Articoli di riviste: "M-QAM MODULATION"

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Ahmad, Husham Jawad. "Performance Evaluation and Simulation of M-Ary Quadrature Amplitude Modulation Schemes with VisSim/Comm Software". Cihan University-Erbil Scientific Journal 3, n. 2 (20 agosto 2019): 58–63. http://dx.doi.org/10.24086/cuesj.v3n2y2019.pp58-63.

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M-ary modulation schemes are considered one of widely used digital modulation in practice because of its high efficiency in power and bandwidth. Therefore, this necessity the need to study and evaluate the performance of M-ary schemes using simulation techniques. In this paper, the performance of M-ary modulations schemes M-ary quadrature amplitude modulation (QAM) is considered. Because of its efficiency in power and bandwidth, M-ary QAM (M-QAM) is one of the widely used modulation techniques in practice. Therefore, a need for studying and evaluating the performance of QAM modulation schemes is an important task for designers. In this paper, M-QAM modulation schemes for even number of bits per symbol (16, 62, and 256-QAM) and an odd number of bits per symbol (32- and 128-QAM), over Additive White Gaussian Noise channel, are studied. A VisSim/Comm simulation[1] model for M-QAM is designed. Theoretical and simulation results for bit error ratio (BER) performance of QAM modulation schemes are obtained using VisSim/Comm software. The results are evaluated and compared.

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Ali, Ahmed K., e Ergun Erçelebi. "An M-QAM Signal Modulation Recognition Algorithm in AWGN Channel". Scientific Programming 2019 (12 maggio 2019): 1–17. http://dx.doi.org/10.1155/2019/6752694.

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Computing the distinct features from input data, before the classification, is a part of complexity to the methods of automatic modulation classification (AMC) which deals with modulation classification and is a pattern recognition problem. However, the algorithms that focus on multilevel quadrature amplitude modulation (M-QAM) which underneath different channel scenarios is well detailed. A search of the literature revealed that few studies were performed on the classification of high-order M-QAM modulation schemes such as 128-QAM, 256-QAM, 512-QAM, and 1024-QAM. This work focuses on the investigation of the powerful capability of the natural logarithmic properties and the possibility of extracting higher order cumulant’s (HOC) features from input data received raw. The HOC signals were extracted under the additive white Gaussian noise (AWGN) channel with four effective parameters which were defined to distinguish the types of modulation from the set: 4-QAM∼1024-QAM. This approach makes the classifier more intelligent and improves the success rate of classification. The simulation results manifest that a very good classification rate is achieved at a low SNR of 5 dB, which was performed under conditions of statistical noisy channel models. This shows the potential of the logarithmic classifier model for the application of M-QAM signal classification. furthermore, most results were promising and showed that the logarithmic classifier works well under both AWGN and different fading channels, as well as it can achieve a reliable recognition rate even at a lower signal-to-noise ratio (less than zero). It can be considered as an integrated automatic modulation classification (AMC) system in order to identify the higher order of M-QAM signals that has a unique logarithmic classifier to represent higher versatility. Hence, it has a superior performance in all previous works in automatic modulation identification systems.

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Giraudo, E. C., R. B. Filho e R. R. Scarabucci. "On the {m-QAM}2 modulation". IEEE Communications Letters 5, n. 10 (ottobre 2001): 426–28. http://dx.doi.org/10.1109/4234.957383.

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Zekry, Abdelhalim, Christena Ghandour, Nazmi A. Mohammed e S. El-Rabaie. "Hybrid modulation schemes for data transmission improvement of indoor visible light communication system". International Journal of Engineering & Technology 7, n. 4 (6 ottobre 2018): 2822. http://dx.doi.org/10.14419/ijet.v7i4.19423.

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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)).

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Quilindo Méndez, Cristian David, Eduar Fernando Hoyos Zúñiga e 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, n. 1 (21 ottobre 2021): 66–85. http://dx.doi.org/10.14482/inde.39.1.621.3821.

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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.

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ARYANTA, DWI, ARSYAD RAMADHAN DARLIS e WIRDA SRI FARHANI. "Simulasi Sinkronisasi Carrier pada Modulasi Digital menggunakan Matlab". ELKOMIKA: Jurnal Teknik Energi Elektrik, Teknik Telekomunikasi, & Teknik Elektronika 2, n. 2 (1 luglio 2014): 100. http://dx.doi.org/10.26760/elkomika.v2i2.100.

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ABSTRAKDalam sistem komunikasi digital, salah satu manfaat teknik pengkodean adalah sebagai efisiensi bandwidth. Pada kanal komunikasi, adanya noise akan mengganggu dan menurunkan kinerja sistem komunikasi digital. Hal ini menyebabkan terjadinya kesalahan pendeteksian sinyal pembawa, yang mengakibatkan terjadi perubahan bit atau simbol pada sisi penerima. Untuk mengurangi kesalahan deteksi, maka dibutuhkan suatu mekanisme sinkronisasi carrier di sisi penerima untuk mendapatkan data yang serupa dengan data yang dikirim. Simulasi sinkronisasi carrier pada penelitian ini menggunakan metode carrier phase recovery pada modulasi digital M-PSK dan M-QAM dengan level modulasi 4 sampai dengan 32, menggunakan software Matlab versi 7.9. Hasil pengujian sistem yang telah dilakukan pada Eb/No dengan rentang 0 hingga 30 dB menunjukkan, adanya peningkatan kinerja sistem pada modulasi M-PSK dari 0,01352 sampai dengan 0,8546, dan pada modulasi M-QAM dari 0,0256 sampai dengan 0,7867.Kata Kunci: M-PSK, M-QAM, Kanal AWGN, BER, Eb/No, Phase RecoveryABSTRACTThe digital communication systems, one of the benefits coding techniques are as bandwidth efficiency. The communication channel, the presence of noise will disrupt and degrade the performance of digital communication systems. This leads to error detection of the carrier, resulting in a change of bits or symbols at the receiver side. To reduce the detection error, there is a need carrier synchronization at the receiver side to obtain similar data with the data sent. Simulation of carrier synchronization in this study using the carrier phase recovery method in digital modulation M-PSK and M-QAM modulation with levels 4 to 32, using Matlab software version 7.9. The results of system testing has been done on the Eb / No ranging from 0 to 30 dB shows, an increase in the performance of the system on the M-PSK modulation from 0.01352 to 0.8546, and the M-QAM modulation from 0.0256 to 0 , 7867. Keywords: M-PSK, M-QAM, AWGN Channel, BER, Eb/No, Phase Recovery

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Maharani, Tamara, Muhammad Agus Zainuddin e Sritrusta Sukaridhoto. "PENGUKURAN PSNR PADA TRANSMISI VIDEO DI KANAL TERAHERTZ MENGGUNAKAN QAM MODULATION". KLIK - KUMPULAN JURNAL ILMU KOMPUTER 7, n. 2 (28 giugno 2020): 154. http://dx.doi.org/10.20527/klik.v7i2.319.

