  Driven by increasing demands on connectivity to improve safety, situational
awareness and operational effectiveness for first responders, more and more
public safety agencies are realizing the needs of modernization of their
existing non-3GPP networks. 3GPP based cellular networks offers the unique
opportunity of providing fast, reliable, and prioritized communications for
first responders in a shared network. In this article, we give an overview of
service requirements on public safety mission critical communications. We
identify key technical challenges and explain how 5G NR features are being
evolved to meet the emerging safety critical requirements, including enabling
connectivity everywhere, supporting efficient group communications,
prioritizing mission critical traffic, and providing accurate positioning for
first responders.
