Schaltungstheoretische Methoden in der Kommunikationstheorie

在本研究项目中，研究了物理定律对多天线通信的理论限制，并提出了在这些限制范围内进行优化设计的解决方案。多端口理论为物理上一致地推导出多天线通信系统的各种品质因数提供了平台。然而，到目前为止，使用该理论获得的结果大多基于相当理想化的假设--如没有热量损失--不包括重要方面--如带宽和其他性能指标之间的权衡--并依赖于物理模型，这些模型忽略了工程现实的重要部分--例如需要天线支撑结构和天线附近的其他复杂障碍物，如人体。因此，这项研究项目的一部分集中于克服过度理想化的问题，从而得出理论预测与实际相符的合理模型，并从理论上获得最佳性能的系统参数。在这个研究项目中，通道，如在信息理论和信号处理的抽象层中所看到的，不是先验给定的，而是构成设计的一部分。在我们的方法中，天线、它们在空间中的布置、阻抗匹配网络和低噪声放大器构成了信道的一部分。通过联合设计这些元素，将分析和优化所产生的信息理论和信号处理信道相对于诸如信道容量之类的一些优值系数。我们还希望深入了解通信的物理限制，特别是它们对匹配网络性能的影响。

In this research project, the theoretical limits of multi-antenna communications which are imposed by physical law are investigated and solutions for optimum design within those limits are developed. Multiport theory provides a platform for the physically consistent derivation of various figures of merit of multi antenna communication systems. Yet the results obtained up till now using this theory are mostly based on rather idealistic assumptions – such as absence of heat loss –, not including important aspects – like the trade-off between bandwidth and other performance measures –, and rely on physical models which ignore important parts of engineering reality – such as the need for antenna support structures and other complicated obstacles within the vicinity of the antennas such as a human body. A part of this research project is therefore focused on overcoming issues due to over-idealization, and, thus, to arrive at sound models for which theoretical predictions are in good agreement with reality and from which the system parameters for optimum performance can be obtained from the theory. In this research project, the channel, as seen in the information theory and signal processing layer of abstraction, is not apriori given, but rather forms part of the design. In our approach, antennas, their arrangement in space, impedance matching networks, and lownoise amplifiers form part of the channel. By jointly designing these elements, the resulting information theoretic and signal processing channel with respect to some figure of merit, such as channel capacity will be analyzed and optimized. We also hope to gain deep insight into the physical limits of communications, especially their influence on the performance of matching networks.