scholarly journals Modulator for implementation of amplitude modulation of many components

2021 ◽  
pp. 30-35
Author(s):  
I. V. Horbatyi ◽  
U. S. Carp ◽  
I. R. Tsymbaliuk
Keyword(s):  
Mobile Communication ◽  
Amplitude Modulation ◽  
Communication Systems ◽  
Practical Implementation ◽  
Digital Signals ◽  
Information Efficiency ◽  
Different Types ◽  
Basic Operating ◽  
Modulation Type ◽  
Digital Communication Systems

The authors consider various anti-noise techniques in systems using digital signals, in particular QAM (quadrature amplitude modulation) signals. To increase the noise immunity of a system, it is proposed to use amplitude modulation of many components (AMMС). The advantages of this approach are demonstrated. The principles of AMMС signal formation are explained. The frequency efficiency, energy efficiency, and information efficiency of such signals are theoretically calculated. Different types of digital modulation are compared, the data being presented as a table, and a conclusion is made about a possible practical implementation of the modulator for AMMC signal formation. Structural and functional diagrams of the modulator for AMMC implementation are proposed. The study formulates basic operating principles of such a device, which are used to propose a design option of the modulator. The paper describes particular aspects of creating the main units of the modulator. The authors investigate the characteristics of such a device, particularly the spectrum of the output signal. The obtained research results allow drawing a conclusion that the device complies with the formulated implementation principles of the declared modulation type. A general conclusion is made that the manufactured modulator is suitable for the AMMC. The device is proposed to be used in modern digital communication systems, such as mobile communication systems.

scholarly journals RESEARCH OF CHARACTERISTICS OF NOISE IMMUNITY WITH USE OF ORTHOGONAL CODING

2018 ◽  
pp. 80-85 ◽  
Author(s):  
A. V. Rabin ◽  
M. A. Dobroselskij ◽  
V. A. Lipatnikov
Keyword(s):  
Fading Channels ◽  
Communication Systems ◽  
Signal To Noise Ratio ◽  
Additive White Gaussian Noise ◽  
Digital Signals ◽  
Coding Gain ◽  
Convolutional Coding ◽  
Orthogonal Codes ◽  
Effective Use ◽  
Digital Communication Systems

In the digital communication systems for noise immunity's increase with the fixed code rate it is proposed to use an additional orthogonal coding developed by the authors. It is an analogue of convolutional coding over the rational numbers' field. Transmission of digital signals in Additive white Gaussian noise (AWGN) channel and fading channels is considered including a joint use of the orthogonal and correcting codes (block and convolutional). It is shown that losses in signal-to-noise ratio can be significantly reduced by use of orthogonal coding. By increase of matrices' order, on which basis orthogonal codes are constructed, the coding gain grows also. By use of the proposed by the authors orthogonal coding the required quality of communication is implemented with a smaller energy cost. The significant coding gain (up to 6,4 dB in the channels with the AWGN, up to 22,74 dB in the fading channels) provided by more effective use of energy of transmitted signals is reached without increase in complexity and cost of transmitting/receiving devices.

Simulation Implementation and Analysis of the Performance of M-QAM by Using MATLAB

2014 ◽  
Vol 610 ◽  
pp. 933-938
Author(s):  
Li Ming Yang ◽  
Jia Guo ◽  
Hong Wei Ding ◽  
Yong Wang ◽  
Hong Mei Li ◽  
...  
Keyword(s):  
Amplitude Modulation ◽  
Communication Systems ◽  
Digital Communication ◽  
Multimedia Communication ◽  
Quadrature Amplitude Modulation ◽  
Vital Role ◽  
Transmission System ◽  
Digital Multimedia ◽  
Digital Communication Systems

For the implementation of digital multimedia communication, an efficient, reliable, deterministic transmission system plays a vital role. Quadrature amplitude modulation (QAM) is commonly used in digital communication systems. We focuses on simulation and analysis of M-level QAM by using MATLAB in this paper.

scholarly journals Dual Threshold Self-Corrected Minimum Sum Algorithm for 5G LDPC Decoders

Information ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 355
Author(s):  
Rong Chen ◽  
Lan Chen
Keyword(s):  
Mobile Communication ◽  
Channel Coding ◽  
Communication Systems ◽  
Code Rate ◽  
Fifth Generation ◽  
Transmission Reliability ◽  
Average Proportion ◽  
New Generation ◽  
Digital Communication Systems ◽  
Better Than

