SBIR Phase I: Tacet: High-Speed TV-Band White Space Networks with Implicit Multi-User Beamforming

该项目的更广泛的影响/商业潜力将是开发一个可扩展的框架，用于通过利用隐式信道探测来提高无线多输入多输出（MIMO）系统在具有长信道相干时间的环境中的频谱效率。到目前为止，标准委员会和设备供应商已经避免了隐式信道探测，因为关于其使用的关键技术问题仍然没有答案。通过提供用于隐式信道探测的零开销方法，所提出的系统将能够向媒体接入控制器（MAC）和应用层提供丰富的环境和用户移动性数据，这对MU-MIMO系统的速率和组选择的未来设计具有强烈的影响。随着针对未许可TVWS无线设备的商业化，与现有的单天线TVWS解决方案相比，所提出的4天线系统将能够提供至少4倍的网络容量增加，而不会遭受现有多用户MIMO系统中典型的协议开销拥塞。这种方法的一个组成部分是能够在低成本的软件定义无线电硬件上实现该技术，将该技术置于寻求低成本宽带数据解决方案的服务不足社区的范围内。这个小型企业创新研究（SBIR）第一阶段项目将展示一种创新的隐式波束成形协议，该协议消除了电视波段白色空间（TVWS）无线电信道中的信道探测开销，从而实现高效和高速的最后一英里未授权无线网络部署。该项目将为软件定义无线电阵列开发和基准测试实用的隐式信道互易性校准，同时利用创新的软件定义无线电信号流，使系统能够在低成本的商品片上系统硬件上实现。这两种方法都代表了与商业系统中现有的波束成形方法的背离，商业系统中的波束成形方法依赖于开销密集的显式波束成形和用于信号处理和波束成形计算的实时并行硬件。虽然在学术研究论文中证明是可行的，但这两项关键创新尚未在操作系统中得到验证，本项目还调查了实施的几个已知障碍。最后，通过跟踪驱动的系统仿真，在真实的TVWS信道上对所提出的隐式波束形成系统进行了验证。据我们所知，这是第一次隐式波束成形系统将在商业硬件和真实的无线信道上进行测试。

The broader impact/commercial potential of this project will be to develop a scalable framework for increasing the spectral efficiency of wireless Multiple-In, Multiple-Out (MIMO) systems in environments with long channel coherence time by leveraging implicit channel sounding. To date, standards committees and equipment vendors have avoided implicit channel sounding since key technical questions regarding its use remained unanswered. By providing a zero-overhead method for implicit channel sounding, the proposed system will be able to provide rich environment and user mobility data to the Media Access Controller (MAC) and application layer, with strong implications for the future design of rate and group selection for MU-MIMO systems. With commercialization targeted at unlicensed TVWS wireless devices, the proposed 4-antenna system will be able to provide at least a 4-fold increase in network capacity compared to existing single-antenna TVWS solutions, without suffering from protocol overhead congestion typical in existing multi-user MIMO systems. Integral to this approach is the ability to implement the technology on low-cost software-defined radio hardware, placing this technology within the reach of underserved communities looking for low-cost broadband data solutions.This Small Business Innovation Research (SBIR) Phase I project will demonstrate an innovative implicit beamforming protocol that eliminates channel sounding overhead in TV-band White Space (TVWS) radio channels, enabling efficient and high-speed, last-mile unlicensed wireless network deployments. The project will develop and benchmark practical implicit channel reciprocity calibration for software-defined radio arrays, while utilizing an innovative software-defined radio signal flow that allows the system to be implemented on low-cost commodity system-on-chip hardware. Both approaches represent a departure from existing methods of beamforming in commercial systems, which rely on both overhead-intensive explicit beamforming and real-time parallel hardware for signal processing and beamforming calculation. While shown to be feasible in academic research papers, both key innovations have yet to be validated in an operational system and several known barriers to implementation are investigated in this project. Finally, the proposed implicit beamforming system will be validated on real TVWS channels though trace-driven system emulation. To our knowledge, this is the first time that an implicit beamforming system will be tested on commercial hardware and on real wireless channels.