Simulative Effect of Cyclic Prefix in Optical OFDM

2014 ◽  
Vol 661 ◽  
pp. 190-194
Author(s):  
A.O. Aldhaibani ◽  
S.A. Aljunid ◽  
Mohd Shamsul Anuar ◽  
A.R. Arief ◽  
H.Y. Ahmed
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Signal To Noise Ratio ◽  
Transmission Efficiency ◽  
Cyclic Prefix ◽  
Frequency Division ◽  
Interference Effects ◽  
Ofdm System ◽  
Guard Interval ◽  
Optical Ofdm ◽  
Simulation Results

Orthogonal frequency division multiplexing (OFDM) is one of the Multi-Carrier Modulation (MCM) techniques that transmit signals through multiple carriers. These carriers (subcarriers) have different frequencies and they are orthogonal to each other. There are different parameters which alter the performance of OFDM system. In this paper, the effect of cyclic prefix length (CP) on optical (OFDM) system is investigated. Although employing a CP as the guard interval is a simple way to combat inter-symbol interference (ISI) and inter-carrier interference (ICI), it reduces the transmission efficiency of the system. The simulation results show the effect of CP length in power receiver, penalty of power and improved the performance based on signal to noise ratio (SNR). In addition, a tradeoff is needed between reduced interference effects and transmission efficiency.

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.

scholarly journals A CCM-Based OFDM System with Low PAPR for Sparse Source

2018 ◽  
Vol 2018 ◽  
pp. 1-7
Author(s):  
Qinbiao Yang ◽  
Zulin Wang ◽  
Qin Huang
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Average Power ◽  
Coded Modulation ◽  
High Peak ◽  
Frequency Division Multiplexing ◽  
Power Ratio ◽  
Frequency Division ◽  
Ofdm System ◽  
Simulation Results ◽  
Clipping And Filtering

Orthogonal frequency division multiplexing (OFDM) usually suffers high peak-to-average power ratio (PAPR). As shown in this paper, PAPR becomes even severe for sparse source due to many identical nonzero frequency OFDM symbols. Thus, this paper introduces compressive coded modulation (CCM) in order to restrain PAPR by reducing identical nonzero frequency symbols for sparse source. As a result, the proposed CCM-based OFDM system, together with iterative clipping and filtering, can efficiently restrain the high PAPR for sparse source. Simulation results show that it outperforms about 4 dB over the traditional OFDM system when source sparsity is 0.1.

scholarly journals BER performance study for optical OFDM of optical camera communication

2021 ◽  
Vol 11 (5) ◽  
pp. 4263
Author(s):  
Noor J. Jihad ◽  
Sinan M. Abdul Satar
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Signal To Noise Ratio ◽  
Frequency Division ◽  
Performance Study ◽  
Mapping Rule ◽  
Bit Loading ◽  
Dc Bias ◽  
Optical Ofdm ◽  
Ber Performance ◽  
Optical Camera Communication

In this article, different forms of optical orthogonal frequency division multiplexing (OFDM) were observed which were suitable for optical camera communication (OCC) systems. This research aims to establish the bit error rate (BER) versus signal-to-noise ratio (SNR) of the OCC system. This research will focus on OCC systems and the design that produces the noise of the clipping but will gain SNR as a whole if an optimum clipping factor is chosen. The BER versus SNR analysis was investigated for the different clipping factors 0.7, 1.4, and 2.6. The BER performance of the asymmetrically clipped optical OFDM (ACO-OFDM) was also compared with the direct current optical OFDM (DCO-OFDM) to show the suitable effectiveness of the proposed approach. ACO-OFDM was considered to be better due to lower bit loading, but DCO-OFDM was efficient for higher SNR values. This was because the DC bias used was inefficient in terms of optical capacity, while ACO-OFDM used only half of the subcarriers to transmit the information. Moreover, ACO-OFDM two-dimensional half-subcarriers of mapping rule would introduce the clipping noise to its unused 2D subcarriers, although further data can be provided by the 2D DCO-OFDM mapping rule.

