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Letteratura scientifica selezionata sul tema "M-QAM MODULATION"

Autore: Grafiati

Pubblicato: 11 settembre 2023

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Articoli di riviste sul tema "M-QAM MODULATION"

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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Più fonti

Tesi sul tema "M-QAM MODULATION"

A, Sani Negar. "M-PSK and M-QAM Modulation/Demodulation of UWB Signal Using Six-Port Correlator". Thesis, Linköpings universitet, Fysik och elektroteknik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-64413.

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Nowadays high speed and high data rate communication are highly demanded. Consequently, wideband and high frequency transmitter and receivers should be designed. New transmitters and receivers should also have low power consumption, simple design and low manufacturing price in order to fulfill manufacturers’ requests for mass production. Having all above specifications, six-port correlator is a proper choice to be used as modulator and demodulator in transmitters and receivers. In this thesis the six-port correlator is introduced, modeled and simulated using Advanced Design System (ADS) software. A simple six-port transmitter/receiver system with a line of sight link is modeled and analyzed in BER, path length and noise terms. The modulation in this system is QAM, frequency is 7.5 GHz and symbol rate is 500 Msymbol/s. Furthermore two methods are proposed for high frequency and high symbol rate M-PSK and M-QAM modulation using six-port correlator. The 7.5 GHz modulators are modeled and simulated in ADS. Data streams generated by pseudo random bit generator with 1 GHz bandwidth are applied to modulators. Common source field effect transistors (FETs) with zero bias are used as controllable impedance termination to apply baseband data to modulator. Both modulators show good performance in M-PSK and M-QAM modulation.

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Fernandes, Diogo. "Low-cost implementation techniques for generic square and cross M-QAM constellations". Universidade Federal de Juiz de Fora, 2015. https://repositorio.ufjf.br/jspui/handle/ufjf/1555.

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CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico
Este trabalho tem como objetivo apresentar técnicas com complexidade computacional reduzida para implementação em hardware do modulador de amplitude em quadratura M-ária (M-ary quadrature amplitude modulation - M-QAM) de elevada ordem, que pode ser viável para sistemas banda larga. As técnicas propostas abrangem as constelações M-QAM quadradas e cruzadas (número par e ímpar de bits), a regra de decisão abrupta (hard decison rule), derivação de constelações M-QAM de baixa ordem das de elevada ordem. A análise de desempenho em termos de taxa de bits errados (bit error rate - BER) é realizada quando os símbolos M-QAM são corrompidos por ruído Gaussiano branco aditivo (additive white Gaussian noise - AWGN) e ruído Gaussiano impulsivo aditivo (additive impulsive Gaussian noise - AIGN). Os resultados de desempenho da taxa de bits errados mostram que a perda de desempenho das técnicas propostas é, em média, inferior a 1 dB, o que é um resultado surpreendente. Além disso, a implementação das técnicas propostas em arranjo de portas programÃ¡veis em campo (field programmable gate array - FPGA) é descrita e analisada. Os resultados obtidos com as implementações em dispositivo FPGA mostram que as técnicas propostas podem reduzir consideravelmente a utilização de recursos de hardware se comparadas com as técnicas presentes na literatura. Uma melhoria notável em termos de redução da utilização de recursos de hardware é conseguida através da utilização da técnica de modulação M-QAM genérica em comparação com a técnica de regra de decisão heurística (heuristic decision rule - HDR) aprimorada e uma técnica previamente concebida, a tÃ c cnica HDR. Com base nas análises apresentadas, a técnica HDR aprimorada é menos complexa do que a técnica HDR. Finalmente, os resultados numéricos mostram que a técnica de modulação M-QAM genérica pode ser oito vezes mais rápida do que as outras duas técnicas apresentadas, quando um grande número de símbolos M-QAM (p. ex., > 1000) são transmitidos consecutivamente.
This work aims at introducing techniques with reduced computational complexity for hardware implementation of high order M-ary quadrature amplitude modulation (MQAM) which may be feasible for broadband communication systems. The proposed techniques cover both square and cross M-QAM constellations (even and odd number of bits), hard decision rule, derivation of low-order M-QAM constellations from high order ones. Performance analyses, in terms of bit error rate (BER) is carried out when the M-QAM symbols are corrupted by either additive white Gaussian noise (AWGN) or additive impulsive Gaussian noise (AIGN). The bit error rate performance results show that the performance loss of the proposed techniques is, on average, less than 1 dB, which is a remarkable result. Additionally, the implementation of the proposed techniques in field programmable gate array (FPGA) device is described and outlined. The results based on FPGA show that the proposed techniques can considerably reduce hardware resource utilization. A remarkable improvement in terms of hardware resource utilization reduction is achieved by using the generic M-QAM technique in comparison with the enhanced heuristic decision rule (HDR) technique and a previously designed technique, the HDR technique. Based on the analyses performed, the enhanced HDR technique is less complex than the HDR technique. Finally, the numerical results show that the generic M-QAM technique can be eight times faster than the other two techniques when a large number of M-QAM symbols (e.g., > 1000) are consecutively transmitted.

