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Journal articles on the topic 'Carrier-subcarrier'

Author: Grafiati

Published: 4 June 2021

Last updated: 10 February 2022

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1

Uddin, Jia, Mohammed Faisal, Md Facihul Azam, and A. F. M. Muzahidur Rahman. "Performance Analysis of Multicarrier Code Division Multiple Access over Rayleigh Fading Channel." Advanced Materials Research 457-458 (January 2012): 985–88. http://dx.doi.org/10.4028/www.scientific.net/amr.457-458.985.

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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.

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2

Harianto, BB. "Pengukuran Kinerja Orthogonal Frekwency Division Multiplexing (OFDM) Pada Sbx Doughter Board Menggunakan Labview dan USRP N-210." Jurnal Penelitian 4, no. 1 (May 21, 2019): 64–69. http://dx.doi.org/10.46491/jp.v4e1.288.64-69.

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Salah satu permasalahan dalam perkembangan teknologi telekomunikasi yaitu bagaimana mencapai data rate yang besar namun dengan bandwidth yang tidak lebih besar dari bandwidth koheren kanal untuk menghindari terjadinya Inter-Symbol Interference (ISI). Salah satu solusi yang ditawarkan yaitu transmisi multi-carrier. Cara kerja transmisi multi-carrier yaitu membagi total bandwidth signal yang tersedia menjadi beberapa subcarrier-subcarrier dengan bandwidth yang sempit. Sehingga bandwith masingmasing subcarrier yang dihasilkan tersebut menjadi lebih kecil jika dibandingkan dengan bandwidth koheren kanal. Salah satu transmisi multicarrier yang terbaru yaitu Orthogonal Frequency Division Multiplexing (OFDM) dimana subcarrier-subcarrier dapat saling tegak lurus satu sama lain sehingga bendwidth yang dibutuhkan menjadi lebih efisien jika dibandingkan dengan multicarrier konvensional seperti FDM. Sistem OFDM dapat diimplementasikan pada USRP yang merupakan salah satu jenis SDR (Software Defined Radio). SDR merupakan sistem pemancar dan penerima yang menggunakan pemrosesan sinyal digital untuk coding, decoding, modulasi dan demodulasi data. USRP tersebut digunakan sebagai model pemancar dan penerima pada pengukuran kualitas unjuk kerja sistem OFDM dengan barbagai kondisi. Pengukuran ini akan membandingkan hasil performansi parameter – parameter pada frekwensi 910 MHz dan 2.4 GHz. Spesifikasi sistem OFDM yang digunakan pada penelitian ini menggunakan software Labview dan dilakukan pada lingkungan indoor pada jarak 3m dan bandwidth 1 MHz. Hasil dari implementasi dan pengukuran menunjukkan bahwa parameter yang ditunjukkan oleh frekwensi 910 MHz lebih baik dari pada nilai parameter yang ditunjukkan oleh frekwensi 2.4

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3

Almisbah, Nasir Salh, and Elessaid S. Saad. "Analysis of Intercarrier Interference Cancellation Scheme in OFDM Systems." Computer Engineering and Applications Journal 1, no. 1 (June 26, 2012): 13–23. http://dx.doi.org/10.18495/comengapp.v1i1.2.

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Abstract: Orthogonal Frequency Division Multiplexing (OFDM) is an emerging multi-carrier modulation scheme, which has been adopted for several wireless standards such as IEEE 802.11a and HiperLAN2. In OFDM systems, the performance is very sensitive to subcarrier frequency errors (offset). This paper shows the analysis and derivations of intercarrier interference (ICI) complex gain that used in self-cancellation scheme and its dependence on subcarrier frequency offset. Simulation shows that better improvement in performance is achieved for systems that use this cancellation scheme. Moreover, analysis and simulation show that theoretical carrier-to-interference ratio (CIR) for OFDM with cancellation scheme is greater than conventional one by more than 14dB.DOI:Â 10.18495/comengapp.11.013023

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4

Bilal, S. M., C. Fludger, and G. Bosco. "Carrier Phase Estimation in Multi-Subcarrier Coherent Optical Systems." IEEE Photonics Technology Letters 28, no. 19 (October 1, 2016): 2090–93. http://dx.doi.org/10.1109/lpt.2016.2585500.

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5

Cho, Jeong-Sik, and Yong-Hyub Won. "Optical labeling using carrier suppressed second harmonic subcarrier label." Microwave and Optical Technology Letters 49, no. 6 (2007): 1468–70. http://dx.doi.org/10.1002/mop.22418.

