Relevant bibliographies by topics / QAM-OFDM / Journal articles

To see the other types of publications on this topic, follow the link: QAM-OFDM.

Journal articles on the topic 'QAM-OFDM'

Author: Grafiati

Published: 4 June 2025

Last updated: 15 July 2025

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the top 50 journal articles for your research on the topic 'QAM-OFDM.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.

Rakhmania, Amalia Eka, Akhmad Mukhibuddin Harvinanda, Hudiono Hudiono, Aad Hariyadi, Hadiwiyatno, and Mochammad Taufik. "Analisis Kinerja Sistem Modulasi Downlink LTE dan 5G pada Kanal AWGN Berbasis MATLAB." Techné : Jurnal Ilmiah Elektroteknika 22, no. 2 (2023): 217–40. http://dx.doi.org/10.31358/techne.v22i2.341.

Full text

Abstract:

Pada penelitian ini dilakukan analisis performansi downlink LTE dan 5G dengan menggunakan MATLAB. Penelitian ini bertujuan untuk menganalisis perbandingan kinerja teknik modulasi QPSK, 16-QAM, dan 64-QAM yang digunakan pada downlink LTE dan teknik modulasi QPSK, 16-QAM, 64-QAM, dan 256-QAM pada downlink 5G yang melalui kanal AWGN untuk mengetahui nilai BER pada teknik modulasi yang digunakan. Teknik multiplexing yang digunakan adalah OFDM dan CP-OFDM untuk downlink LTE dan CP-OFDM untuk downlink 5G dengan variasi cyclic prefix yang digunakan adalah kategori ”normal”. Pada downlink LTE, kinerja modulasi QPSK lebih baik dari 16-QAM dan 64-QAM. Pada OFDM, BER QPSK diperoleh 10-19 pada Eb/No 16 dB, BER 16-QAM diperoleh 10-19 pada Eb/No 20 dB dan BER 64-QAM diperoleh 10-8 pada Eb/No 20 dB. Pada CP-OFDM, BER QPSK diperoleh 10-20 pada Eb/No 16 dB, BER 16-QAM diperoleh 10-19 pada Eb/No 20 dB dan BER 64-QAM diperoleh 10-9 pada Eb/No 20 dB. Pada downlink 5G CP-OFDM, kinerja modulasi QPSK lebih baik dari 16-QAM, 64-QAM dan 256-QAM, BER QPSK diperoleh 10-24 pada Eb/No 16 dB, BER 16-QAM diperoleh 10-23 pada Eb/No 20 dB, BER 64-QAM diperoleh 10-14 pada Eb/No 20 dB, dan BER 256-QAM diperoleh 10-7 pada Eb/No 20 dB.

APA, Harvard, Vancouver, ISO, and other styles

PAMBUDI, AFIEF DIAS, SUHARTONO TJONDRONEGORO, and HEROE WIJANTO. "Deteksi Automatis Skema Modulasi Sinyal OFDM menggunakan Ciri Statistik dan Klasifikasi PSO." ELKOMIKA: Jurnal Teknik Energi Elektrik, Teknik Telekomunikasi, & Teknik Elektronika 3, no. 2 (2015): 133. http://dx.doi.org/10.26760/elkomika.v3i2.133.

Full text

Abstract:

ABSTRAKPengenalan format modulasi dari sinyal yang dideteksi merupakan salah satu bahasan penting pada sistem intelligent receiver yang digunakan untuk aplikasi di bidang militer maupun komersial. Oleh karena itu, pada penelitian ini dilakukan klasifikasi skema modulasi pada sinyal OFDM yaitu QPSK, 16-QAM dan 64-QAM. Sinyal OFDM tersebut disimulasikan melewati kanal frequency selective fading dan additive white gaussian noise. Sistem klasifikasi yang dibuat menggunakan ekstraksi ciri statistik dan pengklasifikasi berupa diagram keputusan dengan threshold yang dioptimasi menggunakan algoritma particle swarm optimization (PSO). Pada proses klasifikasi ditambahkan sistem voting dengan skenario penggunaan jumlah simbol OFDM sebanyak 1, 5, 10, 15 dan 20. Hasil akurasi klasifikasi yang optimum didapatkan pada penggunaan lima simbol OFDM yaitu 100 %, 99 %, 96 % untuk klasifikasi QPSK, 16-QAM, 64-QAM pada minimum SNR receiver standar WiMAX IEEE 802.16e.Kata kunci: klasifikasi skema modulasi OFDM, ciri statistik, PSO.ABSTRACTModulation recognition of the detected signal is one of important topics on intelligent receiver system used for military and commercial applications. (Therefore) This research explored the classifications of the OFDM signal modulation scheme namely QPSK, 16-QAM and 64-QAM. The OFDM signal was simulated to pass through frequency selective fading channel and additive white gaussian noise. The classification system was developed using statistical feature extraction with a decision diagrams (tree diagram) as a classifier optimized by PSO algorithm. The increasing number of OFDM symbols in the classification process that applied a voting system improved the accuracy of the classification of each modulation scheme. The optimum accuracy of the classification had been obtained when five OFDM symbols were applied in the classification scenario. The accuracy was 100% for QPSK classification, 99 % for 16-QAM classification and 96 % for 64-QAM classification on the minimum SNR accepted by the receiver of a system that applied a standard WiMax IEEE 802.16e.Keywords: classification modulation schemes OFDM, statistical characteristics, PSO.

APA, Harvard, Vancouver, ISO, and other styles

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.

Full text

Abstract:

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.

APA, Harvard, Vancouver, ISO, and other styles

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.

Full text

Abstract:

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

APA, Harvard, Vancouver, ISO, and other styles

Uppal, Sabhyata, Sanjay Sharma, and Hardeep Singh. "Analytical Investigation on Papr Reduction in OFDM Systems Using Golay Codes." Journal of Electrical Engineering 65, no. 5 (2014): 289–93. http://dx.doi.org/10.2478/jee-2014-0046.

Full text

Abstract:

Abstract Orthogonal frequency division multiplexing (OFDM) is a common technique in multi carrier communications. One of the major issues in developing OFDM is the high peak to average power ratio (PAPR). Golay sequences have been introduced to construct 16-QAM and 256-QAM (quadrature amplitude modulation) code for the orthogonal frequency division multiplexing (OFDM), reducing the peak-to-average power ratio. In this paper we have considered the use of coding to reduce the peakto- average power ratio (PAPR) for orthogonal frequency division multiplexing (OFDM) systems. By using QPSK Golay sequences, 16 and 256 QAM sequences with low PAPR are generated

APA, Harvard, Vancouver, ISO, and other styles

Aksara, Deschie Tri, Alfredo Bayu Satriya, and Dodi Setiabudi. "ANALISIS PERBANDINGAN BER DAN PAPR DALAM TRANSMISI CITRA PADA SISTEM 4G LTE." Jurnal Arus Elektro Indonesia 6, no. 1 (2020): 17. http://dx.doi.org/10.19184/jaei.v6i1.16339.

Full text

Abstract:

Teknologi telekomunikasi saat ini menuntut penggunaan data rate yang tinggi dalam proses pengiriman data. OFDM merupakan teknologi multiplexing yang didasarkan pada penyebaran data yang dimodulasikan pada kecepatan data rendah. OFDM memiliki keunggulan tahan terhadap multipath delay spread, frequency selective fading, serta modulasi dan demodulasi yang efisien. Penelitian ini bertujuan untuk mengetahui karakteristik BER dan PAPR terhadap SNR dan mengetahui perbandingan kinerja teknik modulasi QPSK, 16-QAM dan 64-QAM. Penelitian dijalankan dengan melakukan simulasi pengiriman citra melalui kanal Rayleigh Fading menggunakan modulasi QPSK, 16-QAM, dan 64-QAM. Parameter SNR yang diteliti sebesar 0-16 dB. Hasil simulasi menunjukkan bahwa OFDM memiliki ketahanan noise yang lebih tinggi saat menggunakan modulasi 16-QAM dengan BER = 0 dB saar SNR 10 dB dan rata-rata nilai PAPR yang semakin meningkat dari SNR 0 dB hingga 16 dB.

APA, Harvard, Vancouver, ISO, and other styles

Zhang, Xue Yi, and Shuang Le Zhao. "Simulation and Study for the Optical OFDM Communication." Applied Mechanics and Materials 530-531 (February 2014): 729–33. http://dx.doi.org/10.4028/www.scientific.net/amm.530-531.729.

