High-Efficiency Wireless Transmitters Employing RF Pulse-Width Modulation

采用RF脉宽调制的高效无线发射机Ranjit Gharpurey近几十年来，蜂窝电话和无线局域网（WLAN）等无线系统基础设施的增长以及通信设备的广泛可用性对现代生活的多个方面产生了深远的影响。这方面的例子包括商业，娱乐，医疗保健，导航，安全和安保，社交媒体，交通和工作场所的生产力，以及基本的人与人之间的沟通。 在可预见的未来，由“物联网”驱动的应用程序的出现，其中大量设备，如家用和工业电器，将需要无线连接，将对无线基础设施提出更高的要求。通信链路的功率效率，以及与诸如先进半导体工艺等技术的兼容性，这些技术能够实现小型化和低成本部署，对于无线系统的未来扩散至关重要。在移动的和固定设备中，效率对于最小化能量浪费都是重要的。随着未来几年可能部署数十亿个无线通信设备，对高效操作的需求实际上是根本性的。功率效率在移动的设备中也是至关重要的，因为它直接影响设备的可用操作时间。拟议的研究将通过利用先进的互补金属“氧化物”半导体（CMOS）工艺的创新架构，研究显著提高无线通信发射机效率的设计技术。该研究还将包括对发射机架构的研究，这些架构可以轻松地重新配置以在不同的终端环境中运行，以及减少发射机产生的杂散干扰的技术，这些干扰可能会降低其他设备的性能。 拟议的研究的一个关键部分将是脉宽调制（PWM）信令方案的调查，适用于无线发射机的问题。将探讨降低发射机频谱中噪声的技术。为了避免在时域中量化所引起的噪声，将研究模拟PWM技术。将采用用于直接在所需RF频带处高效生成PWM而不需要上变频的技术。这将有助于减少带外杂散，由于共存的考虑，带外杂散可能是上变频基带PWM的一个重大限制。将研究基于锁相环（PLL）的PWM发生器的使用，其允许产生高速模拟PWM。将研究使用高效的D类输出级以最小的重新配置来驱动宽带宽的输出负载。这样的发射机可以是诸如信道绑定之类的技术的使能器，其中，可以通过组合在多个频带上同时发送的数据流来将数据速率增加数倍。 一个实际的设计，以验证和验证所提出的电路技术将在一个现代的CMOS工艺实现。一个实际的无线系统，如4G-LTE将用于此调查。这项工作将成为一名研究生研究员博士研究的核心，他将获得无线发射机设计的理论，设计相关和实验方面的专业知识。

High-Efficiency Wireless Transmitters Employing RF Pulse-Width ModulationRanjit GharpureyThe growth in infrastructure for wireless systems such as cellular telephony and wireless local area networks (WLAN), and the widespread availability of communication devices, has had a profound impact on multiple aspects of modern life over the recent decades. Examples of this include commerce, entertainment, healthcare, navigation, safety and security, social-media, transportation and workspace productivity, in addition to basic person-to-person communication. In the foreseeable future, the emergence of applications driven by the "internet-of-things", wherein a significantly larger number of devices, such as household and industrial appliances, will require wireless connectivity, will place even greater demands on the wireless infrastructure. Power efficiency of communication links, and compatibility with technologies such as advanced semiconductor processes that enable miniaturization and low-cost deployment, will be critical to future proliferation of wireless systems. Efficiency is important in both mobile and stationary devices for minimizing energy wastage. With potentially billions of wireless communication devices being deployed over the coming years, the need for efficient operation is in fact, fundamental. Power efficiency is also critical in mobile devices since it directly impacts the available operating time of the device. The proposed research will investigate design techniques for significantly enhancing the efficiency of wireless communication transmitters through innovative architectures that leverage advanced Complementary Metal "Oxide" Semiconductor (CMOS) processes. The research will also include an investigation of transmitter architectures that can be easily reconfigured to operate in different end environments, and on techniques that reduce the spurious interference generated by transmitters, that can degrade the performance of other devices. A key part of the proposed research will be an investigation of Pulse-Width Modulation (PWM) signaling schemes, as applied to the problem of wireless transmitters. Techniques that reduce noise in the transmitter spectrum will be explored. To avoid the noise caused by quantization in the time-domain, analog-PWM techniques will be investigated. Techniques for efficient generation of PWM directly at the desired RF band without the need for frequency upconversion will be employed. This will help reduce the out-of-band spurs that can be a significant limitation in upconverted baseband PWM due to co-existence considerations. The use of phase-locked loop (PLL) based PWM generator, which allows for generation of high-speed analog PWM will be studied. The use of efficient class-D output stages to drive output loads over broad bandwidths with minimal reconfiguration will be investigated. Such transmitters can be an enabler for techniques such as channel-bonding, wherein data rates can be increased multiple-fold by combining data streams that are transmitted over multiple bands concurrently. A practical design to validate and verify the proposed circuit techniques will be implemented in a modern CMOS technology. A practical wireless system, such as 4G-LTE will be employed for this investigation. The work will form the core of the doctoral research of one graduate student researcher, who will gain expertise in theoretical, design-related and experimental aspects to the design of wireless transmitters.