Articoli di riviste sul tema "High symbol rate transmissions"
Segui questo link per vedere altri tipi di pubblicazioni sul tema: High symbol rate transmissions.
Cita una fonte nei formati APA, MLA, Chicago, Harvard e in molti altri stili
Vedi i top-50 articoli di riviste per l'attività di ricerca sul tema "High symbol rate transmissions".
Accanto a ogni fonte nell'elenco di riferimenti c'è un pulsante "Aggiungi alla bibliografia". Premilo e genereremo automaticamente la citazione bibliografica dell'opera scelta nello stile citazionale di cui hai bisogno: APA, MLA, Harvard, Chicago, Vancouver ecc.
Puoi anche scaricare il testo completo della pubblicazione scientifica nel formato .pdf e leggere online l'abstract (il sommario) dell'opera se è presente nei metadati.
Vedi gli articoli di riviste di molte aree scientifiche e compila una bibliografia corretta.
1
Abboud, Maryam K., e Bayan M. Sabbar. "Performance evaluation of high mobility OFDM channel estimation techniques". International Journal of Electrical and Computer Engineering (IJECE) 10, n. 3 (1 giugno 2020): 2562. http://dx.doi.org/10.11591/ijece.v10i3.pp2562-2568.
Abstract (sommario):
In wireless communication, Orthogonal Frequency Division Multiplexing (OFDM) has been adopted due to its robustness to multipath fading and high data rate transmissions. At the other hand, the performance of OFDM systems severely degraded due to multi-path fading and Doppler frequency shifts in mobile systems, which causes inter-carrier-interference (ICI). Thus, Estimation of channel parameters is required at the receiver using a pre designed estimator where pilot tones are inserted in each OFDM symbol. In this paper, a random pilot data are generated and inserted in each OFDM symbol at equally spaced locations. The performance test of Least Square (LS) and Linear Minimum Mean Square (LMMSE) estimation methods are proposed with Discrete Fourier Transform (DFT) based on both LS and LMMSE, where different ITU channel models are considered in order to compare their performance for data transmission in high mobile systems with different Doppler frequencies exceeds 200 Hz and minimal number of pilots.
2
Sharma, Mahendra, e Santhosh Kumar Singh. "Orthogonality Measurent of OFDM Signal". Indonesian Journal of Electrical Engineering and Computer Science 9, n. 3 (1 marzo 2018): 595. http://dx.doi.org/10.11591/ijeecs.v9.i3.pp595-598.
Abstract (sommario):
<p>In recent days, Orthogonal Frequency Division Multiplexing is the technique to transmit and receive the signal without any overlapping of the signal. OFDM is also a multiplexing technique as well as modulation technique. It is a multi-carrier transmission technique in which single high data stream is divided into a number of lower rate streams that are transmitted simultaneous over some narrow sub channel. In general, OFDM avoids Inter-Symbol Interference (ISI), Inter-Carrier Interference (ICI) and fault transmissions between source and destination node. To measure the performance of the system by using the parameters like Bit Error rate (BER), Spectrum analysis and signal strength detection. Based on the parameters the best system can be identified.</p>
3
Raybon, Gregory, Andrew Adamiecki, Peter J. Winzer, Sebastian Randel, Luis Salamanca, A. Konczykowska, Filip Jorge et al. "High Symbol Rate Coherent Optical Transmission Systems: 80 and 107 Gbaud". Journal of Lightwave Technology 32, n. 4 (febbraio 2014): 824–31. http://dx.doi.org/10.1109/jlt.2013.2286963.
4
Rajaram, Akashkumar, Rui Dinis, Dushnatha Nalin K. Jayakody e Marko Beko. "Secure Information Transmission with Self Jamming SWIPT". Electronics 9, n. 4 (30 marzo 2020): 587. http://dx.doi.org/10.3390/electronics9040587.
Abstract (sommario):
This article is focused on implementing simultaneous wireless information and power transmission as a physical layer security measure by using artificial noise. A series of high energy precoded symbols is simultaneously transmitted along with the information symbols over a Rayleigh frequency selective fading channel. The high energy precoded symbols act as an artificial noise for the eavesdroppers. The energy symbols are precoded on the basis of a legitimate user’s channel matrix to form a null space vector, which eliminates the interference of energy symbols at the information symbol receiver antennas, while allowing the rectenna to harvest energy from the superimposed information and energy symbols. We analyze the secrecy rate and error rate performance at the receiver under different circumstances, and we show that the performance of the legitimate user can be improved by using the iterative block decision feedback equalization method at the receiver.
5
García-Pérez, A., J. A. Andrade-Lucio, O. G. Ibarra-Manzano, E. Alvarado-Méndez, M. Trejo-Duran e H. Gutiérrez-Martín. "Efficient Modulation Formats for High Bit-Rate Fiber Transmission". Acta Universitaria 16, n. 2 (1 agosto 2006): 17–26. http://dx.doi.org/10.15174/au.2006.184.
Abstract (sommario):
The topic of this report will deal with the study of advanced modulation formats for highspeed optical communication systems. Basically, the use of alternate polarization modulation (alP) is considered in order to reduce the inter-symbol interference (ISI) caused mainly by effects such as Chromatic Dispersion (CD), Polarization Mode Dispersion (PMD) and Nonlinear effects. The comparative analysis among the different formats is carried out by means of the obtaining of its different spectrums. A detailed analysis of these and their dependency to the modulation format that generates it is presented. The article presents numerical comparative analysis using commercial software VPI Maker Transmission, where the results obtained show that the formats of alternating polarization are the best results at the bit rate of 40 Gb/s per channel.
6
Nagatani, M., H. Wakita, H. Nosaka, K. Kurishima, M. Ida, A. Sano e Y. Miyamoto. "75 GBd InP‐HBT MUX‐DAC module for high‐symbol‐rate optical transmission". Electronics Letters 51, n. 9 (aprile 2015): 710–12. http://dx.doi.org/10.1049/el.2015.0686.
7
Huu Ai, Duong, Dai Tho Dang, Cong Dat Vuong, Van Loi Nguyen e Khanh Ty Luong. "Average symbol error rate analysis of reconfigurable intelligent surfaces based free-space optical link over Weibull distribution channels". International Journal of Electrical and Computer Engineering (IJECE) 14, n. 1 (1 febbraio 2024): 443. http://dx.doi.org/10.11591/ijece.v14i1.pp443-450.
Abstract (sommario):
Optical wireless communication (OWC) enables wireless connectivity using ultraviolet bands, infrared or visible. With its advantages features as high bandwidth, low cost, and operation in an unregulated spectrum. Free-space optical (FSO) communication systems are near terrestrial as a communication link between transceivers, the link is line-of-sight and successfully transmitted optical signals. Nevertheless, the optical signals transmissions over the FSO channels bring challenges to the system. To overcome the challenges posed by the FSO channels, the most common technique is to use relay stations, the most recent is the reconfigurable intelligent surfaces (RISs) technique. This study introduces a Weibull distribution model for a free-space optical communication link with RISs assisted, the parameter used to evaluate the performance of the system is the average symbol error rate (ASER). The RISs effect is examined by considering the influence of the transmitter beam waist radius, shape parameter, aperture radius, scale parameter, and signal-to-noise ratio on the ASER.
