Electronics

Research

20 pages, 9415 KiB

Open AccessArticle

Research and Implementation of High-Efficiency and Low-Complexity LDPC Coding Algorithm

by Xiong Liao, Junxiong Guo, Zhenghua Luo, Yanghui Xu and Yingjun Chu

Electronics 2023, 12(17), 3696; https://doi.org/10.3390/electronics12173696 - 1 Sep 2023

Viewed by 1959

In this work, we proposed a high-efficiency and low-complexity encoding algorithm and its corresponding implementation structure during the design and implementation process of an LDPC encoder and decoder. This proposal was derived from extensive research on and analysis of standard encoding algorithms and [...] Read more.

In this work, we proposed a high-efficiency and low-complexity encoding algorithm and its corresponding implementation structure during the design and implementation process of an LDPC encoder and decoder. This proposal was derived from extensive research on and analysis of standard encoding algorithms and recursive iterative encoding algorithms, specifically targeting the problem of high computational complexity in encoding algorithms. Subsequently, we combined binary phase-shift keying modulation mode and additive white Gaussian noise channel transmission with the min-sum decoding algorithm to realize the (1536, 1024) LDPC codec. This codec was uniformly quantized with a (6, 2) configuration, executed eight iterations, and achieved a 2/3 code rate in the IEEE802.16e standard. At the bit error rate (BER) of

10^{- 5}

, the codec’s BER obtained by the proposed coding algorithm was about 0.25 dB lower than the recursive-iterative coding algorithm and was about 1.25 dB lower than the standard coding algorithm, which confirms the correctness, effectiveness, and feasibility of the proposed algorithm. Full article

(This article belongs to the Special Issue Wireless Communication and Multimedia Technology – Theory and Applications)

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16 pages, 4612 KiB

Open AccessArticle

Subsampling of 3D Pixel Blocks as a Video Compression Method for Analog Transmission

by Grzegorz Pastuszak

Electronics 2023, 12(12), 2641; https://doi.org/10.3390/electronics12122641 - 12 Jun 2023

Viewed by 1318

Abstract

Hybrid digital–analog transmission of video signals enables flexibility in dividing video information into two parts to utilize the available bandwidth better. This study proposes a compression scheme to reduce the utilized bandwidth. The scheme uses different subsampling in three-dimensional (3D) blocks, where subsampling [...] Read more.

Hybrid digital–analog transmission of video signals enables flexibility in dividing video information into two parts to utilize the available bandwidth better. This study proposes a compression scheme to reduce the utilized bandwidth. The scheme uses different subsampling in three-dimensional (3D) blocks, where subsampling factors are selected to minimize reconstruction distortion. The study evaluates various methods for subsampling and reconstruction to find the best combination in terms of reconstruction quality and complexity. Results show that medium-quality reconstructions can be obtained for compression ratios of about 0.125–0.3 samples per pixel. Full article

(This article belongs to the Special Issue Wireless Communication and Multimedia Technology – Theory and Applications)

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16 pages, 2676 KiB

Open AccessArticle

An Off-Nominal Class E Amplifier—Design Oriented Analysis

by Miroslaw Mikolajewski

Electronics 2023, 12(10), 2203; https://doi.org/10.3390/electronics12102203 - 12 May 2023

Cited by 1 | Viewed by 1635

Abstract

This paper analyses an off-nominal Class E ZVS amplifier, with an R.F. supply choke and the switch on-duty ratio D = 0.5, to identify conditions for its high-frequency and high-efficiency operation. Simple user-friendly analytical expressions for the essential parameters of the amplifier have [...] Read more.

This paper analyses an off-nominal Class E ZVS amplifier, with an R.F. supply choke and the switch on-duty ratio D = 0.5, to identify conditions for its high-frequency and high-efficiency operation. Simple user-friendly analytical expressions for the essential parameters of the amplifier have been derived and subsequently validated by simulation and experimental results. It has been proven that the off-nominal amplifier can be optimized to outperform the nominal Class E amplifier with respect to crucial parameters such as, e.g., power efficiency or the operating frequency in some applications. Full article

(This article belongs to the Special Issue Wireless Communication and Multimedia Technology – Theory and Applications)

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18 pages, 6604 KiB

Open AccessArticle

A Universal Hardware Platform for an LTE-Advanced Base Station Prototyping

by Przemysław Korpas, Dawid W. Rosołowski, Michał Kajczuk, Daniel Gryglewski and Wojciech Wojtasiak

Electronics 2023, 12(5), 1069; https://doi.org/10.3390/electronics12051069 - 21 Feb 2023

Cited by 1 | Viewed by 3118

Abstract

This paper presents a universal hardware platform (UHP) based on software defined radio (SDR) technology and developed to accelerate the prototyping and testing new hardware and algorithmic solutions for modern radio systems. There are two integrated transceivers and a baseband processor on the [...] Read more.

