No abstract

Abstract-Effective emergency and natural disaster management depend on the efficient mission-critical voice and data communication between first responders and victims. Land Mobile Radio System (LMRS) is a legacy narrowband technology used for critical voice communications with limited use for data applications. Recently Long Term Evolution (LTE) emerged as a broadband communication technology that has a potential to transform the capabilities of public safety technologies by providing broadband, ubiquitous, and mission-critical voice and data support. For example, in the United States, FirstNet is building a nationwide coast-to-coast public safety network based of LTE broadband technology. This paper presents a comparative survey of legacy and the LTE-based public safety networks, and discusses the LMRS-LTE convergence as well as mission-critical push-to-talk over LTE. A simulation study of LMRS and LTE band class 14 technologies is provided using the NS-3 open source tool. An experimental study of APCO-25 and LTE band class 14 is also conducted using software-defined radio, to enhance the understanding of the public safety systems. Finally, emerging technologies that may have strong potential for use in public safety networks are reviewed.Index Terms-APCO-25, FirstNet, heterogeneous networks, LMRS-LTE convergence, mission-critical push-to-talk, P-25, public safety communications, software-defined radio (SDR), TETRA, unmanned aerial vehicle (UAV), 3GPP, 5G.

No abstract

Ensuring ubiquitous mission-critical public safety communications (PSC) to all the first responders in the public safety network (PSN) is crucial at an emergency site. Recently, the use of unmanned aerial vehicles (UAVs) has received extensive interest for PSC to fill the coverage holes and establish reliable connectivity. The UAVs can be deployed as unmanned aerial base stations (UABSs) as part of a heterogeneous network (HetNet) PSC infrastructure. In this article, we design a PSC LTE-Advanced HetNet for different path loss models and deployment mechanism for UABSs. We enhance the system-wide spectral efficiency (SE) of this PSC HetNet by apply cell range expansion (CRE) to UABSs and mitigating the inter-cell interference arising in the HetNet by applying 3GPP Release-10 enhanced intercell interference coordination (eICIC) and 3GPP Release-11 further-enhanced inter-cell interference coordination (FeICIC). Through Monte-Carlo simulations, we compare the system-wide 5th percentile SE when UABSs are deployed on a hexagonal grid and when their locations are optimized using a genetic algorithm, while also jointly optimizing the CRE and the intercell interference coordination parameters. Our results show that at optimized UABS locations, reduced power subframes (FeICIC) defined in 3GPP Release-11 can provide considerably better 5th percentile SE than the 3GPP Release-10 with almost blank subframes (eICIC).