Indoor optical wireless communication systems for broadband access

在宽带服务方面，加拿大是世界领先的国家之一。然而，2008年经济合作与发展组织的一项研究表明，许多国际竞争对手正在侵蚀宽带普及率方面的初步领先地位。宽带普及率的一个重要因素是是否有合适的接入方法。该研究计划开发新的通信理论、算法和原型，以提高室内宽带光学无线链路的速率和可靠性。这些链路通过调制和检测光强度来传输数据，并提供高速率、低成本、无干扰的室内通信。特别地，本研究考虑了可见光和红外波长的室内光通道。可见光通信（VLC）通道采用白光照明led，其能源效率至少是白炽灯泡的十倍。白光led的一个经常被忽视的特点是有显著的调制带宽。廉价的基于磷的白光led的带宽超过20MHz，而RGB led的带宽可以超过100MHz。虽然其他人已经考虑将白光led用于照明和通信，但这些链路的严格通信理论，算法和调制的发展很少。这项工作将为室内VLC信道开发频谱高效信号，以提高可用数据速率，重点关注三种主要方法(i)光学MIMO技术，（ii）带宽高效调制和（iii）均衡方法。一个独特的特点是将调光和色彩选择融入到现代设计问题中。此外，VLC链路必须与电力线调制解调器集成，电力线调制解调器将传输数据以允许在房间内进行无线访问。在红外波段，高速动态光斑扩散（DSD）红外通信系统将被研究。估计表明，当使用成像接收器时，这种链路的数据速率可能超过1Gbps。将开发容量最大化路径适应和短长度无速率码设计。该研究计划将利用我们实验室现有的硬件来开发原型，以验证开发的算法。

Canada is among the leading nations in terms of access to broadband services. However, a 2008 OECD study indicated that many international competitors were eroding this initial lead in broadband penetration. An important factor in broadband penetration is the availability of suitable access methods. This research program develops new communications theory, algorithms and prototypes to improve the rates and reliability of indoor broadband optical wireless links. These links transmit data by modulating and detecting an optical intensity and provide high-rate, cost effective, interference-free indoor communications. In particular, this research considers indoor optical channels at both visible and infrared wavelengths. Visible light communication (VLC) channels employ white illumination LEDs whose energy efficiency is at least ten times greater than incandescent bulbs. An often overlooked feature of white LEDs is there significant modulation bandwidth. Inexpensive phosphor-based white LEDs have bandwidths in excess of 20MHz while RGB LEDs can have bandwidths in excess of 100MHz. While others have considered using white LEDs for illumination and communications, there has been little development of rigorous communication theory, algorithms and modulation for these links. This work will develop spectrally efficient signalling for indoor VLC channels to improve the available data rates focusing on three main approaches (i) optical MIMO techniques, (ii) bandwidth efficient modulation and (iii) equalization methods. A unique feature is the integration of dimming and colour selection into the modem design problem. In addition, VLC links must be integrated with power-line modems that will deliver data to allow wireless access in a room. At infrared wavelengths, high-speed dynamic spot diffusing (DSD) infrared communication systems will be investigated. Estimates indicate that data rates in excess of 1Gbps are possible in such links when imaging receivers are employed. Capacity maximizing path adaptation and short-length rateless code design will be developed. This research program will leverage existing hardware in our lab to develop prototypes to validate the developed algorithms.