NeTS: Small: Networking at Terahertz Frequencies

对无线带宽的需求每年都在快速增长，预计将继续增长。预计未来10年内，每个用户的无线带宽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情况至少高出两个数量级。推动对带宽需求的不断增长的应用非常多样化。从消费者的角度来看，关键驱动因素包括超高清电视等应用的发展，而在商业领域的应用包括将数据中心中的数十万台计算机联网，或为医疗和其他类似应用提供非常高质量的多媒体。该项目旨在利用无线频谱中相对未开发的部分，以太比特/秒的速率传输数据。所讨论的频谱被称为太赫兹频谱，频率从300 GHz延伸到3.1 THz。在太赫兹频谱上提供太比特数据速率的挑战很多，从对这些频率下的通信的有限理解到利用可用于建立通信链路的巨大带宽，再到理解这些频率下的网络。该项目将提供一些较大的开放问题的答案，包括信道特性和调制实现太比特率。由于所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，因此今天用于高速通信的技术在逻辑上不能外推到太赫兹频带。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，每秒可以传输太比特的信息，同时使用相对较慢的时钟和廉价的设备。这种技术的可行性将进行系统的研究，首先进行详细的太赫兹信道测量，然后在这些频率的信道脉冲响应模型的发展。这些测量将考虑到一个小房间的距离，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。该项目将测量结果与详细的模拟相结合，回答有关使用这些类型的脉冲时预期信道容量的问题。在这些研究的同时，该项目将在不同的距离和环境条件下对脉冲行为进行实验表征。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，并将为太赫兹通信系统的未来发展铺平道路。这项工作的更广泛影响范围从根本上影响无线通信的研究方向，以促进下一代通信新技术的发展。此外，作为该项目一部分开发的太赫兹测量数据库将向公众公布，并将成为更广泛的科学界的宝贵资源。该项目还将通过开发新课程和让学生参与测量来加强对未来劳动力的培训。最后，这项工作的成果（兆兆位/秒的数据传输）将最终影响信息在家庭和工作场所的传输方式。

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.