IEEE Xplore
Wei-Ren Peng, Bo Zhang, Kai-Ming Feng, Xiaoxia Wu, Alan E. Willner, Sien Chi,
... virtual single-sideband orthogonal frequency-division multiplexing (VSSB-OFDM) system that employs a tunable frequency gap and an iterative detection technique. The VSSB-OFDM that uses no frequency gap, which is referred to as the gapless VSSB-OFDM, is proposed as a spectrally efficient format. Compared with the intensity-modulated SSB-OFDM, the gapless VSSB-OFDM saves half the electrical bandwidth (BW), and exhibits ... frequency gap between the optical carrier and the OFDM data sideband, the calculating burden of the iterative ...
Tópico(s): Advanced Fiber Laser Technologies
2009 - Institute of Electrical and Electronics Engineers | Journal of Lightwave Technology
IEEE Xplore
Qi Yang, Yan Tang, Yiran Ma, William Shieh,
Orthogonal frequency-division multiplexing (OFDM) is a multicarrier modulation format in which the data are transmitted with a set of orthogonal subcarriers. Recently, this modulation ... and polarization dispersion. However, to realize the optical OFDM at 100 Gb/s and beyond requires extremely ... In this paper, we investigate orthogonal-band-multiplexed OFDM (OBM-OFDM) as a suitable modulation and multiplexing scheme for ... spectral efficient long-haul transmission systems. The OBM-OFDM signal can be implemented in either RF domain, ...
Tópico(s): Semiconductor Lasers and Optical Devices
2009 - Institute of Electrical and Electronics Engineers | Journal of Lightwave Technology
Abbas Hasan Kattoush, Waleed A. Mahmoud Al‐Jawher, S. Nihad,
... reception, the reliability of orthogonal frequency division multiplexing (OFDM) is limited because of the time-varying nature ... guard interval decreases the spectral efficiency of the OFDM system as the corresponding amount. Recently, it was ... based on Haar-orthonormal wavelets, discrete wavelet-based OFDM (DWT-OFDM) is capable of reducing the inter symbol interference ( ... the loss in orthogonality between the carriers. DWT-OFDM can also support much higher spectrum efficiency than discrete Fourier-based OFDM (DFT-OFDM). In this paper the DFT-OFDM ...
Tópico(s): Power Line Communications and Noise
2009 - Elsevier BV | Digital Signal Processing
Ui-Kun Kwon, Dongsik Kim, Gi-Hong Im,
... input multi-output orthogonal frequency division multiplexing (MIMO-OFDM) has become a promising candidate for next generation ... However, like a single-input single-output (SISO)-OFDM, one main disadvantage of the MIMO-OFDM is the high peak-to-average power ratio ( ... propose clipped signal reconstruction methods for the MIMO-OFDMs with spatial diversity, such as space-time and ... technique called iterative amplitude reconstruction (IAR) for SISO-OFDM. It is shown that the IAR can be easily employed for the STBC-OFDM, but it cannot be directly applied to the ...
Tópico(s): Wireless Communication Networks Research
2009 - Institute of Electrical and Electronics Engineers | IEEE Transactions on Wireless Communications
Reza Mohseni, Abbas Sheikhi, Mohammad Ali Masnadi‐Shirazi,
Orthogonal frequency division multiplexing (OFDM) radar signals have been introduced for high range resolution radars. These signals have prominent properties such as favorable ambiguity function, ... systems. But the large amplitude fluctuations of the OFDM signal make it susceptible to system nonlinearities. To alleviate this problem, constant envelope OFDM (CE-OFDM) signal has been introduced which combines orthogonal frequency ... modulation. Although several works have been reported on OFDM radar signal design, there is no a systematic ...
Tópico(s): Advanced Wireless Communication Techniques
2009 - Elsevier BV | AEU - International Journal of Electronics and Communications
Ebrahim Saberinia, Jin Tang, Ahmed H. Tewfik, Keshab K. Parhi,
... of a multiband orthogonal frequency-division multiplexing (MB-OFDM) ultrawideband (UWB) system by applying ideas from pulsed ... applicable to many other systems. Unlike the MB-OFDM system, the enhancement that we propose uses pulses ... amplitude shaping pulse of orthogonal frequency-division multiplexing (OFDM) modulation. Pulsating OFDM symbols spread the spectrum of the modulated signals ... subcarriers. We study the spectral characteristics of pulsed OFDM and the added degrees of diversity that it provides. We show that pulsed-OFDM signals can easily be generated by either upsampling ...
