It depends on the construction of your house, but as the Router and the Smart Device are on separate floors, I guess this will not work very well.
Most Smart TVs don't have the best WiFi built-in adapters, so the stability and the range aren't optimal.
My best guess is to place the router closer or extend your network with an extra access point (Add-on range extender). But before you do, it is best to try the quality of the WiFi adapter of your smart TV by somehow putting it closer to the router before investing in range extenders, etc. My older TV has such a lousy WiFi adapter I needed to connect it to an ethernet cable to function correctly.