ETSI - TS 122 468
LTE; Group Communication System Enablers for LTE (GCSE_LTE)
|Publication Date:||1 October 2014|
The present document collects the requirements as relevant to improve the EPC and E-UTRAN for system enablers to the 3GPP system to support Group Communication over LTE for Public Safety and Critical Communication.
The US requirements as specified in NPSTC (Mission Critical Voice Requirements) , , , the TETRA + Critical Communications Association (TCCA)  and ITU ,  inputs are taken as starting point.
Other regional requirements may also be reflected in the work. The requirements are worded in a way to easily accommodate future requirements from other regions or stakeholders.