The paper elaborates on the technological and architectural innovations researched and developed by 5G-PPP Phase 1 projects and covering innovation areas such as 5G system design and evaluation, novel air interfaces, network management and security as well as virtualization and service deployment aspects.

This Special Issue originates from the international conference EuCNC2016, which was held in June 2016 in Athens, Greece. Initially, it publishes some key contributions presented at the conference describing different aspects in the most recent 5G (5th generation) activities in the areas of Air Interfaces and Management Technologies. The series continues with further articles in the context of the same area. 5G mobile networks/wireless systems are the next step of mobile telecommunication standards, offering services and speed far beyond what 4G may offer. The most recent research activities focus on the development of 5G communications and networks, aiming to be fully available for the consumers through their devices by 2020. The scope of this Special Issue is to focus on aspects like 5G communications and networks technologies and more specifically Air Interfaces and Management Technologies. In the context of this Special Issue, numerous high-quality papers were received. After rigorous peer review, the following papers have been accepted and included in the Special Issue.

Standardization activities are recognized as one of the tools to incubate research results and accelerate their transfer to innovative marketable products and services. However, the European Commission (EC) research community and its associated stakeholders acknowledge the lack of research transfer via the standardization channel, generally referred to as the research-to-standardization gap. This chapter analyzes the root causes for this gap and proposes way forward. In particular research-focused standardization is considered as the instrument to address this issue. This chapter shows that pre-standardization should be supplemented by a methodology and its associated process aiming to systematically analyze the standardization aspects of research projects and by helping them out to draw their standardization strategy.

The B3G concept can be realized in two complementary ways. The first solution is the integration of the diverse radio access technologies into one composite radio environment. The alternative solution is provided by the concept of reconfigurable (adaptive) networks. Composite radio networks, sometimes also referred to as cooperative networks, jointly handle a difficult condition. Reconfigurable networks on the other hand, support B3G Systems by providing technologies that enable network elements and terminals to dynamically adapt to the environment requirements and conditions, in principle, by means of self-management. This paper provides proof on the business advantages of reconfigurable networks. In this context the paper performs an evaluation of the investment in both composite radio and reconfigurable networks, presenting a methodology that can be used for the financial assessment of such networks by applying investment appraisal techniques. Concrete results for both cases are presented and analyzed. The analysis clearly proves that reconfigurable networks can provide significant business benefits for network operators.

The unparalleled evolution of wireless communications is reflected in the tremendous investments on research and development, targeted at the continuous introduction of innovations that could serve the information society. This has led to the coexistence and complementary exploitation of versatile, legacy and also emerging radio access technologies (RATs), such as: wireless wide area networks (such as 2G/2.5G/3G/3G? mobile communications, the IEEE 802.16 suite and WiMAX), broadcasting technologies, wireless short range networks (such as WLANs/WPANs and wireless sensor networks). Moreover, the wireless world is currently migrating towards the B3G (Beyond the 3rd Generation) era. In the B3G era, network operators (NOs) will have to address increased complexity due to the heterogeneity of the network and terminal infrastructure, the ever-increasing user requirements, the co-existence and need for complementary exploitation of various RATs. A NO should rely on different RATs for raising the customer satisfaction, and achieving the required quality of service (QoS) levels, cost-effectively. We received numerous high quality contributions in this field. After impartial review, we accepted five papers. The papers selected for this special issue address research problems from terminals to networks and from Spectrum and Radio Resource Management to applications.

As a leader in telecommunications, Alcatel-Lucent recognizes the important role our industry must play in the global effort to address environmental issues such as climate change. This article highlights some of the corporation's major research and development initiatives.

Future wireless systems are expected to be characterized by the coexistence of different radio access technologies (RATs) resulting in complex heterogeneous wireless environments. In parallel with this, the tremendous demand for spectrum has inspired the requirement of dynamic spectrum management (DSM). This paper aims at designing a cell based dynamic spectrum management (CBDSM) scheme to enhance the spectrum utilization and maximize the profit of operators in wireless heterogeneous networks. The system architecture and the functional modules supporting the CBDSM scheme are designed. As a fundamental issue in spectrum management, the inter-system interference issue is solved in the proposed CBDSM scheme. Furthermore, game theory, which is a potential tool for studying the distributed autonomous resource optimization algorithms, is applied to design a spectrum trading algorithm enabling the heterogeneous wireless networks to dynamically trade spectrum and to share the profit. In the algorithm, we take into account the economic value of the spectrum of wireless systems in order to guarantee the rationality for the spectrum trading. The simulation results show that the proposed CBDSM scheme effectively improves the spectrum utilization and the profit of operators while it reduces the mutual interference between wireless networks to a tolerable level.

