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About 10,000 papers for “OFDM”

Ofdm

Tao Jiang · Encyclopedia of Wireless and Mobile Communications · 2007

Cited by 0

OFDM

Signals and communication technology · 2011

Cited by 65

OFDM

Monserrat del Río, José Francisco · RiuNet (Universitat Politècnica de València) · 2012

Cited by 0

?????? ????????? OFDM ?????? ???????????? ??????????????? ???????????? ???????????? ?????? ??????

????????? · Scholarworks@UNIST (Ulsan National Institute of Science and Technology) · 2004

????????? ??????????????? ???????????? ???????????? ????????? ?????? ????????? ????????? ?????? ?????? ????????? OFDM(Orthogonal Frequency Division Multiplexing) ??????????????? ?????? ?????? ????????? ?????? ?????? ????????? ??????????????? ??????. ??? ??????????????? ?????? ????????? OFDM ??????????????? ????????? ????????? ???????????? ?????? ?????? ????????? ????????????. ????????? ????????? ?????? ??????????????? ????????? ???????????? ?????? ?????? ??????(CSI: Channel State Information)??? ??????????????? ?????? ????????? ???????????? ??????????????? ???????????? ?????? ??????????????????. ???????????? CSI ????????? ???????????? ????????? ??? ???????????? ????????? ????????? ??? ??? ?????????, ???????????? ?????? ?????? ????????? ?????????, ?????? ?????? ?????? ????????? ???????????? QoS??? ???????????? ??? ?????? ???????????? ????????? ????????? ??????????????? ????????????. ??????????????? ????????? ????????? ?????? ?????? ?????? ????????? ???????????? ??? ?????? ??????????????? QoS??? ???????????? ??? ??????.

Cited by 0Open access

OFDM

Paulo S. R. Diniz, Wallace A. Martins, Markus V. S. Lima · Synthesis lectures on communications · 2012

Cited by 0

Comparison of DCO-OFDM, ADO-OFDM, HDC-OFDM and HNC-OFDM for Optical Wireless Communications

M. Rubaiyat Hossain Mondal · Journal of Optical Communications · 2018

Abstract This paper presents a new form of orthogonal frequency division multiplexing (OFDM) termed as hybrid noise cancelled asymmetrically clipped optical OFDM (HNC-OFDM) for optical wireless communication. This HNC-OFDM is formed by combining the concepts of noise cancelled asymmetrically clipped optical OFDM and DC biased optical OFDM (DCO-OFDM). HNC-OFDM has the same bit error rate (BER) performance and dimming flexibility but less complexity compared to the recently developed hybrid diversity combined OFDM . The optimum DC bias level for HNC-OFDM, DCO-OFDM and asymmetrically clipped DC biased optical OFDM is shown to depend on the target BER, the constellation size, the received signal to noise power ratio, the proportion of DCO-OFDM element, the link type, equalization, etc. Simulations results show that with an optimum bias, HNC-OFDM can outperform others in an average power limited channel, while DCO-OFDM is a better choice for a peak power limited channel.

Cited by 12

Introduction to OFDM and MIMO‐OFDM

2010

This chapter contains sections titled: OFDM History OFDM Schematic Channel Estimation for Multi-carrier Systems Channel Estimation for MIMO-OFDM Signal Detection in MIMO-OFDM Systems Iterative Signal Processing for SDM-OFDM System Model SDM-OFDM System Model Novel Aspects and Outline of the Book Chapter Summary

Cited by 5

Wavelet-OFDM vs. OFDM: Performance comparison

Marwa Chafii, Yahya Jasim Harbi, Alister G. Burr · 2016

Wavelet-OFDM based on the discrete wavelet transform, has received a considerable attention in the scientific community, because of certain promising characteristics. In this paper, we compare the performance of Wavelet-OFDM based on Meyer wavelet, and OFDM in terms of peak-to-average power ratio (PAPR), bit error rate (BER) for different channels and different equalizers, complexity of implementation, and power spectral density. The simulation results show that, without decreasing the bandwidth efficiency, the proposed scheme based on Meyer Wavelet-OFDM, outperforms OFDM in terms of PAPR by up to 4.5 dB, and in terms of BER by up to 6.5 dB of signal to noise ratio when using the minimum mean-square error equalizer without channel coding, at the cost of a computational complexity increase.

