scholarly journals Optimum Frequency Allocation Mechanism of TV White Spaces by using Interval Graph

2019 ◽  
Vol 9 (1S5) ◽  
pp. 107-111
Keyword(s):  
Communication Systems ◽  
Interval Graph ◽  
Wireless Communication Systems ◽  
Optimum Number ◽  
User Requirements ◽  
Allocation Mechanism ◽  
Optimum Frequency ◽  
Data Rates ◽  
The One ◽  
The Given

The unused frequencies of terrestrial TV are being explored in the recent years, to satisfy the bandwidth demands of ever-increasing wireless communication systems. Allocating these unused TV frequencies is often a challenging task. Allocations that fulfil the user requirements at various instants, while maximizing the utilization of available TV frequencies is the one that is desired. In this paper, interval-graph method is implemented to identify the optimum number of channels needed for the given demand of bandwidths. Simulations are carried out by using GLPK 4.65 solver. Results show the appropriate number of channels required or conversely the reduction of data rates to individual users based on the available bandwidths.

scholarly journals Propagation Channel Measurements in the mm- and Sub-mm Wave Range for Different Indoor Communication Scenarios

2021 ◽  
Vol 42 (4) ◽  
pp. 357-370
Author(s):  
M. A. Salhi ◽  
T. Kleine-Ostmann ◽  
T. Schrader
Keyword(s):  
Wireless Communication ◽  
Communication Systems ◽  
Wireless Communication Systems ◽  
Electromagnetic Spectrum ◽  
Channel Measurements ◽  
Frequency Range ◽  
Propagation Channel ◽  
Data Rates ◽  
Indoor Wireless ◽  
Wave Range

AbstractIncreasing data rates in wireless communications are accompanied with the need for new unoccupied and unregulated bandwidth in the electromagnetic spectrum. Higher carrier frequencies in the lower THz frequency range might offer the solution for future indoor wireless communication systems with data rates of 100 Gbit/s and beyond that cannot be located elsewhere. In this review, we discuss propagation channel measurements in an extremely broad frequency range from 50 to 325 GHz in selected indoor communication scenarios including kiosk downloading, office room communication, living rooms, and typical industrial environments.

scholarly journals Active textile antennas in professional garments for sensing, localisation and communication

2014 ◽  
Vol 6 (3-4) ◽  
pp. 331-341 ◽  
Author(s):  
Arnaut Dierck ◽  
Sam Agneessens ◽  
Frederick Declercq ◽  
Bart Spinnewyn ◽  
Gert-Jan Stockman ◽  
...  
Keyword(s):  
Communication Systems ◽  
Noise Figure ◽  
The Body ◽  
Wireless Communication Systems ◽  
Energy Harvesters ◽  
Textile Antenna ◽  
Design Paradigm ◽  
The One ◽  
Processing Techniques ◽  
High Degree

New wireless wearable monitoring systems integrated in professional garments require a high degree of reliability and autonomy. Active textile antenna systems may serve as platforms for body-centric sensing, localisation, and wireless communication systems, in the meanwhile being comfortable and invisible to the wearer. We present a new dedicated comprehensive design paradigm and combine this with adapted signal-processing techniques that greatly enhance the robustness and the autonomy of these systems. On the one hand, the large amount of real estate available in professional rescue worker garments may be exploited to deploy multiple textile antennas. On the other hand, the size of each radiator may be designed large enough to ensure high radiation efficiency when deployed on the body. This antenna area is then reused by placing active electronics directly underneath and energy harvesters directly on top of the antenna patch. We illustrate this design paradigm by means of recent textile antenna prototypes integrated in professional garments, providing sensing, positioning, and communication capabilities. In particular, a novel wearable active Galileo E1-band antenna is presented and fully characterized, including noise figure, and linearity performance.

scholarly journals Joint Channel Estimation and Synchronization Techniques for Time-Interleaved Block-Windowed Burst OFDM

