<s>
Power-line	B-Device
communication	I-Device
(	O
also	O
known	O
as	O
power-line	O
carrier	O
or	O
PLC	O
)	O
carries	O
data	O
on	O
a	O
conductor	O
that	O
is	O
also	O
used	O
simultaneously	O
for	O
AC	O
electric	O
power	O
transmission	O
or	O
electric	O
power	O
distribution	O
to	O
consumers	O
.	O
</s>
<s>
A	O
wide	O
range	O
of	O
power-line	B-Device
communication	I-Device
technologies	O
are	O
needed	O
for	O
different	O
applications	O
,	O
ranging	O
from	O
home	O
automation	O
to	O
Internet	O
access	O
which	O
is	O
often	O
called	O
broadband	B-General_Concept
over	O
power	O
lines	O
(	O
BPL	O
)	O
.	O
</s>
<s>
A	O
number	O
of	O
difficult	O
technical	O
problems	O
are	O
common	O
between	O
wireless	O
and	O
power-line	B-Device
communication	I-Device
,	O
notably	O
those	O
of	O
spread	B-Architecture
spectrum	I-Architecture
radio	O
signals	O
operating	O
in	O
a	O
crowded	O
environment	O
.	O
</s>
<s>
Power-line	B-Device
communications	I-Device
systems	O
operate	O
by	O
adding	O
a	O
modulated	B-Application
carrier	O
signal	O
to	O
the	O
wiring	O
system	O
.	O
</s>
<s>
Different	O
types	O
of	O
power-line	B-Device
communications	I-Device
use	O
different	O
frequency	O
bands	O
.	O
</s>
<s>
The	O
propagation	O
problem	O
is	O
a	O
limiting	O
factor	O
for	O
each	O
type	O
of	O
power-line	B-Device
communications	I-Device
.	O
</s>
<s>
The	O
main	O
issue	O
determining	O
the	O
frequencies	O
of	O
power-line	B-Device
communication	I-Device
is	O
laws	O
to	O
limit	O
interference	O
with	O
radio	O
services	O
.	O
</s>
<s>
Data	O
rates	O
and	O
distance	O
limits	O
vary	O
widely	O
over	O
many	O
power-line	B-Device
communication	I-Device
standards	O
.	O
</s>
<s>
Higher	O
data	O
rates	O
generally	O
imply	O
shorter	O
ranges	O
;	O
a	O
local	B-General_Concept
area	I-General_Concept
network	I-General_Concept
operating	O
at	O
millions	O
of	O
bits	O
per	O
second	O
may	O
only	O
cover	O
one	O
floor	O
of	O
an	O
office	O
building	O
,	O
but	O
eliminates	O
the	O
need	O
for	O
installation	O
of	O
dedicated	O
network	O
cabling	O
.	O
</s>
<s>
Thus	O
even	O
the	O
complicated	O
OFDM	B-Protocol
standards	O
can	O
still	O
be	O
economical	O
.	O
</s>
<s>
While	O
utility	O
companies	O
use	O
microwave	O
and	O
now	O
,	O
increasingly	O
,	O
fiber	B-Architecture
optic	I-Architecture
cables	O
for	O
their	O
primary	O
system	O
communication	O
needs	O
,	O
the	O
power-line	O
carrier	O
apparatus	O
may	O
still	O
be	O
useful	O
as	O
a	O
backup	O
channel	O
or	O
for	O
very	O
simple	O
low-cost	O
installations	O
that	O
do	O
not	O
warrant	O
installing	O
fiber	B-Architecture
optic	I-Architecture
lines	O
,	O
or	O
which	O
are	O
inaccessible	O
to	O
radio	O
or	O
other	O
communication	O
.	O
</s>
<s>
Power-line	B-Device
carrier	I-Device