Fifth generation (5G) is a new generation mobile communication system developed for the growing demand for mobile communication. Channel coding is an indispensable part of most modern digital communication systems, for it can improve the transmission reliability and anti-interference. In order to meet the requirements of 5G communication, a dual threshold self-corrected minimum sum (DT-SCMS) algorithm for low-density parity-check (LDPC) decoders is proposed in this paper. Besides, an architecture of LDPC decoders is designed. By setting thresholds to judge the reliability of messages, the DT-SCMS algorithm erases unreliable messages, improving the decoding performance and efficiency. Simulation results show that the performance of DT-SCMS is better than that of SCMS. When the code rate is 1/3, the performance of DT-SCMS has been improved by 0.2 dB at the bit error rate of 10 − 4 compared with SCMS. In terms of the convergence, when the code rate is 2/3, the number of iterations of DT-SCMS can be reduced by up to 20.46% compared with SCMS, and the average proportion of reduction is 18.68%.

Security Analysis of Wireless Authentication Protocols

2019 ◽  
Vol 9 (2) ◽  
pp. 247-252 ◽  
Author(s):  
Ashish Joshi ◽  
Amar Kumar Mohapatra
Keyword(s):  
Execution Time ◽  
Communication Systems ◽  
Security Analysis ◽  
Cryptographic Protocols ◽  
Command Line ◽  
Time Analysis ◽  
Authentication Protocols ◽  
Replay Attack ◽  
Peer Communication ◽  
Digital Communication Systems

Background & Objective: Cryptographic protocols had been evident method for ensuring con dentiality, Integrity and authentication in various digital communication systems. However the validation and analysis of such cryptographic protocols was limited to usage of formal mathematical models until few years back. Methods: In this paper, various popular cryptographic protocols have been studied. Some of these protocols (PAP, CHAP, and EAP) achieve security goals in peer to peer communication while others (RADIUS, DIAMETER and Kerberos) can work in multiparty environment. These protocols were validated and analysed over two popular security validation and analysis tools AVISPA and Scyther. The protocols were written according to their documentation using the HLPSL and SPDL for analysis over AVISPA and Scyther respectively. The results of these tools were analysed to nd the possible attack an each protocol. Afterwards The execution time analysis of the protocols were done by repeating the experiment for multiple iterations over the command line versions of these tools.As the literature review suggested, this research also validates that using password based protocols (PAP) is faster in terms of execution time as compared to other methods, Usage of nonces tackles the replay attack and DIAMETER is secure than RADIUS. Results and Conclusion: The results also showed us that DIAMETER is faster than RADIUS. Though Kerberos protocol was found to safe, the results tell us that it is compromisable under particular circumstances.

Code-aided adaptive equaliser for mobile communication systems

1998 ◽  
Vol 34 (17) ◽  
pp. 1638 ◽  
Author(s):  
S. Tantikovit ◽  
A.U.H. Sheikh ◽  
M.Z. Wang
Keyword(s):  
Mobile Communication ◽  
Communication Systems ◽  
Mobile Communication Systems

A Novel Automatic Modulation Classification Method Using Attention Mechanism and Hybrid Parallel Neural Network

2021 ◽  
Vol 11 (3) ◽  
pp. 1327
Author(s):  
Rui Zhang ◽  
Zhendong Yin ◽  
Zhilu Wu ◽  
Siyang Zhou
Keyword(s):  
Neural Network ◽  
Communication Systems ◽  
Parallel Structure ◽  
Modulation Classification ◽  
Automatic Modulation Classification ◽  
Spatial Features ◽  
Temporal Features ◽  
Different Types ◽  
In Series ◽  
Parallel Network

Automatic Modulation Classification (AMC) is of paramount importance in wireless communication systems. Existing methods usually adopt a single category of neural network or stack different categories of networks in series, and rarely extract different types of features simultaneously in a proper way. When it comes to the output layer, softmax function is applied for classification to expand the inter-class distance. In this paper, we propose a hybrid parallel network for the AMC problem. Our proposed method designs a hybrid parallel structure which utilizes Convolution Neural Network (CNN) and Gate Rate Unit (GRU) to extract spatial features and temporal features respectively. Instead of superposing these two categories of features directly, three different attention mechanisms are applied to assign weights for different types of features. Finally, a cosine similarity metric named Additive Margin softmax function, which can expand the inter-class distance and compress the intra-class distance simultaneously, is adopted for output. Simulation results demonstrate that the proposed method can achieve remarkable performance on an open access dataset.

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