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6

Seyman, Muhammet Nuri, and Bircan Saçakli. "A Novel Subcarrier Allocation Algorithm for MC–CDMA Systems." Journal of Electrical Engineering 67, no. 5 (September 1, 2016): 371–76. http://dx.doi.org/10.1515/jee-2016-0053.

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Abstract Multi carrier modulation techniques such as MC-CDMA are used in high-speed communication applications. Due to MC-CDMA being a multiuser in technology, the subcarrier quantity allocated per user decreases in case the quantity of active users increases. Consequently, data rates per user are reduced with the increase in the bit error rate (BER). Efficient allocation of subcarriers to users within the system can aid the overcoming of this problem. This study develops a new algorithm for subcarrier allocation and system performance improvement in terms of BER, and data rates in comparison to other algorithms were ensured.

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7

Wang, Jia Jia, Cheng Mei Li, Bin Li, Hao Chang, and Jian Jun Wu. "Joint Selection of OFDM Parameters in Mobile Satellite Communications." Applied Mechanics and Materials 385-386 (August 2013): 1586–90. http://dx.doi.org/10.4028/www.scientific.net/amm.385-386.1586.

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In mobile satellite communication based on OFDM technology, the system performance can’t be optimal if the cyclic prefix (CP) length and subcarrier interval of LTE specification are transplanted into mobile satellite communication directly. In this paper, we analyze the impact of inter symbol interference (ISI) and inter carrier interference (ICI) which are caused by multipath delay spread and Doppler frequency shift separately on system capacity, and derive the optimal CP length and subcarrier interval for GEO, MEO and LEO mobile satellite communication by numeric calculation. Finally, the simulation results show that the OFDM parameters of LTE specification can be used in GEO mobile satellite communications, but cannot in MEO and LEO.

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8

Zhang, Jianfeng, Nan Chi, P. V. Holm-Nielsen, C. Peucheret, and P. Jeppesen. "Method for optical subcarrier label generation using carrier suppression technique." Electronics Letters 39, no. 4 (2003): 388. http://dx.doi.org/10.1049/el:20030265.

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9

Maraqa, Omar, Umair F. Siddiqi, Saad Al-Ahmadi, and Sadiq M. Sait. "On the Achievable Max-Min User Rates in Multi-Carrier Centralized NOMA-VLC Networks." Sensors 21, no. 11 (May 26, 2021): 3705. http://dx.doi.org/10.3390/s21113705.

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Visible light communications (VLC) is gaining interest as one of the enablers of short-distance, high-data-rate applications, in future beyond 5G networks. Moreover, non-orthogonal multiple-access (NOMA)-enabled schemes have recently emerged as a promising multiple-access scheme for these networks that would allow realization of the target spectral efficiency and user fairness requirements. The integration of NOMA in the widely adopted orthogonal frequency-division multiplexing (OFDM)-based VLC networks would require an optimal resource allocation for the pair or the cluster of users sharing the same subcarrier(s). In this paper, the max-min rate of a multi-cell indoor centralized VLC network is maximized through optimizing user pairing, subcarrier allocation, and power allocation. The joint complex optimization problem is tackled using a low-complexity solution. At first, the user pairing is assumed to follow the divide-and-next-largest-difference user-pairing algorithm (D-NLUPA) that can ensure fairness among the different clusters. Then, subcarrier allocation and power allocation are solved iteratively through both the Simulated Annealing (SA) meta-heuristic algorithm and the bisection method. The obtained results quantify the achievable max-min user rates for the different relevant variants of NOMA-enabled schemes and shed new light on both the performance and design of multi-user multi-carrier NOMA-enabled centralized VLC networks.

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10

Langowski, Adrian. "Carrier and Sampling Frequency Offset Estimation and Tracking in OFDM Systems." Journal of Communications Software and Systems 5, no. 2 (June 22, 2009): 62. http://dx.doi.org/10.24138/jcomss.v5i2.206.

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In This paper presents the proposition of the tracking algorithm of the carrier frequency and sampling frequency offsets. The algorithm uses a phase difference between channel transfer function estimates computed for the same subcarrier of two successive OFDM symbols. Proposed solution was compared, by means of computer simulation, with similar non-data aided algorithm introduced in [1]. Both schemes were tested by transmitting OFDM symbols over the Rayleigh fading channel.

