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Academic literature on the topic 'Orthogonal Frequency Division Multiplexing (OFDMA)'
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Journal articles on the topic "Orthogonal Frequency Division Multiplexing (OFDMA)"
1
Al-Rawi, M. "Performance analysis of OFDMA and SC-FDMA." International Review of Applied Sciences and Engineering 8, no. 2 (2017): 113–16. http://dx.doi.org/10.1556/1848.2017.8.2.2.
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The main challenge in any high-speed digital communication system is how to maximize the data rate with minimizing the bit error rate. Several techniques have been developed to achieve this point. Some of these techniques are orthogonal frequency division multiplexing (OFDM), single-carrier frequency domain equalization (SC-FDE), orthogonal frequency division multiple access (OFDMA), and single-carrier frequency division multiple access (SC-FDMA). These four techniques are described briefly in this paper. Also, the paper measures the performances of OFDMA and SC-FDMA systems over international telecommunication union (ITU) vehicular-A channel using minimum mean square error (MMSE) equalization. Simulation results show that the performances with interleaved mapping outperform that with localized mapping. Also, the performances with quadrature phase shift keying (QPSK) are better than that with 16-ary quadrature amplitude modulation (16QAM). In addition, the performance of SC-FDMA is better than that of OFDMA, when QPSK is used, but the latter is little bit better than that of SC-FDMA when 16QAM is used.
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Ahmed, Mohamed H., Octavia A. Dobre, and Rabie K. Almatarneh. "Analytical Evaluation of the Performance of Proportional Fair Scheduling in OFDMA-Based Wireless Systems." Journal of Electrical and Computer Engineering 2012 (2012): 1–12. http://dx.doi.org/10.1155/2012/680318.
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This paper provides an analytical evaluation of the performance of proportional fair (PF) scheduling in Orthogonal Frequency-Division Multiple Access (OFDMA) wireless systems. OFDMA represents a promising multiple access scheme for transmission over wireless channels, as it combines the orthogonal frequency division multiplexing (OFDM) modulation and subcarrier allocation. On the other hand, the PF scheduling is an efficient resource allocation scheme with good fairness characteristics. Consequently, OFDMA with PF scheduling represents an attractive solution to deliver high data rate services to multiple users simultaneously with a high degree of fairness. We investigate a two-dimensional (time slot and frequency subcarrier) PF scheduling algorithm for OFDMA systems and evaluate its performance analytically and by simulations. We derive approximate closed-form expressions for the average throughput, throughput fairness index, and packet delay. Computer simulations are used for verification. The analytical results agree well with the results from simulations, which show the good accuracy of the analytical expressions.
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L. N. Balai, Girraj Kumar Jangid, Ashish Kumar Sharma,. "Investigations on PAPR and SER Performance Analysis of OFDMA and SCFDMA under Different Channels." International Journal on Recent Technologies in Mechanical and Electrical Engineering 9, no. 5 (2022): 28–35. http://dx.doi.org/10.17762/ijrmee.v9i5.371.
Full textAbstract:
Code Division Multiple Access (CDMA) and Orthogonal Frequency Division Multiplexing are two multicarrier regulatory systems that have improved due to the growing demand in quick communication (OFDM). A frequency division multiplexing (FDM) plot called orthogonal frequency division multiplexing is utilized as a sophisticated multi carrier regulation approach.
 Due to its excellent spectrum efficiency and low data rate, the single carrier multiple access system (SC-FDMA) is a unique radio transmission technique that is now employed in long-term evolution (LTE) technology for uplink. When compared to OFDM, reduced peak-to-average power ratio (PAPR) and error rate technique. PAPR performance has been obtained using Matlab simulation. Techniques using variable numbers of subcarriers include SC-FDMA and OFDMA. Two various subcarrier assignment strategies have been proposed, distributed FDMA Localized FDMA and (DFDMA) (LFDMA). IFDMA, or interleaved FDMA, is a DFDMA special situation when DFT results have been distributed consistently and at the same distance. When comparing the SC-FDMA variants, we discover that Localized has a higher PAPR than interleaved (FDMA) (FDMA). We also talk about the Performance of LFDMA and IFDMA's SER (Symbol Error Rate) and found that localized (FDMA) performs better in the SER than interleaved (IFDMA) method.
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L. N. Balai, Girraj Kumar Jangid, Ashish Kumar Sharma,. "Investigations on PAPR and SER Performance Analysis of OFDMA and SCFDMA under Different Channels." International Journal on Recent Technologies in Mechanical and Electrical Engineering 9, no. 3 (2022): 28–35. http://dx.doi.org/10.17762/ijrmee.v9i3.371.