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Ceballos, Emmanuel Gonzales. "A Novel Adaptive Multilevel - Quadrature Amplitude Modulation (M-QAM) Receiver Using Machine Learning to Mitigate Multipath Fading Channel Effects". Thesis, California State University, Long Beach, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10784157.

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The demand for faster speed and greater signal strength of today’s wireless broadband technology evolved signaling techniques to improve spectral bandwidth efficiency. In wireless digital communications, higher-order of M-QAM technique has been employed to improve bandwidth and channel efficiency of the signaling. However, wireless broadband communications such as mobile phones and wireless access networks are prone to multipath fading channel. Higher-order M-QAM is very susceptible to this fading channel because it affects both the amplitude and carrier phase of the transmitted signal as it induces non-linearity.

In this study, an innovative approach in M-QAM demodulation technique has been proposed. This thesis investigated the performance of a proposed modified Costas Loop M-QAM receiver that employed Machine Learning using multi-layer perceptron (MLP) with error-back propagation (EBP) as an adaptive amplitude fading estimator and, using fuzzy logic as loop filter in the phase lock loop (PLL) circuit that estimated the distorted carrier phase of a received signal. A computer simulation of the proposed receiver was developed to investigate the performance of the receiver’s signal recovery over Rayleigh fading channel. The results showed that the ML algorithm tracked well the phase noise and the bit-error rate (BER) were comparable to the theoretical M-QAM curve on certain values of signal-to-noise (SNR) levels.

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Abdurrhman, Ahmed B. M. "Error resilient video communications using high level M-QAM : modelling and simulation of a comparative analysis of a dual-priority M-QAM transmission system for H.264/AVC video applications over band-limited and error-phone channels". Thesis, University of Bradford, 2010. http://hdl.handle.net/10454/4913.

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An experimental investigation of an M level (M = 16, 64 and 256) Quadrature Amplitude Modulation (QAM) transmission system suitable for video transmission is presented. The communication system is based on layered video coding and unequal error protection to make the video bitstream robust to channel errors. An implementation is described in which H.264 video is protected unequally by partitioning the compressed data into two layers of different visual importance. The partition scheme is based on a separation of the group of pictures (GoP) in the intra-coded frame (I-frame) and predictive coded frame (P frame). This partition scheme is then applied to split the H.264-coded video bitstream and is suitable for Constant Bit Rate (CBR) transmission. Unequal error protection is based on uniform and non-uniform M-QAM constellations in conjunction with different scenarios of splitting the transmitted symbol for protection of the more important information of the video data; different constellation arrangements are proposed and evaluated to increase the capacity of the high priority layer. The performance of the transmission system is evaluated under Additive White Gaussian Noise (AWGN) and Rayleigh fading conditions. Simulation results showed that in noisy channels the decoded video can be improved by assigning a larger portion of the video data to the enhancement layer in conjunction with non-uniform constellation arrangements; in better channel conditions the quality of the received video can be improved by assigning more bits in the high priority channel and using uniform constellations. The aforementioned varying conditions can make the video transmission more successful over error-prone channels. Further techniques were developed to combat various channel impairments by considering channel coding methods suitable for layered video coding applications. It is shown that a combination of non-uniform M-QAM and forward error correction (FEC) will yield a better performance. Additionally, antenna diversity techniques are examined and introduced to the transmission system that can offer a significant improvement in the quality of service of mobile video communication systems in environments that can be modelled by a Rayleigh fading channel.

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Abdurrhman, Ahmed B. M. "Error relilient video communications using high level M-QAM. Modelling and simulation of a comparative analysis of a dual-priority M-QAM transmission system for H.264/AVC video applications over band-limited and error-phone channels". Thesis, University of Bradford, 2010. http://hdl.handle.net/10454/4913.

