Public Safety Scenarios Research Articles

5G NR Sidelink Multi-Hop Transmission in Public Safety and Factory Automation Scenarios

The deployment of D2D communications (also known as ProSe or sidelink transmissions) in cellular networks benefits from proximity, multi-hop, and spatial reuse gains. In this article, we first describe the main advancements of NR sidelink compared to LTE-A sidelink. Then, we run a simulation campaign to test D2D-based ProSe for public safety and factory automation scenarios with their mission-critical requirements and ultra-reliable low-latency communications, respectively. A preliminary study on NR sidelink usage for both considered use cases is performed, aiming to identify the main advantages and disadvantages thereof. Finally, important future directions for the NR sidelink development from a standardization perspective are highlighted.

MIMO Relaying UAVs Operating in Public Safety Scenarios

Methods to implement communication in natural and humanmade disasters have been widely discussed in the scientific community. Scientists believe that unmanned aerial vehicles (UAVs) relays will play a critical role in 5G public safety communications (PSC) due to their technical superiority. They have several significant advantages: a high degree of mobility, flexibility, exceptional line of sight, and real-time adaptative planning. For instance, cell edge coverage could be extended using relay UAVs. This paper summarizes the sidelink evolution in the 3GPP standardization associated with the usage of the device to device (D2D) techniques that use long term evolution (LTE) communication systems, potential extensions for 5G, and a study on the impact of circular mobility on relay UAVs using the software network simulator 3 (NS3). In this simulation, the transmitted packet percentage was evaluated where the speed of the UAV for users was changed. This paper also examines the multi-input multi-output (MIMO) communication applied to drones and proposes a new trajectory to assist users experiencing unfortunate circumstances. The overall communication is highly dependent on the drone speed and the use of MIMO and suitable antennas may influence overall transmission between users and the UAVs relay. When the UAVs relaying speed was configured at 108 km/h the total transmission rate was reduced to 55% in the group with 6 users allocated to each drone.

Surveying pervasive public safety communication technologies in the context of terrorist attacks

Existing public safety networks (PSNs) are not designed to cope with disasters such as terrorist attacks, consequently leading to long delays and intolerable response times. First responders’ life threats when accessing the attacked zone are more severe in comparison to other disasters and the accuracy of basic information such as the number of terrorists, the number of trapped people, their locations and identity, etc., is vital to the reduction of the response time. Recent technologies for PSNs are designed to manage natural disaster scenarios; these are not best suited for situations like terrorist attacks because a proper communication infrastructure is required for operating most of the classical PSNs. This serious concern makes it highly desirable to develop reliable and adaptive pervasive public safety communication technologies to counter such a kind of emergency situation. Device-to-device (D2D) communication can be a vital paradigm to design PSNs that are fit for dealing with terrorist attacks thanks to long-term evolution (LTE)-sidelink, which could allow the devices that people carry with themselves in the attacked zone to communicate directly. To our best knowledge, this is the first survey paper on public safety communication in the context of terrorist attacks. We discuss PSN scenarios, architectures, 3rd generation partnership project (3GPP) standards, and recent or ongoing related projects. We briefly describe a system architecture for disseminating the critical information, and we provide an extensive literature review of the technologies that could have a significant impact in public safety scenarios especially in terrorist attacks, such as beamforming and localization for unmanned aerial vehicles (UAVs), LTE sidelink for both centralized (base-station assisted) and decentralized (without base-station) architectures, multi-hop D2D routing for PSN, and jamming and anti-jamming in mobile networks. Furthermore, we also cover the channel models available in the literature to evaluate the performance of D2D communication in different contexts. Finally, we discuss the open challenges when applying these technologies for PSN.

Drone-Initiated D2D-Aided Multihop Multicast Networks for Emergency Information Dissemination

Due to their fast and flexible deployment, drones can support terrestrial networks for rapid information dissemination by broadcasting emergency messages to ground devices in public safety scenarios (e.g., bushfire and flood). In this paper, we consider a drone-initiated device-to-device-aided (D2D-aided) multihop multicast network where a drone is deployed to broadcast an emergency alert message to all terrestrial D2D users at the first time slot. After that, the D2D users that have successfully received the message become the active transmitters and multicast the message through multihop for the next time slots. Using stochastic geometry, we propose a general analytical framework to compute the link coverage probability, the mean local delay for a D2D user and the network coverage probability. The Monte Carlo simulation results confirm the accuracy of the proposed framework. Our results reveal the impacts of the different system parameters (i.e., height and transmit power of the drone and density and sensitivity radius of the D2D users) on the link performance and the network performance. It is found that a higher drone altitude provides better link and network coverage probabilities and lower mean local delay. The results show that under practical setups, the cell edge user located 2 km from the ground projection of the drone has a link coverage probability around 90% after 5 time slots and a mean local delay of 2.32 time slots with a drone height as low as 200 m.

