Guest Editorial

Abstract

This is a Special Issue of IET Communications: ‘Green Computing and Telecommunications Systems,’ published in association with the 3rd International Conference on Computing, Management and Telecommunications (ComManTel 2015). There were 30 submissions to the issue, ranging across the subject of green computing and networks. These spanned emerging technologies and methods for green computing, to green wireless and multimedia telecommunications networks, resource allocation, and test-beds for green telecommunication networks. This Special Issue comprises 9 papers (3 of which were extended from papers presented at ComManTel 2015 and invited to submit to the special issue) which were chosen for publication after a rigorous peer review and selection process. The accepted papers cover the energy-efficiency aspects of telecommunications systems, address the requirement for minimising consumed resources whenever possible, propose approaches for green connected energy as well as presenting designs for components of a green wireless system. The paper entitled “Uplink training for multicell massive multiple-input–multiple-output systems: A combination of time-shifted and time-aligned pilot approaches” by H. V. Nguyen, V.-D. Nguyen and O.-S. Shin proposes two schemes to mitigate the effect of pilot contamination with the aim to improve the achievable uplink and downlink rates in a multicell massive multiple-input–multiple-output (MIMO) system. Their results show that the two proposed strategies significantly improve both the achievable uplink and downlink rates when compared with those of a conventional time-aligned pilot strategy and a previously proposed time-shifted pilot strategy. Considering cellular networks having multi-tier heterogeneous architectures in which the channel conditions change rapidly, D.-A. Le, H.V. Vu, M. Ranjbar, N.H. Tran, T. Karacolak and T.-M. Hoang in the paper “On the capacity and energy efficiency of non-coherent Rayleigh fading channels with additive Gaussian mixture noise” examine the capacity and energy efficiency of non-coherent Rayleigh fading channels with Gaussian mixture noise where neither the transmitter nor the receiver has the knowledge of channel state information. The energy efficiency, which is related to the capacity and optimal input in low-power regimes, is examined by calculating the minimum bit energy and wideband slope of the spectral-efficiency curve. Q.-T. Vien, T.A. Le, B. Barn and C.V. Phan adopt non-orthogonal multiple access (NOMA) and propose power allocation for the wireless downlink of a cloud-based central station to multiple base stations in a heterogeneous cloud radio access network (HCRAN) sharing the same time and frequency resources. The energy efficiency of the practical HCRAN utilising NOMA is analysed taking into account practical channel modelling with power consumptions at base stations of different cell types (e.g. macrocell, microcell etc.) and backhauling power. These results are presented in the paper “Optimising energy efficiency of non-orthogonal multiple access for wireless backhaul in heterogeneous cloud radio access network.” For the potential of fully cooperative OFDM in the design of emerging low power applications, such as a wireless body area network comprising wearable computing devices, L.C. Tran and A. Mertins present an analysis of decode-and-forward, space-time coded, fully cooperative OFDM systems from both error performance and energy efficiency perspectives, in identically/non-identically distributed frequency selective Rayleigh fading channels. Results from their paper “Error performance and energy efficiency analyses of fully cooperative OFDM communication in frequency selective fading” demonstrate that the fully cooperative OFDM outperforms direct OFDM transmission with respect to error performance and energy efficiency in many cases. In their paper entitled ‘’Energy efficient medium access scheme for visible light communication system based on IEEE 802.15.7 with unsaturated traffic’’ H. Liu, L. Zhang and M. Jiang propose a medium access scheme for reducing power consumption and improving the random channel access mechanism for multiuser visible light communication (VLC) networks under unsaturated traffic conditions. The proposed scheme is shown to outperform the IEEE 802.15.7 CSMA/CA scheme in terms of average power consumption, system throughput and packet dropping probability. N.-S. Vo, D.-B. Ha, B. Canberk and J. Zhang propose an energy, bandwidth, and quality (EBQ) optimisation framework for green two-tiered wireless multimedia sensor systems, where the first tier contains the camera sensors and the second includes cluster heads selected from the camera sensors with higher available energy and processing capacity. These results are presented in the paper “Green two-tiered wireless multimedia sensor systems: An energy, bandwidth, and quality optimisation framework.” The next two papers in the issue consider energy harvesting techniques in cooperative and cognitive networks. N.T. Do, D.B. da Costa and B. An consider the joint impact of energy harvesting technique and transceiver hardware impairment on the outage performance of multirelay decode-and-forward cooperative networks in their paper “Performance analysis of multirelay RF energy harvesting cooperative networks with hardware impairments”. It is shown that the “harvested energy-based relay selection” scheme achieves a diversity order of 1 and is independent of the relay numbers, while the “channel quality-base relay selection” scheme achieves full diversity. The paper “Impact of primary networks on the performance of energy harvesting cognitive radio networks” by Jinghua Zhang, N.