The Study of Interpolation Algorithms in OFDM Systems

2013 ◽  
Vol 321-324 ◽  
pp. 2837-2840
Author(s):  
Xi Jun Zhang ◽  
Jian Bin Xue ◽  
Ying Lin ◽  
Ji Ai He
Keyword(s):  
Channel Estimation ◽  
Orthogonal Frequency Division Multiplexing ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Ofdm Systems ◽  
Ofdm System ◽  
Simulation Process ◽  
Interpolation Algorithms ◽  
Simulation Results

Orthogonal frequency division multiplexing (OFDM) is a kind of highly transmission technology. It has been taken more and more attention in many ways. In this paper it mainly discussed the simulation process and several interpolation algorithms in OFDM system. Using computer we simulate the interpolation algorithms in OFDM channel estimation. Through the simulation results we compare the advantage and disadvantage of the interpolation algorithms. At last we can use the conclusion to choose the correct interpolation algorithms in OFDM channel estimation.

scholarly journals Real-Time Mitigation of the Mobility Effect for IEEE 802.15.4g SUN MR-OFDM

2019 ◽  
Vol 9 (16) ◽  
pp. 3289 ◽  
Author(s):  
Huy Nguyen ◽  
Nam Tuan Le ◽  
Nguyen Cong Hoan ◽  
Yeong Min Jang
Keyword(s):  
Low Power ◽  
Real Time ◽  
Doppler Shift ◽  
Orthogonal Frequency Division Multiplexing ◽  
Cyclic Prefix ◽  
Wide Area ◽  
Wide Area Networks ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Ofdm System

In order to develop wireless sensor networks, which are defined by the IEEE 802.15.4 specification, researchers are considering low-power wide-area networks (LPWAN) due to their advantages of being long range, low power, low cost, and highly mobile. The issue of mobility is covered in the IEEE 802.15.4g standard for supporting a smart utility network (SUN), which is mainly controlled by orthogonal frequency-division multiplexing (OFDM) modulation. In a high mobility scenario, inter-carrier interference is a primary factor in reducing the performance of OFDM transmissions due to the destruction of the subcarrier component’s orthogonality. This paper analyzes the mobility effect in multi-rate multi-regional orthogonal frequency-division multiplexing (MR-OFDM) for low-power wide-area networks in general, and the SUN MR-OFDM system in particular. As mentioned in standard 802.15.4 2015, IEEE 802.15.4g MR-OFDM is one of the low-power wide-area (LPWA) technologies in which energy optimization problems are of first priority. We are especially interested in simple technologies that provide high efficiency. Therefore, we propose a highly adaptive method that uses the cyclic prefix to mitigate the mobility effect in real time. At a symbol frames interval of 120 us, the Doppler shift effect from the mobility of the MR-OFDM system adapted smoothly. This is not the best method to mitigate Doppler shift but it is a simple method that suits the LPWA network. The proposed scheme clearly simulated the mobility of the MR-OFDM system, and had the advantage of using a cyclic-prefix with a bit error rate performance through Additive White Gaussian Noise (AWGN) and the Rician channel of Matlab.

scholarly journals Performance on FBMC-OQAM and OFDM Multicarrier Systems

2019 ◽  
Vol 8 (10) ◽  
pp. 1564-1568
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Filter Bank ◽  
Signal To Noise Ratio ◽  
Cyclic Prefix ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Signal To Noise ◽  
Multicarrier Systems ◽  
Noise Ratio ◽  
Power Equality

Filter Bank Multi Carrier (FBMC) offers best detestable properties took a gander at over orthogonal frequency division multiplexing (OFDM) to the attack of nonexistent hindrance. FBMC system is a multicarrier structure, particularly sensible for 5G remote correspondences. FBMC beats OFDM as a result of proficient use of the open information move limit and without usage of cyclic prefix (CP). In this paper, we address the issue of remarkable enrollment at the pilot territory and used to audit the channels with pilot picture, in like way consider the fundamental conditions for utilization of the assistant pilot pictures. First and two partner pictures for each pilot plans with power equality uses instead of one picture; it can attainable inspirations driving necessity of OFDM and FBMC depending upon signal to noise ratio (SNR) what's relentlessly possible to improve the introduction of one frivolity pictures by using multiple associate pictures. Finally autonomous the BER execution reenactment results and adornment pilot pictures

scholarly journals Model Kanal 5G dengan Pengaruh Kelembapan pada Frekuensi 3,3 GHz dan Bandwidth 99 MHz Berbasis Convolutional Codes

