D-Link DWL-3600AP Administrator's Manual page 61

Unified Access Point Administrator's Guide
Field Description
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 channel 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 The 802.11n specification allows a 40‐MHz‐wide channel in addition to the legacy 20‐
(802.11n modes MHz channel available with other modes. The 40‐MHz channel enables higher data rates
only) 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 This setting can be changed only when the channel bandwidth is set to 40 MHz. A 40‐
(802.11n modes MHz channel can be considered to consist of two 20‐MHz channels that are contiguous
only) 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 — S et the Primary Channel as the upper 20‐MHz channel in the 40‐MHz band.
• Lower — S et the Primary Channel as the lower 20‐MHz channel in the 40‐MHz band.
Short Guard This field is available only if the selected radio mode includes 802.11n.
Interval Supported
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 — T he AP transmits data using a 400 ns guard Interval when communicating with
• No — T he 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 — T he AP transmits the same data stream on multiple antennas at the same time.
• Off — T he AP does not transmits the same data on multiple antennas.
D-Link
November 2011
Table 19: Radio Settings (Cont.)
clients that also support the short guard interval.
Modifying Radio Settings
Unified Access Point Administrator's Guide
Page 61