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获得更大的容量、可靠性和能量效率，其性能对更广泛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)更具成本效益的通道探测仪架构，2)从原始信号数据中提取通道特征的更好方法，3)以通道模型的形式捕获通道特征的更好方法。*分布式阵列通道探测仪。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探测器中使用的机械开关。通过消除快速机械开关的高成本、慢切换速度和较差的重复性，并提供同步采样、超快多路复用(微秒延迟)和出色的重复性，这种通道探测仪具有变革这一领域工作的潜力。*我们将专注于开发更好的方法来从这样的频道探测仪产生的原始信号数据中提取频道特征，以及以DAS频道模型的形式捕获测量的频道特征的更好方法。最终，更有效的DAS通道探测器和DAS通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。*合成阵列声道发声器。在包括高速铁路在内的移动环境中，空间信道模型对于预测基于多输入多输出(MIMO)的无线通信系统的性能起着至关重要的作用。目前用于描述空间信道的方法需要在发射机和接收机上同时使用机械可操纵的定向天线或虚拟/物理天线阵列，但这些方法通常不适合在移动环境中使用。*我们建议将适用于移动环境的空间信道测量系统简化为双基地合成孔径雷达(BiSAR)，其中发射机固定，移动接收机随环境移动。与传统的空间通道探测仪相比，所需的硬件微不足道，并且适合运营商的日常使用。最终，更高效和有效的空间信道探测器将提高对影响MIMO系统性能的因素的理论和实践理解。

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.