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In the current era of communication has various challenges that include the intensity of information exchange more often, the amount of information carried and the speed in exchanging information. Communication is not only in the form of text and sound but also in the form of pictures and videos. This study tries to use digital data in the form of video with the aim of providing a view of the PSNR measurement simulation. The method used is modulation of QAM 64, 256, 1024 and 4096 through terahertz channels (0.1-10 THz). Simulation results show that in QAM 64 the PSNR value is 35.2 dB to 36.6 dB. The PSNR value decreases as the M-ary increases. PSNR at 256 QAM ranges from 25.9 to 26.5 dB. PSNR in QAM 1024 is stable at magnitude 16.3 to 16.5. Whereas PSNR in QAM 4096 ranged from 15.0 to 15.25. From this study shows the greater the value of PSNR, the quality of information sent is increasingly similar. In addition, the higher the M-ary, the data carried will also be large so as to speed up the transmission time.Keywords: Terahertz, QAM, PSNR, Video, Simulation Di era saat ini komunikasi memiliki berbagai tantangan yang meliputi intesitas pertukaran informasi yang lebih sering, besarnya informasi yang dibawa dan kecepatan dalam bertukar informasi. Komunikasi tidak hanya berupa text dan suara namun juga berupa gambar dan video. Penelitian ini mencoba menggunakan data digital berupa video dengan tujuan memberikan pandangan tentang simulasi pengukuran PSNR. Metode digunakan yaitu modulasi QAM 64, 256, 1024 dan 4096 melalui kanal terahertz (0.1-10 THz). Hasil simulasi menunjukkan pada QAM 64 nilai PSNR sebesar 35.2 dB hingga 36.6 dB. Nilai PSNR menurun seiring bertambahnya M-ary. PSNR pada QAM 256 di rentang 25.9 hingga 26.5 dB. PSNR pada QAM 1024 stabil di besaran 16.3 sampai 16.5. Sedangkan PSNR pada QAM 4096 di rentang 15.0 hingga 15.25. Dari penelitian ini menunjukkan semakin besar nilai PSNR maka kualitas informasi yang dikirimkan semakin mirip. Selain itu semakin tinggi M-ary maka data yang dibawa pun juga ikut besar sehingga mempercepat waktu transimisi. Kata kunci: Terahertz, QAM,PSNR, Video, Simulasi

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Mohammed, Ali Abdulwahhab, Li Yu, Manar Al-Kali e Desheng Wang. "Analysis of Amplify-and-Forward Cooperative Networks with Nakagami-m fading Channels For MRC Diversity Combining". TELKOMNIKA Indonesian Journal of Electrical Engineering 16, n. 3 (1 dicembre 2015): 546. http://dx.doi.org/10.11591/tijee.v16i3.1646.

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In this paper we study the effect of diversity combining for Nakagami -m fading Channels in the amplify-and-forward cooperative networks.We derive the cumulative density function (CDF), probability density function (PDF) and moment generating function (MGF) for the multiple relay amplify-and-forward network with single half duplex channel maximal ratio combiner (MRC). In this network we investigate the cases of MRC at the destination, as well derive the exact Symbol Error Rate (SER) of M-ary phase-shift keying (M-PSK), and quadrature amplitude modulation (M-QAM) in Nakagami -m fading environment. We present a comparison between M-PSK and M-QAM modulation schemes in some representative scenarios where an arbitrary number of cooperative relays is considered.

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Yang, Li Ming, Jia Guo, Hong Wei Ding, Yong Wang, Hong Mei Li e Han Bai Shao. "Simulation Implementation and Analysis of the Performance of M-QAM by Using MATLAB". Applied Mechanics and Materials 610 (agosto 2014): 933–38. http://dx.doi.org/10.4028/www.scientific.net/amm.610.933.

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For the implementation of digital multimedia communication, an efficient, reliable, deterministic transmission system plays a vital role. Quadrature amplitude modulation (QAM) is commonly used in digital communication systems. We focuses on simulation and analysis of M-level QAM by using MATLAB in this paper.

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Wongroekdee, Sawitree, Kosin Chaiprathum, Virasit Imtawil e Puripong Suthisopapan. "LDPC Coded 2^m-ary QAM for Ultra High Speed Communications". Applied Mechanics and Materials 781 (agosto 2015): 45–48. http://dx.doi.org/10.4028/www.scientific.net/amm.781.45.

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Modern communication systems that employ LDPC codes and QAM modulation can achieve high speed and reliable transmission without bandwidth expansion. In this paper, the performances of LDPC codes with 2m- ary QAM at m>10, which can provide enormous bandwidth efficiency, are studied. Bit error rate performances of various combinations of LDPC codes and order of QAM are provided. From the results, the performance of LDPC coded ultra-high order QAM is excellent making this system very attractive for ultra-high speed communications.

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Ge, Qian, Qian Wang, Xiao Yan e Ling He. "Algorithms for Automatic Modulation Recognition in Wireless Monitoring Applications". Applied Mechanics and Materials 241-244 (dicembre 2012): 1772–78. http://dx.doi.org/10.4028/www.scientific.net/amm.241-244.1772.

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The paper proposes an automatic modulation recognition scheme based on instantaneous features of intercepted signals. The modulation classifier can discriminate modulations such as Amplitude Modulation (AM), Double Side Band (DSB), Single Side Band (SSB), Frequency Modulation (FM), M-ary Amplitude Shift Keying (M-ASK), M-ary Frequency Shift Keying (M-FSK), M-ary Phase Shift Keying (M-PSK) and M-ary Quadrature Amplitude Modulation (M-QAM) without any prior information. The scheme is with simple structure, computationally simpler, and suitable for real-time processing. And the recognition parameters are anti-noise, and insensitive to frequency offset, phase offset and timing error. To evaluate the performance of the scheme, several experiments with signals in Additive White Gaussian Noise (AWGN) channel were carried out in the MATLAB by varying the values of both the main modulation parameters and the signal-to-noise ratios (SNRs). The results show that the approach can achieve high recognition accuracy even at low SNR.

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Kachroo, Amit, Adithya Popuri, Mostafa Ibrahim, Ali Imran e Sabit Ekin. "Interference Spreading through Random Subcarrier Allocation Technique and Its Error Rate Performance in Cognitive Radio Networks". Sensors 20, n. 19 (7 ottobre 2020): 5700. http://dx.doi.org/10.3390/s20195700.