2021 ◽  
Vol 9 (4) ◽  
pp. 878
Author(s):  
RENI DYAH WAHYUNINGRUM ◽  
KHOIRUN NI’AMAH ◽  
SOLICHAH LARASATI
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Channel Model ◽  
Signal To Noise Ratio ◽  
Convolutional Codes ◽  
Cyclic Prefix ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Signal To Noise ◽  
Power Delay Profile ◽  
Noise Ratio

ABSTRAKGenerasi telekomunikasi kelima (5G) diterapkan pada 2021 dengan frekuensi tinggi yang menyebabkan redaman yang besar dibandingkan pita sub-1 GHz. Penelitian ini mengkaji sistem 5G dengan frekuensi operasi 3,3 GHz dan bandwidth 99 MHz berdasarkan spesifikasi 5G dari Cyclic Prefix-Orthogonal Frequency Division Multiplexing (CP-OFDM) numerologi μ = 1 menggunakan parameter lingkungan yang diukur secara langsung di kota Bandung. Penelitian ini menemukan bahwa model kanal 5G dengan pengaruh kelembapan maksimum memiliki power delay profile (PDP) 9 path dengan nilai daya yang lebih kecil dan outage performances (𝑅>𝐶) yang lebih buruk dengan gap sebesar 0,3 dB dibandingkan dengan pengaruh kelembapan minimum. Hasil penelitian menunjukkan bahwa penggunaan convolutional codes dapat membantu menghemat Signal to Noise Ratio (SNR) dengan gap sebesar 3 dB. Hasil dari penelitian ini diharapkan dapat memberikan kontribusi bagi perkembangan komunikasi nirkabel 5G di Indonesia.Kata kunci: 5G, model kanal, convolutional codes, PDP, FER, BER. ABSTRACTThe fifth generation of telecommunications (5G) implemented in 2021, where high frequency which causes a large attenuation compared to the sub-1 GHz band. This research examines a 5G system with an operating frequency of 3.3 GHz and a bandwidth of 99 MHz based on the 5G specification of the Cyclic Prefix - Orthogonal Frequency Division Multiplexing (CP-OFDM) numerology μ = 1 using environmental parameters measured directly in Bandung, Indonesia. This research shows that the 5G channel model under maximum humidity has a 9 power delay profile (PDP) with a smaller power value and worse outage performances (𝑅>𝐶) with a gap of 0.3 dB compared to the effect of minimum humidity. The results showed that the use of convolutional codes can save the Signal to Noise Ratio (SNR) with gap of 3 dB. The results of this research are expected to contribute to the development of 5G wireless communications in Indonesia.Keywords: 5G, channel model, convolutional codes, PDP, FER, BER.

scholarly journals The effect of wavelet transform on OFDM system in modern cellular networks

2019 ◽  
Vol 15 (1) ◽  
pp. 324
Author(s):  
Mayada Faris Ghanim
Keyword(s):  
Fourier Transform ◽  
Wavelet Transform ◽  
Wireless Communications ◽  
Cellular Networks ◽  
Orthogonal Frequency Division Multiplexing ◽  
Cyclic Prefix ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Ofdm Systems ◽  
Ofdm System

Wavelet transform has many advantages that make it suitable and efficient approach to replace Fast Fourier Transform (FFT) in conventional Orthogonal Frequency Division Multiplexing (OFDM) systems. Wavelet transform is employed in modern cellular networks to remove the use of cyclic prefix, which leads to decreasing the bandwidth losses and the power of transmission. Wavelet based OFDM system is designed in order to overcome the drawbacks of OFDM system so that the proposed system is good candidate for next generation wireless communications.

scholarly journals Adaptive Beamforming Applied to OFDM Systems

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3558 ◽  
Author(s):  
Tiago Sousa ◽  
Dalton Arantes ◽  
Marcelo Fernandes
Keyword(s):  
Adaptive Algorithm ◽  
Fourier Transformation ◽  
Orthogonal Frequency Division Multiplexing ◽  
Adaptive Beamforming ◽  
Fast Fourier Transformation ◽  
Frequency Division ◽  
Ofdm Systems ◽  
Ofdm System ◽  
Guard Interval ◽  
Performance Curves

