In the preceding chapters, we witnessed that optical fiber is widely used as the transmission medium of choice in wide, metropolitan, access, and local area (wired) networks. Passive optical networks (PONs) might be viewed as the final frontier of optical wired networks where they interface with a number of wireless access technologies. One interesting approach to integrate optical fiber networks and wireless networks are so-called radio-over-fiber (RoF) networks. In RoF networks, radiofrequencies (RFs) are carried over optical fiber links to support a variety of wireless applications. In this chapter, we describe some recently investigated RoF network architectures and their support of various wireless applications. After reviewing the use of optical fiber links for building distributed antenna systems in fiber-optic microcellular radio networks, we elaborate on the various types of RoF networks and their integration with fiber to the home (FTTH), WDM PON, and rail track networks.

Fiber-optic microcellular radio

Distributed antenna system

To increase frequency reuse and thereby support a growing number of mobile users in cellular radio networks, cells may be subdivided into smaller units referred to as microcells. The introduction of microcells not only copes with the increasing bandwidth demands of mobile users but also reduces the power consumption and size of handset devices. Instead of using a base station antenna with high-power radiation, a distributed antenna system connected to the base station via optical fibers was proposed in Chu and Gans (1991).