Ograniczanie wyników
Czasopisma help
Autorzy help
Lata help
Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 78

Liczba wyników na stronie
first rewind previous Strona / 4 next fast forward last
Wyniki wyszukiwania
Wyszukiwano:
w słowach kluczowych:  5G
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 4 next fast forward last
PL
W artykule przedstawiono w zarysie historię rozwoju łączności bezprzewodowej, a w szczególności telefonii komórkowej. Wykazano, że kolejne generacje telefonii komórkowej są naturalnym rozwojem tej dziedziny techniki i technologia 5G (piąta generacja) jest tylko elementem tego ciągu. W artykule wypunktowane zostały główne obiekcje podnoszone przez ruchy anty-5G oraz wskazano, jak te obiekcje podważyć merytorycznie.
EN
The paper aims at showing the history and development of wireless telecommunication, especially the history of mobile telephony. The paper is to show that the 5G technology is the continuation of technological process and then the results of previous investigations can be extended to 5G technology. The paper shows the main objections which anti-5G people use in their actions and it is also shown how to refute the objections.
PL
Artykuł jest przeglądem drogi, prowadzonej w sieciach telefonii mobilnej w Polsce od uruchomienia komórkowej sieci analogowej w 1992 r. przez kolejne generacje sieci 2G, 3G i 4G do 5G. Omówiono podstawowe cechy i obszary zastosowań sieci 5G, stan ich wdrożenia oraz perspektywy dalszego rozwoju ku sieci 6G.
EN
The paper is an overview of how the mobile network has developed in Poland, from the deployment of the first analogue network in 1992 through subsequent 2G, 3G, and 4G upgrades, to the current 5G network. The 5G system main characteristics and its areas of deployment are presented. The prospects for further development towards 6G are also sketched out.
EN
In this paper, we examine the end-to-end average pairwise error probability (PEP) and output probability (OP) performance of the maximum ratio combining (MRC) based selective decode and forward (S-DF) system over an η–µ scattering environment considering additive white Gaussian noise (AWGN). The probability distribution function (PDF) and cumulative distribution function (CDF) expressions have been derived for the received signal-to-noise (SNR) ratio and the moment generating function (MGF) technique is used to derive the novel closed-form (CF) average PEP and OP expressions. The analytical results have been further simplified and are presented in terms of the Lauricella function for coherent complex modulation schemes. The asymptotic PEP expressions are also derived in terms of the Lauricella function, and a convex optimization (CO) framework has been developed for obtaining optimal power allocation (OPA) factors. Through simulations, it is also proven that, depending on the number of multi-path clusters and the modulation scheme used, the optimized power allocation system was essentially independent of the power relation scattered waves from the source node (SN) to the destination node (DN). The graphs show that asymptotic and accurate formulations are closely matched for moderate and high SNR regimes. PEP performance significantly improves with an increase in the value of η for a fixed value of µ. The analytical and simulation curves are in close agreement for medium-to-high SNR values.
EN
5G is a fifth-generation wireless technology that enables extremely fast data transfers and massive connection capacity. Existing Mobile health technology requires more reliable connection power and data transfer rates. The purpose of this research is to design, analyse, and compare the performance of a bio-inspired lotus-shaped microstrip patch antenna array with two to three radiating elements. The proposed antenna utilizes proximity coupled indirect microstrip transmission line feeding technique operating in the 24 GHz-30 GHz frequency band. The results indicate that performance continues to improve as the number of radiating elements increases. Moreover, each radiating element is loaded with complementary and non-complementary split-ring resonators (SRRs). The performance of the proposed microstrip antenna array is then analysed and compared with and without split-ring resonators. The findings validate that the proposed bio-inspired metamaterial-based microstrip patch array antenna is more reliable and performs better than an antenna without SRRs.
EN
Nowadays, there is a trend to employ adaptive solutions in mobile communication. The adaptive transmission systems seem to answer the need for highly reliable communication that serves high data rates. For efficient adaptive transmission, the future Channel State Information (CSI) has to be known. The various prediction methods can be applied to estimate the future CSI. However, each method has its bottlenecks. The task is even more challenging while considering the future 5G/6G communication where the employment of sub-6 GHz and millimetre waves (mmWaves) in narrow-band, wide-band and ultra-wide-band transmission is considered. Thus, author describes the differences between sub-6 GHz/mmWave and narrow-band/wide-band/ultra-wide-band channel prediction, provide a comprehensive overview of available prediction methods, discuss its performance and analyse the opportunity to use them in sub-6 GHz and mmWave systems. We select Long Short-Term Memory Recurrent Neural Network (RNN) as the most promising technique for future CSI prediction and propose optimising two of its parameters - the number of input features, which was not yet considered as an opportunity to improve the performance of CSI prediction, and the number of hidden layers.