This paper presents a universal hardware platform (UHP) based on software defined radio (SDR) technology and developed to accelerate the prototyping and testing new hardware and algorithmic solutions for modern radio systems. There are two integrated transceivers and a baseband processor on the board. Thus, four complete RF transmitting and receiving channels, with observation paths for transmitted signals monitoring could be supported. Our platform can be operated in both time-division (TDD) and frequency-division (FDD) duplex schemes over a 300 MHz to 6 GHz frequency range with simultaneous synthesis and analysis in the bandwidth of up to 100 MHz. The radio system is formed by attaching an appropriate RF front-end to the UHP and uploading standard-specific software. As examples of possible UHP applications, two LTE-Advanced micro base stations for private networks with standard-defined RF front-ends operating in the LTE band B43 (3.6 GHz) with time duplex and the band B31 (450 MHz) in FDD mode are presented. Full article

(This article belongs to the Special Issue Wireless Communication and Multimedia Technology – Theory and Applications)

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20 pages, 5995 KiB

Open AccessArticle

Localization of Wireless Capsule Endoscopes Using the Receiver Selection Algorithm and a Modified Capsule Antenna

by Paweł Oleksy and Łukasz Januszkiewicz

Electronics 2023, 12(4), 784; https://doi.org/10.3390/electronics12040784 - 4 Feb 2023

Cited by 3 | Viewed by 2334

Abstract

Wireless capsule endoscopes capture and transmit images of the human gastrointestinal tract for use in medical diagnosis. The localization of the capsule makes it possible to precisely identify areas with lesions detected during the examination. The antenna is an important element of the [...] Read more.

Wireless capsule endoscopes capture and transmit images of the human gastrointestinal tract for use in medical diagnosis. The localization of the capsule makes it possible to precisely identify areas with lesions detected during the examination. The antenna is an important element of the endoscopic capsule that is used for the transmission of the signal containing the recorded image of the inside of the digestive system. Antenna parameters influence also the performance of algorithms that are locating capsule endoscopes based on the analysis of the received signal. The zig-zag conformal antenna for the endoscope capsule is presented in this paper. It was examined both in simulation and tissue simulant liquid. It is then applied to an improved localization system that is based on phase difference analysis of received signals. In this new approach, the algorithm selects five external receivers from the predefined set and uses an adaptive estimation of human body model permittivity. The localization algorithm was verified with computer simulations. Remcom XFdtd software and both simplified and heterogeneous human body models were applied in simulations. The technique which uses automatic selection of the external receiver together with proposed antenna enhanced localization accuracy by about 15% compared with the previous version of this algorithm. Full article

(This article belongs to the Special Issue Wireless Communication and Multimedia Technology – Theory and Applications)

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18 pages, 7194 KiB

Open AccessArticle

Power-Delay-Profile-Based MMSE Channel Estimations for OFDM Systems

by Sungmook Lim, Hanho Wang and Kyunbyoung Ko

Electronics 2023, 12(3), 510; https://doi.org/10.3390/electronics12030510 - 18 Jan 2023

Cited by 6 | Viewed by 3032

Abstract

This paper deals with the problem of the channel estimation of orthogonal frequency division multiplexing (OFDM) signals transmitted through a time-varying fading channel. We show that an accurate power delay profile (PDP) estimator can be obtained by utilizing the cyclic redundancy induced by [...] Read more.

This paper deals with the problem of the channel estimation of orthogonal frequency division multiplexing (OFDM) signals transmitted through a time-varying fading channel. We show that an accurate power delay profile (PDP) estimator can be obtained by utilizing the cyclic redundancy induced by a cyclic prefix (CP), which can be applicable to OFDM systems with insufficient pilot or training symbols (IEEE 802.11p/WAVE system), and then a least mean square error (MMSE) channel estimation scheme can be obtained in a manner based on the estimated PDP. The simulation results highlight the benefit of the proposed methods compared with the state-of-the-art standard and three achievable performance bounds. Full article

(This article belongs to the Special Issue Wireless Communication and Multimedia Technology – Theory and Applications)

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16 pages, 5089 KiB

Open AccessArticle

Eye Shielding against Electromagnetic Radiation: Optimal Design Using a Reduced Model of the Head

by Jarosław Kawecki, Łukasz Januszkiewicz, Paolo Di Barba and Karol Kropidłowski

Electronics 2023, 12(2), 291; https://doi.org/10.3390/electronics12020291 - 6 Jan 2023

Cited by 2 | Viewed by 3016

Abstract

This article presents the design process of a structure that shields the electromagnetic field from the fifth-generation transmitter operating in the 3.5 GHz band. The purpose of this project is the limitation of power density in the eye region. For this reason, the [...] Read more.

