scholarly journals Analysis of cyclic prefix length effect on ISI limitation in OFDM system over a Rayleigh-fading multipath

2021 ◽  
Vol 11 (4) ◽  
pp. 3114
Author(s):  
Sarah Zanafi ◽  
Noura Aknin
Keyword(s):  
Rayleigh Fading ◽  
Cyclic Prefix ◽  
Modulation Scheme ◽  
Transmission Channel ◽  
Ofdm System ◽  
Length Effect ◽  
Qam Modulation

<span>In this work, the influence of the cyclic prefix on the performance of the OFDM system is studied. We worked out an OFDM transceiver using a 16 QAM modulation scheme, a comparison of the BER for various lengths of the cyclic prefix has been achieved, and the influence of the noise introduced in the channel has been highlighted, for both a Gaussian and Rayleigh noise. The simulation was carried out on MATLAB where the curves of the BER for various lengths of the cyclic prefix are given and compared. We also adopted as a metric the QAM constellation to show the dispersion of the carriers as a consequence of the transmission channel, the mitigation of this effect by the CP is noticeable.</span>

scholarly journals Combined Polar Codes and 2-12 QAM over AWGN and Rayleigh Fading Channels

2021 ◽  
Author(s):  
Flávia Camila Morais Oliveira ◽  
Maria de Lourdes Melo Guedes Alcoforado ◽  
Garik Markarian ◽  
Valdemar Cardoso da Rocha Júnior
Keyword(s):  
Fading Channels ◽  
Gaussian Noise ◽  
Communication System ◽  
Rayleigh Fading ◽  
Additive White Gaussian Noise ◽  
Error Correcting Codes ◽  
Rayleigh Fading Channels ◽  
Modulation Scheme ◽  
Polar Codes ◽  
Qam Modulation

Abstract This article investigates a communication system using polar codes combined with a 2-12 QAM modulation scheme over channels disturbed by additive white Gaussian noise (AWGN) as well as over channels disturbed by Rayleigh fading in addition to AWGN. The 2-12 QAM modulation is compatible with legacy 16 QAM still widely used, and when combined with appropriate error correcting codes produces results that approach the Shannon limit.

scholarly journals Performances of BICM-ID system using CRSC code in optical transmissions

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Hocine Fekih ◽  
Boubakar Seddik Bouazza ◽  
Keltoum Nouri
Keyword(s):  
Bit Error Rate ◽  
Error Rate ◽  
Iterative Decoding ◽  
Optical Transmission ◽  
Coded Modulation ◽  
Modulation Scheme ◽  
Coding Gain ◽  
Decoding Algorithms ◽  
Qam Modulation ◽  
Short Code

AbstractRecently, using iterative decoding algorithms to achieve an interesting bit error rate for spectrally efficient modulation become a necessity for optical transmission, in this paper, we propose a coded modulation scheme based on bit interleaving circular recursive systematic convolutional (CRSC) code and 16-QAM modulation. The proposal system considered as a serial concatenation of a channel encoder, a bit interleaver and M-ary modulator can be flexible easy to implement using a short code length. For a spectral efficiency $\eta =3\text{bit}/s/Hz$, the coding gain at a bit error rate of 10−6 is about 8 dB.

Discrete framelet transform based OFDM system using N-FRAT mapping over Rayleigh fading channel

2016 ◽  
Vol 24 (3) ◽  
pp. 755-767 ◽  
Author(s):  
Suha Q. Hadi ◽  
Phaklen Ehkan ◽  
M. S. Anuar ◽  
Sameer A. Dawood
Keyword(s):  
Fading Channel ◽  
Rayleigh Fading ◽  
Rayleigh Fading Channel ◽  
Ofdm System

scholarly journals Deep neural network for orthogonal frequency division multiplexing systems without cyclic prefix transmission

2018 ◽  
Vol 189 ◽  
pp. 04016
Author(s):  
Viet-Hung Nguyen ◽  
Minh-Tuan Nguyen ◽  
Yong-Hwa Kim
Keyword(s):  
Neural Network ◽  
Orthogonal Frequency Division Multiplexing ◽  
Deep Neural Network ◽  
Cyclic Prefix ◽  
Wireless Transmission ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Ofdm System ◽  
New Approach ◽  
Multiplexing Systems

Orthogonal frequency division multiplexing (OFDM) is widely used in wired or wireless transmission systems. In the structure of OFDM, a cycle prefix (CP) has been exploited to avoid the effects of inter-symbol interference (ISI) and inter-carrier interference (ICI). This paper proposes a new approach to transmit the signals without CP transmission. Using the deep neural network, the proposed OFDM system transmits data without the CP. Simulation results show that the proposed scheme can estimate the CP at the receiver and overcome the effect of ISI.

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