2019. 1st Issue

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GUEST EDITORIAL

Pál Varga
Infocommunications Journal: over 10 years – HTE: over Seven Decades 
INFOCOMMUNICATIONS – the domain that integrates information technology, telecommunications, audiovisual systems from user access to information storage and processing – has changed our quality of life in the last decades. The everincreasing speed of data-exchange, the ultra-high resolution of affordable visual systems, or the ”extraordinary” storage capacity that we instantly access every day became ”ordinary” – we actually got used to the speed how things change around us. It is not simply that we realize such changes, but we build it into our everyday experience, and improve our ”digitalized skills”: we buy our train tickets, get around abroad, or communicate with our relatives much differently than one decade ago. 

PAPERS FROM OPEN CALL

Ani Bicaku, Christoph Schmittner, Patrick Rottmann, Markus Tauber and Jerker Delsing
Security Safety and Organizational Standard Compliance in Cyber Physical Systems  
In Industry 4.0 independent entities should interoperate to allow flexible and customized production. To assure the parties that individual components are secured to inter-operate, we investigate automated standard compliance. The standard compliance is defined based on given sets of security and safety requirements for which measurable indicator points are derived. Those reflect configurations of systems recommended by security, safety or process management relevant standards and guidelines, which help to demonstrate the state of compliance. We propose in this paper an approach to automate such an assessment when components are inter-operating with each other by using a monitoring and standard compliance verification framework. The framework will assure the parties that services or devices within their organizations operate in a secure and standard compliant way, without compromising the underlying infrastructure.

Dimitris Kanellopoulos
Inter-destination Multimedia Synchronization: A Contemporary Survey  
The advent of social networking applications, media streaming technologies, and synchronous communications has created an evolution towards dynamic shared media experiences. In this new model, geographically distributed groups of users can be immersed in a common virtual networked environment in which they can interact and collaborate in real- time within the context of simultaneous media content consumption. In this environment, intra-stream and inter-stream synchronization techniques are used inside the consumers’ playout devices, while synchronization of media streams across multiple separated locations is required. This synchronization is nown as multipoint, group or Inter-Destination Multimedia Synchronization (IDMS) and is needed in many applications such as social TV and synchronous e-learning. This survey paper discusses intraand inter-stream synchronization issues, but it mainly focuses on the most well-known IDMS techniques that can be used in emerging distributed multimedia applications. In addition, it provides some research directions for future work.

Cebrail Çiflikli and Musaab Alobaidi
Combining Alamouti Scheme with Block Diagonalization Beamforming precoding for 5G Technology over Rician Channel  
Wireless communication faces a number of adversities and obstacles  as a result of fading and co-channel interference (CCI). Diversity with beamformer techniques may be used to mitigate degradation in the system performance. Alamouti space-time-block-code (STBC) is a strong scheme focused on accomplishing spatial diversity at the transmitter, which needs a straightforward linear processing in the receiver. Also, high bit-error-rate (BER) performance can be achieved by using the multiple-input multiple-output (MIMO) system with beamforming technology. This approach is particularly useful for CCI suppression. Exploiting the channel state information (CSI) at the transmitter can improve the STBC through the use of a beamforming precoding. In this paper, we propose the combination between Alamouti STBC and block diagonalization (BD) for downlink multi-user MIMO system. Also, this paper evaluates the system performance improvement of the extended Alamouti scheme, with the implementation of BD precoding over a Rayleigh and Rician channel. Simulation results show that the combined system has performance better than the performance of beamforming system. Also, it shows that the combined system performance of extended Alamouti outperforms the combined system performance without extended Alamouti. Furthermore, numerical results confirm that the Rician channel can significantly improve the combined system performance.

Gang Qiao, Zeeshan Babar, Lu Ma and Xue Li
Cost Function based Soft Feedback Iterative Channel Estimation in OFDM Underwater Acoustic Communication  
Underwater Acoustic (UWA) communication is mainly characterized by bandwidth limited complex UWA channels. Orthogonal Frequency Division Multiplexing (OFDM) solves the bandwidth problem and an efficient channel estimation scheme estimates the channel parameters. Iterative channel estimation refines the channel estimation by reducing the number of pilots and coupling the channel estimator with channel decoder. This paper proposes an iterative receiver for OFDM UWA communication, based on a novel cost function threshold driven soft decision feedback iterative channel technique. The receiver exploits orthogonal matching pursuit (OMP) channel estimation and low density parity check (LDPC) coding techniques after comparing different channel estimation and coding schemes. The performance of the proposed receiver is verified by simulations as well as sea experiments. Furthermore, the proposed iterative receiver is compared with other non-iterative and soft decision feedback iterative receivers.

