
Configuring the Wireless AP
SCALANCE WLC711
3-6 C79000-G8976-C260-03, 07/2012, User Guide, V8.11
Shortened Guard Interval
The purpose of the guard interval is to introduce immunity to propagation delays, echoes and
reflections of symbols in orthogonal frequency division multiplexing (OFDM) — a method by
which information is transmitted via a radio signal in Wireless APs.
In OFDM, the beginning of each symbol is preceded by a guard interval. As long as the echoes fall
within this interval, they will not affect the safe decoding of the actual data, as data are only
interpreted outside the guard interval. Longer guard periods reduce the channel efficiency. The
802.11n AP provides reduced guard periods, thereby increasing the throughput.
MAC Enhancements
The 802.11n AP also has an improved MAC layer protocol that reduces overhead (in the MAC
layer protocol) and contention losses. This results in increased throughput.
Models
The Wireless 802.11n AP is available in the following models:
• SCALANCE W786C-2 RJ45 — Six external antennas
• SCALANCE W786C-2IA RJ45 — Six internal antennas
• SCALANCE W788C-2 RJ45 — Six external antennas
• SCALANCE W788C-2 M12 — Six external antennas
Environment
With the exception of WS-W786C, Wireless 802.11n APs cannot be deployed in an outdoor
environment.
SCALANCE IWLAN 802.11n AP’s Radios
The SCALANCE IWLAN 802.11n AP is equipped with two radios — Radio 1 and Radio 2. The
following is a block diagram of the SCALANCE IWLAN 802.11n AP equipped with external
antennas.
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