Journal articles: 'Coded orthogonal frequencydivision multiplexing'

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Nejwa, El Maammar, Bri Seddik, Foshi Jaouad, Amine Ihedrane Mohammed, and Fadl Adiba El. "High performance binary LDPC-coded OFDM systems over indoor PLC channels." TELKOMNIKA (Telecommunication, Computing, Electronics and Control) 19, no. 4 (2021): 1388–95. https://doi.org/10.12928/telkomnika.v19i4.20401.

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Power line communication (PLC) technology is actually among the most renowned technologies for home environments due to their low-cost installation opportunities. In this study, the bit error rate (BER) performances of binary low-density parity check (LDPC) coded orthogonal frequencydivision multiplexing (OFDM) systems have been considered over indoor PLC channels. Performances comparison of diverse soft and hard decision LDPC decoder schemes such as Min-Sum (MS), weighted bit flipping (WBF), gradient descent bit-flip (GDBF), noisy gradient descent bit-flip (NGDBF) and its few variants including the single-bit NGDBF (S-NGDBF), multi-bit NGDBF (M-NGDBF) and smoothed-multi-bit NGDBF (SM-NGDBF) decoders were examined in the modeled network. To evaluate the BER performance analyses three different PLC channel scenarios were generated by using new and more realistic PLC channel model proposal were also employed. All of the simulations performed in Canete’s PLC channel model showed that remarkable performance improvement can be achieved by using short-length LDPC codes. Especially, the improvements are striking when the MS or SM-NGDBF decoding algorithms are employed on the receiver side.

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Tashatov, Nurlan N., Manara A. Seksembayeva, Gennady V. Ovechkin, Dina Satybaldina, and Yerzhan N. Seitkulov. "Interference immunity and energy efficiency of digital communications systems in multipath channel with fading." Indonesian Journal of Electrical Engineering and Computer Science 27, no. 3 (2022): 1412–18. https://doi.org/10.11591/ijeecs.v27.i3.pp1412-1418.

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In the study of measures to improve channel efficiency, we developed and presented a performance analysis of a digital communication system for image transmission in a multipath channel with fading, in the MATLAB/Simulink environment, one of the main advantages being that it provides high interference immunity in the presence of noise and interference and signal delays. The scheme has been investigated for bit error rate (BER) on additive white Gaussian noise (AWGN) channel and multipath Rice and Rayleigh fading channel operating under the influence of inter-symbol interference (hereinafter ISI) and different parameters for the channel, where we considered cases of signal delay similar for EPA (extended pedestrian a model (EPA) standards). In this paper, we estimate the effectiveness of compensation for signal distortion in radio channels with fading on the basis coded orthogonal frequency-division multiplexing (COFDM) technology, an adaptive equalizer, amplifiers on the transmitter side and a normalizer on the receiver side, which is an acute problem in the field of wireless communication. This system can be applied to transmit better quality high-resolution radiological images over a wireless network inside a building and for a model analogous of pedestrian traffic.

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Gokceli, Selahattin, and Gunes Karabulut Kurt. "Superposition Coded-Orthogonal Frequency Division Multiplexing." IEEE Access 6 (2018): 14842–56. http://dx.doi.org/10.1109/access.2018.2814050.

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Farhan, Mhnd. "Performance Analysis of Coded Frequency Division Multiplexing." European Journal of Engineering and Formal Sciences 2, no. 3 (2018): 56. http://dx.doi.org/10.26417/ejef.v2i3.p56-60.

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This paper studies the performance of coded orthogonal frequency division multiplexing system using two modulation techniques, quadrature phase shift keying(QPSK) and quadrature amplitude modulation(QAM). The convolutional code is used as error-correcting-code. The communication channel used is vehicular channel. Simulation results show that the performance of coded orthogonal frequency division multiplexing system with QPSK is better than that with QAM

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Song, Haiyang, Jianan Li, Dakui Lin, et al. "Reducing the Crosstalk in Collinear Holographic Data Storage Systems Based on Random Position Orthogonal Phase-Coding Reference." Photonics 10, no. 10 (2023): 1160. http://dx.doi.org/10.3390/photonics10101160.

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Previous studies have shown that orthogonal phase-coding multiplexing performs well with low crosstalk in conventional off-axis systems. However, noticeable crosstalk occurs when applying the orthogonal phase-coding multiplexing to collinear holographic data storage systems. This paper demonstrates the crosstalk generation mechanism, features, and elimination methods. The crosstalk is caused by an inconsistency in the intensity reconstruction from the orthogonal phase-coded reference wave. The intensity fluctuation range was approximately 40%. Moreover, the more concentrated the distribution of pixels with the same phase key, the more pronounced the crosstalk. We propose an effective random orthogonal phase-coding reference wave method to reduce the crosstalk. The orthogonal phase-coded reference wave is randomly distributed over the entire reference wave. These disordered orthogonal phase-coded reference waves achieve consistent reconstruction intensities exhibiting the desired low-crosstalk storage effect. The average correlation coefficient between pages decreased by 73%, and the similarity decreased by 85%. This orthogonal phase-coding multiplexing method can be applied to encrypted holographic data storage. The low-crosstalk nature of this technique will make the encryption system more secure.

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Farhan, Mhnd. "Performance Analysis of Coded Frequency Division Multiplexing." European Journal of Engineering and Formal Sciences 2, no. 3 (2018): 56–60. http://dx.doi.org/10.2478/ejef-2018-0017.

