scholarly journals Reduction of the Multipath Propagation Effect in a Hydroacoustic Channel Using Filtration in Cepstrum

Sensors ◽  
2020 ◽  
Vol 20 (3) ◽  
pp. 751 ◽  
Author(s):  
Agnieszka Czapiewska ◽  
Andrzej Luksza ◽  
Ryszard Studanski ◽  
Andrzej Zak

During data transmission in a hydroacoustic channel, one of the problems is the multipath propagation effect, which leads to a decrease in the transmission parameters and sometimes completely prevents it. Therefore, we have attempted to develop a method, which is based on a recorded hydroacoustic signal, that allows us to recreate the original (generated) signal by eliminating the multipath effect. In our method, we use cepstral analysis to eliminate replicas of the generated signal. The method has been tested in simulation and during measurements in a real environment. Additionally, the influence of the method on data transmission in the hydroacoustic channel was tested. The obtained results confirmed the usefulness of the application of the developed method and improved the quality of data transmission by reducing the multipath propagation effect.

Sensors ◽  
2020 ◽  
Vol 20 (24) ◽  
pp. 7255
Author(s):  
Agnieszka Czapiewska ◽  
Andrzej Luksza ◽  
Ryszard Studanski ◽  
Andrzej Zak

When transmitting data in a hydroacoustic channel under difficult propagation conditions, one of the problems is intersymbol interference (ISI) caused mainly by the effect of multipath propagation. This phenomenon leads to a decrease in transmission parameters, and sometimes completely prevents it. Therefore, we have made an attempt to use diversity combining with Recursive Least Squares (RLS) adaptive filtering to improve the quality of data transmission in a hydroacoustic channel with strong reflections. The method was tested in simulation and during measurements in a real environment. The influence of the method on data transmission in the hydroacoustic channel was examined in detail. The obtained results allow us to draw conclusions regarding the purposefulness of use of diversity combining and RLS adaptive filtering in order to improve the quality of data transmission by reducing the effect of ISI.


Author(s):  
 M.S. MUTHANNA ◽  
A.S. MUTHANNA ◽  
 A.S. BORODIN

Achieving high Quality of Service (QoS) remains a challenge for LoRa technology. However, high QoS can be achieved via optimizing the transmission policy parameters such as bandwidth and code rate. Existing approaches do not provide an opportunity to optimize the LoRa networks' data transmission parameters. The article proposes transmission policy enforcementfor QoS-aware LoRanetworks.The QoSparameter ranking is implemented for IoT nodes where priority and nonpriority information is identified by the new field of LoRa frame structure(QRank).The optimaltransmissionpolicyenforcement uses fast deep reinforcement learning that utilizes the environmental parameters including QRank, signal quality, and signal-to-interference-plus-noise-ratio. The transmission policy is optimized for spreading factor, code rate, bandwidth, and carrier frequency. Performance evaluation is implemented using an NS3.26 LoRaWAN module. The performance is examined for various metrics such as delay and throughput. Достижение высокого качества обслуживания (QoS) по-прежнему остается достаточно сложной задачей для технологии LoRa. В принципе высокий уровень QoS может быть достигнут за счет оптимизации параметров передачи, например, пропускной способности и скорости передачи информации в сети. Известные на сегодняшний день решения не дают возможности оптимизировать параметры передачи данных для сетей LoRa. В статье предложен эффективный метод передачи данных, обеспечивающий требования по QoS при использовании технологии LoRa. Ранжирование параметров QoS для узлов интернета вещей определяется новым полем структуры фрейма LoRa (QRank) для приоритетной и неприоритетной информации. Для обеспечения эффективной передачи применяется быстрое глубокое обучение с подкреплением, для которого используются как параметры качества обслуживания, так и отношение сигнал/шум. Метод передачи оптимизирован с учетом коэффициента распространения, скорости передачи данных, полосы пропускания и несущей частоты. Оценка производительности при применении предложенного метода проведена с использованием модуля LoRaWAN в пакете имитационного моделирования NS3.26. Производительность оценивается на основе параметров задержки и пропускной способности.