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11

Liu, Lanjun, Hao Zhao, Ming Li, Lin Zhou, Jiucai Jin, Jie Zhang, Zhichao Lv, Hui Ren, and Jicun Mao. "Modelling and Simulation of Pseudo-Noise Sequence-Based Underwater Acoustic OSDM Communication System." Applied Sciences 9, no. 10 (May 19, 2019): 2063. http://dx.doi.org/10.3390/app9102063.

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Orthogonal signal division multiplex (OSDM) is an emerging signal modulation technology which has a lower peak-to-average power ratio (PAPR) and a flexible subcarrier system architecture. Particularly, it can be seen as a bridge between the single-carrier modulation and the orthogonal frequency division multiplexing (OFDM) modulation in the frequency domain. Aiming at the development trend and demand of underwater acoustic hybrid and adaptive modulation communication technology, a pseudo-noise (PN) sequence-based underwater acoustic OSDM communication system is proposed in this paper. A data frame structure with PN sequence is designed to solve the multipath and Doppler effect of underwater acoustic channel. On the basis of the PN sequence, a compressive sensing method based on the orthogonal matching pursuit (OMP) algorithm and the minimum mean square error (MMSE) algorithm is designed for channel estimation and equalization. On the basis of the system construction, the relationship among the OSDM vector length M, the OSDM subcarrier number N, and the underwater acoustic channel length is further studied for adaptive modulation of underwater acoustic communication. Finally, the proposed system is verified by simulation. The OSDM system has lower and controllable PAPR. When the OSDM vector length M is bigger than the channel length, and the system subcarrier flexibility is guaranteed, the bit error rate (BER) of the OSDM system is lower than that of the OFDM system and the single-carrier system. The PN sequence-based compressive sensing channel estimation and equalization with the OMP and MMSE algorithms has a good performance to resist the multipath effect of underwater acoustic channel.

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12

Pattanayak, Prabina. "Subcarrier Wise Scheduling Methods for Multi-antenna and Multi-carrier Systems." Wireless Personal Communications 114, no. 2 (May 13, 2020): 1485–500. http://dx.doi.org/10.1007/s11277-020-07434-8.

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13

Xu, Xiao Rong, Jian Wu Zhang, Bao Yu Zheng, and Jun Rong Yan. "An Efficient Subcarrier Power Allocation Algorithm in Cognitive WSN." Advanced Materials Research 255-260 (May 2011): 2062–66. http://dx.doi.org/10.4028/www.scientific.net/amr.255-260.2062.

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In Cognitive Wireless Sensor Network (C-WSN), spectrum utilization and energy-efficiency are both significant items for the whole network. Interference between Primary User (PU) sensor and Secondary User (SU) sensor should be eliminated in order to realize spectrum sharing. In this paper, mathematical model of multi-carrier power allocation in cognitive OFDM is constructed. Multi-carrier power allocation based on rate adaptive criterion is proposed under the constraints of SUs’ power control. An efficient subcarrier power allocation algorithm based on adaptive water-filling is proposed. The improved algorithm could directly determine the sub-carriers that do not require additional power injection by rough estimation of water levels. Computational complexity of proposed algorithm could reduce rapidly. Meanwhile, theoretical derivation and numerical results both indicate that, with the proposed power allocation algorithm, SU’s spectral efficiency is superior to other traditional water-filling schemes, and the algorithm also has some adaptive features for practical implementation in C-WSN.

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14

Chi, N., and Siyuan Yu. "Optical subcarrier labeling transparent to the payload format using carrier suppression technique." IEEE Photonics Technology Letters 18, no. 8 (April 2006): 971–73. http://dx.doi.org/10.1109/lpt.2006.873558.

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15

Yang, Yifei, Shuowen Zhang, Joni Polili Lie, and Rui Zhang. "Flexible Multi-Group Single-Carrier Modulation: Subcarrier Mapping and Power Allocation Optimization." IEEE Transactions on Communications 67, no. 3 (March 2019): 2002–14. http://dx.doi.org/10.1109/tcomm.2018.2883744.

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16

Kitayama, K. "Carrier sense using subcarrier-multiplexed signaling for optical frequency division multiple access." Journal of Lightwave Technology 15, no. 5 (May 1997): 758–65. http://dx.doi.org/10.1109/50.580809.

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17

Chi, N., Jianfeng Zhang, and P. Jeppesen. "All-optical subcarrier labeling based on the carrier suppression of the payload." IEEE Photonics Technology Letters 15, no. 5 (May 2003): 781–83. http://dx.doi.org/10.1109/lpt.2003.810260.

