Regardless of smart home DIY or with professional setup, we need wireless connection and Internet access for smart home devices. For home Wi-Fi system with Internet access, a fiber broadband plan with unlimited access from local Internet service provider (ISP) is preferable.
While away from home, we use smartphone or mobile devices with data plan to monitor and control these smart devices via Internet. While at home, we can monitor and control smart devices directly via wireless connection.
Since home Wi-Fi system with Internet access is becoming common in most households, connecting smart devices to form a smart home system is straightforward.