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12
NII Road Map: Residential Broadband
Charles N. Brownstein
Cross-Industry Working Team
Corporation for National Research Initiatives
The Cross-Industry Working Team (XIWT) is in the process of
examining how today's national information infrastructure (NII) can
evolve into the future NII envisioned in the XIWT white paper, "An
Architectural Framework for the National Information
Infrastructure." This paper presents the methodology the XIWT is
employing in this effort and some of the results obtained in
residential broadband. In this context residential broadband refers
to communications-based services using large amounts of access
bandwidth to provide NII services to residential users.
Methodology
To understand NII evolution, it is instructive to examine the
various overlapping and interdependent technology and business
segments making up the NII. Examples of these segments include
residential broadband, satellite-based communications, intelligent
transportation system, personal communications services, enterprise
networking, home automation, public telephony, electronic commerce,
and the Internet. Each of these segments will undergo important
evolutionary changes during the next decade. By piecing together
the evolutionary directions of these segments, a vision of the
overall NII evolution will emerge.
The initial portion of this study has not been to determine how
the NII should evolve, but rather to understand the current
technical and business directions of the various NII segments. No a
priori assumption was made that these segments would evolve in a
consistent fashion or that the result would meet the Clinton
administration's or industry's vision for the NII. Indeed, although
certain segments of the NII are overlapping and interdependent,
others are evolving with apparently little interaction. One of the
goals of this study is to identify where inconsistencies exist
between the evolutionary directions of the NII segments and to
identify the degree to which the combined segments miss the vision
put forward for the future NII. Based on the results of this study,
specific recommendations will be developed for reshaping
evolutionary directions toward the target vision.
To understand how these segments are likely to evolve, industry
experts from the relevant segments of the NII were invited to a
series of NII evolution workshop meetings of the XIWT. These
industry experts were asked to address three questions: (1) How
would you characterize today's NII with regard to this industry
segment? (2) What changes do you forecast for this industry segment
over the next 3 years? and (3) What changes do you forecast will
occur over the next 6 years?
The 3- and 6-year time horizons were found to be convenient
milestones. Most industry planners have well-articulated views of
how their industry will change during the next 3 years based on
existing exploratory efforts and announced business plans. Changes
likely to occur in 6 years are harder to predict; still, this is
within the planning horizon of most companies.
These industry experts were asked to present their most likely
scenarios—the one they would bet on occurring, not a fanciful
view of what could be possible given dedicated industry and
government efforts. These forecasts are predicated on whatever
regulatory and policy changes these industry experts believe will
probably occur during this planning period.
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Residential Broadband Evolution
Many services envisioned for the NII will demand significant
amounts of communications bandwidth. To extend these services to
the general public, broadband access networks to private residences
and apartments will play a critical role in the NII. Residential
broadband (RBB) networks are already widely deployed for
entertainment video distribution services. Future residential
broadband networks will provide increased bandwidth and two-way
interactive capabilities supporting a wide variety of
applications.
To characterize today's RBB networks and to understand how they
are evolving to provide the capabilities needed in the future NII,
the XIWT invited industry experts representing CATV companies,
local exchange carriers, RBB equipment manufacturers, and satellite
communications service providers to discuss current and future RBB
networks.
The following is a summary of the views of these industry
experts. It does not necessarily represent the views or positions
of the XIWT or its member companies.
Residential Broadband Today
Access Architecture
Today's residential broadband (RBB) is composed of over-the-air
broadcast networks, CATV networks, microwave access networks, and
direct reception from home satellite antennas. With the exception
of emerging satellite-based delivery systems, today's RBB access
networks are based on 6-Mhz analog channels. In a recent study of
CATV networks conducted by CableLabs, typical downstream capacities
were as follows:
•
22 percent have less than 30 channels;
•
64 percent have 30 to 53 channels; and
•
14 percent have 54 channels.
Although the amplifier housings employed in current CATV
networks are designed to accommodate a return path amplifier (i.e.,
they are two-way ready), most of today's CATV systems have
unactivated return channels. Roughly 20 percent of today's CATV
systems use some fiber-optic links to bypass long amplifier chains
in the trunk portion of the network. Currently a mix of 300-, 400-,
450-, and 550-MHz amplifiers is used. Service is typically provided
to residences and apartments, with relatively few business
locations connected to CATV networks. There is usually only a
single CATV operator in a given service area, with nascent
competition from microwave and direct broadcast satellite service
providers. TVRO (television receive only) background antennas that
are 1 to 2 meters in diameter are used by a small fraction of
residential customers.