Full textAbstract:
Code Division Multiple Access (CDMA) and Orthogonal Frequency Division Multiplexing are two multicarrier regulatory systems that have improved due to the growing demand in quick communication (OFDM). A frequency division multiplexing (FDM) plot called orthogonal frequency division multiplexing is utilized as a sophisticated multi carrier regulation approach.
 Due to its excellent spectrum efficiency and low data rate, the single carrier multiple access system (SC-FDMA) is a unique radio transmission technique that is now employed in long-term evolution (LTE) technology for uplink. When compared to OFDM, reduced peak-to-average power ratio (PAPR) and error rate technique. PAPR performance has been obtained using Matlab simulation. Techniques using variable numbers of subcarriers include SC-FDMA and OFDMA. Two various subcarrier assignment strategies have been proposed, distributed FDMA Localized FDMA and (DFDMA) (LFDMA). IFDMA, or interleaved FDMA, is a DFDMA special situation when DFT results have been distributed consistently and at the same distance. When comparing the SC-FDMA variants, we discover that Localized has a higher PAPR than interleaved (FDMA) (FDMA). We also talk about the Performance of LFDMA and IFDMA's SER (Symbol Error Rate) and found that localized (FDMA) performs better in the SER than interleaved (IFDMA) method.
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Mahender, Kommabatla, Tipparti Anil Kumar, and K. S Ramesh. "PAPR Analysis of Fifth Generation Multiple Access Waveforms for Advanced Wireless Communication." International Journal of Engineering & Technology 7, no. 3.34 (2018): 487. http://dx.doi.org/10.14419/ijet.v7i3.34.19364.
Full textAbstract:
This paper describes the aspects of multiple access for emerging (5G) Wireless Communication Systems. Orthogonal Frequency Division Multiplexing (OFDM) is best suited for fourth generation (4G) but it suffers from the problem of high Peak to Average Power Ratio (PAPR) & Side band leakage. Single carrier frequency division multiple access (SC-FDMA) has worked like an alternative to OFDMA only in the uplink process and PAPR was reduced. OFDM based 4G network is not capable of supporting diverse applications and these applications can be implemented by 5G. High traffic requirements of 5G can be evaluated by using multiple access schemes, namely filter-bank multi-carrier (FBMC), universal-filtered multi-carrier (UFMC), generalized frequency-division multiplexing (GFDM). Comparison of PAPR reduction is done based on Complementary Cumulative Distribution Function (CCDF), for various multiple access 5G waveforms.
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Junejo, Naveed Ur Rehman, Mariyam Sattar, Saifullah Adnan, et al. "A Survey on Physical Layer Techniques and Challenges in Underwater Communication Systems." Journal of Marine Science and Engineering 11, no. 4 (2023): 885. http://dx.doi.org/10.3390/jmse11040885.
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In the past decades, researchers/scientists have paid attention to the physical layer of underwater communications (UWCs) due to a variety of scientific, military, and civil tasks completed beneath water. This includes numerous activities critical for communication, such as survey and monitoring of oceans, rescue, and response to disasters under the sea. Till the end of the last decade, many review articles addressing the history and survey of UWC have been published which were mostly focused on underwater sensor networks (UWSN), routing protocols, and underwater optical communication (UWOC). This paper provides an overview of underwater acoustic (UWA) physical layer techniques including cyclic prefix orthogonal frequency division multiplexing (CP-OFDM), zero padding orthogonal frequency division multiplexing (ZP-OFDM), time-domain synchronization orthogonal frequency division multiplexing (TDS-OFDM), multiple input multiple output orthogonal frequency division multiplexing (MIMO-OFDM), generalized frequency division multiplexing (GFDM), unfiltered orthogonal frequency division multiplexing (UF-OFDM), continuous phase modulation orthogonal frequency division multiplexing (CPM-OFDM), filter bank multicarrier (FBMC) modulation, MIMO, spatial modulation technologies (SMTs), and orthogonal frequency division multiplexing index modulation (OFDM-IM). Additionally, this paper provides a comprehensive review of UWA channel modeling problems and challenges, such as transmission loss, propagation delay, signal-to-noise ratio (SNR) and distance, multipath effect, ambient noise effect, delay spread, Doppler effect modeling, Doppler shift estimation. Further, modern technologies of the physical layer of UWC have been discussed. This study also discusses the different modulation technology in terms of spectral efficiency, computational complexity, date rate, bit error rate (BER), and energy efficiency along with their merits and demerits.
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Richard, E. Alwin. "Performance Analysis of OFDMA vs. NOMA in Cognitive Radio Network." International Journal for Research in Applied Science and Engineering Technology 9, no. VI (2021): 2483–88. http://dx.doi.org/10.22214/ijraset.2021.34751.