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In this letter, we investigate the idea of interference spreading and its effect on bit error rate (BER) performance in a cognitive radio network (CRN). The interference spreading phenomenon is caused because of the random allocation of subcarriers in an orthogonal frequency division multiplexing (OFDM)-based CRN without any spectrum-sensing mechanism. The CRN assumed in this work is of underlay configuration, where the frequency bands are accessed concurrently by both primary users (PUs) and secondary users (SUs). With random allocation, subcarrier collisions occur among the carriers of primary users (PUs) and secondary users (SUs), leading to interference among subcarriers. This interference caused by subcarrier collisions spreads out across multiple subcarriers of PUs rather than on an individual PU, therefore avoiding high BER for an individual PU. Theoretical and simulated signal to interference and noise ratio (SINR) for collision and no-collision cases are validated for M-quadrature amplitude modulation (M-QAM) techniques. Similarly, theoretical BER performance expressions are found and compared for M-QAM modulation orders under Rayleigh fading channel conditions. The BER for different modulation orders of M-QAM are compared and the relationship of average BER with interference temperature is also explored further.

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Sarfraz, Mubashar, Sheraz Alam, Sajjad A. Ghauri, Asad Mahmood, M. Nadeem Akram, M. Javvad Ur Rehman, M. Farhan Sohail e Teweldebrhan Mezgebo Kebedew. "Random Graph-Based M-QAM Classification for MIMO Systems". Wireless Communications and Mobile Computing 2022 (15 aprile 2022): 1–10. http://dx.doi.org/10.1155/2022/9419764.

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Automatic modulation classification (AMC) has been identified to perform a key role to realize technologies such as cognitive radio, dynamic spectrum management, and interference identification that are arguably pivotal to practical SG communication networks. Random graphs (RGs) have been used to better understand graph behavior and to tackle combinatorial challenges in general. In this research article, a novel modulation classifier is presented to recognize M-Quadrature Amplitude Modulation (QAM) signals using random graph theory. The proposed method demonstrates improved recognition rates for multiple-input multiple-output (MIMO) and single-input single-output (SISO) systems. The proposed method has the advantage of not requiring channel/signal to noise ratio estimate or timing/frequency offset correction. Undirected RGs are constructed based on features, which are extracted by taking sparse Fourier transform (SFT) of the received signal. This method is based on the graph representation of the SFT of the 2nd, 4th, and 8th power of the received signal. The simulation results are also compared to existing state-of-the-art methodologies, revealing that the suggested methodology is superior.

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Khair, Fauza, Dodi Zulherman e Rifani Auliana. "Software-based simulation to analyze the variation of digital modulation and atmospheric condition on the free space optic (FSO) link performance". JURNAL INFOTEL 14, n. 3 (1 agosto 2022): 214–19. http://dx.doi.org/10.20895/infotel.v14i3.758.

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Free Space Optic (FSO) is the solution for telecommunications technology that offers high data rates, wide bandwidth, and low power consumption. However, to maximize the performance of the FSO system, the modulation used should be considered in environmental conditions. This study aims to compare the performance of the FSO communication link based on digital modulation variations used in various weather conditions, including sunny, rainy, and foggy weather. This study uses two attenuation models, namely the Kim and Kruse models, with variations in transmission distance from 500 meters to 10 kilometers. Modulation variations used include QPSK, 8-PSK, 16-PSK, and 16-QAM at 10 Gbps bitrate. The simulation is accomplished using OptiSystem 17.0 software. The study results show that sunny weather (very clear) has the best visibility compared to rain and fog conditions with an attenuation value of 0.46 dB/km on the Kim and Kruse models. QPSK modulation has the best performance with a BER value of less than 1x10-12 up to a transmission distance of 8 km in sunny weather, 3 km in rainy weather (medium rain), and 800 m in foggy (moderate fog) weather. The 8-PSK modulation has a BER value of less than 1x10-12 with a range of 2000 m in sunny weather and 1500 m in rainy weather but does not meet the standards in foggy weather conditions. 16-PSK and 16-QAM modulation have above baseline BER values during rainy and foggy conditions, but 16-QAM modulation still has a BER value of less than 1x10-3 during foggy conditions at a distance of 500 m.

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Nguyen, Huu Minh, Xuan Nam Tran, Van Bien Pham e Cong Dinh Nguyen. "Low-Complexity Estimation for Spatially Modulated Physical-Layer Network Coding Systems". Wireless Communications and Mobile Computing 2018 (1 ottobre 2018): 1–13. http://dx.doi.org/10.1155/2018/6310519.

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This paper proposes a low-complexity signal estimator at the relay node for a spatially modulated physical-layer network coding system. In the considered system, the two terminal nodes use spatial modulation to transmit their signals to the relay node during the multiple access phase. Based on the channel quantization method, we propose a low-complexity estimator which can detect both antenna indices and M-QAM symbols using successive interference cancellation (SIC). Moreover, we design signal constellations for a combined signal component at the relay for arbitrary M-QAM modulation. The obtained constellations allow further reduction of the computational complexity of the estimator. Performance evaluations show that the proposed estimator can achieve near-optimal error performance while requiring significantly less computational complexity compared with the maximum-likelihood detector, particularly with high-order modulation.

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Prakasam, P., e M. Madheswaran. "Digital Modulation Identification Model Using Wavelet Transform and Statistical Parameters". Journal of Computer Systems, Networks, and Communications 2008 (2008): 1–8. http://dx.doi.org/10.1155/2008/175236.

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A generalized modulation identification scheme is developed and presented. With the help of this scheme, the automatic modulation classification and recognition of wireless communication signals with a priori unknown parameters are possible effectively. The special features of the procedure are the possibility to adapt it dynamically to nearly all modulation types, and the capability to identify. The developed scheme based on wavelet transform and statistical parameters has been used to identify M-ary PSK, M-ary QAM, GMSK, and M-ary FSK modulations. The simulated results show that the correct modulation identification is possible to a lower bound of 5 dB. The identification percentage has been analyzed based on the confusion matrix. When SNR is above 5 dB, the probability of detection of the proposed system is more than 0.968. The performance of the proposed scheme has been compared with existing methods and found it will identify all digital modulation schemes with low SNR.

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Akhtar, Jobaida, Mohammad Istiaque Reja, Md Al Amin e 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, n. 4 (30 marzo 2018): 118. http://dx.doi.org/10.5539/mas.v12n4p118.

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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.

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Apolo, Juan Andrés, Beatriz Ortega e Vicenç Almenar. "Hybrid POF/VLC Links Based on a Single LED for Indoor Communications". Photonics 8, n. 7 (2 luglio 2021): 254. http://dx.doi.org/10.3390/photonics8070254.

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A hybrid fiber/wireless link based on a single visible LED and free of opto-electronic intermediate conversion stages has been demonstrated for indoor communications. This paper shows the main guidelines for proper coupling in fiber/air/detector interfaces. Experimental demonstration has validated the design results with very good agreement between geometrical optics simulation and received optical power measurements. Different signal bandwidths and modulation formats, i.e., QPSK, 16-QAM, and 64-QAM, have been transmitted over 1.5 m polymer optical fiber (POF) and 1.5 m free-space optics (FSO). Throughputs up to 294 Mb/s using a 64-QAM signal have been demonstrated using a commercial LED, which paves the way for massive deployment in industrial applications.

