scholarly journals Research on LDPC in an OFDM System

2021 ◽  
Vol 2078 (1) ◽  
pp. 012075
Author(s):  
Chong-Yue Shi ◽  
Hui Li ◽  
You-Ling zhou ◽  
Ping Wang ◽  
Qian Li ◽  
...  
Keyword(s):  
Fading Channel ◽  
Rayleigh Fading ◽  
Simulation Analysis ◽  
Ldpc Codes ◽  
Ldpc Code ◽  
Rayleigh Fading Channel ◽  
Code Length ◽  
Ofdm System ◽  
Number Of Iterations ◽  
Better Than

Abstract In this paper, LDPC codes and OFDM technologies are studied, and combines LDPC and OFDM to simulate and verify the performance. The encoding of LDPC and logarithmic domain BP decoding algorithm and the principle of OFDM are introduced. Through MATLAB, the simulation of OFDM-LDPC system in different channel, different code length, different iteration times, LDPC and OFDM-LDPC in the same conditions are compared. Through simulation analysis, we can know that the performance of OFDM-LDPC system will improve with the increase of the code length. When the SNR is small, the number of iterations has little effect on the performance of OFDM-LDPC system. When the SNR is large, the performance of the system will be improved with the increase of the number of iterations. The performance of OFDM-LDPC codes is better than that of LDPC codes. The performance of OFDM-LDPC code is better than LDPC code in multipath Rayleigh fading channel.

Research on Parallel Convolutional LDPC Code Based on Random Interleaver

2013 ◽  
Vol 427-429 ◽  
pp. 1510-1513
Author(s):  
Ce Lun Liu ◽  
Xu Su ◽  
Long Bo Han ◽  
Xiao Jie Wen
Keyword(s):  
Gaussian Noise ◽  
Fading Channel ◽  
Rayleigh Fading ◽  
Ldpc Code ◽  
Rayleigh Fading Channel ◽  
Encoding Method ◽  
Number Of Iterations ◽  
Ber Performance

Starting from pseudo-random interleaver and parallel convolution respectively, this paper has proposed a simple and fast LDPC encoding method without the loss of BER performance. when we use S-random interleaver, it has a good adaptation in both Gaussian noise channel and Rayleigh fading channel. And it can conduct random pre-encoding directly and does not need to look up for 4-cycles. Even if the number of iterations is low, its performance also remains stable.

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 Carrier Frequency Offset Effects on OFDM System over Rayleigh Fading Channel

2020 ◽  
Vol 3 (2) ◽  
pp. 45
Author(s):  
N. M. A. E. Dewi Wirastuti ◽  
I.G.A.K. Diafari Djuni Hartawan ◽  
I Made Arsa Suyadnya ◽  
Duman Care Khrisne
Keyword(s):  
Fourier Transform ◽  
Fading Channel ◽  
Orthogonal Frequency Division Multiplexing ◽  
Rayleigh Fading ◽  
Carrier Frequency Offset ◽  
Rayleigh Fading Channel ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Ofdm System ◽  
Modulation And Demodulation

Orthogonal Frequency Division Multiplexing (OFDM) system showed the use of Discrete Fourier Transform (DFT) and Inverse Discrete Fourier Transform (IDFT) to perform the baseband modulation and demodulation. So that, it can increase and improve the efficiency of the modulation and demodulation. Currently, the OFDM is being utilized in the field of broadband wireless communication, which transmit signals orthogonally, that increases speed of information transmission. It also has high proficiency with high bandwidth and provide large data rates and robust against the multipath delay spread. On the other hand, there are some issues faced OFDM system which are high Peak Average Power Ratio (PAPR), and sensitive to Phase Noise (PN) and Carrier Frequency Offset (CFO). This paper presents Orthogonal Frequency Division Multiplexing (OFDM) performance evaluation in the presence of CFO with two different environment scenarios were used: an AWGN channel and a Rayleigh fading channel. The simulation was performed to evaluate the effects of CFO based on Bit Error Rate (BER) vs. Energy Bit per Noise Ratio (Eb/No). The results showed that for BER degradation caused by CFO effects have presented in our simulation for both AWGN and Rayleigh fading channel.

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