Specifications

DRM - Dynamic Radio Management

Summit WM Series WLAN Switch and Altitude Access Point Software Version 4.1 Technical Reference Guide

Figure 20: Reduction of co-channel interference using DRM-enabled APs

Now consider the case for DRM’s standard RF mode. The data Tx range from each AP is kept as low as

possible give the active clients. The area of co-channel interference in the middle of the APs is now

reduced to just co-channel interference for beacons. Beacons are regular traffic but are only sent on a

typical interval of every 0.1 seconds. Also, for co-channel interference from beacons to occur in the

center area the beacons from the co-channel APs would have to be exactly synchronized. Given the

infrequency of the beacons and the probability of an exact synchronization between co-channel APs

then it is fair to say that the dynamic RF ability of DRM’s standard mode helps significantly clean up

the co-channel interference in the center of this example diagram.

Supporting New Clients

A key characteristic of DRM Power control is how it handles new clients. When a client first associates,

DRM increases the transmit power for data frames to full power. This is done because DRM does not

know the status of the client when it first associates. DRM then evaluates the clients needs and adjusts

the transmit power to support it. If the client is far away, DRM provides more power to support it. If

the client is very close, the transmit power for data traffic is reduced significantly to minimize

interference.

RF Domain

DRM adjusts power to APs that are part of its network. Another AP is defined as being part of this

network if the SSID matches the SSID of this AP. If the APs support multiple SSIDs, then the APs are

considered part of the same network if any of the SSIDs match.

If APs are configured to suppress their SSIDs, none of the APs can determine which APs are part of the

same network. To overcome this issue, DRM has introduced the concept of an RF Domain. The RF

Domain creates a set of APs that are part of the same wireless network. To establish an RF Domain, each

AP that is to be included must have a new field added to its configuration, the RF Domain. This field is