communication	I-Device
(	O
PLCC	O
)	O
is	O
mainly	O
used	O
for	O
telecommunication	O
,	O
tele-protection	O
and	O
tele-monitoring	O
between	O
electrical	O
substations	O
through	O
power	O
lines	O
at	O
high	O
voltages	O
,	O
such	O
as	O
110	O
kV	O
,	O
220	O
kV	O
,	O
400	O
kV	O
.	O
</s>
<s>
The	O
modulation	B-Application
generally	O
used	O
in	O
these	O
system	O
is	O
amplitude	B-Device
modulation	I-Device
.	O
</s>
<s>
PLCC	O
can	O
be	O
used	O
for	O
interconnecting	O
private	B-Device
branch	I-Device
exchanges	I-Device
(	O
PBXs	O
)	O
.	O
</s>
<s>
A	O
PLC	B-Device
carrier	I-Device
repeating	I-Device
station	I-Device
is	O
a	O
facility	O
,	O
at	O
which	O
a	O
power-line	B-Device
communication	I-Device
(	O
PLC	O
)	O
signal	O
on	O
a	O
powerline	O
is	O
refreshed	O
.	O
</s>
<s>
the	O
signal	O
is	O
filtered	O
out	O
from	O
the	O
powerline	O
,	O
demodulated	B-Device
and	O
modulated	B-Application
on	O
a	O
new	O
carrier	O
frequency	O
,	O
and	O
then	O
reinjected	O
onto	O
the	O
powerline	O
again	O
.	O
</s>
<s>
PLC	O
also	O
may	O
be	O
a	O
component	O
of	O
a	O
smart	B-Architecture
grid	I-Architecture
.	O
</s>
<s>
Power-line	B-Device
communications	I-Device
technology	O
can	O
use	O
the	O
electrical	O
power	O
wiring	O
within	O
a	O
home	O
for	O
home	O
automation	O
:	O
for	O
example	O
,	O
remote	O
control	O
of	O
lighting	O
and	O
appliances	O
without	O
installation	O
of	O
additional	O
control	O
wiring	O
.	O
</s>
<s>
Typically	O
home-control	O
power-line	B-Device
communication	I-Device
devices	O
operate	O
by	O
modulating	O
in	O
a	O
carrier	O
wave	O
of	O
between	O
20	O
and	O
200	O
kHz	O
into	O
the	O
household	O
wiring	O
at	O
the	O
transmitter	O
.	O
</s>
<s>
The	O
carrier	O
is	O
modulated	B-Application
by	O
digital	O
signals	O
.	O
</s>
<s>
The	O
"	O
universal	O
powerline	O
bus	O
"	O
,	O
introduced	O
in	O
1999	O
,	O
uses	O
pulse-position	B-Device
modulation	I-Device
(	O
PPM	O
)	O
.	O
</s>
<s>
LonTalk	B-Protocol
,	O
part	O
of	O
the	O
LonWorks	O
home	O
automation	O
product	O
line	O
,	O
was	O
accepted	O
as	O
part	O
of	O
some	O
automation	O
standards	O
.	O
</s>
<s>
Narrowband	O
power-line	B-Device
communications	I-Device
began	O
soon	O
after	O
electrical	O
power	O
supply	O
became	O
widespread	O
.	O
</s>
<s>
French	O
electric	O
power	O
Électricité	O
de	O
France	O
(	O
EDF	O
)	O
prototyped	O
and	O
standardized	O
a	O
system	O
called	O
"	O
spread	B-General_Concept
frequency	I-General_Concept
shift	I-General_Concept
keying	I-General_Concept
"	O
or	O
S-FSK	B-General_Concept
.	O
</s>
<s>
(	O
See	O
IEC	B-General_Concept
61334	I-General_Concept
)	O
It	O
is	O
now	O
a	O
simple	O
,	O
low	O
cost	O
system	O
with	O
a	O
long	O
history	O
,	O
however	O
it	O
has	O
a	O
very	O
slow	O