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Islam, Md Matiqul, Md Ashraful Islam, Md Kamal Uddin e Sujan Chandra Roy. "Performance evaluation of polar coded neural demapper based 5G MIMO communication system by varying antenna size". Multidisciplinary Science Journal 5, n. 3 (18 maggio 2023): 2023028. http://dx.doi.org/10.31893/multiscience.2023028.

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This paper proposes a Polar-coded neural damapper based 5G multiple-input multiple-output (MIMO) system for M transmitting and N receiving antenna, operating in a flat fading environment. MIMO is a spatial diversity scheme to improve channel performance and mitigate troubling fading issues in urban environments. A neural network-based smart demapper is considered instead of traditional demapper to improve the system's performance. Researchers have recently focused on developing complex neural network (NN)-based demapper on generating soft information for each transmitted bit. Neural demapper also increases spectral efficiency, meaning a symbol-to-bit demapper with higher complexity. This work considers a Polar-coded MIMO 5G communication system with 2×3, 2×4, 4×6 and 4×16 transmitting and receiving antennas, respectively, to evaluate the system performance under QAM modulation (4-QAM, 16-QAM, 256-QAM) techniques. It is evident from the simulated result that our proposed system performs better for lower-order modulation techniques with an increase in the number of transmitting and receiving antenna.

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Yang, Zhuwen, e Guofa Cai. "Design of a New Non-Coherent Cross-QAM-Based M-ary DCSK Communication System". Electronics 11, n. 19 (29 settembre 2022): 3128. http://dx.doi.org/10.3390/electronics11193128.

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In this paper, a new non-coherent cross-quadrature amplitude modulation (XQAM)-based M-ary differential chaos shift keying (XQAM-MDCSK) system is proposed. In such a system, an autocorrelator is adopted at the receiver to obtain the channel compensation value. This framework can be extended to various amplitude phase shift keying-based MDCSK systems, such as star QAM-based MDCSK (star QAM-MDCSK) and square QAM-based MDCSK (SQAM-MDCSK) systems. Moreover, the bit error rate (BER) expression of the proposed XQAM-MDCSK system is derived over a multipath Rayleigh fading channel. Results show that the proposed XQAM-MDCSK system can achieve better BER performance and a lower peak-to-average power ratio (PAPR) compared to the star QAM-MDCSK system. Furthermore, we also show that the performance of the proposed system can be close to that of a system with perfect channel state information (CSI).

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Quan, Zhi, Jiyu Luo, Hailong Zhang e Li Jiang. "Efficient Massive MIMO Detection for M-QAM Symbols". Entropy 25, n. 3 (21 febbraio 2023): 391. http://dx.doi.org/10.3390/e25030391.

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Massive multiple-input multiple-output (MIMO) systems significantly outperform small-scale MIMO systems in terms of data rate, making them an enabling technology for next-generation wireless systems. However, the increased number of antennas increases the computational difficulty of data detection, necessitating more efficient detection techniques. This paper presents a detector based on joint deregularized and box-constrained dichotomous coordinate descent (BOXDCD) with iterations for rectangular m-ary quadrature amplitude modulation (M-QAM) symbols. Deregularization maximized the energy of the solution. With the box-constraint, the deregularization forces the solution to be close to the rectangular boundary set. The numerical results demonstrate that the proposed detector achieves a considerable performance gain compared to existing detection algorithms. The performance advantage increases with the system size and signal-to-noise ratio.

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Khatoon, A., e M. S. Rahman. "Symbol Error Performance Analysis and Comparison Between Alamouti and MRRC Diversity Combining Scheme for Wireless Communication". Journal of Scientific Research 2, n. 1 (25 dicembre 2009): 54–66. http://dx.doi.org/10.3329/jsr.v2i1.3000.

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The symbol error performance of a wireless communication system is analyzed using diversity combining scheme in Rayleigh fading channels. The performance of the system is compared using Alamouti scheme and maximal-ratio receiver combining (MRRC) scheme. The performance results of the system are evaluated by numerical computation and by simulation using MATLAB. A detailed analysis and exact (closed-form) expressions of the probability of error of the wireless communication systems in Rayleigh fading channels are provided for both M-ary phase-shift keying (M-PSK) and M-ary quadrature amplitude modulation (M-QAM) schemes. Monte Carlo simulation shows exact match with the theoretical results. Keywords: Alamouti scheme; M-PSK; M-QAM; MRRC; Symbol error probability (SEP). © 2010 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. DOI: 10.3329/jsr.v2i1.3000 J. Sci. Res. 2 (1), 54-66 (2010)

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Gao, Yuliang, Alan Pak Tao Lau e Chao Lu. "Modulation-Format-Independent Carrier Phase Estimation for Square M-QAM Systems". IEEE Photonics Technology Letters 25, n. 11 (giugno 2013): 1073–76. http://dx.doi.org/10.1109/lpt.2013.2259226.

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Zhu, Zhechen, Muhammad Waqar Aslam e Asoke K. Nandi. "Genetic algorithm optimized distribution sampling test for M-QAM modulation classification". Signal Processing 94 (gennaio 2014): 264–77. http://dx.doi.org/10.1016/j.sigpro.2013.05.024.

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25

Marriwala, Nikhil, Gnana Kousalya C., B. Rajasekar, N. M. Nandhitha, Ashu Gautam e Aarti Sangwan. "Novel Real-Time Decision-Based Carrier Tracking for Software-Defined Radios Using M-ARY QAM Modulation". International Journal of Decision Support System Technology 15, n. 1 (3 febbraio 2023): 1–31. http://dx.doi.org/10.4018/ijdsst.317332.

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Abstract (sommario):

In this paper, a scalable and real-time decision-based carrier tracking for software defined radio (SDR) for M-ary QAM modulation has been proposed and tested in real-time using the universal software radio peripheral (USRP)-2922. The proposed system provides real-time decision-based carrier tracking for improved efficiency and performance. The real-time transfer of data has been done using the USRP-2922 hardware using the M-ary QAM modulation scheme for data transmission. The novelty of the proposed system is that one can transfer random data (binary bits), text or an image which can be encoded using the desired forward error correction codes (FEC) namely the convolution coding/Viterbi soft decision decoding and the turbo coding/decoding. The proposed novel SDR transceiver system with real-time decision-based carrier tracking shows an improved performance for different parameters such as the bit error rate (BER) and signal to noise ratio (Eb/No).

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Combi, Lorenzo, Alberto Gatto, Pierpaolo Boffi, Umberto Spagnolini e Paola Parolari. "Optical Multilevel Pulse Width Modulation for Analog Mobile Fronthaul". Photonics 5, n. 4 (23 novembre 2018): 49. http://dx.doi.org/10.3390/photonics5040049.