Tópico(s): Power Line Communications and Noise
2009 - Institute of Electrical and Electronics Engineers | IEEE Transactions on Vehicular Technology
T. de Couasnon, Raoul Monnier, Jean Bernard Rault,
... QAM techniques to orthogonal frequency division and multiplexing (OFDM). Theoretical performances of OFDM are derived and extended to cross-polarisation systems. Two generations of OFDM modems are described in detail, and real measurements ... mit QAM bishin zur Orthogonal Frequency Division Multiplexing (OFDM) werden theoretische Aspekte digitaler Modulation dargestellt. Das theoretische Verhalten der OFDM wird abgeleitet und auf Kreuzpolarisationssysteme erweitert. Zwei Generationen von OFDM-Modems werden genau beschrieben, Messungen, die mit Geräten ...
Tópico(s): PAPR reduction in
1994 - Elsevier BV | Signal Processing
Steve C. Thompson, Ahsen U. Ahmed, J.G. Proakis, J.R. Zeidler, Michael J. Geile,
... to-average power ratio (PAPR) problem associated with OFDM (orthogonal frequency-division multiplexing). Constant envelope OFDM (CE-OFDM) transforms the OFDM signal, by way of phase modulation, to a ... phase demodulation - is applied prior to the conventional OFDM demodulator. The performance of CE-OFDM is analyzed in additive white Gaussian noise (AWGN) and fading channels. CE-OFDM is shown to achieve good performance in dense ... way of computer simulation and hardware realization, CE-OFDM is shown to compare favorably to conventional OFDM.
Tópico(s): Wireless Communication Networks Research
2008 - IEEE Communications Society | IEEE Transactions on Communications
The CI-OFDM (carrier interferometry orthogonal frequency division multiplexing) system has been widely studied in the multi-carrier communication system. This CI-OFDM system spreads each information symbol across all N ... carriers using orthogonal CI spreading codes. The CI-OFDM system can show the advantage of PAPR (peak ... antennas configuration, we evaluate the performance of MIMO OFDM and MIMO CI- OFDM system. SFBC (space frequency block coding) coding is applied into both MIMO OFDM system and MIMO CI-OFDM system. For CI- ...
Tópico(s): Wireless Communication Networks Research
2008 - Institute of Electrical and Electronics Engineers | IEEE Transactions on Consumer Electronics
Haijian Zhang, Didier Le Ruyet, Michel Terré,
... the licensed systems. Conventional orthogonal frequency division multiplexing (OFDM) has also been suggested as a physical layer ... In this paper, another potential candidate for CR, OFDM/offset quadrature amplitude modulation (OQAM) is introduced and compared with cyclic prefix based‐OFDM (CP‐OFDM) and raised cosine windowed‐OFDM (RC‐OFDM) in CR context, in which including spectral efficiency ... theoretic analysis and experimental results can show that OFDM/OQAM is a more natural candidate than CP‐ ...
Tópico(s): Cognitive Radio Networks and Spectrum Sensing
2008 - Wiley | Wireless Communications and Mobile Computing
William Shieh, Qi Yang, Yaoguang Ma,
Coherent optical OFDM (CO-OFDM) has emerged as an attractive modulation format for the forthcoming 100 Gb/s Ethernet. However, even the spectral-efficient implementation of CO-OFDM requires digital-to-analog converters (DAC) and analog- ... and elucidate the principle of orthogonal-band-multiplexed OFDM (OBM-OFDM) to subdivide the entire OFDM spectrum into multiple orthogonal bands. With this scheme, ... concept transmission experiment through optical realization of OBM-OFDM. To the best of our knowledge, we present ...
Tópico(s): Semiconductor Lasers and Optical Devices
2008 - Optica Publishing Group | Optics Express
... Some Multicarrier Modulation (MCM) based systems use FFT OFDM, and some use a Wavelet OFDM in place of FFT OFDM. Wavelet transforms consist of an M-band transmultiplexers, ... length than the rectangular windows used in FFT OFDM. The use of symbols of longer duration allows ... lower side-lobe levels with respect to FFT OFDM. Better stop-band attenuation results in both lower ... Physical layer) data rates [Mbps] achievable by Wavelet OFDM over Channels A and B are shown for ... the effects of ISI and ICI on Wavelet OFDM can be compensated by increasing the number of ...
Tópico(s): Telecommunications and Broadcasting Technologies
2008 - | IEEJ Transactions on Electronics Information and Systems
Syed Faisal Shah, Ahmed H. Tewfik,
... discusses the design and analysis of post coded OFDM (PC-OFDM) systems. Coded or precoded OFDM systems are generally employed to overcome the symbol recovery problem in uncoded OFDM systems. We show that PCOFDM systems are a special case of precoded OFDM systems that offer advantageous complexity-performance trade-offs. In particular, PC-OFDM systems introduce frequency diversity by manipulating the OFDM symbols in the time domain so that the ... reduced. We discuss the design principles of PC-OFDM transmitter that uses upsampling operation and the spreading ...
