Public Safety Communications Research Articles

Public Safety Communications: Enhancement Through Cognitive Radio and Spectrum Sharing Principles

Wireless communications technologies play an irreplaceable role in emergency and disaster relief situations. It is generally acknowledged that the existing public safety (PS) wireless communications facilities frequently fall short of meeting users' needs in many critical situations. Emergency scenarios usually lead to exceptionally high traffic loads, and the lack of network capacity is one of the major limitations to overcome. In this context, this article first discusses about several dimensions that enable increased capacity in emergency scenarios, and then the attention is placed on the role of spectrum sharing as one of these key dimensions. In this regard, a comprehensive view of possible spectrum-sharing models for emergency communications is developed. The key principles underlying each sharing model are given, and its applicability is described through illustrative examples, where it is made evident that cognitive radio (CR) technology constitutes a major technological enabler for their realization. Finally, a discussion on the feasibility of each of the spectrum sharing models is addressed.

CFP of Special Issue on Visions on the Future Public Safety Communications

CFP of Special Issue on Visions on the Future Public Safety Communications

Socio-cognitive aspects of interoperability

Emergency communication systems (ECS) are a key element in collaborations among different public safety organizations. The need for interoperability in emergency communication systems has hastened the development of interoperable communication technology that is an enabling technology to automatically identify environmental variables including appropriate radio frequencies and to connect different networks used by different organizations. Even though the technology has been researched from many perspectives and has shown that is possible to connect different organizations, there still remain many issues in terms of socio-cognitive aspects. Thus, this study examines the socio-cognitive dimensions of interoperability, which equal the technical dimensions of the problem in importance. The existential-phenomenological study reported here used semistructured interviews to reconceptualize interoperability in the public safety communication domain. Based on 11 interviews with public safety workers, five important factors were identified that have a major impact on the effectiveness of interoperable groups: information sharedness, operational awareness, communication readiness, adaptiveness, and coupledness. Based on these main concepts, high-level suggestions are provided to guide the design of a new public safety communication system. The results can be directly applied to identify the requirements of communication systems and can be extended to design collaboration systems under stressful environments.

Operations support systems for mission critical public safety communication networks

Mission critical communication networks for public safety have very specific operating requirements. The main objective is to maximize system availability and reliability in cases of disaster or large-scale unplanned events. Based on its experience in communications network operations and the unique requirements of public safety communications, Alcatel-Lucent has developed a new solution concept to support public safety communication network operations. The solution focuses on the different user roles and work processes of a public safety network operator. Supported by intelligent fault handling, evolving correlation rules, enhanced help system, end-to-end work process integration, extended test functionalities, real time status and performance views, and other key functionalities, the solution increases usability and applicability for operations organizations. Open interfaces allow future extensions. The basic principles for the technical implementation are the use of commercial off-the-shelf (COTS) software applications in combination with reference to frameworks such as the enhanced Telecom Operations Map (eTOM) and Information Technology Infrastructure Library (ITIL). Successful reference projects have shown that operations organizations can increase their effectiveness by increasing the amount of information they have available. This, in turn, leads to cost savings and better network performance.

The EULER project: application of software defined radio in joint security operations

The task of improving the effectiveness of public safety communications has become a main priority for governments. This is partly motivated by the increased risk of natural disasters such as flooding, earthquakes, and fires, and partly due to the risks and consequent impact of terrorist attacks. This article focuses on the experience from the European Commission Seventh Framework Programme project known as EULER, which seeks to demonstrate the benefits of software defined radio technology to support the resolution of natural disasters of significant stature, which require the participation of different public safety and military organizations, potentially of different nations. In such scenarios, the presence of interoperability barriers in the disaster area is a major challenge because different organizations may use different wireless communication systems. In this context, the main aspect investigated in EULER is the definition of a common waveform that respects the software communications architecture constraints, and guarantees maximum portability across SDR platforms. This article discusses a range of issues that have been identified thus far within the EULER project; in particular, the perceived pan-European interoperability needs of public safety, and coordination with military devices and networks. Aspects of interoperability are also extended to the three dimensions of platform, waveform, and information assurance.

