Wireless Channel Sounding using Distributed and Synthetic Arrays

随着无线系统采用越来越复杂的方法和技术来实现更大的容量、可靠性和能源效率，它们的性能对更大范围的传播损伤变得越来越敏感，信道模型也变得越来越复杂。我们建议开发新的和改进的方法来使用合成或分布式阵列来表征无线信道，从而支持在新的和具有挑战性的场景中设计和部署下一代无线系统。预期的结果包括：1)更具成本效益的信道测深仪架构，2)从原始信号数据中提取信道特征的更好方法，3)以信道模型的形式捕获信道特征的更好方法。分布式阵列信道测深仪。我们建议用光延迟线多路复用器取代目前分布式天线信道测深器中使用的机械开关。通过消除快速机械开关的高成本、低开关速度和低再现性，并提供同步采样、超快速多路复用（微秒延迟）和出色的再现性，这种通道测深仪有可能彻底改变这一领域的工作。我们将专注于开发更好的方法，从这种信道测深器产生的原始信号数据中提取信道特性，以及更好的方法，以DAS信道模型的形式捕获测量的信道特性。最终，更有效的DAS信道探测仪和DAS信道模型的标准化将促进替代架构和协议之间的公平比较，并促进DAS性能增强和成本降低的进步。合成阵列信道测深仪。空间信道模型在预测包括高速铁路在内的移动环境中基于多输入多输出（MIMO）的无线通信系统的性能方面起着至关重要的作用。目前表征空间信道的方法需要在发射器和接收器上同时使用机械可操纵的定向天线或虚拟/物理天线阵列，但这些通常不适合在移动环境中使用。我们建议，适合移动环境的空间信道测量系统可以通过将其转换为双基地合成孔径雷达（BiSAR）来大大简化，该双基地合成孔径雷达具有一个固定的发射机和一个相对于环境移动的移动接收器。与传统的空间信道测深仪相比，所需的硬件是微不足道的，并且适合操作员的日常使用。最终，更高效和有效的空间信道测深仪将提高对影响MIMO系统性能因素的学术和实践理解。

As wireless systems have adopted increasing complex methods and techniques to achieve greater capacity, reliability and energy efficiency, their performance has become increasingly sensitive to a broader range of propagation impairments and channel models have become evermore complex. We propose to develop novel and improved methods for characterizing wireless channels using either synthetic or distributed arrays and thereby support the design and deployment of next generation wireless systems in new and challenging scenarios. Anticipated outcomes include: 1) more cost effective channel sounder architectures, 2) better methods for extracting channel characteristics from raw signal data, 3) better methods for capturing the channel characteristics in the form of channel models.Distributed Array Channel Sounders. We propose to replace the mechanical switches used in current distributed antenna channel sounders with optical-delay-line multiplexers. By eliminating the high cost, slow switching speeds and poor reproducibility of fast mechanical switches and providing simultaneous sampling, ultra-fast multiplexing (microsecond delays) and excellent reproducibility, such channel sounders have the potential to revolutionize work in this area. We will focus on developing better methods for extracting channel characteristics from raw signal data produced by such a channel sounder and better methods for capturing the measured channel characteristics in the form of DAS channel models. Ultimately, more effective DAS channel sounders and standardization of DAS channel models will facilitate fair comparison between alternative architectures and protocols and spur advances in DAS performance enhancement and cost reduction. Synthetic Array Channel Sounders. Spatial channel models play a crucial role in predicting the performance of multiple-input multiple-output (MIMO)-based wireless communication systems in mobility environments including high speed rail. Current approaches to characterizing spatial channels require either mechanically steerable directional antennas or virtual / physical antenna arrays at both the transmitter and receiver, but these are generally unsuitable for use in mobility environments. We suggest that a spatial channel measurement system suitable for mobility environments can be simplified considerably by casting it as a bistatic synthetic aperture radar (BiSAR) with a stationary transmitter and a mobile receiver that moves with respect to the environment. The hardware required is trivial compared to conventional spatial channel sounders and lends itself to routine use by operators. Ultimately, more efficient and effective spatial channel sounders will improve both academic and practical understanding of the factors that affect MIMO system performance.