8
Fan, Wei Wei, Bo Li, You Wen Zhang e Da Jun Sun. "Research of FH-MFSK Underwater Acoustic Communication Based on Non-Binary LDPC Codes". Applied Mechanics and Materials 519-520 (febbraio 2014): 945–52. http://dx.doi.org/10.4028/www.scientific.net/amm.519-520.945.
Abstract (sommario):
Compared with binary-modulation, Multiple-modulation can obtain higher rate of transmission in the condition of same symbol-rate. If using binary channel codes with multiple-modulation, there exists an problem of information-loss of the probability from bit to symbol conversion. Underwater acoustic channel is an multipath, time-variation, high-noise and strong doppler-effect wireless channel, which leads to high error-rate caused by signal distortion. To solve the problems above, we adopt FH-MFSK modulation to overcome the inter-symbol interference by multipath. The PN sequence is used as a frame synchronization signal and frequency energy accumulation method is used to detect the frame-synchronization. PN hopping signal is chosen to estimate the doppler frequency-shift and using non-binary LDPC codes based on symbol for channel error codes. Finally, We perform numerical simulations and the experiments on the lake to show that compared with binary LDPC codes, non-binary LDPC codes for multiple-modulation can achieve same error-rate under lower SNR.
9
Ling, Peng, Maolin Li e Weipeng Guan. "Channel-Attention-Enhanced LSTM Neural Network Decoder and Equalizer for RSE-Based Optical Camera Communications". Electronics 11, n. 8 (17 aprile 2022): 1272. http://dx.doi.org/10.3390/electronics11081272.
Abstract (sommario):
In an RGB-LED-based optical camera communication system, it is an essential goal to have better performance in the data rate and BER. However, in a higher symbol rate, due to the conventional sampling algorithm, the deterioration of transmission performance brought by the inter-symbol interference and inter-channel interference is significant. Innovatively, in this paper, the sub-image obtained by a captured frame of received video is encoded by a channel-attention-Net-based encoder to generate a descriptor without existing sampling methods. Moreover, we propose an LSTM-based equalizer to decode the descriptor and mitigate transmission performance deterioration. Utilizing the long-short-term memory of an LSTM unit, an equalizer not only can reduce bit error rates but also increase the data rate. The experimental results show that at a symbol rate of 46 kbaud/s, a record-high data rate at 44.03 kbit/s is achieved under random data transmission while still meeting the pre-forward error correction requirement.
10
Zhang, Junwen, e Jianjun Yu. "Generation and Transmission of High Symbol Rate Single Carrier Electronically Time-Division Multiplexing Signals". IEEE Photonics Journal 8, n. 2 (aprile 2016): 1–6. http://dx.doi.org/10.1109/jphot.2016.2530565.
11
Jiang, Dong Chu, Yu Shan Li e Yong Zhe Qu. "Precise Driver-Side Equalization of Capacitive Coupling Connector". Applied Mechanics and Materials 380-384 (agosto 2013): 3396–99. http://dx.doi.org/10.4028/www.scientific.net/amm.380-384.3396.
Abstract (sommario):
Capacitive coupling connector subjects to excessive inter-symbol interference with the increasing of signal transmission rate. To solve this problem, a driver-side equalization scheme is proposed, and the calculation method of precise equalization ratio for this scheme is also given. The equalization scheme is implemented through select appropriate equalization ratio to increase high frequency components of signal and reduce the low frequency components of signal at the driver-side at the drive-side. It can reduce the inter-symbol interference and improve pulse magnitude effectively. Simulation and calculation results show that the equalization scheme can increase the pulse amplitude in receiver-side, eliminate inter-symbol interference and improve signal transmission rate greatly.
12
Zacko Gbadoubissa, Jocelyn Edinio, Ado Adamou Abba Ari, Emanuel Radoi e Abdelhak Mourad Gueroui. "M-Ary Direct Modulation Chirp Spread Spectrum for Spectrally Efficient Communications". Information 14, n. 6 (6 giugno 2023): 323. http://dx.doi.org/10.3390/info14060323.
Abstract (sommario):
Spread spectrum techniques, such as the Chirp Spread Spectrum (CSS) used by LoRa technology, are important for machine-to-machine communication in the context of the Internet of Things. They offer high processing gain, reliable communication over long ranges, robustness to interference and noise in harsh environments, etc. However, these features are compromised by their poor spectral efficiency, resulting in a very low data transmission rate. This paper deals with a spectrally efficient variant of CSS. The system uses M-ary phase keying to modulate the data and exploits CSS’s properties to transmit the modulated symbols as overlapping chirps. The overlapping of chirp signals may affect the system performance due to inter-symbol interference. Therefore, we analyse the relationship between the number of overlaps and the effect of inter-symbol interference (ISI), and we also determine the BER expression as a function of the number of overlaps. Finally, we derive the optimal number of overlapping symbols that corresponds to the minimum error probability.
13
Ue, T., S. Sampei, N. Morinaga e K. Hamaguchi. "Symbol rate and modulation level-controlled adaptive modulation/TDMA/TDD system for high-bit-rate wireless data transmission". IEEE Transactions on Vehicular Technology 47, n. 4 (1998): 1134–47. http://dx.doi.org/10.1109/25.728485.
14
Deng, Xianzheng, Xin Bian e Mingqi Li. "LDM-Ex-FDM: A Novel Multi-Service Transmission Scheme for the ATSC 3.0 System". Applied Sciences 11, n. 7 (2 aprile 2021): 3178. http://dx.doi.org/10.3390/app11073178.
Abstract (sommario):
In order to improve system coverage performance, in this paper, a multi-service transmission scheme on the basis of the puncturing technique, namely layered division multiplexing extension frequency-division multiplexing (LDM-Ex-FDM), is proposed. The key idea of the proposed scheme is that the symbols punctured from the enhanced layer (EL) of fixed services will be independently transmitted on a certain number of subcarriers orthogonal to the LDM signal of the core layer (CL) and most of the EL. By doing so, the punctured symbols will be demodulated with a higher signal-to-noise ratio (SNR) on the receiver side and can be recovered well, thus improving the reception performance of the EL fixed services. Moreover, two puncturing strategies based on bit-interleaved coded modulation (BICM) symbols of the LDM-Ex-FDM scheme, namely equal interval symbol puncturing (EISP) and non-equal interval symbol puncturing (NEISP), are developed to improve the performance of the EL services. Simulation results are given to show that, when the puncturing rate in the LDM-Ex-FDM scheme is configured as 1/12, the performance of the fixed service can be improved by 1.8 dB, meanwhile the bit error rate (BER) performance of the mobile service is not affected. Thus, the overall system coverage performance can be improved. Furthermore, to reduce the computational complexity and the demodulation delay of fixed service carried in the EL, at the receiver, a direct interference cancellation (DIC) detector is proposed as well. Simulation results are given to show that, under high injection level and high modulation order, the proposed DIC scheme is able to achieve almost the same BER performance as that of the traditional successive interference cancellation (SIC) scheme while with lower computational complexity.
15
Ue, T., S. Sampei e N. Morinaga. "Symbol rate and modulation level controlled adaptive modulation system with TDMA/TDD for high bit rate transmission in high delay spread environments". Electronics Letters 32, n. 4 (1996): 304. http://dx.doi.org/10.1049/el:19960223.