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Abstract This paper studies the performance of coded orthogonal frequency division multiplexing system using two modulation techniques, quadrature phase shift keying(QPSK) and quadrature amplitude modulation(QAM). The convolutional code is used as error-correcting-code. The communication channel used is vehicular channel. Simulation results show that the performance of coded orthogonal frequency division multiplexing system with QPSK is better than that with QAM

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Lakshmi, Dr M. Vijaya. "Deep Learning Aided 5G Channel Estimation." International Journal for Research in Applied Science and Engineering Technology 11, no. 6 (2023): 3821–26. http://dx.doi.org/10.22214/ijraset.2023.54202.

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Abstract: Wireless communications involves the transfer of voiceand data without a cable or wires. It uses orthogonal frequencydivision multiplexing, also known as a multicarrier transmission technique. In multiple input multiple output (MIMO) wireless communication (4G and 5G technologies), channel estimation is crucial. Multiple antennas are used at both the transmit and receive sides ofa MIMO system to increase spectral efficiency and reliability. In 5G channel estimation is performed to improve the accuracy of the received signal. Least-squares estimation is a cheap method with relatively large channel estimationerrors, but it is supported in this work by using a new channel estimation method that leverages deep learning. LS (least squares) and MMSE (minimum mean squared error) are two popular traditional approaches to channel estimation, but deep learning provides much more accurate results than previous channel estimation methods.

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Farhan, Mhnd. "Coded Orthogonal Frequency Division Multiplexing System : An Overview." Indonesian Applied Physics Letters 4, no. 2 (2023): 57–64. http://dx.doi.org/10.20473/iapl.v4i2.49248.

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This article compares the performance of two modulation techniques—quadrature phase shift keying (QPSK) and M-ary quadrature amplitude modulation (M-QAM) with M=8, 16, 32, and 64—in a coded orthogonal frequency division multiplexing system. As an error-correcting code, convolutional technology is employed. A vehicular channel with additive white gaussian noise (AWGN) is utilized for communication. According to simulation data, for QPSK and M-QAM, a coded orthogonal frequency division multiplexing system performs better than an uncoded one. Additionally, the system performs better with QPSK than it does with M-QAM. Additionally, when M rises, the performance declines.

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Francis, Xavier, Babu S. Hari, A. Rajesh, and Basha SK Jameer. "Low Code Coding Approach for ofdm Systems Coded with the Progressive Transmission." International Journal of Innovative Technology and Exploring Engineering (IJITEE) 9, no. 12 (2020): 185–88. https://doi.org/10.35940/ijitee.L7962.1091220.

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Orthogonal Frequency Division Multiplexing (OFDM) offers several benefits such as flexible wrapping, mail sign interference, reduced complexity and more. The only way to match parallel channels is to have genetic diversity in multipath channels. Various coded of OFDM systems reported using some form of channel coding or pre-coding to improve system performance. The execution of irrational orthogonal frequency division multiplexing (OFDM) on blurred channels is usually better than introducing some coding. Various coding schemes for off-OFDM have been reported in the literature.

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Kahlert, Moritz, Tai Fei, Yuming Wang, Claas Tebruegge, and Markus Gardill. "Unified Model and Survey on Modulation Schemes for Next-Generation Automotive Radar Systems." Remote Sensing 17, no. 8 (2025): 1355. https://doi.org/10.3390/rs17081355.

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Commercial automotive radar systems for advanced driver assistance systems (ADASs) have relied on frequency-modulated continuous wave (FMCW) waveforms for years due to their low-cost hardware, simple signal processing, and established academic and industrial expertise. However, FMCW systems face several challenges, including limited unambiguous velocity, restricted multiplexing of transmit signals, and susceptibility to interference. This work introduces a unified automotive radar signal model and reviews the alternative modulation schemes such as phase-coded frequency-modulated continuous wave (PC-FMCW), phase-modulated continuous wave (PMCW), orthogonal frequency-division multiplexing (OFDM), orthogonal chirp division multiplexing (OCDM), and orthogonal time frequency space (OTFS). These schemes are assessed against key technological and economic criteria and compared with FMCW, highlighting their respective strengths and limitations.

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Djordjevic, I. B. "Coded-orthogonal frequency division multiplexing in hybrid optical networks." IET Optoelectronics 4, no. 1 (2010): 17. http://dx.doi.org/10.1049/iet-opt.2008.0059.

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Koti, Jayasudha, and Braj Kishore Mishra. "BER Performance Comparison of DCO-OFDM and Convolutional Coded DCO-OFDM in IM/DD Systems." International Journal of Electronics, Communications, and Measurement Engineering 8, no. 2 (2019): 26–39. http://dx.doi.org/10.4018/ijecme.2019070102.

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Optical wireless communication (OWC) is an alternative technology to meet the demands of the exponentially-growing high data rate applications run by broadband users. The implementation of single carrier modulation techniques in OWC is an age old technology, but for the last few years research is focused towards the multicarrier modulation techniques in OWC. In OWC, information is carried using intensity modulation and retrieved using direct detection. To perform intensity modulation, the baseband signal should be a unipolar signal. To obtain a unipolar signal, various techniques such as DC-biased orthogonal frequency division multiplexing (DCO-OFDM), Asymmetrically clipped orthogonal frequency division multiplexing (ACO-OFDM), Flip orthogonal frequency division multiplexing (Flip-OFDM) and Unipolar orthogonal frequency division multiplexing (U-OFDM) techniques are reported in the literature. Though the DCO-OFDM is spectrally efficient compared to other techniques it requires more power to achieve the targeted BER. In this article, a convolutional Coded DCO-OFDM (CDCO-OFDM) has been introduced by applying channel coding. A convolutional encoder and a hard-decision Viterbi decoder are considered in CDCO-OFDM. It has been observed that CDCO-OFDM requires less transmitted power than DCO-OFDM to attain the targeted BER. The performance of DCO-OFDM and CDCO-OFDM is evaluated for 4, 16, 64 QAM- 7dB and 13dB bias, in the presence of the additive white Gaussian noise (AWGN) channel. It is observed that CDCO requires less power to transmit than DCO-OFDM for the BER 10-4.

