Reconfigurable All-Digital CMOS Frequency Synthesizers for Cognitive and Milimeter-Wave Radios

无线通信在全球范围内对经济、社会和科学产生了不可估量的影响。然而，随着最近智能手机和平板电脑的爆炸式增长，以及传感器群和物联网等新型网络的预期出现，目前的授权频谱接入模式似乎越来越不可行。目前正在积极研究两种互补的解决方案：(1)频谱共享认知无线电和(2)基于密集、短距离毫米波链路的无线网络。开发高度可重构、高能效的无线电对这些技术的长期成功至关重要。本提案通过开发敏捷，频谱纯净和可重构的“通用”频率合成器的设计技术来解决关键的电路级挑战。智能优势：与目前无线电中常用的基于模拟的频率合成器相比，全数字频率合成器对纳米级CMOS的模拟缺陷不太敏感，具有高度可重构性，可以快速跨技术节点移植，因此是通用频率合成的有希望的候选器件。然而，宽可调谐振荡器的设计、高分辨率/高线性时间-数字转换器以及两者之间的接口是成功实现全数字频率合成器的障碍。提出了一些新的概念和技术来应对这些挑战。这些包括通过可重构振荡器的多共振模式开关和相变，具有原位统计线性化的时间-数字转换器，合成器模拟组件的实时数字辅助以及内置监控，自适应和自检电路。将设计和制造CMOS原型来验证这些概念。更广泛的影响本研究的结果将满足实现实用设备的关键需求，这些设备将使用先进的频谱接入技术用于未来的无线系统。这些成果还将满足近期对原型机的迫切需求，这些原型机将成为试点试验台的基础。该提案的教育组成部分包括科学出版物、公共关系、指导和通过CMU盖尔芬德服务学习和推广中心开展的各种项目进行的推广；这些项目包括为中学女生提供的“第4次进入工程”和“暑期工程体验”项目，以及为女性和其他代表性不足的群体提供的其他拓展项目。这项研究的成果将被整合到PI教授的各种课程中。将开设一门新的“混合信号集成电路设计”课程。PI将继续通过卡内基梅隆大学暑期研究体验项目招收和培训本科生，特别注重吸引少数群体和机构的学生。

Wireless communication has had an immeasurable economic, societal and scientific impact worldwide. However, with the recent explosion of smartphones and tablets, and the expected emergence of new types of networks such as sensor swarms and the internet of things, the current model of licensed access to spectrum being appears increasingly unviable. There is currently active research into two complementary solutions: (1) spectrum sharing cognitive radios and (2) wireless networks based on dense, short-range millimeter-wave links. The development of highly reconfigurable, power-efficient radios is critical to the long term success of these technologies. This proposal addresses a critical circuit-level challenge by developing design techniques for agile, spectrally pure and reconfigurable "universal" frequency synthesizers. Intellectual Merit: Compared to analog-based frequency synthesizers commonly used in current radios, all-digital frequency synthesizers are less sensitive to the analog-imperfections of nanoscale CMOS, are highly reconfigurable and can be rapidly ported across technology nodes, and are therefore promising candidates for universal frequency synthesis. However, the design of widely tunable oscillators, high-resolution/high-linearity time-to-digital converters and the interface between the two pose obstacles to the successful realization of all-digital frequency synthesizers. Several new concepts and techniques are proposed to address these challenges. These include multi-resonance mode switched and phase-change via-reconfigurable oscillators, time-to-digital converters with in situ statistical linearization, real-time digital assistance for the analog components of the synthesizer and built-in monitoring, adaptation and self-test circuitry. A CMOS prototype will be designed and fabricated to validate these concepts. Broader Impact The outcomes of this research will fill a critical need towards the realization of practical devices for use in future wireless systems using advanced spectral access technologies. The outcomes will also fill a pressing near-term need for prototypes that form the basis of pilot testbeds. The educational components of this proposal include scientific publications, public relations, mentoring, and outreach through various programs conducted by the CMU Gelfand Center for Service Learning and Outreach; these programs include the Moving 4th into Engineering and Summer Engineering Experience for girls in middle school programs and other outreach programs for women and other underrepresented groups. The outcomes of this research will be integrated into various classes taught by the PI. A new capstone course on Mixed-Signal Integrated Circuit Design will be developed. The PI will continue to recruit and train undergraduate students through the the Summer Research Experience Program Carnegie Mellon, with a special focus on attracting students from minority groups and institutions.