Application Note

Power Level Adjustments
The radio power levels in the Netgear Wireless Switch are adjustable between 0 and 4, 0 being the
lowest value possible and 4 the highest.
Power assignment decisions are based on the AP’s coverage index. The benchmark used here is the
ideal-coverage index. The ideal-coverage index is the power setting that an AP should have for good
coverage. It is a configurable parameter on the WFS709TP.
The AP increases or decreases its power settings based on the difference between the value of its
current channel coverage index and the ideal-coverage index value. The power settings increment or
decrement by a single unit at any given time.
Likewise, if an AP fails, the power levels will be dynamically adjusted to fill in holes.
Power levels:
802.11B/G Band:
Level dB mW
0 0 1
1 11 13
2 14 25
3 17 50
4 20 100
802.11A Band:
Level dB mW
0 0 1
1 9 8
2 12 16
3 15 32
4 18 63
Channel Selection
APs operate most efficiently when they are the only AP on the channel. One of the tasks of the calibration
process is to choose channels to minimize channel overlap, as overlapping channels can corrupt data
transmissions by creating an “RF Collision”
Channel assignments vary by country due to localized regulations. Also, administrators can change which
channels will be used by the system.
In addition to the interference index, the APs use the free-channel index to determine the optimal channel
setting. The free-channel index is a configurable parameter on the WFS709TP used by an AP to qualify a
channel before moving to it. An AP chooses to move to a new channel only if its current channel
interference index is greater than the interference index on the new channel by a value greater than or
equal to the free-channel index. If this requirement is not met, the AP remains on the current channel.