dchao99
Posts: 45
Joined: Fri Jan 15, 2016 9:26 pm

RPi3: WiFi Channel 11 Problem

Fri Mar 25, 2016 10:04 pm

When my country code is set to the US, and my USA AP is set to channel 11.
The onboard WiFi performance become very sluggish (ie. AP gets disconnected, lost packets, very large latency....)
I think there is a problem with the brcm43430 driver when working with channel 11.
The problem goes away when I set the channel to 6.

Code: Select all

$ iwlist wlan0 frequency
wlan0     11 channels in total; available frequencies :
          Channel 01 : 2.412 GHz
          Channel 02 : 2.417 GHz
          Channel 03 : 2.422 GHz
          Channel 04 : 2.427 GHz
          Channel 05 : 2.432 GHz
          Channel 06 : 2.437 GHz
          Channel 07 : 2.442 GHz
          Channel 08 : 2.447 GHz
          Channel 09 : 2.452 GHz
          Channel 10 : 2.457 GHz
          Channel 11 : 2.462 GHz
          Current Frequency:2.462 GHz (Channel 11)

Code: Select all

$ dmesg
[    7.581230] cfg80211: Calling CRDA for country: US
[    7.595844] cfg80211: Regulatory domain changed to country: US
[    7.595856] cfg80211:  DFS Master region: FCC
[    7.595862] cfg80211:   (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp), (dfs_cac_time)
[    7.595869] cfg80211:   (2402000 KHz - 2472000 KHz @ 40000 KHz), (N/A, 3000 mBm), (N/A)
[    7.595877] cfg80211:   (5170000 KHz - 5250000 KHz @ 80000 KHz, 160000 KHz AUTO), (N/A, 1700 mBm), (N/A)
[    7.595884] cfg80211:   (5250000 KHz - 5330000 KHz @ 80000 KHz, 160000 KHz AUTO), (N/A, 2300 mBm), (0 s)
[    7.595890] cfg80211:   (5735000 KHz - 5835000 KHz @ 80000 KHz), (N/A, 3000 mBm), (N/A)
[    7.595897] cfg80211:   (57240000 KHz - 63720000 KHz @ 2160000 KHz), (N/A, 4000 mBm), (N/A)

asandford
Posts: 1997
Joined: Mon Dec 31, 2012 12:54 pm
Location: Waterlooville

Re: RPi3: WiFi Channel 11 Problem

Fri Mar 25, 2016 11:12 pm

Perhaps the channel is also being used by your neighbours and causing interference? There are wifi analysers available for PCs and phones that can show the congestion on channels.

dchao99
Posts: 45
Joined: Fri Jan 15, 2016 9:26 pm

Re: RPi3: WiFi Channel 11 Problem

Sat Mar 26, 2016 12:37 am

asandford wrote:Perhaps the channel is also being used by your neighbours and causing interference? There are wifi analysers available for PCs and phones that can show the congestion on channels.
I had no problem using my old Edimax WiFi dongle on channel 11 (using Pi-2). Also, all my computers can run on channel 11 with no problem at all.
Plus 802.11g/n uses OFDM, it should be able to cope with channel collision with my neighbors networks, unless the interference is very bad. When channel selection on my router is set to auto, channel 11 is the recommended channel, as my router thinks channel 11 has the least interference in my house

asandford
Posts: 1997
Joined: Mon Dec 31, 2012 12:54 pm
Location: Waterlooville

Re: RPi3: WiFi Channel 11 Problem

Sat Mar 26, 2016 12:52 am

dchao99 wrote: I had no problem using my old Edimax WiFi dongle on channel 11 (using Pi-2). Also, all my computers can run on channel 11 with no problem at all.
Plus 802.11g/n uses OFDM, it should be able to cope with channel collision with my neighbors networks, unless the interference is very bad. When channel selection on my router is set to auto, channel 11 is the recommended channel, as my router thinks channel 11 has the least interference in my house
You didn't mention any of that in your post.

zealousd
Posts: 93
Joined: Sun Mar 20, 2016 10:57 am

Re: RPi3: WiFi Channel 11 Problem

Sat Mar 26, 2016 1:56 am

Raspberry Pi 3
Ubuntu Mate
Web Server

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