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Nishida, Satoshi, Ryo Higuchi, Hiroshi Mochizuki, and Hideo Nakamura. "Error-Correction Coded Orthogonal Frequency Division Multiplexing Track-Circuit Transmission." IEEJ Transactions on Industry Applications 141, no. 3 (2021): 258–68. http://dx.doi.org/10.1541/ieejias.141.258.

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Han, Jing, Wentao Shi, and Geert Leus. "Space-frequency coded orthogonal signal-division multiplexing over underwater acoustic channels." Journal of the Acoustical Society of America 141, no. 6 (2017): EL513—EL518. http://dx.doi.org/10.1121/1.4983632.

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Fadil, Tariq. "SECURE VIDEO CODED SYSTEM MODEL." Iraqi Journal for Computers and Informatics 42, no. 1 (2016): 5–9. http://dx.doi.org/10.25195/ijci.v42i1.78.

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In this paper, overall system model, shown in Figure (1), of video compression-encryption-transmitter/decompression-dencryption-receiver was designed and implemented. The modified video codec system has used and in addition to compression/decompression, theencryption/decryption video signal by using chaotic neural network (CNN) algorithm was done. Both of quantized vector data and motion vector data have been encrypted by CNN. The compressed and encrypted video data stream has been sent to receiver by using orthogonal frequency division multiplexing (OFDM) modulation technique. The system model was designed according to video signal sample size of 176 × 144 (QCIFstandard format) with rate of 30 frames per second. Overall system model integrates and operates successfully with acceptable performance results.

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Zheng, H. "Applying Coded Orthogonal Frequency-Division Multiplexing to V-Band Millimeter Wave System." International Journal of Infrared and Millimeter Waves 25, no. 7 (2004): 1075–86. http://dx.doi.org/10.1023/b:ijim.0000037656.65508.d0.

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Kryukov, Yakov V., Dmitriy A. Pokamestov, and Serafim A. Novichkov. "Symbol Error-Rate Analytical Expressions for a Two-User PD-NOMA System with Square QAM." Symmetry 13, no. 11 (2021): 2153. http://dx.doi.org/10.3390/sym13112153.

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Power domain non-orthogonal multiple access (PD-NOMA) is one of the most perspective multiplexing technologies that allows improving the capacity of actual networks. Unlike orthogonal multiple access (OMA), the PD-NOMA non-orthogonally schedules multiple users in the power domain in the same orthogonal time-spectrum resource segment. Thus, a non-orthogonal multiplexed signal is a combination of several user signals (usually, modulation and coding schemes (MCS) based on quadrature amplitude modulation) with different power weights. The symbol error rate (SER) and bit error rate (BER) performances are one of the main quality characteristics of any commutation channel. The issue is that a known analytical expression for BER and SER calculation for conventional OMA cannot be applied in terms of the PD-NOMA. In the following work, we have derived the SER and BER analytical expressions for gray-coded square quadrature amplitude modulation (QAM) user channels that are transmitted in two-user PD-NOMA channel under additive white Gaussian noise (AWGN). Through the simulation, the verification of the provided expressions is presented for four multiplexing configurations with various user power weights and QAM order combinations.

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Kim, Tae, and Dong Kim. "Multi-Dimensional Sparse-Coded Ambient Backscatter Communication for Massive IoT Networks." Energies 11, no. 10 (2018): 2855. http://dx.doi.org/10.3390/en11102855.

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In this paper, we propose a multi-dimensional sparse-coded ambient backscatter communication (MSC-AmBC) system for long-range and high-rate massive Internet of things (IoT) networks. We utilize the characteristics of the ambient sources employing orthogonal frequency division multiplexing (OFDM) modulation to mitigate strong direct-link interference and improve signal detection of AmBC at the reader. Also, utilization of the sparsity originated from the duty-cycling operation of batteryless RF tags is proposed to increase the dimension of signal space of backscatter signals to achieve either diversity or multiplexing gains in AmBC. We propose optimal constellation mapping and reflection coefficient projection and expansion methods to effectively construct multi-dimensional constellation for high-order backscatter modulation while guaranteeing sufficient energy harvesting opportunities at these tags. Simulation results confirm the feasibility of the long-range and high-rate AmBC in massive IoT networks where a huge number of active ambient sources and passive RF tags coexist.

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Abbas, S. M. "DESIGN OF SPACE TIME TRELLIS CODED OFDM." Journal of Engineering 14, no. 03 (2024): 2684–98. http://dx.doi.org/10.31026/j.eng.2008.03.12.

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Space Time Trellis Code (STTC) is a technique that can be used to improve the performance ofthe Orthogonal Frequency Division Multiplexing (OFDM) system over wireless channels byproviding both coding gain and diversity gain. STTC is combined from two codes, Trellis CodeModulation (TCM) as an inner code and Space Time Block Code (STBC) as an outer code. TCMwhich combines the choice of a modulation scheme with that of a convolutional code provides thecoding gain, and the other code provides the diversity gain. Simulation is done over flat fading andfrequency selective Rayleigh fading channel for Eight Phase Shift Keying (8-PSK) TCM. It foundthat the best results are obtained for the case of two transmitters and three receivers which have again of about 18dB over that without STBC.

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Oluwafemi, IlesanmiB, and StanleyH Mneney. "Review of Space-time Coded Orthogonal Frequency Division Multiplexing Systems for Wireless Communication." IETE Technical Review 30, no. 5 (2013): 417. http://dx.doi.org/10.4103/0256-4602.123126.

