FRITZ!Box 6840 LTE – Service - Knowledge Base

FRITZ!Box 6840 LTE – Service

FRITZ!Box reports "Wireless LAN transmission quality increased by reduced channel bandwidth"

The speed of the wireless connection (WiFi) to the FRITZ!Box displayed by wireless devices such as computers, smartphones, or tablets, is significantly lower than the data rate possible with the wireless standard 802.11n. The following message is displayed in the event log of the FRITZ!Box:

  • "Wireless LAN transmission quality increased by reduced channel bandwidth (2.4 GHz)"

Cause

  • The FRITZ!Box recognizes when the wireless channels it uses in the 2.4 GHz frequency band are in heavy use by other wireless networks. To ensure stable wireless connections, it automatically reduces the channel bandwidth from 40 MHz to 20 MHz. This FRITZ!Box behavior is conform to wireless coexistence, which is part of the wireless standard 802.11n. Although wireless devices then display a lower data rate, the user data rate is increased because there is less interference and the wireless connection is no longer affected by constant retransmissions.

Note:The configuration procedure and notes on functions given in this guide refer to the latest FRITZ!OS for your FRITZ!Box.

Simply proceed as described below. After each measure, check whether the problem persists.

1 Enabling or refreshing the auto channel

When the auto channel is enabled, the FRITZ!Box checks the wireless environment and automatically selects the most suitable wireless channel settings. The allocation of the frequency band can change significantly over the course of the day, though. The FRITZ!Box does not refresh the auto channel as long as wireless devices are still connected with it. However, you can manually refresh the auto channel at any time:

  1. Click "Wireless" ("WLAN") in the FRITZ!Box user interface.
  2. Click "Radio Channel" in the "Wireless" ("WLAN") menu.
  3. Enable the option "Set radio channel settings automatically (recommended)".
  4. Click "Apply" to save the settings.

    Note:When you enable or refresh the auto channel, all wireless connections to the FRITZ!Box are cleared and automatically re-established.

  5. Click the "Refresh Auto Channel" button.

2 Establishing a wireless connection to the 5 GHz frequency band

The FRITZ!Box provides a wireless network either in the 2.4 GHz or the 5 GHz frequency band. The 5 GHz frequency band is less affected by interference. Therefore, switch to this frequency band if your wireless devices support the 5 GHz frequency band:

Note:Not all wireless devices support the 5 GHz frequency band.
FRITZ!WLAN Stick AC 430, FRITZ!WLAN Stick AC 860, and FRITZ!WLAN Stick N (v2) support the 5 GHz frequency band.

  1. Click "Wireless" ("WLAN") in the FRITZ!Box user interface.
  2. Click "Radio Channel" in the "Wireless" ("WLAN") menu.
  3. Enable the option "Adjust radio channel settings".
  4. Click "Additional Settings".
  5. Select the standard "802.11n+a" from the "Wireless standard" drop-down list.
  6. Click "Apply" to save the settings.
  7. Re-establish the wireless connection to the FRITZ!Box.

Now wireless connections to the FRITZ!Box are established with the maximum possible data rate.

Note:If the message "Wireless LAN transmission quality increased by reduced channel bandwidth [...]" is still displayed in the event log of the FRITZ!Box, this is due to the heavy use by wireless networks in the vicinity.