Abstract:
The lack of available radio spectrum and inefficiency in its usage necessitate a new communication paradigm requiring to exploit the existing spectrum opportunistically. One of the perspective spectrum sharing methods, which is currently under a heavy investigation by academia and industry as well across whole Europe, is called Licensed Shared Access (LSA). This novel technology allows for controlled sharing of spectrum between an original owner (primary user, incumbent) and a licensee (secondary user), such as the mobile network operators (MNOs), which coexist geographically. Despite certain benefits, there are still several issues to be solved before the LSA framework will be implemented in commercial infrastructure. One of them is the need to move secondary users (SUs) from the rented LSA band whenever the incumbent needs it. The potential solution for this problem is represented by spectrum handoff, which aims to help SUs to vacate the occupied licensed spectrum and find suitable network resources to resume the unfinished transmissions somewhere else. Inspired by this, we propose a decision making model considering several SUs attributes (RSSI, RSRP, RSRQ, SINR) in order to efficiently implement the handoff procedure and treat SUs to maximize total service time, spectrum utilization and SUs satisfaction. As an input for our simulation model, we have used the set of measurements performed in real 3GPP LTE-A indoor cellular system located at Brno University of Technology, Czech republic. Our achieved simulation results evaluate the spectrum utilization of three LTE cells and provide the total service time for each active SU, while different values of primary user’s activity ratio are considered for each cell.

Abstract:
During the past 15 years, the Internet revolution has redefined the industry landscape. The advent of the Internet of Things (IoT) is changing our lives by provisioning a wide range of novel applications that leverage the ecosystem of " smart " and highly heterogeneous devices. This is expected to dramatically transform manufacturing, energy, agriculture, transportation, and other industrial sectors. The Industrial Internet of Things (IIoT) brings along a new wave of Internet evolution and will offer unprecedented opportunities in Machine Type Communications (MTC) — intelligent industrial products, processes, and services that communicate with each other and with people over the global network. This paper delivers a technology overview of the currently utilized Wireless M-Bus communication protocol within the IIoT landscape together with describing a demonstration prototype development. In our trial implementation, the IQRF modules are utilized to be compatible with the protocol of interest. The constructed WM-Bus receiver is further integrated as part of a complex MTC Gateway, which receives the MTC data via a secure communication channel from various types of smart-metering devices.

Abstract:
Nowadays, many emerging technologies, such as Augmented and Virtual reality, require extremely high-rate data transmissions. This imposes an increasing demand on the network throughput, which currently surpasses the capabilities of commercially available wireless communication systems. To address this constraint, some companies are considering the implementation of high-throughput wired technologies, such as optical fibers, as part of their products. This approach is effective in terms of communication link capacity, but on the other hand may bring disadvantages and constraints in terms of user mobility (i.e., the limited length of cables). Therefore, we are currently witnessing much faster development of novel high-rate wireless technologies, which are considered to be enablers for future 5G applications. This paper offers an evaluation of the emerging IEEE 802.11ad (WiGig) wireless technology capable of delivering multi-gigabit data transfer rates. This hands-on assessment aims at real-world experimentation as well as simulation-based study of selected scenarios to assess the usability of the millimeter-wave technology in prospective 5G applications. All of our practical measurements were conducted on the commercially available WiGig-ready Dell D5000 hardware platforms. The obtained data was comprehensively compared with the corresponding simulation scenario in Network Simulator 3.

Abstract:
Device-to-Device (D2D) communication constitutes an emerging network paradigm that promises to unlock decisive capacity gains without the need for expensive cellular resources. However, while deployment of this promising enabler technology in 5G-grade mobile networks is currently underway, the complete understanding of feasible use cases and their respective limitations has not yet been provided in literature. Today, employing D2D connectivity both in human-to-human and machine-to-machine scenarios, the attention of research community focuses on security, privacy, and trust. Inspired by this increasing demand, we provide in this paper a comprehensive summary on our live trial of secure cellular-assisted D2D communication technology within the full-featured 3GPP LTE network deployment. Correspondingly, we describe a novel D2D framework capable of delivering secure direct connectivity even if the managing cellular link is temporarily not available (unreliable), so that communicating devices could continue to exchange confidential data in their private coalitions. To this end, our prototype implementation characterizes the practical capabilities of secure D2D communication in dynamic, urban environments suffering from intermittent 3GPP LTE connectivity.

Abstract:
As next-generation mobile networks are rapidly taking shape driven by the target standardization requirements and initial trial implementations, a range of accompanying technologies prepare to support them with more reliable wireless access and improved service provisioning. Among these are more advanced spectrum sharing options enabled by the emerging Licensed Shared Access (LSA) regulatory framework, which aims to efficiently employ the capacity of underutilized frequency bands in a controlled manner. The concept of LSA promises to equip network operators with the much needed additional spectrum on the secondary basis and thus brings changes to the existing cellular network management. Hence, additional research is in prompt demand to determine the required levels of Quality of Service (QoS) and service provisioning reliability, especially in cases of dynamic geographical and temporal LSA sharing. Motivated by this recent urge and having at our disposal a fully-functional 3GPP LTE cellular deployment, we have committed to implement and trial the principles of dynamic LSA-compatible spectrum management. This paper is our first disclosure on the comprehensive experimental evaluation of this promising technology. We expect that these unprecedented practical results together with the key lessons learned will become a valuable reference point for the subsequent integration of flexible LSA-based services, suitable for inter-operator and multi-tenant spectrum sharing.

