No. 2 (2021)
Published:
2021-06-30
Preface
ARTICLES FROM THIS ISSUE
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Digital Predistortion of Wideband Signals with Reduced Complexity Based on Feedback Wiener System
Abstract
Digital predistortion (DPD) using baseband signals is commonly used for power amplifier linearization. This paper is devoted to this subject and aims to reduce DPD complexity. In this study, we propose a structure that allows to decrease the number of DPD parameters by using multiple blocks, with each one of them dedicated to characterizing the non-linear behavior and/or memory effects. Such a structure is based on the feedback Wiener system, involving a FIR filter used as a feedback path to reproduce the PA inverse dynamics. A memory polynomial block (MP) is inserted as the final element to minimize the modeling errors. A relevant model identification method, based on an iterative algorithm, has been developed as well. The proposed architecture is used for the linearization of a commercial class-AB LDMOS RF PA by NXP Semiconductors, in wideband communication systems. Comparison of performance with the conventional generalized memory polynomial model (GMP) shows that the proposed model offers similar results, with its advantage consisting in the reduced number of parameters
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Performance Analysis of Filtered OFDM Based Downlink and Uplink NOMA System over Nakagami-m Fading Channel
Abstract
Efficient consumption of available resources and fulfillment of increasing demands are the two main challenges which are addressed by exploring advanced multiple access schemes along with efficient modulation techniques. To this end, non-orthogonal multiple access (NOMA) is discussed as a promising scheme for future 5G traffic. NOMA enables the users to share same resource block, permitting certain level of interference. In this paper, we propose filtered OFDM (F-OFDM) as a transmission waveform for NOMA systems, as it offers all the advantages of OFDM with the additional provision of sub-band filtering to satisfy the diverse services of the users. We examine F-OFDM in both downlink and uplink NOMA systems. Error-related performances of both downlink and uplink F-OFDM NOMA systems are analyzed and compared with conventional OFDM NOMA system over Nakagami-m fading channel. The results show that the error performance of F-OFDM NOMA is better than that of OFDM NOMA. An improvement of about 2 dB and 1 dB in bit error rate is achieved in downlink and uplink F-OFDM NOMA, respectively. Monte Carlo simulations are conducted for different values of fading parameter m, supporting the obtained analytical results
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LEES: a Hybrid Lightweight Elliptic ElGamal-Schnorr-Based Cryptography for Secure D2D Communications
Abstract
Device-to-device (D2D) communications in 5G networks will provide greater coverage, as devices will be acting as users or relays without any intermediate nodes. However, this arrangement poses specific security issues, such as rogue relays, and is susceptible to various types of attacks (impersonation, eavesdropping, denial-of-service), due to the fact that communication occurs directly. It is also recommended to send fewer control messages, due to authenticity- and secrecyrelated prevailing requirements in such scenarios. Issues related to IoT applications need to be taken into consideration as well, as IoT networks are inherently resource-constrained and susceptible to various attacks. Therefore, novel signcryption algorithms which combine encryption with digital signatures are required to provide secure 5G IoT D2D communication scenarios in order to protect user information and their data against attacks, without simultaneously increasing communication costs. In this paper, we propose LEES, a secure authentication scheme using public key encryption for secure D2D communications in 5G IoT networks. This lightweight solution is a hybrid of elliptic curve ElGamal-Schnorr algorithms. The proposed scheme is characterized by low requirements concerning computation cost, storage and network bandwidth, and is immune to security threats, thus meeting confidentiality, authenticity, integrity and non-repudiation-related criteria that are so critical for digital signature schemes. It may be used in any 5G IoT architectures requiring enhanced D2D security and performance
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Residual Energy-Aware Clustering Transformation for LEACH Protocol
Abstract
Energy is one of the crucial performance parameters in wireless sensor networks (WSNs). Enhancement of network lifetime is an important consideration as well. Low energy-aware clustering hierarchy (LEACH) is one of the protocols proposed for WSNs. In this paper, a residual energy-aware clustering transformation protocol for LEACH (REACT-LEACH), enhancing performance of LEACH by introducing a clustering mechanism, is proposed. The proposed cluster head (CH) rotation and cluster reformation processes are more effective in REACT-LEACH, as residual energy is considered to be one of the metrics. Performance of REACT-LEACH is validated based on simulations
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Political and Economic Contexts of Implementing 5G in Poland and in Selected European Countries
Abstract
The technology race to achieve the position of an economic leader is a phenomenon that has been taking place all over the world. The 5G technology has become a vital component of this race over the recent years. The technical capabilities it offers and the role it may play in the economy have become the subject of political debate and are at the very core of the “war for technology” between two superpowers: China and the United States. The European Union is aware of the fact that the position Europe enjoys on the international arena depends, to a large extent, on how quickly European countries will develop and implement 5G. Are individual European member states capable of seamlessly implementing the assumptions of strategies and plans concerned with the development of 5th generation technologies? Will the security of 5G networks be ensured in Europe? These are just some of the issues that are analyzed in this article with their economic and political context taken into consideration. A broader perspective is presented, with primary focus on the global geopolitical situation and on the conflict between China and the United States. The study was conducted by relying on an in-depth analysis of strategic state documents, reports drawn up by institutions tasked with implementing and monitoring the development of 5G technology, as well as literature on the subject and online resources
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Ka Band-pass Filter Based on SIW Technology for Wireless Communications
Abstract
