Powerline Networking

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Powerline
Networking

by Michael Gariffo

Docid: 00021034

Publication Date: 2208

Report Type: TUTORIAL

Preview

Powerline networking is a technology capable of transmitting data over
the electrical wiring already present in nearly all homes, businesses,
multi-unit dwellings, and even whole cities. Not only does this type of
network remove the need for additional on-site Ethernet or wireless
connections when forming a network, it also makes it possible for existing
electrical grids to serve as a wide area network with very little
alteration. Despite having been in existence for nearly a century,
it is only within the past few decades that the technology’s
potential has been realized and only within the last few years that its
usage has become widespread. This report will examine the history of powerline networking, how it works, and the potential it offers to home
and business networks as well as smart grid installations.

Executive Summary

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Powerline
networking is a technology that allows for the existing electrical wiring
in a home, business, or even whole town to be used as networking hardware.
It makes this possible by replacing the Ethernet cabling or Wi-Fi signal
with a signal that is transmitted over the powerline itself. This
transmission is handled by a specialized piece of hardware that can translate data into an electrical signal that is
then sent
across the powerline without disrupting the normal flow of
alternating current (AC) being sent across that same line. The translated
signal is received by another specialized unit on the opposite end of
the powerline where it is converted back into its original form of data.
The entire process if very similar to the practice of breaking data into packets
that are sent across any modern IT network. The main difference is that the data
is traveling across a live electrical line.

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Wireless
Local Area Network Technology Tutorial

Wi-Fi Standards and Amendments Technology Tutorial

Smart
Grid Technology Tutorial

Because powerline networks are formed by using existing electrical grids, their
benefits are numerous and quite unique among modern networking
technologies. These include being able to operate in areas where Wi-Fi is
subject to too much interference, being viable to install in locations
where running Ethernet cabling is not an option, and offering the ability
to network far-flung homes, businesses, and power stations for smart grid
installations. With the ongoing rise of the Internet of Things (IoT), powerline networking could become a very important,
very helpful method of connecting millions of disparate devices,
especially given the fact that nearly all of these devices will already
be plugged into some form of electrical connection.

History and Description

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History

The possibility of transmitting data across power lines actually
existed long before the first computers came into being. Prior to computer
networks being a focus, powerlines were considered for the transmission of
telecommunications data. This can be tracked as far back as 1922 with
carrier frequency networks operating over high-tension wires, a practice
that remains in limited use today.¹ Despite the potential
offered by this technology, its technical limitations and the lack of
development of a technology to take advantage of the networking possibilities led
to several decades of it wallowing in relative obscurity.

It was not until the 1970s that powerline networking would once again
become a topic worth exploring. Perhaps unsurprisingly, it was the energy
companies themselves who began using it to automate
the often arduous process of reading electric meters. Rather than
sending personnel to each customer’s home, the technology
offered a possibility of installing specialized meters that could
transmit simple usage data over the electrical grid back to the
power company without the need for any human interaction aside from
collecting the data at a central location.² The technology was
adopted by power companies across the globe and remains in use by some
utilities to this day.

While the aforementioned uses were certainly promising and potentially
groundbreaking, they only scratched the surface of what became
possible once powerline networking was applied to PC networks during the 1980s. For the first time, the technology was
considered as a way to transmit more complex forms of data,
eventually including information derived from the then-nascent Internet.
While powerline networking was surpassed in speed and reliability by other
local area network (LAN) technologies such as Ethernet and eventually Wi-Fi, it remained a niche
solution for very specialized situations.
Its relative obscurity was largely due to comparatively slow speeds, risk of interference, and additional complications. However, this all changed when
improvements in digital signal processing made it possible for units
barely larger than the average laptop power brick to serve as powerline
networking endpoints. Suddenly, powerline networks were a consideration
for not just utility companies but also for the average consumer or
business user. This is where powerline networks find themselves today,
poised to meet or exceed the speeds offered by more well-known local
networking technologies while also offering advantages for smart grid and IoT installations that Ethernet and Wi-Fi
struggle to match.

Description

As stated above, powerline networks make use of existing electrical
grids – whether they are in a home, business, or an entire city – as the
transmission medium for digital data. The advantages of this are obvious
and numerous as essentially everything capable of producing or receiving
digital data is already connected to a power grid at some point. This sort
of in-place I/O port means that nearly any desktop or mobile computing
device has the potential to become a powerline networking device
if the correct hardware is included. For the vast majority of
current powerline networking installations, however, the actual transmission of
data is handled by a specialized unit that translates the data in
question from its original form into a signal that can be
transmitted across an electrical line without disrupting or interfering
with the flow of alternating current already crossing that line.