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Forestier, Stéphane. "Gestion dynamique de la génération de puissance en hyperfréquence pour des modulations numériques : Applications à l'optimisation des performances d'un amplificateur millimétrique". Limoges, 2003. http://aurore.unilim.fr/theses/nxfile/default/0550ccba-ec85-4e00-a664-f090f687c9d2/blobholder:0/2003LIMO0019.pdf.

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Les travaux présentés dans ce mémoire concernent dans un premier temps, l'étude des phénomènes de distorsion engendrés par la partie amplificatrice lors de l 'émission d'un signal. La recherche menée permet de modéliser et de caractériser ces phénomènes non-linéaires dans le cas d'un transistor P-PHEMT. L'analyse, validée par des mesures en puissance de type 'Load-Pull' aux fréquences millimétriques, montre la dépendance de la linéarité en termes de conversion de phase par rapport aux impédances de fermeture aux accès et aux éléments non-linéaires intrinsèques du transistor (capacités CGS et CDS, transconductance GM). Il est démontré que pour certaines conditions de fonctionnement, des phénomènes internes de compensations entre non-linéarités existent et peuvent être exploités pour améliorer la linéarité de l'amplificateur. L'étude proposée a mis également en évidence la nécessité de rechercher un compromis 'pertes d'adaptation en entrée' / linéarité. Le deuxième objectif que vise ce travail est de mettre en œuvre une méthode permettant d'obtenir de manière optimale l'ensemble des performances en puissance de l'amplificateur SSPAs : puissance de sortie, consommation et linéarité, en vue de l'utilisation d'une modulation numérique M-QAM pour des applications spatiales. La méthode proposée consiste en une gestion dynamique du comportement de l'amplificateur par le biais de sa polarisation. Pour démontrer l'intérêt de cette méthode, un amplificateur de puissance hybride à un étage a été conçu avec un transistor en technologie Power PHEMT à 19. 8 GHz. Un système de détection d'enveloppe et de commande de polarisation en grille et en drain d'amplificateur a aussi été développé. Différentes comparaisons expérimentales sur les performances avec ou sans le système de commande de la polarisation de l'amplificateur ont validé l'intérêt de la méthode développée pour une modulation de type 16QAM

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JHA, MOHIT. "DESIGN OF WIRELESS COMMUNICATION SYSTEM ON SDR USING M-QAM MODULATION". Thesis, 2018. http://dspace.dtu.ac.in:8080/jspui/handle/repository/16530.

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Basic idea of this project is to design a communication channel using software defined radio.The main purpose of Software Defined Radio was to design a device which should be competent of working with many radios working at different parameters. Software Defined Radio provide an rational and economical solution for building multi-mode, multi-range and multifunctional wireless devices that can be revamped by means of software furtherance. In a PC significant signal processing can be done via SDR. In SDR, signal worked in digital sphere rather in analog sphere as in the orthodox radio. The analog signal can be changed to the digital domain with the aid of Analog to Digital converter. In the digital QAM, a fixed number of two phases and minimum two amplitudes are used. PSK modulation scheme are often made with the QAM theory, but are not deemed as QAM as the amplitude of the modulated carrier signal is same. We are using the QAM because of the issue that a amplitude modulated signal, i.e. double sideband with a suppressed carrier occupies two times the bandwidth of the modulating signal. Assumingly large spectral efficiencies can be get with QAM by adjusting a acceptable constellation range, fixed only by the noise stages and linearity of the communications channel. Quadrature amplitude modulation (QAM) is combination of analog and a digital modulation system. It fetchs two analog message signals, or two digital bit streams, by amending (modulating) the amplitudes of two carrier waves, using the amplitude-shift keying (ASK) digital modulation scheme or amplitude modulation (AM) analog modulation system. The carrier signals of the like frequencies, mostly sinusoids, are out of phase with one other by 90° and are called quadrature carriers or quadrature parts — so the name of the system. The modulated waves are added, and the end waveform is a merger of both phase-shift keying (PSK) and amplitude-shift keying (ASK), or, in the analog system, of phase modulation (PM) and amplitude modulation.

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Capitoli di libri sul tema "M-QAM MODULATION"

Lee, Sang-Do, e Young-Chai Ko. "Hybrid M-QAM with Adaptive Modulation and Selection Combining in MIMO Systems". In Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering, 91–100. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-11284-3_10.

