Group communication over LTE: a radio access perspective

Long Term Evolution, which has its roots in commercial mobile communications, has recently become an influential solution to future public safety communications. To verify the feasibility of LTE for public safety, it is essential to investigate whether an LTE system optimized for one-to-one communications is capable of providing group communication, which is one of the most important service concepts in public safety. In general, a number of first responders for public safety need to form a group for communicating with each other or sharing common data for collaboration on their mission. In this article, we analyze how the current LTE system can support group communication from the aspect of radio access. Based on the requirements for group communication, we validate whether each LTE-enabled radio access method can efficiently support group communication. In addition, we propose a new multicast transmission scheme, called index-coded HARQ. By applying the index coding concept to HARQ operations, we show that the LTE system can provide group communication that is more sophisticated in terms of radio resource efficiency and scalability. We finally evaluate the performance of LTE-enabled group communication using several radio access methods and show how the proposed transmission scheme enhances performance via system-level simulations.