16
Bandari, Shravan Kumar, V. V. Mani e A. Drosopoulos. "Performance analysis of GFDM in various fading channels". COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering 35, n. 1 (4 gennaio 2016): 225–44. http://dx.doi.org/10.1108/compel-06-2015-0215.
Abstract (sommario):
Purpose – The purpose of this paper is to study the performance of generalized frequency division multiplexing (GFDM) in some frequency selective fading channels. The exact symbol error rate (SER) expressions in Hoyt (Nakagami-q) and Weibull-v fading channels are derived. A GFDM transceiver simulation test bed is provided to validate the obtained analytical expressions. Design/methodology/approach – Modern cellular system demands higher data rates, very low-latency transmissions and sensors with ultra low-power consumption. Current cellular systems of the fourth generation (4G) are not able to meet these emerging demands of future mobile communication systems. To address this requirement, GFDM, a novel multi-carrier modulation technique is proposed to satisfy the future needs of fifth generation technology. GFDM is a block-based transmission method where pulse shaping is applied circularly to individual subcarriers. Unlike traditional orthogonal frequency division multiplexing, GFDM transmits multiple symbols per subcarrier. The authors have used the probability density function approach in solving the final analytical expressions. Findings – Detailed analysis of GFDM performance under Hoyt-q, Weibull-v and Log-Normal Shadowing fading channels. Exact analytical formulae were derived which support the simulations carried out by authors and other authors. The exact dependence of SER on fading parameters and roll-off factor α in the raised cosine pulse shape filter was determined. Practical implications – Development and fabrication of high-performance GFDM systems under fading channel conditions. Originality/value – Theoretical support to simulated system performance.
17
Wang, Fei, Zhiqun Cheng, Hang Li e Dan Zhu. "A Software and Hardware Cooperation Method for Full Nyquist Rate Transmission Symbol Synchronization at E-Band Wireless Communication". Sensors 22, n. 22 (18 novembre 2022): 8924. http://dx.doi.org/10.3390/s22228924.
Abstract (sommario):
Compared with the conventional pulse-shaping transmission system, the full Nyquist rate transmission system with large bandwidth is sensitive to the sampling phase. It has only one sample available in one symbol period and is easily interfered by the channel, which does not allow the traditional symbol synchronization methods to be used directly. Another challenge is that the resource utilization for sampling data processing needs to be minimized due to the excessive consumption of the high data throughput in hardware resources. To solve these issues, we propose a symbol synchronization method based on the combination of software and hardware, which mainly includes two processes: Obtaining the initial phase by using Chirp signal and MOE criterion before communication; tracking the real-time phase using an on-line gradient table and frequency domain analysis of known data during communication. Both processes are proceeded with a phase adjustable clock. Through hardware verification, the sampling phase can be kept close to the optimal phase, thus ensuring the accuracy of the sampling data, and improving the system BER performance.
18
Lei, Zhang, Cong Feng Liu, Wei Jiang, Gui Zhou Xu e Ning Dai. "Performance Analysis of OFDM Channel System". Advanced Materials Research 268-270 (luglio 2011): 1438–46. http://dx.doi.org/10.4028/www.scientific.net/amr.268-270.1438.
Abstract (sommario):
OFDM is a promising digital communications technique for high data rate transmissions. In this paper, we have analyzed the performance of mobile OFDM systems in the presence of channel estimation error. A new channel estimation error model is presented. Based on the estimation error model, new and simple expressions for the average bit error probability of M-QAM OFDM systems are derived for zero-forcing, minimum mean square error and maximum likelihood receivers. A complex correlation coefficient is used to quantify the quality of the channel estimation scheme. We have shown that if the complex correlation coefficient is a function of the signal to noise ratio, then the inter-carrier interference caused by channel variations is the dominant source of performance degradation. On the other hand, if the channel estimation scheme produces a constant value for the complex correlation coefficient (estimation quality is not a function of the signal to noise ratio), then the channel estimation error will cause an error floor that is larger than the one caused by the inter-carrier interference, and is considered as one of the dominant causes of degradation. And channel estimation using pilot symbols are discussed in terms of different pilot symbol placement schemes.
19
Zhuo, Xinran, Jianxiong Pan, Huwei Wang, Xiangming Li e Neng Ye. "Enhancing PAPR and Throughput for DFT-s-OFDM System Using FTN and IOTA Filtering". Sensors 22, n. 13 (29 giugno 2022): 4907. http://dx.doi.org/10.3390/s22134907.
Abstract (sommario):
High frequency wireless communication aims to provide ultra high-speed transmissions for various application scenarios. The waveform design for high frequency communication is challenging due to the requirements for high spectrum efficiency, as well as good hardware compatibility. With high flexibility and low peak-to-average power ratio (PAPR), discrete Fourier transformation spreading-based orthogonal frequency division multiplexing (DFT-s-OFDM) can be a promising candidate waveform. To further enhance the spectral efficiency, we integrate faster-than-Nyquist (FTN) signaling in DFT-s-OFDM, and find that the PAPR performance can also be improved. While FTN can introduce increased inter-symbol interference (ISI), in this paper, we deploy an isotropic orthogonal transform algorithm (IOTA) filter for FTN-enhanced DFT-s-OFDM, where the compact time-frequency structure of the IOTA filter can significantly reduce the ISI. Simulation results show that the proposed waveform is capable of achieving good performance in PAPR, bit error rate (BER) and throughput, simultaneously, with 3.5 dB gain in PAPR and 50% gain in throughput.
20
Qin, Dong, e Tianqing Zhou. "Symbol Error Probability Optimization of OFDM Bidirectional AF Relaying Systems". Journal of Advanced Computational Intelligence and Intelligent Informatics 27, n. 1 (20 gennaio 2023): 96–100. http://dx.doi.org/10.20965/jaciii.2023.p0096.
Abstract (sommario):
This paper considers that two transceivers exchange orthogonal frequency division multiplexing (OFDM) signals with the aid of multiple bidirectional amplify and forward (AF) relays. Unlike most researchers who care about sum rate maximization issues to improve transmission efficiency, we formulate a symbol error probability (SEP) minimization problem under total power constraint because high data rate may degrade SEP performance. A joint algorithm of power allocation and relay selection is proposed to study their impact on the SEP performance. The closed-form solution of power allocation is not a form of water filling widely used in the sum rate maximum problem. Both analytical and simulation results clearly demonstrate the superiority of our algorithm.
21
Dhawan, Divya, e Neena Gupta. "Performance Analysis of Post Compensated Long Haul High Speed Coherent Optical OFDM System". International Journal of Electrical and Computer Engineering (IJECE) 7, n. 1 (1 febbraio 2017): 160. http://dx.doi.org/10.11591/ijece.v7i1.pp160-168.
Abstract (sommario):
<p>This paper addresses the performance analysis of OFDM transmission system based on coherent detection over high speed long haul optical links with high spectral efficiency modulation formats such as Quadrature Amplitude Modulation (QAM) as a mapping method prior to the OFDM multicarrier representation. Post compensation is used to compensate for phase noise effects. Coherent detection for signal transmitted at bit rate of 40 Gbps is successfully achieved up to distance of 3200km. Performance is analyzed in terms of Symbol Error Rate and Error Vector Magnitude by varying Optical Signal to Noise Ratio (OSNR) and varying the length of the fiber i.e transmission distance. Transmission performance is also observed through constellation diagrams at different transmission distances and different OSNRs.</p>
22
Feng, Chengxu, Yasong Luo, Jianqiang Zhang e Houpu Li. "An OFDM-Based Frequency Domain Equalization Algorithm for Underwater Acoustic Communication with a High Channel Utilization Rate". Journal of Marine Science and Engineering 11, n. 2 (14 febbraio 2023): 415. http://dx.doi.org/10.3390/jmse11020415.
