HFC networks are the likely candidate for wireless/wireline convergence, and with continued roll outs of power cabling in fiber networks, they can stay that way.
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As wireless networks continue to expand, the telecommunications industry has been discussing wireless/wireline convergence. Cable operators, however, have been using converged networks for years. MSOs have been converging their hybrid fiber coax fixed wireline service with Wi-Fi wireless services by deploying tens of thousands of hot spots. In addition, MSOs have enacted mobile virtual network operator licenses and are actively bidding on wireless spectrum. They are also leasing their networks for small cell backhaul to telecom operators. In the MSO world, wireless/wireline convergence has a very broad meaning and HFC networks are uniquely suited to such convergence.
This article explores the advantages of the HFC network for wireless/wireline convergence when it comes to deploying small cells for LTE and 5G networks.
Why HFC networks are ripe for convergence
HFC is the network of choice for cable companies around the world. In an HFC network, signal passes over fiber and then to coaxial cable for delivery to subscribers. In the coax portion of these networks, the signal must be amplified approximately every 2,500 feet, which requires an amplifier that needs power. In the early days of MSO networks, the networks consisted exclusively of coaxial cable, and it was frequently necessary to insert a dozen or more amplifiers between the signal source and the subscriber. To power those amplifiers, MSOs provided power within the coax on the same conductors as their RF distribution in their networks.
Amplifiers create noise, however, and an amplifier failure could cut off service. MSOs looked to fiber to improve signal quality and reliability. Driving fiber out into the network reduced the number of amplifiers required (so that in today’s networks, most subscriber links have only one or two amplifiers in them), but it also required the deployment of fiber nodes where the signal could be converted from fiber to coax. These nodes also require power, so MSOs have continued to run power in their networks alongside fiber within the coax.
Now, MSOs are driving fiber farther out toward the edges of their networks. MSOs have been offering data services over their networks for nearly 20 years. In fact, data service, not video, is now the major cash cow for MSOs. This has led to an effort to drive fiber deeper into the network since fiber can deliver far more bandwidth than coaxial cable. Today, there are basically three drivers behind the move to more fiber: improved quality of service, higher reliability and higher bandwidth for data services.
Why HFC networks excel at wireless convergence
Network densification and the march to “5G” technology will lead to deployments of small cells on a massive scale. By some estimates, a 5G network will require small cells 100 meters apart. HFC networks are perfect for small cell/5G deployment for three reasons: backhaul (fiber in 80% of the HFC network; location (small cells must be ubiquitous, and the HFC network goes everywhere; and HFC networks have power throughout 80% of the network plant. (approximately 90 volts AC, 15 amps).
Legacy telephone infrastructure doesn’t provide power in their passive optical networks. To deploy small cells a telephone company must have the power utility dig a trench and run power to every small cell. This requires not only trenching but appealing to the local power company to install a meter and then hiring an electrician to install a power outlet. This is an expensive process and it delays time to market because utility companies move slowly. To overcome these issues telephone companies are currently contracting with MSOs to deploy connectivity and power for small cells.
Maintaining the HFC advantage in a 5G world
When it comes to wireline/wireless network convergence, MSOs are at a great advantage over traditional telecommunication operators because of the amount of available power in their networks, the amount of bandwidth in their networks and availability of small cell real estate. To maintain this advantage MSOs should continue to deploy power conductors as they roll out more fiber in their networks.
There will be plenty of reasons why power will be required in future networks. 5G networks will require more electrical devices, not fewer. Consider fixed wireless 5G, which will be the first to be deployed. Wireless companies face the same challenges in powering fixed wireless sites as they do powering small cell sites and HFC networks offer the same advantages. However, in most cases it will be necessary to run a dedicated fiber cable to fixed wireless nodes because fixed wireless will use millimeter wave spectrum that requires more power and bandwidth. In contrast, installers can simply pull power and connectivity from a passing HFC network to light up small cell sites.
MSOs don’t yet know if they’re going to end up competing with wireless providers or if they’ll end up leasing assets to wireless providers. But they know their networks are going to be what carries it. HFC networks are the likely candidate for wireless/wireline convergence, and with continued roll outs of power cabling in fiber networks, they can stay that way.
John Chamberlain is a director in the office of the CTO at CommScope, responsible for understanding the market environment and technology trends that influence product development. Most recently, his focus has been on convergence of wireless and wireline networks, including power consumption, 5G fixed and mobile wireless deployment, OSP physical location and remote reconfiguration technologies and passive component hyperscale data center evolution. At CommScope, he previously ran product management for the Broadband Products group including 75 ohm and products and introduced CommScope fiber optics product lines to the industry. He also owned telecommunications OEM companies including Norscan and Broadband Technologies. Chamberlain is a “Ramblin’ Wreck” from Georgia Tech.
