It's very likely that the S4 is only providing "ad hoc" and not "infrastructure" mode WiFi networking. PS3 doesn't support and can't connect to ad hoc mode networks AFAIK. What you can do about it, I don't know sorry.
Infrastructure mode is when you're using a real physical WiFi router.
Ad hoc mode is when WiFi networking is provided by software, often running on a PC or laptop.