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18

Meylani, Linda, Adit Kurniawan, and M. Sigit Arifianto. "Radio Resource Allocation with The Fairness Metric for Low Density Signature OFDM in Underlay Cognitive Radio Networks." Sensors 19, no. 8 (April 23, 2019): 1921. http://dx.doi.org/10.3390/s19081921.

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Low density signature orthogonal frequency division multiplexing (LDS-OFDM), one type of non-orthogonal multiple access (NOMA), is a special case of multi-carrier code division multiple access (MC-CDMA). In LDS-OFDM, each user is allowed to spread its symbols in a small set of subcarriers, and there is only a small group of users that are permitted to share the same subcarrier. In this paper, we study the resource allocation for LDS-OFDM as the multiple access model in cognitive radio networks. In our scheme, SUs are allocated to certain d v subcarriers based on minimum interference or higher SINR in each subcarrier. To overcome the problem where SUs were allocated less than the d v subcarriers, we propose interference limit-based resource allocation with the fairness metric (ILRA-FM). Simulation results show that, compared to the ILRA algorithm, the ILRA-FM algorithm has a lower outage probability and higher fairness metric value and also a higher throughput fairness index.

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19

Ibrahim, Nur Farahiah, Zahari Abu Bakar, and Azlina Idris. "Improving Space-Time-Frequency MIMO-OFDM with ICI Self-Cancellation Scheme using Least Square Error Estimator." Scientific Research Journal 12, no. 1 (June 1, 2015): 25. http://dx.doi.org/10.24191/srj.v12i1.5436.

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Channel estimation techniques for Multiple-input Multiple-output Orthogonal Frequency Division Multiplexing (MIMO-OFDM) based on comb type pilot arrangement with least-square error (LSE) estimator was investigated with space-time-frequency (STF) diversity implementation. The frequency offset in OFDM effected its performance. This was mitigated with the implementation of the presented inter-carrier interference self-cancellation (ICI-SC) techniques and different space-time subcarrier mapping. STF block coding in the system exploits the spatial, temporal and frequency diversity to improve performance. Estimated channel was fed into a decoder which combined the STF decoding together with the estimated channel coefficients using LSE estimator for equalization. The performance of the system was compared by measuring the symbol error rate with a PSK-16 and PSK-32. The results show that subcarrier mapping together with ICI-SC were able to increase the system performance. Introduction of channel estimation was also able to estimate the channel coefficient at only 5dB difference with a perfectly known channel.

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20

Cui, Yansong, Di Zhu, and Yanxu Liu. "PRG: A Distance Measurement Algorithm Based on Phase Regeneration." Sensors 18, no. 8 (August 8, 2018): 2595. http://dx.doi.org/10.3390/s18082595.

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With the booming development of the Internet of things (IoT) industry, the demand of positioning technology in various IoT application scenarios is also greatly increased. To meet the positioning requirements of the IoT application, we propose a distance measurement method based on phase regeneration that can provide positioning capability for IoT applications in indoor and outdoor environments. The PRG algorithm consists of two phases: coarse ranging phase and fine ranging phase. Fingerprint positioning algorithm based on Gradient Boost Decision Tree (GBDT) is used to determine coarse distance. The host machine measures the difference between the transmitted carrier phase and the received regenerative carrier phase to fix the fine distance and then the coarse distance is used to determine the carrier phase integer ambiguity. Finally, high precision ranging is realized. Simulation results show that the PRG method can achieve range finding with decimeter level precision under the 10 MHz subcarrier frequency.

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21

Hara, Shinsuke, and Montree Budsabathon. "Spread Spectrum-Based Subcarrier Recovery Method for Multi-Carrier Code Division Multiplexing System." European Transactions on Telecommunications 10, no. 4 (July 1999): 369–76. http://dx.doi.org/10.1002/ett.4460100406.

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22

Qasim, Abdullah A., M. F. L. Abdullah, Rahmat Bin Talib, Mohammed N. Nemah, and Ahmed T. Hammoodi. "Low complexity DCO-FBMC visible light communication system." International Journal of Electrical and Computer Engineering (IJECE) 10, no. 1 (February 1, 2020): 928. http://dx.doi.org/10.11591/ijece.v10i1.pp928-934.

