Specifications

DRM - Dynamic Radio Management
Summit WM20 Technical Reference Guide, Software Version 4.288
Other sources of RF Interference
RF quality can also be affected by interference caused by other RF technologies and propagation
characteristics of the RF signal through and around objects.
Other devices operating in either the 2.4 GHz band or the 5GHz band can interfere with 802.11 data
transmission. These types of devices include equipment such as fluorescent lights, other wireless
technologies such as Bluetooth or cordless phones. Microwave equipment including microwave ovens
can interfere in different ways with 802.11 devices depending on how they use the RF spectrum.
An RF transmission through any object will cause interference in the form of reflection and refraction.
The amount of reflection or refraction will depend on the geometric and material properties of the
object. Metal objects will tend to reflect the signal, while wood, concrete, or water will tend to absorb
and refract (bend) the signal.
Refraction generally causes loss in signal power, while reflection causes a change in signal direction.
Refraction will cause a device to receive a signal at a reduced power level, thereby reducing the signal-
to-noise ratio (SNR). A large power reduction can cause the 802.11 client to lose data and potentially its
link to the Access Point.
Signal reflection can cause the wireless device to receive the same signal (or data packet) at a small time
delay. This multi-path interference can cause data transmission errors and if significant, can cause a
wireless device to lose its link with the Access Point.
The changes to the RF environment will occur dynamically. In the simplest case, people walking around
an office or doors being open or shut can change in the RF coverage. Most industries are prone to
dynamic RF changes, but some can be critically prone, such as:
● Hospitals – lots of body movement and equipment movement, including lead-lined curtains
● Education – students (people) – the number one source of absorption
● Public places – caused mostly by people, but include indoor signage from stores, mobile kiosks,
booths for convention centers, other wireless devices not controlled by the network administrator,
etc.
● Warehousing – addition and removal of inventory, and the equipment used to move the inventory
DRM Benefits
RF Management with DRM allows the HAPs to exchange RF information and dynamically adapt to
changes in the RF environment. It allows the WLAN to be installed in dense deployments while
avoiding interference issues.
DRM provides additional benefits which include:
● Highest available RF data rate. With the smart exchanges between HAPs, the WLAN ensures the
highest performance for the entire wireless network.
● RF redundancy. With a dense deployment, DRM provides dynamic redundancy when a Wireless AP
fails (e.g. power loss); HAPs can detect the loss of an adjacent Wireless AP and therefore increase
coverage dynamically to eliminate “dead spots”.
● Operational savings. With RF management, network administrators do not need to plan out the
channel assignment and the signal strength for every Summit Access Point. Also, with a dense
deployment, site surveys are no longer obligatory.