ABSTRACT
Optical wireless communication is rapidly becoming a familiar part of modern life [1, 2]. Over the last decade, there has been a steady increase in the number of consumers requiring high-capacity links. In the past, these customers were pleased with tens of megabits per second; but nowadays near-gigabits-per-second links are required. Banks, universities, offices, companies, and government facilities all need communication services for stationary and mobile applications. (The emerging technology of mobile optical wireless communication is beyond the scope of this book and will not be discussed in this chapter.) High-data-rate communication applications range from next-generation Internet and support for cellular infrastructure to last-mile applications. Some of the requirements of these new applications could be met by fiber optics or millimeter-wave wireless links. Fiber optics has been distributed in many cities in close proximity to the backbone of the network. However, a massive effort is required to bridge the distance from the central switch to the client premises (this is termed the “last mile” problem), and many difficulties need to be overcome. In some cases it may not be possible or practical, or it may be too time consuming or costly to dig up main streets and lay down fibers. In such cases a wireless solution can bridge the gap. Millimeter-wave wireless links provide medium data capacity for long ranges. However, the capacity is limited, and in some cases public health and safety considerations as well as heavy tariffs and licensing fees make this selection less favorable. Additionally, the bureaucracy involved in obtaining permits can take months. As a result, in cases where high data rate is required without any licensing and tariffs and the range is limited, optical wireless communication (OWC) is the best solution (Figure 4.1).
