Modifying
Radio
Settings
D-Link
Unified
Access
Point
Administrator’s
Guide
November
2011
Page
61
Unified
Access
Point
Administrator’s
Guide
Channel
Select
the
Channel
.
The
range
of
available
channels
is
determined
by
the
mode
of
the
radio
interface
and
the
country
code
setting.
If
you
select
Auto
for
the
channel
setting,
the
AP
scans
available
channels
and
selects
a
channel
where
no
traffic
is
detected.
The
c
hannel
defines
the
portion
of
the
radio
spectrum
the
radio
uses
for
transmitting
and
receiving.
Each
mode
offers
a
number
of
channels,
depending
on
how
the
spectrum
is
licensed
by
national
and
transnational
authorities
such
as
the
Federal
Communications
Commission
(FCC)
or
the
International
Telecommunication
Union
(ITU
‐
R).
When
automatic
channel
assignment
is
enabled
on
the
Channel
Management
page
for
Clustering,
the
channel
policy
for
the
radio
is
automatically
set
to
static
mode,
and
the
Auto
option
is
not
available
for
the
Channel
field.
This
allows
the
automatic
channel
feature
to
set
the
channels
for
the
radios
in
the
cluster.
Channel
Bandwidth
(802.11n
modes
only)
The
802.11n
specification
allows
a
40
‐
MHz
‐
wide
channel
in
addition
to
the
legacy
20
‐
MHz
channel
available
with
other
modes.
The
40
‐
MHz
channel
enables
higher
data
rates
but
leaves
fewer
channels
available
for
use
by
other
2.4
GHz
and
5
GHz
devices.
Set
the
field
to
20
‐
MHz
to
restrict
the
use
of
the
channel
bandwidth
to
a
20
‐
MHz
channel.
Primary
Channel
(802.11n
modes
only)
This
setting
can
be
changed
only
when
the
channel
bandwidth
is
set
to
40
MHz.
A
40
‐
MHz
channel
can
be
considered
to
consist
of
two
20
‐
MHz
channels
that
are
contiguous
in
the
frequency
domain.
These
two
20
‐
MHz
channels
are
often
referred
to
as
the
Primary
and
Secondary
channels.
The
Primary
Channel
is
used
for
802.11n
clients
that
support
only
a
20
‐
MHz
channel
bandwidth
and
for
legacy
clients.
Select
one
of
the
following
options:
• Upper
—
Set
the
Primary
Channel
as
the
upper
20
‐
MHz
channel
in
the
40
‐
MHz
band.
• Lower
—
Set
the
Primary
Channel
as
the
lower
20
‐
MHz
channel
in
the
40
‐
MHz
band.
Short
Guard
Interval
Supported
This
field
is
available
only
if
the
selected
radio
mode
includes
802.11n.
The
guard
interval
is
the
dead
time,
in
nanoseconds,
between
OFDM
symbols.
The
guard
interval
prevents
Inter
‐
Symbol
and
Inter
‐
Carrier
Interference
(ISI,
ICI).
The
802.11n
mode
allows
for
a
reduction
in
this
guard
interval
from
the
a
and
g
definition
of
800
nanoseconds
to
400
nanoseconds.
Reducing
the
guard
interval
can
yield
a
10%
improvement
in
data
throughput.
Select
one
of
the
following
options:
• Yes
—
The
AP
transmits
data
using
a
400
ns
guard
Interval
when
communicating
with
clients
that
also
support
the
short
guard
interval.
• No
—
The
AP
transmits
data
using
an
800
ns
guard
interval.
STBC
Mode
This
field
is
available
only
if
the
selected
radio
mode
includes
802.11n.
Space
Time
Block
Coding
(STBC)
is
an
802.11n
technique
intended
to
improve
the
reliability
of
data
transmissions.
The
data
stream
is
transmitted
on
multiple
antennas
so
the
receiving
system
has
a
better
chance
of
detecting
at
least
one
of
the
data
streams.
Select
one
of
the
following
options:
• On
—
The
AP
transmits
the
same
data
stream
on
multiple
antennas
at
the
same
time.
• Off
—
The
AP
does
not
transmits
the
same
data
on
multiple
antennas.
Table
19:
Radio
Settings
(Cont.)
Field
Description
