Definitely try restarting your router. Just because other devices aren't having a problem connecting to your home network doesn't mean there's no problem with your Tab S2's connectivity. Networking between devices just isn't that simple, it involves numerous and constant interactions between your device and your router no matter if you yourself is even doing anything on your device, and that all involves individual exchanges between each device and your router.
You referred to restarting your Tab S2 but try restarting both your Tab S2 and your router. Then if you're still having problems you've eliminated the issue of some one-off glitch and you know there's a more definitive problem.
-- Have you tried using your Tab S2 using a different WiFi network like at a friend or family?
If it drops online connectivity elsewhere too than that indicates the problem is more likely to be with your Tab S2. You might want to try going into your Settings menu and find a 'Network settings reset' option. This will wipe all network-related settings and return them to their clean defaults, so keep in mind things like saved WiFi and Bluetooth pairings will get deleted.
But if it stays connected properly elsewhere, this indicates your problem could be tied to something with your home network setup. Do you have an ISP-supplied modem/router unit or do you have your own router? If a modem/router who is your ISP? If your own router, what model? Also, is your Tab S2 connecting to your home WiFi using a 2.4GHz or 5GHz band network?