scholarly journals BER PERFORMANCE ANALYSIS OF 4QAM/OFDM OVER DIFFERENT SCENARIOS OF LAPLACE FADING CHANNEL.

2021 ◽  
Vol 25 (Special) ◽  
pp. 1-26-1-33
Author(s):  
Hassan F. Mohammed ◽  
◽  
Ghanim A. Al-Rubaye ◽  
Keyword(s):  
Fading Channels ◽  
Fading Channel ◽  
Orthogonal Frequency Division Multiplexing ◽  
High Speed ◽  
Additive White Gaussian Noise ◽  
Multipath Fading ◽  
Local Area ◽  
Ofdm System ◽  
Multicarrier Transmission ◽  
Simulation Results

Multicarrier transmission, also known as (OFDM) Orthogonal Frequency Division multiplexing, in wireless communications, it has been proven to be an essential technique for countering multipath fading. It has been used successfully for HF radio applications and has been selected as the interface for digital audio transmission, digital terrestrial TV broadcasting, and high-speed wireless local area networks in Europe. In this paper, we suggested a new design for modeling multipath fading channels, such as the Laplace fading channel, in order to discover new simulation results and effects. Furthermore, the variance of the Laplace fading channel has been computed and the new Bit Error Rate (BER) derivation is established, and the performance of (M-QAM), M-ary Quadrature Amplitude Modulation (with M=4 over OFDM system under Laplace fading channels in Additive White Gaussian Noise (AWGN) is discussed and compared to the conventional M-QAM/OFDM system Rayleigh fading channel in AWGN. All the simulation results are examined using the optimum signal detection based on the Euclidean distance and evaluated using Monte-Carlo simulation.

scholarly journals EFFICIENT ANALYSIS OF MIMO-OFDM SYSTEM IN NAKAGAMI-m FADING CHANNEL

2016 ◽  
Vol 54 (6) ◽  
pp. 698
Author(s):  
Ho Van Cuu ◽  
Hoang Hiep Le ◽  
Nguyen Thi Thu-Hang
Keyword(s):  
Phase Shift ◽  
Fading Channels ◽  
Error Rate ◽  
Fading Channel ◽  
Orthogonal Frequency Division Multiplexing ◽  
Multipath Fading ◽  
Phase Shift Keying ◽  
Ofdm System ◽  
Shift Keying ◽  
Mimo Ofdm

Bit error rate (BER) and symbol error rate (SER) performance response fading parameter for multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) system over Nakagami-m fading channel would be provided in this study. Some channel simulations and evaluations were for 2×2 MIMO-OFDM system in which data are sent from two transmit antennas to two receive antennas. In this study, authors have used binary phase-shift keying (BPSK) and quadrature phase-shift keying (QPSK) modulation techniques to modulate the data stream. In addition, numerical results have been presented and compared for several different environmental propagations such as Nakagami-m, Rician, Rayleigh multipath fading channels, and non-fading additive white Gaussian noise (AWGN) channel. Based on such obtained presentation and comparison, the paper would discuss further about relation between value of paramater m and quality of system.

scholarly journals A Radon Slantlet Transforms Based OFDM System Design and Performance Simulation under Different Channel Conditions

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Abbas Hasan Kattoush
Keyword(s):  
Radon Transform ◽  
Spectral Efficiency ◽  
Fading Channel ◽  
Orthogonal Frequency Division Multiplexing ◽  
Additive White Gaussian Noise ◽  
Mapping Technique ◽  
Intercarrier Interference ◽  
Ofdm Systems ◽  
Ofdm System ◽  
Channel Parameters

Due to its good orthogonality, slantlet transform (SLT) is used in orthogonal frequency division multiplexing (OFDM) systems to reduce intersymbol interference (ISI) and intercarrier interference (ICI). This eliminates the need for cyclic prefix (CP) and increases the spectral efficiency of the design. Finite Radon transform (FRAT) mapper has the ability to increase orthogonality of subcarriers, is nonsensitive to channel parameters variations, and has a small constellation energy compared with conventional fast-Fourier-transform- (FFT-) based OFDM. It is also able to work as a good interleaver, which significantly reduces the bit error rate (BER). In this paper both FRAT mapping technique and SLT modulator are implemented in a new design of an OFDM system. The new structure was tested and compared with conventional FFT-based OFDM, Radon transform-based OFDM, and SLT-based OFDM for additive white Gaussian noise (AWGN) channel, flat fading channel (FFC), and multipath selective fading channel (SFC). Simulation tests were generated for different channel parameters values. The obtained results showed that the proposed system has increased the spectral efficiency, reduced ISI and ICI, and improved BER performance compared with other systems.