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Li, Boyu, and Ender Ayanoglu. "Diversity Analysis of Bit-Interleaved Coded Multiple Beamforming with Orthogonal Frequency Division Multiplexing." IEEE Transactions on Communications 61, no. 9 (2013): 3794–805. http://dx.doi.org/10.1109/tcomm.2013.080113.130247.

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Guo, Jianzhong, Jinpeng Xiao, Jing Chen, et al. "Performance Analysis of LDPC-Coded OFDM in Underwater Wireless Optical Communications." Photonics 10, no. 3 (2023): 330. http://dx.doi.org/10.3390/photonics10030330.

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The performance of Low-Density Parity-Check (LDPC)-coded Orthogonal Frequency Division Multiplexing (OFDM) is investigated over turbulence channels in underwater wireless optical communications (UWOC). The relation between the bit error ratio (BER) and parameters such as the scintillation coefficient, signal-to-noise ratio (SNR), length of LDPC code, and order of OFDM is quantified by simulation. Results show that while the OFDM with subcarrier quadrature amplitude modulation (QAM-OFDM) has slightly better anti-turbulence performance than the OFDM with subcarrier phase shift keying modulation (PSK-OFDM), the LDPC-coded QAM-OFDM has a much better performance than the QAM-OFDM and the LDPC-coded PSK-OFDM, and, at SNR = 12, it decreases the BER by four orders of magnitude compared to the 16QAM-OFDM system when the scintillation coefficient σξ2 = 0.05.

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Wirastuti, N. M. A. E. D., I. M. A. Suyadnya, and D. C. Khrisne. "Performance Assessment of OFDM System using Reed-Solomon Codes over Fading Channels." Journal of Electrical, Electronics and Informatics 2, no. 2 (2018): 48. http://dx.doi.org/10.24843/jeei.2018.v02.i02.p06.

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This paper study the performance of Orthogonal Frequency Division Multiplexing (OFDM) system over AWGN and Rayleigh fading channels. OFDM performs multi-carrier transmission where all the subcarriers are orthogonal to each other. The channel coding was applied to improve the OFDM system performance. Reed Solomon (RS) codes was chosen that an efficient channel coding algorithm and has intense error correction ability. Adding the benefits of multicarrier OFDM system and Reed Solomon codes to achieve the expected system performance. The coded OFDM system was modeled over and simulated using Matlab. The bit error rate (BER) and energy bit (Eb) per noise power density (No) was performed during system simulations. QPSK modulation was used to modulate the random bits. From the simulation results It can be seen that BER vs. EB/No parameter for Coded OFDM system lower than uncoded OFDM. This was because RS codes succeed to correcting the error generated along data transmission.

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Wang, Leijun, Wenbo Zhou, Zian Tong, et al. "Transformer-Based Detection for Highly Mobile Coded OFDM Systems." Entropy 25, no. 6 (2023): 852. http://dx.doi.org/10.3390/e25060852.

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This paper is concerned with mobile coded orthogonal frequency division multiplexing (OFDM) systems. In the high-speed railway wireless communication system, an equalizer or detector should be used to mitigate the intercarrier interference (ICI) and deliver the soft message to the decoder with the soft demapper. In this paper, a Transformer-based detector/demapper is proposed to improve the error performance of the mobile coded OFDM system. The soft modulated symbol probabilities are computed by the Transformer network, and are then used to calculate the mutual information to allocate the code rate. Then, the network computes the codeword soft bit probabilities, which are delivered to the classical belief propagation (BP) decoder. For comparison, a deep neural network (DNN)-based system is also presented. Numerical results show that the Transformer-based coded OFDM system outperforms both the DNN-based and the conventional system.

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Yadav, R. Meghana. "TURBO Coded OFDM Improves BER Performance Evaluation for Digital Video Broadcasting." International Journal for Research in Applied Science and Engineering Technology 9, no. 9 (2021): 1950–54. http://dx.doi.org/10.22214/ijraset.2021.38220.

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Abstract: Turbo coded Orthogonal Frequency Division Multiplexing (OFDM) is attractive technique for high data rate in wireless communication applications, mobile communications (4G) and Wireless Metropolitan Area Networks (WMAN) and Digital Video Broadcasting (DVB). The performance of TURBO Coded 16 QAM and 64 QAM schemes with OFDM for high speed data rate applications is compared which is used in digital video broadcasting. BER analysis is used to assess the system's performance. Due to the high data rate of 64 QAM, attaining BER of ૚૙ି૝ requires Eb/No of 0.9 dB in 16QAM, whereas obtaining BER of ૚૙ି૝ requires 0.17 dB in 64QAM. By using OFDM removes Inter Symbol Interference (ISI) and Adjacent Channel Interference (ACI). Keywords: Wireless communication, mobile communication, OFDM, QAM, TURBO Encoding

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Zhang, Weite, Yi Huang, Juan Heredia-Juesas, and Jose A. Martinez-Lorenzo. "Software-Defined Millimeter-Wave Multistatic Radar With Space-Time-Coded Orthogonal Frequency-Division Multiplexing." IEEE Transactions on Microwave Theory and Techniques 70, no. 3 (2022): 1620–29. http://dx.doi.org/10.1109/tmtt.2021.3134182.

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Zhang, Yu, Ke Yang, Jingyu Hua, Hong Peng, and Weidang Lu. "Rateless coded Orthogonal Frequency Division Multiplexing system design based on intercarrier interference self-cancelation." International Journal of Communication Systems 33, no. 11 (2020): e4396. http://dx.doi.org/10.1002/dac.4396.

