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İptal
Bulunan: 31 Adet 0.001 sn
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Filtreler
Filtreler
Bulunan: 31 Adet 0.001 sn
Konu Başlıkları : OFDM ✕
Koleksiyon [3]
İlgili Araştırmacılar [4]
Tam Metin [2]
Tür [4]
Yazar [13]
Alt Tür [1]
Alt Tür 1 [2]
Konu Başlıkları [20]
Açık Erişim Tarihi [1]
Tarih [7]
Tez Danışmanı [1]
Dizin Platformu [5]
İsmi Geçen [5]
WOS Kategorileri [4]
Erişime Açık

On the comparative performance analysis of turbo-coded non-ıdeal single-carrier and multi-carrier waveforms over wideband vogler-hoffmeyer hf channels

Asuman SAVAŞÇIHABEŞ

The purpose of this paper is to compare the turbo-coded Orthogonal Frequency Division Multiplexing (OFDM) and turbo-coded Single Carrier Frequency Domain Equalization (SC-FDE) systems under the effects of Carrier Frequency Offset (CFO), Symbol Timing Offset (STO) and phase noise in wide-band Vogler-Hoffmeyer HF channel model. In mobile communication systems multipath propagation occurs. Therefore channel estimation and equalization is additionally necessary. Furthermore a nonideal local oscillator generally is misaligned with the operating frequency at the receiver. This causes carrier frequen ...Daha fazlası

Makale/Derleme 2014 Radioengineering Journal 16 Görüntülenme
Erişime Açık

A novel ACO-OFDM system based on fast walsh hadamard transform

Ali ÖZEN | Büşra AVCI | Gazihan AYKIRI | Kudret KARAERİK | Elif Büşra TUNA | Sabiha YAŞAR | Hayriye SİNOP | Yusuf İslam TEK

Visible Light Communication (VLC), an alternative to radio frequency (RF), was born as a promising technology. In VLC systems, orthogonal frequency division multiplexing (OFDM) has received much attention due to its high data rate, simple equalization and robustness against inter symbol interference (ISI). However, high peak to average power ratio (PAPR) and LED non-linearity have remarkable effects on the performance of indoor VLC-OFDM systems. Asymmetrically clipped optical OFDM (ACO-OFDM) is a technique that sacrifices spectral efficiency to transmit a unipolar frequency division multiplexe ...Daha fazlası

Bildiri 2020 IEEE 2nd International Conference on Electrical, Communication and Computer Engineering, ICECCE 2020 , pp. 9 - 907 9 Görüntülenme
Erişime Açık

A novel double tree complex wavelet transform OFDM based on fast walsh hadamard transform

Ali ÖZEN | Kudret KARAERİK | Elif Büşra TUNA | Yusuf İslam TEK | Hayriye SİNOP | Sabiha YAŞAR | Büşra AVCI | Gazihan AYKIRI

In this paper, combining with the fast Walsh Hadamard transform (FWHT) to improve the performance of the double-tree complex wavelet transform (DTCWT) based OFDM technique developed to eliminate the disadvantages of the orthogonal frequency division multiplexing (OFDM) system is suggested. In order to test the achievement of the proposed DTCWT FWHT OFDM method, computer simulation studies are performed in AWGN and flat Rayleigh fading channel environments. In addition, peak to average power ratio (PAPR) simulations, which are one of the major disadvantages of the classical OFDM system, are als ...Daha fazlası

Bildiri 2020 IEEE 2nd International Conference on Electrical, Communication and Computer Engineering, ICECCE 2020 , pp. 8 - 831 9 Görüntülenme
Erişime Açık

Yeni nesil dalga formları için PAPR azaltma yöntemi PAPR reduction method for next generation waveforms

Ali ÖZEN

Günümüzde 5G ve ötesi telsiz iletişim sistemleri için hızlı, spektral verimliliği yüksek, maliyeti düşük ve çok taşıyıcılı sistemlerin dezavantajlarının daha az olduğu yeni dalga formu arayışı devam etmektedir. Bu bildiride, 5G ve ötesi için literatürde önerilen alternatif dalga formları üzerinde tepe ortalama güç oranı (peak to average power ratio, PAPR) performansını iyileştirmek için genlik kırpma yöntemi incelenmektedir. İncelenen yöntem, alternatif dalga formları ile genlik kırpma tekniğinin birleşiminden oluşmaktadır. Bu yöntem yeni nesil dalga formları üzerinde ilk defa denenmiştir. Bu ...Daha fazlası

Bildiri 2020 28th Signal Processing and Communications Applications Conference (SIU) 12 Görüntülenme
Erişime Açık

A New waveform design based on sequentially connected ILWT and FWHT transforms

Ali ÖZEN

In this study, zero tail inverse Lifting wavelet transform spread fast Walsh Hadamard transformed OFDM (ZT-ILWTs FWHT OFDM) is recommended as an alternative to the OFDM waveform for the new generation of wireless transmission systems. The recommended waveform is composed of a combination of inverse Lifting wavelet transform (ILWT) and fast Walsh Hadamard transform (FWHT) with OFDM waveform. The proposed waveform is tested with computer simulation studies for bit error rate (BER), peak to average power ratio (PAPR) and out of band emission (OOBE) performance criteria. From the attained results, ...Daha fazlası

Bildiri 2020 43rd International Conference on Telecommunications and Signal Processing (TSP) 8 Görüntülenme
Erişime Açık