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Abstract (sommario):

The evolution of radio access networks is towards a centralized architecture (C-RAN), with massive antenna deployments and large radio-frequency bandwidths. In the next future, traditional optical transport technologies based on digital radio over fiber will no longer be able to support the mobile fronthaul traffic connecting antennas hosted at remote radio units and centralized baseband units. Analog radio over fiber can be selected to support the mobile fronthaul (MFH) network and, in particular, pulse width modulation (PWM) is a viable alternative for analog signal transport. In order to increase the MFH spectral efficiency, we propose to exploit multilevel PWM (M-PWM) in a wavelength division multiplexing-passive optical network (WDM-PON) network, comparing its performance with a conventional 2-level PWM solution. Experimental results show successful transmission over 7.5-km standard single mode fiber (SSMF) of up to 16 aggregated LTE-like 20-MHz signals with 64-QAM on each subcarrier, while up to eight aggregated LTE-like 20-MHz signals with 256-QAM could be supported. M-PWM thus allows either using higher order modulation formats or aggregating a higher number of LTE channels.

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Marriwala, Nikhil, O. P. Sahu e Anil Vohra. "Performance Analysis of Multiple FEC Channel Coding Algorithms for Software Defined Radio Using Quadrature Amplitude Modulation". International Journal of Applied Metaheuristic Computing 7, n. 2 (aprile 2016): 1–15. http://dx.doi.org/10.4018/ijamc.2016040101.

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Abstract (sommario):

This paper describes the development of a Software Defined Radio (SDR)-based Transceiver simulation model using Quadrature Amplitude Modulation (QAM) Scheme and analyze its performance using Forward Error Correction (FEC) channel coding algorithms namely the Convolution and the Turbo Codes. This model efficiently evaluates the performance of high data rate multi array M-QAM, schemes. The performance of these FEC codes is evaluated when the system is subjected to noise and interference in the channel. In this design Additive White Gaussian Noise (AWGN) channel has been considered. The design is analyzed using Bit Error Rate (BER) and Signal to Noise Ratio (SNR) for different M-QAM techniques. The simulation results give a possible solution for future SDR systems which may be used in various wireless communication systems. An experimental result shows that the QAM transceiver achieves the transmission of data at high level accurately. FEC Channel coding scheme is used wherever the re-transmission of the data is not feasible. On the receiver side, this channel coded signal is decoded in order to get back the original data even if the channel coded signal undergoes some interference from the noise in the transmission medium. The Performance is then analyzed in terms of BER for Convolution Coding and Turbo Coding algorithm at a particular value of SNR in LabVIEW graphical programming. Finally, comparison has been drawn based on different parameters between the existing SDR system and the proposed design in this paper to analyze and highlight the effectiveness of the proposed SDR design.

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Talha, Muhammad, Mubashar Sarfraz, Atta Rahman, Sajjad A. Ghauri, Rami M. Mohammad, Gomathi Krishnasamy e Mariam Alkharraa. "Voting-Based Deep Convolutional Neural Networks (VB-DCNNs) for M-QAM and M-PSK Signals Classification". Electronics 12, n. 8 (18 aprile 2023): 1913. http://dx.doi.org/10.3390/electronics12081913.

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Abstract (sommario):

Automatic modulation classification (AMC) using convolutional neural networks (CNNs) is an active area of research that has the potential to improve the efficiency and reliability of wireless communication systems significantly. AMC is the approach used in a communication system to detect the type of modulation format at the receiver end. This paper proposes a voting-based deep convolutional neural network (VB-DCNN) for classifying M-QAM and M-PSK signals. M-QAM and M-PSK signal waveforms are generated and passed through the fading channel in the presence of additive white Gaussian noise (AWGN). The VB-DCNN extracts features from the input signal through convolutional layers, and classification is performed on these features. Multiple network instances are trained on different subsets of training data in the VB-DCNN. A network instance predicts the input signal during testing. Based on the votes, the final prediction is made. Different simulation experiments are carried out to analyze the performance of the trained network, and the DCNN is designed with the Deep Neural Network Toolbox in MATLAB. The generated frames are divided into training, validation, and test datasets. Lastly, the classification accuracy of the trained network is determined using test frames. The proposed model’s accuracy is near to 100% at lower SNRs. The simulation results show the superiority of the proposed VB-DCNN compared to existing state-of-the-art techniques.

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Wang, Qiong, Youzhi Wu, Xiaole Du e Zhijie Yin. "A low complexity detection algorithm for m-QAM in spatial modulation systems". IOP Conference Series: Earth and Environmental Science 69 (giugno 2017): 012150. http://dx.doi.org/10.1088/1755-1315/69/1/012150.

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30

Suryawanshi, Rajashree, P. Kavipriya e B. P. Patil. "A Novel Modulation Scheme of 8x8 MIMO in Industry 4.0". Journal of Cases on Information Technology 23, n. 3 (luglio 2021): 1–10. http://dx.doi.org/10.4018/jcit.20210701.oa1.

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Abstract (sommario):

A key component in the usage of Industry 4.0 arrangements is the up and coming age of system network, LTE/LTE advanced today, and 5G, later on. Industry 4.0 is conveying private LTE arranges today, as they trust it will give them an upper hand and a solid head start when 5G opens up. LTE uses multiple input multiple output (MIMO), a promising technique to accomplish the necessary data rate. This article presents consequences of 8x8 MIMO framework in fading channel utilizing V-BLAST by means of zero-forcing (ZF) with standard ZF. The relative investigation in the fading channel on account of symbol error proves V-BLAST by means of ZF has predominant execution than standard ZF finder. In addition to this, in order to support adaptive modulation, various M-QAM modulation schemes for these detectors are compared. This comparison shows 128-QAM performs superiorly to staying two. This investigation is carried out to help utilization of MIMO in LTE to support Industry 4.0.

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Cordeiro Jr, Joel E., Marcelo S. Alencar, Marina V. Yashina e Alexander G. Tatashev. "Effect of Epidemic Interference on the Performance of M-ASK, M-PSK and M-QAM Modulation Schemes". Journal of Communications Software and Systems 17, n. 4 (2021): 358–65. http://dx.doi.org/10.24138/jcomss-2021-0179.

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32

Qin, Dong, Yuhao Wang e Tianqing Zhou. "Average SEP of AF Relaying in Nakagami-m Fading Environments". Wireless Communications and Mobile Computing 2018 (2018): 1–7. http://dx.doi.org/10.1155/2018/6581827.

