Powering Outdoor Small Cells Over Twisted Pair or Coax Cables

One of the major obstacles to achieving routine deployment of small cells is the lack of generally available sources of power for the vast number of sites. Wireless service providers (WSPs) and neutral hosts design small cell networks based on RF coverage which, unfortunately, does not always coincide with an easily accessed source of power. Even when small cells are deployed on light poles, municipalities may not allow the wireless service provider access to the AC power present at the pole. An emerging solution to this problem is to power the sites using Network Power, wherein a centralized source of power is distributed to the small cell sites over copper cables. The Network Power solution typically consists of a source of power housed in an Outside Plant electronics cabinet that is equipped with power conversion devices, batteries (if backup is required), and OSP connection and protection to enable access to the copper cables. At the small cell site, a compact power conversion device is required to deliver the right voltage and power levels to the small cell. There are two different types of Network Power; Hybrid Fiber Coax (HFC) network using Coaxial Cable and Remote Line Power using Twisted Pair Copper Cable. For the past 40 years, Network Power using Coaxial Cables have been deployed by MSOs (Multiple System Operators) in the CATV industry to energize cascades of RF amplifiers and nodes for the coax portion of the HFC network. Similarly, wireline service providers have utilized Remote Line Power using Twisted Pair Copper Cables for powering Fiber-to-the-Home (FTTH) and Digital Subscriber Line (DSL) networks. The medium used to deliver Network Power whether it be twisted pair copper cable or coaxial cable is dependent on the network architecture and what is accessible to the service provider. Though wireless small cell service providers by their very nature do not have existing copper cables to deliver the power, Network Power is a viable option that is rapidly becoming the preferred method for meeting the providers' broad distribution plans and tight deployment schedules. There are three ways to address the lack of existing cables: (1) install new OSP copper cables alongside the fiber backhaul cable; (2) work with the local wireline carrier to use available capacity in its existing twisted pair copper network; and (3) work with the local cable TV company to use its existing coax cable network. The twisted pair copper cable and the cable TV coax cable require different power solutions to deliver the right voltage and power to the small cell, but the general concept is similar - deliver the right voltage and power to the small cell device(s) from a source located hundreds of meters away.This paper presents how Network Power works over both twisted pair and coax networks. It defines the network architectures for both approaches, as well as describes both the source and small cell power components. The paper concludes by summarizing the key attributes of each technique.