<s>
In	O
telecommunications	O
,	O
point-to-multipoint	B-General_Concept
communication	I-General_Concept
(	O
P2MP	B-General_Concept
,	O
PTMP	B-General_Concept
or	O
PMP	O
)	O
is	O
communication	O
which	O
is	O
accomplished	O
via	O
a	O
distinct	O
type	O
of	O
one-to-many	B-Application
connection	O
,	O
providing	O
multiple	O
paths	O
from	O
a	O
single	O
location	O
to	O
multiple	O
locations	O
.	O
</s>
<s>
Point-to-multipoint	B-General_Concept
telecommunications	O
is	O
typically	O
used	O
in	O
wireless	O
Internet	O
and	O
IP	B-Application
telephony	I-Application
via	O
gigahertz	O
radio	O
frequencies	O
.	O
</s>
<s>
P2MP	B-General_Concept
systems	O
have	O
been	O
designed	O
with	O
and	O
without	O
a	O
return	O
channel	O
from	O
the	O
multiple	O
receivers	O
.	O
</s>
<s>
A	O
central	O
antenna	O
or	O
antenna	B-Algorithm
array	I-Algorithm
broadcasts	B-Operating_System
to	O
several	O
receiving	O
antennas	O
and	O
the	O
system	O
uses	O
a	O
form	O
of	O
time-division	B-Protocol
multiplexing	I-Protocol
to	O
allow	O
for	O
the	O
return	O
channel	O
traffic	O
.	O
</s>
<s>
In	O
contemporary	O
usage	O
,	O
the	O
term	O
point-to-multipoint	B-General_Concept
wireless	O
communications	O
relates	O
to	O
fixed	O
wireless	O
data	O
communications	O
for	O
Internet	O
or	O
voice	B-Application
over	I-Application
IP	I-Application
via	O
radio	O
or	O
microwave	B-Application
frequencies	O
in	O
the	O
gigahertz	O
range	O
.	O
</s>
<s>
Point-to-multipoint	B-General_Concept
is	O
the	O
most	O
popular	O
approach	O
for	O
wireless	O
communications	O
that	O
have	O
a	O
large	O
number	O
of	O
nodes	O
,	O
end	O
destinations	O
or	O
end	O
users	O
.	O
</s>
<s>
Point	B-General_Concept
to	I-General_Concept
Multipoint	I-General_Concept
generally	O
assumes	O
there	O
is	O
a	O
central	O
base	O
station	O
to	O
which	O
remote	O
subscriber	O
units	O
or	O
customer	O
premises	O
equipment	O
(	O
CPE	O
)	O
(	O
a	O
term	O
that	O
was	O
originally	O
used	O
in	O
the	O
wired	O
telephone	O
industry	O
)	O
are	O
connected	O
over	O
the	O
wireless	O
medium	O
.	O
</s>
<s>
Often	O
the	O
point	B-General_Concept
to	I-General_Concept
multipoint	I-General_Concept
links	O
are	O
installed	O
to	O
reduce	O
the	O
cost	O
of	O
infrastructure	O
and	O
increase	O
the	O
number	O
of	O
CPE	O
's	O
and	O
connectivity	O
.	O
</s>
<s>
Point-to-multipoint	B-General_Concept
wireless	O
networks	O
employing	O
directional	O
antennas	O
are	O
affected	O
by	O
the	O
hidden	B-General_Concept
node	I-General_Concept
problem	I-General_Concept
(	O
also	O
called	O
hidden	B-General_Concept
terminal	I-General_Concept
)	O
in	O
case	O
they	O
employ	O
a	O
CSMA/CA	O
medium	O
access	O
control	O
protocol	O
.	O
</s>
<s>
The	O
negative	O
impact	O
of	O
the	O
hidden	B-General_Concept
node	I-General_Concept
problem	I-General_Concept
can	O
be	O
mitigated	O
using	O
a	O
time-division	B-Protocol
multiple	O
access	O
(	O
TDMA	O
)	O
based	O
protocol	O
or	O
a	O
polling	O
protocol	O
rather	O
than	O
the	O
CSMA/CA	O
protocol	O
.	O
</s>
<s>
The	O
telecommunications	O
signal	O
in	O
a	O
point-to-multipoint	B-General_Concept
system	O
is	O
typically	O
bi-directional	O
,	O
TDMA	O
or	O
channelized	O
.	O
</s>
<s>
Systems	O
using	O
frequency-division	O
duplexing	O
(	O
FDD	O
)	O
offer	O
full-duplex	O
connections	O
between	O
base	O
station	O
and	O
remote	O
sites	O
,	O
and	O
time-division	B-Protocol
duplex	O
(	O
TDD	O
)	O
systems	O
offer	O
half-duplex	O
connections	O
.	O
</s>
<s>
Point-to-multipoint	B-General_Concept
systems	O
can	O
be	O
implemented	O
in	O
licensed	O
,	O
semi-licensed	O
or	O
unlicensed	O
frequency	O
bands	O
depending	O
on	O
the	O
specific	O
application	O
.	O
</s>
<s>
point-to-point	B-Architecture
and	O
point-to-multipoint	B-General_Concept
links	O
are	O
very	O
popular	O
in	O
the	O
wireless	O
industry	O
and	O
when	O
paired	O
with	O
other	O
high-capacity	O
wireless	O
links	O
or	O
technologies	O
such	O
as	O
free	O
space	O
optics	O
(	O
FSO	O
)	O
can	O
be	O
referred	O
to	O
as	O
backhaul	B-General_Concept
.	O
</s>