Author(s):  
Fani Rakhman Hakim ◽  
Bambang Sugiantoro

The technology of internet nowadays has become most important aspect and becomes primary need for certain group of peoples who work in some field like education,economy,health,etc. One of the biggest problem which mostly brought by so many people is speed in data transfer. This paper emphasize in directly testing the quality of data transmission from each transmission technology. The equipment used by this paper is ZTE Join Air help, the simcard provided by Telkomsel,XL, and indosat, while CDMA technology used simcard provided by smartfren and esia and modem provided by Smartfren which its series is EC176-2. The parameters used for testing in this paper are throughput, time, jitter dan packet loss. this paper used data gathering method, for each operator and the testing used by this paper is downloading some files from local and non local server, then comparing parameter value between operators.


2021 ◽  
Vol 2021 (2) ◽  
pp. 229-241
Author(s):  
Vera L. LUKICHEVA ◽  
◽  
Andrey A. PRIVALOV ◽  
Daniil D. TITOV ◽  
◽  
...  

Objective: To analyze the impact of computer attacks on the performance quality of data transmission channels and channeling systems. It is also necessary to take into account the capabilities of an intruder to introduce malware into channeling systems when committing a computer attack. Methods: To determine the required design ratios, several options for setting various distribution functions characterizing the parameters used as input data and types of inbound streams have been considered, taking into account the parameters of the intruder’s computer attack model set by the values of the probability of successful attack. Mathematical modeling is carried out using the method of topological transformation of stochastic networks. The exponential, momentum and gamma distributions are considered as distribution functions of random variables. The solutions are presented for inbound streams corresponding to the Poisson, Weibull, and Pareto models. Results: The proposed approach makes it possible to assess the performance quality of data transmission channels in the context of computer attacks. These assessments make it possible to analyze the state and develop guidelines for improving the performance quality of communication channels against the destructive information impact of the intruder. Various variants of the functions of random variables distribution and various types of the inbound stream were used for modeling, making it possible to compare them, as well as to assess the possibility of using them in channels that provide users with different services. Practical importance: The modeling results can be used to build communication management decision support systems, as well as to detect attempts of unauthorized access to the telecommunications resource of transportation management systems. The proposed approach can be applied in the development of threat models to describe the capabilities of the intruder (the ‘Intruder Model’).


2011 ◽  
Vol 225-226 ◽  
pp. 194-198
Author(s):  
Yan Zhang ◽  
Wen Yu Yu

For the unsymmetrical bandwidth in HFC network, this paper proposes a data transmission scheme of Cable Modem based on DOCSIS1.1. This scheme can meet different kinds of data’s demands. It can guarantee fine grading data transmission management and low ratio of packet loss. Then, this paper proves the validity of the scheme. Lastly, in order to improve the quality of data transmission, it gives the difficulties and research perspective in the future.


2021 ◽  
Vol 24 (4) ◽  
pp. 73-79
Author(s):  
Kirill Eduardovich Korepanov ◽  
Irina Alekseevna Kaisina ◽  
Roman Eduardovich Shibanov ◽  
Albert Vinerovich Abilov ◽  
Mohammed Amin Lamri