The most common scenario includes a pair of
adapters that are connected to two power outlets within a home or
business. Each adapter would be connected to
the device of the user’s choice via networking hardware – typically an Ethernet cable
– and would then be plugged into a wall outlet where it would
establish a connection with its counterpart that is also plugged into an
outlet on the opposite end of the electrical circuit. Each
termination point of this binary network would include a PC, modem,
router, streaming media device, or some other form of electronic device
capable of sending and/or receiving digital data. When the data is
introduced to the network by the first device, it is transmitted over the
networking cable into the adapter. At this point, it is
converted into an electrical signal, typically somewhere in the 3kHz
range, which is sent over the electrical line to the other adapter.³
Because most in-building electrical power operates at a frequency of 50 to
60 Hz, the frequency between powerline networking signals and the much
lower frequency power distribution allows for the data to pass over the
same conduit as the power without either signal interfering with the
other.⁴Once the translated electrical signal reaches its
endpoint, it is received by the second adapter where it is translated
back into its original form and subsequently sent to whatever device is
connected to that end. The result is a process that, as far as the
connected devices can tell, is indiscernible from transmitting their data
over a run-of-the-mill Ethernet network.

While there are several other considerations and obstacles introduced
by the usage of electrical lines as a transmission medium, these have
largely been dealt with in most modern installations and are no more
discouraging than similar limitations from competing technologies, such as Wi-Fi interference or range issues.

This example of powerline networking relates primarily to
in-home and in-business uses. As previously mentioned, utility
companies have for several decades been able to use the technology to
network devices over city-wide power grids. While these installations
are equally important, when compared to on-site uses they are nearly
impossible to define with a single summary due to the wide
variety of disparate hardware, grid types, and use cases. Unlike the average user purchasing an
off-the-shelf powerline networking adapter, utility companies have the
ability to build their powerline networks from the ground up, designing
their own hardware, termination points, and smart-grid technology. This
provides massive potential for future installations, but also makes it
relatively useless to provide a single example scenario.

Figure 1. A TP-Link AV500 Nano Powerline Adapter Kit

Source: TP-Link

Current View

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This section will be divided into two categories: On-site powerline networking, which will address the use of this technology within a single
home, office, or building; and smart grid powerline networking, which will
address the use of the technology on the scale of a larger
power grid. Each section will describe the current capabilities and
limitations of powerline networking technology within the applications
specific to its purview.

On-Site Powerline Networking

Benefits and Performance

For the home user, business user, or even enterprise-class user,
powerline networking offers several advantages over Ethernet or Wi-Fi.
Compared to Ethernet, a home or business is much more likely to have
powerline infrastructure already in place than it is to have Ethernet or
the ability for Ethernet to be easily run. While this may not pose too
much of an issue for enterprise users that are able to route cables
through the usual conduits found in most modern offices, it does pose a
considerable issue for those working in a home or small business office
where they may be unable to access interior wall spaces due to design or the rules of
a rental agreement. In this case, powerline networking can be a
lifesaver by offering a wired connection via the outlets already present
in that home or office.

Similarly, certain homes or offices are challenging environments for
Wi-Fi installations, either because of interference from multiple
connected devices or due to structural issues such as steel reinforced
walls that can block a wireless signal. In these cases, powerline
networking can also prove to be a savior as it is not nearly as prone to
interference from other electronic devices.

While all of these benefits are tempting, none of the advantages are
worth much if the speed and reliability are not capable of matching or exceeding those offered by Wi-Fi or Ethernet. Thankfully powerline networks have improved to the
point where they can indeed match the speeds of even the best Ethernet
connections, while surpassing most in-home and small business Wi-Fi in use
today. This is thanks to the availability of gigabit-capable units from
companies like TP-Link, Netgear, Trendnet, Linksys, and others. These adapters can
transmit data in an ideal environment as fast as 2,000 megabits per
second – twice the speed a modern gigabit LAN network is expected to
provide. Furthermore, they are able to do this while offering essentially
the same reliability as any Ethernet connection due to the fact that powerline networking adapters, for all intents and purposes, turn a given
stretch of a home’s electrical wiring into a sort of Ethernet extension
cable with a connection just as stable as it would be over a couple
hundred feet of Category 5 or 6 cabling.