The paper proposes a new third-order Chebyshev bandpass filter based on the substrate integrated waveguide (SIW) manufacturing technology using an inductive iris and a defected ground structure (DGS) station to resonate in the Ka frequency band, intended for wireless communication applications. All steps that are necessary for designing such a filter have been described in detail based on specific analytical equations harnessed to calculate the different synthesizable parameters of the proposed band-pass filter design, such as the coupling matrix, quality coefficients and initial geometric dimensions. The filter’s ideal frequency response is extracted from an equivalent circuit employing localized elements developed with the use of Design Microwave Office Software. Otherwise, HFSS is employed to set the initial parameters of the proposed topology that will not meet the target specifications defined previously. Accordingly, optimization procedures are necessary for different SIW band-pass filter parameters to reach a high frequency response for the proposed design. The detailed results presented show high efficiency of the SIW technology that offers good performance with lower filter volumes. Two topologies have been developed and then optimized to demonstrate the usefulness of EM software
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Vlasov Launcher Diagrammatic Design Using the RT Method
Abstract
In this paper, a simple and fast method relied upon for designing a Vlasov launcher with a helical cut is proposed. The method is based on graphic interpretation of analytical relationships that link wave parameters (EM field mode) to the launcher’s geometrical dimensions. Using the ray tracing method, a simplified graphic analysis may be carried out. The results obtained are not significantly different from those of rigorous full-wave analyzes. The family of normalized curves that is created in the process greatly facilitates the stage of optimizing the geometrical parameters of the Vlasov launcher
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Analysis of the Discrete-time Multi-queue System with a Cycle-based Scheduler
Abstract
This paper presents an analysis of a discrete-time multi-queue system handling a number of packet streams. The analysis focuses on calculating system state distribution and packet sojourn time distribution. The method relied upon for determining system state distribution is based on creating a number of equations that are solved numerically. Next, based on the distribution calculated in such a manner, we derive relations for packet sojourn time distribution. The models studied may be useful for instance in a system supporting a number of virtual links (each of a constant bitrate) that share a common physical link. Isolation of performance of those virtual links needs to be assured. Finally, we present some exemplary numerical results showing the usefulness of the proposed analysis for supporting the system dimensioning process
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5G New Business Opportunities – New Business Models, Pricing, and Use Cases
Abstract
This paper addresses how network operators may gain a reasonable return on their investment into 5G infrastructure. It first considers the 5G mobile network costs structure then applies this to three typical use cases
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5G Is Out There: How to Ride the Market Storm and Thrive
Abstract
We examine the changes in the commercial model adopted by the mobile ICT industry, due to the advent of 5G technology. This includes consideration of the challenges involved in rolling out a new infrastructure, which new markets this is likely to open up and how this affects partnering decisions. We show that as technology horizons expand, their degree of overlap increases and previously complimentary technologies may compete with each other, impacting the size of the addressable market. It is expected that 5G, whilst supporting its existing markets, will offer additional machine to machine, low latency and highly reliable services. We consider the synergies and the drivers for adoption for the wider 5G propositions and consider the impetus for more bandwidth and services and how the new technology impacts selling approaches. We identify the risks and uncertainties for the network providers and the likely requirements for a sustainable 5G business model and will describe our view of the steps necessary for a 5G successful outcome
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C-V2X Communications for the Support of a Green Light Optimized Speed Advisory (GLOSA) Use Case
Abstract
Rapid expansion of 5G affects a number of sectors, including vehicular communications relying on cooperative intelligent transportation systems (C-ITS). More specifically, in the context of the Internet of Vehicles (IoV), a particular emphasis is placed on modern cellular V2X (C-V2X) technologies aiming to further improve road safety. This work originates from the detailed scope of the ongoing 5G-DRIVE research project promoting cooperation between the EU and China, with the aim of demonstrating IoV services that rely on vehicle-to-infrastructure (V2I) communications. With the C-V2X approach serving as a point of departure, we analyze and describe a specific green light-optimized speed advisory (GLOSA) use case, for which we provide a detailed descriptive framework, a proposed architectural framework for trials, as well as specific KPIs for the joint assessment of trials between the EU and China. We also discuss the context for performance test procedures to be conducted as part of the intended trials. GLOSA provides end-users with short-term information on upcoming traffic light status to optimize traffic flows, help prevent speed limit violations, improve fuel efficiency, and reduce pollution
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Security Verification in the Context of 5G Sensor Networks
Abstract
In order to develop reliable safety standards for 5G sensor networks (SN) and the Internet of Things, appropriate verification tools are needed, including those offering the ability to perform automated symbolic analysis process. The Tamarin prover is one of such software-based solutions. It allows to formally prove security protocols. This paper shows the modus operandi of the tool in question. Its application has been illustrated using an example of an exchange of messages between two agents, with asynchronous encryption. The scheme may be implemented, for instance, in the TLS/DTLS protocol to create a secure cryptographic key exchange mechanism. The aim of the publication is to demonstrate that automated symbolic analysis may be relied upon to model 5G sensor networks security protocols. Also, a use case in which the process of modeling the DTLS 1.2 handshake protocol enriched with the TCP SYN Cookies mechanism, used to preventing DoS attacks, is presented
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Machine Learning-Based Small Cell Location Selection Process
Abstract
In this paper, the authors present an algorithm for determining the location of wireless network small cells in a dense urban environment. This algorithm uses machine learning, such as k-means clustering and spectral clustering, as well as a very accurate propagation channel created using the ray tracing method. The authors compared two approaches to the small cell location selection process – one based on the assumption that end terminals may be arbitrarily assigned to stations, and the other assuming that the assignment is based on the received signal power. The mean bitrate values are derived for comparing different scenarios. The results show an improvement compared with the baseline results. This paper concludes that machine learning algorithms may be useful in terms of small cell location selection and also for allocating users to small cell base stations