The paper presents the results of simulation of the process of video data transmission from an unmanned aerial vehicle (UAV) to a ground station using the IEEE 802.11 family standards (802.11n, 802.11ac and 802.11ax), with the ability to change modulation indices, coding schemes and data transfer rate in a network simulator NS-3. The aim of the work is to analyze the characteristics of the quality of video data transmission in the UAV network for various Wi-Fi standards, which allows determining the most suitable standard for the transmission of video data in the UAV network, depending on the distances between nodes and the required frequency band. A scenario is considered in which an unmanned aerial vehicle (UAV) hovering in the air was transmitting a video stream to a ground station, while the distance between nodes increased, and the transmission rate was maintained at the same level close to the transmission rate of the real video stream. The simulation was carried out in several stages for a more detailed study of the dependence of the packet loss of the transmitted data on the change in modulation indices, coding schemes and other parameters. Based on the simulation results, the characteristics of the video data transmission quality were obtained as a relation between the Packet delivery rate (PDR) and distance between nodes for different transmission parameters for each considered standard of the IEEE 802.11 family. Based on the results obtained, conclusions were drawn about the influence of transmission parameters on the quality of service characteristics. The study was carried out in an open-source network simulator NS-3, which implements build-in libraries that are necessary for high-quality simulation of data streaming transmission and allows you to set a wide range of parameters to obtain realistic results. The results of the work may be of interest to UAV manufacturers when planning missions in which the choice of Wi-Fi standard used as a channel for transmitting video data is crucial.


1993 ◽  
Vol 8 (1) ◽  
pp. 57-66 ◽  
Author(s):  
Bruce A. Houtchens ◽  
Terry P. Clemmer ◽  
Harry C. Holloway ◽  
Alexander A. Kiselev ◽  
James S. Logan ◽  
...  

AbstractIntroduction:The Telemedicine Spacebridge, a satellite-mediated, audio-video-fax link between four United States and two Armenian and Russian medical centers, permitted remote American consultants to assist Armenian and Russian physicians in the management of medical problems following the December 1988 earthquake in Armenia and the June 1989 gas explosion near Ufa.Methods:During 12 weeks of operations, 247 Armenian and Russian and 175 American medical professionals participated in 34 half-day clinical conferences. A total of 209 patients were discussed, requiring expertise in 20 specialty areas.Results:Telemedicine consultations resulted in altered diagnoses for 54, new diagnostic studies for 70, altered diagnostic processes for 47 and modified treatment plans for 47 of 185 Armenian patients presented. Simultaneous participation of several US medical centers was judged beneficial; quality of data transmission was judged excellent.Conclusion:These results suggest that interactive consultation by remote specialists can provide valuable assistance to on-site physicians and favorably influence clinical decisions in the aftermath of major disasters.


Author(s):  
M. B. Ibrahim ◽  
K. A. Gbolagade

Data size minimization is the focus of data compression procedures by altering representation and reducing redundancy of information to a more effective kind. In general, lossless approach is favoured by a number of compression methods for the purpose of maintaining the content integrity of the file afterwards. The benefits of compression include saving storage space, speed up of data transmission and high quality of data. This paper observes the effectiveness of Chinese Remainder Theorem (CRT) enhancement in the implementation of Lempel-Ziv-Welch (LZW) and Huffman coding algorithms for the purpose of compressing large size images. Ten images of Yale database was used for testing. The outcomes revealed that CRT-LZW compression saved more space and speedy compression (or redundancy removal) of original images to CRT-Huffman coding by 29.78% to 14.00% respectively. In terms of compression time, CRT-LZW approach outperformed CRT-Huffman approach by 9.95 sec. to 19.15 sec. For compression ratio, CRT-LZW also outperformed CRT-Huffman coding by 0.39 db to 4.38 db, which is connected to low quality and imperceptibility of the former. Similarly, CRT-Huffman coding (28.13db) offered better quality Peak-Signal-to-Noise-Ratio (PSNR) for the reconstructed images when compared to CRT-LZW (3.54db) and (25.59db) obtained in other investigated paper.


2021 ◽  
Vol 2094 (3) ◽  
pp. 032067
Author(s):  
P O Vinar ◽  
S V Rabin ◽  
A V Rabin

Abstract The method of the synthesis of circulant polynomial matrices for the implementation of the operation of code combining of channels on the transmitting side of the communication system has been developed. The structure of these matrices is the basis for reducing the complexity of encoder schemes and, consequently, the radiated power of radio transmitters of subscriber devices. The research results can be applied in communication systems with multiple access, with a wide coverage area, high quality of data transmission, high noise immunity, stability of communication channels from interception and eavesdropping.


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