Propagation and Capacity Studies for Multi-Polarized MIMO Communication Systems

未来的无线系统以有限的频谱提供高数据速率服务，将通过利用空间维度提供的额外自由度来增加容量。这种系统的例子是多输入多输出(MIMO)系统，其中在每一端使用多个天线来缩放自由度数量。通过利用电磁波的各种电场和磁场分量，可以获得更多的自由度。假设发射端和接收端采用相同的配置，独立衰落的信息理论结果表明，系统容量与天线数和每个天线的场分量数的乘积成线性关系。这使得系统设计者考虑在可能的情况下使用大量的天线。然而，随着这些系统迅速走向实现，能够针对现实的传播环境分析和设计这样的系统是很重要的，在现实的传播环境中，独立性的数量天生就是有限的。因此，在该项目下，个人信息系统将：(1)开发包括波的去极化和多次散射的随机传播模型；(2)研究由于将天线限制在固定体积和现实环境中而导致的元素相关和相互耦合所产生的容量限制；以及(3)设计和分析在这些环境中利用各种形式的信道状态信息的健壮的单用户和多用户通信技术。该项目的技术优点在个人信息系统的各个领域的根本进步以及这些领域的密切联系方面都是显著的。MIMO系统的建模技术将代表着针对这一重要新环境的电磁建模的重大进展。容量分析将引入新的技术和数学工具，这些将被证明是社区普遍使用的。基于导出的电磁模型的通信系统设计和分析技术代表了一种新的稳健通信系统设计方法。然而，同样重要的是，PI的两个领域的连接如何推动项目的目标；尤其是，通信研究有助于确定将对系统设计和分析产生重大影响的电磁模型的参数，并且电磁模型驱动设计和分析MIMO系统所需的技术和工具。这一有希望的技术优点在这项提案中得到了证实，因为它描述了私人投资机构的拟议工作和最近的工作--包括单独开展和合作开展的工作。首先，本研究开发的模型和技术将被MIMO系统的研究人员和设计者广泛使用。特别是，由这个多学科团队开发的这种模型和技术将保证这种模型和技术的准确性，并确保结果的形式能够服务于研究界对算法的分析和设计。其次，该项目将继续该团队成功的本科生研究项目，该项目已将多名马萨诸塞大学的本科生送往全国各地的顶尖研究生项目，并以真诚的奉献精神支持两名PI。最后，该项目将进一步推动个人投资机构跨越将电磁学与通信理论分开的边界进行强有力的合作，并将进一步理解，不仅需要跨典型网络模型的各层进行综合学术研究，而且还需要在物理层本身进行综合学术研究。

0300130JanaswamyFuture wireless systems, providing high data-rate services with limited spectrum, will increase capacity by exploiting additional degrees of freedom provided by the spatial dimension. Examples of such systems are multiple-input multiple-output (MIMO) systems, where multiple antennas are employed at each end to scale the number of degrees of freedom. Further degrees of freedom can be obtained through employing various electric and magnetic field components of the electromagnetic wave. Assuming that the same configuration is employed at both the transmitter and receiver, information theoretic results for independent fading demonstrate that the system capacity scales linearly with the product of the number of antennas and the number of field components per antenna employed. This has led system designers to consider systems with a vast number of antennas where possible. However, as these systems push rapidly towards implementation, it is important to be able to analyze and design such systems for realistic propagation environments, where the amount of independence is inherently limited. Thus, under this project, the PIs will: (1) develop stochastic propagation models that include depolarization and multiple scattering of waves (2) study capacity limitations arising from element correlation and mutual coupling that results from restricting antennas to a fixed volume and realistic environment, and (3) design and analyze robust single-user and multi-user communication techniques that exploit various forms of channel state information in these environments.The technical merit of this project is significant both in fundamental advances in the individual areas of the PIs and also in the close connection of such. The modeling techniques for MIMO systems will represent significant advances in electromagnetic modeling for this important new environment. The capacity analyses will introduce new techniques and mathematical devices that will prove of general use to the community. The techniques of design and analysis of communication systems based on the derived electromagnetic models represent a new approach to robust communication system design. Just as importantly, however, is how the connection of the two areas of the PIs furthers the goals of the project; in particular, the communications research helps define the parameters of the electromagnetic model that will have a significant impact on system design and analysis, and the electromagnetic models drive the techniques and tools required to design and analyze MIMO systems. This promising technical merit is substantiated in this proposal by the description of the proposed and recent work of the PIs - both individually and in collaboration.The broader impact of this project will be significant in a number of ways. First, the models and techniques developed in this research will be used widely by researchers and designers of MIMO systems. In particular, the development of such models and techniques by this multidisciplinary team will guarantee both the accuracy of such and that the results are in a form that can serve the research community in the analysis and design of algorithms. Second, this project will continue the team's successful program of undergraduate research, which has sent a number of University of Massachusetts undergraduates to top graduate programs around the country, and supports two PIs with a sincere dedication to undergraduate teaching. Finally, this project will further the strong collaboration of the PIs across the boundary that separates electromagnetics from communication theory, and it will further the understanding that integrated academic research is not only needed across layers in the typical networking model but also within the physical layer itself.