Full text

Abstract:

This paper gives a theoretical basis principle and structure of OFDM. The O-OFDM has three parts including transmitter, receiver and fiber. The main and key component is IFFT and FFT block. And then a basic direct detection optical-OFDM system (DO-OFDM) is designed and simulated by the software Optisystem. The performance of the system is viewed by the visualizer of the software compared to the RZ, OFDM and QAM modulation system. The result shows that the OFDM system is better than conventional serial modulation schemes like RZ, QAM.

APA, Harvard, Vancouver, ISO, and other styles

Hussein, A. Leftah, and N. Alminshid Huda. "Channel capacity and performance evaluation of precoded MIMO-OFDM system with large-size constellation." International Journal of Electrical and Computer Engineering (IJECE) 9, no. 6 (2019): 5024–30. https://doi.org/10.11591/ijece.v9i6.pp5024-5030.

Full text

Abstract:

Multiple input-multiple output (MIMO) is a multipath diversity exploring approach which is emerged with orthogonal frequency division multiplexing (OFDM) to produce MIMO-OFDM that is widely used in wireless communications. This paper presents a discrete Hartley transform (DHT) precoded MIMO-OFDM system over multipath frequency-selective fading channel with large-size quadrature amplitude modulation (16-QAM, 64-QAM and 256-QAM). A mathematical models for the BER and channel capacity over mutlipath fading channels are also derived in this paper. Average Bit-error-rate (BER) and channel capacity of the presented system is considered and compared with that of the traditional MIMO-OFDM. Simulation results shows that the transmission performance and channel capacity of the proposed schemes is better than that of the traditional MIMO-OFDM without a precoder.

APA, Harvard, Vancouver, ISO, and other styles

Vucic, Desimir. "Cyclic spectral analysis of OFDM/QAM modulation using stochastic matrix-based method." Facta universitatis - series: Electronics and Energetics 16, no. 3 (2003): 343–53. http://dx.doi.org/10.2298/fuee0303343v.

Full text

Abstract:

The cyclostationarity of the OFDM/QAM signals induced by the use of cyclic prefix or pulse shaping is the key to blind synchronization, channel identification and equalization in these systems. Therefore, continuous-time and discrete-time spectral correlation characterization of the pulse shaping OFDM/QAM signals is performed by a matrix-based stochastic method based on Markov chain signal representation. Exact analytical expression for the cyclic spectrum of the continuous-time OFDM/QAM signal is derived applying the proposed method, the characteristic cyclic features according to the cyclic prefix and/or pulse shaping employing are analyzed and some graphed results are presented.

APA, Harvard, Vancouver, ISO, and other styles

Leftah, Hussein A., and Huda N. Alminshid. "Channel capacity and performance evaluation of precoded MIMO-OFDM system with large-size constellation." International Journal of Electrical and Computer Engineering (IJECE) 9, no. 6 (2019): 5024. http://dx.doi.org/10.11591/ijece.v9i6.pp5024-5030.

Full text

Abstract:

Multiple input-multiple output (MIMO) is a multipath diversity exploring approach which is emerged with orthogonal frequency division multiplexing (OFDM) to produce MIMO-OFDM that is widely used in wireless communications. This paper presents a discrete Hart-ley transform (DHT) precoded MIMO-OFDM system over multipath frequency-selective fading channel with large-size quadrature amplitude modulation (16-QAM, 64-QAM and 256-QAM). A mathematical models for the BER and channel capacity over mutlipath fading channels are also derived in this paper. Average Bit-error-rate (BER) and channel capacity of the presented system is considered and compared with that of the traditional MIMO-OFDM. Simulation results shows that the transmission performance and channel capacity of the proposed schemes is better than that of the traditional MIMO-OFDM without a pre-coder.

APA, Harvard, Vancouver, ISO, and other styles

M. Sana, Ahmed, Amer T. Saeed, and Yaseen Kh. Yaseen. "Investigation on the PAPR performance of odd-bit QAM constellations for DFT spread OFDM systems." Indonesian Journal of Electrical Engineering and Computer Science 21, no. 2 (2021): 1005. http://dx.doi.org/10.11591/ijeecs.v21.i2.pp1005-1013.

Full text

Abstract:

Adaptive quadrature amplitude modulation (QAM) is a crucial scheme that enables the modern communication systems to overcome the adverse effects of channel fluctuations and maintain an acceptable spectral efficiency. In order to enhance adaptive modulation even further, adoption of odd-bit QAM constellations alongside even constellations had been suggested to improve the transmission efficiency of adaptive QAM modulation. Hence, odd-bit QAM had been extensively studied, analyzed, and tested by many researchers for various patterns, sizes, and communication systems in terms of bit error rate (BER) and peak to average power ratio (PAPR). However, the PAPR performance of odd-bit QAM constellation with single carrier transmission systems adopted in the uplink of the 4G long term evolution (LTE) standards caught almost no research interest. In this paper, the PAPR performance of both cross and rectangular odd-bit QAM constellations are investigated for DFT-S-OFDM systems. Complementary cumulative distribution functions (CCDFs) and probability density functions (PDFs) curves for PAPR are also obtained. Finally, an equation for PAPR PDF is empirically derived for odd-bit cross QAM based DFT-S-OFDM. The results show that cross odd-bit QAM outperforms the rectangular odd-bit QAM in terms of PAPR by 1.02 dB for 8-QAM and 1.3 dB for 32-QAM. This proves that cross odd-bit QAM is a better choice in terms of PAPR for DFT-S-OFDM systems.

APA, Harvard, Vancouver, ISO, and other styles

Dumari, Hise Teferi, Demissie Jobir Gelmecha, Rajeev K. Shakya, and Ram Sewak Singh. "BER and PSD Improvement of FBMC with Higher Order QAM Using Hermite Filter for 5G Wireless Communication and beyond." Journal of Electrical and Computer Engineering 2023 (January 9, 2023): 1–16. http://dx.doi.org/10.1155/2023/7232488.

Full text

Abstract:

Nowadays, multicarrier modulation schemes are being widely used in wireless communication system than single-carrier modulation techniques. Single-carrier modulation schemes are less capable of dealing with multipath fading channels than multicarrier modulation schemes, which results in lower spectral efficiency. Multicarrier modulation schemes have the ability to overcome multipath fading channels. Multicarrier modulation technique currently used in 4G technology in many countries is OFDM and it is easy for implementation, immune to interference, and provide fast data rate. However, the rising users demand on wireless communication resulted in need for further advancement of wireless communication system. The present OFDM transmission does not fulfill the requirements of 5G wireless communication system and beyond due to major limitations such as out of band emission and usage of cyclic prefix. To overcome the challenges of OFDM, different modulation schemes like Filter Bank Multicarrier with Offset-QAM, Filter Bank Multicarrier with QAM, Universal Filter Multicarrier, Filtered-OFDM, and Weighted Overlap and Added-OFDM are proposed. In this study, the Filter Bank Multicarrier with QAM using Hermite prototype filter is proposed to overcome drawbacks of OFDM and all other proposed waveforms. The performances of each multicarrier technique are analyzed based on power spectral density and bit error rate. Simulation result shows that the power spectral density of FBMC with QAM using Hermite filter resulted in 4.7 dB reduction of out of band emission compared to FBMC with QAM using PHYDYAS filter. The bit error rate is also reduced for Vehicular A, Vehicular B, Pedestrian A, and Pedestrian B channel models.

APA, Harvard, Vancouver, ISO, and other styles

.S, Ramakrishna, and Priyatam Kumar. "Bit Error Rate Performance Analysis for Various Modulation Techniques using SUI Channel in Multi-Carrier System." International Journal of Advanced Research in Computer Science and Software Engineering 7, no. 7 (2017): 419. http://dx.doi.org/10.23956/ijarcsse.v7i7.170.

