I'm currently working on a project on my Rpi 2 model B that requires connection to internet through a cellular network via 3G/4G connection. I found some usb modem dongles and some modules, but they seem to have outdated/limited documentation. Is there any other hardware solutions that can work, specifically for Canada's cellular network? I'm willing to go for a slightly more complicated solution if it that's the only way.
I'm not sure what country you're in so this might not be relevant, but I'd recommend a 4G router like this. That has the benefit of creating a network you can join other devices to so they can interface rather than being exclusive to the PI. But does cost money for the data plan and router (though you can usually get deals) and probably isn't much more than a dongle.
Alternately if you have a 4G plan on your phone, turn it into a WiFi Hotspot and use that for an adhoc network, if you data plan allows it.
i already realized a similiar project. I just used a normal 3G USB Stick intended for a PC(Huawei -dont remember the type) The software I used was sakis3g. After installation and configuration according to the documentation the stick ran without problems. So I would recommend to have a look at sakis3g.