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Jagadeesan, D., K. Palani, and G. Asha. "Multiple-Input-Single-Output Based a Novel Pilot-Aided Channel Estimation for Cyclic Delay Diversity Orthogonal Frequency Division Multiplexing Frameworks." Journal of Computational and Theoretical Nanoscience 16, no. 2 (2019): 697–701. http://dx.doi.org/10.1166/jctn.2019.7793.

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A low-complexity standard transmit diversity scheme for coded orthogonal frequency division multiplexing (OFDM) frameworks is cyclic delay diversity (CDD). As the cyclic delay esteem expands the diversity effect also increases. However, the channel estimation turns out to be more troublesome because of increased frequency selectivity as the increased cyclic delay value. In this paper we discussed about dissimilar channel estimation schemes and to conclude we proposed a novel pilot-aided channel estimation scheme for CDD to estimate the channel in an enhanced way. Our scheme estimates each channel separately and achieves significant performance improvement.

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Maammar, Nejwa El, Seddik Bri, and Jaouad Foshi. "Performances Concatenated LDPC based STBC-OFDM System and MRC Receivers." International Journal of Electrical and Computer Engineering (IJECE) 8, no. 1 (2018): 622. http://dx.doi.org/10.11591/ijece.v8i1.pp622-630.

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This paper presents the bit error rate performance of the low density parity check (LDPC) with the concatenation of convolutional channel coding based orthogonal frequency-division-multiplexing (OFDM) using space time block coded (STBC). The OFDM wireless communication system incorporates 3/4-rated convolutional encoder under various digital modulations (BPSK, QPSK and QAM) over an additative white gaussian noise (AWGN) and fading (Raleigh and Rician) channels. At the receiving section of the simulated system, Maximum Ratio combining (MRC) channel equalization technique has been implemented to extract transmitted symbols without enhancing noise power.

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López Parrado, Alexander, Jaime Velasco Medina, and Julián Adolfo Ramírez Gutiérrez. "Efficient hardware implementation of a full COFDM processor with robust channel equalization and reduced power consumption." Revista Facultad de Ingeniería Universidad de Antioquia, no. 68 (October 18, 2013): 48–60. http://dx.doi.org/10.17533/udea.redin.17040.

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This work presents the design of a 12 Mb/s Coded Orthogonal Frequency Division Multiplexing (COFDM) baseband processor for the standard IEEE 802.11a. The COFDM baseband processor was designed by using ourdesigned circuits for carrier phase correction, symbol timing synchronization, robust channel equalization and Viterbi decoding. These circuits are flexible, parameterized and described by using generic structural VHDL. The COFDM processor has two clock domains for reducing power consumption, it was synthesized on a Stratix II FPGA, and it was experimentally tested by using 2.4 GHz Radio Frequency (RF) circuitry.

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Nejwa, El Maammar, Bri Seddik, and Foshi Jaouad. "Performances Concatenated LDPC based STBC-OFDM System and MRC Receivers." International Journal of Electrical and Computer Engineering (IJECE) 8, no. 1 (2018): 622–30. https://doi.org/10.11591/ijece.v8i1.pp622-630.

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This paper presents the bit error rate performance of the low density parity check (LDPC) with the concatenation of convolutional channel coding based orthogonal frequency-division-multiplexing (OFDM) using space time block coded (STBC). The OFDM wireless communication system incorporates 3/4-rated convolutional encoder under various digital modulations (BPSK, QPSK and QAM) over an additative white gaussian noise (AWGN) and fading (Raleigh and Rician) channels. At the receiving section of the simulated system, Maximum Ratio combining (MRC) channel equalization technique has been implemented to extract transmitted symbols without enhancing noise power.

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Li, Jiazhe, Siyi Li, Heng Dong, and Zhuoming Li. "Intrinsic Interference Cancellation Scheme for FBMC-OQAM Systems Based on Power Multiplexing." Electronics 11, no. 9 (2022): 1443. http://dx.doi.org/10.3390/electronics11091443.

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As a competitive candidate of orthogonal frequency-division multiplexing (OFDM), filter-bank multicarrier (FBMC) has significant advantages in low spectrum leakage, relaxed synchronization requirements and high spectral efficiency. However, the loss of orthogonality leads to intrinsic interference in FBMC, whereas most methods eliminate it by sacrificing data symbols, resulting in a non-negligible decrease in spectral efficiency. In this context, we propose a new method that eliminates intrinsic interference completely without sacrificing any data symbols thanks to the power multiplexing in the transmitter and the successive interference cancellation scheme in the receiver, contributing to a higher spectral efficiency compared with previous methods. Both the analytical and simulation results demonstrate that the proposed method has higher spectral efficiency and similar power efficiency compared with the traditional coded auxiliary pilot (CAP) method without a notable decrease in bit error rate (BER) performance.

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Ye, Ming Kun, Qin Zhu, Peng Cheng Dai, and Jun Tang. "Design of QAM-OFDM Radar-Communication Integrated Signal Based on Golay Complementary sequences." Journal of Physics: Conference Series 2085, no. 1 (2021): 012010. http://dx.doi.org/10.1088/1742-6596/2085/1/012010.

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Abstract The integration of radar and communication is conducive to improving the utilization rate of hardware resources and spectrum. To address the issue that the communication information in orthogonal frequency division multiplexing (OFDM) integrated signal for radar and communication affects detection performance, an OFDM integrated signal for radar and communication based on precoding was proposed. The communication information of the integrated signal was pre-coded by using the Gray Complementary Sequences (GCS) with better correlation performance to improve the performance of the ambiguity function of the integrated signal and its detection ability. Simulation results show that GCS have better correlation performance compared to M and Gold sequences, and the OFDM integrated signal pre-coded by GCS has lower Peak Sidelobes Ratio (PSLR) and comparable radar performance to LFM.

