Trango
Systems,
Inc
TL45
User
Manual
Rev
2.0r3
LT
‐
9037A
August
15,
2011
Page
8
Chapter
1
Overview
The
TrangoLINK
‐
45
is
a
point
‐
to
‐
point
(PtP)
wireless
Ethernet
transmission
system
which
provides
network
connectivity
at
speeds
up
to
45
Mbps
depending
on
the
transmission
distance
and
noise
floor.
The
TrangoLINK
‐
45
utilizes
OFDM
technology
and
is
designed
for
use
in
long
range
backhaul
and
wide
area
data
networking
applications.
Users
are
required
to
simply
specify
one
P5055M
unit
type
as
master
unit
(MU)
and
one
unit
as
remote
unit
(RU)
to
establish
a
link.
Each
unit
utilizes
power
‐
over
‐
Ethernet
(PoE)
and
is
designed
for
outdoor
environments.
The
cable
entry
point
can
accommodate
both
Shielded
twisted
pair
Cat5
(STP)
and
unshielded
twisted
pair
Cat5
(UTP),
with
the
addition
of
conduit
for
tower
mounting.
DFS
One
of
the
key
features
of
the
TrangoLINK
‐
45
is
that
it
has
Dynamic
Frequency
Selection
(DFS)
which
allows
it
to
be
operated
in
the
5.25
to
5.35
GHz
and
5.47
to
5.7
GHz
frequency
ranges
depending
upon
the
regulatory
requirements.
When
operating
in
these
frequencies
ranges
the
MU
will
monitor
the
channel
for
radar
transmissions
and
switch
to
a
new
channel
automatically
if
radar
is
detected.
The
RU
will
switch
to
the
new
channel
as
well
and
the
link
will
be
automatically
reconnected,
typically
in
about
1
minute.
Each
radio
unit
has
a
different
threshold
for
detecting
radar
that
corresponds
to
the
radio’s
antenna
gain.
For
the
P5055M
‐
19
‐
xx
models,
the
threshold
is
–46
dBm.
Any
radar
signal
arriving
at
the
antenna
on
the
operating
channel
that
has
an
amplitude
greater
than
–46
dBm
will
cause
the
MU
and
it’s
associated
RU
to
switch
to
a
randomly
selected
channel
that
is
tagged
as
a
DFS
channel
in
the
channel
table.
For
the
P5055M
‐
23
‐
xx
units,
the
threshold
is
is
–42
dBm,
and
for
the
P5055M
‐
EXT
‐
xx
units
the
threshold
is
–37
dBm.
IMPORTANT
NOTE:
When
operating
in
the
DFS
frequencies,
the
radio
units
will
use
automatic
transmit
power
control
(ATPC)
to
maintain
the
RSSI
at
a
level
of
approximately
–62
dBm.
For
very
short
link
distances
it
may
not
be
possible
for
the
transmit
power
to
be
reduced
below
the
Radar
detection
threshold
and
the
radio
may
not
be
able
to
establish
a
reliable
link.
Trango
recommends
that
careful
link
budget
planning
be
done
to
ensure
that
this
condition
does
not
exist.
OFDM
The
TrangoLINK
‐
45
platform
utilizes
Orthogonal
Frequency
Division
Duplex
(OFDM)
processing
which
offers
link
stability
and
performance
in
the
presence
of
multipath
interference
.
Adaptive
Modulation
One
of
the
key
advantages
of
the
TrangoLINK
‐
45
series
radio
platform
is
utilization
of
multiple
modulation
schemes
including
the
following:
•
Binary
Phase
Shift
Keying
(BPSK)
•
Quadrature
Phase
Shift
Keying
(QPSK)
•
16
Quadrature
Amplitude
Modulation
(16QAM)
•
64
Quadrature
Amplitude
Modulation
(64QAM)
The
TrangoLINK
‐
45
system
allows
individual
selection
of
the
upstream
and
downstream
modulation
schemes.
The
modulation
schemes
can
be
adjusted
manually
or
automatically
(automatic
rate
shifting)
for
changing
propagation
and
interference
conditions.
The
higher
order
modulation
schemes
(64QAM)
are
typically
deployed
at
reduced
ranges
while
lower
order
modulation
schemes
(BPSK)
are
implemented
at
long
distances.