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Chandra, A., e C. Bose. "Error Probability for Coherent Modulations in Rician Fading Channel". In Networking and Telecommunications, 1741–52. IGI Global, 2010. http://dx.doi.org/10.4018/978-1-60566-986-1.ch112.

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Simple closed-form solutions for the average error rate of several coherent modulation schemes including square M-QAM, DBPSK and QPSK operating over slow flat Rician fading channel are derived. Starting from a novel unified expression of conditional error probability the error rates are analysed using PDF based approach. The derived end expressions composed of infinite series summations of Gauss hypergeometric function are accurate, free from any numerical integration and general enough, as it encompasses as special situations, some cases of non-diversity and Rayleigh fading. Error probabilities are graphically displayed for the modulation schemes for different values of the Rician parameter K. In addition, to examine the dependence of error rate performance of M-QAM on the constellation size, numerical results are plotted for various values of M. The generality of the analytical results presented offers valuable insight into the performance evaluation over a fading channel in a unified manner.

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Li, Huiqiong, Ying Wei e Changjian Zhu. "Convolutional Neural Network Analysis for Modulation Classification of Wireless Communication Signal". In Advances in Transdisciplinary Engineering. IOS Press, 2022. http://dx.doi.org/10.3233/atde221103.

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Modulation classification detects the modulation type of received signals to guarantee that the signals can be correctly demodulated and that the transmitted message can be accurately recovered. For the modulation classification of M-PSK, M-QAM and M-APSK modulated signals with similar constellation maps, we analyze waveform characteristics of the signal in the time domain. Based on the waveform characteristics of the signal, we explore the feasibility of using convolutional neural network (CNN) to identify the modulation classification of the signal. We analyze the data input structure and network model required for modulation classification using CNN. Considering the impairment of the signal by additive white Gaussian noise (AWGN), clock offset and Rician multipath fading, a combined channel is simulated in this paper to obtain the impaired data as dataset. The simulation results show that CNN has great potential for modulation classification.

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You, Cheolwoo, e Daesik Hong. "Learning Algorithms for Complex-Valued Neural Networks in Communication Signal Processing and Adaptive Equalization as its Application". In Complex-Valued Neural Networks, 194–235. IGI Global, 2009. http://dx.doi.org/10.4018/978-1-60566-214-5.ch009.

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In this chapter, the complex Backpropagation (BP) algorithm for the complex backpropagation neural networks (BPN) consisting of the suitable node activation functions having multi-saturated output regions is presented and analyzed by the benchmark testing. And then the complex BPN is utilized as nonlinear adaptive equalizers that can deal with both quadrature amplitude modulation (QAM) and phase shift key (PSK) signals of any constellation sizes. In addition, four nonlinear blind equalization schemes using complex BPN for M-ary QAM signals are described and their learning algorithms are presented. The presented complex BP equalizer (CBPE) gives, compared with conventional linear complex equalizers, an outstanding improvement with respect to bit error rate (BER) when channel distortions are nonlinear.

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Gupta, Yogendra, e Sandeep Saini. "Thermometer to Gray Encoders". In Advances in Computer and Electrical Engineering, 323–35. IGI Global, 2015. http://dx.doi.org/10.4018/978-1-4666-6627-6.ch013.

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Analog to Digital Converter (ADC) is a key functional block in the design of mixed signal, system on chip, and signal processing applications. An optimized method for the direct conversion of analog signal to Gray code representation is presented. This eliminates the need for binary-to-Gray code conversion in many digital modulation techniques like M-PSK and M-QAM, which uses Gray coding representation to represent the symbols that are modulated. The authors design a low-power and high-speed Thermometer to Gray encoder for Flash ADC, as encoders have been widely utilized in high-performance critical applications which persistently impose special design constraints in terms of high-frequency, low power consumption, and minimal area. In this chapter, they propose a new circuit that converts the Thermometer code to Gray code and also yields minimized power.

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Abualhaol, Ibrahim Y., e Mustafa M. Matalgah. "Resource Allocation for a Cooperative Broadband MIMO-OFDM System". In Cooperative Communications for Improved Wireless Network Transmission, 382–98. IGI Global, 2010. http://dx.doi.org/10.4018/978-1-60566-665-5.ch014.

