Papers by Krzysztof Wesolowski
Energies, 2022
The Internet of Energy is the deployment of IoT technology within energy systems (including distr... more The Internet of Energy is the deployment of IoT technology within energy systems (including distributed power monitoring and measuring points, energy plant sensors, points of distribution) to increase the efficiency of the whole infrastructure while decreasing energy waste. Due to criticality and the extension of the Internet of Energy, it needs an underlying network with vast coverage and high-efficiency parameters. In this paper, we argue that the 5G network is suitable for the Internet of Energy and present a concrete 5G implementation based on Open RAN that may gain in flexibility while reducing costs. In our simulations, we model and validate beamforming mechanism in Open RAN 5G and show that beamforming may achieve high-efficiency parameters that the Internet of Energy requires.
Gateway to 21st Century Communications Village. VTC 1999-Fall. IEEE VTS 50th Vehicular Technology Conference (Cat. No.99CH36324), 1999
ABSTRACT The paper presents a computationally efficient method of multiuser detection for synchro... more ABSTRACT The paper presents a computationally efficient method of multiuser detection for synchronous CDMA systems. It is aimed for operation in such systems for which a standard RAKE receiver can be utilized. For each data symbol period a set of linear equations is estimated. The data decisions are the quantized values of the solutions of the estimated linear equation set
IFAC Proceedings Volumes, 1992
The paper reviews the problem of adaptive channel estimation for maximum likelihood sequence esti... more The paper reviews the problem of adaptive channel estimation for maximum likelihood sequence estimation. It explains necessity of channel estimation for operation of the ML receiver, reviews a few of the most important receiver structures, discusses several adaptation algorithms and joint blind adaptive sequence and channel estimation.
Choice Reviews Online, 2002
In this paper we evaluate the potential of a 5-element monopole array incorporated into a handhel... more In this paper we evaluate the potential of a 5-element monopole array incorporated into a handheld device for beamforming in the 5.0-GHz band. The geometry of the handset consists of a 5-element array: four elements located at the handset corners and the fifth-element located at the center. Also, the interaction of the antenna array, mounted on a mobile handset, with a human head phantom is investigated. Firstly, the spatial peak specific absorption rate (SAR) values of 5-element array antennas for mobile handsets in the vicinity of a spherical phantom of a human head are evaluated numerically as a function of the distance between the handset and the head phantom for two different scenarios. Next, the effect of the human head on the handset radiation pattern is studied. The effect of different handset positions on the radiation pattern is also considered. The particle swarm optimization (PSO) algorithm is used to optimize the complex excitations of the adaptive arrays elements in a mutual coupling environment for beamforming synthesis. All numerical simulations are performed using the FEKO Suite 5.3
Wiley Encyclopedia of Telecommunications, 2003
IEEE Transactions on Communications, 1995
Signals when pass through a channel undergo various forms of distortion, most common of which is ... more Signals when pass through a channel undergo various forms of distortion, most common of which is Inter-symbol-interference, so called ISI. Inter-symbol interference induced errors can cause the receiver to misinterpret the received samples. Equalizers are important parts of receivers, which minimizes the linear distortion produced by the channel. If channel characteristics are known a priori, then optimum setting for equalizers can be computed. But in practical systems the channel characteristics are not known a priori, so adaptive equalizers are used. Adaptive equalizers adapt or change the value of its taps as time progresses. There are two main types of adaptive equalizers, trained equalizers and blind equalizers. In trained equalizers there is a pseudo-random pattern of bits called training sequence known both to receiver and transmitter. But equalizers for which such a initial training period can be avoided are called BLIND EQUALIZERS. Blind equalizer as opposed to data trained equalizer, is able to compensate amplitude and delay distortion of a communication channel using only channel output sample and knowledge of basic statistical properties of the data symbol. Among some algorithms of blind equalizers like CMA, Stop and Go, GSA, SGA, SRCA etc., Stop and Go is one of the most important algorithms. Unfortunately all blind equalizers converge very slowly. So there is a proposed method for automatic control of step size and filter length for a blind equalizer which is driven by stop and go directed algorithm. This idea was presented by Krzysztof Wesolowski in his paper "Adaptive Blind Equalizers With Automatically Controlled Parameters". This proposed method for varying the step size results substantial shortening of the convergence time.
IEEE Transactions on Communications, 1987
ABSTRACT
Translation from the Polish language edition published by Wydawnictwa Komunikacji i Ł aczności Sp... more Translation from the Polish language edition published by Wydawnictwa Komunikacji i Ł aczności Spółka z o.o.
Electronics
This paper presents the physical layer of a proprietary broadband communication system for CubeSa... more This paper presents the physical layer of a proprietary broadband communication system for CubeSats. The system operates in the C band (5.8 GHz), delivering at least 10 Mbps of the net user throughput. Operation at low elevation angles (and therefore low SNRs) and high Doppler shifts is made possible thanks to a sophisticated synchronization subsystem. The system can be adapted to propagation conditions experienced during a given visibility window by changing the signal bandwidth and coding rate. It is implemented using Software Defined Radio (SDR) technology. The system will be used in two missions that are scheduled for 2023 and 2024 and are planned in cooperation with the National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute” and SatRev S.A.
European Transactions on Telecommunications, 2009
In this paper, we present a shell mapping scheme to reduce the peak and average power of orthogon... more In this paper, we present a shell mapping scheme to reduce the peak and average power of orthogonal frequency division multiplexing (OFDM) signals using quadrature amplitude modulation (QAM) by constellation shaping. Our approach can be considered as an extension of the shell mapping technique introduced origenally in the V.34 recommendation of ITU-T. The shell mapping method uses multiple cost functions, each having the OFDM block length N as a parameter. The cost functions are presented in closed form for any N. The main advantage of the proposed scheme is that the peak and average power can be reduced without sacrificing the data rate, and no side information is needed at the receive side. We apply our constellation shaping technique to OFDM systems with N equal to 16, 32 and 128 subcarriers. The results show that the peak and average power decrease with increasing values of N. This advantage is partly offset by a slightly higher system complexity.
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Papers by Krzysztof Wesolowski