transmission	O
rate	O
.	O
</s>
<s>
S-FSK	B-General_Concept
sends	O
a	O
burst	O
of	O
2	O
,	O
4	O
or	O
8	O
tones	O
centered	O
around	O
the	O
time	O
when	O
the	O
AC	O
line	O
passes	O
through	O
zero	O
voltage	O
.	O
</s>
<s>
Higher	O
levels	O
of	O
the	O
protocols	O
can	O
have	O
stations	O
(	O
usually	O
smart	B-Device
meters	I-Device
)	O
retransmit	O
messages	O
.	O
</s>
<s>
Since	O
the	O
mid-1980s	O
,	O
there	O
has	O
been	O
a	O
surge	O
of	O
interest	O
in	O
using	O
the	O
potential	O
of	O
digital	O
communications	O
techniques	O
and	O
digital	B-General_Concept
signal	I-General_Concept
processing	I-General_Concept
.	O
</s>
<s>
But	O
the	O
narrowband	O
powerline	B-Device
communications	I-Device
channel	O
presents	O
many	O
technical	O
challenges	O
,	O
a	O
mathematical	O
channel	O
model	O
and	O
a	O
survey	O
of	O
work	O
is	O
available	O
.	O
</s>
<s>
Applications	O
of	O
mains	B-Device
communications	I-Device
vary	O
enormously	O
,	O
as	O
would	O
be	O
expected	O
of	O
such	O
a	O
widely	O
available	O
medium	O
.	O
</s>
<s>
One	O
natural	O
application	O
of	O
narrow	O
band	O
power-line	B-Device
communication	I-Device
is	O
the	O
control	O
and	O
telemetry	O
of	O
electrical	O
equipment	O
such	O
as	O
meters	O
,	O
switches	O
,	O
heaters	O
and	O
domestic	O
appliances	O
.	O
</s>
<s>
Open	O
Smart	B-Architecture
Grid	I-Architecture
Protocol	O
(	O
OSGP	O
)	O
is	O
one	O
of	O
the	O
most	O
proven	O
narrowband	O
PLC	O
technologies	O
and	O
protocols	O
for	O
smart	B-Device
metering	I-Device
.	O
</s>
<s>
There	O
are	O
more	O
than	O
five	O
million	O
smart	B-Device
meters	I-Device
,	O
based	O
on	O
OSGP	O
and	O
using	O
BPSK	O
PLC	O
,	O
installed	O
and	O
operating	O
around	O
the	O
World	O
.	O
</s>
<s>
The	O
OSGP	O
Alliance	O
,	O
a	O
non-profit	O
association	O
originally	O
established	O
as	O
ESNA	O
in	O
2006	O
,	O
led	O
an	O
effort	O
to	O
establish	O
a	O
family	O
of	O
specifications	O
published	O
by	O
the	O
European	O
Telecommunications	O
Standards	O
Institute	O
(	O
ETSI	O
)	O
used	O
in	O
conjunction	O
with	O
the	O
ISO/IEC	O
14908	O
control	O
networking	O
standard	O
for	O
smart	B-Architecture
grid	I-Architecture
applications	O
.	O
</s>
<s>
OSGP	O
is	O
optimized	O
to	O
provide	O
reliable	O
and	O
efficient	O
delivery	O
of	O
command	O
and	O
control	O
information	O
for	O
smart	B-Device
meters	I-Device
,	O
direct	O
load	O
control	O
modules	O
,	O
solar	O
panels	O
,	O
gateways	O
,	O
and	O
other	O
smart	B-Architecture
grid	I-Architecture
devices	I-Architecture
.	O
</s>
<s>
OSGP	O
follows	O
a	O
modern	O
,	O
structured	O
approach	O
based	O
on	O
the	O
OSI	O
protocol	O
model	O
to	O
meet	O
the	O
evolving	O
challenges	O
of	O
the	O
smart	B-Architecture
grid	I-Architecture
.	O
</s>
<s>
This	O
uses	O
