Powering the last mile: an alternative to powering FITL

Many telephone Local Exchange Carries (LECs) and cable Multiple System Operators (MSOs) have experimented or deployed Fiber Distribution cable. Whether placing an Optical Network Unit (ONU) within 3000 feet of each subscriber or on the side of the house, these LECs and MSOs are demanding the most economical deployment architecture to serve their subscriber base with the greatest bandwidth possible. Since the 1980s, principally the LECs have deployed remote terminal (RT) sites in each and every feeder route in their network. Many of these sites are already fed by fiber. These fiber-fed RTs in the outside plant marked the first major encounter with having to provide remote power and associated battery backup in the outside plant. Usually, the powering architecture for these RTs has consisted of a -48-Vdc rectifier system connected to a -48-Vdc battery bus, all housed in a metal cabinet or concrete hut/CEV. As the quantity of RT sites undergoes rapid growth, and as the powering requirements for the ONUs hosted by these RTs also increase, other powering architectures, including network, or centralized powering, offer potential advantages. This paper discusses a powering architecture where a power node is located together on the same casement and pad as the RT. Compared to conventional powering, this co-located power node and RT allow a dramatic increase in the quantities of ONUs which may be hosted by an RT as well as many other advantages. This co-located power node may also be configured to provide 60/75/90 Vac power for HFC networks, out of the same power node.