By G. Keith Auzenne, Charter Communications; Esteban Sandino, Charter Communications; Diana Linton, Charter Communications
Operators worldwide are working through the 10G initiative and are in the process of developing and deploying scalable, cost-effective technology platforms to power future 10G wired networks. These efforts are coupled with physical network upgrades to leverage today’s nearly ubiquitous Hybrid Fiber Networks (HFC) deployed throughout the world. The ultimate goal is to support delivery of 10G services and enable new immersive digital experiences over low-latency, reliable and secure connections at speeds of 10 Gbps. The introduction of DOCSIS 3.1 and DOCSIS 4.0 have given operators the ability to move towards the path to 10G. This paper outlines Outside Plant (OSP) architectural, technical, and physical challenges that must be addressed when designing the next generation of HFC networks to achieve higher split orders, greater speeds and increased bandwidth capacities. The importance of leveraging the existing HFC infrastructure and maintaining legacy RF levels below 1.8 GHz, and why this is crucial during the design process, will be explained. In addition, we will focus on the importance of managing total composite power (TCP) and other performance indicators when operating higher powered 1.8 GHz hybrids and amplifiers. And the importance of full spectrum RF levels, tilts and step-downs, to ensure best performance while minimizing distortions, will also be discussed. Through much research, extensive design specification creation and experimentation coupled with network modeling over more than 30 years, one thing stands out; the design process is one of the most important phases of proposed outside plant upgrades. It is true that HFC networks are thought of as forgiving. Meaning, even though the spacing of actives from past bandwidth expansions may have been pushed to or past the limits of their capability, somehow the networks continue to deliver. With 1.8 GHz upgrades, this tolerance to compromised networks is greatly reduced. Performance and distortion parameters are more critical. Insertion and attenuation losses at such high frequencies accumulate much more rapidly. Well tested design specifications and the adherence to them at 1.8 GHz becomes more crucial to ensure healthy, bi-directional 10G capable networks.