Wi-Fi Assist detects a weak Wi-Fi signal and automatically switches a user’s iPhone over to a stronger cellular signal, if available, so that the user doesn’t experience any of the symptoms associated with poor Wi-Fi, such as drop-outs and buffering.
One of the most common scenarios where Wi-Fi Assist will make a big difference is when a user leaves the Wi-Fi network while actively using the Internet.
iPhone can automatically make the switch between a Wi-Fi network and your mobile carrier’s cellular data connection, but the problem is that the iPhone doesn’t always make that switch gracefully.
Most users experience a few moments of connectivity loss as they walk or drive away from their Wi-Fi network. With Wi-Fi Assist, the iPhone will detect that the user’s Wi-Fi network signal is degrading and actively switch over to the cellular connection before the complete loss of the Wi-Fi signal. This, on paper, should produce an experience that is seamless to the user and allows them to continue their active Internet use without interruption.