The adoption of smartphones has had as a corollary the use of services
that require streaming, such as video streaming, which is a constraint
for the 4G mobile network. The integration of the network of Wi-Fi
hotspots deployed by the operators adds capacity to the 4G mobile
network.
The use of Wi-Fi technology in carrier networks is the result of
developments coordinated by the IEEE, WFA and WBA standardization
bodies. For its part, the 3GPP standardization body has been working to
integrate Wi-Fi technology into the 4G mobile network.
The first part of this book presents the characteristics of the Wi-Fi
radio interface. The different IEEE 802.11b / g / n / ac physical layers
characterize the implementation in the 2.4 GHz ISM frequency bands and
U- NII at 5 GHz. The MAC layer defines a number of media access
procedures such as scanning, associating, or transferring data.
The second part of this book deals with the architecture of the 4G
network based on the Wi-Fi interface. This architecture defines several
models corresponding, on the one hand, to Wi-Fi access controlled or
not, On the other hand, to a handover controlled by the network or by
the mobile. The integration of Wi-Fi technology resulted in a
redefinition of attachment and session set-up procedures.
Smartphones have the ability to activate simultaneously the two radio
interfaces, LTE and Wi-Fi, which allows to direct certain services to
one and / or the other of the interfaces. The ANDSF and HotSpot 2.0
functions provide the mobile with rules for network selection and
traffic control to determine which traffic is to be routed to what type
of interface.