An Effective and Efficient Dynamic eMBMS Multicast Grouping Scheduling Algorithm in MBSFNs for Public Safety Scenarios.

The LTE (Long-Term Evolution) eMBMS (evolved Multimedia Broadcast Multicast Service) technology employed in MBSFNs (Multicast Broadcast Single Frequency Networks) has been shown to be capable of considerably increasing the capacity of serving public safety users under group communication scenarios. However, due to its own limitations, a more fine-tuned scheduling approach is needed in order to fully utilize the strengths of eMBMS multicast. In this work, we first identify and analyze several overlooked challenges for scheduling multicast traffic in MBSFNs. Then we develop an effective and efficient dynamic scheduling algorithm for eMBMS multicast in time and frequency varying channel. The proposed algorithm leverages the advantages of both multicast and unicast schemes via user grouping; and through extensive simulations, is shown to be capable of significantly enhancing the mission critical performances under both best effort and guaranteed bit rate delivery models. We also show the resiliency of our proposed algorithm by applying it onto various network and user deployment scenarios. Our consistent results further prove that LTE eMBMS in MBSFN is a key solution in overcoming limitations in near future public safety networks.

State-Based Uplink-Scheduling Scheme for Reducing Control Plane Latency of MCPTT Services

This paper addresses an uplink (UL) scheduling issue that arises in the midst of the recent trend in applying the commercial long term evolution (LTE) technology to public safety. Mission critical push-to-talk (MCPTT), which specifies a group communication service over LTE in public-safety scenarios, needs to satisfy the requirements of extremely short latency for its control procedures. We herein propose a practical UL-scheduling scheme, which can be feasible in the LTE system to shorten the time for the initial UL transmissions. Through the empirical assessment conducted on our LTE-based MCPTT testbed, the proposed scheme is validated to reduce the control plane latency with the little increment of implementation complexity.

Survey of Public Safety Communications: User-Side and Network-Side Solutions and Future Directions

To prevent economic losses, maintain social order, and protect the well-being of the populace during public safety and crisis recovery scenarios, such as man-made and natural disasters, the efficient and effective delivery of time-critical information to first responders and victims plays a key role. Nonetheless, too often, the communication infrastructures that enable time-critical information delivery become dysfunctional, due to traffic overloads or physical damage. Thus, the user-side solution [e.g., device-to-device (D2D) communications] and the network-side solution [e.g., dynamic wireless networks (DWNs)] are essential communication techniques that can enhance or restore communication for responders and victims in the harsh environment associated with public safety scenes. While D2D has been widely studied and investigated in legacy/commercial communication networks, as well as DWN, little work has been done toward adapting D2D and DWN from a public safety perspective. In this survey, we first design a layered structure, consisting of the public safety service layer, time-critical information delivery layer, and physical object layer, from which to consider the public safety system and its key components. We then extensively review research efforts on both D2D and DWN as complimentary user-side and network-side communication techniques toward effective public safety communications. Particularly, we investigate the approaches and standardization progress of D2D and DWN for public safety communications. Finally, we provide insights into challenges and potential solutions regarding D2D, DWN, security and resilience, and performance evaluation of public safety communication, as well as the integration of state-of-the-art communication and computing technologies to further improve time-critical information delivery in various public safety scenarios.

SoftPSN: Software‐Defined Resource Slicing for Low‐Latency Reliable Public Safety Networks

Achieving the low‐latency constraints of public safety applications during disaster could be life‐saving. In the context of public safety scenarios, in this paper, we propose an efficient radio resource slicing algorithm that enables first responders to deliver their life‐saving activities effectively. We used the tool of stochastic geometry to model the base station distribution before and after a disaster. In addition, under this umbrella, we also proposed an example of public safety scenario, ultrareliable low‐latency file sharing, via in‐band device‐to‐device (D2D) communication. The example scenario is implemented in NS‐3. The simulation results show that radio resource slicing and prioritization of first responders resources can ensure ultrareliable low‐latency communication (URLLC) in emergency scenarios.

On the outage analysis of a D2D network with uniform node distribution in a circular region

This paper studies the coverage probability of a device-to-device (D2D) link between a pair of nodes uniformly distributed in a circular region of arbitrary radius, thereby modeling the D2D network operation for a public safety scenario. The expression for the cumulative distribution function (CDF) of the signal-to-interference ratio (SIR) at the destination is derived, where the transmissions are affected by multipath fading, path loss and interference. The analysis involves finding the ratio distribution of two random variables, representing the desired signal and the intra-region interference, respectively. The expression for CDF helps in ascertaining the outage probability at the destination. Hence, given a desired outage probability, a limit on the number of simultaneously active D2D links in a circular region can be determined, thereby allowing interference avoidance. Numerical simulations are conducted to validate the theoretical model. The Kolmogorov–Smirnov (K–S) test is applied to further characterize the matching between simulation and analytical model. Moreover, the results also help in identifying the minimum transmit power that ensures the desired quality-of-service (QoS), providing efficient transmission in energy constrained environments.