Full textAbstract:
Recent advancements in communication systems have resulted in a new class of multiple access schemes known as non-orthogonal multiple access (NOMA), the primary goal of which is to increase spectrum efficiency by overlapping data from different users in a single time-frequency resource used by the physical layer. NOMA receivers can resolve interference between data symbols from various users, hence increasing throughput. Initially, the combination of SCMA and orthogonal frequency division multiplexing (OFDM) is addressed, establishing a baseline for the overall SER performance of the multiple access strategy. Furthermore, this work suggests the merging of SCMA with generalised frequency division multiplexing (GFDM).GFDM is an intriguing possibility for future wireless communication systems since it is a very flexible non-orthogonal waveform that can imitate various different waveforms as corner cases. This research suggests two methods for integrating SCMA with GFDM.
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Uppal, Sabhyata, Sanjay Sharma, and Hardeep Singh. "Analytical Investigation on Papr Reduction in OFDM Systems Using Golay Codes." Journal of Electrical Engineering 65, no. 5 (2014): 289–93. http://dx.doi.org/10.2478/jee-2014-0046.
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Abstract Orthogonal frequency division multiplexing (OFDM) is a common technique in multi carrier communications. One of the major issues in developing OFDM is the high peak to average power ratio (PAPR). Golay sequences have been introduced to construct 16-QAM and 256-QAM (quadrature amplitude modulation) code for the orthogonal frequency division multiplexing (OFDM), reducing the peak-to-average power ratio. In this paper we have considered the use of coding to reduce the peakto- average power ratio (PAPR) for orthogonal frequency division multiplexing (OFDM) systems. By using QPSK Golay sequences, 16 and 256 QAM sequences with low PAPR are generated
9
Lowery, Arthur James. "Spectrally efficient optical orthogonal frequency division multiplexing." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 378, no. 2169 (2020): 20190180. http://dx.doi.org/10.1098/rsta.2019.0180.
Full textAbstract:
This paper charts the development of spectrally efficient forms of optical orthogonal frequency division multiplexing (OFDM) that are suited for intensity-modulated direct detection systems, such as wireless optical communications. The journey begins with systems using a DC-bias to ensure that no parts of the signal that modulates the optical source are negative in value, as negative optical intensity is unphysical. As the DC-part of the optical signal carries no information, it is wasteful in energy; thus asymmetrically clipped optical OFDM was developed, removing any negative-going peaks below the mean. Unfortunately, the clipping causes second-order distortion and intermodulation, so some subcarriers appear to be unusable, halving spectral efficiency; this is similar for unipolar and flipped optical OFDM. Thus, a considerable effort has been made to regain spectral efficiency, using layered techniques where the clipping distortion is mostly cancelled at the receiver, from a knowledge of one unpolluted layer, enabling one or more extra ‘layers/paths/depths’ to be received on the previously unusable subcarriers. Importantly, for a given optical power and high-order modulation, layered methods offer the best spectral efficiencies and need the lowest signal-to-noise ratios, especially if diversity combining is used. Thus, they could be important for high-bandwidth optical fibre systems. Efficient methods of generating all layers simultaneously, using fast Fourier transforms with their partial calculations extracted, are discussed, as are experimental demonstrations in both wireless and short-haul communications links. A musical analogy is also provided, which may point to how orchestral and rock music is deciphered in the brain. This article is part of the theme issue ‘Optical wireless communication’.
10
Yang, Jieying. "Orthogonal frequency division multiplexing technology based on MATLAB." Applied and Computational Engineering 6, no. 1 (2023): 351–58. http://dx.doi.org/10.54254/2755-2721/6/20230807.
Full textAbstract:
The subcarriers of an orthogonal frequency division multiplexing (OFDM) system are not identical in the time domain, and their spectra also overlap. As a result, the spectrum is being used effectively. Its effective use of frequency resources and capacity to combat channel fading have made it the de facto technical standard. In wireless communication, numerous pathways in the channel can lead to interference between symbols, known as inter-symbol interference (ISI). This research supplements OFDM systems with some safeguards to eliminate inter-symbol interference. Most traditionally, OFDM symbols have had their post-event sample points duplicated to their beginnings, a process known as Cyclic prefix (CP) padding in the protection interval. In order to further counteract ISI, a protection interval might be added to the beginning of each symbol. An OFDM system's bit error rate (BER) can be decreased by using cyclic prefixes to attenuate inter-code interference. This study explains how OFDM and CP-OFDM work and compares their performance. The primary topic of this study is a contrast between OFDM and CP-OFDM concerning the performance metrics of average symbol error rate (BER) and signal spectrum diagram (PSD).