Qbss Support; Theory Of Operations - Motorola AP-7131 Product Reference Manual

1-20 AP-7131 Access Point Product Reference Guide

1.1.38 QBSS Support

Each access point radio can be configured to optionally allow the access point to communicate
channel usage data to associated devices and define the beacon interval used for channel utilization
transmissions. The QBSS load represents the percentage of time the channel is in use by the access
point and the access point's station count. This information is very helpful in assessing the access
point's overall load on a channel, its availability for additional device associations and multi media
traffic support.
For information on enabling QBSS and defining the channel utilization transmission interval, see
Configuring the 802.11a/n or 802.11b/g/n Radio on page 5-55.

1.2 Theory of Operations

To understand access point management and performance alternatives, users need familiarity with
functionality and configuration options. The access point includes features for different interface
connections and network management.
The access point uses electromagnetic waves to transmit and receive electric signals without wires.
Users communicate with the network by establishing radio links between mobile units (MUs) and
access points.
The access point uses DSSS (direct sequence spread spectrum) to transmit digital data from one
device to another. A radio signal begins with a carrier signal that provides the base or center
frequency. The digital data signal is encoded onto carriers using a DSSS chipping algorithm. The
radio signal propagates into the air as electromagnetic waves. A receiving antenna (on the MU) in
the path of the waves absorbs the waves as electrical signals. The receiving MU interprets
(demodulates) the signal by reapplying the direct sequence chipping code. This demodulation results
in the original digital data.
The access point uses its environment (the air and certain objects) as the transmission medium.The
access point can either transmit in the 2.4 to 2.5-GHz frequency range (802.11b/g/n radio) or the
5 GHz frequency range (802.11a/n radio), the actual range is country-dependent. Motorola devices,
like other Ethernet devices, have unique, hardware encoded Media Access Control (MAC) or IEEE
addresses. MAC addresses determine the device sending or receiving data. A MAC address is a
48-bit number written as six hexadecimal bytes separated by colons. For example: 00:A0:F8:24:9A:C8