EARS: Compact Adaptive MIMO Receivers

EAR：紧凑型自适应MIMO接收器Brian A.Floyd、Jacob J.Adams和Brian L.Hughes北卡罗来纳州立大学电气和计算机工程系智力优势：对多输入多输出(MIMO)通信的研究表明，在发射器和接收器处使用多天线可以显著提高无线多径信道的容量。由于许多无线设备的尺寸有限，使用多个天线需要很小的间距，这会导致天线之间强烈的频率依赖耦合。耦合会大大降低接收功率、分集和容量。以往的工作表明，在接收端进行阻抗匹配可以恢复大部分丢失的系统容量；然而，这些匹配网络可能很复杂且难以实现，并且它们必须适应不断变化的信道和天线条件。最后，现有的用于MIMO系统的天线是以一种特别的方式设计的，没有考虑寻找方法来完全捕获所有可用自由度并最大化孔径的容量。该项目的目标是将信息论、天线工程和射频(RF)电路设计相结合，以实现紧凑型宽带多天线接收机的新方法。总体方法是开发多模式天线、可重新配置的接收器和通信算法，它们协同工作以最大化底层信道的容量。具体地说，将开发一种系统的方法来设计基于信息理论度量的MIMO天线，例如容量，通过控制和塑造本征模的相互耦合。还将开发使用可重新配置的基带阻抗匹配网络的新型MIMO接收器，该网络使用无源混频优先架构将频率转换为RF。最后，将开发通信和信号处理算法，这些算法可以有效地检测和调整匹配网络，以响应不断变化的信道条件。为了评估这些新技术，将构建一个硬件试验台，由一个二端口自适应MIMO接收机、两个端口紧凑型天线和一个用于控制和信号处理的数字接口组成。最终，随着技术扩展到更大的多端口系统，将探索性能和复杂性的扩展。广泛影响：这个多学科项目提供了MIMO接收器设计的整体视图，并开发了新的模型、天线设计方法、通信算法和匹配技术，可以显著提高未来蜂窝和无线局域网的容量和性能。如果成功，该项目将使MIMO技术即使在物理上很小、天线相互耦合很强的接收器中也能使用，从而提高数据速率、更大范围和/或更长的电池寿命。理论和实验的结合将为学生提供各级参与的机会。

EARS: Compact Adaptive MIMO ReceiversBrian A. Floyd, Jacob J. Adams, and Brian L. HughesDepartment of Electrical and Computer EngineeringNorth Carolina State UniversityIntellectual Merit: Research on multi-input multi-output (MIMO) communications has shown that using multiple antennas at both the transmitter and receiver can dramatically improve the capacity of wireless multipath channels. Since many wireless devices are limited in size, using multiple antennas requires close spacing which leads to strong, frequency-dependent coupling between antennas. Coupling can profoundly reduce received power, diversity and capacity. Prior work suggests that impedance matching at the receiver can reclaim most of the lost system capacity; however, these matching networks can be complex and difficult to implement, and they must adapt to changing channel and antenna conditions. Finally, existing antennas for MIMO systems are designed in an ad hoc manner, with no consideration given to finding methods to fully capture all available degrees of freedom and maximize the capacity of the aperture. The goal of this project is to combine information theory, antenna engineering, and radio-frequency (RF) circuit design to enable new approaches to realize compact broadband multi-antenna receivers. The overall approach is to develop multi-mode antennas, reconfigurable receivers, and communication algorithms that act in concert to maximize capacity of the underlying channel. Specifically, a systematic method will be developed to design MIMO antennas based on information-theoretic metrics, such as capacity, by controlling and shaping mutual coupling of the eigenmodes. Novel MIMO receivers will also be developed that employ reconfigurable baseband impedance matching networks which are frequency translated to RF using passive mixer-first architectures. Finally, communication and signal processing algorithms will be developed that can efficiently sense and adjust the matching networks in response to changing channel conditions. To evaluate these new technologies, a hardware test-bed will be constructed consisting of a two-port adaptive MIMO receiver, two-port compact antenna, and a digital interface for control and signal processing. Ultimately, the scaling of performance and complexity will be explored as the techniques are extended to larger multi-port systems.Broader Impacts: This multi-disciplinary project provides a holistic view of MIMO receiver design and develops new models, antenna design methods, communications algorithms and matching techniques which could significantly increase the capacity and performance of future cellular and wireless local area networks. If successful, this project would enable MIMO techniques to be employed even in physically small receivers with strong antenna mutual coupling, allowing increased data rates, larger range, and/or longer battery lives. The combination of theory and experiment will provide opportunities for student participation at all levels.