Efficiency Analysis and Improvement of SIP-based Push-to-Talk over Cellular

“Push-to-talk over Cellular” (PoC) which is wireless technology and is used on mobile telecom network can enable cell phones capability of one-to-many communications, as the walkie-talkie. PoC is a new potential communication service using cellular network without the defect of walkie-talkie limited communication distance. In this paper, the performance of today's PoC is evaluated, and the results show that senders may not be able to start talking until about six seconds after pushing the talk key. A long waiting time for users will negatively affect the use of PoC. Therefore, a performance improving scheme is presented in our work to reduce waiting time and number of messages for PoC users.