Full text

Abstract:

Orthogonal Frequency Division Multiplexing (OFDM) is of the strong prospects as a future wireless communication system. Improved spectral efficiency has been found in OFDM based on DFT, has a good orthogonality but inter symbol interference (ISI) and inter carrier interference (ICI) degrade the performance. ISI and ICI can be improved by using cyclic prefix (CP). About 20% of bandwidth is consumed by CP. For preferable performance DWT based OFDM gives better outlook than DFT based OFDM.. Three advantages of using DWT are desirable signal to noise ratio, desirable data rate and below per power requirement are given by wavelet based OFDM. Comparison of performances of BER using practical channel model known as Stanford University Interim (SUI) is given in this paper. Consideration to QPSK, 4QAM, 8QAM, 16 -QAM, 32QAM, 64-QAM, 128QAM and 256 QAM has been given in modeling. Channel condition and modulation are the pre - cursors given for the selection of particular performance.

APA, Harvard, Vancouver, ISO, and other styles

Amillia, Fitri. "Analisis Kinerja Transmisi Citra Melalui Kanal Mobile To Mobile Pada Sistem Orthogonal Frequency Division Multiplexing (OFDM)." Jurnal Sains dan Teknologi Industri 15, no. 2 (2018): 131. http://dx.doi.org/10.24014/sitekin.v15i2.5107.

Full text

Abstract:

ABSTRAK Long Term Evolution (LTE) merupakan teknologi nirkabel generasi keempat (4G) memberikan layanan aplikasi multimedia berupa gambar, video dan audio berkualitas tinggi dan kecepatan internet yang tinggi menggunakan teknik transmisi Orthogonal Frequency Division Multiplexing (OFDM). Pada sistem ini menggunakan kanal mobile to mobile, dimana pemancar dan penerima serta entitas jaringan selalu bergerak. Pergerakan pengguna atau obyek di sekitarnya menyebabkan terjadinya pergeseran frekuensi (Doppler shift) yang dapat mempengaruhi kinerja sistem komunikasi. Dengan adanya permasalahan tersebut perlu dilakukan penelitian analisis kinerja transmisi citra melalui kanal mobile to mobile pada sistem OFDM. Hasil perbandingan transmisi masing-masing citra yang berbeda ukuran dalam pixel yang melalui kanal mobile to mobile menggunakan teknik modulasi 4 QAM lebih cepat mendekati nilai standard BER sebesar 10-3 daripada teknik modulasi 16 QAM. Sistem kinerja transmisi citra pada teknik modulasi 4 QAM menunjukkan kinerja transmisi lebih baik disebabkan rendahnya nilai rata-rata Eb/No 16.61 dB mampu memberikan persentase error yang cukup kecil dari pada menggunakan teknik modulasi 16 QAM nilai rata-rata Eb/No yaitu 25.71 dB. Kata Kunci: OFDM, Citra, Transmisi, kanal mobile to mobile, QAM

APA, Harvard, Vancouver, ISO, and other styles

Fauzan, Rafi Ardhan, and Theophilus Wellem. "SIMULASI SKEMA UNIVERSAL FILTERED MULTI-CARRIER (UFMC) PADA SISTEM KOMUNIKASI DIGITAL." Jurnal Indonesia : Manajemen Informatika dan Komunikasi 4, no. 3 (2023): 1380–88. http://dx.doi.org/10.35870/jimik.v4i3.340.

Full text

Abstract:

Universal Filtered Multi-Carrier (UFMC) is a multi-carrier modulation scheme that is an alternative to the Orthogonal Frequency Division Multiplexing (OFDM) scheme currently used in 4G communication systems and wireless local area networks (WLAN). The weakness of OFDM lies in the high peak-to-average power ratio (PAPR) value and out-of-band (OOB) emission which can cause interference between carriers. UFMC is one of the schemes used to overcome the weaknesses of OFDM. This research aims to study the performance of UFMC for data transmission on AWGN channel with 256-QAM, 1024-QAM, and 4096-QAM modulation. In addition, 256-point, 512-point, and 1024-point FFTs were also used to see the effect on the achievable bit error rate (BER) and PAPR value. The simulation results show that for all simulated FFT sizes and QAM values, 256-QAM produces the lowest BER value. Using a 1024-point FFT, a BER of 10-3 can be achieved with an SNR of 20 dB. The lowest PAPR value obtained in the simulation is 7.1891 dB.

APA, Harvard, Vancouver, ISO, and other styles

Quilindo Méndez, Cristian David, Eduar Fernando Hoyos Zúñiga, and Gustavo Adolfo Gómez Agredo. "Efecto de la técnica de modulación M-QAM para una infraestructura de red convergente Radio sobre Fibra (RoF)." Ingeniería y Desarrollo 39, no. 1 (2021): 66–85. http://dx.doi.org/10.14482/inde.39.1.621.3821.

Full text

Abstract:

The objective of the research is to analyze, at the simulation level, the effect of the M-Quadrature Amplitude Modulation (M-QAM) technique, in the downlink, for a converged Radio over Fiber (RoF) network infrastructure, implementing the Ortho-gonal Frequency Division Multiplexing (OFDM) technique and the Passive Optical Network architecture, with 10 Gbps capa-city (XG-PON). The evaluation of the effect of the M-QAM modulation technique was done through a pre-established simulation methodology and using the optsim sof-tware for the network model and tests. In the results of the research, the increase of the order of M-QAM modulation for a con-verged OFDM-RoF network infrastructure allows to represent more bits per symbol, however, it requires a higher transmission power. The conclusion derives in the pos-sibility of developing a robust converged OFDM-RoF network infrastructure of XG-PON type, implementing the M-QAM tech-nique, since it efficiently uses the available bandwidth.

APA, Harvard, Vancouver, ISO, and other styles

Akhtar, Jobaida, Mohammad Istiaque Reja, Md Al Amin, and Md Sahidur Rahman. "A Comprehensive Performance Analysis of MIMO-OFDM Technology Using Different MIMO Configurations and M-QAM Modulation Schemes for LTE Cellular Network." Modern Applied Science 12, no. 4 (2018): 118. http://dx.doi.org/10.5539/mas.v12n4p118.

Full text

Abstract:

MIMO-OFDM (Multiple Input Multiple Output-Orthogonal Frequency Division Multiplexing) uses multiple antennas at transmitter and receiver side to facilitate high throughput performance without needing additional bandwidth or transmission power. But frequency synchronization, Inter Carrier Interference (ICI) minimization and antenna diversity are the main challenges for MIMO-OFDM wireless technology. In this paper, a MIMO-OFDM hybrid model is designed with proper frequency synchronization and antenna diversity that minimizes ICI with improved signal strength. Using the model a comprehensive analysis in terms of Bit Error Rate (BER) performance with respect to Signal to Noise Ratio (SNR) and Bit Rate for different M-ary QAM modulation schemes and different MIMO configurations are presented over Rayleigh fading and AWGN channel. After an extensive analysis, it is found that the propose OFDM scheme shows better Bit Error rate (BER) performance for 64-QAM than any other M-ary QAM modulation schemes and the optimum MIMO configuration for this good quality performance is found to be 3×2 configuration.

APA, Harvard, Vancouver, ISO, and other styles

Zekry, Abdelhalim, Christena Ghandour, Nazmi A. Mohammed, and S. El-Rabaie. "Hybrid modulation schemes for data transmission improvement of indoor visible light communication system." International Journal of Engineering & Technology 7, no. 4 (2018): 2822. http://dx.doi.org/10.14419/ijet.v7i4.19423.

Full text

Abstract:

This work enhances the bit rate characteristics, receiver sensitivity and power requirements of multicarrier modulation schemes (MCM) for visible light communication (VLC) dimming control system at bit error rate (BER) less than 10-3. This study develops the mathematical formulation for merging pulse position modulation (PPM) and overlapping pulse position modulation (OPPM) with M-ary quadrature amplitude modulation DC-Biased optical orthogonal frequency division multiplexing (M-QAM DCO OFDM), which can achieve efficient data transmission while maintaining communication quality. These schemes are then compared with the conventional merging (i.e M-QAM DCO OFDM with pulse width modulation (PWM)). Relating to the recent advances in the field, the additional comparative study is established with the latest merging platform (i.e. M-QAM DCO OFDM with multiple pulse position modulation (MPPM)).

APA, Harvard, Vancouver, ISO, and other styles

Sarker, Sohag, Laila Arzuman Ara, Tahsin Alam, and Tarun Debnath. "Design and Analysis of MIMO F-OFDM Systems for 5G and Beyond Wireless Communications." International Journal of Recent Technology and Engineering (IJRTE) 10, no. 2 (2021): 203–10. http://dx.doi.org/10.35940/ijrte.b6274.0710221.

