Collaborative Research: EARS: Broadband Mobile Wireless Access Using mm-Waves Bands Beyond 100 GHz

无线通信对我们的生活质量和我们的经济的重要性怎么强调都不为过。虽然网络运营商和研究人员已经做了大量工作来提高现有网络的容量，但仍迫切需要探索新的选择来支持呈指数级增长的无线互联网流量。这项研究将在毫米波波段研究一种全新的频谱，该频谱可以为移动用户提供千兆位链路，使网络运营商能够以优雅的方式扩展容量。到目前为止，毫米波通信大多局限于点对点链路或固定终端的短距离通信。使用毫米波无线电进行移动通信需要对电路、天线、封装以及系统和协议进行彻底的重新思考和共同设计。这项研究将探索120 GHz毫米波电路和系统的设计，使大型无线电阵列能够在相对较长的范围(数百米)内以非常高的数据速率(10Gbps)进行通信。与低于100 GHz的研究相比，这一领域相对来说还没有被探索，只有大约12个工作的收发机演示。研究团队将研究系统和电路架构，以支持波束形成、波束归零、多用户MIMO(多输入多输出)，从而通过空间滤波和干扰抑制实现高效的频谱重用。新的电路设计概念将采用28 nm互补金属氧化物硅(CMOS)技术和用于高功率传输的GaN(氮化镓)晶体管进行原型设计。当波形具有高峰均比(2%的平均效率)时，今天的毫米波发射机的效率非常低，而所提出的发射机架构将使输出功率和效率都提高一个数量级。用CMOS实现的毫米波系统的射程也将从几米增加到数百米，特别是在没有使用透镜的情况下。这项研究将使完全未开发的频谱能够用于5G蜂窝和其他应用。拟议的合作研究项目的技术目标是专注于电路和系统级的硬件平台的实现，该硬件平台可以实现最佳波束形成和波束清零(干扰消除)的研究，同时允许对100 GHz以上的室内和室外信道的传播特性进行实际测量。具体地说，PI、共同PI和一组研究人员将为收发器设计和实施关键构建块，以实现对100 GHz以上通信的测量和表征。该项目涉及四个待调查的主要领域。第一个重点领域将集中于发射机电路设计和集成挑战，并探索用于MIMO应用的硅基功率放大器的技术限制，特别是在100 GHz以上。第二个推力将提供有关GaN晶体管与CMOS的集成的见解，以实现用于数字信号处理和波形整形的高密度逻辑，以及用于发电的高击穿电压GaN器件。第三个推力将集中在天线和系统架构上，以支持波束形成，并特别关注解决有关LO(本机振荡器)生成和分布的问题，以及在大型阵列中找到最优配置以最大限度地减少功耗。最后的推力领域将重点研究在其他推力领域开发的子模块所带来的系统级集成挑战，以生产120 GHz收发机。

The importance of wireless communication on the quality of our lives and on our economy cannot be overstated. While network operators and researchers have done a tremendous job to improve the capacity of existing networks, there is a strong need to explore new options to support the exponentially growing wireless Internet traffic. This research will investigate a completely new spectrum in the mm-wave band that could enable Gigabit links for mobile users, allowing network operators to expand capacity in a graceful manner. Up to now, mm-wave communication has been mostly limited to either point-to-point links or to short-range communication for fixed terminals. Using mm-wave radios for mobile communication requires a complete rethinking and co-design of the circuits, antennas, packages, and systems and protocols. This research will explore the design of mm-wave circuits and systems at 120 GHz, enabling large arrays of radios to communicate with very high data rates ( 10 Gbps) over relatively long ranges (hundreds of meters). Compared to research below 100 GHz, this area is relatively unexplored, with only about a dozen demonstrations of working transceivers. The research team will investigate system and circuit architectures to support beam forming, beam nulling, multi-user MIMO (multiple-input multiple-output), allowing efficient spectrum re-use through spatial filtering and interference rejection. Novel circuit design concepts will be prototyped in 28 nm CMOS (Complementary Metal-Oxide Silicon) technology along with GaN (Gallium Nitride) transistors for high power transmission. Today's mm-wave transmitters are extremely inefficient when the waveform has a high peak to average ratio (2% average efficiency), whereas the proposed transmitter architectures will increase both the output power and efficiency by an order of magnitude. The range of mm-wave systems realized in CMOS, particularly without the use of lens, will also be increased from a few meters to hundreds of meters. This research will enable the exploitation of completely untapped spectrum for 5G cellular and beyond applications.The technical objective of the proposed collaborative research project is to focus on circuit and system level realization of a hardware platform that can enable the study of optimal beam forming and beam nulling (interference cancellation), while allowing practical measurements to be carried out on the propagation characteristics of indoor and outdoor channels above 100 GHz. Specifically, the PI, co-PI and a team of researchers will design and implement key building blocks for the transceiver to enable measurement and characterization of communication above 100 GHz. This project involves four main thrust areas to be investigated. The first thrust area will focus on transmitter circuit design and integration challenges and explore technology limits for silicon-based power amplifiers for MIMO applications in CMOS, especially above 100 GHz. The second thrust will provide insight regarding the integration of GaN transistors with CMOS to allow for high-density logic for digital signal processing and waveform shaping, and high breakdown voltage GaN devices for power generation. The third thrust will focus on antenna and system architectures to support beam forming with special attention to solving problems regarding LO (local oscillator) generation and distribution and finding the optimal configuration to minimize power consumption in a large array. The final thrust area will focus on investigating system level integration challenges from the sub-modules developed in the other thrust areas to produce a 120GHz transceiver.