By Richard S. Prodan, Mukta Kar, and Majid Chelehmal, Cable Television Laboratories
Compression technology, coupled with advances in digital modulation, has many advantages over its analog counterpart, most notably efficiency and flexibility in bandwidth utilization. MPEG standardization, MPEG-2 in particular, has been the key ingredient for interoperability and has been the catalyst in the widespread acceptance of digital audio/video (A V) technology. These factors have contributed to the transmission/broadcast of multiple standard definition television (SDTV) signals, or one high definition television (HDTV) signal, over a single 6-MHz channel. The advantages of digital technology are merging telecommunication services, computing, and digital A V industries into multimedia, where digital video will play a dominant role. New multimedia applications are evolving every day. Even though digital technology has expanded the transmission efficiency, the addition of new applications and services for delivery to homes and businesses will bring new challenges to the cable and broadcast industries. Most of these challenges can be facilitated by an efficient use of the transmission spectrum. We believe that rate-remultiplexing technology can address the issue of optimal utilization of available bandwidth using compressed digital video delivery.
This technology has been researched at CableLabs over the past two years. In this paper, rate-remultiplexing techniques will be analyzed, and their corresponding advantages and disadvantages will be discussed. The implementation of this technology in hybrid fiber coaxial (HFC) cable networks for efficient spectrum management will be discussed in detail. Finally, development activity and the current availability of equipment utilizing rate-remultiplexing will be discussed.