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Aly, Rana M., Amira Zaki, Waleed K. Badawi, and Moustafa H. Aly. "Time Coding OTDM MIMO System Based on Singular Value Decomposition for 5G Applications." Applied Sciences 9, no. 13 (2019): 2691. http://dx.doi.org/10.3390/app9132691.

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For 5G and beyond cellular communication systems, new coding and modulation techniques are suggested to reach the requirements of high data rate and quality of service. In this paper, a new space-time coded orthogonal transform division multiplexing (STC OTDM) technique is proposed for 5G applications. The proposed system is used to enhance the data rate and performance of the orthogonal transform division multiplexing (OTDM) technique. The proposed system is based on using space-time coding (STC) with OTDM to increase the system diversity and consequently the system performance. The OTDM technique is based on transmitting data on orthogonal basis functions obtained from the Singular Value Decomposition (SVD) of the channel impulse response of the desired user. Various modulation techniques like QPSK, 64-QAM, and 256-QAM are investigated using different subcarriers and channel models. The simulation results show that the proposed system achieved a better performance when compared to classical and recent multicarrier techniques. The proposed technique increases the diversity gain resulting in a decrease in the fading effect of the multipath channel and an enhancement in the bit error rate (BER) performance. The proposed technique also provides a secure data transmission to the desired user as his data is sent on the basis functions extracted from his own channel impulse response that cannot be decoded by other users.

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Kim, Bong-seok, Dongjun Na, and Kwonhue Choi. "Partial ML Detection for Frequency-Asynchronous Distributed Alamouti-Coded (FADAC) OFDM." Wireless Communications and Mobile Computing 2019 (September 30, 2019): 1–10. http://dx.doi.org/10.1155/2019/4319802.

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To further enhance frequency-asynchronous distributed Alamouti-coded (FADAC) orthogonal frequency division multiplexing (OFDM), we propose a new scheme which combines the partial maximum likelihood detection (PMLD) to the residual intercarrier interference cancellation (RIC). In order to decrease the performance gap from intercarrier interference- (ICI-) free level after single time iteration of the RIC, the final stage of the proposed scheme performs the PMLD limited to the symbols of less-reliable decision variables. We show that with the practically acceptable candidate symbol set size, a single iteration for RIC is enough to achieve the ICI-free performance. Moreover, the proposed scheme substantially expands the allowable ranges of the three undesirable terms, i.e., the timing and frequency offsets between the transmit antennas and the multipath delay spreads.

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Sangirov, Gulomjon, Yong Qing Fu, and Ye Fang. "A MMSE Channel Estimation Method in QC-LDPC Coded OFDM Systems." Advanced Materials Research 989-994 (July 2014): 3759–62. http://dx.doi.org/10.4028/www.scientific.net/amr.989-994.3759.

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An orthogonal frequency division multiplexing (OFDM) is one of the effective techniques used in wireless communications. In OFDM systems, channel impairments due to multipath dispersive wireless channels can cause deep fades in wireless channels. The OFDM receiver also requires an accurate and computationally efficient channel state information when coherent detection is involved. Therefore, it needs a good robust estimation method of the channel in wireless communication for OFDM systems. And one of these channel estimation methods is minimum mean square error (MMSE) channel estimation. MMSE channel estimation one most used method in OFDM systems. In this work we enhanced robustness of MMSE channel estimation by using it in base of quasi-cyclic low density parity check (QC-LDPC) coded OFDM system.

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Murad, Mohsin, Imran A. Tasadduq, and Pablo Otero. "Coded-GFDM for Reliable Communication in Underwater Acoustic Channels." Sensors 22, no. 7 (2022): 2639. http://dx.doi.org/10.3390/s22072639.

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The performance of the coded generalized frequency division multiplexing (GFDM) transceiver has been evaluated in a shallow underwater acoustic channel (UAC). Acoustic transmission is the scheme of choice for communication in UAC since radio waves suffer from absorption and light waves scatter. Although orthogonal frequency division multiplexing (OFDM) has found its ground for multicarrier acoustic underwater communication, it suffers from high peak to average power ratio (PAPR) and out of band (OOB) emissions. We propose a coded-GFDM based multicarrier system since GFDM has a higher spectral efficiency compared to a traditional OFDM system. In doing so, we assess two block codes, namely Bose, Chaudari, and Hocquenghem (BCH) codes, Reed-Solomon (RS) codes, and several convolutional codes. We present the error performances of these codes when used with GFDM. Furthermore, we evaluate the performance of the proposed system using two equalizers: Matched Filter (MF) and Zero-Forcing (ZF). Simulation results show that among the various block coding schemes that we tested, BCH (31,6) and RS (15,3) give the best error performance. Among the convolutional codes that we tested, rate 1/4 convolutional codes give the best performance. However, the performance of BCH and RS codes is much better than the convolutional codes. Moreover, the performance of the ZF equalizer is marginally better than the MF equalizer. In conclusion, using the channel coding schemes with GFDM improves error performance manifolds thereby increasing the reliability of the GFDM system despite slightly higher complexity.

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Shentu, Jinwen, and Jean Armstrong. "Blind frequency offset estimation for overlap PCC-OFDM systems in presence of phase noise." Journal of Telecommunications and Information Technology, no. 2 (June 30, 2003): 17–27. http://dx.doi.org/10.26636/jtit.2003.2.174.

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This paper presents a technique for frequency offset estimation for polynomial cancellation coded orthogonal frequency division multiplexing with symbols overlapped in the time domain (overlap PCC-OFDM) in the presence of phase noise. The frequency offset estimator is designed based on the subcarrier pair imbalance (SPI) caused by frequency offset. The estimation is performed in the frequency domain at the output of the receiver discrete Fourier transform (DFT). No training symbols or pilot tones are required. Simulations show that this estimator is an approximately linear function of frequency offset. Phase noise does not significantly affect the variance performance of the estimator.

