Networks are building more cell towers and improving their existing infrastructure.
Cell sites, which are typically divided into three sectors, are now in many cases being upgraded to six separate radios. That increases their overall capacity.
Sprint Nextel recently announced a $5 billion deal with Ericsson, Alcatel-Lucent and Samsung to modernize its towers -- a plan that the network says will ultimately save the company $10 billion to $11 billion in operating costs over seven years.
About 80% of the cost of a network is in the deployment and maintenance of radio towers, experts say.
NEXT: Backhaul
Last updated December 27 2010: 5:35 PM ET