近距离多天线无线通信关键技术研究

发布时间：2018-05-14 00:00

本文选题：近距离多天线信道 + LOS信道　；参考：《电子科技大学》2016年博士论文

【摘要】：新一代移动通信系统对低功耗、泛在接入、极高频谱效率的迫切需求,驱动了近距离多天线通信场景所占的比例越来越大。其突出特征是多天线阵列尺寸与收发通信距离可以比拟,电磁信号传播的球面特征表现的更加充分,不再适合采用远距离通信中的平面波假设。但是,目前对于球面波特征下的近距离多天线信道的通信能力和实现其通信能力的关键技术还处于探索阶段。为此,本文围绕这两方面的内容开展了初步的研究工作。在评估“通信能力”方面,重点研究了近距离多天线信道的空间自由度和信道容量,给出了近距离天线位置与容量界限的内在关系;在“实现通信能力的关键技术”方面,通过优化天线阵元位置,提高了近距离多天线LOS信道的容量,以及提出了最大化近距离多天线信道容量的预编码传输。具体工作包括:首先,研究了近距离多天线信道容量。利用球面波模型,推导了发射端未知信道状态信息下多发两收近距离LOS信道容量的解析表达式,在此基础上给出了两发两收近距离LOS信道容量的概率密度函数、累积分布函数和均值容量的解析表达式,以及富散射环境中多发两收近距离Ricean衰落信道的遍历容量。理论和仿真结果表明:近距离多天线LOS信道容量由波长、发射天线数、阵元间隔、收发通信距离和阵列方向决定,并且随着这些参数剧烈的波动;近距离多天线LOS信道容量的空间统计信息由收发阵列孔径乘积与收发通信距离的比值决定,随着比值的增大,获得更高容量的概率随之增加;富散射环境下多发两收近距离Ricean衰落信道的遍历容量完全由Ricean K因子和天线阵元位置所决定,可通过合理设计天线阵元位置得到最大的遍历容量。特别的,在三发两收的天线阵列中,当信噪比为20d B,Ricean K因子为5d B时,通过优化天线阵元布局,能达到最大容量12.85bps/Hz。其次,研究了近距离多天线LOS信道的空间自由度。利用球面波模型,分别研究了三维空间中远距离和近距离多天线LOS信道的空间自由度。理论和仿真结果表明,在单极化线性阵列下的远距离多天线LOS信道中只能得到一个空间自由度,然而在近距离多天线LOS信道中可通过合理设计阵列方向和天线尺寸得到多个空间自由度。再次,通过优化天线阵元位置,提高了近距离多天线LOS信道的容量。针对固定无线接入中任意方向的两发两收天线阵列,在联合考虑路径损耗和相位差的影响下,通过优化天线阵元位置,实现了近距离LOS信道的最大容量。然后,针对终端移动台在室内某一区域内移动的情况下,基于蚁群算法,通过优化发射天线阵元位置,提高了区域内的平均容量。最后,研究了近距离多天线信道的预编码传输。使用球面波模型,分别推导了两发多收近距离LOS信道和富散射环境中近距离Ricean信道的预编码传输方向和其功率分配的解析表达式,并给出了其空间复用和波束成形的充要条件。理论和仿真结果表明,预编码传输下的信道容量要大于或等于在所有方向进行等功率传输的信道容量,并且两者的差别随着两个发射天线空间特征图夹角的余弦的绝对值增大而增大。特别的,在两发三收富散射环境的近距离Ricean信道中,当信噪比为5d B,Ricean K因子为30d B时,两者的最大差别能达到0.7bps/Hz。论文在近距离多天线通信方面做出的上述研究成果,对新一代移动通信网、宽带无线接入网、无线物联网等无线通信系统的设计具有现实指导意义。
[Abstract]:The new generation mobile communication system has the urgent demand for low power, ubiquitous access and high spectral efficiency, which drives the proportion of the near distance multi antenna communication scene. Its prominent feature is that the size of the multi antenna array is compared with the distance of the transceiver communication, and the spherical characteristic of the electromagnetic signal is more fully displayed, and it is no longer suitable for mining. The plane wave assumption in long distance communication is used. However, at present, the communication ability and the key technology to realize the communication ability of the near distance multi antenna channel under the spherical Potter sign are still in the exploration stage. Therefore, this paper has carried out the preliminary research work around these two aspects. The intrinsic relationship between the location of the close range antenna and the capacity limit is given, and the capacity of the near distance multi antenna LOS channel is improved by optimizing the location of the antenna element, and the maximum near range multi antenna channel capacity is proposed. The specific work includes: first, the capacity of the near distance multi antenna channel is studied. By using the spherical wave model, the analytical expression of the capacity of the multiple two close range LOS channel under the unknown channel state information of the transmitter is derived. On this basis, the probability density function of the capacity of the two hair two close range LOS channel is given, and the cumulative probability density function is given. The analytic expression of the distribution function and the mean value capacity and the ergodic capacity of multiple two close range Ricean fading channels in the rich scattering environment. The theoretical and simulation results show that the capacity of the LOS channel of the near distance multi antenna is determined by the wavelength, the number of transmitting antennas, the interval of the array, the distance and direction of the communication and the direction of the array. The spatial statistical information of the capacity of the near distance multi antenna LOS channel is determined by the ratio of the number of the aperture product to the transceiver and the distance between the transmission and receiving communication. As the ratio increases, the probability of obtaining higher capacity increases. The traversal capacity of the multiple two receive close range Ricean fading channels in the rich scattering environment is entirely from the Ricean K factor and the antenna element. The maximum ergodicity of the antenna array can be obtained by the location of the antenna. In the antenna array of three hair two, when the signal to noise ratio is 20d B and the Ricean K factor is 5D B, the maximum capacity 12.85bps/Hz. can be achieved by optimizing the antenna array element layout, and the space freedom degree of the near distance multiple antenna LOS channel is studied. Using the spherical wave model, the spatial freedom degree of the multi antenna LOS channel in the distance and near distance in the three-dimensional space is studied. The theoretical and simulation results show that only one space degree of freedom can be obtained in the long distance multi antenna LOS channel under the single polarized linear array, but the array can be designed by a reasonable array in the short distance multi antenna LOS channel. The direction and antenna size are multiple space degrees of freedom. Thirdly, by optimizing the position of antenna element, the capacity of the near distance multi antenna LOS channel is improved. For the two antenna array with two antennas in any direction in the fixed wireless access, with the influence of the path loss and phase difference, the close distance of the antenna element is optimized by optimizing the antenna array position. In the case of the maximum capacity of the LOS channel, for the terminal mobile station moving in an indoor area, the average capacity of the region is improved by optimizing the location of the antenna array element based on the ant colony algorithm. Finally, the precoding transmission of the near distance multi antenna channel is studied. The spherical wave model is used to deduce two rounds. The precoding transmission direction and the analytical expression of the power distribution of the near range Ricean channel in the near distance LOS channel and the rich scattering environment are given, and the necessary and sufficient conditions for the space multiplexing and beamforming are given. The channel capacity, and the difference between the two, increases with the absolute value of the cosine of the two space feature maps of the two transmitting antennas. In particular, when the signal to noise ratio is 5D B and the Ricean K factor is 30d B, the maximum difference between the two antennas can reach the close range multiple antenna in 0.7bps/Hz. paper. The above research results in communication are of practical significance to the design of a new generation of mobile communication network, broadband wireless access network, wireless Internet of things and other wireless communication systems.

【学位授予单位】：电子科技大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TN92

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