Privacy Enhanced Key Agreement for Public Safety Communication in Wireless Mesh Networks

With the requirements of mobility, flexibility, and rapid response, wireless mesh networks are widely used for emergency services to improve the efficiency of public safety communication to prevent or respond to incidents that harm or endanger persons or property. In this paper, we propose a practical scheme of key agreement with asymmetric encryption based on station-to-station protocol and a privacy enhanced scheme of key agreement with directed signature using the elliptic curve ElGamal cryptography for public safety communication in wireless mesh networks. In the result, only both participants can gain the shared secret key, however, any party else can not understand the key agreement process clearly. We analyze the properties of security and efficiency of the privacy enhanced scheme of key agreement in comparison to the station-to-station protocol and the practical scheme of key agreement with asymmetric encryption. The results of experiment show that the privacy enhanced scheme of key agreement can provide resistance to the unknown key-share attacks, privacy protection for sensitive information included in signature and better efficiency in terms of computational cost.

Embedding Authentication & Authorization in Discovery Protocols for Standard Based Publish/Subscribe Middleware: A Performance Evaluation

Standard based Pub/Sub middleware, such as OMG Data Distribution Service (DDS), could assume a key role in supporting computer communications requiring continuous state information updating, deterministic deadline to data delivering and real time information adjourning. This kind of capability could be well ex-ploited by Peer-To-Peer (P2P) systems, Internet-wide as long as private ones, like in Public Safety or Civil Protection Communication Systems; but Pub/Sub specifications, and DDS/RTPS (Real Time Publish Sub-scribe) as well, usually do not provide Authentication & Authorization (AA) mechanisms. In the present work two important novelties are assessed: a possible scheme to implement AA in DDS/RTPS networks and a time performance evaluation study about embedded Authentication in RTPS.

MC-FiWiBAN: an emergency-aware mission-critical fiber-wireless broadband access network

The convergence of optical and wireless networks has been envisioned recently as an attractive economic broadband access solution; yet, its usage has been restricted to public users only. To serve mission-critical services in public safety and disaster relief communications using the fiber-wireless integration, key challenges such as fault recovery, security, and quality of service assurance must be addressed. This article introduces MC-FiWiBAN, a new emergency-aware architecture that leverages layer 2 virtual private networks to support mission-critical services over the integration. Each virtual private network corresponds to a specific mission-critical system requirements bundle that is stipulated in the service level agreement and fulfilled via an effective resource management paradigm. Simulation results show that MC-FiWiBAN can commit guaranteed quality of service for emergency and non-emergency services.

Compact and Broadband Antenna for LTE and Public Safety Applications

The antenna presented in this letter employs a stepped T-shape structure in combination with patch tapering and a capacitive feeding mechanism to obtain broad bandwidth (BW). This antenna is specifically designed to operate for US Public Safety (PS) and Long Term Evolution (LTE) wireless communication bands covering 426-861 MHz (68% BW). The radiation pattern over this broad bandwidth remains almost unchanged with good gain flatness. The antenna has a compact three-dimensional structure with lateral dimensions being ~ 0.25 λ in length and height being ~ 0.01 λ at the lowest frequency of operation. The measured and simulated impedance and radiation characteristics results agree well, demonstrating the good performance of the broadband and compact antenna presented in this letter.

A novel communication infrastructure for emergency management: the In.Sy.Eme. vision

AbstractWireless communications have achieved a great attention during the last decades due to the easy implementation, possibility of delivering multimedia services to rural communities, suitability for public safety and emergency communications. In particular, a wireless network designed for an emergency scenario seems to be the best solution to manage all the phases of an emergency situation, from the prevention to the post‐emergency management. This paper discusses the main features of a such wireless network aiming to interconnect several heterogeneous systems and providing multimedia access to groups of people involved in emergency operations as foreseen by the In.Sy.Eme. (Integrated System for Emergency) project. In particular, the focus here will be on a communication infrastructure able to efficiently support a pervasive high performance distributed elaboration structure based on the Next Generation Grid principle. Main scope of the proposed system is that of allowing functional integration of new technologies with actual or off‐the‐shelf technologies to provide fast responses to any emergency situations and efficient use of all available resources. Copyright © 2009 John Wiley & Sons, Ltd.

IMPROVED PACKET FORWARDING APPROACH IN VEHICULAR AD HOC NETWORKS USING RDGR ALGORITHM

VANETs (Vehicular Ad hoc Networks) are highly mobile wireless ad hoc networks and will play an important role in public safety communications and commercial applications. Routing of data in VANETs is a challenging task due to rapidly changing topology and high speed mobility of vehicles. Position based routing protocols are becoming popular due to advancement and availability of GPS devices. One of the critical issues of VANETs are frequent path disruptions caused by high speed mobility of vehicle that leads to broken links which results in low throughput and high overhead . This paper argues the use of information on vehicles' movement information (e.g., position, direction, speed of vehicles) to predict a possible link-breakage event prior to its occurrence. So in this paper we propose a Reliable Directional Greedy routing (RDGR), a reliable position based routing approach which obtains position, speed and direction of its neighboring nodes from GPS. This approach incorporates potential score based strategy, which calculates link stability between neighbor nodes in distributed fashion for reliable forwarding of data packet.

