Providing Application Access to Voice Streams: Enhancing PTT Services for Emergency Response

Mission-Critical Push-To-Talk (MCPTT) is an important tool for first responders in the aftermath of a disaster. Most existing MCPTT solutions try to reduce the call-setup delay or mouth-to-ear latency yet fail to optimize the user experience of the whole system. End-system applications primarily manipulate the voice streams through access to the control channel but have limited access to the voice streams. By allowing applications to have access to the voice streams and manage them, we can enable a multitude of features that are critical to first responders. In this paper, we propose Next-Gen MCPTT, a system that aims to improve the efficiency of delivering mission-critical communications. We support concurrent conversations and smooth switching among them, store & replay on demand, a “push-and-talk” capability facilitated by serialization of voice streams at the receiver, and device-to-device (D2D) communication. While MCPTT platforms require the speaker to wait for the floor to become clear before sending a message, Next-Gen MCPTT aims to automatically deliver messages when the channel is available and automatically stores them so the user can switch to other conversations as needed. By creating a system that stores, pauses, and replays messages both online and offline, Next-Gen MCPTT saves precious time for first responders by eliminating the need to constantly wait to acquire the “floor” to speak, repeatedly ask for information that the receiver did not hear clearly. It allows first responders to pay attention to urgent tasks in between and come back and catch up with the conversation later. The cost is a slight increase in the mouth-to-ear latency from allowing applications to get access to the voice streams.