Icom AP-12 instruction manual Hidden wireless terminals, Communication channels

AP-12 MANAGER 4

DHidden wireless terminals

During Access Point mode communication as shown below, wireless LAN termi- nal [A] and [C] cannot communicate directly, even when both terminal [A] and [C] can access AP-12 [B].

In such a case, terminal [A] is a “Hidden wireless terminal” for [C], and terminal [C] is a “Hidden wireless terminal” for [A].

When terminal [A] is accessing AP-12 [B], for example, to prevent the communi- cation collision, the request-to-send (Rts) signal received by AP-12 [B] sends a clear-to-send (Cts) signal to both terminal [A] and [C] repeatedly. Then terminal [C] recognizes that AP-12 is busy, and forbidding to access to AP-12 [B].

Communication

collision

AP-12 [B] wirelless transmiissiion area

Ethernet LAN

A C

AP-12 B

wireless LAN [A]	wireless LAN [C]
wireless transmission area	wireless transmission area

D Communication channels

Set the communication channels of network groups at least four channels apart to	4
avoid interference if two or more access points are available in the wireless trans-
mission area.
Otherwise, interference may occur due to partial overlap in bandwidth as shown below.
Channel settings of 1-6-11, for example, eliminates the possibility of interference.

1 channel

6 channel

11 channel

2 channel

3 channel

7 channel

8 channel

4 channel

9 channel

5 channel

10 channel

2400 2410 2420 2430 2440 2450 2460 2470 2480 2490 2500

Frequency (MHz)

35