Zhongqiang Luo, Wei Zhang, Lidong Zhu and Chengjie Li
Minimum BER Criterion Based Robust Blind Separation for MIMO Systems  
In this paper, a robust blind source separation (BSS) algorithm is investigated based on a new cost function for noise suppression. This new cost function is established according to the criterion of minimum bit error rate (BER) incorporated into maximum likelihood (ML) principle based independent component analysis (ICA). With the help of natural gradient search, the blind separation work is carried out through optimizing this constructed cost function. Simulation results and analysis corroborate that the proposed blind separation algorithm can realize better performance in speed of convergence and separation accuracy as opposed to the conventional ML-based BSS.

Sergey Smolskiy and Alexander Bortsov
Opto-Electronic Oscillator with Mach-Zender Modulator  
The non-standard opto-electronic oscillator (OEO) operation is discussed in the generation mode of a single-side optical harmonic on the base of external and internal modulation of the laser signal. The OEO mathematical model is formed basing on laser differential equations for the closed radiofrequency network. With the help of the model offered, the phase noise of OEO radiofrequency oscillations is analyzed. It is shown that phase noise reduction in the circuit with external modulation depends not only on the increased laser power and growth of the geometric length of the optical fiber, but on reduction of the laser phase noise.

PRACTICAL PAPERS OF APPLIED RESEARCH

Roland Szabo and Aurel Gontean
Sun Tracker Robotic Arm Optical Distance Measurement Evaluation at Different Positions Using Six Sigma Tools  
This paper presents an optical distance evaluation solution, for a sun tracker robotic arm, with the help of Six Sigma. With the help of statistical tools any measurement system can be evaluated and a measurement system analysis (MSA) can be easily made. Like every measurement system, optical distance measurement can have errors. Six Sigma tools can evaluate the measurement system and can give useful data about its accuracy. Sometimes measurement system evaluation is done twice. First, initial tests are done, after some fine tuning and error correction is performed, and finally a repeated test is done, to show that the measurement errors were corrected.

CALL FOR PAPERS / PARTICIPATION

IEEE/IFIP Network Operations and Management Symposium
IEEE NOMS 2020, Budapest, Hungary

International Conference on Cognitive InfoCommunications
CogInfoCom 2019, Naples, Italy

IEEE International Conference on Sensors and Sensing Technologies
IEEE SENSORS 2019, Montreal, Canada

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2018. 4th Issue

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GUEST EDITORIAL

Eszter Udvary
Selected papers of the CSNDSP 2018 conference  
The 11th IEEE, IET International Symposium on Communication Systems, Networks, and Digital Signal Processing (CSNDSP) was hosted by The Faculty of Electrical Engineering and Informatics at Budapest University of Technology and Economics, Hungary, 18-20 July 2018. Detailed information can be found on its website (http://csndsp2018.com/).

PAPERS OF THE SPECIAL ISSUE

Tongyang Xu, Hedaia Ghannam and Izzat Darwazeh
Practical Evaluations of SEFDM: Timing Offset and Multipath Impairments  
The non-orthogonal signal waveform spectrally efficient frequency division multiplexing (SEFDM) improves spectral efficiency at the cost of self-created inter carrier interference (ICI). As the orthogonal property, similar to orthogonal frequency division multiplexing (OFDM), no longer exists, the robustness of SEFDM in realistic wireless environments might be weakened. This work aims to evaluate the sensitivity of SEFDM to practical channel distortions using a professional experiment testbed. First, timing offset is studied in a bypass channel to locate the imperfection of the testbed and its impact on SEFDM signals. Then, the joint effect of a multipath frequency selective channel and additive white Gaussian noise (AWGN) is investigated in the testbed. Through practical experiments, we demonstrate the performance of SEFDM in realistic radio frequency (RF) environments and verify two compensation methods for SEFDM. Our results show first frequency-domain compensation works well in frequency non-selective channel conditions while time-domain compensation method is suitable for frequency selective channel conditions. This work paves the way for the application of SEFDM in different channel scenarios.