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Yang, Qinbiao, Zulin Wang, and Qin Huang. "A CCM-Based OFDM System with Low PAPR for Sparse Source." Wireless Communications and Mobile Computing 2018 (2018): 1–7. http://dx.doi.org/10.1155/2018/8923478.

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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.

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Godwin, R. S. Jim, K. Veena, and D. Sriram Kumar. "Performance analysis of colour coded multiple access orthogonal frequency division multiplexing visible light communication system." International Journal of Image Mining 2, no. 3/4 (2017): 301. http://dx.doi.org/10.1504/ijim.2017.085317.

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Jim Godwin, R. S., K. Veena, and D. Sriram Kumar. "Performance analysis of colour coded multiple access orthogonal frequency division multiplexing visible light communication system." International Journal of Image Mining 2, no. 3/4 (2017): 301. http://dx.doi.org/10.1504/ijim.2017.10006317.

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Boyu Li and E. Ayanoglu. "Full-Diversity Precoding Design of Bit-Interleaved Coded Multiple Beamforming with Orthogonal Frequency Division Multiplexing." IEEE Transactions on Communications 61, no. 6 (2013): 2432–45. http://dx.doi.org/10.1109/tcomm.2013.041113.120688.

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Chen, Yuchuan. "Research on the Technology and Application of Remote Wireless Transmission of Digital Image Signal." Applied and Computational Engineering 100, no. 1 (2024): 61–66. http://dx.doi.org/10.54254/2755-2721/100/20251725.

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Abstract. With the increasing demand for remote real-time high-quality video transmission, especially in the context of large area applications of unmanned aerial vehicle (UAV) and remote location instant live broadcast, traditional wired transmission methods have been surpassed by digital transmission methods due to their superior performance in image quality, transmission distance and delay. Therefore, this study focuses on the application of digital image wireless transmission in remote scenarios such as UAVs, including key digital transmission technologies such as Orthogonal Frequency Division Multiplexing (OFDM) and Coded Orthogonal Frequency Division Multiplexing (COFDM), as well as public network link communication technologies such as 4G and 5G, by means of a literature study and a case study. It also analyzes the development of WiFi, Lightbridge and OcuSync graphics transmission systems using DJI brand products as case studies. The analysis shows that digital image wireless transmission, especially COFDM and advanced proprietary systems such as DJI's OcuSync, has significant advantages in terms of transmission distance, interference immunity, encryption techniques, and reusability. However, factors such as building obstruction, frequency interference, and weather conditions can affect the transmission quality. To mitigate these challenges, solutions are proposed, such as auxiliary signal enhancement systems, adaptive frequency hopping and software-defined radio technologies.

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K. Abed, Ahmed. "A New Technique for PAPR Reduction in OFDM System." University of Thi-Qar Journal for Engineering Sciences 2, no. 2 (2011): 41–51. http://dx.doi.org/10.31663/utjes.v2i2.193.

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Orthogonal frequency division multiplexing (OFDM) is an attractive technique for modern wireless communication. One major drawback of orthogonal frequency division multiplexing schemes is the high peak to average power ratio (PAPR) of the output signal. Selecting mapping (SLM) and partial transmit sequences (PTS) are two important techniques for reducing PAPR, but they need to transmit side information to indicate how the transmitter generates the signals. In this paper, we proposed an efficient technique to reduce PAPR in OFDM system. For this technique, circular shifter used to produce K cyclic sequences from the same information sequence. These sequences XOR with K randomly generated keys, the same keys used in receiver side to detect data. The sequence with the lowest PAPR among K sequences is chosen for transmission. Side Information (SI) is coded using Hamming code and embedded into the information sequence. Computer simulation tests have been applied on BPSK and N= 64 subcarriers OFDM system with the proposed method. Moreover, this system will be evaluated under the effect of AWGN channel. The results exhibit the ability of such technique to reduce the PAPR without major effect on the system performance as compared with the conventional OFDM technique. The PAPR of OFDM signal is further reduced by 4–5 dB by this technique.

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Chen, Yuchuan. "Research on the Technology and Application of Remote Wireless Transmission of Digital Image Signal." Applied and Computational Engineering 116, no. 1 (2024): 61–66. https://doi.org/10.54254/2755-2721/116/20251725.

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With the increasing demand for remote real-time high-quality video transmission, especially in the context of large area applications of unmanned aerial vehicle (UAV) and remote location instant live broadcast, traditional wired transmission methods have been surpassed by digital transmission methods due to their superior performance in image quality, transmission distance and delay. Therefore, this study focuses on the application of digital image wireless transmission in remote scenarios such as UAVs, including key digital transmission technologies such as Orthogonal Frequency Division Multiplexing (OFDM) and Coded Orthogonal Frequency Division Multiplexing (COFDM), as well as public network link communication technologies such as 4G and 5G, by means of a literature study and a case study. It also analyzes the development of WiFi, Lightbridge and OcuSync graphics transmission systems using DJI brand products as case studies. The analysis shows that digital image wireless transmission, especially COFDM and advanced proprietary systems such as DJI's OcuSync, has significant advantages in terms of transmission distance, interference immunity, encryption techniques, and reusability. However, factors such as building obstruction, frequency interference, and weather conditions can affect the transmission quality. To mitigate these challenges, solutions are proposed, such as auxiliary signal enhancement systems, adaptive frequency hopping and software-defined radio technologies.

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Shrimali, Yanita, Janki Ballabh Sharma, and R. S. Meena. "VHDL Implementation of low power turbo coded OFDM physical layer for wireless communication." International Journal of Engineering & Technology 7, no. 4.5 (2018): 665. http://dx.doi.org/10.14419/ijet.v7i4.5.25054.