A new PAPR and BER enhancement technique based on lifting wavelet transform and selected mapping method for the next generation waveforms

Asuman SAVAŞÇIHABEŞ | Ali ÖZEN

Orthogonal frequency division multiplexing (OFDM) is widely used in many digital communication systems because of its immunity to inter-symbol interference, high spectral efficiency and capability of handling multipath. Walsh-Hadamard transform (WHT) and discrete wavelet transform (DWT) have also been suggested in order to enhance the performances of multi-carrier wireless communication systems. In general, high peak-to-average power ratio (PAPR) is one of the biggest disadvantages of these systems and OFDM also has this disadvantage. Many techniques such as amplitude clipping and filtering, e ...Daha fazlası

Makale/Derleme 2021 AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS 7 Görüntülenme
Erişime Açık

A new fwht-cmf-dfe based approach for channel equalization in cp-free ofdm systems

Asuman SAVAŞÇIHABEŞ | Ali ÖZEN

Orthogonal frequency division multiplexing (OFDM) has been widely used in wireless communication systems due to its robustness against the frequency selectivity of fading channels. It provides optimal performance and it also meets the requirements of the next generation communication systems. Although OFDM has these advantages, its spectrum efficiency is usually degraded significantly due to the use of cyclic prefix (CP). In this paper, motivated to deal with this issue, the combined structure of Fast Walsh-Hadamard Transform (FWHT) and Time Domain Equalizer (TDE) is proposed to use in CP-free ...Daha fazlası

Makale/Derleme 2021 Iet Communications 6 Görüntülenme
Erişime Açık

A novel concatenated lwt and wht based ufmc waveform design forthe next generation wireless communication systems

Ali ÖZEN | Asuman SAVAŞÇIHABEŞ

A novel concatenated Lifting Wavelet Transform (LWT) and Walsh Hadamard Transform (WHT) with Universal Filtered MultiCarrier (UFMC) waveform is suggested as an alternative to Orthogonal Frequency Division Multiplexing (OFDM) waveformfor the next generation wireless telecommunication systems in this paper. The suggested waveform is composed of LWT andWHT with UFMC waveform. Both the elimination the disadvantages of OFDM and the improvement the achievement of UFMCwaveform, from the fifth generation waveform candidates, has been aimed with the suggested waveform. In order to verify theperformance ...Daha fazlası

Makale/Derleme 2020 IEEJ Transactions on Electrical and Electronic Engineering 17 Görüntülenme
Erişime Açık

A novel gfdm waveform design based on cascaded wht-lwt transform for the beyond 5g wireless communications

Asuman SAVAŞÇIHABEŞ | Ali ÖZEN

In this paper, a new WHT-LWT-GFDM waveform obtained by combining Walsh–Hadamard Transform (WHT), Lifting Wavelet Transform (LWT), and Generalized Frequency Division Multiplexing (GFDM) is presented for use in next-generation wireless communication systems. The proposed approach meets the requirement of 5th-generation (5G) and beyond communication schemes in terms of low latency, low peak-to-average-power ratio (PAPR), and low bit-error rate (BER). To verify the performance of the presented waveform, PAPR and BER simulation results were obtained in additive white Gaussian noise (AWGN) and flat ...Daha fazlası

Makale/Derleme 2021 Sensors 11 Görüntülenme
Erişime Açık

A comparative performance analysis of channel equalizer in ofdm system under jamming attacks

Ali ÖZEN

In this article, the accomplishment of OFDM systems under different jamming attacks is analyzed. Partial band jamming signal suppressing OFDM data packets partially and full band jamming signal suppressing all OFDM data packets are examined in this study. Computer simulation works are carried out to analyze the achievement of the OFDM system over AWGN and frequency selective Rayleigh fading channels under both jamming attacks. In addition, comparative performance analysis of different equalizer structures in frequency selective Rayleigh fading channel environment is performed. From the obtaine ...Daha fazlası

Bildiri 2021 5th Internatıonal Artificial Intelligence & Data Processing Symposium, Idap 2021 , pp. 1 - 7 11 Görüntülenme
Erişime Açık

Characterization of GFDM signal with timing offset, CFO, Non-Linearity, and PN

Mehmet BİLİM

Hakemlik

Hakemlik 2021 Transactions on Emerging Telecommunications Technologies 3 Görüntülenme
Erişime Açık

Görünür ışık haberleşme sistemleri için flip ofdm sistemlerinin başarımının arttırılması Improving the performance of flip OFDM systems for visible light communication systems

Ali ÖZEN

Optik kablosuz iletişim teknolojisi, radyo frekansı iletişimi için en önemli alternatif şemalardan biridir. Flip dikgen frekans bölmeli çoğullama (Flip Orthogonal Frequency Division Multiplexing OFDM, Flip-OFDM), sinyalin pozitif ve negatif parçalarının mutlak değerlerini art arda iki OFDM sembolünde ileten bir iç mekan optik kablosuz iletişim türüdür. Bu bildiride, Flip-OFDM sisteminin performansının artması için hızlı Walsh Hadamard dönüşümü (Fast Walsh Hadamard Transform, FWHT) tabanlı Flip-OFDM yöntemi (FWHT Flip-OFDM) önerilmektedir. Önerilen yöntemin performansını bit hata oranı (Bit Err ...Daha fazlası

Bildiri 2020 28th Signal Processing and Communications Applications Conference (SIU) 14 Görüntülenme
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