In spectrum analysis, the WLAN device ( AP ) detects different types of interference resources on wireless networks, and the spectrum analysis server ( AC ) analyzes the characteristics of collected wireless signals to identify and locate non-Wi-Fi devices, eliminating the impact of interference on WLANs.
Working process:
Spectrum analysis is implemented as follows:
The AP functions as the spectrum sampling engine to scan and sample the spectrum.
The AP periodically scans the wireless environment.
The AP obtains original spectrum sample data from channel scanning. Each spectrum sample data contains a group of subcarriers used for interference identification.
As a spectrum analyzer, the spectrum analysis module of the AP computes the sample data based on a certain algorithm to identify the non-Wi-Fi devices.
A common algorithm includes pulse signal extraction, pulse signal combining, pulse clustering, extraction of time signature, extraction of frequency characteristics, period calculation, and duty cycle calculation.
After the AP computes the characteristics, it can compare one or more characteristics with the interference source feature database to identify non-Wi-Fi devices.
Currently, the AC can identify baby monitors, Bluetooth devices, digital cordless phones (at 2.4 GHz frequency band only), wireless audio transmitters, wireless game controllers, and microwave ovens. Due to differences of individual devices, some of these non-Wi-Fi devices may not be identified.
The AP records the identified devices into the non-Wi-Fi device list, which you can query through command lines or on the web platform. If the type of an identified device is not in the non-Wi-Fi device list, the AP reports an alarm. If the type of the identified device is already in the list, the AP does not report an alarm. If the device ages, is manually deleted, or is removed from the detected range, the AP reports a clear alarm.The AP reports the data to the spectrum drawing server for interference visualization.
The AP can report the data to the spectrum drawing server directly or through the AC. Currently, Huawei only supports the eSight as the spectrum drawing server. You can also view the spectrum graphs through the web platform on the AC.
An important note is that the AP radio can work in two modes, normal and monitor.Normal mode: If the scan function is enabled on a radio, the radio can both analyse the radio and forward service traffic, but during the analyse period traffic might be affected.Monitor mode: If this mode is selected the radio can only scan but cannot forward services.
By default, it works in normal mode.
example of how to change working mode:
<AC6605> system-view
[AC6605] wlan
[AC6605-wlan-view] ap-group name office
[AC6605-wlan-ap-group-office] radio 0
[AC6605-wlan-group-radio-office/0] work-mode monitor
Configuration example:
http://support.huawei.com/hedex/pages/EDOC1000153688AEG06285/04/EDOC1000153688AEG06285/04/resources/dc/dc_wlan_example_spectrum_0001_copyto.html?ft=0&fe=10&hib=10.1.11.7.1&id=dc_wlan_example_spectrum_0001&text=Example for Configuring Spectrum Analysis&docid=EDOC1000153688
Another thing you could do is change from using a group of APs as the spectrum analyzer to just specific APs, using the below configuration:
<AC6605>system-view
[AC6605]wlan
[AC6605-wlan-view]ap-id 1
[AC6605-wlan-ap-1]radio 0
[AC6605-wlan-radio-1/0]spectrum-analysis enable