Modeling mobility in disaster area scenarios

This paper provides a model that realistically represents the movements in a disaster area scenario. The model is based on an analysis of tactical issues of civil protection. This analysis provides characteristics influencing network performance in public safety communication networks like heterogeneous area-based movement, obstacles, and joining/leaving of nodes. As these characteristics cannot be modeled with existing mobility models, we introduce a new disaster area mobility model. To examine the impact of our more realistic modeling, we compare it to existing ones (modeling the same scenario) using different pure movement and link-based metrics. The new model shows specific characteristics like heterogeneous node density. Finally, the impact of the new model is evaluated in an exemplary simulative network performance analysis. The simulations show that the new model discloses new information and has a significant impact on performance analysis.

Design and Implementation of a Portable Software Radio

We summarize the design and development of a portable software radio prototype built primarily using commercial off-the-shelf components and open source software. Our research group leverages these prototypes for several funded projects focusing on issues including interoperable public safety communications, cognitive wireless networks, and educational initiatives. The device components include a general-purpose processor on a small-form-factor motherboard, radio hardware, touchscreen and LCD, audio microphone and speaker, and an internal battery enabling hours of mobile operation. We describe the selection of hardware and software components, identification and modification of the operating system, and development of an application programming framework that augments the selected radio software. We discuss trade-offs in the selection of hardware and software, decisions that proved to be stable throughout the lifetime of the project, issues that arose, and lessons learned along the way. Significant advances over the past decade have made GPP-based software radio a viable solution in many areas, and this work demonstrates that today's processors are capable of enabling a new generation of software radio in portable form factor devices.

Toward a Next Generation Architecture for Public Safety Communications

In the aftermath of Hurricane Katrina, a unitary reliance on Land Mobile Radio systems (LMRs) failed public safety agencies, leaving them without any source of communications once they lost transmission capability. Unfortunately, in the wake of this tragedy, many have dusted off traditional prescriptions for improving public safety communications, such as more dedicated spectrum and more money for single-purpose LMRs (or LMRs based on technology that fails to facilitate broader functionalities). As we explain, however, both the needs underscored by Katrina and the capabilities made possible by emerging technologies call for a different strategy. In this paper, we argue that sound policy favors adoption of a next generation flexible architecture strategy for public safety communications. Such a flexible architecture embraces technological convergence and, accordingly, strives to coordinate existing LMRs, commercial terrestrial services, satellite technology, and wireless broadband systems to provide a robust, reliable, secure, and interoperable broadband communications system. Additionally, this approach would take advantage of radios which are already a reality in most segments of the marketplace (except for public safety). Such multi-mode radios are expected to be even more robust once the recently authorized ancillary terrestrial component (ATC) of mobile satellite services becomes an option for public safety agencies. Notably, the flexible architecture that we advocate does not necessarily require additional spectrum dedicated for public safety agencies nor prohibitive financial investment in the equipment needed to use spectrum effectively. Rather, public safety agencies can leverage networks provided by commercial providers - particularly hybrid satellite and terrestrial systems - to satisfy many public safety needs in a cost-effective fashion. To advance this vision, policymakers should ensure that (1) satellite and terrestrial providers are afforded the opportunity - through pro-market and innovative spectrum policies - to develop effective offerings for public safety agencies; and (2) public safety agencies receive sufficient financial support to promote this type of a hybrid, next generation architecture.

Wireless Mesh Networks for Public Safety and Crisis Management Applications

Wireless mesh networks (WMNs) are multihop wireless networks with self-healing and self-configuring capabilities. These features, plus the ability to provide wireless broadband connectivity at a comparatively low cost, make WMNs a promising technology for a wide range of applications. While discussing the suitability of WMN technology for public safety and crisis management communication, this article highlights its strengths and limitations and points to current and future research in this context.

