Schaltungstheoretische Methoden in der Kommunikationstheorie

在本研究计画中，将探讨多天线通讯的物理限制，并在这些限制内，提出最佳设计的解决方案。多端口理论为多天线通信系统的各种品质因数的物理一致性推导提供了一个平台。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-例如没有热损失-，不包括重要的方面-例如带宽和其他性能指标之间的权衡-，依赖于物理模型，而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它复杂障碍物，例如人体。因此，本研究项目的一部分集中在克服由于过度理想化而产生的问题，从而获得理论预测与现实吻合良好的合理模型，并从理论中获得最佳性能的系统参数。在这个研究项目中，信道，在信息理论和信号处理抽象层中看到的，不是先验给定的，而是设计的一部分。在我们的方法中，天线，它们在空间中的排列，阻抗匹配网络，和低噪声放大器形成的通道的一部分。通过联合设计这些元件，将分析和优化关于诸如信道容量的某些品质因数的所得信息理论和信号处理信道。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.