Customizable WiFi AP bandwidth (e.g. 1 MHz) possible?

Is it possible to configure an arbitrary non-standard operation bandwidth for a WiFi AP (e.g. 1 MHz) with OpenWRT?
If so, what modification are needed to let users associate and exchange traffic with the AP ?


No, but 5 MHz and 10 MHz are possible on some chipsets. On Mediatek chipsets, you have to modify the ROM to support it, so likely no. Search for confidential datasheets if you're interested. On Atheros/Qualcomm ath9k chipsets some chips support it (at least all Ubiquiti AirMax XW and XM devices). Look at the AREDN firmware for that.

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That's that was my guess.
Does anyone know of SDR-based WiFi implementations allowing this degree of freedom in picking the bandwidth?


On transmit, or just receive? What's your budget?

Even low-order QAM modulation on top of ODFM at tens or hundreds of mbit/s requires quite a bit of processing power.

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Ideally i'd like to have a WiFi link AP and STA where I can deliberately change the bandwidth of the communication (e.g. set it to 1 MHz).

If not available on commercial hardware, I am open to SDR-based WiFi implementations, given that they employ CSMA/CA based transmissions.

This might off-topic here, but any help is greatly appreciated.

So, what's wrong with the hardware that was suggested above?

They're known to accept 5 and 10 MHz bandwidths.

See: - especially the chanbw portion for valid settings. To be clear, 1 MHz is not a valid, nor logical, bandwidth setting (do the math to find out why).

So you want to purchase 2 SDR radios, just for WiFi? You'll definitely need two - if you plan to configure non-standard bandwidth and modulation schemes.

That sounds expensive.

Another thing is that in many countries other channel widths than 20 or 40 MHz are illegal on WLAN frequencies. If you want to experiment with those channel widths, you should become a HAM and use amateur radio frequencies.