PERFORMANCE OF QAM-OFDM SYSTEM OVER RAYLEIGH FADING CHANNEL IN WEI BULL NOISE DISTRIBUTION

2021 ◽  
Vol 25 (Special) ◽  
pp. 1-157-1-166
Author(s):  
Nabaa I. Abed ◽  
◽  
Ghanim A.AL Rubaye ◽  
Keyword(s):  
Fading Channels ◽  
Communication Networks ◽  
Orthogonal Frequency Division Multiplexing ◽  
Rayleigh Fading ◽  
Additive White Gaussian Noise ◽  
Wireless Networking ◽  
Ofdm System ◽  
Exact Match ◽  
Communication Industry ◽  
Non Gaussian

The phenomenal increase in the usage of mobile devices and wireless networking tools in recent years has resulted in the communication industry needing higher data speeds for connections and bandwidth. As a result, multi-carrier modulation has been suggested as a reliable and effective method of transmitting data over difficult communication networks such as selective fading channels. Orthogonal Frequency Division Multiplexing (OFDM) is a highly effective multi-carrier technique that can meet users' high demands. Many studies have looked into this technique, mostly as a way to counteract fading and Additive White Gaussian Noise (AWGN). As a result, the performance evaluation of the QAM-OFDM system in the presence of multi-path Rayleigh fading in Weibull noise is examined in this article. Furthermore, bit error rate performance (BER) is computed using the optimal derivation of the real system contaminated by compound Gaussian and non-Gaussian (Weibull) noise distributions at the OFDM demodulator output. The derived result is an exact match to the simulated result over various scenarios introduced by the MATLAB software package.

scholarly journals PAPR reduction in OFDM system for DVB-S2

2020 ◽  
Vol 17 (1) ◽  
pp. 317
Author(s):  
Zainab M Abid ◽  
Awatif A Jaffaar ◽  
Suha Q Hadi
Keyword(s):  
Fading Channels ◽  
Power Amplifier ◽  
Spectral Efficiency ◽  
Orthogonal Frequency Division Multiplexing ◽  
High Speed ◽  
Average Power ◽  
Multipath Fading ◽  
Papr Reduction ◽  
Major Drawback ◽  
Ofdm Signal

<p>A special form of multicarrier modulation is Orthogonal Frequency Division Multiplexing (OFDM) which is offer high spectral efficiency for high speed data transmission through multipath fading channels. Many advantages can be achieved by using OFDM in addition to spectral efficiency like its robustness against intersymbol interference and multipath effect. One of a major drawback of OFDM is high Peak-to-Average Power Ratio (PAPR) of the transmitted signal which leads to a distortion in the power amplifier and causes decreasing the efficiency of power amplifier. To reduce PAPR of OFDM signal many of promising solutions have been proposed and implemented. In this paper, a joint Low Density Parity Check code (LDPC), Discrete Cosine Transform (DCT) and μ-law companding is proposed to reduce PAPR of OFDM signal at transmitter. Comparison of these PAPR reduction techniques is done based on CCDF performance of the system.</p>

Joint Channel Estimation and Signal Detection for the OFDM System Without Cyclic Prefix Over Doubly-Selective Channels

2015 ◽  
Vol 25 (14) ◽  
pp. 1540028
Author(s):  
Lijun Song ◽  
Xia Lei ◽  
Maozhu Jin ◽  
Zhihan Lv
Keyword(s):  
Channel Estimation ◽  
Signal Detection ◽  
Fading Channels ◽  
Orthogonal Frequency Division Multiplexing ◽  
High Speed ◽  
Detection Algorithm ◽  
Cyclic Prefix ◽  
Fast Time ◽  
Ofdm System ◽  
Joint Channel