Full text

Abstract:

F-OFDM (Filtered-OFDM) is a flexible waveform that has been considered suitable for 5G and beyond systems for its improved spectrum utilization, moderates PAPR, low OOB emission, multiple asynchronous sub-band transmission, and high robustness to frequency selectivity. It can attain a desirable balance between frequency and time localizations for narrow bandwidths. It is also MIMO friendly. In this paper, a comprehensive design and analysis have been made to evaluate the performance of MIMO (4×4) CP-OFDM and F-OFDM systems for message bits transmission using several digital modulation techniques (16-QAM, 16-PSK, 16-DPSK, 64-QAM, 64-PSK, and 64-DPSK), RA channel coding, different windowed (Hanning, Hamming, Blackman, Blackman-Harris, RRC) sinc FIR filters for length N = 513, and MMSE signal detection technique. From MATLAB based simulation results, it is observed that F-OFDM reduces spectrum leakage thus enhances spectrum efficiency than conventional CP-OFDM. F-OFDM based system offers lower BER (Bit Error Rate) performance than CP-OFDM based system.

APA, Harvard, Vancouver, ISO, and other styles

Sohag, Sarker, Arzuman Ara Laila, Alam Tahsin, and Debnath Tarun. "Design and Analysis of MIMO F-OFDM Systems for 5G and Beyond Wireless Communications." International Journal of Recent Technology and Engineering (IJRTE) 10, no. 2 (2021): 203–10. https://doi.org/10.35940/ijrte.B6274.0710221.

Full text

Abstract:

APA, Harvard, Vancouver, ISO, and other styles

Sana, Ahmed M., Amer T. Saeed, and Yaseen Kh. Yaseen. "Investigation on the PAPR performance of odd-bit QAM constellations for DFT spread OFDM systems." Indonesian Journal of Electrical Engineering and Computer Science 21, no. 2 (2022): 1005–13. https://doi.org/10.11591/ijeecs.v21.i2.pp1005-1013.

Full text

Abstract:

Adaptive quadrature amplitude modulation (QAM) is a crucial scheme that enables the modern communication systems to overcome the adverse effects of channel fluctuations and maintain an acceptable spectral efficiency. In order to enhance adaptive modulation even further, adoption of odd-bit QAM constellations alongside even constellations had been suggested to improve the transmission efficiency of adaptive QAM modulation. Hence, odd-bit QAM had been extensively studied, analyzed, and tested by many researchers for various patterns, sizes, and communication systems in terms of bit error rate (BER) and peak to average power ratio (PAPR). However, the PAPR performance of odd-bit QAM constellation with single carrier transmission systems adopted in the uplink of the 4G long term evolution (LTE) standards caught almost no research interest. In this paper, the PAPR performance of both cross and rectangular odd-bit QAM constellations are investigated for DFT-S-OFDM systems. Complementary cumulative distribution functions (CCDFs) and probability density functions (PDFs) curves for PAPR are also obtained. Finally, an equation for PAPR PDF is empirically derived for odd-bit cross QAM based DFT-S-OFDM. The results show that cross odd-bit QAM outperforms the rectangular odd-bit QAM in terms of PAPR by 1.02 dB for 8-QAM and 1.3 dB for 32-QAM. This proves that cross odd-bit QAM is a better choice in terms of PAPR for DFT-SOFDM systems.

APA, Harvard, Vancouver, ISO, and other styles

Otsuka, Hiroyuki, Ruxiao Tian, and Koki Senda. "Transmission Performance of an OFDM-Based Higher-Order Modulation Scheme in Multipath Fading Channels." Journal of Sensor and Actuator Networks 8, no. 2 (2019): 19. http://dx.doi.org/10.3390/jsan8020019.

Full text

Abstract:

Fifth-generation (5G) mobile systems are a necessary step toward successfully achieving further increases in data rates. As the use of higher-order quadrature amplitude modulation (QAM) is expected to increase data rates within a limited bandwidth, we propose a method for orthogonal frequency division multiplexing (OFDM)-based 1024- and 4096-QAM transmission with soft-decision Viterbi decoding for use in 5G mobile systems. Through evaluation of the transmission performance of the proposed method over multipath fading channels using link-level simulations, we determine the bit error rate (BER) performance of OFDM-based 1024- and 4096-QAM as a function of coding rate under two multipath fading channel models: extended pedestrian A (EPA) and extended vehicular A (EVA). We also demonstrate the influence of phase error on OFDM-based 1024- and 4096-QAM and clarify the relationship between phase error and the signal-to-noise ratio (SNR) penalty required to achieve a BER of 1 × 10−2. This work provides an effective solution for introducing higher-order modulation schemes in 5G and beyond.

APA, Harvard, Vancouver, ISO, and other styles

Soni, G. "Performance Evaluation of OFDM Based Link Using LabVIEW 2012." Information Technologies and Control 14, no. 4 (2016): 33–38. http://dx.doi.org/10.1515/itc-2017-0015.

Full text

Abstract:

Abstract Background: Orthogonal Frequency Division Multiplexing (OFDM) has emerged as the core technology of the 4th generation mobile communication due to its capacity to combat channel fading also OFDM is highly spectral efficient. Methods/Statistical Analysis: LabVIEW 2012 is used to simulate and evaluate the performance of OFDM link. Bit Error Rate (BER) evaluation of discrete Fourier transform (DFT) based OFDM system is carried out in this work. The simulation based analysis is demonstrated by means of different modulation schemes like QPSK, 16-QAM for OFDM based wireless system. Findings: QPSK needs less SNR as compared to 16-QAM to achieve an acceptable BER Furthermore, the efficiency of OFDM increases with increase of cyclic prefix. In OFDM, ISI and ICI-interference reduced by implying cyclic prefix. Applications/Improvements: The performance analysis of orthogonal frequency division multiplexing is analyzed using LabVIEW 2012 based on performance parameters like cyclic prefix simulated at frequency of 2.4 GHz using FFT size 512, 1024.

APA, Harvard, Vancouver, ISO, and other styles

Paramonov, A. A., and V. V. Chu. "Noise immunity of QAM-OFDM signal reception using soft-decision demodulation in the presence of narrowband interference." Russian Technological Journal 12, no. 5 (2024): 17–32. http://dx.doi.org/10.32362/2500-316x-2024-12-5-17-32.

Full text

Abstract:

Objectives. The aim of this paper is to study the noise immunity of digital information transmission in systems with orthogonal frequency division multiplexing (OFDM) and quadrature amplitude modulation (QAM) of subcarriers in the presence of narrowband interference. As a way of managing this interference, the paper studies the use of a demodulator with soft outputs and subsequent decoding of the convolutional code and low-density paritycheck (LDPC) code used in the system.Methods. The results presented in the article were obtained using statistical radio engineering, mathematical statistics, encoding theory, and computer modeling.Results. The paper presents a simple method for calculating soft bit estimates in the M-point signal QAM demodulator, where M is an even power of two. A considerable amount of numerical results were obtained which show the dependence of the transmitted information bit error rate on M, as well as on the signal-to-noise ratio, signal-to-narrowband interference, and code rates.Conclusions. It can be concluded from the above results that the use of encoding with soft demodulator decisions significantly improves the noise immunity of OFDM signal reception, and enables narrowband interference to be managed efficiently. LDPC encoding is superior to convolutional encoding in increasing the noise immunity of OFDM signal reception both in the absence and in the presence of narrowband interference. Along with the use in QAM-OFDM systems, the proposed simple method for demodulating QAM signals with soft decisions can be used in any wireless communication system using M-position QAM signals, where M is 2 to an even power.

APA, Harvard, Vancouver, ISO, and other styles

Taspınar, Necmi, and Mahmoud Alhalabi. "Performance investigation of long-haul high data rate optical OFDM IM/DD system with different QAM modulations." Journal of Electrical Engineering 72, no. 3 (2021): 192–97. http://dx.doi.org/10.2478/jee-2021-0026.

Full text

Abstract:

Abstract In this paper and as a first time, we have designed and simulated 100 Gbps long haul intensity modulation and direct detection (IM/DD) optical orthogonal frequency division multiplexing (OFDM) system with high order modulation techniques by using optisystem software QAM IM/DD OFDM system was analyzed and simulated to provide high data rate for downstream signal by using dispersion compensation fiber (DCF) inside fiber link. 4-QAM OFDM system demonstrated the best BER performance compared to other simulated systems for long haul transmission distance. For comparison and investigation, important results as eye diagram, Q factor, Eb/No and BER are explained against propagation length for every simulated system.

