Offloading reduces the amount of data being carried on the cellular bands, freeing bandwidth for other users.
In addition to smart phones, laptops with 3G access capabilities are also seen as a major source of mobile data traffic.
Femtocells use standard cellular radio technologies, thus any mobile device is capable of participating in the data offloading process, though some modification is needed to accommodate the different backhaul connection.
There are already millions of installed Wi-Fi networks mainly in congested areas such as airports, hotels and city centers and the number is growing rapidly.
Wi-Fi offloading is an emerging business domain with multiple companies entering to the market with proprietary solutions.
Besides standardization, research communities have been exploring more open and programmable design in order to fix the deployment dilemma.
Standardization efforts have focused on specifying tightly or loose coupling between the cellular and the Wi-Fi networks, especially in a network-controlled manner.
The approach is called Interworking Wireless LAN (IWLAN)[19] architecture and it is a solution to transfer IP data between a mobile device and operator's core network through a Wi-Fi access.
Studies show that significant amount of data can be offloaded in this manner to Wi-Fi networks even when users are mobile.[20][21][timeframe?]
The purpose of the ANDSF is to assist user devices to discover access networks in their vicinity and to provide rules (policies) to prioritize and manage connections to all networks.[timeframe?]
The ATSSS service leverages the Multipath TCP protocol to enable 5G devices to simultaneously utilize different access networks.
Experience with the utilisation of Multipath TCP on iPhones has shown that the ability to simultanesouly use Wi-Fi and cellular was key to provide support seamless handovers.
Such functionality can be found from most modern operating systems (for example from all Windows versions beginning from XP SP3, Ubuntu, Nokia N900, Android and Apple iPhone).
These include performing DNS requests for known names over the newly activated network interfaces, sending queries to specific servers, ...
As of January 2020, Multipath TCP is natively supported on iPhones, but less frequently used on Android smartphones except in South Korea.
If the quality drops below a given threshold, Wi-Fi Assist may decide to move established Multipath TCP connections to another interface.