Experts believe that Voice-over-IP (VoIP), which has reduced calling costs down for residential and business customers, will become equally adopted in the mobile space. According to research by In-Stat, The Business of Mobile VoIP: IP Voice Communications in the Enterprise,  usage is on the rise creating an opportunity for mobile VoIP gateway equipment suppliers as expenditures in mobile VoIP are expected to increase above the $6 billion mark in 2015.