Abstract:
The unprecedented growth of today’s cities together with increased population mobility are fueling the avalanche in the numbers of vehicles on the roads. This development led to the new challenges for the traffic management, including the mitigation of road congestion, accidents, and air pollution. Over the last decade, researchers have been focusing their efforts on leveraging the recent advances in sensing, communications, and dynamic adaptive technologies to prepare the deployed road traffic management systems (TMS) for resolving these important challenges in future smart cities. However, the existing solutions may still be insufficient to construct a reliable and secure TMS that is capable of handling the anticipated influx of the population and vehicles in urban areas. Along these lines, this work systematically outlines a perspective on a novel modular environment for traffic modeling, which allows to recreate the examined road networks in their full resemblance. Our developed solution is targeted to incorporate the progress in the Internet of Things (IoT) technologies, where low-power, embedded devices integrate as part of a next-generation TMS. To mimic the real traffic conditions, we recreated and evaluated a practical traffic scenario built after a complex road intersection within a large European city.

Abstract:
Today, direct contacts between users are being facilitated by the network-assisted device-to-device (D2D) technology, which employs the omnipresent cellular infrastructure for the purposes of control to facilitate advanced mobile social applications. Together with its undisputed benefits, this novel type of connectivity creates new challenges in constructing meaningful proximity-based services with high levels of user adoption. They call for a comprehensive investigation of user sociality and trust factors jointly with the appropriate technology enablers for secure and trusted D2D communications, especially in the situations where cellular control is not available or reliable at all times. In this paper, we study the crucial aspects of social trust associations over proximity-based direct communications technology, with a primary focus on developing a comprehensive proof-of-concept implementation. Our recently developed prototype delivers rich functionality for dynamic management of security functions in proximate devices, whenever a new device joins a secure group of users or an existing one leaves it. To characterize the behavior of our implemented demonstrator, we evaluate its practical performance in terms of computation and transmission delays from the user perspective. In addition, we outline a research roadmap leveraging our technology-related findings to construct a holistic user perspective behind dynamic, social-aware, and trusted D2D applications and services.

Abstract:
Decisive progress in 5G mobile technology, fueled by a rapid proliferation of computation- hungry and delay-sensitive services, puts economic pressure on the research community to rethink the fundamentals of underlying networking architectures. Along these lines, the first half of this article offers a first-hand tutorial on the most recent advances in content-centric networking, emerging user applications, as well as enabling system architectures. We establish that while significant progress has been made along the individual vectors of communications, caching, and computing, together with some promising steps in proposing hybrid functionalities, the ultimate synergy behind a fully integrated solution is not nearly well understood. Against this background, the second half of this work carefully brings into perspective additional important factors, such as user mobility patterns, aggressive application requirements, and associated operator deployment capabilities, to conduct comprehensive system-level analysis. Furthermore, supported by a full-fledged practical trial on a live cellular network, our systematic findings reveal the most dominant factors in converged 5G-grade communications, caching, and computing layouts, as well as indicate the natural optimization points for system operators to leverage the maximum available benefits.

Abstract:
Today, the rapid adoption of mobile social networking is changing how and where humans communicate. As a result, in recent years we have been increasingly moving from physical (e.g., face-to-face) to virtual interaction. However, there is also a new emerging category of social applications that take advantage of both worlds, that is, using virtual interaction to enhance physical interaction. This novel form of networking is enabled by D2D communication between/among the laptops, smartphones, and wearables of persons in proximity of each other. Unfortunately, it has remained limited by the fact that most people are simply not aware of the many potential virtual opportunities in their proximity at any given time. This is a result of the very real digital privacy and security concerns surrounding direct communication between «stranger» devices. Fortunately, these concerns can be mitigated with the help of a centralized trusted entity, such as a cellular service provider, which can not only authenticate and protect the privacy of devices involved into D2D communication, but also facilitate the discovery of device capabilities and their available content. This article offers an extensive research summary behind this type of «cellular-assisted» D2D communication, detailing the enabling technology and its implementation, relevant usage scenarios, security challenges, and user experience observations from large-scale deployments.

Abstract:
Internet of Things (IoT) is expected to become a driver in an emerging era of interconnected world through the advanced connectivity of smart devices, systems, and services. IoT goes beyond a broad range of Machine-to-Machine (M2M) communication technologies and covers a wide variety of networking protocols. There exist solutions like MQTT or SIP collecting data from sensors, CoAP for constrained devices and networks, or XMPP for interconnecting devices and people. Also there is a plethora of standards and frameworks (OSGi, AllJoyn) bringing closer the paradigm of IoT vision. However, the main constraint of most existing platforms is their limited mutual interoperability. To this end, we provide a comprehensive description of protocols suitable to support the IoT vision. Further, we advocate an alternative approach to already known principles and employ the SIP protocol as a container for M2M data. We provide description of data structures and practical implementation principles of the proposed structures (JSON and Protocol Buffers are discussed in detail) transmitted by SIP as a promising enabler for efficient M2M communication in the IoT world. Our reported findings are based on extensive hands-on experience collected after the development of advanced M2M smart home gateway in cooperation with the operator Telekom Austria Group.