binary	B-General_Concept
phase	I-General_Concept
shift	I-General_Concept
keying	I-General_Concept
at	O
3592.98	O
BAUD	O
,	O
using	O
a	O
carrier	O
tone	O
of	O
86.232KHz	O
+	O
/	O
-	O
200ppm	O
.	O
</s>
<s>
This	O
standard	O
and	O
command	O
system	O
provides	O
not	O
only	O
for	O
smart	B-Device
meters	I-Device
and	O
related	O
data	O
but	O
also	O
for	O
general	O
purpose	O
extension	O
to	O
other	O
smart	B-Architecture
grid	I-Architecture
devices	I-Architecture
.	O
</s>
<s>
For	O
example	O
,	O
in	O
the	O
UK	O
and	O
Europe	O
a	O
TV	O
audience	O
monitoring	O
system	O
uses	O
powerline	B-Device
communications	I-Device
as	O
a	O
convenient	O
data	O
path	O
between	O
devices	O
that	O
monitor	O
TV	O
viewing	O
activity	O
in	O
different	O
rooms	O
in	O
a	O
home	O
and	O
a	O
data	O
concentrator	O
which	O
is	O
connected	O
to	O
a	O
telephone	O
modem	O
.	O
</s>
<s>
More	O
modern	O
systems	O
use	O
OFDM	B-Protocol
to	O
send	O
data	O
at	O
faster	O
bit	O
rates	O
without	O
causing	O
radio	O
frequency	O
interference	O
.	O
</s>
<s>
As	O
delivered	O
,	O
the	O
physical	O
layer	O
is	O
OFDM	B-Protocol
,	O
sampled	O
at	O
250kHz	O
,	O
with	O
512	O
differential	B-General_Concept
phase	I-General_Concept
shift	I-General_Concept
keying	I-General_Concept
channels	O
from	O
42	O
–	O
89kHz	O
.	O
</s>
<s>
It	O
uses	O
a	O
convolutional	B-Error_Name
code	I-Error_Name
for	O
error	O
detection	O
and	O
correction	O
.	O
</s>
<s>
The	O
upper	O
layer	O
is	O
usually	O
IPv4	B-Protocol
.	O
</s>
<s>
The	O
technology	O
used	O
is	O
OFDM	B-Protocol
sampled	O
at	O
400kHz	O
with	O
adaptative	O
modulation	B-Application
and	O
tone	O
mapping	O
.	O
</s>
<s>
Error	O
detection	O
and	O
correction	O
is	O
made	O
by	O
both	O
a	O
convolutional	B-Error_Name
code	I-Error_Name
and	O
Reed-Solomon	B-Error_Name
error	I-Error_Name
correction	I-Error_Name
.	O
</s>
<s>
The	O
required	O
media	B-Protocol
access	I-Protocol
control	I-Protocol
is	O
taken	O
from	O
IEEE	O
802.15.4	O
,	O
a	O
radio	O
standard	O
.	O
</s>
<s>
In	O
the	O
protocol	O
,	O
6loWPAN	B-Protocol
has	O
been	O
chosen	O
to	O
adapt	O
IPv6	B-Protocol
an	O
internet	O
network	O
layer	O
to	O
constrained	O
environments	O
which	O
is	O
Power	B-Device
line	I-Device
communications	I-Device
.	O
</s>
<s>
6loWPAN	B-Protocol
integrates	O
routing	O
,	O
based	O
on	O
the	O
mesh	B-Architecture
network	I-Architecture
LOADng	O
,	O
header	O
compression	O
,	O
fragmentation	O
and	O
security	O
.	O
</s>
<s>
With	O
the	O
use	O
of	O
IPv6	B-Protocol
,	O
G3-PLC	O
enables	O
communication	O
between	O
meters	O
,	O
grid	O
actuators	O
as	O
well	O
as	O
smart	O
objects	O
.	O
</s>
<s>
In	O
December	O
2011	O
,	O
G3	O
PLC	O
technology	O
was	O
recognised	O
as	O
an	O
international	O
standard	O
at	O