APA, Harvard, Vancouver, ISO, and other styles

HENDRY, JANS, and ANGGUN FITRIAN ISNAWATI. "Analisis Perbandingan Kinerja Ekualisasi Zero Forcing dan MMSE pada FBMC-OQAM." ELKOMIKA: Jurnal Teknik Energi Elektrik, Teknik Telekomunikasi, & Teknik Elektronika 7, no. 3 (2019): 600. http://dx.doi.org/10.26760/elkomika.v7i3.600.

Full text

Abstract:

ABSTRAKKebutuhan layanan data pada teknologi 5G sangatlah tinggi. FBMC sebagai solusi dari kelemahan yang ada di OFDM menjadi teknologi yang digunakan pada komunikasi 5G. Pada OFDM, penggunaan ekualisasi sudah sangat banyak dilakukan penelitiannya dan menunjukkan hasil yang bervariasi tergantung dari jenis ekualisasi yang digunakan. Beberapa jenis ekualisasi yang digunakan pada modulasi OFDM antara lain Zero Forcing dan MMSE. Pada penelitian ini, beberapa variasi ekualisasi tersebut diterapkan pada FBMC dan dianalisis perbandingan kinerjanya. Penggunaan modulasi Offset-QAM yang dipadukan dengan FBMC mempunyai fungsi sebagaimana cyclic prefix pada OFDM (CP-OFDM) yakni untuk mengurangi inter symbol interference (ISI). Hasilnya menunjukkan bahwa nilai BER pada FBMC yang menggunakan ekualisasi MMSE pada SNR 5 dB mempunyai nilai sebesar 0,2941 sedangkan BER pada FBMC yang menggunakan ekualisasi ZF sebesar 0,2875. Nilai SER untuk ZF sebesar 0,5514 dan untuk MMSE sebesar 0,5391. Kapasitas kanal Hal ini menunjukkan bahwa kinerja FBMC dengan menggunakan ekualisasi MMSE lebih baik dibanding Zero Forcing.Kata kunci: FBMC, Offset-QAM, ekualisasi, Zero Forcing, MMSE ABSTRACTThe needs of data service on 5G technology is extremely necessary. FBMC as a solution over OFDM's drawbacks becomes the technology that is used in 5G communication. In OFDM technology, various equalisation methods have been used and final result highly depends on which method being used. Some of equalisation methods used in OFDM modulation are Zero Forcing (ZF) and MMSE. In this research, those equalisation methods were used on FBMC modulation and the performances were analyzed. The use of Offset-QAM modulation combined with FBMC actually functioning like Cyclic Prefix on OFDM which is to reduce Inter Symbol Interference (ISI). The result shows that BER value on FBMC that used MMSE equalisation when SNR 5 dB equals to 0.2941 whereas BER value on FBMC that used ZF equals to 0.2875. The value of SER on ZF is 0.5514 and MMSE is 0.5391. Channel Capacity calculation also shows that FBMC performance with MMSE is better than Zero Forcing.Keywords: FBMC, Offset-QAM, equalization, Zero Forcing, MMSE

APA, Harvard, Vancouver, ISO, and other styles

Fakher, Abolqassem, Falih Alnahwi, and Majid Alwan. "Performance Evaluation of OFDM System with Insufficient CP Using LMS Equalizer under Harsh Multipath Conditions." Iraqi Journal for Electrical and Electronic Engineering 15, no. 2 (2019): 122–29. http://dx.doi.org/10.37917/ijeee.15.2.13.

Full text

Abstract:

This paper presents an insufficient cyclic prefix (CP) Orthogonal Frequency Division Multiplexing (OFDM) system with equalizer whose coefficients are calculated using Least Mean Square (LMS) algorithm. The OFDM signal is passed through a channel with four multipath signals which cause the OFDM signal to be under high inter-symbol interference (ISI) and inter-carrier interference (ICI).8-QAM and 16-QAM digital modulation techniques are used to evaluate the performance of the proposed system. The simulation results have accentuated the high performance of the LMS equalizer via comparing its Bit Error Rate (BER) and constellation diagram with those of the Minimum Mean Square Error and Zero Forcing equalizers. Moreover, the results also reveal that the LMS equalizer provides BER performance close to that of the OFDM system with a hypothetical sufficient CP.

APA, Harvard, Vancouver, ISO, and other styles

M., F. Ghanim. "Performance investigation of WOFDM for 5G wireless networks." International Journal of Electrical and Computer Engineering (IJECE) 9, no. 4 (2019): 3153–58. https://doi.org/10.11591/ijece.v9i4.pp3153-3158.

Full text

Abstract:

Nowadays, emerging wireless networks scenarios such as the proposed systems for 5G is discussed widely with diverse requirements. Orthogonal Frequency Division Multiplexing (OFDM) is a conservative proposal which is used to build 5G WOFDM system (Wavelet OFDM system). The simulation of the system is initialized with BPSK then with QAM and 64-QAM the system is improved by increasing the number of levels of Discrete Wavelet Transform to five levels and finally compared with original system to prove that the it is convenient for 5G Wireless networks.

APA, Harvard, Vancouver, ISO, and other styles

Ghanim, M. F. "Performance investigation of WOFDM for 5G wireless networks." International Journal of Electrical and Computer Engineering (IJECE) 9, no. 4 (2019): 3153. http://dx.doi.org/10.11591/ijece.v9i4.pp3153-3158.

Full text

Abstract:

Nowadays, emerging wireless networks scenarios such as the proposed systems for 5G is discussed widely with diverse requirements. Orthogonal Frequency Division Multiplexing (OFDM) is a conservative proposal which is used to build 5G WOFDM system (Wavelet OFDM system). The simulation of the system is initialized with BPSK then with QAM and 64-QAM the system is improved by increasing the number of levels of Discrete Wavelet Transform to five levels and finally compared with original system to prove that the it is convenient for 5G Wireless networks.

APA, Harvard, Vancouver, ISO, and other styles

Zhou, He, Xi Fang, Song Zhang, Yunzhang Wang, Jifang Jin, and Ding Ding. "Gaussian wavelet basis expansion based phase noise suppression method for coherent optical OFDM systems." Journal of Physics: Conference Series 2700, no. 1 (2024): 012006. http://dx.doi.org/10.1088/1742-6596/2700/1/012006.

Full text

Abstract:

Abstract In this paper, we developed a phase noise suppression method based on Gaussian wavelet basis expansion (GWBE) for coherent optical orthogonal frequency-division-multiplexing (CO-OFDM) systems. Compared with traditional phase noise suppression methods, the GWBE method significantly enhances the system’s robustness to laser phase noise, providing improved phase noise suppression, especially in scenarios with high linewidth. Additionally, the method demonstrates excellent performance in 32-QAM and 64-QAM. By employing the proposed GWBE method, the impact of laser phase noise on CO-OFDM can be effectively mitigated.

APA, Harvard, Vancouver, ISO, and other styles

Kapse, Yogita Dinkar, and Shripad Pralhad Mohani. "Performance analysis of OFDM with variations in cyclic prefix and FFT lengths." Review of Computer Engineering Research 10, no. 4 (2023): 182–98. http://dx.doi.org/10.18488/76.v10i4.3551.

Full text

Abstract:

Orthogonal Frequency Division Multiplexing (OFDM) is a modern and suitable modulation strategy for commercial high-speed broadband wireless communication systems. This is because wireless services and demands have grown so quickly in recent years. While creating wireless communication, the channel environment is crucial. A square grid with identical vertical and horizontal spacing is used for the constellation points in quadrature amplitude modulation (QAM). More bits can be transferred per symbol to higher-order modulation forms. This research has looked at how Orthogonal Frequency Division Multiplexing OFDM systems perform using different modulation techniques on channels with additive white Gaussian noise (AWGN). Using MATLAB software to do an experiment with different modulation methods and parameters such as FFT length and cyclic prefix findings showed that 64-QAM modulation sends the same amount of data faster and with fewer symbols than QPSK 16-QAM. Here, the 64-QAM modulation technique performs better. An extensive literature survey has been carried out. The work done here involved working on many parameters to improve the performance of OFDM, i.e., by reducing BER, changing modulation techniques, and analyzing the trade-off between cyclic prefix length and Bit Error Rate. Compared to the existing work, the proposed system provides better performance.

