  The fifth-generation (5G) communication systems will enable enhanced mobile
broadband, ultra-reliable low latency, and massive connectivity services. The
broadband and low-latency services are indispensable to public safety (PS)
communication during natural or man-made disasters. Recently, the third
generation partnership project long term evolution (3GPPLTE) has emerged as a
promising candidate to enable broadband PS communications. In this article,
first we present six major PS-LTE enabling services and the current status of
PS-LTE in 3GPP releases. Then, we discuss the spectrum bands allocated for
PS-LTE in major countries by international telecommunication union (ITU).
Finally, we propose a disaster resilient three-layered architecture for PS-LTE
(DR-PSLTE). This architecture consists of a software-defined network (SDN)
layer to provide centralized control, an unmanned air vehicle (UAV) cloudlet
layer to facilitate edge computing or to enable emergency communication link,
and a radio access layer. The proposed architecture is flexible and combines
the benefits of SDNs and edge computing to efficiently meet the delay
requirements of various PS-LTE services. Numerical results verified that under
the proposed DR-PSLTE architecture, delay is reduced by 20% as compared with
the conventional centralized computing architecture.