Abstract (sommario):
The underwater acoustic communication technique for high-speed and highly reliable information transmission in the ocean has been one of the popular research focuses facing the fast-growing information technology sector and the accelerating development of ocean resources. In order to achieve a high information transmission rate with limited underwater acoustic channel bandwidth, researchers have paid much attention to the underwater acoustic communication technique based on orthogonal frequency division multiplexing (OFDM). A traditional OFDM-based frequency domain equalization algorithm relies on cyclic prefixes for the effective resistance to the multipath effect of an underwater acoustic channel. However, a redundant cyclic prefix may lead to a severe waste of energy and bandwidth in the underwater acoustic system if it is too long. The high utilization rate of OFDM signal channel will not be practically achieved in this case. Based on the limitations of the existing frequency domain equalization algorithm, this paper studied the influence of the multipath effect on the OFDM signal transmission. Subsequently, the principles of the OFDM-based frequency domain equalization were further explored for an improved structural model design of the communication system. On this basis, a novel frequency domain adaptive equalization algorithm was put forward. In addition, the proposed algorithm was optimized to address the problem of increased computation. The simulation results proved that the novel frequency domain equalization algorithm delivers a better symbol error ratio than the existing algorithm, and the compensation for the multipath effect through frequency selective fading. The proposed algorithm can realize the information transmission at a low symbol error ratio when fewer cyclic prefixes are used, so that it takes up a lower number of channels with cyclic prefixes in the OFDM communication system.
23
Wang, Chanfei, Jiai He e Haiyan Chen. "Decision-Feedback Aided Multiple-Symbol Differential Detection in Two-Way Relay Transmission". Mathematical Problems in Engineering 2019 (18 luglio 2019): 1–7. http://dx.doi.org/10.1155/2019/8595091.
Abstract (sommario):
In this paper, noncoherent transmission algorithms are proposed in a two-way relay transmission (TWRT), where differential space-time block codes based multiple-symbol differential detection (MSDD) is performed. Specifically, generalized likelihood ratio test aided MSDD (GLRT-MSDD) is developed with the exhaustive search in the TWRT. In order to solve the challenging problem of high complexity, the GLRT-MSDD model is reformulated and a decision-feedback aided MSDD (DF-MSDD) model is derived. Furthermore, performance analysis and the simulations confirm that the proposed DF-MSDD provides solid bit error-rate performance with a lower complexity than GLRT-MSDD in the TWRT.
24
Nazarov, L. E. "//". Радиотехника и электроника 68, n. 9 (1 settembre 2023): 873–78. http://dx.doi.org/10.31857/s003384942309019x.
Abstract (sommario):
A description of the algorithm for optimal symbol-by-symbol reception of signal structures based on block noise-resistant codes in non-binary Galois fields is given. It is shown that the basis of this algorithm is the fast spectral transformation algorithm in the Walsh–Hadamard basis with the dimension of the Galois field. It is shown that the resulting complexity of the analyzed character-by-character reception algorithm is determined by the dimension of the dual code, which determines the prospects of its application for block noise-resistant codes with a high code rate (with low redundancy). The results of modeling a character-by-symbol reception algorithm are presented in order to study noise immunity for a number of frequency-efficient digital signals with quadrature-amplitude and amplitude-phase manipulations (with frequency coefficient efficiencies of 3, 4 and 6 bps/Hz) in combination with a parity check code. It is shown that the use of a symbol-by-symbol reception algorithm provides an energy gain of up to 1.5...3.0 dB in relation to the transmission and reception of the considered series of signals without coding.
25
Mendelson, М., V. Egorov e D. Kopylov. "AFM Signals Coding When Transmitting a Fractional Number of Bits per Symbol". Proceedings of Telecommunication Universities 9, n. 4 (20 settembre 2023): 34–43. http://dx.doi.org/10.31854/1813-324x-2023-9-4-34-43.
Abstract (sommario):
The article proposes a simple method from the point of view of computational costs for encoding a fractional number of bits per symbol with amplitude-phase modulation (APM). The presentation is performed in relation to the case when it is necessary to form the value of the specific transmission rate with an accuracy of up to a quarter of a bit per symbol. Algorithms for the operation of the encoder and decoder, the formation of a synchro signal and the amount of energy gain achieved by using this method are given. The proposed coding method was used in the development and modernization of high-speed modems, the tests of which confirmed the reliability of the results obtained.
26
Alwan, Saib Thiab, Omar Abdulkareem Mahmood e Tahreer Mahmood. "Generate high data rate of optical carries by using nanomaterial graphene in slab waveguide". Curved and Layered Structures 9, n. 1 (1 gennaio 2022): 187–92. http://dx.doi.org/10.1515/cls-2022-0015.
Abstract (sommario):
Abstract Single mode is one of the most practical applications in microwave propagations because of its high mode resolution and low transmission loss. In this paper, the single mode graphene material was implemented in slab waveguide to study the performance and optical properties of graphene material; the parameters that affect these models were found to be the cut-off frequency, attenuation wavenumbers, modes numbers, skin depth, angles incident, and propagation wave numbers. The effectiveness of these factors was simulated and analyzed using MATLAB software program. In this paper, the carriers were generated using nano-graphene; the optical carrier source provided seven carriers with the frequency spacing of 4.9682 GHz. After splitting the carriers using optical demultiplexer, these carriers were modulated independently using optical Quadrature phase shift keying (QPSK) modulators at symbol rate equal to 4.9682 Gsymbol/s; this matches the frequency spacing of the carriers. Under this argument, the total data rate was equal to 2*7*4.9682 Gsymbol/s = 69.5548 Gbit/s, and the total bandwidth was 34.774 GHz. These carriers were found to work in optical communication with high data rate.
27
Xia, Li Min, Xian Zhou, Dong Yan, Na Na Zhang e Xiao Yun Wu. "Nearby Phase Search Algorithm with Reduced Complexity for Higher Order QAM Formats". Advanced Materials Research 760-762 (settembre 2013): 1869–73. http://dx.doi.org/10.4028/www.scientific.net/amr.760-762.1869.
Abstract (sommario):
This paper proposes a nearby phase search (NPS) algorithm based on BPS estimation algorithm in optical coherent receivers. And its suitable for arbitrary multi-level modulation. Making use of the continuity of phase change, the proposed NPS algorithm is applied to process nearby symbols by taking the pre-estimation phase of each symbol block as reference point. Compared to the traditional blind phase search (BPS) algorithm and its improved two-stage BPS algorithm, the performance of the proposed NPS algorithm is greatly improved in ultra-high speed coherent optical transmission system. By the simulation, the effectiveness and feasibility of the proposed algorithm are demonstrated in 28GBaud 16-QAM and 64-QAM system. Its shown that the computational complexity of the NPS algorithm greatly reduces in the guarantee of laser line width tolerance and bit error rate.
28
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.
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.
29
Peng, Yaqiu, e Mingqi Li. "Discrete Fourier Transform-Based Block Faster-Than- Nyquist Transmission for 5G Wireless Communications". Applied Sciences 10, n. 4 (14 febbraio 2020): 1313. http://dx.doi.org/10.3390/app10041313.