Cooperative energy efficient D2D clustering in LTE-A with enhanced QoS

Device-to-device (D2D) communications in the long term evolution (LTE) Advanced (LTE-A) cellular system are investigated. The objective is to form collaborative D2D groups for transmitting/receiving data in the uplink (UL) and downlink (DL) in an energy efficient manner. The energy minimization problem using multihop D2D is formulated as a binary integer linear program. A low complexity suboptimal solution method is proposed, and shown to lead to good performance, especially in the low complexity 1-hop D2D scenario. The investigated framework is applicable to both public safety (PS) and non-PS scenarios. In addition to significant energy savings, the proposed method is shown to lead to reduced delays and enhanced quality of service (QoS), especially when real-time video transmission is considered.

M3-Cast: A Novel Multicast Scheme in Multi-Channel and Multi-Rate WiFi Direct Networks for Public Safety

WiFi direct (WD) network is of significant interest during public safety scenarios due to its easy, quick, and efficient implementation. WD provides device to device communication using the MAC and PHY layers specifications of 802.11 standards, which facilitate multiple communications channels and a number of transmission rates to cope with the requirements and challenges of emerging applications in public safety and disaster management. Although they achieve substantial benefits in terms of high throughput, it creates a performance anomaly problem, wherein the selection of a particular communication channel and transmission rate can significantly affect the performance of a wireless communication system. This paper investigates the problem of selecting the most favorable channel and rate for a multicast communication system in the context of public safety using a WD 802.11 network. To this end, M3-Cast protocol is proposed, which refers to a novel multi-rate multi-channel multicast scheme. M3-Cast not only chooses the most favorable communication channel and transmission rate, but also considers the implementation details of the underlying WD technology, thereby optimizing the overall system performance. M3-Cast is formulated analytically and evaluated by a complete system level simulation. The detailed results and the analysis considers a number of performance metrics, such as bit error rate, multicast capacity, and system throughput under different multiple input multiple output configurations, channel bandwidths, and various network radii. Consequently, the simulation and analytical results show that M3-Cast protocol outperforms the standard multicast protocol of WD by almost twofold in terms of system throughput.

Public safety users’ priority‐based energy and time‐efficient device discovery scheme with contention resolution for ProSe in third generation partnership project long‐term evolution‐advanced systems

A device-to-device (D2D) discovery scheme is key enabler for proximity-based services in third generation partnership project long-term evolution-advanced systems for public safety (PS) and general LTE scenarios. The deployment of D2D networks results in severe co-channel interference between conventional cellular users and D2D users, and faces proximity interference management challenges because of the co-existence of multiple D2D users. We propose a time and energy-efficient contention-resolving device discovery resource allocation (TEECR-DDRA) scheme that has the capability to enhance the success ratio for discovery of D2D users by reducing collisions among users. Moreover, the proposed TEECR-DDRA scheme has the ability to prioritise PS users to meet their QoS and latency requirements. Furthermore, multi-channel slotted ALOHA with energy sensing can be used to increase the probability of successful discovery of non-PS users. This ability helps to reduce the discovery time of PS users under disaster scenarios, and also reduces the energy consumption of non-PS users by minimising the number of beacon retransmissions. System-level simulations show that the proposed TEECR-DDRA scheme performs remarkably well under D2D network. Compared with the conventional random access scheme, the proposed scheme almost doubles the discovery range and significantly improves the success ratio for discovery of D2D users.

Aerial base stations with opportunistic links for next generation emergency communications

Rapidly deployable and reliable mission-critical communication networks are fundamental requirements to guarantee the successful operations of public safety officers during disaster recovery and crisis management preparedness. The ABSOLUTE project focused on designing, prototyping, and demonstrating a high-capacity IP mobile data network with low latency and large coverage suitable for many forms of multimedia delivery including public safety scenarios. The ABSOLUTE project combines aerial, terrestrial, and satellites communication networks for providing a robust standalone system able to deliver resilience communication systems. This article focuses on describing the main outcomes of the ABSOLUTE project in terms of network and system architecture, regulations, and implementation of aerial base stations, portable land mobile units, satellite backhauling, S-MIM satellite messaging, and multimode user equipments.