APA, Harvard, Vancouver, ISO, and other styles

Wang, Jingjing, Yongtao Du, Chunhao Liang, Zhong Li, and Jing Fang. "Performance Evaluation of Highly Nonlinear Fiber (HNLF) Based Optical Phase Conjugation (OPC) in Long Haul Transmission of 640 Gbps 16-QAM CO-OFDM." Photonics 8, no. 2 (2021): 45. http://dx.doi.org/10.3390/photonics8020045.

Full text

Abstract:

This paper presents the quantitative measurement through an experimental test of 640 Gbps 16-QAM coherent-optical orthogonal frequency-division multiplexing (CO-OFDM) over 800 km optical fiber with mid-link optical phase conjugation (OPC) using highly nonlinear fiber (HNLF). The first focus is the OPC parameter optimization, including the optimization of HNLF length and signal/pump power that inputs into OPC. Four different HNLFs, as the illustrative examples, are investigated. The second focus is to investigate the effects of fiber dispersion, nonlinearity, and amplified spontaneous emission (ASE) noise on the long-haul transmission of 16-QAM CO-OFDM signal, and the OPC compensation efficiency. The performance evaluation focuses on the conversion efficiency (CE), received signal constellation, Q-factor improvement, and bit error rate (BER) at the receiver end. Such end-to-end performance evaluation is important because the 16-QAM CO-OFDM signal status is heterogeneous and the mitigation of transmission impairments to the signal is still unclear. The OPC parametric optimization is achieved experimentally using commercially available HNLFs with different scenarios and the numerical results are interpreted in conjunction with simulations.

APA, Harvard, Vancouver, ISO, and other styles

Kaushik, Vikas, and Himanshi Saini. "Comparative Examination of CO-OFDM Formats for Varied Fiber-Length and Bit Rate." Journal of University of Shanghai for Science and Technology 23, no. 07 (2021): 1058–67. http://dx.doi.org/10.51201/jusst/21/07174.

Full text

Abstract:

The use of multiple carriers in Orthogonal Frequency Division Modulation (OFDM) makes it bandwidth-efficient and suitable for modern communication such as Long-Term Evolution (LTE), Digital Subscriber Line (DSL) internet access, optical fiber communication, digital television, audio broadcasting, etc. In this paper, four modulation formats by using Coherent Optical Orthogonal Frequency Division Modulations (CO-OFDM) have been analyzed. These are Single Port Dual Polarization (SP DP) 16 QAM, Single-Port Single Polarization (SP SP) 16 QAM, Dual Port Single Polarization (DP SP) QPSK 16-QAM, and Single Port Dual Polarization (SP DP) QPSK. Operation characteristics such as Bit Error Rate (BER) versus fiber-length and BER versus bit-rate have been examined. The range of fiber length used for this investigation is from 0 Km to 1000 Km with loop count equal to 2 and the range of bit rate of operation is from 20 Gbps to 200 Gbps. The present investigation helps in determining the relative suitability of CO-OFDM formats at various bit-rates of operation for different fiber lengths.

APA, Harvard, Vancouver, ISO, and other styles

Rakhee, Gocher*1 &. Dr. Pramod Sharma2. "A REVIEW ARTICLE OF SIGNAL TO NOISE RATIO USING FREQUENCY DIVISION MULTIPLEXING WITH RICIAN CHANNEL." INTERNATIONAL JOURNAL OF ENGINEERING SCIENCES & RESEARCH TECHNOLOGY 7, no. 3 (2018): 41–45. https://doi.org/10.5281/zenodo.1189025.

Full text

Abstract:

The demand for high-speed mobile wireless communications is growing at a very fast rate. OFDM technology is a key technique for achieving the high data rate and spectral efficiency requirements for wireless communication systems. Frequency division Multiplexing (OFDM) [3–6] has emerged as a successful air-interface technique. The Frequency division Multiplexing was originally developed from the multi-carrier modulation techniques used in high Frequency military radios.  This thesis presents, a simulink based simulation system is implemented using Additive White Gaussian Noise channel (AWGN) to study the performance analysis of Bit Error rate (BER) Vs Signal to Noise ratio (SNR).  The model of OFDM with Rician fading channel using simulink in MATLAB is discussed. This model is used for performance enhancement of the OFDM with QPSK and QAM modulation schemes and channel condition.  The throughput and packet error rate are used to evaluate the performance of MAC layer with the change in physical layer parameter.  The performance analysis of different technique used in the QAM OFDM is compared by visualizing the BER vs SNR curve

APA, Harvard, Vancouver, ISO, and other styles

Jayant, Kumar Sahu*1 &. Namrata Sahayam2. "A REVIEW ON PERFORMANCE OF OPTICAL COMMUNICATION NETWORKS USING DIFFERENT MODULATION TECHNIQUE." INTERNATIONAL JOURNAL OF ENGINEERING SCIENCES & RESEARCH TECHNOLOGY 7, no. 6 (2018): 559–63. https://doi.org/10.5281/zenodo.1299118.

Full text

Abstract:

The demand for high-speed mobile wireless communications is growing at a very fast rate. OFDM technology is a key technique for achieving the high data rate and spectral efficiency requirements for wireless communication systems.  Orthogonal Frequency Division Multiplexing (OFDM) [3–6] has emerged as a successful air-interface technique. The Orthogonal frequency division Multiplexing was originally developed from the multi-carrier modulation techniques used in high Frequency military radios. This paper presents,  using Additive White Gaussian Noise channel (AWGN) and racian channel to studyand compair the performance analysis of Bit Error rate (BER) Vs Signal to Noise ratio (SNR).  The model of OFDM with Rician fading channel using simulink in MATLAB is discussed. This model is used for performance enhancement of the OFDM with QPSK and QAM modulation schemes and channel condition.  The throughput and packet error rate are used to evaluate the performance of communication with the change in physical layer parameter. The performance analysis of different technique used in the QAM OFDM is compared by visualizing the BER vs SNR curve.  

APA, Harvard, Vancouver, ISO, and other styles

Zeng, Fan Xin, Zhen Yu Zhang, and Lin Jie Qian. "Mappings from Binary Variables to QAM Symbols and Improvement of Peak Envelope Power of OFDM Systems." Applied Mechanics and Materials 644-650 (September 2014): 4205–9. http://dx.doi.org/10.4028/www.scientific.net/amm.644-650.4205.

Full text

Abstract:

This paper establishes a mapping relationship from independent binary variables to QAM symbols. By these proposed mappings square QAM constellation can be produced by binary signals rather than quaternary signals, which is advantageous to operation of those apparatuses driven only by binary signals. As one of applications of these presented mappings, we give an example to verify improvement of upper bounds of peak envelope power in an OFDM communication system employing QAM complementary sequences.

APA, Harvard, Vancouver, ISO, and other styles

Aidatul Julia, Azlina Idris, Nur Asfarina Idrus, Kaharuddin Dimyati, and Murizah Kassim. "Performance of PAPR for Different Modulation Technique Using Cluster Scrambling Codeword Shifting Technique in F-OFDM Systems." Journal of Advanced Research in Applied Sciences and Engineering Technology 31, no. 2 (2023): 255–67. http://dx.doi.org/10.37934/araset.31.2.255267.

Full text

Abstract:

Filtered-OFDM (F-OFDM) is one of the proposed 5G system candidates. In order to achieve service diversification, it must be able to support a large number of asynchronous subband transmissions. However, the transmitted signal in a multi-carrier transmission system with different subcarriers has a high peak-to-average power ratio (PAPR). Therefore, the main problem of F-OFDM systems is the high PAPR in the system, which leads to poor performance and excessive power consumption due to numerous distortions. This study introduces a technique based on codeword structure manipulation known as Cluster Scrambling Codeword (CSC) to achieve better reduction of PAPR with the evaluation of the performance of QAM and APSK modulation. This is a new formulation of the bit data sequence shifting approach that can reduce PAPR more effectively than the conventional scheme. Simulation results show that CSC with 256 QAM modulation scheme provides a PAPR reduction better than the conventional F-OFDM system.