Cited by 24

Technology Independent Security Aware OFDM (SA-OFDM)

Monette H. Khadr, Hany Elgala, Moussa Ayyash et al. · 2019

Orthogonal frequency division multiplexing (OFDM) is currently the most prominent modulation technique, mainly due to it's spectral efficiency. To improve the security performance of OFDM based systems, multiple security approaches are proposed in literature, including physical-layer (PHY) approaches. However, these techniques are technology specific, i.e. mostly designed for radio frequency (RF) transmission and cannot be directly deployed in other technologies such as optical wireless communications (OWC). In this paper, security aware OFDM (SA-OFDM) is presented as a technology independent PHY security approach designed to suppress eavesdropping. The novelty of SA-OFDM is not only its versatility in deployment, but also in its perception in combining PHY encryption and the receiver's architecture to improve security performance. SA-OFDM is tested under additive white Gaussian noise (AWGN) and Rayleigh channel models, indicating negligible impact on system performance for both RF and OWC links. Results show that the eavesdropper becomes oblivious to the transmitted information, i.e. has a bit-error-rate (BER) of 0.5, which is equivalent to random guessing. Even if the key is seized, the eavesdropper's BER does not exceed 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> .

Cited by 0

Βασικές αρχές OFDM και διαμόρφωση OFDM/OQAM

Tsakmakidis, Georgios I. · DSpace - NTUA (National Technical University of Athens) · 2012

Ο σκοπός της διπλωματικής εργασίας ήταν η ανάλυση σε ένα βασικό επίπεδο των βασικών αρχών που διέπουν τις διαμορφώσεις OFDM και OFDM/OQAM ,καθώς και η αναφορά των προβλημάτων συστημάτων τηλεπικοινωνιών που αντιμετοπίζονται αποτελεσματικά από τις διαμορφώσεις αυτές. Τα κυριότερα από αυτά τα προβλήματα είναι η διασυμβολική παρεμβολή(ISI) και η διαφεροντική παρεμβολή(ICI). Αρχικά εξετάζεται η διαμόρφωση OFDM δίνοντας προσοχή στην ιδιότητα της ορθογωνιότητας και στο κυκλικό πρόθεμα(CP). Επίσης παρουσιάζεται παράληλλα και ένα απλοποιημένο μοντέλο συστήματος μαζί με τις αντίστοιχες μαθηματικές σχέσεις που το χαρακτηρίζουν. Στη συνέχεια εξετάζεται η διαμόρφωση OFDM/OQAM που αποτελεί εν μέρη μια γενίκευση της εφαρμογής της OFDM. Παρουσιάζεται πιο αναλυτικά το αντίστοιχο μοντέλο συστήματος μαζί με τις μαθηματικές σχέσεις που το χαρακτηρίζουν καθώς και μια πρόχειρη σύγριση των OFDM/OQAM και OFDM.

Cited by 0Open access

Single Block Index Modulation-OFDM (SBIM-OFDM)

Hany Elgala, Sławomir Stańczak · 2024

Existing frequency domain index modulation (FD-IM) schemes for orthogonal frequency division multiplexing (OFDM) are proposed to trade-off between spectral efficiency (SE), error performance (EP), and energy efficiency (EE). This paper proposes a next-generation physical layer technique to realize a more spectrally efficient FD-IM called SBIM-OFDM (single block index modulation-OFDM). All SBIM-OFDM subcarriers are active and convey the information by ordinary amplitude phase modulation (APM). The additional bits are conveyed by changing the indices of a subset of pilot subcarriers identifiable through the associated constellation shape. The achieved $2.47 \mathrm{~b} / \mathrm{s} / \mathrm{Hz}$ indicates higher SE compared with relevant FD-IM schemes (approximately 48% gain in $\mathbf{b} / \mathbf{s} / \mathbf{H z}$). Towards online deployments for Internet-ofThings (IoT) applications, this work also investigates using low-complexity machine learning (ML) based classifiers as pilot subcarrier detectors. Simulations are conducted under both optical and radio frequency (RF) channel conditions, as well as perfect and imperfect channel estimations. The simulation results indicate the potential for achieving biterror performance of $10^{-3}$ or better for optical communication channel models, with $\mathbf{9 9 \%}$ or better classification accuracy.

Cited by 0

Generalized OFDM

Myungsup Kim, Do Y. Kwak · 2017

In this paper, a generalized OFDM (G-OFDM) which protects the out of band (OOB) leakage and satisfies the orthogonality between subcarriers is proposed for next generation wireless communications. This scheme maps many data symbols to many subchannels through filter matrix, unlike the conventional OFDM that maps a data symbol to a subchannel in a one-to-one fashion. In G-OFDM, the filter matrix is used in order to limit the OOB leakage of the spectrums of input data, which is generated through processes such as jump-removing, filtering, and orthogonalizing a specially chosen initial matrix. G-OFDM is compared with OFDM in view of OOB leakage, crest factor, complementary cumulative distribution function, and bit error rate (BER) performance.

Cited by 2

Seminario OFDM

Dardari, Davide · AMS Campus - AlmaDL · 2016

Cited by 0