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Filter Bank Multicarrier (FBMC) is a new waveform candidate in the visible light communication system (VLC). FBMC is a distinctive kind of multi-carrier modulation that can be regarded as an alternative to orthogonal frequency Division Multicarrier (OFDM) with CP (cyclic prefix). DCO-FBMC (DC-bias optical FBMC) has recently been used in VLC, because it overcomes all defects in the optical-OFDM system and has high spectral efficiency. but at the same time the traditional DCO-FBMC suffers from high complexity due to the use of Hermitian Symmetry for real signal, by using 2N-point subcarrier IFFT (Inverse Fast Fourier Transformer) in the modulator, and the output is N-point subcarrier FFT (Fast Fourier Transform) in the demodulator. In this paper, for the first time, the possibility of minimizing complexity and generating a real signal without the use of Hermitian Symmetry or any other technique has been verified. The proposed technology provides 50% of the size of the IFFT / FFT and this results in a significant reduction in power consumption and occupied chip area.

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23

Zeng, Yu, and Hongwei Ding. "A Physical-Layer UHF RFID Tag Collision Resolution Based on Miller Code." Wireless Communications and Mobile Computing 2021 (April 28, 2021): 1–11. http://dx.doi.org/10.1155/2021/6636846.

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In an ultrahigh frequency (UHF) radio frequency identification (RFID) system, the throughput can be greatly improved by collision resolution on a physical layer when tags collide, and high-performance coding technology can improve the bit error rate (BER) performance of the physical-layer separation. Most of the traditional physical collision resolutions focus on the code with a single subcarrier. This paper pays more attention to Miller code with multiple subcarriers and proposes a novel physical-layer separation method based on the Miller code. In this method, the separated collision signals are multiplied by clock signals with the same frequency as the subcarrier to complete the frequency shift. And then, a coherent demodulation and a low-pass filter are used to remove high-frequency separation noise. In the simulation, the Miller code with more subcarriers has lower BER than FM0 code with a single carrier. Especially when Miller 8 is selected, the separation efficiency and BER performance of the proposed method are 4 dB higher than those of the traditional XOR method at lower SNR.

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24

Vahidnia, Reza, and Shahram Shahbazpanahi. "Multi-Carrier Asynchronous Bi-Directional Relay Networks: Joint Subcarrier Power Allocation and Network Beamforming." IEEE Transactions on Wireless Communications 12, no. 8 (August 2013): 3796–812. http://dx.doi.org/10.1109/twc.2013.071113.121109.

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25

Khalid, Lamiaa, and Alagan Anpalagan. "Carrier Frequency Offset in VSF-OFCDM Systems with Subcarrier Grouping: Analysis, Estimation and Correction." Wireless Personal Communications 59, no. 4 (February 16, 2010): 643–66. http://dx.doi.org/10.1007/s11277-010-9930-x.

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26

Dobroiu, Adrian, Yusuke Shirakawa, Safumi Suzuki, Masahiro Asada, and Hiroshi Ito. "Subcarrier Frequency-Modulated Continuous-Wave Radar in the Terahertz Range Based on a Resonant-Tunneling-Diode Oscillator." Sensors 20, no. 23 (November 30, 2020): 6848. http://dx.doi.org/10.3390/s20236848.

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We introduce a new principle for distance measurement in the terahertz-wave range using a resonant-tunneling-diode (RTD) oscillator as a source at 511 GHz and relying on the frequency-modulated continuous-wave (FMCW) radar technique. Unlike the usual FMCW radar, where the sawtooth frequency modulation is applied to the carrier, we propose applying it to a subcarrier obtained by amplitude modulation; this is advantageous when the source cannot be controlled precisely in oscillation frequency, but can easily be modulated in amplitude, as is the case of the RTD oscillator. The detailed principle and a series of proof-of-concept experimental results are presented.

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27

Hong, Yi, Arthur J. Lowery, and Emanuele Viterbo. "Sensitivity improvement and carrier power reduction in direct-detection optical OFDM systems by subcarrier pairing." Optics Express 20, no. 2 (January 11, 2012): 1635. http://dx.doi.org/10.1364/oe.20.001635.

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28

Hai Lin and Katsumi Yamashita. "Subcarrier allocation based compensation for carrier frequency offset and I/Q imbalances in OFDM systems." IEEE Transactions on Wireless Communications 8, no. 1 (January 2009): 18–23. http://dx.doi.org/10.1109/t-wc.2009.071007.

