<s>
Radio	B-Device
over	I-Device
fiber	I-Device
(	O
RoF	O
)	O
or	O
RF	O
over	O
fiber	O
(	O
RFoF	O
)	O
refers	O
to	O
a	O
technology	O
whereby	O
light	O
is	O
modulated	B-Application
by	O
a	O
radio	O
frequency	O
signal	O
and	O
transmitted	O
over	O
an	O
optical	B-Architecture
fiber	I-Architecture
link	O
.	O
</s>
<s>
Applications	O
range	O
from	O
the	O
transmission	O
of	O
mobile	O
radio	O
signals	O
(	O
3G	B-Architecture
,	O
4G	B-Architecture
,	O
5G	O
and	O
WiFi	O
)	O
and	O
the	O
transmission	O
of	O
cable	O
television	O
signals	O
(	O
CATV	B-Protocol
)	O
to	O
the	O
transmission	O
of	O
RF	O
L-Band	O
signals	O
in	O
ground	O
stations	O
for	O
satellite	B-Application
communications	O
.	O
</s>
<s>
Signals	O
transmitted	O
on	O
optical	B-Architecture
fiber	I-Architecture
attenuate	O
much	O
less	O
than	O
through	O
other	O
media	O
like	O
metal	O
cables	O
or	O
wireless	O
media	O
.	O
</s>
<s>
By	O
using	O
optical	B-Architecture
fiber	I-Architecture
,	O
the	O
radio	O
signals	O
can	O
gap	O
larger	O
transmission	O
distances	O
,	O
reducing	O
the	O
need	O
of	O
additional	O
repeaters	O
or	O
amplifiers	O
.	O
</s>
<s>
In	O
other	O
words	O
,	O
radio	O
signals	O
are	O
carried	O
over	O
fiber-optic	B-Architecture
cable	I-Architecture
.	O
</s>
<s>
Although	O
radio	O
transmission	O
over	O
fiber	O
is	O
used	O
for	O
multiple	O
purposes	O
,	O
such	O
as	O
in	O
cable	O
television	O
(	O
CATV	B-Protocol
)	O
networks	O
and	O
in	O
satellite	B-Application
base	O
stations	O
,	O
the	O
term	O
RoF	O
is	O
usually	O
applied	O
when	O
this	O
is	O
done	O
for	O
wireless	O
access	O
.	O
</s>
<s>
The	O
advantage	O
is	O
that	O
the	O
equipment	O
for	O
WiFi	O
,	O
5G	O
and	O
other	O
protocols	O
can	O
be	O
centralized	O
in	O
one	O
place	O
,	O
with	O
remote	O
antennas	O
attached	O
via	O
fiber	B-Architecture
optic	I-Architecture
serving	O
all	O
protocols	O
.	O
</s>
<s>
An	O
important	O
application	O
of	O
RoF	O
is	O
its	O
use	O
to	O
provide	O
wireless	O
coverage	O
in	O
the	O
area	O
where	O
wireless	O
backhaul	B-General_Concept
link	O
is	O
not	O
possible	O
.	O
</s>
<s>
Ng'oma	O
,	O
“	O
Radio-over-Fibre	B-Device
Technology	O
for	O
Broadband	O
Wireless	O
.	O
</s>
<s>
Fiber	B-Architecture
optics	I-Architecture
are	O
designed	O
to	O
handle	O
gigabits/second	O
speeds	O
which	O
means	O
they	O
will	O
be	O
able	O
to	O
handle	O
speeds	O
offered	O
by	O
future	O
generations	O
of	O
networks	O
for	O
years	O
to	O
come	O
.	O
</s>
<s>
New	O
RoF	O
techniques	O
that	O
support	O
MIMO-enabled	O
wireless	O
services	O
,	O
notably	O
4G/5G	O
mobile	O
and	O
802.11	O
WLAN	O
standards	O
,	O
have	O
also	O
been	O
proposed	O
.	O
</s>
<s>
In	O
Satellite	B-Application
Communications	O
RF-over-fiber	O
technology	O
is	O
employed	O
to	O
transmit	O
,	O
mainly	O
RF	O
signals	O
in	O
the	O
L-Band	O
frequency	O
range	O
(	O
950MHz	O
to	O
2150MHz	O
)	O
,	O
between	O
a	O
central	O
control	O
room	O
and	O
a	O
satellite	B-Application
antenna	O
at	O
a	O
satellite	B-Application
earth	O
station	O
.	O
</s>
<s>
With	O
the	O
use	O
of	O
DWDM	O
RF-over-Fiber	O
systems	O
even	O
the	O
low	O
loss	O
bi-directional	O
transmission	O
of	O
multiple	O
RF	O
signals	O
over	O
one	O
optical	B-Architecture
fiber	I-Architecture
with	O
transmission	O
distances	O
up	O
to	O
100km	O
is	O
enabled	O
.	O
</s>
<s>
State-of-the	O
art	O
satellite	B-Application
communication	O
systems	O
at	O
the	O
highest	O
data	O
rates	O
are	O
operated	O
on	O
the	O
Ka	O
band	O
.	O
</s>
<s>
Content	O
providers	O
may	O
transport	O
their	O
entire	O
CATV	B-Protocol
channel	O
lineup	O
over	O
a	O
single-fiber	O
optic	O
cable	O
,	O
because	O
this	O
way	O
they	O
can	O
transport	O
the	O
signal	O
for	O
hundreds	O
of	O
km	O
.	O
</s>
<s>
It	O
works	O
like	O
this	O
:	O
An	O
electrical	O
RF	O
signal	O
usually	O
in	O
the	O
range	O
of	O
54	O
–	O
870MHz	O
is	O
converted	O
to	O
modulated	B-Application
light	O
using	O
RF	O
1310nm	O
or	O
1550nm	O
laser	O
optics	O
.	O
</s>
<s>
The	O
light	O
travels	O
over	O
single-mode	O
fiber	O
to	O
the	O
fiber	B-Architecture
optic	I-Architecture
RF	O
receiver	O
where	O
is	O
converted	O
back	O
to	O
electrical	O
RF	O
.	O
</s>
<s>
1550nm	O
is	O
more	O
popular	O
because	O
it	O
has	O
less	O
losses	O
in	O
the	O
fiber	O
and	O
by	O
using	O
fiber-optic	B-Architecture
amplifier	O
known	O
as	O
EDFA	O
it	O
is	O
possible	O
to	O
extend	O
the	O
transport	O
distance	O
.	O
</s>
