If you're willing to take up a suitcase worth of room, you can use standard analog ICs and RF building blocks to take a quite normal DAC and upconvert it to RF, and downconvert the receive chain likewise to a very common ADC. The standard wifi channel width of 20MHz should place it within reach of quite a few off-the-shelf chips.
That approach should be able to do the whole thing with no NDAs or whatever; it would be a fine capstone project for someone chasing an EE/RF degree...
I think it would be cool if 100% of the digital logic was open source, and 100% of the analog was at least well-understood, and commoditized. Kind of like how you don't need an open source op-amp, they're well understood and commoditized (for most applications).
Does it really take up a suitcase worth of electronics to do what the transceiver IC's are doing?
The HackRF One can do 1MHz-6GHz, but also indicates "8-Bit I and 8-Bit Q".
On the one hand I'm like, it's basically just dumping wideband spectrum into the air, right?
On the other hand the OpenOFDM reference talks quite a bit about much larger I/Q values, so maybe "8-bit quadrature samples" is exactly why nobody uses it for Wi-Fi. :(
8bit I/Q definitely can be used for WiFi. I used HACKRF to send and capture Wifi packet without an issue (offline, use Matlab to process the captured I/Q samples).
Low resolution I/Q (8bit) will impact the RX sensitivity and TX EVM, but it won't be a factor that will totally fail the WiFi implementation.
The HackRF One uses a series of up/down converters, plus a MAX2837 for tuning, and a MAX5864 for the actual ADC/DAC. It goes 22 MSPS, so it can theoretically look at any ~20 mhz section of the 1 MHz - 6 GHz tuning range.
WiFi channels are generally 20, 40 or 80 MHz, so the latter two are not possible given the hardware, and the smallest (20 MHz) would be right at the limit of the hardware. Additionally, there may be other complications (tx/rx switching speed, tuning speed (I'm not sure if wifi would need to do frequency hopping, and if the bandwidth is sufficient to mitigate that need), etc...)
And then someone would have to actually implement it.
Sadly from my research of cheap and hobbyist SDRs, you generally aren't gonna get high bandwidth. I have a limesdr-usb sitting around which supports ~60mhz bandwidth iirc which wasn't good enough for a specific application I looked at which required a channel width up-to 192mhz. Although I'm also an absolute RF noob, do I may have misinterpreted something.
tx/rx switching speed is easy enough by just having two units. Use separate antennae so one doesn't fry the other.
Also just for safety's sake, twiddle your receive preamp gain down before transmitting. That can be done very quickly. Could probably tie a line between the two and have the CPLD do that, actually.
If you're willing to take up a suitcase worth of room, you can use standard analog ICs and RF building blocks to take a quite normal DAC and upconvert it to RF, and downconvert the receive chain likewise to a very common ADC. The standard wifi channel width of 20MHz should place it within reach of quite a few off-the-shelf chips.
That approach should be able to do the whole thing with no NDAs or whatever; it would be a fine capstone project for someone chasing an EE/RF degree...