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29

Han, Dong-Jun, Jaekyun Moon, Dongjae Kim, Sae-Young Chung, and Yong H. Lee. "Combined Subband-Subcarrier Spectral Shaping in Multi-Carrier Modulation Under the Excess Frame Length Constraint." IEEE Journal on Selected Areas in Communications 35, no. 6 (June 2017): 1339–52. http://dx.doi.org/10.1109/jsac.2017.2687378.

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30

MotaghianNezam, S. M., J. E. McGeehan, and A. E. Willner. "Degree-of-Polarization-Based PMD Monitoring for Subcarrier-Multiplexed Signals Via Equalized Carrier/Sideband Filtering." Journal of Lightwave Technology 22, no. 4 (April 2004): 1078–85. http://dx.doi.org/10.1109/jlt.2004.825242.

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31

Neves, Manuel S., Paulo P. Monteiro, and Fernando P. Guiomar. "Enhanced Phase Estimation for Long-Haul Multi-Carrier Systems Using a Dual-Reference Subcarrier Approach." Journal of Lightwave Technology 39, no. 9 (May 1, 2021): 2714–24. http://dx.doi.org/10.1109/jlt.2021.3057680.

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32

NOOR, Litifa, Alagan ANPALAGAN, and Sithamparanathan KANDEEPAN. "Subcarrier Availability in Downlink OFDM Systems with Imperfect Carrier Synchronization in Deep Fading Noisy Doppler Channels." International Journal of Communications, Network and System Sciences 02, no. 08 (2009): 775–85. http://dx.doi.org/10.4236/ijcns.2009.28090.

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33

LI, Juhu, Huang Jing, and Nie Juan. "Performance of OFDM AF relay system with subcarrier mapping in the presence of carrier frequency offsets." Journal of China Universities of Posts and Telecommunications 22, no. 4 (August 2015): 42–50. http://dx.doi.org/10.1016/s1005-8885(15)60666-5.

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34

Capmany, J., E. Peral, and D. Pastor. "Formula for two-carrier intermodulation distortion in wavelength converted subcarrier multiplexed signals via cross gain modulation." IEEE Photonics Technology Letters 12, no. 3 (March 2000): 278–80. http://dx.doi.org/10.1109/68.826913.

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35

Yan Wu, S. Attallah, and J. W. M. Bergmans. "On the Optimality of the Null Subcarrier Placement for Blind Carrier Offset Estimation in OFDM Systems." IEEE Transactions on Vehicular Technology 58, no. 4 (May 2009): 2109–15. http://dx.doi.org/10.1109/tvt.2008.2005574.

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36

Kim, J., and H. G. Ryu. "Inter-subcarrier interference compensation in the frequency-hopped single-carrier frequency division multiple access communication system." IET Communications 4, no. 12 (2010): 1443. http://dx.doi.org/10.1049/iet-com.2009.0542.

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37

Chow, C. W., G. Talli, A. D. Ellis, and P. D. Townsend. "Rayleigh noise mitigation in DWDM LR-PONs using carrier suppressed subcarrier-amplitude modulated phase shift keying." Optics Express 16, no. 3 (2008): 1860. http://dx.doi.org/10.1364/oe.16.001860.

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38

Qian, Bo, Guolei Zheng, and Yongxin Feng. "A Detection Algorithm for the BOC Signal Based on Quadrature Channel Correlation." Journal of Electrical and Computer Engineering 2018 (2018): 1–10. http://dx.doi.org/10.1155/2018/2436472.

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In order to solve the problem of detecting a BOC signal, which uses a long-period pseudo random sequence, an algorithm is presented based on quadrature channel correlation. The quadrature channel correlation method eliminates the autocorrelation component of the carrier wave, allowing for the extraction of the absolute autocorrelation peaks of the BOC sequence. If the same lag difference and height difference exist for the adjacent peaks, the BOC signal can be detected effectively using a statistical analysis of the multiple autocorrelation peaks. The simulation results show that the interference of the carrier wave component is eliminated and the autocorrelation peaks of the BOC sequence are obtained effectively without demodulation. The BOC signal can be detected effectively when the SNR is greater than −12 dB. The detection ability can be improved further by increasing the number of sampling points. The higher the ratio of the square wave subcarrier speed to the pseudo random sequence speed is, the greater the detection ability is with a lower SNR. The algorithm presented in this paper is superior to the algorithm based on the spectral correlation.