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Abstract (sommario):

This paper is devoted to an investigation of an exact average symbol error probability (SEP) for amplify and forward (AF) relaying in independent Nakagami-m fading environments with a nonnegative integer plus one-half m, which covers many actual scenarios, such as one-side Gaussian distribution (m=0.5). Using moment generating function approach, the closed-form SEP is expressed in the form of Lauricella multivariate hypergeometric function. Four modulation modes are considered: rectangular quadrature amplitude modulation (QAM), M-ary phase shift keying (MPSK), M-ary differential phase shift keying (MDPSK), and π/4 differential quaternary phase shift keying (DQPSK). The result is very simple and general for a nonnegative integer plus one-half m, which covers the same range as integer m. The tightness of theoretical analysis is confirmed by computer simulation results.

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T, Jaya, M. Monisha, M. Meena e C. Sharanya. "Improvement of bit error rate performance of MC-CDMA system by using adaptive digital modulation schemes". International Journal of Engineering & Technology 7, n. 3.3 (8 giugno 2018): 663. http://dx.doi.org/10.14419/ijet.v7i2.33.14863.

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Abstract (sommario):

In Wireless Communication, the transmission channel suffers due to multipath propagation and channel dispersion due to Inter Symbol Interference (ISI), thereby degrades the system performance greatly. Future communication requires high data rate and effective utilization of bandwidth. Hence, there is a need to improve the Bit Error Rate (BER). The proposed work is Adaptive Modulation (AM), combined with Multi Carrier Code Division Multiple Access (MC-CDMA) based transmission system. It is a promising way to increase the data rate and it uses bandwidth in a efficient manner. The Adaptive Modulation based MC-CDMA systems applied to a wide-area environment, can achieve high data rate up to 100Mbps. In this paper M-ary PSK, M-ary QAM and M-ary CPM modulation techniques are used. The Adap-tive modulation based MC-CDMA systems perform well for around 10 number of users. As a whole, the adaptive MC-CDMA system is found to give the optimum BER performance of given digital modulation schemes for fourth generation environment.

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Walenczykowska, M., e A. Kawalec. "Type of modulation identification using Wavelet Transform and Neural Network". Bulletin of the Polish Academy of Sciences Technical Sciences 64, n. 1 (1 marzo 2016): 257–61. http://dx.doi.org/10.1515/bpasts-2016-0028.

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Abstract (sommario):

Abstract Automatic recognition of the signal modulation type turned out to be useful in many areas, including electronic warfare or surveillance. The wavelet transform is an effective way to extract signal features for identification purposes. In this paper there are M-ary ASK, M-ary PSK, M-ary FSK, M-ary QAM, OOK and MSK signals analysed. The mean value, variance and central moments up to five of continuous wavelet transform (CWT) are used as signal features. The principal component analysis (PCA) is applied to reduce a number of features. A multi-layer neural network trained with backpropagation learning algorithm is considered as a classifier. There are two research variants: interclass and intraclass recognition with a wide range of signal-to-noise ratio (SNR).

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35

Kumngern, Montree, Thanat Nonthaputha e Fabian Khateb. "Arbitrary Waveform Generators Using Current-Controlled Current Conveyor Transconductance Amplifier and Current Conveyor Analog Switches". Journal of Circuits, Systems and Computers 28, n. 11 (ottobre 2019): 1950179. http://dx.doi.org/10.1142/s0218126619501792.

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Abstract (sommario):

This paper presents a new amplitude modulation (AM), frequency modulation (FM), amplitude shift keying (ASK), frequency shift keying (FSK), phase shift keying (PSK) and quadrature amplitude modulation (QAM) waveform generators using current current-controlled conveyor transconductance amplifier (CCCTA) and current conveyor analog switches (CCASs). The CCCTA around with capacitors and resistors are used to generate high-frequency carrier which is worked as a quadrature oscillator. The oscillating frequency of oscillator can be controlled using the bias current of CCCTA, therefore FM and FSK waveforms can be obtained by applying information signal through the bias current of CCCTA. Unlike previous waveform generators, proposed circuit uses second generation current conveyor (CCII) to work as CCAS and AM, ASK, PSK and QAM waveforms can be obtained by putting information signals to control switches that realized using CCIIs. The proposed circuit has been simulated using 0.18[Formula: see text][Formula: see text]m CMOS [Formula: see text]-well process from TSMC. The simulation results are used to confirm workability of the proposed circuit.

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Marey, Amr, Mohamed Marey e Hala Mostafa. "Novel Deep-Learning Modulation Recognition Algorithm Using 2D Histograms over Wireless Communications Channels". Micromachines 13, n. 9 (17 settembre 2022): 1533. http://dx.doi.org/10.3390/mi13091533.

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Abstract (sommario):

Modulation recognition (MR) has become an essential topic in today’s wireless communications systems. Recently, convolutional neural networks (CNNs) have been employed as a potent tool for MR because of their ability to minimize the feature’s susceptibility to its surroundings and reduce the need for human feature extraction and evaluation. In particular, these investigations rely on the unrealistic assumption that the channel coefficient is typically one. This motivates us to overcome the previous constraint by providing a novel MR suited to fading wireless channels. This paper proposes a novel MR algorithm that is capable of recognizing a broad variety of modulation types, including M-ary QAM and M-ary PSK, without enforcing any restrictions on the modulation size, M. The analysis has shown that each modulation choice has a distinct two-dimensional in-phase quadrature histogram. This property is beneficially utilized to design a convolutional neural-network-based MR algorithm. When compared to the existing techniques, Monte Carlo simulations demonstrated the success of the proposed design.

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Yang, Li Ming, Jia Guo, Hong Wei Ding, Yong Wang e Yi Fan Zhao. "Simulation Implementation and Analysis of the OFDM Modulated by MPSK and M-QAM". Applied Mechanics and Materials 543-547 (marzo 2014): 2221–24. http://dx.doi.org/10.4028/www.scientific.net/amm.543-547.2221.

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Abstract (sommario):

Simulated for OFDM system modulated by 16PSK, 16QAM and 64QAM, and then we compared and analyzed their performance in the Rayleigh channel and 2 paths Rayleigh channel. Simulation results show that under the same conditions, Bit Error Rate (BER) of MQAM modulation system is lower than the same order MPSKs

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38

Kulikov, G. V., e A. A. Lelyukh. "Influence of amplitude and phase imbalance of quadratures on the noise immunity of coherent reception of signals with quadrature amplitude modulation". Russian Technological Journal 9, n. 1 (3 marzo 2021): 29–37. http://dx.doi.org/10.32362/2500-316x-2021-9-1-29-37.

