EDITORIAL Open AccessEmerging Air Interfaces and ManagementTechnologies for the 5G eraPanagiotis Demestichas1*, Emmanuel Protonotarios2, Bernard Barani3, Didier Bourse4 and Victor C. M. Leung5AbstractThis 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 themost recent 5G (5th generation) activities in the areas of Air Interfaces and Management Technologies. The seriescontinues with further articles in the context of the same area.5G mobile networks/wireless systems are the next step of mobile telecommunication standards, offering servicesand speed far beyond what 4G may offer. The most recent research activities focus on the development of 5Gcommunications and networks, aiming to be fully available for the consumers through their devices by 2020. Thescope of this Special Issue is to focus on aspects like 5G communications and networks technologies and morespecifically Air Interfaces and Management Technologies.In the context of this Special Issue, numerous high-quality papers were received. After rigorous peer review, thefollowing papers have been accepted and included in the Special Issue.Context-aware radio resource management below6 GHz for enabling dynamic channel assignment inthe 5G era, authored by Ioannis-Prodromos Belikaidis,Stavroula Vassaki, Andreas Georgakopoulos, AristotelisMargaris, Federico Miatton, Uwe Herzog, Kostas Tsag-karis, Panagiotis Demestichas. Heterogeneous networksconstitute a promising solution to the emerging chal-lenges of 5G networks. According to the specific net-work architecture, a macro-cell base station (MBS)shares the same spectral resources with a number ofsmall cell base stations (SBSs), resulting in increased co-channel interference (CCI). The efficient management ofCCI that has been studied extensively in the literatureand various dynamic channel assignment (DCA)schemes have been proposed. However, the majority ofthese schemes consider a uniform approach for the userswithout taking into account the different quality require-ments of each application. In this work, we propose analgorithm for enabling dynamic channel assignment inthe 5G era that receives information about the interfer-ence and QoS levels and dynamically assigns the bestchannel. This algorithm is compared to state-of-the-artchannel assignment algorithm. Results show an increase ofperformance, e.g., in terms of throughput and air interfacelatency. Finally, potential challenges and way forward arealso discussed.The 5G candidate waveform race: a comparison ofcomplexity and performance, authored by RobinGerzaguet, Nikolaos Bartzoudis, Leonardo Gomes Baltar,Vincent Berg, Jean-Baptiste Doré, Dimitri Kténas, OriolFont-Bach, Xavier Mestre, Miquel Payaró, MichaelFärber and Kilian Roth. 5G will have to cope with a highdegree of heterogeneity in terms of services and require-ments. Among these latter, the flexible and efficient useof non-contiguous unused spectrum for different net-work deployment scenarios is considered a key challengefor 5G systems. To maximize spectrum efficiency, the5G air interface technology will also need to be flexibleand capable of mapping various services to the best suit-able combinations of frequency and radio resources. Inthis work, we propose a comparison of several 5G wave-form candidates (OFDM, UFMC, FBMC, and GFDM)under a common framework. We assess spectral effi-ciency, power spectral density, peak-to-average powerratio, and robustness to asynchronous multi-user uplinktransmission. Moreover, we evaluate and compare thecomplexity of the different waveforms. In addition to thecomplexity analysis, in this work, we also demonstrate* Correspondence: pdemestichas@gmail.com1University of Piraeus, Piraeus, GreeceFull list of author information is available at the end of the article© The Author(s). 