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39

Gao, Jing Peng, Chao Qun Wu, and Dan Feng Zhao. "Time and Frequency Synchronization for MIMO-OFDM Systems." Applied Mechanics and Materials 321-324 (June 2013): 2888–91. http://dx.doi.org/10.4028/www.scientific.net/amm.321-324.2888.

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Any carrier frequency offset will cause a loss of subcarrier orthogonality which results in ICI and hence performance degrades severely in MIMO-OFDM systems. In this paper, a time and frequency synchronization solution for multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems is proposed. The synchronization is achieved using one Constant Amplitude Zero Auto Correlation (CAZAC) sequence-based preamble which is simultaneously transmitted from all transmit antennas in the same OFDM time instant. The synchronization is accomplished sequentially by coarse time synchronization, fractional frequency offset estimation, integral frequency offset estimation and fine time synchronization. The simulation shows that the proposed algorithm can estimate the timing and frequency offsets efficiently in MIMO-OFDM systems, especially in low signal-to-noise ratio condition.

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40

Al-kamali, F. S., Hefdhallah Sakran, and N. A. Odhah. "I/Q Imbalance Problem in SC-FDMA System with DCT and DFT Basis Functions." Advances in Electrical Engineering 2015 (January 29, 2015): 1–7. http://dx.doi.org/10.1155/2015/723805.

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In-phase/quadrature-phase (I/Q) imbalance is one of the most serious concerns in the practical implementation of the direct conversion receiver architecture. This paper investigates and analyzes the impacts of the I/Q imbalance on the performance of the single-carrier frequency-division multiple access (SC-FDMA) system with different basis functions by computer simulations only. The suitable phase and amplitude of I and Q branches that can be utilized in SC-FDMA system are studied and determined through simulations for different I/Q imbalance scenarios and different subcarrier mapping schemes. Simulation results show that the phase and amplitude of I and Q branches have significant effects on the bit error rate (BER) performance of the SC-FDMA system.

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YANG, TAO, and LEON O. CHUA. "CHAOTIC IMPULSE RADIO: A NOVEL CHAOTIC SECURE COMMUNICATION SYSTEM." International Journal of Bifurcation and Chaos 10, no. 02 (February 2000): 345–57. http://dx.doi.org/10.1142/s0218127400000220.

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A chaotic impulse radio system is an ultrawide-band communication system that uses a train of very narrow baseband impulses as a carrier. In the transmitter of a chaotic impulse radio system, a message signal is modulated by two kinds of pulse carriers. Firstly, a frequency modulation is used to modulate the message signal into a subcarrier that functions as the clock pulses of a chaotic circuit. Driven by the modulated clock pulses, the chaotic circuit outputs a chaotic impulse positioning sequence which generates the positions of the carrier impulses. The specially designed chaotic circuit in the transmitter guarantees that the time intervals between the carrier impulses are chaotic. Thus the energy of the impulse carrier is distributed evenly over the entire bandwidth. In the receiver of a chaotic impulse radio system the message signal is demodulated in two stages. At the first stage, the time interval between two consecutive impulses is recovered. At the second stage, a simple algorithm based on the knowledge of the chaotic circuit in the transmitter is used to calculate partially the locations of the inner clock pulses which in turn are used to demodulate the message signal. No synchronization at any level is needed in this chaotic impulse radio system. The security of this chaotic impulse radio system depends on the hardware parameters of the chaotic circuit and the inner clock pulse train. Simulation results are presented to illustrate the design procedure of an example of this chaotic impulse radio system.

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Baidas, Mohammed W., Emad Alsusa, and Khairi A. Hamdi. "Joint subcarrier assignment and weighted-sum energy-efficient power allocation in multi-carrier uplink NOMA relay networks." Physical Communication 36 (October 2019): 100821. http://dx.doi.org/10.1016/j.phycom.2019.100821.

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Won, Yong-Yuk, Dong-Hyeon Kim, Yin-Xing Piao, Soo-Jin Park, and Sang-Kook Han. "1.25-Gb/s bidirectional colorless WDM-PON based on RSOA using subcarrier detection and optical carrier suppression." Optical Fiber Technology 15, no. 2 (March 2009): 141–44. http://dx.doi.org/10.1016/j.yofte.2008.08.001.

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AliHemmati, Ruhallah, and Shahram Shahbazpanahi. "Sum-Rate Optimal Network Beamforming and Subcarrier Power Allocation for Multi-Carrier Asynchronous Two-Way Relay Networks." IEEE Transactions on Signal Processing 63, no. 15 (August 2015): 4129–43. http://dx.doi.org/10.1109/tsp.2015.2423265.

