2018_4 - Infocommunications

2018. 4^th Issue

Volume X, Number 4

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/).

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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.

Reference:
DOI: 10.36244/ICJ.2018.4.1
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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.

Reference:
DOI: 10.36244/ICJ.2018.4.2
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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.

Reference:
DOI: 10.36244/ICJ.2018.4.3
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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.

Reference:
DOI: 10.36244/ICJ.2018.4.4
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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.

Reference:
DOI: 10.36244/ICJ.2018.4.5
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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.

Reference:
DOI: 10.36244/ICJ.2018.4.6
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