with usb wireless nic's and openwrt(and linux in general I suppose despite what manufacturers often claim)...
it's best to assume they don't work unless told otherwise...
starting from a point of expecting it work without stating what makes this expectation valid is naive at best...
- what makes you think it will work out of the box
- what research have you done about it and openwrt ( what guide or instructions did you settle on )?
- have you used it in a full distro... / what kernels does the manufacturer claim to support?
- what is the actual specs / revision of your individual adapter...?
in short... I suggest you do a little reading... possibly starting here...
and working your way down from there...