APA, Harvard, Vancouver, ISO, and other styles

Puneeth, Kumar D. N., and N. Eshwarappa M. "An Efficient DWT-DAPM Technique for PAPR Reduction in OFDM System." International Journal of Engineering and Advanced Technology (IJEAT) 9, no. 3 (2020): 1691–93. https://doi.org/10.35940/ijeat.C5531.029320.

Full text

Abstract:

In this paper, Discrete Wavelet Transform (DWT) Orthogonal Frequency Division Multiplexing (OFDM) system is compared with Discrete Cosine Transform (DCT) and Discrete Fourier Transform (DFT) OFDM systems. The channel noise is modelled with A white Gaussian Model (AWGN), the fading is the impairment in the channel and modelled by Rayleigh fading which is frequency selective fading channel and flat fading channel. The comparisons of Peak to Average Power Ratio (PAPR) and Bit Error Rate (BER) are made using modulation techniques such as Differential Amplitude and Phase Modulation (DAPM), Quadrature Amplitude Modulation (QAM) and Pulse Amplitude Modulation (PAM). Simulation results shows that PAPR is 4.497 dB for DWT-DAPM combination, 4.684 dB for DWT-QAM combination and 6.211 dB for DWT- PAM combination at 10-3 Complementary Cumulative Distributive Function (CCDF).The performance Analysis with the combination of DFT, DCT with DAPM, QAM and PAM are also compared. The BER is 0.01816, 0.01806 at 20 dB SNR in frequency selective channel, flat fading channel for DWT-DAPM and for DWT- QAM, AWGN channel BER is 0.01765 at 20dB SNR.

APA, Harvard, Vancouver, ISO, and other styles

Kadhim, Muthanna Ali, Ali Yousif Fattah, and Atheer Alaa Sabri. "Spectral efficiency and performance improvement of coherent optical transmission system." Indonesian Journal of Electrical Engineering and Computer Science 27, no. 1 (2022): 290. http://dx.doi.org/10.11591/ijeecs.v27.i1.pp290-300.

Full text

Abstract:

This paper presents an orthogonal frequency division multiplexing (OFDM) for a long-haul optical transmission system with high-rate transferability to alleviate dispersion effects. In addition, we suggest combining polarization division multiplexing (PDM) with coherent OFDM (CO-OFDM) to increase spectral efficiency (SE). Based on OptiSystem (2021) version 18.0" software package, a 100 Gbps single-channel PDM-CO-OFDM transmission system is investigated using different modulation formats; bipolar phase keying (BPSK), quadrature phase shift keying (QPSK), Eight-Phase-Shift Keying modulators (8-PSK), and quadrature amplitude modulation (16-QAM). A 60 km span of standard single-mode fiber (SSMF) cable is employed in this investigation. The system's performance and spectral efficiency have been evaluated by comparing against the different modulation schemes. The outcomes that were got show that the BPSK modulation scheme has the longest transmission distance and requires a lesser level of optical signal to noise ratio (OSNR) at the receiver side. Concerning spectral efficiency, 16-QAM outperforms the others. Farther, the impact of employing ultra-low loss and large effective area fiber in reducing loss and nonlinear effects in the optical channel for 16-QAM modulation formats is examined. The result found that the system with advanced fiber has superior performance than the SSMF. The bit error rate (BER) of 0.033 (20% concatenated forward error correction (FEC) threshold) is used as a baseline.

APA, Harvard, Vancouver, ISO, and other styles

Kadhim, Muthanna Ali, Ali Yousif Fattah, and Atheer Alaa Sabri. "Spectral efficiency and performance improvement of coherent optical transmission system." Indonesian Journal of Electrical Engineering and Computer Science 27, no. 1 (2022): 290–300. https://doi.org/10.11591/ijeecs.v27.i1.pp290-300.

Full text

Abstract:

This paper presents an orthogonal frequency division multiplexing (OFDM) for a long-haul optical transmission system with high-rate transferability to alleviate dispersion effects. In addition, we suggest combining polarization division multiplexing (PDM) with coherent OFDM (CO-OFDM) to increase spectral efficiency (SE). Based on OptiSystem (2021) version 18.0" software package, a 100 Gbps single-channel PDM-CO-OFDM transmission system is investigated using different modulation formats; bipolar phase keying (BPSK), quadrature phase shift keying (QPSK), Eight-Phase-Shift Keying modulators (8-PSK), and quadrature amplitude modulation (16-QAM). A 60 km span of standard single-mode fiber (SSMF) cable is employed in this investigation. The system's performance and spectral efficiency have been evaluated by comparing against the different modulation schemes. The outcomes that were got show that the BPSK modulation scheme has the longest transmission distance and requires a lesser level of optical signal to noise ratio (OSNR) at the receiver side. Concerning spectral efficiency, 16- QAM outperforms the others. Farther, the impact of employing ultra-low loss and large effective area fiber in reducing loss and nonlinear effects in the optical channel for 16-QAM modulation formats is examined. The result found that the system with advanced fiber has superior performance than the SSMF. The bit error rate (BER) of 0.033 (20% concatenated forward error correction (FEC) threshold) is used as a baseline.

APA, Harvard, Vancouver, ISO, and other styles

Dr. Atul Suryavanshi. "Optimized Adaptive Huffmann Coding For Paper Reduction in OFDM Systems." International Journal of New Practices in Management and Engineering 2, no. 04 (2013): 13–18. http://dx.doi.org/10.17762/ijnpme.v2i04.23.

Full text

Abstract:

The main defect of OFDM systems is its high peak-to-average power ratio (PAPR). To decrease PAPR, Adaptive Huffman coding is essential. Encoding is transferred by two encoding techniques Huffman coding and Adaptive Huffman coding at the transmitter side. Mapping is done by QAM 16 and PSK 16.The PAPR results of Huffman and adaptive Huffman coding with QAM 16 and PSK 16 is compared. Simulation results shows that the Adaptive Huffman coding along with QAM 16 produces fruitful results in comparison with Huffman coding and adaptive Huffman coding with PSK 16.

APA, Harvard, Vancouver, ISO, and other styles

Bozic, M., A. Anastasijevic, K. Rabbi, N. Mohottige, and D. Budimir. "Joint Evaluation of I /Q Imbalance and Reconfigurable RF Filter Nonlinearity in LTE Transmitters." WSEAS TRANSACTIONS ON COMMUNICATIONS 21 (January 5, 2022): 10–13. http://dx.doi.org/10.37394/23204.2022.21.2.

Full text

Abstract:

In this paper, a joint evaluation of I/Q imbalance and reconfigurable bandpass filter nonlinearity in wireless transmitters is described. An experimental analysis of complete Orthogonal Frequency Division Multiplex (OFDM) transmitter is presented for the purpose of quantifying these nonlinearities using LTE R9 3 MHz 16 QAM and LTE R9 3 MHz 64 QAM signals.

APA, Harvard, Vancouver, ISO, and other styles

Hamlili, Heyem, Samir Kameche та Abdelhafid Abdelmalek. "SαS noise suppression for OFDM wireless communication in rayleight channel". International Journal of Electrical and Computer Engineering (IJECE) 10, № 2 (2020): 2003. http://dx.doi.org/10.11591/ijece.v10i2.pp2003-2010.

Full text

Abstract:

Orthogonal frequency division multiplexing (OFDM) is a form of multi-carrier transmission technique widely used in the modern wireless network to achieve high-speed data transmission with good spectral efficiency. However, in impulsive noise environement BER performances of these systems, originally designed for a Gaussian noise model, are much degraded. In this paper, a new symmetric-alpha-stable (SαS) noise suppression technique based conjointly on adaptive modulation, convolutional coding (AMC) and Recursive Least Square (RLS) filtering is presented. The proposed scheme is applied on OFDM system in Rayleigh fading channel. The transmissions are analyzed under different combinations of digital modulation schemes (BPSK, QPSK, 16-QAM, 64-QAM) and convolutional code rates (1/2, 2/3, 3/4). Simulation results show that our proposed hybrid technique provides effective impulsive noise cancelation in OFDM system and exhibits better BER performance.

APA, Harvard, Vancouver, ISO, and other styles

Heyem, Hamlili, Kameche Samir та Abdelmalek Abdelhafid. "SαS noise suppression for OFDM wireless communication in rayleight channel". International Journal of Electrical and Computer Engineering (IJECE) 10, № 2 (2020): 2003–10. https://doi.org/10.11591/ijece.v10i2.pp2003-2010.