-P. Nguyen, Junqing Zhang, E. Garcia-Palacios and N.P. Le examines the influence of the primary transmitter's transmit power on the energy harvesting secondary network in the presence of multiple power beacons and multiple secondary transmitters. Results reveal that the influence is negative in both the near/far scenarios of the primary transmitter's location to the secondary network. However, it can be alleviated by increasing the number of power beacons and primary transmitters. The paper “Design of compact frequency reconfigurable planar invert-F antenna for green wireless communications” proposes a single frequency reconfigurable planar invert-F antenna (FRPIFA) using PIN diodes based on the changes of shorting pin positions. H.T.P. Thao, V.T. Luan and V.V. Yem also present a frequency reconfigurable multiple-input multiple-output (MIMO) antenna consisting of two single reconfigurable ones with a distance of half-wavelength, which is shown to achieve a high isolation in all operating bands. The proposed compact single and MIMO antennas are demonstrated as suitable for green wireless communication systems. Trung Q. Duong (S′05, M′12, SM′13) received his Ph.D. degree in Telecommunications Systems from Blekinge Institute of Technology (BTH), Sweden in 2012. Since 2013, he has joined Queen's University Belfast, UK as a Lecturer (Assistant Professor). His current research interests include physical layer security, energy-harvesting communications, and cognitive relay networks. He is the author or co-author of more than 230 technical papers published in scientific journals (116 articles) and presented at international conferences (114 papers). Dr. Duong currently serves as an Editor for IEEE Transactions on Wireless Communications, IEEE Transactions on Communications, IEEE Communications Letters and IET Communications. He was an editor of Wiley Transactions on Emerging Telecommunications Technologies, Electronics Letters and has also served as the Guest Editor of Special Issues in some major journals including IEEE Journal in Selected Areas on Communications, IET Communications, IEEE Access, IEEE Wireless Communications Magazine, IEEE Communications Magazine, EURASIP Journal on Wireless Communications and Networking and EURASIP Journal on Advances Signal Processing. He was awarded the Best Paper Award at the IEEE Vehicular Technology Conference (VTC-Spring) in 2013, and the IEEE International Conference on Communications (ICC) 2014. He is the recipient of the prestigious Royal Academy of Engineering Research Fellowship (2016–2021). Vo Nguyen Quoc Bao (SMIEEE) is an associate professor of Wireless Communications at the Posts and Telecommunications Institute of Technology (PTIT), Vietnam. He also served as Dean of the Faculty of Telecommunications and as Director of the Wireless Communication Laboratory (WCOMM). His research interests include wireless communications and information theory with current emphasis on MIMO systems, cooperative and cognitive communications, physical layer security, and energy harvesting. He has published more than 140 journal and conference articles that have 1300+ citations and H-index of 20. He is an Editor of Transactions on Emerging Telecommunications Technologies (Wiley ETT), VNU Journal of Computer Science and Communication Engineering, and REV Journal on Electronics and Communications. He is also a Guest Editor of a EURASIP Journal on Wireless Communications and Networking “Special Issue:Cooperative Cognitive Networks” and an IET Communications “Special Issue: Secure Physical Layer Communications”. He served as a Technical Program co-chair for ATC (2013, 2014), NAFOSTED-NICS (2014, 2015, 2016), REV-ECIT 2015, ComManTel (2014, 2015), and SigComTel 2017. He is a Member of the Executive Board of the Radio-Electronics Association of Vietnam (REV) and the Electronics Information and Communications Association Ho Chi Minh City (EIC). He is currently serving as a scientific secretary of the Vietnam National Foundation for Science and Technology Development (NAFOSTED) scientific Committee in Information Technology and Computer Science. Mohsen Guizani (S′85–M′89–SM′99–F′09) received B.S. (with distinction) and M.S. degrees in electrical engineering, M.S. and Ph.D. degrees in computer engineering from Syracuse University, Syracuse, NY, USA, in 1984, 1986, 1987, and 1990, respectively. He is currently a professor and Electrical and Communications Engineering Department Chair at the University of Idaho. Previously, he was Professor and Associate Vice President of Graduate Studies at Qatar University, Doha, Qatar, served as Chair of the Computer Science Department, Western Michigan University, Kalamazoo, MI, USA, from 2002 to 2006, and Chair of the Computer Science Department, University of West Florida, Pensacola, FL, USA, from 1999 to 2002. He also served in academic positions at the University of Missouri- Kansas City, Kansas City, MO, USA, University of Colorado-Boulder, Boulder, CO, USA, Syracuse University, and Kuwait University, Kuwait City, Kuwait. His research interests include wireless communications and mobile computing, computer networks, mobile cloud computing, and smart grid. He currently serves on the Editorial Boards of many international technical journals and is the Founder and Editor-in-Chief of Wireless Communications and Mobile Computing journal (Wiley). He is the author of nine books and more than 400 publications in refereed journals and conferences. He has guest edited a number of Special Issues in IEEE journals and magazines. He has also served as member, Chair, and General Chair of a number of conferences. He was selected as the Best Teaching Assistant for two consecutive years at Syracuse University (1988 and 1989). He was the Chair of the IEEE Communications Society Wireless Technical Committee and the Chair of the TAOS Technical Committee. He served as the IEEE Computer Society Distinguished Speaker from 2003 to 2005.