This article presents the design process of a structure that shields the electromagnetic field from the fifth-generation transmitter operating in the 3.5 GHz band. The purpose of this project is the limitation of power density in the eye region. For this reason, the structure is made of conducting wires forming a grid that is semitransparent to the light. The design was performed using computer simulations with a finite-difference time-domain method and an evolutionary-based optimization methodology. A simplified model of the face and eyes was developed to reduce the amount of time needed for the simulation. The construction of the shielding structure presented here can be easily fabricated in the form of protective goggles. The results of the computer simulations show that the power density in the eye region can be reduced by almost seven times compared with the unshielded case. Full article

(This article belongs to the Special Issue Wireless Communication and Multimedia Technology – Theory and Applications)

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Graphical abstract

9 pages, 1465 KiB

Open AccessCommunication

Comparison of Different Methods of Animal Detection and Recognition on Thermal Camera Images

by Łukasz Popek, Rafał Perz and Grzegorz Galiński

Electronics 2023, 12(2), 270; https://doi.org/10.3390/electronics12020270 - 5 Jan 2023

Cited by 6 | Viewed by 4115

Abstract

For most wild animals, the peak activity occurs during the night hours—their observation is possible only with the use of specialized equipment. Advancements in technology and the availability of thermal sensing devices allow researchers to examine wildlife. This study compares different methods for [...] Read more.

For most wild animals, the peak activity occurs during the night hours—their observation is possible only with the use of specialized equipment. Advancements in technology and the availability of thermal sensing devices allow researchers to examine wildlife. This study compares different methods for animal detection in thermal camera images including classical (HOG/SVM) and based on deep neural networks (Faster RCNN and YOLO). A comparison was performed to indicate the most beneficial mean Average Precision (mAP) for different levels of Intersection over Union (IoU) coverage thresholds and sensitivity (Recall). The results were evaluated on a scratch dataset containing two animal families (Cervidae and Suidae). The models were compared in terms of precision, recall, and training time. After a series of tests, the achieved performance was very satisfying: for the YOLOv3 network, the obtained mAP was above 90% for IoU > 50%; for Faster R-CNN, the obtained mAP was 87%; and for HOG/SVM, the obtained mAP was 40%. The training time for HOG/SVM was under 1 min, for YOLOv3 it was around 50 min, and for Faster R-CNN it was around 60 min. This research provides an important starting point for the creation of a ground-based system for autonomous observation of migration and population numbers, which is a unique approach in the field of wildlife research. Full article

(This article belongs to the Special Issue Wireless Communication and Multimedia Technology – Theory and Applications)

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12 pages, 1930 KiB

Open AccessCommunication

Advanced HEVC Screen Content Coding for MPEG Immersive Video

by Jarosław Samelak, Adrian Dziembowski and Dawid Mieloch

Electronics 2022, 11(23), 4040; https://doi.org/10.3390/electronics11234040 - 5 Dec 2022

Cited by 3 | Viewed by 2285

Abstract

This paper presents the modified HEVC Screen Content Coding (SCC) that was adapted to be more efficient as an internal video coding of the MPEG Immersive Video (MIV) codec. The basic, unmodified SCC is already known to be useful in such an application. [...] Read more.

This paper presents the modified HEVC Screen Content Coding (SCC) that was adapted to be more efficient as an internal video coding of the MPEG Immersive Video (MIV) codec. The basic, unmodified SCC is already known to be useful in such an application. However, in this paper, we propose three additional improvements to SCC to increase the efficiency of immersive video coding. First, we analyze using the quarter-pel accuracy in the intra block copy technique to provide a more effective search of the best candidate block to be copied in the encoding process. The second proposal is the use of tiles to allow inter-view prediction inside MIV atlases. The last proposed improvement is the addition of the MIV bitstream parser in the HEVC encoder that enables selecting the most efficient coding configuration depending on the type of currently encoded data. The experimental results show that the proposal increases the compression efficiency for natural content sequences by almost 7% and simultaneously decreases the computational time of encoding by more than 15%, making the proposal very valuable for further research on immersive video coding. Full article

(This article belongs to the Special Issue Wireless Communication and Multimedia Technology – Theory and Applications)

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