Planning and Engineering for Remote Line Power

Network Access Whitepaper


Telecom network elements, both wireline and wireless, continue to move closer to the end user to meet bandwidth needs. From Fiber-to-the-Home (FTTH) and Digital Subscriber Line (DSL) in wireline networks to Distributed Antenna Systems (DAS) and small cell wireless networks, the network trend is to move from a centralized to a distributed architecture. Since they serve fewer users, the network elements require less power per location, but the number of sites increases exponentially. The sheer number of sites makes it difficult for the power utility companies to meet the communications service provider’s turn-up dates. Moreover, the low power consumption per location provides little incentive for the utility to accelerate construction to meet the communications service provider’s deployment plans.

This trend toward distributed networks has led to the increased use of Remote Line Power (RLP) as an alternative means of energizing the remote devices. With RLP, the service provider delivers power to each device over copper cables that originate from a centralized location. Sometimes the copper cables come from excess capacity in existing Outside Plant (OSP) networks. In other cases, such as small cell networks, the service provider lays new copper cables in conjunction with the fiber backhaul cable that connects each site. Either way, the communications service provider controls its destiny.

Deployment of Remote Line Power networks changes some of the practices and processes for planning and engineering. The copper cables that typically supplied -48Vdc power for POTS now deliver ±190Vdc. Both -48Vdc and elevated voltage cable pairs may be included in the same cable and sometimes the same binder group. Reach is affected due to the size of the load and the use of higher voltages. And the presence of the elevated voltage necessitates additional precautions to ensure technician safety.

This paper addresses the new planning and engineering requirements for RLP networks. It provides details on how RLP works, how far it can reach, and how to qualify cable pairs for use in these circuits. The paper concludes with recommendations for best practices for deploying Remote Line Power.

Examples of distributed networks that are often powered by RLP include:

  • Fiber-to-the-Home (FTTH) networks, with a single copper pair and down-converter delivering power to the Optical Network Termination (ONT) units located at the customer’s premises
  • G.Fast networks, with the copper pairs and a sealed down-converter energizing the Distribution Point Unit (DPU) located within a few hundred meters of the customers served
  • Fiber-to-the-Node (FTTN) networks, with 2-3 cable pairs supplying power directly to small 12- and 48- channel VDSL2 DSLAMs that have built-in downconverter circuitry
  • Small Cell networks, with 2-4 cable pairs and one or two sealed down-converters supplying power to the small cells deployed much closer to customers than Macro Cells