Multiplexing Techniques for Scalable Wireless Interconnects at sub-THz Frequencies: Circuits-EM-Communication Codesign Approach

太赫兹频率下可扩展无线互连的多路复用技术eccs - 1408490pi: Kushik Sengupta，普林斯顿大学该提议旨在研究和开发亚太赫兹频率下无线互连的空间多路复用架构，作为每秒1太比特（1 Tb/s）的可扩展节能解决方案。随着我们进入超大规模计算时代，这些处理器处理大量数据将需要非常大的带宽，而目前电或光互连解决方案都无法满足这一需求。目前将电气互连扩展到更高数据速率的方法，要么受到可用带宽密度（Gb/s/mm2）、能源成本、通过长且有损耗的物理走线驱动高速数据的电路复杂性的限制，要么受到在受限的外形因素中可能容纳的最大并行物理走线数量的限制。太赫兹频率附近的无线互连很有前景，但10Gb/s的无线数据速率和高能量/比特要求，远远不能满足未来片外互连的带宽要求。在本提案中，我们的目标是研究使用通信理论的空域复用技术将信道容量增加许多倍的技术。在相同的总功率限制下，这种架构具有数量级的通道容量，从而为无线Tb/s互连提供了可扩展的解决方案。该方案的一个关键部分是将高频电路、系统和天线与通信理论技术无缝结合，以提高容量和数据速率的数量级，否则在单一方向分区的方法中是不可能的。印制电路板（PCB）上的金属互连走线是最常用的芯片互连方法。然而，在专门的服务器系统、高性能计算甚至便携式设备中，为了处理越来越多的数据，对计算能力的需求日益增长，这就要求从处理器到外设的通信数据速率按比例缩放。在大多数情况下，输入输出引脚的数量受到外形因素的限制，这对所有处理器之间的通信能力造成了瓶颈。在本提案中，我们研究了使用位于太赫兹频谱部分（微波和红外线之间）的高频电磁波在芯片组之间建立无缝无线通信链路的技术。移动到如此高的频率使我们能够利用维持如此高的数据速率所需的数量级更高的带宽。此外，我们研究了在短距离通信设置中通过空间复用技术以另一个顺序增加通信链路容量的技术。该项目的成功有望为从高性能计算到互联网数据中心的各种应用带来新型智能互联解决方案。这项研究工作的结果也有望对推进太赫兹电子领域产生重大影响，使成像和传感等各种应用受益。从更广泛的角度来看，这将对通信和计算领域的全新技术产生重大影响，这不仅使我们成为一个联系更加紧密的社会，而且还将推动应用科学其他领域的研究。这项研究也有望培养多学科领域的研究生和本科生，这对解决未来具有挑战性的研究问题至关重要。

Multiplexing Techniques for Scalable Wireless Interconnects at THz FrequenciesECCS-1408490PI: Kushik Sengupta, Princeton University This proposal aims to investigate and develop spatially multiplexed architectures for wireless interconnects at sub-THz frequencies as scalable, energy-efficient solution towards one terabit per second (1 Tb/s). As we enter the era of terra-scale computing, massive amounts of data crunching by these processors will require inordinately large amount of bandwidth, not currently served by either electrical or optical interconnect solutions. Current methods of scaling of electrical interconnects to higher data rates are either limited by the available bandwidth density (Gb/s/mm2), energy cost, the circuit complexities in driving high-speed data through the long and lossy physical traces, or by the maximum number of parallel physical traces possible to accommodate in a constrained form factor. Wireless interconnects near THz frequencies are promising , but wireless data rates of 10Gb/s and the high energy/bit requirement, falls way short of meeting the bandwidth requirements for future off-chip interconnects. In this proposal, we aim to investigate techniques where the capacity of the channel can be increased many-fold using communication theoretic spatial-domain multiplexing techniques. Under the same total power constraint, such architectures have orders of magnitude more channel capacity, thereby providing a scalable solution towards wireless Tb/s interconnects. A key component in this proposal is to combine seamlessly, high-frequency circuits and systems and antennas with communication-theoretic techniques to increase capacity and data-rates by orders of magnitude, not otherwise possible in a single directional partitioned approach. Metal-based interconnect traces on printed circuit boards(PCB) serve as the most common method of chip-chip interconnects. However, increasing need of computational power to crunch more and more data in specialized server systems, high-performance computing or even portable devices, requires that communication data-rate from the processor to the peripherals be scaled proportionately. In most cases, the number of input-output pins is limited by the form factor, which puts a bottleneck on communication capacity among all the processors. In this proposal, we investigate techniques to use very high-frequency electromagnetic waves located in the Terahertz portion of the spectrum (between microwaves and infra-red) to establish seamless wireless communication links among the chipsets. Moving to such high frequencies enables us to exploit orders of magnitude higher bandwidth needed for sustaining such high data rates. Additionally, we investigate techniques to increase the communication links capacity by another order through spatial multiplexing techniques in a short-range communication setting. The success of this project is envisioned to bring new forms of smart interconnect solutions for a host of various applications from high-performance computing to internet data centers. The results of this research effort are also expected to have major impact in advancing the field of THz electronics benefitting diverse applications such as imaging and sensing. In a broader vision, this will have major impacts in radically new technologies in communication and computation, which not only makes us a more connected society, but also fuel research in other areas of applied science. This research is also expected to train both graduate and undergraduate students in multi-disciplinary fields, which are vitally important for solving challenging research problems for the future.