Finally, powerline networks can also offer a very exciting potential for a budding area of technology: home automation. This
"smart home" would otherwise largely rely on
Ethernet and Wi-Fi connections. However, with the introduction of an
in-home powerline network, the connectivity needed for products such as
lighting, connected appliances, thermostats, and more could be handled by
the very same connection providing their power. While the
technology has not seen widespread adoption for this purpose just
yet, it is ready and waiting to fulfill the connectivity needs of
tomorrow’s connected and automated home.

Drawbacks and Weaknesses

Like any communications or networking technology, powerline networks
are not without their drawbacks. While they tend to be very stable and
useful once they are installed, they are not ideal for all
environments and can be degraded or rendered useless if the wrong power
infrastructure is in place or if a home has the wrong type of wiring. It
would be difficult to cover all the factors that
can affect a powerline network, but it is possible to explain the two main
causes of installation or performance failure, one of which is easily
corrected.

The primary issue that can degrade the signal of a powerline network is
aging or faulty wiring within a home or business. While this is an obvious
concern for other safety reasons, even a modest wiring issue that poses
no other risk could potentially result in degrading the speed or
performance of a powerline network. These minor factors include wires
without adequate shielding, the adjacent placement of strong sources of
radio signals, the presence of electro-magnetically active areas near
either termination point or within the powerline itself, wire breaks, and
other issues. While all of these can affect a network, they are relatively
rare within most modem and well maintained homes and businesses, posing
little risk to most installations.

The more likely culprit for failed installations – and the easiest to
fix – is actually a safety measure itself: surge protectors. These
devices are specifically designed to "clean" the electrical
signal being provided to the appliances plugged into them. This goal can
result in the data signal created by the networking adapter being picked up as
"noise" in the electrical signal, resulting in it being
filtered out by the surge protector and never reaching its destination.
For this reason, most powerline networking adapter manufacturers strongly
recommend that the adapter be plugged directly into a wall outlet. Any other needed power
can be provided via the pass-through power outlet
included on most adapters, which can be seen in the figure above.⁵

A final concern does not cause any detriment to the operation of the
powerline network itself, but can have a negative impact on other electronic
devices. In this scenario, interference from the powerline networking signal can
cause "noise" to be picked up by other electronic devices. This includes both
literal noise, in the case of audio output devices connected to the same
electrical circuit, as well as the visual variety in the case of displays and
televisions. Similarly, in situations where other, wireless forms of networking
are also in use (WiFi, Bluetooth, 2.4GHz wireless peripherals, etc) the
electrical signal fluctuations passing through in-wall power lines can result in
interference. Although this will not necessarily appear in all installations, the
proximity of these types of devices with networking hardware in most homes and
offices does make it a major concern.

While powerline networks may be impractical in the oldest homes or
buildings, because of the resilience of most modern units there is generally very little risk of a complete malfunction
and only a moderate risk of signal or speed degradation from
infrastructure issues.

Smart Grid Powerline Networking

As stated at the start of this report, a form of powerline networking
has been in use by utility companies for decades to read meters. This is
an example of a one-way communication system in which the data being
provided by the meter’s sensors is automatically sent along the power
lines back to a central station where it is collected and recorded for
billing and reporting purposes. While this is extremely useful and much more
efficient than sending out personnel to physically read each customer’s
meter, it is by no means the extent of the possibilities available from powerline networking and is not even considered to be a
true
"smart grid" technology.

For real smart grid interactivity over powerline networks, a two-way
system is required. In this scenario, both ends of the network are capable
of both sending and receiving data. This expands the possibilities from
simple meter reading to a catalog of uses that covers nearly every major
concern possible when operating a utility company. With such a system in
place, power companies can monitor usage on a level so granular that
predicting consumption spikes and drop-offs would be easier than ever.
This could prevent power outages, reduce wasted power consumption, and
even reduce the cost of electricity for the customer thanks to its
ability to boost efficiency. This level of scalability can be applied to
other areas of power provisioning as well, including load control, sensor
management, fault responses, and more.

As with on-site powerline networking, this application of the
technology is not without its shortcomings. The biggest issue here is a limitation
in the speeds available to grid-wide installations due to the vast
physical distances that must be traversed by the data being transmitted.
Where an in-home network might only need to sustain a signal over a couple
hundred feet of conduit, a smart-grid signal must be sustained over
several miles before reaching its termination point. Thankfully there is
help in this goal, coming in the form of repeater stations. These
facilities work like a Wi-Fi extender: taking in a signal, cleaning it,
amplifying it, and sending it on to its final destination. While these
network components can extend the range of a signal many times over, the
ultimate speed possible in a smart-grid network is still a minor fraction
of what in-home networks can achieve, often topping out at just under 600
kilobits per second.⁶Although these limited speeds may seem
restrictive to the point of absurdity, it must be remembered that the data
being transmitted over these networks is relatively simple in nature. From
meter readings to on/off and adjustment commands, most transmissions over
smart grids can be summed up in just a few lines of code. For this reason,
the data rate needed to operate a smart grid installation is actually very
modest and entirely within the range offered by the aforementioned
speeds.

