HFC cable-TV networks form Australian backbone
HFC cable-TV networks form Australian backbone
Last year, Australia`s state-owned carrier Telstra Corp. Ltd. and rival Optus Vision began rolling out multibillion-dollar hybrid fiber/coaxial-cable (HFC) systems that will provide pay-TV and form the backbone of the nation`s broadband, bidirectional full-service network. Last September, Optus began pay-TV services, and Telstra followed one month later with Foxtel Cable TV, a partnership between Telstra and News Corp. Ltd.
Telstra claims its HFC rollout is the fastest in the world, with more than 5000 homes passed each day. By the end of this year, 1 million homes will be passed, and by 1999, 4 million homes are expected to be passed. Philips is acting as systems integrator for the $4-billion project, which involves the installation of approximately 40,000 kilometers of cable in Sydney, Brisbane, Melbourne, Perth, Adelaide and the Gold Coast.
Contributing to the quick rollout are Australia`s high urbanization ratio (most of the nation`s 17-million inhabitants live in five major cities) and the rapid market acceptance by users of telecommunications and electronic devices (see Lightwave, June 1995, page 1).
Optus Vision, which is a joint venture of Optus Communications, Continental Cablevision and Publishing Broadcasting Ltd., claims to have the second-largest HFC rollout in the world. The partnership aims to pass at least 3 million homes by the end of 1996. The main goal, however, is to build a customer-access network that will end customer reliance on Telstra`s network, especially telephony. Bloomington, MN-based ADC Telecommunications Inc. is providing its Homeworx platform for Optus Vision`s HFC network. It is still unclear whether Optus sees the expensive pay-TV service being supported by the telephony component, or vice versa.
For both companies, the driving forces for the rollout include the pay-TV market as well as markets for broadband services such as high-speed Internet access via cable modems and video-on-demand. They also want to establish a mutually competitive position before the 1997 deregulation. After 1997, their ability to bypass local planning laws--enabling them to install cable without consulting local governments--may be curtailed and other competitors can enter the market. Neither company is expecting serious competition, however.
Australia`s HFC network is an analog transmission system that distributes identical signals from headends to city areas and allows bidirectional communications using a set of signals shared by 900 and 2000 homes in Telstra`s and Optus`s systems, respectively. From the exchange to the home, downstream and upstream signals move at 750 megahert¥through an electrical-optical-electrical process (see figure). Fiber cabling runs from an exchange to a fiber-serving area where nodes distribute the signals down streets via 15-millimeter coaxial cable. The 8-mm coaxial cabling is connected to homes via taps through existing conduits; new conduits are installed at a cost of A1000 (US$768) each to pass a home with 20-meter frontage.
Most cable-TV systems worldwide are installed above ground. However, Telstra prefers to install these systems underground, wherever possible. Bruce Warren, manager of Telstra`s national rollout project, expects that 15% to 20% of the network will go aerial, following the layout of existing infrastructure; for instance, if telephony is aerial, cable installation will also be aerial. Optus, on the other hand, is installing all cable on existing power poles. This strategy, however, continues to anger residents and local councils, who object to unsightly aerial pay-TV switches in their suburbs. In 1997, the company will face stiffer opposition from councils, so they are anxious to complete as much work as possible before then.
Existing underground infrastructure
The key element to Telstra`s cost-effective implementation of HFC networks is extensive use of existing underground infrastructure. The critical component of the design is to create up-to-date plans of the pit-and-pipe network, marked with features such as good network, blocked pipes and inadequately sized pits.
Telstra found that approximately 30% of older networks need upgrading because of small-diameter and blocked pipes. For blockages, high-pressure water jetting is one solution; for small-diameter pipes, the entire length can be bypassed with parallel boring.
One of Telstra`s goals is to deploy fiber-to-the-home or -curb. Also, 6-fiber nodes will be moved closer to customers as demand for digital connectivity increases, thus making the fiber-serving areas smaller. Both companies believe that the present hybrid system will be adequate for services that may be offered in the next five years.
The well-connected home in Australia in 1999 might include set-top units connected to a television and VCR, and a cable modem linked to a computer. The computer may have stereo sound and MPEG-2 video inputs from the set-top unit and the home sound system. Because high-definition television video-on-demand is probable within the next 10 years, the downstream bandwidth will need to be upgraded to at least 800 MH¥or 3.4 gigabits per second of user data--the equivalent of 150 high-definition TV channels--and in turn, will require a major redesign of the fiber-serving area.
Despite the speed with which Australia has established a national broadband network, the continent still faces some obstacles and uncertainties. According to the Australian Science and Technology Council, these could include inadequate competition for Integrated Services Digital Network provision with prices not falling rapidly enough; confusion over pay-TV options; consumer frustration because of the multitude of standards and services of variable quality; pay-TV, narrowband services and Internet growth; recurring network failures and not enough venture capital for telecommunications innovations. The small size of the Australian market in which to exploit economies-of-scale in production is also a factor. (Australia represents less than 2% of the global information and communications technology market.) q
Paul Mortensen writes from Australia and Japan.