Extending TETRA with wireless sensor networks

The Terrestrial Trunked Radio TETRA system is an open standard developed by ETSI and designed to support mobile radio communications in a number of market segments, among which public safety is by far the largest one. In this paper, we present the activities to the 'TETRis - TETRA Innovative Open Source Services' project to integrate wireless sensor networks technology with TETRA, in order to support real-time feedback in two application contexts relevant in public safety scenarios: structural health monitoring and air quality monitoring. The WSN deployed in our testbed is based on the MagoNode platform, a new mote featuring an RF front-end capable to enhance the radio performance. The results of the experimental activity confirm that WSNs can be effectively used to support the management of critical situations in the considered scenarios and that the MagoNode platform well meet the requirements provided by experts on structural health monitoring.

A Software-Defined Device-to-Device Communication Architecture for Public Safety Applications in 5G Networks

The device-to-device (D2D) communication paradigm in 5G networks provides an effective infrastructure to enable different smart city applications such as public safety. In future smart cities, dense deployment of wireless sensor networks (WSNs) can be integrated with 5G networks using D2D communication. D2D communication enables direct communication between nearby user equipments (UEs) using cellular or ad hoc links, thereby improving the spectrum utilization, system throughput, and energy efficiency of the network. In this paper, we propose a hierarchal D2D communication architecture where a centralized software-defined network (SDN) controller communicates with the cloud head to reduce the number of requested long-term evolution (LTE) communication links, thereby improving energy consumption. The concept of local and central controller enables our architecture to work in case of infrastructure damage and hotspot traffic situation. The architecture helps to maintain the communication between disaster victims and first responders by installing multi-hop routing path with the support of the SDN controller. In addition, we highlight the robustness and potential of our architecture by presenting a public safety scenario, where a part of the network is offline due to extraordinary events such as disaster or terrorist attacks.

Energy Efficient and Load Balanced Routing for Wireless Multihop Network Applications

Wireless Sensor Networks (WSNs) can benefit from ad hoc networking technology characterized by multihop wireless connectivity and infrastructure less framework. These features make them suitable for next-generation networks to support several applications such M2M applications for smart cities and public safety scenarios. Pivotal design requirements for these scenarios are energy efficiency, since many of these devices will be battery powered placing a fundamental limit on network, and specifically node lifetime. Moreover, the way in which traffic is managed also influences network lifetime, since there is a high probability for some nodes to become overloaded by packet forwarding operations in order to support neighbour data exchange. These issues imply the need for energy efficient and load balanced routing approaches that can manage the network load and not only provide reduced energy consumption on the network but also prolong the network lifetime providing robust and continuous. This work proposes a new energy efficient and traffic balancing routing approach that can provide a weighted and flexible trade-off between energy consumption and load dispersion. Simulation results show that the proposed protocol achieves high energy efficiency, decreases the percentage of failed nodes due to lack of battery power, and extends the lifespan of the network.

BonnSens: A Mesh-based Command and Control Sensing System for Public Safety Scenarios

BonnSens: A Mesh-based Command and Control Sensing System for Public Safety Scenarios

Applying a framework for defining emergency management scenarios

Introduction: Scenarios are used extensively to support emergency management (EM). Virtually every user within the community, from policymakers to first responders, uses scenarios in one guise or another. They provide the context to characterize a dynamic problem space, to support the rehearsal of response options, and to facilitate the evaluation of new technology. With such far-reaching implications, there needs to be a means to guide scenario selection.Objective: The Canadian Centre for Security Science sponsored the development of a framework to characterize scenarios and to assist in evaluating EM capabilities, explicitly in the area of chemical, biological, radiological, and nuclear response. The framework also complements capability-based planning and provides a means to share scenarios.Methodology: The Public Safety and Security Planning Scenario Framework assists the EM community, which ranges from the national to the community level, by selecting scenarios based on user perspectives and objectives. In developing the framework, three challenges were addressed: a taxonomy was required to frame and define what constitutes a scenario; parameters were needed to describe and characterize scenarios; and structure was called for to assist in ordering the collection and comparison of representative scenarios.The first challenge involved reviewing existing literature to define the term “scenario.” Typically, scenarios are used to consider near-term threats, to capture planning assumptions, and to provide the perspective necessary to assess concepts and capabilities. The framework proposes a set of criteria or dimensions (eg, risks, triggers, and time horizons) that can be used to characterize scenarios. To test the framework, a representative set of scenarios was cataloged using these dimensions. Analysis of the resulting set was instructive in revealing the differences in planning scenarios across the chemical, biological, radiological/nuclear, and explosive communities. As the framework matures, it is hoped that it will promote information reuse and provide a valuable forum for capturing best practices and developing standards, enhancing efficiency and effectiveness improvements both locally and nationally.