Tópico(s): Advanced Wireless Network Optimization
2008 - Institute of Electrical and Electronics Engineers | IEEE Transactions on Wireless Communications
Spectrally precoded orthogonal frequency-division multiplexing (OFDM) is a promising rectangularly pulsed OFDM signaling format which can provide very small power spectral sidelobes, while allowing for efficient implementation by ... general constraints on spectral precoding are developed for OFDM signals with zero padding (ZP-OFDM) or cyclic prefix (CP-OFDM) to warrant the desirable spectral property that the ... the precoder design of the spectrally precoded CP-OFDM that can provide fast decaying sidelobes. New correlative ...
Tópico(s): Coding theory and cryptography
2008 - IEEE Communications Society | IEEE Transactions on Communications
Haris Gacanin, Fumiyuki Adachi,
Orthogonal frequency division multiplexing (OFDM) is currently under intense research for broadband wireless transmission due to its robustness against multipath fading. However, OFDM signals have a problem with high peak-to- ... to have a large input power backoff. Recently, OFDM combined with time division multiplexing (OFDM/TDM) using minimum mean square error frequency domain ... the bit error rate (BER) performance of conventional OFDM while reducing the PAPR. In this paper, by ... simulation, we present a comprehensive performance comparison between OFDM/TDM using MMSE-FDE and conventional OFDM over ...
Tópico(s): Advanced Wireless Communication Techniques
2008 - Institute of Electrical and Electronics Engineers | IEEE Vehicular Technology Conference
Chenggao Han, Takeshi Hashimoto, N. Suehiro,
Although the single antenna vector OFDM (VOFDM) proposed by Xia shows performance robust to channel spectral nulls, it does not necessarily attain full diversity for multi-path ... simple application of constellation rotation to the V-OFDM system does not, however, improve its performance. In ... the sub-channel spectral structure of the V-OFDM signal and give upper bounds on its pair- ... channels and propose a novel constellation-rotated V-OFDM (CRV-OFDM) with improved diversity. To this end, we design ... BER. Simulation results show that the proposed CRV-OFDM attains diversity order min{M,P} for the ...
Tópico(s): Wireless Communication Networks Research
2010 - IEEE Communications Society | IEEE Transactions on Communications
C. Lélé, Pierre Siohan, Rodolphe Legouable,
This paper deals with the combination of OFDM/OQAM with the Alamouti scheme. After a brief presentation of the OFDM/OQAM modulation scheme, we introduce the fact that the well-known ... coding scheme requires a complex orthogonality property; whereas OFDM/OQAM only provides real orthogonality. However, as we ... some conditions, a transmission scheme combining CDMA and OFDM/OQAM can satisfy the complex orthogonality condition. Adding ... to apply the Alamouti scheme in combination with OFDM/OQAM. However, our analysis shows that the CDMA- ...
Tópico(s): Wireless Communication Networks Research
2010 - Springer Science+Business Media | EURASIP Journal on Advances in Signal Processing
... We employ a broadband orthogonal frequency division multiplexing (OFDM) signal to increase the frequency diversity of the ... average power ratio (PAPR) problem of the conventional OFDM, we also use constant-envelope OFDM (CE-OFDM) signaling scheme. First, we consider a simple scenario ... We develop parametric measurement models, for both the OFDM and CE-OFDM signaling methods, under the generalized multivariate analysis of ... algorithm to optimally design the parameters of the OFDM transmitting waveform for the next coherent processing interval. ...
Tópico(s): Radio Wave Propagation Studies
2010 - Institute of Electrical and Electronics Engineers | IEEE Transactions on Signal Processing
Daniel J. F. Barros, Joseph M. Kahn,
... discuss the use of orthogonal frequency-division multiplexing (OFDM) for combating group-velocity dispersion (GVD) effects in ... systems using single-mode fiber. We review known OFDM techniques, including asymmetrically clipped optical OFDM (ACO-OFDM), DC-clipped OFDM (DC-OFDM) and single-sideband OFDM (SSB-OFDM), and derive a linearized channel model for each ... procedure to achieve optimum power allocation for each OFDM technique, since there is no closed-form solution ... allocation among the subcarriers. We verify that SSB-OFDM has the best optical power efficiency among the ...
Tópico(s): Advanced Photonic Communication Systems
2010 - Institute of Electrical and Electronics Engineers | Journal of Lightwave Technology
Chi‐Wai Chow, Chien‐Hung Yeh, Chi‐Chuan Wang, Cheng‐En Wu, Sien Chi, Chinlon Lin,
Using orthogonal-frequency-division-multiplexing (OFDM) format for passive optical network (PON) is a subject of great interest for recent research works. OFDM signal has high spectral efficiency, high tolerance to ... In this paper we study the use of OFDM signals for optical access networks, including carrier distributed ... wired/wireless network and a 100 Gb/s OFDM-PON. We first quantify the performance of the OFDM signal when subjected to the noise produced by ... results, we also study the possibility of using OFDM for signal remodulation in a long-reach (LR)- ...