2021 ◽  
Vol 11 (10) ◽  
pp. 4403
Author(s):  
João Martins ◽  
Filipe Conceição ◽  
Marco Gomes ◽  
Vitor Silva ◽  
Rui Dinis
Keyword(s):  
Channel Estimation ◽  
Communication Systems ◽  
Power Efficiency ◽  
Frame Synchronization ◽  
Frequency Domain Multiplexing ◽  
Training Sequences ◽  
Data Rates ◽  
The One ◽  
Time Interleaved ◽  
Joint Channel

From a conceptual perspective, beyond-5G technologies promise to deliver very low latency, even higher data rates, and ultrareliable connections for future generations of communication systems. Modulation schemes based on orthogonal frequency-domain multiplexing (OFDM) can accommodate these requirements for wireless systems. Several hybrid OFDM-based systems, such as the time-interleaved block-windowed burst–OFDM (TIBWB–OFDM), are capable of achieving even better spectral confinement and power efficiency. This paper addresses the implementation of the TIBWB–OFDM system in more realistic and practical wireless link scenarios by addressing the challenges of proper and reliable channel estimation and frame synchronization. We propose to incorporate a preamble formed by optimal correlation training sequences such as the Zadoff–Chu (ZC) sequences. The added ZC preamble sequence is used to jointly estimate the frame beginning through signal-correlation strategies and a threshold decision device, and acquire channel-state information (CSI) by employing estimators on the basis of the preamble sequence and transmitted data. The employed receiver estimators show that it is possible to detect the TIBWB–OFDM frame beginning and highlight the robustness of the TIBWB–OFDM technique to imperfect channel estimations by showing that it can provide comparatively close BER performance to the one where the CSI is perfectly known.

Federated Learning and Control at the Wireless Network Edge

2021 ◽  
Vol 24 (3) ◽  
pp. 9-13
Author(s):  
Mehdi Bennis
Keyword(s):  
Machine Learning ◽  
Communication Systems ◽  
Wireless Communication Systems ◽  
Low Latency ◽  
Decision Making Under Uncertainty ◽  
Significant Progress ◽  
Sensors And Actuators ◽  
Fifth Generation ◽  
The One ◽  
And Control

We are at the cusp of two transformational technologies, namely the fifth generation of wireless communication systems, known as 5G, and machine learning (ML). On the one hand, while the evolutionary part of 5G, enhanced mobile broadband (eMBB), focusing mainly on millimeter-wave transmissions has made significant progress, fundamentals of ultra-reliable and low-latency communication (URLLC), one of the major tenets of the 5G revolution, are yet to be fully understood. In essence, URLLC warrants a departure from average-based system design toward a clean slate design centered on tail, risk, and scale [1]. While risk is encountered when dealing with decision making under uncertainty, scale is driven by the sheer amount of devices, antennas, sensors, and actuators, all of which pose unprecedented challenges in network design, optimization, and scalability.

scholarly journals Digital Predistortion (DPD) Algorithm For 5G Applications

2021 ◽  
Author(s):  
S.G. SHIVAPRASAD YADAV ◽  
MEGHANA .
Keyword(s):  
Power Amplifier ◽  
Communication Systems ◽  
Wireless Communication Systems ◽  
Rf Power Amplifiers ◽  
Digital Predistortion ◽  
Fifth Generation ◽  
Wideband Signals ◽  
Data Rates ◽  
Linear Power Amplifier ◽  
Memory Polynomial

Abstract The wireless networks of upcoming fifth generation (5G) promises connection speeds and data rates that are one hundred times faster than the existing networks and much improved signal and connection quality. As there is the development of wireless communication systems, the requirement of Power Amplifier’s linearity is hard. The Radio Frequency (RF) power amplifiers that are operating with wideband signals such as WCDMA that is used in UMTS leads to the generation of out-of-band emissions which are referred as “Spectral regrowth”. To improve PA efficiency and linearity, this paper uses Digital Predistortion technique. This paper of DPD in combination with power amplifier using Memory Polynomial Algorithm is designed in the MATLAB/SIMULINK. The designed algorithm was tested with against various test cases and it was observed with high non-linearity and the good performance is seen for the order of 4 and 5 of the memory polynomial and non-linearity coefficients having linear output. Hence by using Memory Polynomial DPD in this paper the output of the previous input and present input is obtained. The advantage of DPD is having a linear power amplifier with less distortion and high non-linearity.

