Push-to-Talk over LTE Modeling and Performance Evaluation

Abstract

Public Safety organizations play a vital role in disaster recovery and public protection. First responders rely on their communication systems to perform their mission. Their communication systems are considered mission critical which puts special requirements on their underlying enabling technologies. Nowadays, most of the communication systems used in public safety are narrowband and were mainly developed for voice communication. Push-to-Talk is a multicast (group call) half-duplex type of communication that emergency first responders heavily rely on. When first responders request to speak by pushing the button on their handset, during emergencies, they must be confident that their requests will go through and not blocked. LTE technology has been chosen in many countries, including the US, to be the platform for the next generation public safety communication systems. LTE is a broadband wireless communication technology that public safety communication may benefit from the high data rates LTE technology offers. This paper proposes an analytical model of Push-to-Talk over LTE networks to study their performance by using queueing theory. The model is validated against a discrete event simulation (SimEvents). The study provides some guidelines to improve the Grade of Service (GOS) of Push-to-Talk over LTE systems.