Monga

Fiber Access Network

A Cable Operator’s Perspective



by
John A. Brouse, Jr.
Director of Network Implementation
Charter Communications, Inc.



Introduction

During the late 1980s, cable television operators in the United States reached a critical point where bandwidth demands and physical extensions to their coaxial-based, tree and branch service delivery networks stressed thetechnical limits for signal quality and platform reliability. In response to the cable operators’ demand for a solution that addressed both signal quality and reliability, the industry looked toward adapting existing fiber optics technologies to accommodate frequency division multiplexed analog video distribution. The initial application of broadband fiber based platforms was targeted to simplyreduce the cascading effects of active electronic devices. Within a short time, the cable industry migrated fiber beyond this initial application and considered other services beyond traditional broadcast video. As other economic forces emerged, such as the launch of direct broadcast satellite service and the threat of telcos entering the video market, cable operators recognized the need toevolve their networks to support two-way interactive services and growing customer expectations. The result was development of a hybrid network which integrated fiber optic cables and devices with coaxial cables and RF based devices as a function of service based network requirements. This architecture was named the Hybrid Fiber-Coax (HFC) network and moved fiber closer to the customer, usuallysupporting service groups of 500 homes or less. The current list of services which the cable television multi-system operator (MSO) is offering include traditional video entertainment, video on demand, high speed connections to the Internet, local and long distance telephony, with many more in development. While deployment of the HFC network has certainly been the principal enabler for these high endtwo-way services, it has not adequately addressed nor resolved other operational issues now coming to the forefront. Today’s two major concerns are

❑ escalating outside plant operation and maintenance costs negatively impacts cash flow growth
❑ evaluating and readying outside plant for new service launches negatively impacts product time-to-market





The Hybrid Fiber-CoaxNetwork


Those unfamiliar with the MSO’s services delivery platform often assume that the introduction of fiber into the outside plant meant a reduction in the amount of coaxial cable used. This is not the case. The initial deployment of fiber in the distribution network was the addition of fiber cables overlaid on the existing coaxial cables. The result was more cable to contend with notless. In fact, there are some HFC variations that increased the amount of coaxial cables used rather than reducing it. The focus then was on being able to reduce the number of customers sharing a given amount of bandwidth for both the downstream and upstream portions of the RF spectrum. As these serving areas became smaller in size, the signal quality and service reliability immediately improvedas a result of there being less “things” between the signal source and the customer. However, as a cumulative effect, more elements were added to the network. As a direct result, both preventative and demand maintenance requirements increase; as well, more active devices are being added to the network resulting in ever-rising electric power consumption rates. The initial capital investmentrequirements for the coaxial portions of the HFC network have stabilized with very little room for lowering cost; the fiber based portions of the network will see some level of cost reductions but will have a negligible effect, at least in the near-term. The focus then, is on deployment costs and operations costs.

From the perspective of outside plant assessment and readiness to launch new...