Energy Efficient Millimeter Wave Massive MIMO Wireless Communications

用于大规模连接的低功耗高性能无线设备。所谓的“物联网”（IoT）是指所有类型的物理设备的互联网络，以便使它们能够收集数据并相互通信，或者通过接入点允许它们与互联网交换数据，从而与整个世界交换数据。这类设备的用途非常广泛，包括医药、交通、民用基础设施、环境监测以及个人通信。这些设备能够感知周围环境，并与彼此和互联网进行通信，这将导致一场革命，改善我们的健康、环境和整体生活质量。为了使物联网革命成为现实，需要取得重大进展，以降低这些设备的成本（以便它们可以无处不在地部署）以及它们的能耗（以便它们可以长时间运行而无需更换）。在过去的几十年里，数字硬件的进步导致了电路的小型化，这反过来又使得带有数十亿晶体管的复杂微处理器占据了一个比针脚头还小的空间。纳米制造技术的进步使得微型传感器和致动器的制造成为可能，这些传感器和致动器只需要非常少的能量或尽可能少地接触它们的环境就可以运行。然而，与模拟电子转换，放大和通信相关的物理限制已经较慢地克服。该项目的目标是帮助弥补这一差距，并开发简单、低功耗、低复杂性的射频设备，这些设备可以与复杂的软件结合使用，使物联网愿景成为现实。需要新的技术和硬件实现来减少收发器的尺寸、成本和功耗，从而实现无处不在的物联网设备部署以及节能的千兆位/秒无线网络。在这一愿景的激励下，我们的项目专注于几个新的研究计划，将推动无线系统朝这个方向发展：(1)基于可重构的一位直接检测（DDA）天线的大规模MIMO射频硬件的新概念，可能既不需要混频器，也不需要本地振荡器的产生和分配，并实现更简单的天线馈电，高能效，更低的成本和超快的信号；(2)基于电感调谐的新型集成电路实现，以验证DDA概念，并说明如何通过无线LO分布进行无混频器解调，从而大大简化毫米波频段的射频前端；(3)基于角频域的新推导，不依赖于白量化噪声假设的1位adc / dac的上行/下行信道容量结果。这些结果将更适合于倾向于稀疏和频率选择性的毫米波信道。(4)具有1位dac的新型有限域下行预编码器，不需要乘法和加法的标准算术运算（因此大大简化了必要的数字计算），但仍然大大优于传统方法，并且可以与信道编码技术相结合；(5)考虑到数据中的带外发射和互调产品的低分辨率ADC和DAC硬件的更现实的模型，以确定在什么条件下可以忽略它们以及如何减轻它们。预期的研究解决了下一代无线系统的关键挑战，也与低功耗物联网技术的成功高度相关。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Low-Power High-Performance Wireless Devices for Massive ConnectivityA. Lee Swindlehurst and Michael Green University of California IrvineThe so-called "Internet of Things'' (IoT) refers to the inter-networking of all types of physical devices in order to allow them to collect data and communicate with one another, or with an access point that allows them to exchange data with the internet and hence the entire world. There is a plethora of applications where such devices could be useful, including medicine, transportation, civil infrastructure, environmental monitoring, as well as personal communications. The ability of these devices to sense their environment and communicate with each other and the internet will lead to a revolution that will improve our health, our environment and our overall quality of life. In order for the IoT revolution to become a reality, significant advances are needed to reduce the cost of these devices (so that they can be deployed ubiquitously) as well as their energy consumption (so that they can operate for long periods of time without replacement). Advances in digital hardware over the past decades has resulted in circuit miniaturization that has in turn allowed for complicated microprocessors with billions of transistors to occupy a space no bigger than the head of a pin. Advances in nanofabrication have allowed for the creation of tiny sensors and actuators that require only very small amounts of energy or minimal access to their environment in order to operate. However, the physical constraints associated with analog electronic conversion, amplification and communication have been slower to be overcome. The goal of this project is to help remedy this gap, and develop simple, low-power, low-complexity radio-frequency devices that can be used in conjunction with sophisticated software to enable the IoT vision to become a reality. New techniques and hardware implementations are needed that reduce the size, cost and power consumption of transceivers that will enable ubiquitous deployment of IoT devices as well as energy efficient gigabit-per-second wireless networks. Motivated by this vision, our project focuses on several new research initiatives that will push wireless systems in this direction: (1) A new concept for massive MIMO RF hardware based on reconfigurable one-bit direct detection (DDA) antennas that potentially require neither mixers nor local oscillator generation and distribution, and enable simpler antenna feeding, high energy efficiency, lower cost and ultrafast signaling; (2) New integrated circuit implementations based on inductor tuning to validate the DDA concept and illustrate how mixer-less demodulation via wireless LO distribution can be used to dramatically simplify the RF front end for millimeter-wave frequency bands; (3) Uplink/downlink channel capacity results with one-bit ADCs/DACs that do not rely on the assumption of white quantization noise, based on a new derivation in the angular frequency domain. These results will be better suited for millimeter-wave channels that tend to be sparse and frequency-selective. (4) New types of finite field downlink precoders with one-bit DACs that do not require the standard arithmetic operations of multiplication and addition (and hence considerably simplify the necessary digital computations), and yet still substantially outperform conventional methods and can be combined with channel coding techniques; (5) More realistic models for low-resolution ADC and DAC hardware that account for out-of-band emissions and intermodulation products in the data, in order to determine under what conditions they can be ignored and how they can be mitigated otherwise. The anticipated research addresses critical challenges for next-generation wireless systems and is also of high relevance for the success of low-power IoT technology.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.