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Abstract (sommario):

Quadrature amplitude modulation (QAM) is used for high-speed information transmission in many radio systems and, in particular, in DVB-S and DVB-S2/S2X digital satellite television systems. A receiver included as a part of the transmitting equipment of such systems has a block for the formation of quadrature oscillations used as a reference for signal demodulation. Due to hardware instabilities, amplitude and phase errors may occur, which leads to quadratures imbalance. These inaccuracies cause additional errors in the received signal demodulation. This can significantly degrade the noise immunity of the reception. The paper investigates the influence of amplitude and phase errors in the formation of quadrature oscillations (imbalance of quadratures) on the noise immunity of coherent reception of QAM signals. Using the methods of statistical radio engineering the parameters of the distributions of processes in the receiver are obtained, and the probability of a bit error is estimated. The dependences of the bit error probability on the amplitude unbalance factor, on the phase error of quadrature formation and on signal-to-noise ratio are obtained. It is shown that the amplitude imbalance of the quadratures leads to a significant decrease in the noise immunity of QAM signals reception at M ≥ 16. The acceptable amplitude deviation in this case can be considered to be equal to 5%. At M= 4, the amplitude imbalance in a wide range of values practically does not affect the noise immunity. The phase imbalance of quadratures markedly affects the noise immunity of coherent reception of QAM signals. The permissible phase error is no more than 0.05 rad (3 degrees). As the signals positionality increases, this influence also increases.

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F. Mohammed, Hassan, e Ghanim A. Al-Rubaye. "BER PERFORMANCE ANALYSIS OF 4QAM/OFDM OVER DIFFERENT SCENARIOS OF LAPLACE FADING CHANNEL." Journal of Engineering and Sustainable Development 25, Special (20 settembre 2021): 1–26. http://dx.doi.org/10.31272/jeasd.conf.2.1.4.

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Abstract (sommario):

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

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Ng, Wai Pang, Nageswara Lalam, Xuewu Dai, Qiang Wu, Yong Qing Fu, Peter Harrington, Nathan J. Gomes e Chao Lu. "Integrating Radio-Over-Fiber Communication System and BOTDR Sensor System". Sensors 20, n. 8 (15 aprile 2020): 2232. http://dx.doi.org/10.3390/s20082232.

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Abstract (sommario):

In this paper, we propose and experimentally demonstrate for the first time, the integration of a radio-over-fiber (RoF) communication system and a Brillouin optical time-domain reflectometry (BOTDR) distributed sensor system using a single optical fiber link. In this proof-of-concept integrated system, the communication system is composed of three modulation formats of quadrature phase-shift keying (QPSK), 16-quadrature amplitude modulation (16-QAM) and 64-QAM, which are modulated onto an orthogonal frequency division multiplexing (OFDM) signal. Whereas, the BOTDR sensor system is used for strain and/or temperature monitoring over the fiber distance with a spatial resolution of 5 m using a 25 km single-mode silica fiber. The error vector magnitude (EVM) is analyzed in three modulation formats in the presence of various BOTDR input pump powers. Using QPSK modulation, optimized 18 dBm sensing and 10 dBm data power, the measured EVM values with and without bandpass filter are 3.5% and 14.5%, respectively. The proposed system demonstrates a low temperature measurement error (±0.49 °C at the end of 25 km) and acceptable EVM values, which were within the 3GPP requirements. The proposed integrated system can be effectively applied for practical applications, which significantly reduces the fiber infrastructure cost by effective usage of a single optical fiber link.

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Yu, Wenjuan, Haowei Jia e Leila Musavian. "Joint Adaptive M-QAM Modulation and Power Adaptation for a Downlink NOMA Network". IEEE Transactions on Communications 70, n. 2 (febbraio 2022): 783–96. http://dx.doi.org/10.1109/tcomm.2021.3124947.

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Song, Hengguo, Qimei Cui, Huiling Zuo, Xuefei Zhang e Hui Wang. "Variable rate and power M-QAM for DPS/DPB CoMP with adaptive modulation". Transactions on Emerging Telecommunications Technologies 28, n. 11 (18 aprile 2017): e3185. http://dx.doi.org/10.1002/ett.3185.

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Nofal, Abdul-Nasser, Abdel-Nasser Assimi e Yasser M. Jaamour. "Joint Power Allocation and Bit-Loading for Multicarrier Systems with Discrete Modulation". Mathematical Modelling of Engineering Problems 8, n. 4 (31 agosto 2021): 626–34. http://dx.doi.org/10.18280/mmep.080416.

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Abstract (sommario):

In this paper, we propose two algorithms for joint power allocation and bit-loading in multicarrier systems using discrete modulations. The objective is to maximize the data rate under the constraint of a suitable Bit Error Rate per subcarrier. The first algorithm is based on the Lagrangian Relaxation of the discrete optimization problem in order to find an initial solution. A discrete solution is found by bit truncation followed by an iterative modulation adjustment. The second algorithm is based on Discrete Coordinate Ascent framework with iterative modulation increment of one selected subcarrier at each iteration. A simple cost function related to the power increment per bit is used for subcarrier selection. A sub-optimal low complexity Discrete Coordinate Ascent algorithm is proposed that overcome the limitations of the Hughes-Hartogs algorithm. The Lagrangian Relaxation algorithm provides a suboptimal solution for non-coded system using M-QAM modulations, whereas the low complexity Discrete Coordinate Ascent algorithm provides a near optimal solution for coded as well as for non-coded system using an arbitrary modulation set. Numerical results show the efficiency of the proposed algorithms in comparison with traditional methods.

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Arafa, T., W. Sauer-Greff e R. Urbansky. "Improving the performance of BICM-ID and MLC systems with different FEC codes". Advances in Radio Science 11 (4 luglio 2013): 87–93. http://dx.doi.org/10.5194/ars-11-87-2013.

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Abstract (sommario):

Abstract. In bandwidth limited communication systems, the high data rate transmission with performance close to capacity limits is achieved by applying multilevel modulation schemes in association with powerful forward error correction (FEC) coding, i.e. coded modulation systems. The most important practical approaches to coded modulation systems are multilevel coding with multistage decoding (MLC/MSD) and bit interleaved coded modulation with iterative demapping and decoding (BICM-ID). Multilevel modulation formats such as M-QAM, which can be used as a part of coded modulation systems, have the capability of multilevel protection. Based on this fact, we investigate the methods to improve the performance of BICM-ID using multiple interleavers with different binary channel coding schemes such as convolutional codes, turbo codes and low-density parity-check (LDPC) codes. Moreover, an MLC system with parallel decoding on levels (PDL) at the receiver is considered. In our contribution, we propose to design the individual coding schemes using the extrinsic information transfer (EXIT) charts for individual bit levels in the constellation. Our simulation results show that the BICM-ID systems, taking into account different bit-level protections, can provide an improvement of 0.65 dB, 1.2 dB and 1.5 dB for 256-QAM with turbo, LDPC and convolutional codes, respectively. On the other hand, MLC systems with PDL designed using EXIT charts for individual bit levels can slightly improve the performance and eliminate the error floor compared to the systems with MSD.

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Iyiola, Akintunde O., Ayokunle D. Familua, Theo G. Swart e Thokozani Shongwe. "Modeling of Burst Impulse Noise Errors in an In-House M-QAM-Based Power Line Communications Channel Using the Fritchman–Markov Model". Sensors 23, n. 15 (25 luglio 2023): 6659. http://dx.doi.org/10.3390/s23156659.

