RF transport over optical fiber in urban wireless infrastructures [invited]

The technology for transport of RF signals over optical fibers at long (metropolitan-scale) distances which enables today's hybrid fiber/coax networks for community antenna TV and cable modem access is being leveraged for coverage and capacity enhancements in wireless networks providing affordable anywhere/anytime services. This is particularly important in high-traffic urban and in-building arenas where RF propagation is challenging. A hybrid Fiber/Cable (HFCa) approach utilizing legacy urban cabling infrastructures is shown to be highly cost effective, since the installation cost (which often dominates over equipment cost) is greatly reduced or eliminated. Optimum HFCa system architectures are discussed in this paper with Ca = C (coax) and C5 (Cat-5 unshielded twisted pair cables) for outdoor urban/metropolitan and indoor/in-building arenas, respectively. The general results in this paper apply to both. A quantitative evaluation of capacity gain by traffic trunking in a distributed antenna system is given. All-fiber RF transport for remote radio head systems serving outdoor metropolitan areas is briefly discussed.