Abstract (sommario):
Faster-than-Nyquist (FTN) signaling is regarded as a potential candidate for improving data rate and spectral efficiency of 5G new radio (NR). However, complex detectors have to be utilized to eliminate the inter symbol interference (ISI) introduced by time-domain packing and the inter carrier interference (ICI) introduced by frequency-domain packing. Thus, the exploration of low complexity transceiver schemes and detectors is of great importance. In this paper, we consider a discrete Fourier transform (DFT) block transmission for multi-carrier FTN signaling, i.e., DBT-MC-FTN. With the aid of DFTs/IDFTs and frequency domain windowing, time- and frequency domain packing can be implemented flexibly and efficiently. At the receiver, the inherent ISI and ICI can be canceled via a soft successive interference cancellation (SIC) detector. The effectiveness of the detector is verified by the simulation over the additive white Gaussian noise channel and the fading channel. Furthermore, based on the characteristics of the efficient architecture of DFT-MC-FTN, two pilot-aided channel estimation schemes, i.e., time-division-multiplexing DBT-MC-FTN symbol-level pilot, and frequency-division-multiplexing subcarrier-level pilot within the DBT-MC-FTN symbol, respectively, are also derived. Numerical results show that the proposed channel estimation schemes can achieve high channel estimation accuracy.
30
Gao, Hui Juan, e Yan Liu. "New Dual-Mode FSE Suitable for High-Order QAM Signals". Advanced Materials Research 760-762 (settembre 2013): 478–82. http://dx.doi.org/10.4028/www.scientific.net/amr.760-762.478.
Abstract (sommario):
In the digital transmission system, constant modulus algorithm (CMA) is a famous blind equalization to overcome the inter-symbol interference without the aid of training sequences. But for the non-constant modulus signals such as higher-order QAM signals, the CMA just achieve moderate steady-state mean square error (MSE). So a new dual-mode fractionally-spaced equalization (FSE) suitable for high-order QAM signals is proposed, which makes full use of the character which is that the high-order QAM signals have the different modulus. This algorithm uses the FSE based on CMA as the basal mode and in the second mode it uses the FSE based on variable modulus algorithm. The simulation results show that compared with CMA the proposed algorithm has faster convergence rate and lower steady-state mean square error.
31
Fu, Tao, Yanfeng Yu e Cheng Liu. "SCWOMP Recovery Algorithm for 5G MIMO Communication Symbol Detection". Journal of Computer Networks and Communications 2023 (14 luglio 2023): 1–10. http://dx.doi.org/10.1155/2023/1374601.
Abstract (sommario):
In order to solve the problem of small capacity and high energy consumption in China’s 5G communication technology system, the research proposes that based on the segmented weakly orthogonal matching pursuit (SWOMP) algorithm, it is combined with the compressed sensing matching pursuit algorithm to form a segmented backtracking weak selection positive algorithm and Cross Match Tracking (SCWOMP) algorithm. First, the sparseness of MIMO system technology and its transmission structure is analyzed. Then, the new model is built after comparing with other algorithms, and the problem of overestimating the low recovery probability in the calculation process is improved by the backtracking of the algorithm and the improvement of the angle of the atomic column selection, so as to reduce the number of iterations and improve the performance of the algorithm. The results show that, in the performance comparison of different sampling points under different compressed sensing recovery algorithms, the recovery probability of the SCWOMP algorithm is the best, and when the number of sampling points is 80, although the fixed step size of the SCWOMP algorithm is different, there is recovery. The probability has a maximum value, close to 1. Then, the improved compressed sensing recovery algorithm is simulated and analyzed. When the pruning coefficient is 0.5 and the number of sampling points is 80, the reconstruction rate has a maximum value, and when other algorithms reach the maximum reconstruction rate, the number of sampling points (M) is significantly greater than that of the SCWOMP algorithm. An increase in the rate of reduction of the reconstruction probability of the SCWOMP algorithm is significantly lower than that of other algorithms; when sparsity is equal to 70, the reconstruction probability becomes 0, indicating that SCWOMP has a wider reconfigurable range and has a significant performance effect. This shows that the proposed SCWOMP algorithm has the best detection performance for 5G communication symbol detection, which can effectively increase the capacity of the system and better promote technology.
32
Haque, Md Dulal, Md Milon Rana e Tajkuruna Akter Tithy. "PAPR Reduction and Bit Error Rate Evaluation in OFDM System using Hybrid Techniques". International Journal on AdHoc Networking Systems 12, n. 3 (31 luglio 2022): 1–19. http://dx.doi.org/10.5121/ijans.2022.12301.
Abstract (sommario):
Orthogonal frequency division multiplexing (OFDM) has become an important component of waveform generation in wideband transmission. it's a superior technology for the high-speed rate of wired and wireless communication systems. Currently, multiple-input multiple-output orthogonal frequency division multiplexing (MIMO OFDM) systems are crucial wireless communication systems like 4G and 5G networks & tactical communication. The OFDM has many advantages over other techniques like its high capacity and immunity against multipath fading channels. However, one amongst the foremost drawbacks of the OFDM system is that the high-peak-to-average power ratio (PAPR) that leads the system to provide in-band distortion and out-of-band radiation and reduces its efficiency. This problem increases with a rise within the number of transmit antennas. Therefore, it's highly desirable to cut back the PAPR of an OFDM signal. For this, numerous techniques are proposed to beat the PAPR problem like i) Selective mapping (SLM) ii) Partial transmit sequence (PTS), iii) Clipping, iv) Clipping and filtering. All of those are reduced the PAPR by generating alternative subcarrier vector that are statistically independent OFDM symbols for a given data frame and transmitting the symbol with rock bottom peak power. During this paper we also proposed, some hybrid techniques. The hybrid techniques are the technique of clipping is employed in conjunction with SLM and PTS to cut back computational complexity. And also the combination of SLMPTS to scale back PAPR. Simulations are acquainted with analyze the efficiency of the techniques used which signifies OFDM to be providing much better PAPR reduction and a way better Bit Error Rate (BER). it's shown in simulation results that the proposed scheme performs well reducing PAPR. But the proposed scheme is more complex than the prevailing techniques.
33
Wen, Guo Guan, Qing Ming Yi e Min Shi. "Application of Programmable Pre-Emphasis in LVDS Driver". Applied Mechanics and Materials 380-384 (agosto 2013): 3043–46. http://dx.doi.org/10.4028/www.scientific.net/amm.380-384.3043.
Abstract (sommario):
As demand for data rate continues to increase, new problem of LVDS start to come out, such as signal integrity. Those problems are primarily caused by frequency-dependent loss in transmission line. The purpose of pre-emphasis is to apply intentional overdriving to the signal and get it back to the original signal with the proper weight, thereby compensating for the ISI from the nearby data symbol. In order to avoid over-emphasis we propose a programmable pre-emphasis adapting to different situation, and finish the prototype which can improve the transmission bandwidth more effectively, achieving high-speed data transmission.
34
Liu, Yanyan, Weigang Chen, Anguo Wang e Changcai Han. "Combination of High-Order Modulation and Non-Binary LDPC Codes over GF(7) for Non-Linear Satellite Channels". Electronics 8, n. 12 (22 novembre 2019): 1396. http://dx.doi.org/10.3390/electronics8121396.