ITU	O
in	O
Geneva	O
where	O
it	O
is	O
referenced	O
as	O
G.9903	O
,	O
Narrowband	O
orthogonal	B-Protocol
frequency	I-Protocol
division	I-Protocol
multiplexing	I-Protocol
power	B-Device
line	I-Device
communication	I-Device
transceivers	O
for	O
G3-PLC	O
networks	O
.	O
</s>
<s>
Power	B-Device
line	I-Device
communications	I-Device
can	O
also	O
be	O
used	O
in	O
a	O
home	O
to	O
interconnect	O
home	O
computers	O
and	O
peripherals	O
,	O
and	O
home	O
entertainment	O
devices	O
that	O
have	O
an	O
Ethernet	O
port	O
.	O
</s>
<s>
The	O
widely	O
deployed	O
powerline	B-Device
networking	I-Device
standard	O
are	O
from	O
HD-PLC	B-Protocol
Allianceand	O
HomePlug	O
Powerline	O
Alliance	O
.	O
</s>
<s>
HD-PLC	B-Protocol
,	O
and	O
HomePlug	O
AV	O
which	O
is	O
the	O
most	O
current	O
of	O
the	O
HomePlug	O
specifications	O
were	O
adopted	O
by	O
the	O
IEEE	O
1901	O
group	O
as	O
baseline	O
technologies	O
for	O
their	O
standard	O
,	O
published	O
30	O
December	O
2010	O
.	O
</s>
<s>
Other	O
companies	O
and	O
organizations	O
back	O
different	O
specifications	O
for	O
power	O
line	O
home	O
networking	O
and	O
these	O
include	O
the	O
Universal	O
Powerline	O
Association	O
,	O
SiConnect	O
,	O
Xsilon	O
,	O
and	O
the	O
ITU-T	O
'	O
s	O
G.hn	B-General_Concept
(	O
HomeGrid	O
)	O
specification	O
.	O
</s>
<s>
In	O
such	O
use	O
cases	O
,	O
power	B-Device
line	I-Device
communication	I-Device
technologies	O
can	O
also	O
be	O
used	O
and	O
provides	O
the	O
same	O
advantage	O
of	O
reusing	O
existing	O
cables	O
.	O
</s>
<s>
HD-PLC	B-Protocol
has	O
developed	O
a	O
multi-hop	O
technology	O
that	O
can	O
be	O
used	O
to	O
build	O
large-scale	O
networks	O
.	O
</s>
<s>
In	O
addition	O
,	O
the	O
4th-generation	O
HD-PLC	B-Protocol
technology	O
provides	O
multiple	O
channels	O
,	O
which	O
enables	O
high-speed	O
and	O
long-range	O
communication	O
by	O
selecting	O
the	O
optimal	O
channel	O
.	O
</s>
<s>
Broadband	B-General_Concept
over	O
power	O
line	O
(	O
BPL	O
)	O
is	O
a	O
system	O
to	O
transmit	O
two-way	O
data	O
over	O
existing	O
AC	O
MV	O
(	O
medium	O
voltage	O
)	O
electrical	O
distribution	O
wiring	O
,	O
between	O
transformers	O
,	O
and	O
AC	O
LV	O
(	O
low	O
voltage	O
)	O
wiring	O
between	O
transformer	O
and	O
customer	O
outlets	O
(	O
typically	O
100	O
to	O
240	O
V	O
)	O
.	O
</s>
<s>
Modern	O
BPL	O
employs	O
Wavelet-OFDM	O
,	O
FFT-OFDM	O
,	O
or	O
frequency-hopping	B-Protocol
spread	I-Protocol
spectrum	I-Protocol
to	O
avoid	O
using	O
those	O
frequencies	O
actually	O
in	O
use	O
,	O
though	O
early	O
pre-2010	O
BPL	O
standards	O
did	O
not	O
.	O
</s>
<s>
In	O
North	O
America	O
it	O
is	O
used	O
in	O
some	O
places	O
(	O
Washington	O
Island	O
,	O
WI	O
,	O
for	O
instance	O
)	O
but	O
is	O
more	O
generally	O
