scale MIMO systems. Unlike most previous work, we use a more practical power model to explicitly describe how energy efficiency is nonlinear dependent on the number of base station antennas, the number of end users, and transmission power. The parameter solution and its simple closed expression for maximizing energy efficiency are derived under the Zero-forcing (ZF) process with perfect channel state information (CSI). Finally, the optimal solution for each parameter is obtained by numerical analysis. At the same time, it also proves the correctness of the theoretical analysis. We compare the results of multi-cell and single-cell under some same conditions, and in the case of single cell, The relationship between system energy efficiency and the number of base station antennas in the case of ZF, minimum mean square error (MMSE) and maximum ratio transmission / combination (MRT/MRC) is also compared. The downlink energy efficiency of large scale MIMO systems based on Nakagami fading channel is studied. Two cases are considered in which the CSI is known at both ends of the transmitter and receiver and only the CSI at the receiver is unknown at the sender and transmitter. Two linear processing methods, ZF and MMSE, are used to analyze and compare. First, the system model of the system is obtained, which includes the channel model, a new circuit power model and the signal model based on Nakagami channel, and then the expression of system energy efficiency is obtained based on the system model. Based on this expression, we can analyze the optimal solution of energy efficiency and verify it by numerical analysis. The energy efficiency of distributed antenna system under different cell structure from the previous two chapters is studied and compared with the centralized energy efficiency based on the cell structure. Firstly, according to the different configurations of antennas at the transmitter and receiver, the approximate expression of the energy efficiency of distributed antenna system is obtained in a dual fading channel, and the optimal solution of the parameters that make the maximum energy efficiency in each case is derived. Such as the optimal transmission power, base station antenna number and so on. This chapter also studies the energy efficiency of distributed large-scale MIMO systems based on Nakagami fading channels. Then we compare the distributed and centralized energy efficiency performance in each case and the energy efficiency in distributed Nakagami channel by numerical analysis, and verify the accuracy of the theoretical analysis in both cases. Finally, in connection with the reality, we consider that the number of receiving (user equipment) antennas in the downlink communication during the daily base station erection generally does not exceed the number of transmitting (base station) antennas. Therefore, it can be concluded that the energy efficiency of distributed antenna is generally more prominent than that of centralized antenna, which shows that distributed antenna system is of great significance to the research of green communication technology.
【学位授予单位】：南京邮电大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN919.3
本文编号：2284280
[Abstract]:Nowadays, with the explosive growth of mobile data flow and the shortage of spectrum resources, the large-scale multi-input and multi-output (MIMO) technology can be predicted to become the core technology of the next generation mobile communication system. At the same time, green communication also becomes the focus of future communication field. In this paper, the problem of energy-efficient (EE) in large-scale MIMO systems is studied. The main contents are as follows: how to select the number of base station antennas and transmission power in multi-cell and single-cell cases based on Rayleigh channel is studied. In order to maximize the downlink energy efficiency in multi-user large-scale MIMO systems. Unlike most previous work, we use a more practical power model to explicitly describe how energy efficiency is nonlinear dependent on the number of base station antennas, the number of end users, and transmission power. The parameter solution and its simple closed expression for maximizing energy efficiency are derived under the Zero-forcing (ZF) process with perfect channel state information (CSI). Finally, the optimal solution for each parameter is obtained by numerical analysis. At the same time, it also proves the correctness of the theoretical analysis. We compare the results of multi-cell and single-cell under some same conditions, and in the case of single cell, The relationship between system energy efficiency and the number of base station antennas in the case of ZF, minimum mean square error (MMSE) and maximum ratio transmission / combination (MRT/MRC) is also compared. The downlink energy efficiency of large scale MIMO systems based on Nakagami fading channel is studied. Two cases are considered in which the CSI is known at both ends of the transmitter and receiver and only the CSI at the receiver is unknown at the sender and transmitter. Two linear processing methods, ZF and MMSE, are used to analyze and compare. First, the system model of the system is obtained, which includes the channel model, a new circuit power model and the signal model based on Nakagami channel, and then the expression of system energy efficiency is obtained based on the system model. Based on this expression, we can analyze the optimal solution of energy efficiency and verify it by numerical analysis. The energy efficiency of distributed antenna system under different cell structure from the previous two chapters is studied and compared with the centralized energy efficiency based on the cell structure. Firstly, according to the different configurations of antennas at the transmitter and receiver, the approximate expression of the energy efficiency of distributed antenna system is obtained in a dual fading channel, and the optimal solution of the parameters that make the maximum energy efficiency in each case is derived. Such as the optimal transmission power, base station antenna number and so on. This chapter also studies the energy efficiency of distributed large-scale MIMO systems based on Nakagami fading channels. Then we compare the distributed and centralized energy efficiency performance in each case and the energy efficiency in distributed Nakagami channel by numerical analysis, and verify the accuracy of the theoretical analysis in both cases. Finally, in connection with the reality, we consider that the number of receiving (user equipment) antennas in the downlink communication during the daily base station erection generally does not exceed the number of transmitting (base station) antennas. Therefore, it can be concluded that the energy efficiency of distributed antenna is generally more prominent than that of centralized antenna, which shows that distributed antenna system is of great significance to the research of green communication technology.
【学位授予单位】：南京邮电大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN919.3
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