Abstract (sommario):
High-order modulations are necessary to improve the bandwidth efficiency of the satellite communication system. However, the non-linear characteristic of satellite channels limits the application of high-order modulations. In this paper, we propose a new 7-point constellation which is expected to be effectively applied to the satellite communication system, and combine it with non-binary low-density parity-check (NB-LDPC) codes over Galois field GF(7) to guarantee the reliability of the data transmission. The exact expression for the average symbol error probability (SEP) of 7-order quadrature amplitude modulation (7-QAM) over the Additive White Gaussian Noise (AWGN) channel is derived, and the non-linear distortion over satellite channels is also analyzed. Simulation results reveal that, compared with the traditional 8-order phase-shift keying (8-PSK), the 7-QAM method can achieve about 3 dB gain over the AWGN channel without channel coding at symbol error rate (SER) of 10 - 6 . Moreover, the proposed combined coded modulation scheme also has better SER performance than the NB-LDPC coded 8-PSK modulation scheme over the non-linear satellite channel.
35
Hu, Chunyuan, Yujie Lin, Jianguo Li, Xiangyuan Bu e Jianping An. "Near-Nyquist-Limit Optical Communication and Ranging Method Based on Waveform Matched PPM". Electronics 11, n. 4 (13 febbraio 2022): 565. http://dx.doi.org/10.3390/electronics11040565.
Abstract (sommario):
Deep-space optical communication and ranging technologies have attracted much attention for satellite-to-earth and moon-to-earth exploration. In integrated communication and ranging scenarios, non-integer oversampling factors are employed to improve the ranging performance, which can cause accumulated timing errors. We propose a novel pulse position modulation (PPM) symbol decision method based on waveform matching to reduce the impact of accumulated timing errors near the Nyquist sampling limit. Simulation results demonstrate that the ranging accuracy can reach 2.6 and 0.52 mm at sampling rates of 625 Msps and 2.5 Gsps, respectively. The proposed symbol decision method has a gain of over 1.1 dB compared with the traditional method at the bit error rate (BER) of less than 10−6. The experimental results verify that this method can achieve high-precision measurements of distance and reliable transmission of information.
36
Liu, Haike, Yang You, Lifeng Shi e Huajiian Zhang. "Multi-domain united link adaptation technique in high-throughput satellite communication system". Journal of Physics: Conference Series 2469, n. 1 (1 marzo 2023): 012027. http://dx.doi.org/10.1088/1742-6596/2469/1/012027.
Abstract (sommario):
Abstract Under the condition of using the same frequency resources, the communication capacity of high-throughput satellites is tens or even hundreds of times higher than that of traditional satellites. Compared with traditional satellites, high-throughput satellites have a large capacity, high speed, and anti-interference characteristics. However, the high-throughput satellite communication link using Ku/Ka-band is vulnerable to weather factors such as rain attenuation, so the system should have a control mechanism to achieve fade countermeasures. The existing methods include transmission power adjustment, mod cod adaptive adjustment, carrier symbol rate adjustment, etc. In this paper, various technical means are comprehensively used to compare and analyze the effect of combined control and propose a multi-domain united link adaptation technique to optimize link availability and resource utilization.
37
L, Sruthy, L. Bharathi e P. Malini. "Selective Spanning With Fast Enumeration Algorithm for MIMO". International Journal of Emerging Research in Management and Technology 6, n. 10 (20 ottobre 2017): 79. http://dx.doi.org/10.23956/ijermt.v6i10.70.
Abstract (sommario):
Multiple input multiple output system have been emerged technology to increase channel capacity and a technical breakthrough for high data rate wireless transmission. The main objective of MIMO system is to obtain low Symbol Error Rate (SER) and acceptable computational complexity. The MIMO system cannot be implemented due to complexity problem. The complexity of MIMO system can be reduced by using different detector algorithms. In this paper, the performance of MIMO system over AWGN (Additive White Gaussian Noise) with ZF, MMSE, SD, K best algorithm and SSFE are analyzed using different antenna configuration. The Bit Error Rate performance of all detectors are studied for 16QAM modulation technique using AWGN channel for the analysis purpose and their effect on BER (Bit Error Rate) have been presented.
38
Mishra, Manish Kumar, e Ritesh Kumar Mishra. "Performance Analysis of HSTC Network with Non-Static Terrestrial Nodes in a Fading Environment". Revue d'Intelligence Artificielle 36, n. 3 (30 giugno 2022): 363–71. http://dx.doi.org/10.18280/ria.360303.
Abstract (sommario):
In this paper, Hybrid satellite-terrestrial systems (HSTC) are preferred in dynamic type environments with high mobility of nodes due to the performance enhancement features in multiple relay-based selective decode-and-forward (DF) approach. Because of the satellite link, aerial satellite to destination and satellite to relay links, are not the same due to time-selective shadowed Rician fading. Time-selective Rician fading depends on parameters like the angle of elevation of the satellite, the terrestrial relay node, and the node destination links, considered to be distinctively time-selective Nakagami faded. Here, per-frame average symbol error rate (SER) and outage probability are derived in a closed-form expression with consideration of M-ary PSK modulated symbols transmission. After evaluation, it was detected that the system performance is significantly degraded due to the time-varying nature of the links (dynamic environment). After various simulations and calculations, it was established that the error rate of the HSTC is significantly low by increasing the elevation angle of the satellite on the relay point. The performance enhancement can be observed by enhancing the satellite angle at the destination node of user equipment.
39
Uddin, Jia, Mohammed Faisal, Md Facihul Azam e A. F. M. Muzahidur Rahman. "Performance Analysis of Multicarrier Code Division Multiple Access over Rayleigh Fading Channel". Advanced Materials Research 457-458 (gennaio 2012): 985–88. http://dx.doi.org/10.4028/www.scientific.net/amr.457-458.985.
Abstract (sommario):
Recently, multi-carrier transmission schemes have been introduced into Code Division Multiple Access (CDMA) systems to gain advantages for high data rate transmission as well as security. Due to pseudorandom code there is no chance to Inter Symbol Interference (ISI). There are different techniques to mitigate multipath fading. One of the method is to transmit identical narrowband direct-sequence (DS) waveforms in parallel over a number of sub-channels using frequency diversity. Implementation this multi-carrier modulation technique in CDMA system is known as multi-carrier CDMA (MC-CDMA). In Rayleigh fading channel, due to multi-carrier modulation, when one subcarrier goes deep fade another subcarrier may remain safe. Therefore it combats multi-path fading and signal can be received in low bit error rate.
40
DANG, LE KHOA, HUU PHUONG NGUYEN, LE NGUYEN BINH e DUC NHAN NGUYEN. "SIMULINK MODEL AND FPGA-BASED OFDM COMMUNICATION SYSTEM: A SIMULATION AND HARDWARE INTEGRATED PLATFORM". International Journal of Modeling, Simulation, and Scientific Computing 01, n. 03 (settembre 2010): 369–404. http://dx.doi.org/10.1142/s1793962310000250.