The unparalleled evolution of wireless communications is reflected in the tremendous investments on research and development, targeted at the continuous introduction of innovations that could serve the information society. This has led to the coexistence and complementary exploitation of versatile, legacy and also emerging Radio Access Technologies (RATs). At the same time, the continuously varying environment/users requirements impose the adaptation of those technologies to external stimuli, through reconfiguration (reconsideration) of their infrastructure and/or operating parameters. One feasible option to tackle the increased complexity of such environments, is to design wireless infrastructures with learning capabilities, thus forming cognitive networks. Cognitive networks are able to retain information from their interactions with the environment and intelligently adapt to any requirements. A prerequisite to facilitate operability of cognitive networks is the development of novel management mechanisms, which need to, distributively (centralized approaches would get even more complex), evaluate changes in external conditions and determine the way in which the network will properly respond to them. To this effect, this paper presents a complete framework under which Cognitive Access Points (CgAPs) could be managed and analyzes the functionality of its entities. Moreover, it also provides an approach for managing Cognitive Wireless Network Segments (CgWNSs).

This contribution presents the system concept approach introduced by the IEEE 1900.4 Working Group(WG) and discusses inherent advantages and issues. This effort targets reconfigurable (Software Defined Radio (SDR) based) networks and terminals in a heterogeneous wireless environment, with multi-homing capable terminals which enables them to operate several wireless links simultaneously. In order to ensure backwards compatibility to legacy standards, this approach introduces three new building blocks into the (existing and/or evolving) heterogeneous landscape: i) A Network Reconfiguration Management module, ii) a Radio Enabler and iii) a Terminal Reconfiguration Management module. Within this paper, the key functionalities of these building blocks are presented and discussed; it is furthermore shown how the introduction of distributed decision-making concepts improves the efficiency of the heterogeneous system in terms of i) signaling overhead, ii) reactivity of user mobile terminals (MTs) and iii) numerical resource selection optimization complexity on the network side.

The heterogeneity and complexity of B3G wireless infrastructures dictates the need for novel functionality, in order to deliver enhanced services and meet user requirements. Cognitive networks comprising reconfigurable elements are an effective response towards this direction. The application of autonomic computing principles has the potential of tackling the complexity of managing heterogeneous environments. In this light, this paper introduces innovative functionality targeting at the autonomic management of access points. Four functional components are identified and detailed. A preliminary approach for the deployment of the platform on network infrastructures is also outlined.

This paper describes the end-to-end reconfigurability (E2R II) research framework and focuses on the current status of the activities inside the consortium. E2R II is a partly funded project inside the Sixth Framework Programme of European Community. The E R II project is part of a wider program, started with the E2R I project in 2004. In this program, concepts and solutions in order to enable, manage and control the end-to-end connectivity in highly heterogeneous environments are developed, taking into account the different radio access technologies potentially active (2G/3G cellular, 4G/B3G, IEEE 802.xx, broadcast...). The key objective of the E R II project is to devise, develop, trial and showcase architectural design of reconfigurable devices and supporting system functions with the aim to offer an extensive set of operational choices to the users, application and service providers, operators, manufacturers and regulators in the context of heterogeneous systems.

For cognitive radio one of the most challenging issue is how to get the intelligence necessary to make the best possible allocation decision. Techniques such as sensing to get the information on the occupancy of the radio environment are being discussed. And designing terminals with scanning/sensing capabilities is a vibrant research topic; such terminals, and the sensing principles, can be very helpful when limited parts of spectrum are to be scanned. But in cases where there is no knowledge about the amount of spectrum to be scanned, this can result in time-and power-consuming operations. An alternative approach, described in this paper, consists of a "Cognition supporting Pilot Channel" (CPC) which directly provides relevant information to the terminal. This paper looks at the concept of this CPC, it initially describes the expected functionality and discusses the regulatory implications such a cognition supporting pilot channel, in the context of flexible spectrum management faces.