Efficient Receiver Implementation for Mobile Applications

2009 ◽  
pp. 271-298
Author(s):  
Costas Chaikalis ◽  
Felip Riera-Palou
Keyword(s):  
Communication Systems ◽  
Low Complexity ◽  
Wireless Communication Systems ◽  
Channel Decoding ◽  
High Data ◽  
Data Rates ◽  
Channel Effects ◽  
Environment Simulation ◽  
Very High

Modern and future wireless communication systems such as UMTS and beyond 3G systems (B3G) are expected to support very high data rates to/from mobile users. This poses important challenges on the handset design as they should be able to attain an acceptable operating bit error rate (BER) while employing a limited set of resources (i.e. low complexity, low power) and often, with tight processing delay constraints. In this chapter we study how channel decoding and equalisation, two widely used mechanisms to combat the deleterious channel effects, can be made adaptable in accordance to the instantaneous operating environment. Simulation results are given demonstrating how receiver reconfigurability is a promising method to achieve complexity/delay efficient receivers while maintaining prescribed quality of service (QoS) constraints.

scholarly journals Relay-assisted WDM-FSO System: A Better Solution for Communication under Rain and Haze Weather Conditions

2017 ◽  
Vol 4 ◽  
pp. 54-59
Author(s):  
Navneet Dayal ◽  
Preeti Singh ◽  
Pardeep Kaur
Keyword(s):  
Wavelength Division Multiplexing ◽  
Electromagnetic Interference ◽  
Communication Systems ◽  
Weather Conditions ◽  
Wireless Communication Systems ◽  
Wavelength Division ◽  
High Data ◽  
Space Optics ◽  
System A ◽  
Data Rates

Among various conventional wireless communication systems, Free Space Optics (FSO) may be distinguished as well, which provides a good level security, high data rates, an enormous bandwidth and negligible susceptibility to electromagnetic interference. The main problem arises with unfavorable weather conditions, which affect the system’s parameters and require an aversion to other paths. The weather conditions discussed are rain and haze. Elimination of their adverse effects is essential for establishing a better communication system. The routing path is a major issue, as its decreased parameters lead to the diversion of the transmitted signal or to its total loss. In this article, increased system path length and proficiency levels are demonstrated by using relays, which are assisted by Wavelength Division Multiplexing (WDM).

THE EU SUGAR MARKET PROFILE AND ITS MAIN DRIVERS

2015 ◽  
Author(s):  
Lubos SMUTKA ◽  
Irena BENEŠOVÁ ◽  
Patrik ROVNÝ ◽  
Renata MATYSIK-PEJAS
Keyword(s):  
Market Failure ◽  
Current System ◽  
Quota System ◽  
Considerable Debate ◽  
Sugar Market ◽  
The Common ◽  
The One ◽  
Production Capacities ◽  
The Given ◽  
The Eu

Sugar is one of the most important elements in human nutrition. The Common Market Organisation for sugar has been a subject of considerable debate since its establishment in 1968. The European agricultural market has been criticized for its heavy regulations and subsidization. The sugar market is one of the most regulated ones; however, this will change radically in 2017 when the current system of production quotas will end. The current EU sugar market changed is structure during the last several decades. The significant number of companies left the market and EU internal sugar market became more concentrated. The aim of this paper is presentation characteristics of sugar market with respect to the supposed market failure – reduction in competition. The analysis also identifies the main drivers and determinants of the EU especially quota sugar market. In relation to paper’s aim the following results are important. The present conditions of the European sugar market have led to market failure when nearly 75 % (10 million tonnes) of the quota is controlled by five multinational companies only. These multinational alliances (especially German and French one) are also taking control over the production capacities of their subsidiaries. In most countries, this causes serious problems as the given quota is controlled by one or two producers only. This is a significant indicator of market imperfection. The quota system cannot overcome the problem of production quotas on the one hand and the demand on the other; furthermore, it also leads to economic inefficiency. The current EU sugar market is under the control of only Sudzucker, Nordzucker, Pfeifer and Langen, Tereos and ABF.

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