User's Manual

Wireless Array
Configuring the Wireless Array 313
Procedure for Configuring Global 802.11n IAP Settings
1. 802.11ac Mode: Select Enabled to allow the Array to operate in 802.11ac
mode. If you select Disabled, then 802.11ac operation is disabled on the
Array.
2. 80 MHz Guard interval: This is the length of the interval between
transmission of symbols (the smallest unit of data transfer) when you are
using 80MHz bonded channels. (See “Channel Bonding” on page 40 and
“Short Guard Interval” on page 41) Select Short to increase the data
transmission rate by decreasing wait intervals in signal transmission.
Select Long to use the standard interval. The default is Short. See “Short
Guard Interval” on page 41.
3. Max MCS: Select the highest Modulation and Coding Scheme level that
may be used with 1, 2, or 3 Spatial Streams. This setting may be used to
limit the highest level of modulation to 64-QAM, or allow 256-QAM with
its higher data rate. It also determines the coding scheme used for error
correction. Higher MCS levels allocate fewer bits to error correction, and
thus a higher proportion is used for data transfer. The default Max MCS
value is MCS9.
The higher the MCS values, the higher the data rate, as shown in 802.11ac
Supported Rates, below. Higher MCS levels require higher signal-to-
noise ratios (i.e., a less noisy environment) and shorter transmission
distances.
The maximum number of separate data streams that may be transmitted
by the antennas of each IAP is determined by whether the XR Series
Array has 2x2 or 3x3 radios. For a device that has 2x2 radios, such as the
XR-620, the settings for three spatial streams are not shown.See “Multiple
Data Streams — Spatial Multiplexing” on page 39.
4. 802.11ac Supported Rates: This list shows the optimum data rates that
can be expected, based on the number of spatial streams that a station can
handle, and on your settings for Max MCS, Guard Interval, and the use of
bonded channels, up to 80MHz wide.