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Abstract (sommario):

Within the power line communication (PLC) network, a large number of electronic devices are connected, and environmental factors can cause unusual behavior, leading to high-amplitude impulse noise in the received signal and, as a result, packet losses and burst errors in the data that are sent. Burst errors make it difficult to send data over power line channels efficiently and accurately. Analyzing error patterns with intelligent techniques can provide valuable insights into data transmission efficiency, enhance transmission quality, and optimize PLC systems. This research proposes a three-state Fritchman–Markov chain-based power line communication error model and develops a software-defined PLC system. The goal is to analyze and model the system’s statistical error process. The PLC system’s fundamental error pattern is deduced from the transmission and reception of data on our software-defined (SD) PLC platform. The system is designed with multi-state quadrature amplitude modulation (M-QAM) data transmission and reception techniques. An error pattern consisting of 50,000 bits is obtained by comparing the bits transmitted with those received using the in-house M-QAM-based PLC transceiver system. The error characteristics of the newly developed M-QAM SD-PLC system are precisely modeled using the error model. Examining the burst error statistics of the reference error sequences of the SD-PLC system and the three-state Fritchman–Markov error model reveals striking similarities. According to the results, the error model accurately represents the error characteristics of the developed M-QAM SD-PLC system. The proposed three-state Fritchman–Markov chain-based error model for PLC has the potential to provide a comprehensive understanding of the error process in PLC. Additionally, it can assess error control strategies with less computational complexity and a shorter simulation time.

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ARYANTA, DWI. "Analisis Kinerja Subscriber Station WiMAX di Urban Area Bandung". ELKOMIKA: Jurnal Teknik Energi Elektrik, Teknik Telekomunikasi, & Teknik Elektronika 1, n. 2 (1 luglio 2013): 128. http://dx.doi.org/10.26760/elkomika.v1i2.128.

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Abstract (sommario):

ABSTRAKTeknologi komunikasi wireless semakin pesat mengalami perkembangan. WiMAX merupakan suatu teknologi broadband yang didukung oleh standar IEEE 802.16d (802.16-2004) yang mampu memberikan layanan data berkecepatan tinggi hingga 75 Mbps dalam radius maksimal 40-50 km pada bandwidth 20 MHz. Alokasi frekuensi yang dipakai Indonesia untuk jaringan WiMAX ini ialah 3,3 – 3,4 GHz. Penelitian ini dilakukan dengan melakukan proses pengukuran kinerja perangkat radio WiMAX yaitu HiMax 331-SS. Proses pengukuran dilakukan antara CPE dan base station dengan antenna sektoral 1200 pada ketinggian 45 m. Lokasi pengukuran dilakukan di beberapa area kota Bandung yang telah ditentukan sebelumnya. Hasil pengukuran memperlihatkan nilai CINR tertinggi adalah 31 dB dengan modulasi 64 QAM – ¾ dan terendah nilai 10 dB dengan modulasi BPSK 1/2. Nilai RSSI tertinggi -54 dBm berada dan nilai RSSI terendah -89 dBm. Nilai throughput tertinggi untuk layanan streaming video sebesar 1000,8 kbps (downlink) dengan modulasi 64 QAM – ¾. Nilai delay terendah sebesar 56,247 ms pada kondisi LOS dan tertinggi sebesar 139,5 ms pada kondisi NLOS. Nilai terbesar packet loss sebesar 20% yaitu pada lokasi pengukuran terjauh 14,3 km.Kata Kunci: delay, packet loss, RSSI, CINR, throughput, CPE, WiMAX . ABSTRACTWireless communication technologies have evolved more rapidly. WiMAX is a broadband technology that is supported by the IEEE standard 802.16-2004/d which is able to provide high speed data services of up to 75 Mbps within a radius of 40-50 km at a maximum bandwidth of 20 MHz. Indonesia frequency allocation used for the WiMAX network is 3.3 to 3.4 GHz. This study was conducted with the performance measurement process that is Himax 331 WiMAX radio - SS. Process measurement is made between the CPE and base station sector antennas at a height of 45 m in 1200. Locations measurements performed in several areas of Bandung predetermined. The measurement results show the highest CINR value is 31 dB with 64 QAM modulation - ¾ and the lowest value of 10 dB with BPSK modulation half. The highest RSSI value of -54 dBm being the lowest and -89 dBm RSSI value. The highest throughput for streaming video services by 1000.8 kbps ( downlink ) with 64 QAM modulation - ¾. The lowest value was 56.247 ms delay in LOS conditions and the highest was 139.5 ms in NLOS conditions. The greatest value by 20 % packet loss is the farthest measurement locations 14.3 km.Keywords: delay, packet loss, RSSI, CINR, throughput, CPE, WiMAX .

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Silva, Hugerles S., Marcelo S. Alencar, Wamberto J. L. Queiroz, Danilo B. T. Almeida e Francisco Madeiro. "Closed-Form Expression for the Bit Error Probability of the M-QAM for a Channel Subjected to Impulsive Noise and Nakagami Fading". Wireless Communications and Mobile Computing 2018 (21 ottobre 2018): 1–9. http://dx.doi.org/10.1155/2018/5934267.

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Abstract (sommario):

In this paper, new exact expressions for evaluating the bit error probability (BEP) of the M-ary quadrature amplitude modulation scheme (M-QAM) for a channel model characterized by double gated additive white Gaussian noise (G2AWGN) and Nakagami fading are presented. The derivation of the BEP is performed considering a method in which the multiplicative fading is transformed in an additive noise R obtained by dividing the received signal by the estimated fading envelope. In addition, the probability density function (PDF) and cumulative density function (CDF) of the random variable R that represents the aforementioned noise are obtained for the G2AWGN. The BEP curves as a function of the signal to permanent noise ratio for several values of the signal to impulsive noise ratio, modulation order, and fading parameters are also presented.

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Lao, Jonathan U. "Development of optimization model of the M-QAM and MPSK Modulation in AWGN channel". International Journal of Advanced Trends in Computer Science and Engineering 8, n. 3 (25 giugno 2019): 667–75. http://dx.doi.org/10.30534/ijatcse/2019/53832019.

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Yan, Xiao, Guoyu Zhang e Hsiao-Chun Wu. "A Novel Automatic Modulation Classifier Using Graph-Based Constellation Analysis for ${M}$ -ary QAM". IEEE Communications Letters 23, n. 2 (febbraio 2019): 298–301. http://dx.doi.org/10.1109/lcomm.2018.2889084.

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Ding, Ni, Parastoo Sadeghi e Rodney A. Kennedy. "On Monotonicity of the Optimal Transmission Policy in Cross-Layer Adaptive $m$ -QAM Modulation". IEEE Transactions on Communications 64, n. 9 (settembre 2016): 3771–85. http://dx.doi.org/10.1109/tcomm.2016.2590427.

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