Abstract (sommario):
Ultra-broadband networks are currently attracting significant interests in employing wireless access and optical fiber access to the home and to the building at symbol rate reaching Gb/s. OFDM is a multicarrier modulation technique and considered to offer significant reduction of the data symbol to be carried per carrier channel, especially in ultra-high speed optical communications with bit rate reaching 100 Gb/s or even higher. This paper thus presents a novel and generic OFDM system employing both MATLAB Simulink and FPGA-based development software platform for simulation as well as hardware implementation for the generation and detection of OFDM signals for wireless and optical communications transmission media. Although the transmission medium is modeled with delay distortion filter in the baseband, this model would be valid for passband signals as the amplitude is represented by complex amplitude whose phase would be the phase of the carrier. The Simulink and hardware models presented hereunder are scalable to much higher speed allowing possible implementation in multi-Giga samples per second electronic processors. The sub-systems of the OFDM transmitter and receiver are presented to demonstrate the feasibility of such models for ultra-wideband communication systems such as wireless access and long haul optical fiber communication backbone networks.
41
Fayadh, Rashid Ali, Mohd Fareq Abd Malek, Hilal Adnan Fadhil e Norshafinash Saudin. "Performance Evaluation of Adaptive Indoor Matched Rake Receiver Using Multiple-Combining Techniques". Applied Mechanics and Materials 699 (novembre 2014): 921–30. http://dx.doi.org/10.4028/www.scientific.net/amm.699.921.
Abstract (sommario):
This paper discusses the enhancement of the wireless rake receiver for high speed and short distance indoor ultra wideband (UWB) propagation with line-of sight (LOS) and non line-of sight (NLOS) channel models. The proposed matched rake receiver uses three main combining techniques, maximum ratio combining (MRC), equal gain combining (EGC), and selective combining (SC) to capture most of the energy of the multi-path components (MPCs). When the wireless communication systems work with high capacity and high speed in transmission and reception scenarios, there will be a serious challenge defined as inter-symbol interference (ISI) during the reception process. The ISI causes increasing in the bit error rate (BER) when the wireless communication systems work with high bit rate propagation. The matched rake receiver scheme was designed to suppress ISI by maximizing the signal to noise ratio (SNR) before constructing the desired signal in decision circuit and effectively the system enhancement is improved. After adding additive white Gaussian noise (AWGN) to the received signal, the improvement is cleared comparing with the theoretical results that has no AWGN. During the comparison of the simulation results, MRC partial rake receiver of less complexity showed better performance than the EGC and SC rake receivers.
42
Zhu, Guijun, Xiukai Ruan e Zhili Zhou. "Dispersion characteristics and compensation in the POLMUX coherent optical communication system". Modern Physics Letters B 31, n. 19-21 (27 luglio 2017): 1740054. http://dx.doi.org/10.1142/s0217984917400541.
Abstract (sommario):
The trend of high-speed optical communication is to realize large capacity, fast speed and long haul transmission. However, the dispersion in an optical fiber link can cause signals distortion or even inter symbol interference (ISI). With increasing signal rate and transmission distance in the optical communication system, the development of high-speed optical fiber communication is restricted seriously. This paper is focusing on the dispersion characteristics and compensation of the polarization multiplexing (POLMUX) coherent optical communication system: (i) to study on dispersion theoretically, e.g., chromatic dispersion (CD), polarization mode dispersion (PMD) and dispersion tolerance; (ii) to analyze and compare the performance of dispersion with various 16-ary modulation formats; (iii) to compensate dispersion by the classical dispersion compensation methods.
43
Qi, Junwei, Sergey B. Makarov, Mingxin Liu, Beiming Li e Wei Xue. "Research on an Optimization Method for a Partially Responsive Continuous Phase Modulated (CPM) Signal Based on an Optimal Generic Function". Symmetry 11, n. 9 (3 settembre 2019): 1114. http://dx.doi.org/10.3390/sym11091114.
Abstract (sommario):
This paper establishes an optimal generic function model in order to obtain a continuous phase modulated (CPM) signal with a smoother phase modulation function. This is achieved by finding the solution to the symbol signals at different lengths of the CPM function. In the solution process, the unknown amount that needs to be solved is reduced by using the even function symmetry characteristic of the signal to be solved. For each different form of the signal, the time domain form of the CPM function and the corresponding normalized energy spectral density are compared under the influence of the phase modulation signal length and the generic function parameter n. The data transmission rate is improved by introducing inter-symbol interference, and the modulation process is realized using six-way parallel transmission when the CPM function is 6T. The simulation results show that the CPM function obtained by establishing an optimal generic function model has high-quality time-frequency characteristics. The real-time phase trajectory and the high-order derivative are both continuous, and the modulated signal has constant envelope characteristics. The CPM function has a fast rolling-off in the frequency domain and small out-of-band radiation, which greatly improves the characteristics of the frequency band utilization.
44
Al-Asady, Heba Abdul-Jaleel, Hassan Falah Fakhruldeen e Mustafa Qahtan Alsudani. "Channel estimation of OFDM in C-band communication systems under different distribution conditions". Indonesian Journal of Electrical Engineering and Computer Science 23, n. 3 (1 settembre 2021): 1778. http://dx.doi.org/10.11591/ijeecs.v23.i3.pp1778-1782.
Abstract (sommario):
<p>Orthogonal frequency division multiplexing (OFDM) is a transmission system that uses multiple orthogonal carriers that are sent out at the same time. OFDM is a technique for mobile and wireless communication that has high-efficient frequency utilization, high data-rate transmission, simple and efficient implementation using the fast Fourier transform (FFT) and the inverse fast Fourier transform (IFFT), and reduces inter symbol interference (ISI) by inserting cyclic prefix (CP). One of the most important approaches in an OFDM system is channel estimation. In this paper, the orthogonal frequency division multiplexing system with the Rayleigh channel module is analyzed for different areas. The proposed approach used large numbers of subcarriers to transmit the signals over 64-QAM modulation with pilot add channel estimation. The accuracy of the OFDM system is shown in the measuring of the relationships of peak power to the noise ratio and bit error rate.</p>
45
Kupferman, Judy, e Shlomi Arnon. "Communication Systems Performance at mm and THz as a Function of a Rain Rate Probability Density Function Model". Sensors 22, n. 16 (20 agosto 2022): 6269. http://dx.doi.org/10.3390/s22166269.
Abstract (sommario):
6G is already being planned and will employ much higher frequencies, leading to a revolutionary era in communication between people as well as things. It is well known that weather, especially rain, can cause increased attenuation of signal transmission for higher frequencies. The standard methods for evaluating the effect of rain on symbol error rate are based on long-term averaging. These methods are inaccurate, which results in an inefficient system design. This is critical regarding bandwidth scarcity and energy consumption and requires a more significant margin of effort to cope with the imprecision. Recently, we have developed a new and more precise method for calculating communication system performance in case of rain, using the probability density function of rain rate. For high rain rate (above 10 mm/h), for a typical set of parameters, our method shows the symbol error rate in this range to be higher by orders of magnitude than that found by ITU standard methods. Our model also indicates that sensing and measuring the rain rate probability is important in order to provide the required bit error rate to the users. This will enable the design of more efficient systems, enabling design of an adaptive system that will adjust itself to rain conditions in such a way that performance will be improved. To the best knowledge of the authors, this novel analysis is unique. It can constitute a more efficient performance metric for the new era of 6G communication and prevent disruption due to incorrect system design.
46
Nguyen, Huy, Nam Tuan Le, Nguyen Cong Hoan e Yeong Min Jang. "Real-Time Mitigation of the Mobility Effect for IEEE 802.15.4g SUN MR-OFDM". Applied Sciences 9, n. 16 (11 agosto 2019): 3289. http://dx.doi.org/10.3390/app9163289.