This work proposes an adaptive beamforming scheme applied to time domain, pre-FFT (Fast Fourier Transformation), Orthogonal Frequency-Division Multiplexing (OFDM) systems. This scheme improves the performance and the capacity of OFDM systems, using a supervised adaptive algorithm, with frequency domain multiplexed pilots of the OFDM system as a reference. The simplicity of the proposed structure, as well as the method used to obtain reference signals for the adaptive beamforming, are essential aspects that distinguish this paper from other publications. Details on the operation of the proposed scheme, as well as the performance curves, are presented in this manuscript. The proposal investigated here allows a significant reduction in the guard interval of the OFDM system, thereby increasing its robustness or transmission capacity.

Preliminary Investigation of Gray Coded M–Quadrature Amplitude Modulation in Orthogonal Frequency Division Multiplexing Over Additive White Gaussian Noise Channel

2012 ◽  
Author(s):  
Nor K. Noordin ◽  
Borhanuddin M. Ali ◽  
S. S. Jamuar ◽  
Tharek A. Rahman ◽  
Mahamod B. Ismail
Keyword(s):  
Bit Error Rate ◽  
Amplitude Modulation ◽  
Gaussian Noise ◽  
Orthogonal Frequency Division Multiplexing ◽  
Signal To Noise Ratio ◽  
Quadrature Amplitude Modulation ◽  
Cyclic Prefix ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Signal To Noise

Dalam makalah ini, kami menyelidik prestasi M–Modulasi Amplitud Kuadratur terkod–Gray dalam sistem penghantaran menggunakan skema Multiplexan Pembahagian Frekuensi Ortogonal (OFDM) melalui saluran hingar Gaussian (AWGN). QAM terkod Gray dengan 1 bit ke 8 bit per simbol bersamaan dengan 2–QAM ke 256–QAM dijana dan dimasukkan ke dalam sistem penghantaran OFDM. Prestasi sistem dalam bentuk kadar ralat bit (BER) diberi berbanding saiz jelmaan Fourier pantas (FFT), bilangan sub-pembawa, panjang prefix-kitaran, dan toleransi terhadap nisbah isyarat kepada hingar (SNR) dalam saluran. Dapatan awal menunjukkan hanya modulasi 16–QAM ke bawah boleh diterimapakai untuk mencapai BER sebanyak 10–3 dengan SNR sekurang-kurangnya 20 dB. Peringkat modulasi yang lebih tinggi seperti 256–QAM memerlukan SNR sebanyak 50 dB untuk mencapai hasil BER yang sama. Kajian juga menunjukkan prestasi sistem ini tidak tergugat dengan perubahan saiz FFT mahupun panjang prefix-kitaran yang dimasukkan ke dalam isyarat yang dihantar. Walau bagaimanapun, bilangan sub-pembawa bergantung kepada peringkat QAM yang digunakan untuk suatu nilai SNR yang diberi. Kata kunci: Multiplexan pembahagian frekuensi ortogonal (OFDM), modulasi kuadratur (QAM), pengkodan gray, dan jelmaan fourier pantas In this paper, we investigate the performance of Gray encoding M–Quadrature Amplitude Modulation (QAM) schemes in Orthogonal Frequency Division Multiplexing (OFDM) transmission over added white Gaussian noise (AWGN) channel. Gray–coded QAM with 1 to 8–bit symbol corresponding to 2 to 256–QAM respectively is generated and fed into OFDM transmission system. Performance in terms of bit error rate (BER) is presented against OFDM fast Fourier transform (FFT) size, subcarrier number, length of cyclic prefix, and tolerance to signal to noise ratio of the channel. Preliminary results show that only 16 and lower level–QAM are attractive to achieve a bit error rate (BER) of 10–3 with signal to noise ratio of at least 20 dB. The higher level QAM such as 256–QAM scheme will require at least a SNR of 50 db to achieve similar outcome. The study also shows that the performance of the system is not affected by the number of fft–points used, or the length of cyclic prefix inserted to the transmitted signal. However, the number of subcarriers does depend on the level of QAM used at a given SNR value. Keywords: Orthogonal frequency division multiplexing (OFDM), quadrature amplitude modulation (QAM), gray coding, fast fourier transform (FFT)

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