NeTS: Small: Networking at Terahertz Frequencies

对无线带宽的需求每年都在快速增长，并且预计将继续增长。据估计，需求的年增长率从日本的71%到美国的117%以上不等。如果在未来10年实现这一增长，则意味着每个用户对无线带宽的需求将达到每秒数十千兆比特，这比大多数用户目前看到的带宽至少高出两个数量级。驱动如此无情的带宽需求的应用程序非常多样化。从消费者的角度来看，主要驱动因素包括超高清电视等应用程序的发展，而在业务领域，应用程序包括将数据中心中的数十万台计算机连接在一起，或为医疗和其他类似应用程序提供高质量的多媒体。该项目旨在开发无线频谱中相对未开发的部分，以每秒太比特的速率传输数据。所讨论的频谱被称为太赫兹频谱，频率从300千兆赫扩展到3.1太赫兹。在太赫兹频谱上传输太比特数据速率的挑战很多，范围从对这些频率上的通信的有限理解到利用可用的巨大带宽来建立通信链路，再到了解这些频率上的网络。该项目将提供一些更大的开放性问题的答案，包括通道表征和实现太比特速率的调制。目前用于高速通信的技术不能从逻辑上推断到太赫兹频段，因为涉及的大量带宽限制了设备，并且具有复杂的未知传播特性。该项目提出了一种利用太赫兹带宽制造脉冲的创新方法，每个脉冲都携带大量数据。因此，在使用相对较慢的时钟和便宜的设备时，每秒可以传输1太比特的信息。该技术的可行性将通过首先进行详细的太赫兹通道测量，然后在这些频率上开发通道脉冲响应模型，以系统的方式进行研究。测量将考虑到一个小房间的尺寸，并将作为太赫兹模拟器的输入，该模拟器将作为这项工作的一部分而建造。将测量结果与详细的模拟相结合，该项目将回答有关使用这些类型脉冲时预期信道容量的问题。与这些研究并行，该项目将实验表征脉冲在不同距离和环境条件下的行为。因此，该项目旨在填补我们对太赫兹通信的理解中的重要漏洞，并将为未来太赫兹通信系统的发展铺平道路。这项工作的广泛影响范围从根本上影响无线通信的研究方向到使下一代通信的新技术的发展成为可能。此外，作为该项目的一部分开发的太赫兹测量数据库将被公开，并将作为更广泛的科学界的宝贵资源。该项目还将通过开设新课程和让学生亲自动手测量，加强对未来劳动力的培训。最后，这项工作的结果（兆位/秒的数据传输）将最终影响家庭和工作场所的信息传输方式。

The demand for wireless bandwidth has been growing at a rapid pace every year and is expected to continue. Estimates of annual growth in demand range from 71% in Japan to over 117% in the U.S. Projecting this ahead a decade implies per-user wireless bandwidth needs of tens of gigabits per second, which is at least two orders of magnitude greater than what most users see today.Applications driving such a relentless thirst for bandwidth are quite diverse. From a consumer standpoint, key drivers include the evolution of applications such as ultra high-definition television while in the business domain applications include networking hundreds of thousands of computers together in data centers or delivering very high quality multimedia for medical and other similar applications. This project seeks to exploit a relatively unexplored part of the wireless spectrum to deliver data at rates of terabits/sec. The spectrum in question is called the terahertz spectrum and extends in frequency from 300 GHz to 3.1 THz.The challenges of delivering terabit data rates over the terahertz spectrum are many and range from a limited understanding of communication at these frequencies to utilizing the vast bandwidth available for establishing communication links to understanding networking at these frequencies. This project will provide answers to some of the larger open questions including channel characterization and modulation for achieving terabit rates. Techniques used for high speed communications today cannot be logically extrapolated to the terahertz band due to the massive amount of bandwidth involved which constrains devices and has complex unknown propagation properties. This project proposes an innovative way of exploiting the terahertz bandwidth to manufacture pulses, each of which carry large amounts of data. As a result, a terabit of information can be transmitted per second while using a relatively slow clock and inexpensive devices. The feasibility of this technique will be studied in a systematic way by first performing detailed terahertz channel measurements followed by the development of channel impulse response models at these frequencies. The measurements will consider distances of up to the dimensions of a small room and will serve as input to a terahertz simulator that will be built as part of this work. Using the measurements in conjunction with detailed simulations, the project will answer questions about the expected channel capacity when using these types of pulses. In parallel with these studies, the project will experimentally characterize pulse behavior over varying distances and environmental conditions. The project thus seeks to fill in important holes in our understanding of terahertz communications and will pave the way for future development of terahertz communication systems.The broader impact of this work ranges from fundamentally influencing research directions in wireless communications to enabling the development of novel technologies for future generation communications. Furthermore, the terahertz measurement database developed as part of this project will be made public and will serve as a valuable resource to the broader scientific community. The project will also enhance the training of the future workforce via the development of new classes and including students in hands on measurement. Finally, the outcome of this work (terabit/sec data delivery) will ultimately influence the way information is delivered in the home and in the workplace.