At this point, it is worth wondering if the promise of such
technologies is simply a pipe dream or a form of electrical vaporware
that will never materialize. Thankfully,
that does not appear to be the case as several major initiatives have
already begun efforts to apply powerline networking technology to
real-world electrical grids. The most recent and high-profile of these
alliances is known as G3-PLC, a group composed of network operators such
as ERDF and Enexis, power meter vendors, and well-known chip makers
including Texas Instruments and STMicroelectronics.⁷ The group,
which is heavily focused on Asia, promotes the adoption of its eponymous
standard, which comprises a powerline networking technology developed and
designed to be resilient and adaptable to the needs of modern power
suppliers. The technological group’s standards have already been
recognized by the International Telecom Union as standard G.9903, making
them one of the first powerline networking developers to receive global
accreditation from such a well-known industry group.⁸

Outlook

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Despite its age as a concept, powerline networking is a technology that
is only just now coming into its own. Like any networking protocol, it has
taken time to reach even moderately widespread adoption, and it
will take even more time to reach the kind of ubiquity that will
cause manufacturers to build the technology into their products.
If and when this occurs, the benefits to home automation, the Internet of
Things, and home networking in general could be massive. Imagine a situation
in which most Wi-Fi was unnecessary because every outlet in a home also
served as a direct conduit to its broadband connection or a scenario in
which smart appliances could draw and transmit all the data they could
ever needed simply by being plugged into a standard outlet.

Similarly, smart grids are poised to solve many of the power
consumption and distribution problems that face the world today. From
improving efficiency at every level to reducing waste and providing
infinitely better data on demand, these intelligent grids could
revolutionize electrical utilities. However, in order to accomplish their
goals, these grids must have a network to operate on. Powerline networking
provides this platform via the very power lines that the electrical
infrastructure itself is already made of. No simpler or more easy-to-integrate solution could be conceived.

With all that said, it is still necessary to temper one’s enthusiasm.
Like any technology, powerline networking relies on the adoption of
manufacturers, consumers, and regulators to become a widespread part of
the modern landscape. While it offers a multitude of benefits, its
drawback have made many wary of its promise. Signs are currently pointing
to the drawbacks being eliminated and the benefits expanding.
Still, many promising technologies have gone by the wayside because a
better supported alternative was available. Take, for example, Wi-Max, a
wireless communications protocol that was being promoted by several major telecom providers.
Despite this, it was soundly and finally beaten by the
alternative technology LTE, which powered nearly every modern cellular network in
the world, at least until it is ultimately displaced by the expanded use
of 5G standards. Even the most promising technologies can fail. Nonetheless, it would be in the best interest of the Internet of Things,
electrical utility companies, IT departments, and even the average home
user if powerline networking were heartily supported and expanded. After
all, the need for electricity shows no signs of ending any time soon, and
it would be incredibly useful if that power supply could also serve as one
of the single greatest networking assets the world has ever seen.

References

¹
Dostert, Klaus M. "Telecommunications Over the Power Distribution
Grid – Possibilities and Limitations." International
Symposium on Power Line Communications and Its Applications. Retrieved
June 2017.
² Hosono, M. "Improved Automatic Meter Reading and
Load Control System and Its Operations Achievement." International
Conference on Metering Apparatus and Tariffs for Electrical Supply.
October 1982.
³ "Powerline Communications (PLC – Telecom ABC)" TelecomABC.com.
Retrieved June 2017.
⁴ Ibid.
⁵"Can a Powerline Adapter Be Plugged into a Power Strip or
Surge Protector?" Sony. Retrieved June
2017.
⁶"Draft Specification for PowerLine Intelligent
Metering Evolution." PRIME
Alliance. 2011.
⁷"Alliance Members." G3-PLC Alliance.
Retrieved June 2017.
⁸"G.9903 ITU-T." International Telecommunication Union
– ITU Telecommunication Standardization Sector.
March 2013.

Web Links

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About the Author

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Michael Gariffo is an editor for Faulkner Information Services. He
tracks and writes about enterprise software, the Web, and the IT services
sector, as well as telecommunications and data networking.

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