Not sure what you mean exactly but coming from the IoT end there are plenty of options to connect existing platforms to mobile networks (ArduinoGSMShield for ex

Not sure what you mean exactly but coming from the IoT end there are plenty of options to connect existing platforms to mobile networks (ArduinoGSMShield for example). Coming from the smartphone end there are several hackable projects too that enable you to build a smartphone like IoT device. Look at pine64.org for example they basically have all the parts to build a smartphone like device with sensors.