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There
is now a whole new way to connect to the Internet and
to network computers in a LAN, by using the world's
largest existing network-the power grid. by oo Gin
Lee
PLC
uses the existing electrical wirings hidden in the walls
of homes and buildings, users can do away with messy
cables and do not need to open floorboards, hack walls
and break ceilings to run the wires Powerline
communications (PLC) may soon be a viable alternative
to DSL and cable for last mile connectivity, and as
power grids already cover 95 percent of the world, it
also offers better penetration. PLC makes use of existing
low-voltage electrical cables to transmit data and voice
signals, and allows services such as LAN, broadband
Internet access, telephony, and fax.
For utility suppliers, PLC opens a whole new revenue
stream for them which they can deploy quickly. For service
providers buying wholesale services from utility companies,
PLC also offer various benefits, including the speed
and cost of deployment and the ability to break the
telco monopoly on last-mile access in many countries.
| How
it works |
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The
technology behind PLC is not exactly new. For
decades, sending data over the very same cables
that carry electricity has been used in limited
applications like controlling street-lamps
Initial efforts by Siemens AG and Nortel Networks
to offer Internet access through the electrical
outlets ended up in abject failure. Frustrated
by technical problems, the two companies threw
in the towel in 1999 and 2001 respectively, claiming
that powerline Net access did not have the potential.
But technological advancements over the last few
years have overcome the technical issues, most
notably that of line noise or interference from
electrical devices plugged into the same electricity
grid, which can disrupt data-transmission.
PLC works by transmitting data signals through
the same power cables that transmit electricity,
but it uses a different frequency. To do this,
every PC needs to be attached with a PLC adaptor,
which also functions as a modem.
To PLC-enable its power grid, the utility company
has to install an outdoor master device at the
power substation. The Internet backbone using
fibre or other traditional technologies is then
connected to this outdoor master.
The outdoor master acts as an administrator for
the outdoor systems and as a gateway to connect
the PLC system with the backbone network. The
outdoor master is in turn connected to one or
more access points. The access points connect
the indoor to the outdoor systems. Externally,
it acts as a slave device to the outdoor master
but internally it administers the PCs connected
using the PLC adaptor.
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Powerline
around the world
There are currently two main technology providers Switzerland's
Ascom and Israel's Main.net PLC. Between them, they
have helped to start PLC services in many countries
including Germany, Sweden, Singapore and even the remote
ski-resort cities in the Austrian Tyrolean mountains.
In Singapore, the incumbent utility company Singapore
Power (SP) started technical trials last November, using
a test-site at the Singapore Polytechnic. Initial speeds
of 800 Kbps and later 2.25 Mbps were achieved.
Then in April this year, SP announced it was working
with two local service providers Pacific Internet and
Little Green Apples (LGA) to roll-out commercial trials
of the Internet access via power-socket technology which
could now reach 45 Mbps. The "test-sites"
involved about 500 users from a school, commercial buildings
and homes. Commercial services are expected to be launched
late 2002 or early 2003.
Technology pros and cons
Current PLC technology has reached a maximum speed of
45 Mbps. This is divided into a maximum 27 Mbps for
downstream speeds and 18 Mbps for upstream speeds. In
Singapore, PLC will have the highest access speeds,
compared to ADSL clocking in at 512 Kbps and cable at
1.5 Mbps.
However, as PLC is a point-to-multipoint technology,
the 45 Mbps needs to be shared by users in a building
or within an area. Basically, 45 Mbps is the bandwidth
for one substation. PLC's significantly higher upload
and download speeds make it suitable for a variety of
two-way applications like peer-to-peer networking, file-sharing
over the Internet, and interactive distributed online
services like games and Web-cams.
Because PLC uses the existing electrical wirings hidden
in the walls of homes and buildings, users can do away
with messy cables and do not need to open floorboards,
hack walls and break ceilings to run the wires. PLC
also enables indoor networking for PCs and printers,
plus shared Internet access between PCs in an office
or home.
In addition, PLC boasts a superior distance of 300m
(without using repeaters) compared to 100m for standard
Fast-Ethernet and about 50m for 802.11b wireless connections.
However, there are potential security issues because
a single power line from the utility company goes to
multiple homes and office buildings. This means that
hackers can "listen in" on the shared bandwidth.
But according to RWE Powerline, a service provider that
has rolled out commercial PLC services in Germany, security
is not an issue. Its website says that PLC is harder
to tap than GSM mobile phones.
Viability to utility company
For utility companies, PLC opens up a new revenue stream
at minimal or moderate risk.
Explaining SP's decision to use PLC technology, its
President Rear-Admiral (Ret) Kwek Siew Jin, said: "PLC
involves expanding the use of existing energy infrastructure
for transferring information. Since SP is already transporting
electricity through its networks, it is thus synergistic
to leverage on SP's core assets and spur the use of
this technology."
For utility companies, there are three business models:
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The wholesale model where the utility company provides
the last-mile infrastructure to ISPs, like what SP
is doing
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The data only model where the utility company acts
as the ISP for data services
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The full ISP model where the utility company acts
as ISP for voice and data services
According to a white paper by Ascom, the wholesale model
offers a very safe investment with an expected ROI of
between 5-10 percent. The second model offers an attractive
investment at a moderate risk, with ROI ranging between
10-15 percent. And the full ISP model offers a very
attractive investment with moderate risk, with the ROI
at 15-20 percent.
In Singapore, SP is using the wholesale model, providing
the back-end last-mile infrastructure access while ISPs
Pacific Internet and LGA interface with end-users.
Viability to service providers
For Pacific Internet, SP's entry into the Internet access
business means that it can be less reliant on rivals
SingTel and StarHub, both of which own their own last-mile
infrastructure by way of telephone lines for the former
and telephone lines and cable for the latter.
Sui Wee Chong, Senior VP, consumer and corporate (sales
& marketing), Pacific Internet Singapore, said that
this will allow the company to be a broadband provider
of choice to customers, and to recommend the best solution
that suits their needs.
Yew Hock Meng, Chief Marketing Officer of LGA, said
that PLC lets his company deploy Internet access solutions
faster and cheaper to LGA's customers.
"In
the past, you needed technicians to do wiring and connections.
Now we can just deliver pre-configured PLC modems and
users can just plug-and-play," said Yew.
He added that cost-savings come from taking away the
need for pulling messy Ethernet wires, plus saving the
cost of patching telephone lines every time a new household
or office apply for Internet access.
But he does not expect PLC to replace the other existing
technologies like DSL and Wi-Fi as they are complementary.
Powerline networking
PLC technologies can also be used to network computers
for file and printer sharing, or sharing cable or ADSL
Internet access among computers in a Powerline network
much like an Ethernet LAN.
All the users need is a sandwich-sized adaptor for every
PC that needs to be connected. One end of the adaptor
goes into the Ethernet or USB port of the PC while the
other plugs into the mains socket.
To share Internet access, a powerline bridge needs to
be connected to the router. One end of the bridge is
connected via Cat-5 cable into the uplink port of the
router, while the other end goes into the power socket.
Several vendors have released or are soon releasing
these powerline networking products, including LinkSys,
Gigafast, SMC and NetGear.
LinkSys will also be releasing a powerline router (which
has Ethernet ports) soon, which removes the need to
connect a second device (the powerline bridge) to the
router.
According to LinkSys, the cost of the powerline adaptors
(Ethernet or USB) is about US$180 while the upcoming
router will be about US$200.
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