Services available over today's RBB networks typically consist
of the following core set:
•
Basic video;
•
Subscription pay;
•
Pay-per-view;
•
Special events; and
•
Shopping channels.
In addition, the following emerging services have been deployed
on a limited basis:
•
Near video on demand;
•
Electronic video guides;
•
Low-speed and high-speed data access;
•
Digital video services via high-power satellites;
and
•
High-speed, downlink-only data via high-power
satellites.
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Residential Broadband: 3-Year View of
Access Architecture
Three years from now most CATV networks are expected to be
750-MHz systems providing 77 analog channels in the 54- to 550-MHz
band and hundreds of digital channels in the 550- to 750-MHz band.
Most CATV networks in that time frame will have fully activated
return paths using the 5- to 40-MHz band. These systems will have a
maximum chain of four to five amplifiers providing improved quality
and reliability. There will be a clustering of cable systems in
many metropolitan areas to provide connectivity to business and
residential customers throughout these metropolitan areas.
Local exchange carriers will provide video dial tone (VDT)
service in many metropolitan areas using either hybrid fiber-coax
access or fiber-to-the-curb architectures. These VDT networks will
include a level-1 gateway for selecting the video information
programmer. The video information programmer will provide a level-2
gateway for selection of the specific video channel. Most VDT
networks will include three to five level-2 providers, including
the LEC itself.
High-power direct broadcast satellites allowing reception from
small antennas (those less than two feet in diameter) will be
widely available for supporting video and data services to
residences. Terrestrial radio frequency access networks using
cellular principles in the 30- to 40-GHz band will be deployed in a
number of areas.
By 1998, many of today's emerging RBB services will be
considered core services of most RBB networks. The following core
RBB services are expected to be available:
•
Basic video;
•
Subscription pay;
•
Pay-per-view;
•
Special events;
•
Shopping channels;
•
Near video on demand;
•
Electronic video guides;
•
Low-speed and high-speed data access;
•
Digital video services via high-power satellites;
and
•
High-speed, downlink-only data via high-power
satellites.
In addition, the following emerging services are expected to be
deployed on a limited basis in 1998:
•
Telephony for second and third lines;
•
Video telephony;
•
Entrepreneurs providing niche information services
(e.g., travel services);
•
Interactive games;
•
Greater variety of shopping services; and
•
More education applications.
Residential Broadband: 6-Year View of
Architecture
From 1998 to 2001, fiber will migrate closer to residences,
allowing available bandwidth to be shared among fewer customers and
providing increased upstream bandwidth.
Despite current experimental deployments of 1-GHz cable systems,
CATV networks in 2001 are expected to be predominantly composed of
750-MHz fiber serving area systems. Fiber node sizes will be
reduced to 125 to 250 homes, with a maximum of 1 or 2 amplifier
cascades with a move toward entirely passive networks. To provide
additional upstream capacity, the analog portion of the spectrum
could be reduced to 88 to 400 MHz and
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the return path expanded to 5 to 70 MHz. Satellites with onboard
ATM switching will be deployed supporting two-way bandwidth on
demand.
By 2001, the following are expected to be core services of RBB
networks:
•
Basic video;
•
Subscription pay;
•
Pay-per-view;
•
Special events;
•
Shopping channels;
•
Community bulletin boards;
•
Electronic program guides;
•
Near video on demand;
•
High- and low-speed data services;
•
Video shopping malls;
•
Competitive access systems;
•
Video conferencing;
•
Overwhelming merchandising including electronic
coupons;
•
Telemedicine to the home; and
•
Do-it-yourself guides (e.g., auto repair).
Summary
This paper presents the methodology being used by the XIWT in
its NII evolution study and summarizes information collected on RBB
evolution. The XIWT continues to collect information on industry
evolution plans in other NII segments. This information will be
included in a forthcoming white paper on NII evolution.
Representative terms from entire chapter:
catv networks