used	O
by	O
electric	O
distribution	O
utilities	O
for	O
smart	B-Device
meters	I-Device
and	O
load	O
management	O
.	O
</s>
<s>
Since	O
the	O
ratification	O
of	O
the	O
IEEE	O
1901	O
(	O
HD-PLC	B-Protocol
,	O
HomePlug	O
)	O
LAN	B-General_Concept
standard	O
and	O
its	O
widespread	O
implementation	O
in	O
mainstream	O
router	O
chipsets	O
,	O
the	O
older	O
BPL	O
standards	O
are	O
not	O
competitive	O
for	O
communication	O
between	O
AC	O
outlets	O
within	O
a	O
building	O
,	O
nor	O
between	O
the	O
building	O
and	O
the	O
transformer	O
where	O
MV	O
meets	O
LV	O
lines	O
.	O
</s>
<s>
While	O
these	O
may	O
interfere	O
with	O
radio	O
astronomy	O
when	O
used	O
outdoors	O
,	O
the	O
advantages	O
of	O
speeds	O
competitive	O
with	O
fibre	B-Architecture
optic	I-Architecture
cables	O
without	O
new	O
wiring	O
are	O
likely	O
to	O
outweigh	O
that	O
.	O
</s>
<s>
Because	O
the	O
underlying	O
propagation	O
mode	O
is	O
extremely	O
broadband	B-General_Concept
(	O
in	O
the	O
technical	O
sense	O
)	O
,	O
it	O
can	O
operate	O
anywhere	O
in	O
the	O
20MHz20GHz	O
region	O
.	O
</s>
<s>
Two	O
distinctly	O
different	O
sets	O
of	O
standards	O
apply	O
to	O
powerline	B-Device
networking	I-Device
as	O
of	O
early	O
2010	O
.	O
</s>
<s>
The	O
IEEE	O
1901	O
includes	O
HD-PLC	B-Protocol
and	O
HomePlug	O
AV	O
as	O
baseline	O
technologies	O
.	O
</s>
<s>
On	O
October	O
2009	O
,	O
the	O
ITU-T	O
adopted	O
Recommendation	O
G.hn/G.9960	O
as	O
a	O
standard	O
of	O
networks	O
for	O
high-speed	O
powerline	O
,	O
coax	O
,	O
and	O
phoneline	O
communications	O
.	O
</s>
<s>
In	O
July	O
2009	O
,	O
the	O
IEEE	O
Power	B-Device
line	I-Device
Communication	I-Device
Standards	O
Committee	O
approved	O
its	O
draft	O
standard	O
for	O
broadband	B-General_Concept
over	O
power	O
lines	O
.	O
</s>
<s>
The	O
IEEE	O
1901	O
final	O
standard	O
was	O
published	O
on	O
30	O
December	O
2010	O
,	O
and	O
included	O
features	O
from	O
HomePlug	O
and	O
HD-PLC	B-Protocol
.	O
</s>
<s>
Power	B-Device
line	I-Device
communication	I-Device
via	O
IEEE	O
1901	O
and	O
IEEE	O
1905	O
compliant	O
devices	O
is	O
indicated	O
by	O
the	O
nVoy	O
certification	O
all	O
major	O
vendors	O
of	O
such	O
devices	O
committed	O
to	O
in	O
2013	O
.	O
</s>
<s>
NIST	O
has	O
included	O
IEEE	O
1901	O
(	O
HD-PLC	B-Protocol
,	O
HomePlug	O
AV	O
)	O
and	O
ITU-T	B-General_Concept
G.hn	I-General_Concept
as	O
"	O
Additional	O
Standards	O
Identified	O
by	O
NIST	O
Subject	O
to	O
Further	O
Review	O
"	O
for	O
the	O
Smart	B-Architecture
grid	I-Architecture
in	O
the	O
United	O
States	O
.	O
</s>
<s>
IEEE	O
also	O
came	O
up	O
with	O
a	O
low-frequency	O
standard	O
for	O
long-distance	O
smart	B-Architecture
grids	I-Architecture
called	O
IEEE	O
1901.2	O
in	O
2013	O
.	O
</s>