EN
Nowadays, the world is turning into technology, fast internet and high signal quality. To ensure high signal quality, the network planners have to predict the pathloss and signal strength of the transmitted signal at specific distances in the design stage. The aim of this research is to provide a generalized pathloss model to suit the urban area in Muscat Governorate in the Sultanate of Oman. The research covers 5G network pathloss in the Muttrah Business District (MBD) area. It includes Close In (CI) model and Alpha Beta Gamma (ABG) model with 3.45GHz. The results of 5G models were compared with real experimental data in MBD by calculating Root Mean Square Error RMSE. Other cells at MBD area were used for reverification. To validate the modified pathloss models of 5G, they were applied at different cells in Alkhoud area. Furthermore, this paper also deals the effect of Specific Absorption Rate (SAR) on the human brain for ensuring safety due to close proximity to cell towers. The SAR values were calculated indirectly from the electric field strength of different antennas. Calculated results were compared with the international standards defined limits on the human brain.
PL
Opisano część badań zawartych w pracy doktorskiej autorki pt.: Coordinated Radio Resource Management in 5G Systems with Time Division Duplex. Przedstawiono algorytmy umożliwiające koordynację interferencji w sieci komórkowej. W szczególności opisano zaproponowane algorytmy skoordynowanego przydziału zasobów radiowych, jak również międzykomórkowej koordynacji parametrów transmisji, takich jak liczba strumieni danych MIMO oraz schematu modulacji i kodowania, które dodatkowo wspomagają efektywność odbiorników SIC. Ponadto rozwiązano ważny problem złożoności koordynacji transmisji w systemie wielokomórkowym.
EN
This article describes some of the research included in the doctoral dissertation of the author of Coordinated Radio Resource Management in 5G Systems with Time Division Duplex. The article presents the algorithms that allow for the coordination of interference in the cellular network. In particular, the proposed algorithms for the coordinated allocation of radio resources as well as the intercellular coordination of transmission parameters such as the number of MIMO data streams and the modulation and coding scheme, which further support the efficiency of the SIC receivers, have been described. Moreover, the important problem of the complexity of transmission coordination in a multi-cell system is also solved.
EN
This article presents partial result of the PhD thesis on the topic of the Doherty power amplifiers. The design of high-efficiency 3way Doherty amplifier with the use of Wolfspeed CG2H40010 transistors is presented. A newly invented 3-way power splitter architecture is also shown. The proposed splitter and the properties of GaN HEMT technology enable the design of the Inverted 3-way Doherty amplifier in closed, compact form without additional, long phase lines. The amplifier operates in the frequency range from 3.4 to 3.8 GHz and achieves up to 46W of saturated output power with a drain efficiency of 75% at full drive and 53% at 10dB output power back-off.
PL
Przedstawiono częściowe wyniki pracy doktorskiej na temat mikrofalowych wzmacniaczy mocy typu Doherty. Zaprezentowano projekt wysokosprawnego trójdrożnego wzmacniacza typu Doherty z tranzystorami Wolfspeed CG2H40010. Ponadto przedstawiono unikalną konstrukcję trójdrożnego dzielnika mocy, która umożliwiła zaprojektowanie trójdrożnego wzmacniacza typu Doherty w konfiguracji odwróconej. Przedstawiony wzmacniacz charakteryzuje się zwartą konstrukcją, która nie wymaga dodatkowych linii fazowych, co umożliwia poszerzenie pasma pracy. Układ pracuje w paśmie telekomunikacyjnym 3,4 – 3,8 GHz i osiąga w nasyceniu 46 W mocy przy sprawności drenowej 75%. Dla sygnałów o mocy wyjściowej niższej o 10 dB względem nasycenia wzmacniacz uzyskuje sprawność 53%.
