To ease congestion caused by increased tablet and smart phone traffic, carriers often
supplement mobile services in densely populated areas with Wi-Fi in airports, train
stations, and cafés where mobility is not required. In addition, Wi-Fi hotspots relieve
backhaul congestion by transmitting traffic over broadband links rather than on the
mobile network.
Wi-Fi equipment is less costly than base stations in mobile networks and spectrum
is free. While cellular service excels at covering large areas, Wi-Fi service does
extremely well at providing coverage inside buildings where it is relatively inexpensive
to add access points.
This trend has been made possible by the advent of handsets with chips that support
both Wi-Fi and mobile air interfaces. These interfaces are now tightly integrated
and have the capability to automatically hand traffic off between cell sites and Wi-Fi
networks. They additionally support both voice and data. However, using voice on
Wi-Fi networks drains batteries more quickly than on mobile networks.
The downside of operating large numbers of small cell sites and hotspots is maintenance.
Large carriers can have 50,000 of these sites to manage. Many mobile operators
outsource management of their picocell sites, small cellular base stations, and
hotspots to other firms. Picocells are another option for coverage inside buildings. For
more information about picocells,