In the high-speed railway wireless communication, a joint channel estimation and signal detection algorithm is proposed for the orthogonal frequency division multiplexing (OFDM) system without cyclic prefix in the doubly-selective fading channels. Our proposed method first combines the basis expansion model (BEM) and the inter symbol interference (ISI) cancellation to overcome the situation that exists with the fast time-varying channel and the normalized maximum multipath channel exceeding the length of the cyclic prefix (CP). At first, the channel estimation and signal detection can be approximated without considering the ISI. Then, the channel parameters and signal detection are updated through ISI cancellation and circular convolution reconstruction from the frequency domain. The simulations show the algorithm can improve the performance of channel estimation and signal detection.

scholarly journals Performance of OFDM System under Different Fading Channels and Channel Coding

2017 ◽  
Vol 6 (1) ◽  
pp. 54-61
Author(s):  
Pratima Manhas ◽  
M. K. Soni
Keyword(s):  
Fading Channels ◽  
Channel Coding ◽  
Orthogonal Frequency Division Multiplexing ◽  
Mobile Station ◽  
Multipath Fading ◽  
Ofdm System ◽  
Angle Of Arrival ◽  
Multiple Reflections ◽  
Multipath Fading Channels ◽  
Base Transceiver Station

Orthogonal frequency division multiplexing (OFDM) is a type of multicarrier modulation (MCM) technique in which larger bandwidth is divided into parallel narrow bands each of which is modulated by different subcarriers. All the subcarriers are orthogonal to each other and hence it reduces the interference among various subcarriers. OFDM technique is an efficient modulation technique used in certain wired and wireless application.In a wireless communication channel, the transmitted signal can travel from transmitter to receiver over multiple reflective paths. This results to multipath fading which causes fluctuations in amplitude, phase and angle of arrival of the received signal. For example, the signal which is transmitted from BTS (base transceiver station) may suffer multiple reflections from the buildings nearby, before reaching the mobile station. Such multipath fading channels are classified into slow fading/fast fading and frequency-selective/flat fading channels. This paper discusses the performance of OFDM system using various fading channels and channel coding. The parameter which is known as Bit error rate (BER) is calculated under different fading channels (AWGN, Rayleigh and Rician) for different digital modulation (BPSK, QPSK and QAM) and Channel coding (linear/Cyclic coding). Matlab Simulink tool is used to calculate the BER parameter.

OFDM System Performance Evaluation under Different Fading Channels and Channel Coding using Matlab Simulink

2017 ◽  
Vol 5 (2) ◽  
pp. 260
Author(s):  
Pratima Manhas ◽  
M.K Soni
Keyword(s):  
Fading Channels ◽  
Channel Coding ◽  
Orthogonal Frequency Division Multiplexing ◽  
Mobile Station ◽  
Multipath Fading ◽  
Ofdm System ◽  
Multiple Reflections ◽  
Matlab Simulink ◽  
Base Transceiver Station ◽  
Wireless Application

<p>Orthogonal Frequency Division Multiplexing (OFDM) is a form of Multicarrier Modulation (MCM) technique in which larger bandwidth is divided into parallel narrow bands each of which is modulated by different subcarriers. All the subcarriers are orthogonal to each other and hence it reduces the interference among various subcarriers. OFDM technique is an efficient modulation technique used in certain wired and wireless application. During transmission, the transmitted signal can travel from transmitter to receiver over multiple reflective paths in case of wireless communication system which results to multipath fading and produces variation in amplitude, phase and angle of the received signal. The signal which is transmitted from BTS (base transceiver station) may undergo multiple reflections from the buildings nearby, before reaching the mobile station. This paper discusses the performance of OFDM system using various fading channels and channel coding. The parameter which is known as Bit error rate (BER) is calculated for different fading channels (AWGN, Rayleigh and Rician) for different digital modulation (BPSK, QPSK and QAM) and Channel coding(linear/ Cyclic coding).The tool which is used to evaluate  the BER parameter is Matlab Simulink.</p>

scholarly journals A Novel GFDM Waveform Design Based on Cascaded WHT-LWT Transform for the Beyond 5G Wireless Communications

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1831
Author(s):  
Meryem Maraş ◽  
Elif Nur Ayvaz ◽  
Meltem Gömeç ◽  
Asuman Savaşcıhabeş ◽  
Ali Özen
Keyword(s):  
Fading Channels ◽  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
Additive White Gaussian Noise ◽  
Average Power ◽  
Hadamard Transform ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Simulation Results ◽  
Walsh Hadamard Transform