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Guerrero Gonzalez, N., D. Zibar, X. Yu, and I. Tafur Monroy. "Reconfigurable digital receiver for 8PSK subcarrier multiplexed and 16QAM single carrier phase-modulated radio over fiber links." Microwave and Optical Technology Letters 53, no. 5 (March 21, 2011): 1015–18. http://dx.doi.org/10.1002/mop.25905.

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Qiu, Meng, Qunbi Zhuge, Mathieu Chagnon, Fangyuan Zhang, and David V. Plant. "Laser Phase Noise Effects and Joint Carrier Phase Recovery in Coherent Optical Transmissions With Digital Subcarrier Multiplexing." IEEE Photonics Journal 9, no. 1 (February 2017): 1–13. http://dx.doi.org/10.1109/jphot.2016.2647221.

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Liu, Qiao Ping, Yan Ning Yang, and Wei Xia Li. "Application of OFDM Technology in 4G Mobile Network." Applied Mechanics and Materials 631-632 (September 2014): 851–55. http://dx.doi.org/10.4028/www.scientific.net/amm.631-632.851.

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OFDM (Orthogonal Frequency Division Multiplexing) is a special kind of multi-carrier digital modulation technique. Each OFDM subcarrier exists orthogonality and great use of spectrum resources. To a certain extent, the problem of shortage of spectrum resources will be eased in the future. OFDM has a good ability to resist inter symbol interference and fight against frequency selective fading, and be able to adapt to the future wireless high-speed data transmission without distortion. Each channel modulation and demodulation with FFT and IFFT is easy to implement and meet the need of the business in the wireless communication system. The paper introduces the basic principle of OFDM technology, describes the advantages of OFDM and the defects needed to be overcome. Moreover, we analyzes the characteristics of 4G technology and discusses the application of OFDM in 4G mobile network.

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Sakaue, Taichi, Chang-Jun Ahn, Tatsuya Omori, and Ken-Ya Hashimoto. "Time Domain Replica Signal Based Interference Compensation for SP-MIMO/OFDM with Large Delay Spread Channel." International Journal of Distributed Systems and Technologies 5, no. 4 (October 2014): 1–17. http://dx.doi.org/10.4018/ijdst.2014100101.

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In mobile communications, MIMO-OFDM transmission performance suffers severe degradation caused by the large delay spread channel greater than guard interval (GI). This is because the excess delay results in considerable inter-symbol interference (ISI) between adjacent symbols and inter-carrier-interference (ICI) among subcarrier in the same symbol. In case of scattered pilot (SP), the interference of pilot signals causes the deterioration of channel estimation. To mitigate this problem, in this paper, we propose the interference compensation scheme using the time domain replica signals. We make the time domain replica signals from detected signals and the excess channel impulse responses over GI. After compensation of the time domain replica signals and the received signals, we recalculate the channel state information (CSI) and the CSI is updated. Finally, we carry out the channel compensation with updated CSI for obtaining accurate compensated signals.

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Peng, Yaqiu, and Mingqi Li. "Discrete Fourier Transform-Based Block Faster-Than- Nyquist Transmission for 5G Wireless Communications." Applied Sciences 10, no. 4 (February 14, 2020): 1313. http://dx.doi.org/10.3390/app10041313.

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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.

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Tang, Yun, Feng Zheng, Hang Liu, and Tian Qi Miao. "A Data Aided Estimation Algorithm of Decimal Frequency Offset for OFDM System." Advanced Materials Research 902 (February 2014): 385–91. http://dx.doi.org/10.4028/www.scientific.net/amr.902.385.

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In recent years, orthogonal frequency division multiplexing (OFDM) technology has drawn widespread attention for its high spectral efficiency, and has doing better on combating multipath interference than traditional technology.The reason why OFDM system has high spectral efficiency is that it takes advantage of the orthogonality between sub-carriers,characteristic of which can eliminate interference of each subcarrier even when the spectrum of them overlapped.It is the demanding of orthogonality between subcarriers to demodulate signals that makes OFDM system extremely sensitive to frequency offset. Even a little frequency offset can bring inter-carrier interference.This paper studied the mechanism of formation of interference among sub-carriers, and proposed a frequency offset estimation algorithm by changing the structure of data symbols so that the data symbols can act as training sequence.The simulation results show that the proposed algorithm performs better than S.C algorithm in many aspects, such as MSE, BER, Constellation and so on.

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