WARP Project Forums - Wireless Open-Access Research Platform

You are not logged in.

#1 2017-Feb-14 07:48:52

marco
Member
Registered: 2016-Nov-06
Posts: 21

Experiments on different channel frequency in the 2.4 GHz band

Hi,

I work with L-com RE07U-SM antennas, which are designed for the 2.4 GHz band. Unfortunately, this band is so busy. We have a lot of interference inside our lab. Is it possible to set the 802.11 reference design at another center frequency other than the usual channels (for example channel 13 or 14) to avoid interference?

Thanks.

Last edited by marco (2017-Feb-14 07:49:25)

Offline

 

#2 2017-Feb-14 08:22:46

murphpo
Administrator
From: Mango Communications
Registered: 2006-Jul-03
Posts: 5159

Re: Experiments on different channel frequency in the 2.4 GHz band

The 802.11 ref design C uses the wlan_verify_channel() function in wlan_mac_common.c to verify requested channel indexes. Valid channel indexes are then mapped to radio_controller frequency indexes in wlan_mac_low_wlan_chan_to_rc_chan() in wlan_mac_low.c. In Python valid channels are listed in the wlan_channels array in util.py. Please take care when making modifications here to observe any local restrictions on channel use (i.e. channel 14 is not part of the unlicensed 2.4GHz band in most of the world).

Offline

 

#3 2017-Feb-15 09:54:17

marco
Member
Registered: 2016-Nov-06
Posts: 21

Re: Experiments on different channel frequency in the 2.4 GHz band

I added "case 13:" in both functions and I modified python script without error. However, there is no signal at all when I used WiFi analyzer app.

Offline

 

#4 2017-Feb-16 09:14:16

murphpo
Administrator
From: Mango Communications
Registered: 2006-Jul-03
Posts: 5159

Re: Experiments on different channel frequency in the 2.4 GHz band

Is there any UART output from CPU High or Low when you're attempting to tune to a new channel? You can switch the UART between CPU High and Low via the DIP switch.

Offline

 

#5 2017-Feb-17 08:11:11

marco
Member
Registered: 2016-Nov-06
Posts: 21

Re: Experiments on different channel frequency in the 2.4 GHz band

Yes. There is UART output from both CPU High and Low. I tried "log_capture_two_node_two_flow" and I see dramatic drop and oscillation in the transmission throughput.

Last edited by marco (2017-Feb-17 09:28:13)

Offline

 

#6 2017-Feb-17 14:22:06

murphpo
Administrator
From: Mango Communications
Registered: 2006-Jul-03
Posts: 5159

Re: Experiments on different channel frequency in the 2.4 GHz band

Sorry, I don't understand your description of the node's behavior. You should check the UART output to confirm that your new channel definitions are not printing any errors when the radio is tuned.

Offline

 

#7 2017-Feb-20 01:20:03

marco
Member
Registered: 2016-Nov-06
Posts: 21

Re: Experiments on different channel frequency in the 2.4 GHz band

The new channel definitions are not printing any errors. My problem is solved by changing the antennas to work on the 5 GHz band to avoid interference. Thanks anyway for your help.

Offline

 

Board footer