2017 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, andreproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link tothe Creative Commons license, and indicate if changes were made.Demestichas et al. EURASIP Journal on Wireless Communications and Networking (2017) 2017:184 DOI 10.1186/s13638-017-0973-5the suitability of Filter Bank Multi-Carrier (FBMC) forspecific 5G use cases via two experimental implementa-tions. The benefits of these new waveforms for the fore-seen 5G use cases are clearly highlighted on representativecriteria and experiments.Efficient Bayesian compressed sensing-based chan-nel estimation techniques for massive MIMO-OFDMsystems, authored by Hayder AL-Salihi and MohammadReza Nakhai. Efficient and highly accurate channel stateinformation (CSI) at the base station (BS) is essential toachieve the potential benefits of massive multiple inputmultiple output (MIMO) systems. However, the achiev-able accuracy that is attainable is limited in practice dueto the problem of pilot contamination. It has recentlybeen shown that compressed sensing (CS) techniquescan address the pilot contamination problem. However,CS-based channel estimation requires prior knowledgeof channel sparsity to achieve optimum performance,also the conventional CS techniques show poor recoveryperformance for low signal to noise ratio (SNR). Toovercome these shortages, in this paper, an efficient chan-nel estimation approach is proposed for massive MIMOsystems using Bayesian compressed sensing (BCS) basedon prior knowledge of statistical information regardingchannel sparsity. Furthermore, by utilizing the commonsparsity feature inherent in the massive MIMO systemchannel, we extend the proposed Bayesian algorithm to amulti-task (MT) version, so the developed MT-BCS canobtain better performance results than the single taskversion. Several computer simulation-based experimentsare performed to confirm that the proposed methods canreconstruct the original channel coefficient more effect-ively when compared to the conventional channel estima-tor in terms of estimation accuracy.RIePDMA and BP-IDD-IC detection, authored by JieZeng, Dan Kong, Bei Liu, Xin Su and Tiejun Lv. Patterndivision multiple access (PDMA) is a non-orthogonalmultiple access (NOMA) scheme which is proposed tomeet the demand of massive connection in the future5G communications. In this paper, we build a randominterleaver (RI) enhanced PDMA (RIePDMA) system bybringing the random interleaver into a PDMA system tofurther improve the overload of PDMA. Furthermore,we analyze several integrated detection and decodingalgorithms with interference cancelation (IC) andpropose the iterative detection and decoding based onbelief propagation and interference cancelation (BP-IDD-IC). Simulation results show that the proposedRIePDMA system can achieve better block error rate(BLER) performance without increasing the complexityof the receiver. Compared with several other integrateddetection and decoding algorithms, the proposed BP-IDD-IC algorithm can get better BLER performance withan acceptable complexity.Performance of emerging multi-carrier waveforms for 5Gasynchronous communications, authored by Mathieu VanEeckhaute, Andre Bourdoux, Philippe De Doncker andFrancois Horlin. This paper presents an extensive andfair comparison among the most promising waveformcontenders for the 5G air interface. The consideredwaveform contenders, namely Filter Bank Multi-Carrier(FBMC), Universal Filtered Multi-Carrier (UFMC),generalized frequency-division multiplexing (GFDM), andresource-block filtered orthogonal frequency-division mul-tiplexing (RB-F-OFDM), are compared to orthogonalfrequency-division multiplexing (OFDM) used in 4G interms of spectral efficiency, numerical complexity,robustness towards multi-user interference (MUI) and re-silience to power amplifier non-linearity. FBMC shows thebest spectral containment and reveals to be almost insensi-tive to multi-user interference. It, however, suffers from itsbad spectral efficiency for short bursts and from its poormultiple input multiple output (MIMO) compatibility.GFDM reveals to be the most promising contender, withthe best spectral efficiency and the smallest complexityoverhead compared to OFDM. It is also the most resilientto multi-user interference after FBMC and is MIMO com-patible as soon as the interference can be managed. UFMCand RB-F-OFDM are finally the closest to OFDM andbenefit, therefore, from a better compatibility with existingsystems, even if their performance is generally lower thanFBMC and GFDM.We would like to thank the authors and reviewers thatparticipated in this Special Issue.Author details1University of Piraeus, Piraeus, Greece. 2National Technical University ofAthens, Athens, Greece. 3European Commission, Brussels, Belgium. 4Nokia,Paris, Nozay, France. 5The University of British Columbia, Vancouver, Canada.Received: 22 September 2017 Accepted: 23 October 2017Demestichas et al. EURASIP Journal on Wireless Communications and Networking (2017) 2017:184 Page 2 of 2