Full text

Abstract:

Orthogonal frequency division multiplexing (OFDM) is a form of multicarrier transmission technique widely used in the modern wireless network to achieve high-speed data transmission with good spectral efficiency. However, in impulsive noise environement BER performances of these systems, originally designed for a Gaussian noise model, are much degraded. In this paper, a new symmetric-alpha-stable (SαS) noise suppression technique based conjointly on adaptive modulation, convolutional coding (AMC) and Recursive Least Square (RLS) filtering is presented. The proposed scheme is applied on OFDM system in Rayleigh fading channel. The transmissions are analyzed under different combinations of digital modulation schemes (BPSK, QPSK, 16-QAM, 64-QAM) and convolutional code rates (1/2, 2/3, 3/4). Simulation results show that our proposed hybrid technique provides effective impulsive noise cancelation in OFDM system and exhibits better BER performance.

APA, Harvard, Vancouver, ISO, and other styles

Shanmugasundaram, S. "Sub Carrier Analysis for QAM Modulation." Bulletin of Electrical Engineering and Informatics 6, no. 4 (2017): 354–57. http://dx.doi.org/10.11591/eei.v6i4.866.

Full text

Abstract:

Orthogonal Frequency Division Multiplexing (OFDM) based wireless data transmission system is a multi-carrier system in which single higher rate data stream can be divided into multiple lower rate data streams. Modulation and De-Modulation technique play a major role in OFDM based data transmission system. Based on Modulation technique only, the frequency transformation method and encoding and decoding methods are enabled. Effective modulation techniques called as “Quadrature Amplitude Modulation (QAM)” modulation are used to design an OFDM System. Carrier signal is one of the important signals used to modulate the original signal. Analyzing the sub-carrier signal for getting the quality of the modulated signal.

APA, Harvard, Vancouver, ISO, and other styles

S., Shanmugasundaram. "Sub Carrier Analysis for QAM Modulation." Bulletin of Electrical Engineering and Informatics 6, no. 4 (2017): 354–57. https://doi.org/10.11591/eei.v6i4.866.

Full text

Abstract:

Orthogonal Frequency Division Multiplexing (OFDM) based wireless data transmission system is a multi-carrier system in which single higher rate data stream can be divided into multiple lower rate data streams. Modulation and De-Modulation technique play a major role in OFDM based data transmission system. Based on Modulation technique only, the frequency transformation method and encoding and decoding methods are enabled. Effective modulation techniques called as “Quadrature Amplitude Modulation (QAM)”modulation are used to design an OFDM System. Carrier signal is one of the important signals used to modulate the original signal. Analyzing the sub-carrier signal for getting the quality of the modulated signal.

APA, Harvard, Vancouver, ISO, and other styles

Xue, Linlin, Jianhong Lv, and Zhongpeng Wang. "Performance Enhancement of Bit-Level XOR Compressed Image OFDM Transmission Systems." Mobile Information Systems 2022 (August 27, 2022): 1–12. http://dx.doi.org/10.1155/2022/4364706.

Full text

Abstract:

The bit error rate (BER) formula of the M-QAM system is derived under nonequally likely condition of the constellation points, from which improving the BER performance of the M-QAM system by optimizing the probability distribution of constellation points is identified. Based on the analysis, the bit-level XOR method is employed to encrypt the image data and modify the probability distribution of the constellation points. The simulation results show that bit-level XOR is helpful to obtain a better probability distribution of the 16-QAM system compared to that without bit XOR and hence can improve the BER performance of the proposed OFDM transmission system. Simulation results based on test images over the AWGN channel further confirm that the reliability of the OFDM transmission system and the reconstructed quality of the compressed image are both significantly enhanced using bit-level XOR operation.

APA, Harvard, Vancouver, ISO, and other styles

Gao, Yan, and Jie Lian. "Tolerance-Aided Interference Degradation for Optical OFDM in Power-Constrained Systems." Photonics 10, no. 11 (2023): 1206. http://dx.doi.org/10.3390/photonics10111206.

Full text

Abstract:

Optical wireless communications (OWCs) are power-efficient for providing short-range and high-speed data transmission. In this paper, we propose an interference degradation algorithm for power-constrained OWC systems when using orthogonal frequency division multiplexing (OFDM). In this algorithm, we introduce a decision tolerance at the receiver that can be optimally designed to reduce interference caused by peak power clipping distortion and decrease additive noise collected by the photodetectors. Although the recently proposed clipping-enhanced optical OFDM (CEO-OFDM) can transmit clipped information through extra signal frames, reconstructing the received signal introduces more noise. Using the proposed decision tolerance, we can determine whether the signals in the extra frame are required for data reconstruction. By optimally choosing the decision tolerance, the bit error rate (BER) performance is enhanced compared to those of DCO, ACO, and CEO-OFDM. Additionally, the proposed algorithm offers a wider dynamic modulation index range than DCO, ACO, and CEO-OFDM at the same BER. Using the tested parameters, the proposed algorithm with 64-QAM achieves a similar best BER performance as DCO, ACO, and CEO-OFDM using 32-QAM. Therefore, the proposed algorithm achieves a higher data rate than those of the other compared techniques.

APA, Harvard, Vancouver, ISO, and other styles

Sa'adah, Nihayatus, I. Gede Puja Aswara, and Amang Sudarsono. "Implementasi skema pengacakan subcarrier OFDM dengan algoritma RSA pada NI-USRP." JURNAL ELTEK 20, no. 2 (2022): 79. http://dx.doi.org/10.33795/eltek.v20i2.354.

Full text

Abstract:

Abstrak Keamanan jaringan nirkabel merupakan salah satu hal terpenting dalam sistem komunikasi. Karena sinyal dikirim dari pengirim melalui saluran nirkabel, tidak hanya penerima yang sah, tetapi juga penyadap dapat menangkap dan menyimpan sinyal informasi dengan mudah. Penelitian ini mengeksplorasi skema keamanan komunikasi nirkabel dimana skema yang digunakan adalah pengacakan subcarrier. Pemancar dan penerima harus disinkronkan untuk mengembalikan subcarrier ke posisi semula. Sistem ini menggunakan algoritma RSA sebagai sinkronisasi. Teknologi keamanan pengacakan subcarrier diimplementasikan pada sistem OFDM. Sistem OFDM diimplementasikan menggunakan perangkat USRP. Hasil yang diperoleh dari penelitian ini membuktikan bahwa teknik keamanan yang digunakan tidak menurunkan kinerja sistem, bahkan dapat mengurangi jumlah kesalahan bit akibat teknik sinkronisasi. Dengan teknik sinkronisasi algoritma RSA, dari jarak pengujian 1 meter, 2 meter, dan 5 meter. Pada jarak 1 meter didapatkan hasil terbaik dengan penurunan error bit dari 19,04% menjadi 0% pada 32-QAM dan penurunan error bit dari 28,57% menjadi 4,76% pada 64-QAM Abstract Wireless network security is one of the essential things in communication systems. Since the signal is sent from the sender through a wireless channel, the legitimate receiver and eavesdropper can easily capture and store signal information. This study explores a wireless communication security scheme where the scheme used is subcarrier randomization. The transmitter and receiver must be synchronized to return the subcarrier to its original position. This system uses the RSA algorithm as synchronization. Subcarrier randomization security is implemented in OFDM system. OFDM system is implemented using USRP. The results from this study prove that security techniques don't reduce system performance, and can even reduce the number of errors due to synchronization techniques with RSA synchronization technique, with 1meter, 2meters, and 5meters experiments. At 1meter distance is the best result with bit error drop from 19.04% to 0% on 32-QAM and a bit error drop from 28.57% to 4.76% on 64-QAM.

APA, Harvard, Vancouver, ISO, and other styles

Tanaka, Hironori, Hayato Sogo, Nobuo Iwasaki, Takanori Matsuzaki, Hiroshi Shiratsuchi, and Hiromu Gotanda. "Blind Channel Estimation for QAM-OFDM Systems." Journal of Signal Processing 18, no. 2 (2014): 77–88. http://dx.doi.org/10.2299/jsp.18.77.

Full text

APA, Harvard, Vancouver, ISO, and other styles

We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!