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.

scholarly journals DEVELOPMENT OF A CLASS OF SYSTEM AND RETURN SYSTEM MATRIXES PROVIDING INCREASE IN NOISE IMMUNITY OF SPECTRALLY EFFECTIVE MODULATION SCHEMES ON BASIS OF ORTHOGONAL CODING

2018 ◽  
pp. 75-79 ◽  
Author(s):  
A. V. Rabin ◽  
S. V. Michurin ◽  
V. A. Lipatnikov
Keyword(s):  
Signal To Noise Ratio ◽  
Inverse System ◽  
System Matrix ◽  
Synthesis Algorithm ◽  
Convolutional Coding ◽  
Integer Coefficients ◽  
Orthogonal Codes ◽  
Definition Of ◽  
Effective Use ◽  
Special Case

In work it is proposed in the digital systems of messages transmission for noise immunity's increase with the fixed code rate to use an additional coding called by the authors orthogonal. The way of a definition of orthogonal codes is presented, the synthesis algorithm of system and inverse system matrices of orthogonal codes is developed, and the main parameters of some matrices constructed by the offered algorithm are specified. Orthogonal coding as a special case of convolutional coding is defined by matrices, which elements are polynomials in the delay variable with integer coefficients. Code words are given by multiplication of an information polynomial by a system matrix, and decoding is performed by multiplication by an inverse system matrix. Basic ratios for orthogonal coding are given in article, and properties of system and inverse matrices are specified. Parameters of system and inverse system matrices assure additional gain in signal-to-noise ratio. This gain is got as a result of a more effective use of energy of transmitted signals. For transmission of one symbol energy of several symbols is accumulated.

Performance Analysis of Digital Communication Systems Over $\alpha$ -$\kappa$ -$\mu$ Fading Channels

2019 ◽  
Vol 23 (1) ◽  
pp. 192-195 ◽  
Author(s):  
Jules M. Moualeu ◽  
Daniel B. da Costa ◽  
Walaa Hamouda ◽  
Ugo S. Dias ◽  
Rausley A. A. de Souza
Keyword(s):  
Performance Analysis ◽  
Fading Channels ◽  
Communication Systems ◽  
Digital Communication ◽  
Digital Communication Systems

scholarly journals PERFORMANCE OF NETWORK CODING SCHEMES FOR 5G SYSTEM

2021 ◽  
Vol 4 (2) ◽  
pp. 1-8
Author(s):  
Shurooq M. Abdulkhudhur ◽  
Abdulkareem A. Kadhim
Keyword(s):  
Network Coding ◽  
Fading Channels ◽  
Error Rate ◽  
Communication Systems ◽  
Additive White Gaussian Noise ◽  
Packet Error Rate ◽  
Main Task ◽  
Error Performance ◽  
Coding Schemes ◽  
Communication Links

Huge data rates have been provided by 5G wireless communication systems using millimeter wave (mmWave) band that have frequencies ranging from 30 to 300 GHz.  mmWave provides much wider bandwidth than the existing 4G band.  The 5G network deals with massive number of devices.  This presents many challenges including capacity, end to end delay, data rate, and very large number of connections.  In this paper, the main task is to apply network coding to 5G mmWave communication system to increase the throughput of the communication links.  Simple packet-based network coding schemes using butterfly network topology are simulated.  The two network coding schemes considered here are Physical Layer Network Coding (PLNC) and Network Layer Network Coding (NLNC).   Models of Additive White Gaussian Noise (AWGN) and mmWave indoor fading channels are considered in the work using Quadrature Phase Shift Keying (QPSK) modulation. The results of the tests showed that the use of both NLNC and PLNC improved throughput in comparison to uncoded system.  Using PLNC increased the Bit Error Rate (BER) and the Packet Error Rate (PER), while NLNC scheme showed almost identical error performance to uncoded system over mmWave fading channel.  The results show that network coding improved throughput when compared.

