WiFi with SDR at 470 MHz

[sluge]

Hello,
I need to implement WiFi 802.11 a/b/g/n/ac protocol with SDR at 470MHz.
- Is it possible to implement WiFi at this frequency?
- Is any existing implementations about it?

[N4TKO]

470Mhz is in the TV band. in the US, it's also been designated as "whitespace", which means it can be used for secondary purposes. one of those is for data. but there are some rules for data use.... 1) no more than 4 watts ERP, 2) must use the channel width of 6Mhz (which means wifi devices which use 20Mhz or wider channels are not allowed), c) the devices used must be "cognitive" radios, which means if the channel is in use, it cannot transmit, but must find another channel to operate on (and must also check an online geographic database of other devices in the area using those frequencies). there are some areas that use parts of this spectrum space for public safety services, and you have to avoid interfering with these as well. that means your cognitive radio has to sample the whole 6Mhz width of the channel before deciding to use it. that's quite a bit more "smarts" than what's inside wifi routers (obviously, because wifi routers interfere with each other constantly without the ability to "hop" to other channels). there have been a few companies exploring the idea of using whitespace for wireless internet distribution (google and microsoft lobbied the FCC to get whitespace in the first place, with that very purpose in mind) but very little in the way of actual hardware and testing has been accomplished since 2008. i think the real "killer" is the "cognitive" part of the rules, which makes it difficult to be able to stream data continuously and smoothly (and the fact that the required geographic database still doesn't exist).

it would be nice to be able to connect a transverter (a device which shifts your rx and tx frequencies) to a wifi box and plop it down wherever in the spectrum you want to, but different parts of the spectrum have different users and different sets of rules, and you have to check those things out first. in the US the FCC can at the very least tell you to stop using equipment that interferes with other services, or they can take your equipment, or they can fine you $10,000