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In this chapter, a cooperative broadband relay-based resource allocation technique is proposed for adaptive bit and power loading multiple-input-multiple-output/orthogonal frequency division multiplexing (MIMO-OFDM) system. In this technique, sub-channels allocation, M-QAM modulation order, and power distribution among different sub-channels in the relay-based MIMO-OFDM system are jointly optimized according to the channel state information (CSI) of the relay and the direct link. The transmitted stream of bits is divided into two parts according to a suggested cooperative protocol that is based on sub-channel-division. In this protocol, the first part is sent directly from the source to the destination, and the second part is relayed to the destination through an indirect link. Such a cooperative relay-based system enables us to exploit the inherent system diversities in frequency, space and time to maximize the system power efficiency. The BER performance using this cooperative sub-channel-division protocol with adaptive sub-channel assignment and adaptive bit/power loading are presented and compared with a noncooperative ones. The use of cooperation in a broadband relay-based MIMO-OFDM system showed high performance improvement in terms of BER.

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Atti di convegni sul tema "M-QAM MODULATION"

Jia, Haowei, e Leila Musavian. "Performance Analysis for NOMA with M-QAM Modulation". In 2020 IEEE 91st Vehicular Technology Conference (VTC2020-Spring). IEEE, 2020. http://dx.doi.org/10.1109/vtc2020-spring48590.2020.9129150.

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Gomes, Marco, Francisco Cercas, Vitor Silva e Martin Tomlinson. "Efficient M-QAM Transmission Using Compacted Magnitude Modulation Tables". In IEEE GLOBECOM 2008 - 2008 IEEE Global Telecommunications Conference. IEEE, 2008. http://dx.doi.org/10.1109/glocom.2008.ecp.895.

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Zhendong, Chou, Jiang Weining, Xiang Changbo e Li Min. "Modulation recognition based on constellation diagram for M-QAM signals". In 2013 IEEE 11th International Conference on Electronic Measurement & Instruments (ICEMI). IEEE, 2013. http://dx.doi.org/10.1109/icemi.2013.6743041.

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Kalantari, Ashkan, Christos Tsinos, Mojtaba Soltanalian, Symeon Chatzinotas, Wing-Kin Ma e Bjorn Ottersten. "MIMO directional modulation M-QAM precoding for transceivers performance enhancement". In 2017 IEEE 18th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC). IEEE, 2017. http://dx.doi.org/10.1109/spawc.2017.8227801.

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Gaire, Sunil Kumar, e Saleh Faruque. "Performance analysis of orthogonal coded M-ary QAM modulation technique". In 2017 51st Annual Conference on Information Sciences and Systems (CISS). IEEE, 2017. http://dx.doi.org/10.1109/ciss.2017.7926152.

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Queiroz, Wamberto J. L., Waslon T. A. Lopes, Francisco Madeiro e Marcelo S. Alencar. "Bit error probability of M-QAM and I × J-QAM modulation schemes in Nakagami fading". In International Microwave and Optoelectronics Confererence. IEEE, 2007. http://dx.doi.org/10.1109/imoc.2007.4404381.

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Wang, Shiqiang, Qingyang Song, Lei Guo e Abbas Jamalipour. "Constellation mapping for physical-layer network coding with M-QAM modulation". In GLOBECOM 2012 - 2012 IEEE Global Communications Conference. IEEE, 2012. http://dx.doi.org/10.1109/glocom.2012.6503815.

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Sadinov, S. M. "Simulation study of M-ARY QAM modulation techniques using Matlab/Simulink". In 2017 40th International Convention on Information and Communication Technology, Electronics and Microelectronics (MIPRO). IEEE, 2017. http://dx.doi.org/10.23919/mipro.2017.7973486.

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Yan, Xiao, Guoyu Zhang, Jie Luo, Hsiao-Chun Wu, Qian Wang e Yiyan Wu. "Graph-based Automatic Modulation Classifier for M-ary Generalized QAM Signals". In 2019 3rd International Conference on Imaging, Signal Processing and Communication (ICISPC). IEEE, 2019. http://dx.doi.org/10.1109/icispc.2019.8935869.

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Cai, Tian, Cheng Wang, Gaofeng Cui e Weidong Wang. "Constellation-wavelet transform automatic modulation identifier for M-ary QAM signals". In 2015 IEEE 26th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC). IEEE, 2015. http://dx.doi.org/10.1109/pimrc.2015.7343297.

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