EN
This paper presents a wideband planar microstrip antenna based on split ring resonator left-handed metamaterial (SRR-LHM) type at 3.5 GHz frequency for mid-band 5G mobile applications. The need to design a wideband antenna with good gain realising the proposed lower band spectrum for 5G technology is urgently demanded. To meet the requirements, microstrip technology and metamaterial are proposed. Firstly, the microstrip antenna is designed with a square patch and two longitude slots at 3.5 GHz. The metamaterial unit cell is designed individually based on the split ring resonator (left-handed metamaterial) SRR LHM type and then integrated with the developed antenna at the same band. The metamaterial is placed on the ground plane of the microstrip antenna. That will increase the bandwidth accordingly. The proposed metamaterial antenna is simulated and optimised using CST software. A good return loss of greater than 10 dB and impedance bandwidth of 1.04 GHz is obtained. This metamaterial antenna is a good candidate for mid-band 5G applications.
PL
W artykule przedstawiono szerokopasmową planarną antenę mikropaskową opartą na lewoskrętnym metamateriale z rezonatorem pierścieniowym (SRR-LHM) o częstotliwości 3,5 GHz do zastosowań mobilnych 5G w średnim paśmie. Pilnie potrzebna jest potrzeba zaprojektowania anteny szerokopasmowej z dobrym wzmocnieniem, realizującej proponowane dolne pasmo widma dla technologii 5G. Aby sprostać wymaganiom, proponuje się technologię mikropaskową i metamateriał. Po pierwsze, antena mikropaskowa została zaprojektowana z kwadratową łatą i dwoma szczelinami długości geograficznej o częstotliwości 3,5 GHz. Komórka elementarna metamateriału jest projektowana indywidualnie w oparciu o dzielony rezonator pierścieniowy (metamateriał lewoskrętny) typu SRR LHM, a następnie integrowana z opracowaną anteną w tym samym paśmie. Metamateriał umieszcza się na płaszczyźnie uziemienia anteny mikropaskowej. To odpowiednio zwiększy przepustowość. Proponowana antena metamateriałowa jest symulowana i optymalizowana za pomocą oprogramowania CST. Uzyskuje się dobrą tłumienność odbiciową większą niż 10 dB i szerokość pasma impedancji 1,04 GHz. Ta antena metamateriałowa jest dobrym kandydatem do zastosowań 5G w średnim paśmie.
10
Content available remote Sierpinski MIMO antenna for 5G applications
EN
A Sierpinski MIMO antenna was designed in the band of 3.4 – 3.8 GHz for 5G communications is demonstrated in this paper. The proposed antenna is printed on a FR_4 substrate material and dimension of the antenna was 20 × 25 × 0.8 mm3 . This paper presents the development of a compact MIMO antenna using a new structure integrated with the Sierpinski using neutralization line and defected ground structure techniques for mutual coupling reduction and antenna isolation improvement. The simulated results proved that the proposed method gives an excellent isolation performance. A good impedance matching return loss of large than 10 dB, high isolation of large than 22 dB at the operating frequency, and low ECC that was 0.026 was simulated across the coveted operating bandwidth.
PL
W artykule przedstawiono antenę Sierpińskiego MIMO, która została zaprojektowana w paśmie 3,4 - 3,8 GHz dla komunikacji 5G. Proponowana antena jest drukowana na podłożu FR_4, a wymiary anteny to 20 × 25 × 0,8 mm3. W artykule przedstawiono opracowanie kompaktowej anteny MIMO wykorzystującej nową konstrukcję zintegrowaną z anteną Sierpińskiego z wykorzystaniem linii neutralizacji oraz technik uszkodzonej struktury gruntu w celu redukcji wzajemnych sprzężeń i poprawy izolacji anteny. Symulowane wyniki dowiodły, że proponowana metoda zapewnia doskonałą izolację. W pożądanym paśmie roboczym zasymulowano dobre dopasowanie impedancji tłumienia odbicia większe niż 10 dB, wysoką izolację większą niż 22 dB przy częstotliwości roboczej i niskie ECC, które wynosiło 0,02.
11
Content available remote Pola torsyjne – przykład pseudonaukowej koncepcji w fizyce
PL
W artykule przedstawiono w zarysie założenia teorii dotyczącej pól torsyjnych traktowanych w środowisku naukowym jako element pseudonauki. Temat ten jest istotny z powodu pojawiania się teorii spiskowych związanych z wprowadzaniem nowej generacji telefonii komórkowej, będącej naturalnym rozwojem techniki oraz rozpowszechniania fałszywych informacji na temat rozprzestrzeniania się wirusów w tym Covid-19. Przedstawiona opinia autorów jest wkładem w proces edukacyjny, mający na celu eliminację teorii spiskowych ze społeczeństwa.
