How to Improve WiFi Connectivity

Problem

Your WiFi connection is unstable, or weak, or both.

Environment

UDC with IGEL Linux v5??? or IGEL OS??? or higher???
UD Pocket IGEL Linux v5??? or IGEL OS??? or higher???

Possible Causes and Solutions

There are many circumstances and parameters which influence the quality of a device's WiFi connection. To find a suitable solution to your problem, check out the following collection of possible causes and suggested solutions, workarounds and hints for debugging.

Several Access Points (APs) Are Using the Same Channel

If more than one Access Points visible to the thin client are using the same WiFi channel, interference issues may arise.

->Reconfigure the Access Point (AP) in question to use different channels.

Roaming within One Network (Same SSID)

When the device is configured to roam within its network, it tries to make sure that it is using the strongest/nearest Access Point (AP) within its network. Dependent on the given situation, it might be feasible to disable or to optimize roaming.

Avoid Roaming

->In the Setup, go to System > Registry > network > interfaces > wirelesslan > device0 > lock_initial (Registry key: network.interfaces.wirelesslan.device0.lock_initial) and activate Avoid roaming within the same network.

If roaming is deactivated, System > Registry > network > interfaces > wirelesslan > device0 > bgscan > module should be set to none.

Select the Access Point with the Best Signal

With the following setting, the thin client selects the Access Point that emits the best signal when the device starts up.

->In the Setup, go to System > Registry > network > interfaces > wirelesslan > device0 > bssid (Registry key: network.interfaces.wirelesslan.device0.bssid) and enter bestsignal in the BSSID field.

Automatic Roaming

Automatic roaming is feasible if the device is moved around frequently, and several Access Points are available.

In the following example, the device is configured to start scanning for another Access Point 10 seconds after the signal of the current Access Point has dropped below -78 db, while a routine scan is executed every 60 seconds, :

In the Setup, go to System > Registry > network > interfaces > wirelesslan > device0 > bgscan > module (Registry key: network.interfaces.wirelesslan.device0.bgscan.module) and select simple.
Set System > Registry > network > interfaces > wirelesslan > device0 > bgscan > module > simple > long_interval (Registry key: network.interfaces.wirelesslan.device0.bgscan.module.simple.long_interval) to 60.
Set System > Registry > network > interfaces > wirelesslan > device0 > bgscan > module > simple > short_interval (Registry key: network.interfaces.wirelesslan.device0.bgscan.module.simple.short_interval) to 10.
Set System > Registry > network > interfaces > wirelesslan > device0 > bgscan > module > simple > signal_strength (Registry key: network.interfaces.wirelesslan.device0.bgscan.module.simple.signal_strength) to -78.

40 MHz Bandwidth in the 2.4 GHz Band

With some Access Points, it may be feasible to disable the 40 MHz bandwidth in the 2.4 GHz band.

->In the Setup, go to System > Registry > network > interfaces > wirelesslan > device0 > driver > cfg80211 > cfg80211_disable_40mhz_24ghz (Registry key: network.interfaces.wirelesslan.device0.driver.cfg80211.cfg80211_disable_40mhz_24ghz) and deactivate Disable 40 MHz channel bandwidth in 2.4 GHz band.

High Throughput Option

In some environments, the high throughput functionality built into the driver may not produce optimal results. You can disable this functionality and check if the connection has improved.

->In the Setup, go to System > Registry > network > interfaces > wirelesslan > device0 > driver > disable_ht (Registry key: network.interfaces.wirelesslan.device0.driver.disable_ht) and deactivate Disable HT.

2.4 GHz Band Only

In some environments, it might be better to use only the 2.4 GHz band.

->In the Setup, go to System > Registry > network > interfaces > wirelesslan > device0 > band (Registry key: network.interfaces.wirelesslan.device0.band) and select 2.4 GHz.

If one or more alternative WiFi networks (SSIDs) are configured, do the following for each alternative SSID:

->In the Setup, go to System > Registry > network > interfaces > wirelesslan > device0 > alt_ssid[number] > band (Registry key: network.interfaces.wirelesslan.device0.alt_ssid[number].band) and select 2.4 GHz.

Frame Aggregation

It might be helpful to disable the frame aggregation feature of IEEE 802.11n.

->Disable frame aggregation on your Access Point (AP).

On your Access Point, this feature may have a different name.

Also note that IGEL cannot give a guarantee that the Access Point will function properly after the suggested configuration changes.

WiFi Driver Scans And Selects Access Point

By default, the WPA supplicant initiates scanning and the selection of an Access Point. You can change this behavior and assign this task to the driver.

In the Setup, go to System > Registry > network > interfaces > wirelesslan > device0 > wpa > ap_scan (Registry key: network.interfaces.wirelesslan.device0.wpa.ap_scan) and select WLAN driver initiates scanning and AP selection.
Restart the thin client.

Whitelist of BSSIDs

You can restrict the number of Access Points to be scanned by creating a whitelist. This whitelist contains only the BSSIDs of those Access Points that the device should scan.

In the Setup, go to System > Registry > network > interfaces > wirelesslan > device0 > bssid_whitelist (Registry key: network.interfaces.wirelesslan.device0.bssid_whitelist) and enter the BSSIDs of those Access Points that should be scanned, separated by whitespaces.

Debugging

If none of the methods described above work, you can create a log file and send it to the IGEL Support Team.

In the Setup, go to System > Registry > network > interfaces > wirelesslan > device0 > wpa > debug (Registry key: network.interfaces.wirelesslan.deviceo.wpa.debug) and select very verbose.
Restart the thin client.
Send the file /tmp/wpa_debug.all to the IGEL Support Team.