By Dr. Timothy Brophy, Dr. Robert Howald, Curt Smith, General Instrument Corporation, Transmission Network Systems
The move toward headend consolidation, coupled with the evolution of the traditional CATV HFC network into a two-way interactive data communications platform, has led to an investigation of optimal architectures. The goals of such architectures are clear. They must meet current needs of multiplexed analog and digital systems and provide a straightforward and cost-effective migration. As a utopian objective, it should provide the ability to handle the maximum capacity anticipated, as two-way interactive services continue to expand in the longer term.
This latter aim, commonly referred to as ''future-proofing, " is much more difficult to pin down. The highly variable nature of potential service offerings, and the inability to predict the likelihood of their acceptance makes achieving this goal challenging. However, it is commonly accepted that increased use of optics and the efficient use of the RF bandwidth are the enabling network technologies to assure these goals are met. In this paper, we will discuss today's freshest technologies, DWDM and frequency stacking.
As a result of the need for more bandwidth in both upstream and downstream paths, optical and RF technologies have advanced. Today, DWDM systems are being deployed to provide segmentation and increased bandwidth. Additionally multiplexing in the RF domain is also being used in the upstream pass-band to increase bandwidth efficiency. From a network planning perspective, both DWDM and frequency stacking are excellent tools for "future-proofing" a network. The focus of this paper will be the combination of these technologies. Questions to be answered are:
Will it work? How does it help my network? How does it compare with other options?