scholarly journals A Review for the Adopted Techniques in Low SNR Communication Systems

2020 ◽  
pp. 40-52
Keyword(s):  
Low Power ◽  
Fading Channels ◽  
Communication Systems ◽  
Noise Power ◽  
Analysis And Design ◽  
Low Snr ◽  
Successful Communication ◽  
Unified Study ◽  
Energy Trade ◽  
Digital Communication Systems

The study and evaluation of digital communication systems in low signal-to-noise power ratio (LSNR) environments is a hot and important topic due to its wide contemporary applications. This review is an attempt to focus on the most distinctive vital parameters required in the analysis and design of such systems. It includes a brief literature survey for many algorithms, techniques, methodologies, and mitigations that have been used to overcome the high noise problem encountered in these systems in order to guarantee reliable communication. Amongst these topics, the study reviews the most widely utilized modulation techniques in LSNR communication systems such as the On-Off Keying (OOK) and binary PSK schemes. The capacity for both AWGN and wireless fading channels is also discussed along with a clarification of the minimum limits in these types of channels. On the other hand, some important and recommended detection and estimation techniques for low power communication systems are briefly covered. This unified study has additionally discussed spectral efficiency and bit energy trade-off within the low-power, and broadband systems, and different limitations are stated clearly. Finally, the survey throughout this paper recommends some significant techniques that can be used in the analysis and design of successful communication systems in LSNR regimes.

scholarly journals Encrypted message transmission in a QO-STBC encoded MISO wireless Communication system under implementation of low complexity ML decoding algorithm

2012 ◽  
Vol 2 (2) ◽  
pp. 53-58
Author(s):  
Shaikh Enayet Ullah ◽  
Md. Golam Rashed ◽  
Most. Farjana Sharmin
Keyword(s):  
Fading Channels ◽  
Gaussian Noise ◽  
Communication System ◽  
Channel Coding ◽  
Signal To Noise Ratio ◽  
Additive White Gaussian Noise ◽  
Text Message ◽  
Low Complexity ◽  
White Gaussian Noise ◽  
Message Transmission

In this paper, we made a comprehensive BER simulation study of a quasi- orthogonal space time block encoded (QO-STBC) multiple-input single output(MISO) system. The communication system under investigation has incorporated four digital modulations (QPSK, QAM, 16PSK and 16QAM) over an Additative White Gaussian Noise (AWGN) and Raleigh fading channels for three transmit and one receive antennas. In its FEC channel coding section, three schemes such as Cyclic, Reed-Solomon and ½-rated convolutionally encoding have been used. Under implementation of merely low complexity ML decoding based channel estimation and RSA cryptographic encoding /decoding algorithms, it is observable from conducted simulation test on encrypted text message transmission that the communication system with QAM digital modulation and ½-rated convolutionally encoding techniques is highly effective to combat inherent interferences under Raleigh fading and additive white Gaussian noise (AWGN) channels. It is also noticeable from the study that the retrieving performance of the communication system degrades with the lowering of the signal to noise ratio (SNR) and increasing in order of modulation.

scholarly journals PERFORMANCE EVALUATION OF RELAYING SCHEMES FOR WIRELESS COMMUNICATION SYSTEMS

2013 ◽  
pp. 157-161
Author(s):  
MANISHA CRASTO BRAGANC ◽  
HASANALI G. VIRANI ◽  
SHAILESH KHANOLKAR
Keyword(s):  
Communication Systems ◽  
Signal To Noise Ratio ◽  
Additive White Gaussian Noise ◽  
Multiple Input Multiple Output ◽  
Amplify And Forward ◽  
Decode And Forward ◽  
Wireless System ◽  
Single Input Single Output ◽  
Single Output ◽  
Alamouti Coding

