By far, the most widely used
broadband technology to access
the Internet around the world
today is DSL. Over 70% of broadband connections in Japan and
Korea are DSL, while penetration in Europe is approximately 60%.
In the U.S., cable TV companies dominate broadband. But DSL isn't far behind,
with about 46% of total connections. In
fact, DSL growth is estimated at 15% to
20% annually, so it's expected to pass
cable TV sometime this year as the dominant broadband technology in the U.S.
That says a lot, considering DSL uses
the century-old #26 AWG twisted pair of
the plain-old telephone system (POTS).
Nevertheless, DSL is alive and well. In fact,
it's expected not only to continue its
growth in the U.S., but to become even better to meet the telcos' triple-play plans.
While growth figures for DSL are attractive, they don't tell the whole story. The
Government Accountability Office report
last year indicated that only 58% of U.S. households had any sort of Internet
access, with 30% using dialup and 28%
using broadband (cable, DSL, satellite).
Another study from the Pew Internet &
American Life Project showed that 42% of
U.S. citizens have access to a broadband
connection, the majority of whom reside in
cities and the suburbs.
Rural areas are really underserved, with
only an estimated 25% having any kind of
high-speed Internet connection. (Yet AT&T
and Verizon—the two largest DSL
providers—claim to offer DSL service to
80% of their subscribers). This shortage
won't be easily resolved, as the telcos and
cable TV companies usually don't think it's profitable to provision so few customers in
such remote areas.
Together, these factors leave a huge
opening for some reasonably priced satellite technology or other wireless option.
Satellite broadband connections are
already available in some areas where
satellite TV service is available. But the
opportunity is a reality for DSL providers
because the wiring is there. All they need
to do is enable the service.
Flavors Of DSL
All DSL systems are
based on orthogonal frequency-division
multiplexing (OFDM), which divides the
high-speed bit stream into many slower
parallel streams and modulates each on
adjacent carriers. The telcos refer to
OFDM (also known as multicarrier modulation) as discrete multitone or DMT. Several
versions are being implemented, and
ADSL is the most widely used by far.
A Fresh Example
Texas Instruments'
UR8 residential gateway architecture chip
set exemplifies the latest trends and features based on DSL ().
Designed for home gateway boxes, the
chips cover all the latest DSL offerings,
including the newest VDSL2 standard.
Also, these chips feature a multimedia
gateway processor, a programmable DSL
physical layer (PHY), a high-performance
DSP-based voice subsystem, and a rich
set of local-area network (LAN) interfaces.
A well-defined application program interface (API) reduces time-to-market by allowing hardware and software reuse across
all DSL platforms.
This chip set lets residential gateway
designers handle Voice over Internet Protocol (VoIP), as well as multiple methods
for distributing broadband services within the home. Some of the home networking technologies supported
include Ethernet, Wi-Fi, and standards offered by the HomePlug
Powerline Alliance, Multimedia over Coax Alliance (MoCA), and
the Home Phoneline Networking Alliance (HomePNA).
No one knows which home networking technology will dominate in the future. Most homes with a network rely on Wi-Fi
because of the conveniences of wireless. But will existing or even
future wireless technologies have the bandwidth to support the
triple play of high-speed data, VoIP, and Internet Protocol TV (IPTV)
and video on demand (VOD)? That remains to be seen.
While IEEE 802.11g Wi-Fi systems seem to have the potential,
current access points have limitations because walls, ceilings,
and other obstructions shorten range and create dead zones.
High attenuation and multipath cause speed to back off dramatically for a reliable connection, making video transport more iffy.
That's why so many vendors are joining with the MoCA and
HomePNA crowd to support wired technologies that will virtually
guarantee quality video transmission. Some new wireless systems
such as the 802.11n upgrade and TZero's version of Ultra-Wideband (UWB) using multiple-input multiple-output (MIMO) may do
the job. In any case, expect multiple home networking methods in
the mix. Whatever works the best for the least money will win.