EN
The article outlines the assumptions of the theory of torsion fields treated in the scientific community as an element of pseudoscience. This topic is important due to the emergence of conspiracy theories related to the introduction of a new generation of mobile telephony, which is a natural development of technology, and the dissemination of false information about the spread of viruses, including Covid-19. The presented opinion of the authors is a contribution to the educational process aiming at the elimination of the conspiracy theories from the society.
12
Content available remote Fractal Vicsek MIMO antenna for LTE and 5G applications
EN
A Vicsek MIMO antenna was designed in the band of 3.3 – 4.99 GHz for both LTE and 5G communications is demonstrated in this paper. The proposed antenna is printed on a FR-4 substrate material and dimension of the antenna was 24 × 46 × 0.8 mm3 . This paper presents the development of a compact MIMO antenna using a new structure integrated with the Vicsek using neutralization line and defected ground structure techniques for mutual coupling (MC) reduction and antenna isolation improvement. The simulated results proved that the proposed method gives an excellent isolation performance. A good impedance matching return loss of large than 10 dB, high isolation of large than 16.5 dB at the operating frequency, and low envelope correlation coefficient (ECC) that was 0.0035 was simulated across the coveted operating bandwidth.
PL
W tym artykule zademonstrowano antenę Vicsek MIMO o paśmie 3,3 – 4,99 GHz dla komunikacji LTE i 5G. Proponowana antena jest wydrukowana na materiale podłoża FR-4, a jej wymiary to 24 × 46 × 0,8 mm3. W artykule przedstawiono opracowanie kompaktowej anteny MIMO z wykorzystaniem nowej struktury zintegrowanej z anteną Vicsek przy użyciu techniki linii neutralizacyjnej i uszkodzonej struktury gruntu w celu redukcji wzajemnego sprzężenia (MC) i poprawy izolacji anteny. Wyniki symulacji wykazały, że proponowana metoda zapewnia doskonałą wydajność izolacji. Zasymulowano dobrą stratę powrotną dopasowującą impedancję większą niż 10 dB, wysoką izolację większą niż 16,5 dB przy częstotliwości roboczej oraz niski współczynnik korelacji obwiedni (ECC), który wynosił 0,0035 w całej pożądanej szerokości pasma.
EN
This paper proposes a new design of a 2x2 microstrip array antenna with spiral stub for a 5G communication system at the resonant frequency of 3.5 GHz. Spiral stub is useful for increasing the bandwidth value of the proposed antenna. The spiral stub is designed using a microstrip line with an impedance of 70.7 ohms. This study proposes three antenna models by adjusting the number and dimensions of the spiral stubs. From the simulation results using EM Simulation, the optimal bandwidth is obtained when the number of spiral stubs (n) = 3 with dimensions of spiral stub Wstub =18.5 mm and Ls = 8 mm . The bandwidth of the proposed antenna is 0.8 GHz or an increase until 88.88% compared with array 2x2 without spiral stubs. Furthermore, the gain of the proposed antenna is 10.67 dB at the resonant frequency of 3.5 GHz. This research is very useful for increasing bandwidth for the purposes of 5G communication systems.
PL
W artykule zaproponowano nowy projekt anteny mikropaskowej 2x2 ze spiralnym odgałęzieniem dla systemu komunikacji 5G na częstotliwości rezonansowej 3,5 GHz. Spiralny odcinek jest przydatny do zwiększania wartości szerokości pasma proponowanej anteny. Spiralny króciec został zaprojektowany z wykorzystaniem linii mikropaskowej o impedancji 70,7 omów. W niniejszym opracowaniu zaproponowano trzy modele anten, dostosowując liczbę i wymiary końcówek spiralnych. Z wyników symulacji z wykorzystaniem symulacji EM optymalną szerokość pasma uzyskuje się, gdy liczba króćców spiralnych (n) = 3 o wymiarach króćca spiralnego Wstub =18,5 mm i Ls = 8 mm . Przepustowość proponowanej anteny wynosi 0,8 GHz lub jest wyższa o 88,88% w porównaniu z macierzą 2x2 bez spiralnych odgałęzień. Ponadto zysk proponowanej anteny wynosi 10,67 dB przy częstotliwości rezonansowej 3,5 GHz. Badania te są bardzo przydatne do zwiększania przepustowości na potrzeby systemów komunikacji 5G.
