Push-to-talk over cellular is a set of devices and communication services. Also, it is a set of processes that include two-way communication technology with help of wireless devices. It majorly includes push-to-talk voice service for smart phone communications and provides one-to-many and one-to-one voice communication services over a cellular network. The half-duplex Voice-over-IP (VoIP) technology over mobile networks is proliferating the push-to-talk over cellular services for using cellular access resources at its best. In addition, reliable communications services with high quality audio support is also expected to drive the push-to-talk over cellular market growth in the coming years.