Wave diversity in wireless communication

利用传播电波的多样性的方法对无线通信系统的高效运行至关重要。这种多样性发生在两个不同的维度上：空间和时间。它们都对电磁辐射可以携带的信息量构成了基本限制。该项目试图基于传播场的空间频谱的物理概念来呈现这些独立的轴的统一视图，并在信息论和电磁场理论领域之间建立联系。更具体地说，该项目从物理原理定义了多天线信道中的信息传输的概念，并研究了通过该信道传输到接收机的信息量如何依赖于由发射天线和环境中存在的散射体组成的辐射系统的空间带宽和频率带宽。通过将场重构的逆问题归结为空间上的通信问题，并通过严格应用场向量空间上的采样定理来确定信道的相关通信模式，以类似于时间信息内容的方式对空间信息内容进行量化。本研究涉及信息率概念从时间到空间的扩展，旨在揭示这两个维度之间的基本二元性和权衡。

Methods to exploit the diversity of propagating waves are crucial to the efficient operation of wireless communication systems. Such diversity occurs along two different dimensions: space and time. Both of them pose fundamental limits on the amount of information that can be carried by electromagnetic radiation. This project attempts to present a unified view of these separate axes, based on the physical notion of space frequency spectrum of the propagating field, and to draw connections between the fields of information theory and electromagnetic theory.More specifically, the project defines the concept of information transmission in a multiple antenna channel from physical principles, and investigates how the amount of information transported over the channel to the receiver depends on both the spatial and the frequency bandwidth of the radiating system composed by the transmitting antennas and the scattering objects present in the environment. The spatial information content is quantified in a similar fashion than its temporal counterpart, by reducing the inverse problem of field reconstruction to a communication problem in space, and determining the relevant communication modes of the channel by rigorously applying the sampling theorem on the field's vector space. This research involves extensions of the concept of information rate from time to space, and is aimed at revealing fundamental dualities and trade-offs between these two dimensions.