In this paper, a new WHT-LWT-GFDM waveform obtained by combining Walsh–Hadamard Transform (WHT), Lifting Wavelet Transform (LWT), and Generalized Frequency Division Multiplexing (GFDM) is presented for use in next-generation wireless communication systems. The proposed approach meets the requirement of 5th-generation (5G) and beyond communication schemes in terms of low latency, low peak-to-average-power ratio (PAPR), and low bit-error rate (BER). To verify the performance of the presented waveform, PAPR and BER simulation results were obtained in additive white Gaussian noise (AWGN) and flat Rayleigh fading channels, and the performance of the proposed system was compared with conventional Orthogonal Frequency Division Multiplexing (OFDM), GFDM, and Walsh–Hadamard transform-based GFDM (WHT-GFDM). Simulation results show that the proposed waveform achieves the best BER and PAPR performances and it provides considerable performance gains over the conventional waveforms.

scholarly journals Indoor optical wireless MIMO-OFDM system

2014 ◽  
Vol 17 (1) ◽  
pp. 5-16
Author(s):  
Khoa Le Dang ◽  
Tung Thanh Vu ◽  
Tu Thanh Nguyen ◽  
Phuong Huu Nguyen
Keyword(s):  
Fading Channels ◽  
Electromagnetic Interference ◽  
Orthogonal Frequency Division Multiplexing ◽  
High Speed ◽  
Optical Wireless ◽  
Error Vector Magnitude ◽  
Ofdm System ◽  
High Data ◽  
Mimo Ofdm ◽  
Vector Magnitude

Indoor optical wireless systems have attracted attention, because they allow high-speed transmission without electromagnetic interference. Multi Input Multi Output (MIMO) techniques are very promising in providing high data rate or providing performance over fading channels. Orthogonal frequency division multiplexing (OFDM) can send multiple high speed signals by using orthogonal carrier frequencies. In this paper, we propose an optical wireless MIMO-OFDM system to achieve better performance. The signal of each optical transmit antenna is detected by using zero forcing (ZF) algorithm. We use the error vector magnitude (EVM) to predict BER performance. The analysis of bit error rate (BER) shows that the proposed system achieve better performance transmission than OMIMO system when transmitting the signal over reflection channels.

Comparison of various channel equalization techniques in OFDM system using different digital modulations

2016 ◽  
Vol 3 (3) ◽  
pp. 634 ◽  
Author(s):  
Pratima Manhas ◽  
M.K. Soni
Keyword(s):  
Fading Channels ◽  
Orthogonal Frequency Division Multiplexing ◽  
Signal To Noise Ratio ◽  
Multipath Fading ◽  
Ofdm System ◽  
Multipath Fading Channels ◽  
Estimation Algorithms ◽  
High Data ◽  
Data Rates ◽  
High Data Rates

<p>The nature of future wireless applications requires high data rates and for this OFDM technique is used. OFDM stands for orthogonal frequency division multiplexing and is a type of multi-carrier transmission where all the subcarriers are orthogonal to each other. At high data rates, the channel distortion to the data is very important and it is somewhat impossible to recover the transmitted data with a simple receiver. So a complex receiver structure is needed which uses computationally expensive equalization and channel estimation algorithms to estimate the channel. These estimations can be used within the received data to recover the originally transmitted data. OFDM can simplify the equalization problem by changing the frequency-selective channel into a flat channel. The radio channels in mobile radio systems are usually multipath fading channels that results in intersymbol interference (ISI) in the received signal. To remove ISI from the signal, many kind of equalizers can be used. The need for equalizers arises from the fact that the channel has amplitude and phase dispersion which results in the interference of the transmitted signals with one another which is known as ISI .So, to solve this problem equalizers are designed. Equalizer is intend to work in such a way that Bit Error Rate (BER) should be low and Signal-to-Noise Ratio (SNR) should be high. An equalizer within a receiver compensates for the average range of expected channel amplitude and delay characteristics. This paper deals with the various equalization techniques (LMS, RLS and CMA) used for OFDM system .A comparative analysis of different equalization technique in terms of BER is done using MATLAB Simulink.</p>

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