How America's fragmented approach to public safety wastes money and spectrum

Emergency responders such as firefighters, police, and paramedics depend on reliable and ubiquitous wireless communications. Failures in these communications systems can cost lives. Particularly since 9/11, there has been great concern in the US about the possibility of failures due to lack of interoperability, and failures due to a shortage of public safety spectrum. This paper shows how both of these and other serious problems are a logical consequence of America's fragmented approach to public safety, in which thousands of local agencies make independent decisions without a coherent strategy to unify or guide them. Because of this fragmented approach, public safety agencies build more infrastructure than they should, spend more tax-payer money than they should, and consume more scarce spectrum than they should, all for a system that is unnecessarily prone to interoperability failures. This paper also considers the most widely cited estimates of public safety's spectrum needs, which predict a serious shortage unless considerably more spectrum becomes available to public safety by 2010. This paper shows that estimates for the amount of spectrum needed in 2010 would be vastly lower if the US adopted an effective national strategy that included coordinated planning and modern technology. On the other hand, if the US retains today's fragmented approach, regions where coordination among local public safety agencies is particularly weak may need more spectrum than popular estimates would indicate, leading to an even greater shortage. Thus, the federal government should start playing a large role in setting the direction of public safety communications, rather than leaving this to many independent local governments.

Public safety and commercial spectrum sharing via network pricing and admission control

Public safety and commercial communications have distinct performance objectives. The former requires a high availability (i.e., low blocking), both in normal times and during a disaster, whereas the latter requires a high network revenue performance in normal times. Therefore, public safety and commercial communications traditionally use separate networks, which results in either spectrum inefficiency or unsatisfactory performance. In this paper, we propose a public safety and commercial spectrum sharing strategy via intelligent network pricing and call admission control. We provide a precise characterization of the performance objectives of such a sharing strategy, which is to maximize the commercial revenue while guaranteeing a low blocking probability to public safety calls. We demonstrate through analysis and simulation that our sharing strategy simultaneously satisfies the objectives of both types of communications

Improving Public Safety Communications: An Analysis of Alternative Approaches

There is a broad consensus that the communication capabilities of America’s public safety agencies need to be improved. Public safety communications systems are not interoperable, making it difficult for agencies to communicate with one another. Moreover, these systems generally do not provide the broadband capabilities that are increasingly commonplace in commercial cell phones. In December 2006, the FCC proposed a “national, centralized approach to maximize public safety access to interoperable, broadband spectrum.” The FCC plan aimed to ensure efficient and effective use of the spectrum provided to public safety, while promoting “the deployment of advanced broadband applications, related radio technologies, and modern, IP-based architectures.” In 2007, a company called Cyren Call proposed allocating of an additional 30 MHz of spectrum to construct a nationwide broadband network which would be used for both commercial and public safety purposes. This paper presents our analysis of the Cyren Call proposal. We find that the plan suffers from serious flaws, and that its adoption would not result in more effective communications solutions for public safety. In addition, we find that sufficient spectrum has already been allocated for public safety use, and that more efficient spectrum management and the adoption of modern wireless technology can provide the interoperability and advanced capabilities public safety agencies need.

Evolving public safety communication systems by integrating WLAN and TETRA networks

This article contributes to the evolution of public safety communication systems by specifying a novel solution for integrating WLAN and Terrestrial Trunked Radio (TETRA) networks. The specified solution allows TETRA terminals to interface to the TETRA Switching and Management Infrastructure (SwMI) over a broadband WLAN radio access network, instead of the conventional narrowband TETRA radio network. These terminals are fully interoperable with conventional TETRA terminals and can employ all TETRA services, including group calls, short data messaging, packet data, and so forth. In addition, however, such terminals can support a range of brand new capabilities enabled by the WLAN, such as broadband data services, true concurrent voice and data services, simultaneous reception of many group calls, reduced call setup and voice transmission delays, improved voice quality, and so forth. The specified solution is solely based on IP multicast and Voice-over-IP (VoIP) technologies and thus fits ideally to the all-IP architecture being introduced by the MESA project for the next generation of public safety and disaster relief communication systems.

Spectrum considerations for public safety in the United States

Since the inception of mobile radio, public safety agencies have relied on wireless communication systems to coordinate day-to-day and emergency operations. The decentralized and autonomous nature of the various public safety agencies in the United States has led to the deployment of a variety of systems operating in a fragmented spectrum, ranging from lower VHF to upper UHF. Due to the narrowband technologies used in public safety communications systems, public safety agencies have been limited primarily to voice services and low-speed data transfer on their private networks. In contrast, the commercial cellular sector now offers a large portfolio of services that include voice, messaging, email, Web browsing, picture transfer, video streaming, and other wideband services. In this article, some of the factors driving the expansion of spectrum allocated to public safety agencies arc described.