The evaluation of MIMO (multiple-input multiple-output) Relay wireless system is carried out and compared against the performance of a SISO (single-input single-output) Relay wireless system. The encoding scheme used in MIMO is Alamouti coding and decoding is done by the Maximum Likelihood (ML) detector. A comparison is made between the SISO non-regenerative amplify-and-forward (AF) and regenerative decode-and-forward (DF) relaying schemes. The plots of bit error rate (BER) versus signal to noise ratio (SNR) are simulated by incorporating Rayleigh fading condition in the presence of additive white Gaussian noise(AWGN) using MATLAB.

scholarly journals Building a noise-tolerant code based on a holographic representation of arbi-trary digital information

2020 ◽  
Vol 44 (6) ◽  
pp. 978-984
Author(s):  
A.L. Timofeev ◽  
A.Kh. Sultanov
Keyword(s):  
Communication Systems ◽  
Noise Immunity ◽  
Multipath Propagation ◽  
Signal To Noise Ratio ◽  
Additive White Gaussian Noise ◽  
Digital Signal ◽  
Code Word ◽  
Virtual Space ◽  
Digital Information ◽  
Radio Communications

The article considers a method of error-correcting coding based on the holographic representation of a digital signal. The message encoding process is a mathematical simulation of a hologram created in virtual space by a wave from an input signal source. The code word is a hologram of a point, it is also a one-dimensional zone ruler that carries information about the input data block in the form of an n-bit code of the coordinate of the center of the Fresnel zones. It is shown that the holographic representation of the signal has significantly greater noise immunity and allows you to restore the original digital combination when most of the code message is lost and when the encoded signal is distorted by noise several times higher than the signal level. To assess the noise immunity, the reliability of information transmission over the channel with additive white Gaussian noise is compared using the Reed-Solomon code, the Reed-Muller code, the majority code, and the holographic code. The comparative efficiency of codes in the presence of packet errors caused by the effect of fading due to multipath propagation in radio channels is considered. It is shown that holographic coding provides the correction of packet errors regardless of the length of the packet and its location in the codeword. The holographic code is of interest for transmitting information over channels with a low signal-to-noise ratio (space communications and optical communication systems using free space as a transmission channel, terrestrial, including mobile radio communications), as well as for storing information in systems exposed to ionizing radiation.

An efficient adaptive modulation technique over realistic wireless communication channels based on distance and SINR

Frequenz ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Rahim Khan ◽  
Qiang Yang ◽  
Alam Noor ◽  
Sohaib Bin Altaf Khattak ◽  
Liang Guo ◽  
...  
Keyword(s):  
Wireless Communication ◽  
Fading Channels ◽  
Communication Systems ◽  
Additive White Gaussian Noise ◽  
Adaptive Modulation ◽  
Base Stations ◽  
Rician Fading ◽  
Available Bandwidth ◽  
Modulation Schemes ◽  
The Impact

Abstract A growing trend has been observed in recent research in wireless communication systems. However, several limitations still exist, such as packet loss, limited bandwidth and inefficient use of available bandwidth that needs further investigation and research. In light of the above limitations, this paper uses adaptive modulation under various parameters, such as signal to interference plus noise ratio (SINR), and communication channel’s distances. The primary goal is to minimize bit error rate (BER), improve throughput and utilize the available bandwidth efficiently. Additionally, the impact of Additive White Gaussian Noise (AWGN), Rayleigh and Rician fading channels on the performance of various modulation schemes are also studied. The simulation results demonstrate that our proposed technique optimally improves the BER and spectral efficiency in the long-range communication as compared to the fixed modulation schemes under the co-channel interference of surrounding base stations. The results indicate that the performance of fixed modulation schemes is suitable only either at high SINR and low distance or at low SINR and high distance values. Moreover, on the other hand, its performance was suboptimal in the entire wireless communication channel due to high distortion and attenuation. Lastly, we also noted that BER performance in the AWGN channel is better than Rayleigh and Rician channels with Rayleigh channel exhibiting poor performance than the Rician channel.

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