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Orthogonal Frequency Division Multiplexing (OFDM) is exceptionally favored system for rapid information transmission over remote channel. In this paper, VHDL implementation of low power turbo-coded OFDM (TCOFDM) Physical layer architecture is presented. In this architecture a low power memory-less pipelined FFT processor and Log-map turbo encoder/decoders are used to provide high throughput and lower complexity. Log-map turbo decoder provides high speed with good error correction capacity, while FFT/IFFT processor with single delay feedback (SDF) memory less architecture provide improved area and power efficiency. Proposed TCOFDM system is implemented using Xilinx ISE Design suite in the simulation results shows that the proposed scheme is having low power, high speed, high throughput and smaller area in comparison to other schemes.

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Naji Fadhel, Amneen, and Yahya Jassim Harbi. "Performance analysis of coded MIMO OFDM with subcarrier power modulation." Indonesian Journal of Electrical Engineering and Computer Science 30, no. 1 (2023): 167. http://dx.doi.org/10.11591/ijeecs.v30.i1.pp167-173.

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This study investigates a new technique known as "orthogonal frequency division multiplexing with subcarrier power modulation" (OFDM-SPM) when compounded with a "multiple-input multiple-output" (MIMO) system. This combination of the two wireless technologies offers additional benefits and characteristics, such as increased spectrum efficiency (SE), increased energy efficiency (EE), and decreased transmission latency, among others. However, as compared to a traditional MIMO-OFDM system, the system's bit error rate (BER) show degradation. In this paper, turbo code is proposed as a coding technique to enhance the system performance with three-power reallocation policies (PRPs). The simulation results show that the BER and throughput performance has gotten better, where the throughput is doubled and the BER achieves about 10 dB gain by utilizing the proposed methods and compare to the classical MIMO OFDM, which makes the system more suitable for use in future wireless systems.

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Amneen, Naji Fadhel, and Jasim Harbi Yahya. "Performance analysis of coded MIMO OFDM with subcarrier power modulation." Performance analysis of coded MIMO OFDM with subcarrier power modulation 30, no. 1 (2023): 167–73. https://doi.org/10.11591/ijeecs.v30.i1.pp167-173.

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This study investigates a new technique known as orthogonal frequency division multiplexing with subcarrier power modulation (OFDM-SPM) when compounded with a multiple-input multiple-output (MIMO) system. This combination of the two wireless technologies offers additional benefits and characteristics, such as increased spectrum efficiency (SE), increased energy efficiency (EE), and decreased transmission latency, among others. However, as compared to a traditional MIMO-OFDM system, the system's bit error rate (BER) show degradation. In this paper, turbo code is proposed as a coding technique to enhance the system performance with three-power reallocation policies (PRPs). The simulation results show that the BER and throughput performance has gotten better, where the throughput is doubled and the BER achieves about 10 dB gain by utilizing the proposed methods and compare to the classical MIMO OFDM, which makes the system more suitable for use in future wireless systems.

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Koti, Jayasudha, and Mishra B K. "SUPPRESSED CARRIER FREQUENCY DIVISION MULTIPLEXING FOR INDOOR OPTICAL WIRELESS COMMUNICATION." ICTACT Journal on Communication Technology 12, no. 4 (2021): 2557–61. http://dx.doi.org/10.21917/ijct.2021.0377.

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Asymmetrically clipped orthogonal frequency division multiplexing (ACO-OFDM) is one of the optical modulation techniques for indoor optical wireless communication systems (OWC) to enable intensity (IM) modulation and direct detection (DD). As compared to other techniques, ACO-OFDM is power efficient, bandwidth efficient and has zero impact of clipping noise. However, its high peak to average power ratio (PAPR) may lead to performance deterioration and also introduce nonlinear distortion in optical source. To further enhance its performance by reducing the PAPR, suppressed carrier frequency division multiplexing (SC-FDM) is proposed and the system is titled as interleaved coded ACO (ICACO)-OFDM. To evaluate the performance of the system, simulation has been carried out for 16-QAM, 256 subcarriers, 1000 symbols. By observing the curves generated by Complementary cumulative distribution function (CCDF) at the probability of 10-3, PAPR has been characterized. It is observed that PAPR of ICACO-OFDM is 4.98 dB less as compared to ACO-OFDM system.

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Ruggiano, Mayazzurra, Emiel Stolp, and Piet van Genderen. "Theoretical performance of reiterated LMMSE filtering and coded radar waveforms." International Journal of Microwave and Wireless Technologies 1, no. 4 (2009): 353–59. http://dx.doi.org/10.1017/s1759078709990225.

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Orthogonal frequency division multiplexing (OFDM) waveforms offer strong advantages for integrated communication and radar systems. However, they exhibit inherent high-range sidelobes after matched filtering when standard communication constellation symbols are used for the coding of the carriers. Consequently, they require filtering at the receiver that can serve for sidelobe suppression in order to avoid target masking. However, unmasking is not the only concern; it is crucial to evaluate the filtering scheme both in terms of sidelobe suppression capability and in terms of output signal-to-noise ratio. This last criterion is essential when aiming at also detecting weaker reflections. In this paper the theoretical performance of the reiterated filtering technique based on linear minimum mean square error (LMMSE) is derived and compared to the matched filter. The unmasking capabilities are relevant, but also output power figures. Complex-valued filter output peaks are also evaluated and compared to the matched filter output peaks. Moreover, the performance of reiterated LMMSE is evaluated for OFDM communication-encoded radar waveforms.

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Journal articles on the topic 'Coded orthogonal frequencydivision multiplexing'

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