Tópico(s): Advanced Optical Network Technologies
2010 - Institute of Electrical and Electronics Engineers | IEEE Journal on Selected Areas in Communications
Toon van Waterschoot, Vincent Le Nir, Jonathan Duplicy, Marc Moonen,
... spectral density (PSD) of orthogonal frequency division multiplex (OFDM) signals employing a cyclic prefix (CP-OFDM) or zero padding (ZP-OFDM) time guard interval. Under the relatively weak assumptions ... data are independent and identically distributed on all OFDM subcarriers and (ii) the OFDM pulse shape is sufficiently localized in time, simple ... obtained. These expressions are then compared to existing OFDM PSD expressions and validated by inspecting the power spectra of some standardized OFDM signals.
Tópico(s): Advanced Wireless Communication Techniques
2010 - Institute of Electrical and Electronics Engineers | IEEE Signal Processing Letters
An Li, William Shieh, Rodney S. Tucker,
Wavelet packet transform-based optical OFDM (WPT-OFDM) systems can be used as an alternative approach to the conventional optical OFDM systems. In this paper, we investigate the performance and limitation of real WPT-OFDM systems. Its double-sideband characteristic makes it sensitive ... mode dispersion (PMD). Simulations of dual-polarization WPT-OFDM transmission are carried out in the presence of ... and compared with conventional Fourier transform-based optical OFDM (FT-OFDM). The results show that WPT-OFDM ...
Tópico(s): PAPR reduction in
2010 - Institute of Electrical and Electronics Engineers | Journal of Lightwave Technology
Spectrally precoded orthogonal frequency-division multiplexing (OFDM) and constant-envelope OFDM (CE-OFDM) are two modified OFDM formats that enhance the signaling features of OFDM, while allowing for the efficient implementation by discrete ... intervals to counteract channel dispersion. The spectrally precoded OFDM signal provides very small power spectral sidelobes decaying ... achieving higher spectral efficiency than nonprecoded rectangularly-pulsed OFDM which has power spectral sidelobes decaying asymptotically as ...
Tópico(s): Power Line Communications and Noise
2010 - IEEE Communications Society | IEEE Transactions on Communications
Daniel J. F. Barros, Joseph M. Kahn,
... of several direct-detection orthogonal frequency-division multiplexing (OFDM) schemes to that of ON-OFF keying (OOK) ... dispersion in multimode fiber links. We review known OFDM techniques, including dc-clipped OFDM (DC-OFDM), asymmetrically clipped optical OFDM (ACO-OFDM) and pulse-amplitude modulated discrete multitone (PAM-DMT). ... procedure to achieve optimal power allocation for DC-OFDM and compare analytically the performance of ACO-OFDM and PAM-DMT. We also consider unipolar M - ... DFE has a better power performance than all OFDM formats. Furthermore, we observe that the difference in ...
Tópico(s): Advanced Photonic Communication Systems
2011 - Institute of Electrical and Electronics Engineers | Journal of Lightwave Technology
Chen Chen, Qunbi Zhuge, David V. Plant,
... a new channel estimation/equalization algorithm for coherent OFDM (CO-OFDM) digital receivers, which enables the elimination of the cyclic prefix (CP) for OFDM transmission. We term this new system as the zero-guard-interval (ZGI)-CO-OFDM. ZGI-CO-OFDM employs an overlapped frequency-domain equalizer (OFDE) to ... CD) and polarization mode dispersion (PMD) before the OFDM demodulation. Despite the zero CP overhead, ZGI-CO-OFDM demonstrates a superior PMD tolerance than the previous reduced-GI (RGI)-CO-OFDM, which is verified under several different PMD conditions. ...
Tópico(s): Optical Wireless Communication Technologies
2011 - Optica Publishing Group | Optics Express
ABSTRACT Orthogonal frequency division multiplexing (OFDM) transmission equipped with multiple receive antennas constitutes a single‐input multiple‐output (SIMO) OFDM system. SIMO‐OFDM systems have been widely used in wireless communications. ... training sequences, blind channel estimation methods for SIMO‐OFDM systems have the advantage of saving bandwidth and ... padding (ZP)‐based single‐input single‐output (SISO)‐OFDM systems have desirable features compared to conventional cyclic prefix (CP)‐based SISO‐OFDM systems. However, it is yet unknown whether ZP‐ ...
Tópico(s): Wireless Communication Networks Research
2011 - Wiley | Wireless Communications and Mobile Computing