STI: Multi-Hop Free Space Optics Last-Mile Networks Using Very Low-Cost Components

由于众所周知的“最后一英里”问题，互联网核心的带宽的巨大爆炸已经停止了对最终用户的需求，在这个问题上，传统上不可能获得通往家庭和企业的高带宽管道。“无光纤”或自由空间光（FSO）网络可以有效地补充基于非许可频谱RF的WLAN技术（如802.1 lb/a）和WMAN技术（如802.16），以解决“最后一英里”问题。自由空间光学为光谱的密集空间再利用提供了巨大的带宽和潜力。虽然光网络在有线网络世界中已经变得流行，但自由空间光学（FSO）仍然是一种利基技术，仅用于提供选定的点对点链路，而不是作为通用的城域网技术。此外，自由空间地面光通信的几个基本方面尚待探索。该提案是调查的基本限制非常低成本的组件，并创建通信系统，挖掘到FSO的高带宽潜力，同时解决其关键限制（例如：视线（LOS）的可用性，LOS发现，LOS对齐）。调查非常低成本的通信系统和多跳光网络使用高亮度可见光谱LED（HBLED），具有更有吸引力的传播空间复用特性相比，普通亮度红外LED。此外，基于LED的系统的潜在尺寸、重量、功率和形状因子方面将使其非常适合用于自组织基础设施（例如：气球、树梢、灯柱）。烟囱上的杆、移动的车辆等），以及新的应用，如高带宽移动的ad-hoc网络和未来的传感器网络。使用以1-10 mW功率实现100 Mbps的收发器对，该建议是使用数千个收发器到2维和3维空间结构（例如：2-D阵列、3-D球形/蜂窝结构）中的密集集成。2-D阵列将在1-2公里范围内提供极高的聚合带宽（100 Gbps或更高）。所提出的3-D球形结构（a.k.a.光学天线）与LOS自动发现和LOS自动跟踪技术相结合，以在LOS存在的情况下立即发现和跟踪LOS。这种结构将允许不间断的4，超高速操作，即使在高速摇摆（例如：120 mph，范围超过100米），甚至移动的条件下。该项目将建立低成本的FSO互连系统，补充相对便宜的和可编程的电子元件后，10 - 100的光电（OEO）跳。还建议研究利用特定空间结构（例如：二维阵列、球形等）在电子跳上的空间编码和冗余技术。基于FSO的固定和ad-hoc配置的基本网络容量限制，以及未来传感器网络中可实现的基本每比特功率的检查将完成。 评估这种多跳FSO网络对TCP/IP、VoIP和多媒体应用性能的影响。利用与著名互联网企业家的合作关系，现场试验了我们的低成本基于FSO的原型系统、现成的802.1 lx系统、IP路由和802. LD桥接协议将会出现。拟议的跨学科研究将为基于LED的通信、低成本的自由空间光网络以及在未授权频谱中部署最后一英里网络的模型做出重大贡献。NSF认识到需要解决丢失英里问题，并为该项目提供资金，希望该项目立即产生解决方案，或建立解决方案的新方向。

The tremendous explosion of bandwidth in the core of the Internet has stopped short of end-users due to the well-known "last-mile" problem where it has traditionally been infeasible to get a high bandwidth conduit to the home and businesses. "Fiberless" or Free Space Optical (FSO) networks can effectively complement unlicensed-spectrum RF-based WLAN technologies like 802.1 lb/a, and WMAN technologies like 802.16 for the "last mile" problem. Free space optics offers tremendous bandwidth and potential for dense spatial reuse of the optical spectrum. Although optical networking has become popular in the wired networking world, free space optics (FSO) is still a niche technology used to provide only selected point-to-point links, and not as a general-purpose metropolitan area networking technology. Moreover, several fundamental aspects of free space terrestrial optical communication are yet to be explored. The proposal is to investigate fundamental limits of very low-cost components, and create communication systems that tap into the high bandwidth potential of FSO, while addressing its key limitations (eg: Line-of-Sight (LOS) availability, LOS discovery, LOS alignment).An investigation of very low-cost communication systems and multi-hop optical networks using high-brightness visible spectrum LEDs (HBLEDs) that have more attractive propagation & spatial reuse characteristics compared to ordinary brightness infrared LEDs will occur. Moreover the potential size, weight, power and form-factor aspects of LED-based systems would make it ideal for use in ad-hoc infrastructures (eg: balloons, treetops, lampposts. poles on chimneys, moving vehicles etc), and novel applications like high-bandwidth mobile ad-hoc networks and future sensor networks may be found.Using trans-receiver pairs that achieve 100 Mbps with 1-10 mW power, the proposal is to use dense integration of thousands of trans-receivers into 2-dimensional and 3-dimensional spatial structures (eg: 2-d array, 3-d spherical/honeycomb structure). The 2-d array would provide extremely high aggregate bandwidth (100 Gbps and more) over 1-2 km. The proposed 3-d spherical structures (a.k.a. optical antenna) combined with LOS auto-discovery and LOS auto-tracking techniques to instantly discover and track LOS if it exists. This structure will allow uninterrupte4,jiltra-high-speed operation even in high velocity sway (eg: 120 mph, range over 100s of meters) or even mobile conditions.The project will build low-cost FSO interconnection systems, complemented with relatively cheap and programmable electronic components after l0s-l00s of opto-electronic (OEO) hops. It is also proposed to investigate spatial coding and redundancy techniques at the electronic hops taking advantage of the particular spatial structures (eg: 2d array, spherical etc). An examination of fundamental network capacity limits for FSO-based fixed and ad-hoc configurations, and fundamental power-per-bit achievable in future sensor networks will be done. Evaluating the impact of such multi-hop FSO networks on the performance of TCP/IP, VoIP and multimedia applications. Leveraging a partnership with renowned Internet entrepreneur, field trials of a mix of our prototype low-cost FSO-based systems, off-the-shelf 802.1 lx systems, IP routing and 802. ld bridging protocols will occur.The proposed inter-disciplinary research will make significant contributions to LED-based communications, low-cost free space optical networks, and models for deploying last-mile networks in unlicensed spectra.NSF recognizes the need to solve the lost mile problem and funds this project with the hope of a solution immediately emerging from this project, or new directions to a solution being established.