Husam Al-Amaireh and Zsolt Kollár
Overview and Complexity Evaluation of FBMC Transmitter Architectures  
Computational complexity is one of the key factors considered for evaluating transmitter performance of future 5G applications. In this contribution we have chosen Filter Bank MultiCarrier (FBMC) as it is the most possible candidate to replace/coexist with the Orthogonal Frequency Division Multiplexing (OFDM) modulation. In the literature two main design approaches can be found for FBMC: Frequency Spreading (FS) and PolyPhase Network (PPN). From these two structures numerous schemes were derived. These schemes are studied and the complexity (real multiplications and additions) for each scheme is compared. Based on the complexity calculations, the simulation results show that PPN has a better complexity performance compared with FS. Also, the alternative PPN schemes have significant improvement in complexity compared to the standard PPN.

Róbert Horváth, Jean-François Roux, Julien Poëtte and Béatrice Cabon
Optoelectronic mixer with a photoconductive switch for 1550 nm wavelengths  
We demonstrate an optoelectronic mixer based on an ultrafast InGaAs photoconductive switch and its use in an innovative heterodyne detection system for Radio over Fibre transmission. The advantage of the proposed switch is its relatively flat response curve in a wide frequency range up to 67 GHz. Two mixing schemes are presented through I-Q modulated data-stream down-conversion. The data can modulate either the electrical signal or the optical signal. In case the electrical signal is modulated, a mode-locked semiconductor laser diode is used as an optical local oscillator at the self-oscillating frequency of 24.5 GHz. The InP based quantum-dash mode-locked laser emitting in the 1570 nm wavelength range is stabilized by a feedback loop and shows a low phase noise in order to increase the mixing performances of the detection apparatus. In a second experiment, the photoconductive switch is combined with a continuous wave laser to demonstrate the feasibility of down converting an optically provided data-stream with an electrical local oscillator.
 
Yahiea Al Naiemy, Taha Elwi, Lajos Nagy and Thomas Zwick
A Systematic Analysis and Design of a High Gain Microstrip Antenna based on a Single EBG Layer  
In this paper, an Electromagnetic Band Gap (EBG) lens of a single layer is invented to improve the gain of a truncated slotted square patch antenna for the Wi-Fi applications. The proposed EBG lens is structured from 55 planar array. The individual unit cell is basically shaped as a couple of a split concave conductive patch. The proposed EBG struc- ture performance is tested numerically using Finite Integration Technique (FIT) formulations of CSTMWS and analytically using circuit theory. Then, the antenna performance in terms of |S11|, the boresight gain, and radiation patterns are reported and compared to the performance before introducing the EBG lens to identify the significant enhancements. The proposed EBG antenna is simulated numerically inside FIT formulations of CSTMWS time domain (TD) solver. A significant gain enhancement of 11.1 dBi at 2.45 GHz and a front to back ratio (F/B) about 22 dB are achieved after introducing the EBG lens. The antenna performance is validated using a frequency domain (FD) solver based CSTMWS formulations to obtain excellent agreements between the two invoked methods.
 
Balázs Matolcsy and Attila Zólomy
Overcoming the Realization Problems of Wideband Matching Circuits  
During the analytical design process of wideband impedance matching major problems may arise, that might lead to non-realizable matching networks, preventing the successful impedance matching. In this paper two practical design rules and a simplified equation is presented, supporting the design of physically realizable impedance matching networks. The design rules and calculation technique introduced by this paper is summarized, and validated by microwave circuit simulation examples.
 
József Varga, Attila Hilt, József Bíró, Csaba Rotter and Gábor Járó

Reducing operational costs of ultra-reliable low latency services in 5G  
Ultra-reliable low latency (uRLL) communication in 5G dictates the deployment of distributed infrastructure with numerous datacenters for low latency, while hosting ultra-reliable services mandates attended datacenters. This would boost the operational costs of 5G network operators planning country-wide coverage for uRLL services. This paper examines how these operational expenses dominated by administrative costs can be reduced without impacting the quality of the provided uRLL service. Our results indicate that hosting uRLL services in unattended datacenters with increased hardware redundancy schemes can produce significant cost savings.

 

CALL FOR PAPERS / PARTICIPATION

Central European Conference on Cryptology
CECC 2019, Telc, Czech Republic

42nd International Conference on Telecommunications and Signal Processing (TSP)
TSP 2019, Budapest, Hungary

28th European Conference on Networks and Communications
EuCNC 2019, Valencia, Spain

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