PL
O szansach i zagrożeniach, jakie niesie 5G, o możliwościach rozwoju gospodarki, rynku pracy i o tym, które z polskich miast można już zaliczyć do smart cities, mówią eksperci firmy Orange Polska - Agnieszka Zawistowska, Dyrektor ds. Rozwoju i Sprzedaży odpowiedzialna za branże Transport i Logistyka w pionie B2B oraz Artur Piecha, Dyrektor Marketingu ds. Klientów Kluczowych i Klientów Korporacyjnych.
EN
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.
EN
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.
17
EN
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.
EN
Future wireless communication networks will be largely characterized by small cell deployments, typically on the order of 200 meters of radius/cell, at most. Meanwhile, recent studies show that base stations (BS) account for about 80 to 95 % of the total network power. This simply implies that more energy will be consumed in the future wireless network since small cell means massive deployment of BS. This phenomenon makes energy-efficient (EE) control a central issue of critical consideration in the design of future wireless networks. This paper proposes and investigates (the performance of) two different energy-saving approaches namely, adaptive-sleep sectorization (AS), adaptive hybrid partitioning schemes (AH) for small cellular networks using smart antenna technique. We formulated a generic base-model for the above-mentioned schemes and applied the spatial Poisson process to reduce the system complexity and to improve flexibility in the beam angle reconfiguration of the adaptive antenna, also known as a smart antenna (SA). The SA uses the scalable algorithms to track active users in different segments/sectors of the microcell, making the proposed schemes capable of targeting specific users or groups of users in periods of sparse traffic, and capable of performing optimally when the network is highly congested. The capabilities of the proposed smart/adaptive antenna approaches can be easily adapted and integrated into the massive MIMO for future deployment. Rigorous numerical analysis at different orders of sectorization shows that among the proposed schemes, the AH strategy outperforms the AS in terms of energy saving by about 52 %. Generally, the proposed schemes have demonstrated the ability to significantly increase the power consumption efficiency of micro base stations for future generation cellular systems, over the traditional design methodologies.
19
Content available MIMO Beam Selection in 5G Using Neural Networks
EN
In this paper, we consider cell-discovery problem in 5G millimeter-wave (mmWave) communication systems using multiple input, multiple output (MIMO) beam-forming technique. Specifically, we aim at the proper beam selection method using context-awareness of the user-equipment to reduce latency in beam/cell identification. Due to high path-loss in mmWave systems, beam-forming technique is extensively used to increase Signal-to-Noise Ratio (SNR). When seeking to increase user discovery distance, narrow beam must be formed. Thus, a number of possible beam orientations and consequently time needed for the discovery increases significantly when random scanning approach is used. The idea presented here is to reduce latency by employing artificial intelligence (AI) or machine learning (ML) algorithms to guess the best beam orientation using context information from the Global Navigation Satellite System (GNSS), lidars and cameras, and use the knowledge to swiftly initiate communication with the base station. To this end, here, we propose a simple neural network to predict beam orientation from GNSS and lidar data. Results show that using only GNSS data one can get acceptable performance for practical applications. This finding can be useful for user devices with limited processing power.
EN
The world is heading towards deployment of 5G commercially by the year 2020. But providing broadband 5G connectivity to remote rural regions is a significant challenge. Fiber connectivity has attempted to penetrate rural regions but last mile connectivity is still a problem in many rural sectors due to improper land demarcation and hostile terrain. A scheme which is based on the Integrated Access and Backhaul (IAB) concept is proposed to provide last mile 5G connectivity to satisfy the broadband needs of rural subscribers. A wireless 5G downlink environment following 3GPP NR specifications with a significantly high throughput is simulated. The last mile link is provided through a 28GHz carrier from a proposed IAB node delivering a data throughput of 4.301 Gbps for single-user carrier aggregation and 5.733 Gbps for multi-user carrier aggregation which is quite promising for broadband service, like high-speed Internet and streaming video. The results presented in this work are observed to agree favourably with the results of other researchers in the field.
first rewind previous Strona / 4 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.