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FIBER–WIRELESS (FIWI) NETWORKS: TECHNOLOGIES, ARCHITECTURES, AND FUTURE CHALLENGES
4.1 INTRODUCTION
We are currently witnessing a strong worldwide push toward bringing optical fiber closer to individual homes and businesses, leading to fiber to the home/fiber to the premises (FTTH/FTTP) networks [1]. In FTTx networks, fiber is brought close or all the way to the end user, where x denotes the discontinuity between optical fiber and some other, either wired or wireless, transmission medium. For instance, cable operators typically deploy hybrid fiber coaxial (HFC) networks where fiber is used to build the feeder network while the distribution network is realized with coaxial cables. Another good example for wired fiber-copper access networks are hybrid-fiber twisted-pair networks that are widely deployed by telephone companies to realize different variants of digital subscriber line (DSL) broadband access solutions.
From a capacity point of view, one might seriously argue that there is no techno-economic need and justification to replace hybrid-fiber twisted-pair-based DSL networks with all-optical solutions—for example, passive optical networks (PONs). According to Cioffi et al. [2], the so-called copper-PON (CuPON) multidropping DSL architecture is able to provide 50 Gbit/s of shared bandwidth in each direction on existing twisted pair of copper telephone lines through exploitation of all modes of crosstalk. Thus, CuPON is able to offer much ...
