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#1 2014-Oct-31 17:54:10

Stephen
Member
Registered: 2014-Aug-27
Posts: 25

2.4GHz Channel 14 in 802.11 Ref. Design?

Hi,

I need to use channel 14 of 2.4 GHz band in 802.11 reference design for my measurements. The default deign cannot support channel 14. But I think it can be done if I change some part of the default design. Can you show me the changes to the default codes that I need or direct me to the documents on this? Thanks.

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#2 2014-Nov-01 13:29:52

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

Re: 2.4GHz Channel 14 in 802.11 Ref. Design?

In Python the default supported channels are defined by the variable 'wlan_channel' in wlan_exp/util.py.

In C the default supported channels are set by the wlan_lib_channel_verify() method.

Setting the node's current channel from Python requires both the wlan_exp and C implementations agree on which channels are implemented.

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#3 2014-Nov-01 14:53:14

Stephen
Member
Registered: 2014-Aug-27
Posts: 25

Re: 2.4GHz Channel 14 in 802.11 Ref. Design?

So in the C code, I only need to add case 14: in the wlan_lib_channel_verify() method and then regenerate new AP and STA bitstream file

In the Python codes, I only need to add 'index' :  14, 'channel' :  14, 'freq': 2484, 'desc' : '2.4 GHz Band' in the wlan_channel list.

Then I can use the channel 14, right? And Does this channel also have 20MHz and 64 subcarriers?

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#4 2014-Nov-02 18:49:04

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

Re: 2.4GHz Channel 14 in 802.11 Ref. Design?

I believe those are the only required changes.

The set_channel() method only tunes the radio to a different center frequency. It does not affect the bandwidth or subcarrier mapping the PHY uses at that frequency.

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#5 2014-Nov-02 19:26:20

Stephen
Member
Registered: 2014-Aug-27
Posts: 25

Re: 2.4GHz Channel 14 in 802.11 Ref. Design?

I see. And those changes can work. I have successfully used channel 14. Thanks.

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#6 2016-Aug-15 11:48:45

Rebecca
Member
Registered: 2016-Aug-15
Posts: 1

Re: 2.4GHz Channel 14 in 802.11 Ref. Design?

Has the process changed in the newest release (1.5.2)? I've made changes in wlan_exp\util.py, wlan_mac_low.c, wlan_mac_common.c, and wlan_mac_scan.c with no luck so far.

Last edited by Rebecca (2016-Aug-15 11:51:11)

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#7 2016-Aug-15 15:56:41

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

Re: 2.4GHz Channel 14 in 802.11 Ref. Design?

You'll have to be more specific than "no luck" about what you changed and what you observed. Ultimately the radio is tuned by the wlan_mac_low_set_radio_channel() function in the lower MAC code in wlan_mac_low.c. This function calls the radio_controller driver function radio_controller_setCenterFrequency() to configure the MAX2829 PLL. You can add a xil_printf() in wlan_mac_low_set_radio_channel() to verify it is calling radio_controller_setCenterFrequency() with your desired channel, then debug from there if not.

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