Abstract (sommario):
In order to develop wireless sensor networks, which are defined by the IEEE 802.15.4 specification, researchers are considering low-power wide-area networks (LPWAN) due to their advantages of being long range, low power, low cost, and highly mobile. The issue of mobility is covered in the IEEE 802.15.4g standard for supporting a smart utility network (SUN), which is mainly controlled by orthogonal frequency-division multiplexing (OFDM) modulation. In a high mobility scenario, inter-carrier interference is a primary factor in reducing the performance of OFDM transmissions due to the destruction of the subcarrier component’s orthogonality. This paper analyzes the mobility effect in multi-rate multi-regional orthogonal frequency-division multiplexing (MR-OFDM) for low-power wide-area networks in general, and the SUN MR-OFDM system in particular. As mentioned in standard 802.15.4 2015, IEEE 802.15.4g MR-OFDM is one of the low-power wide-area (LPWA) technologies in which energy optimization problems are of first priority. We are especially interested in simple technologies that provide high efficiency. Therefore, we propose a highly adaptive method that uses the cyclic prefix to mitigate the mobility effect in real time. At a symbol frames interval of 120 us, the Doppler shift effect from the mobility of the MR-OFDM system adapted smoothly. This is not the best method to mitigate Doppler shift but it is a simple method that suits the LPWA network. The proposed scheme clearly simulated the mobility of the MR-OFDM system, and had the advantage of using a cyclic-prefix with a bit error rate performance through Additive White Gaussian Noise (AWGN) and the Rician channel of Matlab.
47
Zheng, Zi Wei. "Iterative Channel Estimation Scheme for the WLAN Systems with the Multiple-Antenna Receivers". Advanced Engineering Forum 6-7 (settembre 2012): 871–75. http://dx.doi.org/10.4028/www.scientific.net/aef.6-7.871.
Abstract (sommario):
Alleviate the multipath delay spread and suitable for broadband transmission efficiency, orthogonal frequency division multiplexing wireless local area network (WLAN) is widely used to assist inverse fast Fourier transform and fast Fourier transform operation domain. Orthogonal frequency division multiplexing is a blow to the broadcast channel multipath fading and high data throughput, transmission, wireless fading channel method, which is widely used to support high performance bandwidth-efficient wireless multimedia services. Several times in the transmitter and receiver antenna technology allows data transfer rate and spectrum efficiency and the use of multiple transmit antennas and multiple receive antennas through spatial processing. High-precision channel estimation scheme is very important wideband multi-carrier orthogonal frequency complex WLAN systems use multiple antenna receiver based division of labor and the overall multi-carrier orthogonal frequency multiplexing division of performance-based WLAN system is to crucial antenna to receive the symbol error rate. In this article, the iterative channel estimation scheme proposed multi-carrier orthogonal frequency division multiplexed using multiple antennas receiver-based WLAN system.
48
Ra, HyungIn, Changhyun Youn e Kiman Kim. "High-Reliability Underwater Acoustic Communication Using an M-ary Cyclic Spread Spectrum". Electronics 11, n. 11 (26 maggio 2022): 1698. http://dx.doi.org/10.3390/electronics11111698.
Abstract (sommario):
Multipath propagation, frequency selective fading, low-propagation velocity, and narrow bandwidth are all characteristics of underwater acoustic channels. Doppler shifts and diffusions can occur as a result of the low transmission speed of an acoustic signal, which can be caused by the movement of ocean currents or the transceiver. Furthermore, frequency selective fading and excessive noise interference can disrupt underwater acoustic communication on a continual basis. Because of its high anti-interference ability and high confidentiality, spread spectrum technology is commonly adopted in underwater acoustic communications. Although the direct sequence spread spectrum method has a low data rate, it is advantageous in a multipath propagation channel environment or an environment with a low signal-to-noise ratio (SNR). This advantage is suitable for long-distance transmission or LPD (Low Probability of Detection) communication, and the direct sequence spread spectrum method is applied. In this paper, we propose a highly reliable M-ary cyclic spread spectrum technique by superimposing the M-ary spread spectrum, an extension of the direct sequence spread spectrum technique, and cyclic shift keying. Furthermore, by estimating the Doppler frequency using M-ary spread spectrum codes and performing synchronization correction of the ensuing symbol based on the estimation results, higher performance can be attained. Simulations and experiments showed that the M-ary cyclic spread spectrum method can reduce Doppler estimation and synchronization error accumulation while maintaining a high data rate. Furthermore, the MCSS method had a lower bit error rate than the standard spread spectrum method.
49
Zhan, Yongzheng, Tuo Li, Xiaofeng Zou, Qingsheng Hu, Lianming Li e Lu Zhang. "41.6 Gb/s High-Depth Pre-Interleaver for DFE Error Propagation in 65 nm CMOS Technology". Electronics 12, n. 18 (16 settembre 2023): 3912. http://dx.doi.org/10.3390/electronics12183912.
Abstract (sommario):
A high-speed, high-depth pre-interleaver in the proposed symbol pre-interleaving Bit MUX (PBM) was implemented to mitigate decision feedback equalizer (DFE) error propagation in a 400 G Ethernet Serializer–Deserializer (SerDes) interface. Based on the SerDes interface link architecture with 5-tap DFE, the performance of the PBM under DFE error propagation was simulated theoretically, which could obtain an interleaving gain of 0.35 dB. In the pre-interleaver, in order to significantly increase the transmission rate while keeping the larger interleaving depth, characteristic polynomial parallelization with the logic expansion method and register-based memory with interleaving technology were adopted. Finally, the pre-interleaver was fabricated with 65 nm CMOS technology, with a total area of 0.615 mm2, including the I/O pad. The measurement results show that the horizontal opening degree of the output signal can reach 0.925 UI at the data rate of 41.6 Gb/s. The total power consumption is 38.52 mW at the supply voltage of 1.2 V and frequency of 1.3 GHz.
50
Muduli, Sudha Subhalaxmi, Laxmikanta Padhy, Swadhin Polei e Tusharkant Panda. "Performance Analysis of a High-Speed Optical Transmission System Using Various Pulse Generator". ECS Transactions 107, n. 1 (24 aprile 2022): 7351–63. http://dx.doi.org/10.1149/10701.7351ecst.
Abstract (sommario):
The future generation technology needs network expansion, large bandwidth capacity, and modern application development. Due to dielectric in nature, having electromagnetic immunity, having larger bandwidth, and being a lightweight cable, the demand for optical fiber has grown expeditiously. ISI (Inter Symbol Interference) hampers the performance of optical communication drastically. It induces a superabundant increment in pulse duration, rolling out in time and space engrossed by the pulse as it propagates. As the pulse propagate along the optical fiber, this spread can be so enormous that a photo detector can no longer discriminate boundaries between pulses. Due to ISI, path loss increases rapidly and causes broadening of pulses and achieving high data rates becomes difficult. To reduce the effect of ISI pulse shaping technique is used. In this paper the channeling performance of optical fiber and DCF is estimated by using different pulse generator. Here we collated the performance of APD photo diode and PIN photo diode value in terms of Q-Factor and Bit Error Rate in the eye diagram. We have used a DCF to mitigate the effect of dispersion produced in the channel.