Browsing by Author "Doğan, Hakan"
Now showing items 1-18 of 18
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An efficient joint channel estimation and decoding algorithm for turbo-coded space-time orthogonal frequency division multiplexing receivers
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Publisher and Date:(Inst Engineering Technology-IET, 2008)The challenging problem in the design of digital receivers of today's and future high-speed high data-rate wireless communication systems is to implement the optimal decoding and channel estimation processes jointly in a computationally feasible way. Without realising such a critical function perfectly at receiver the whole system will not work properly within the desired performance limits. Unfortunately direct implementation of such optimal algorithms is not possible mainly due to their ...
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An efficient joint data detection and channel estimation technique for uplink MC-CDMA systems based on SAGE algorithm
Authors:
Publisher and Date:(IEEE, 2007)This paper is concerned with joint channel estimation and data detection for uplink multicarrier code-division multiple-access (MC-CDMA) systems in the presence of frequency fading channel. The detection and estimation algorithm implemented at the receiver is based on a version of the expectation maximization (EM) technique called the spece-alternating-generalized-expectation-maximization (SAGE) algorithm which is very suitable for the the multicarrier signal formats. Application of the SAGE ...
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Channel Estimation for Spatial Modulation Orthogonal Frequency Division Multiplexing Systems
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Publisher and Date:(IEEE, 2015)A combination of spatial modulation and orthogonal frequency division multiplexing (SM-OFDM) has been recently proposed for multicarrier systems while assuming the perfect channel state information (P-CSI) available at the receiver. But in practical scenarios the estimation of CSI is crucial in order to detect the transmitted data coherently. In this work(1) a new frame structure and pilot symbol aided channel estimation (PSA-CE) technique with a piecewise linear interpolation is proposed for the ...
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EM-based joint data detection and channel estimation for uplink MC-CDMA systems over frequency selective channels
Authors:
Publisher and Date:(IEEE, 2007)This paper is concerned with joint channel estimation and data detection for uplink multicarrier code-division multiple-access (MC-CDMA) systems in the presence of frequency fading channel. The detection and estimation algorithm implemented at the receiver is based on a version of the expectation maximization (EM) technique which is very suitable for the multicarrier signal formats. Application of the EM-based algorithm to the problem of iterative data detection and channel estimation leads to a ...
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EM-Based MAP channel estimation and data detection for downlink MCC-CDMA systems
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Publisher and Date:(IEEE, 2007)In this work we propose a joint MAP channel estimation and data detection technique based on the Expectation Maximization (EM) method with paralel interference cancelation(PIC) for downlink multi-carrier (MC) code division multiple access (CDMA) systems in the presence of frequency selective channels. The EM algorithm derived estimates the complex channel parameters of each subcarriers iteratively and generates the soft information representing the data a posterior probabilities. The soft information ...
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EM-MAP based initialization of PIC receiver for downlink MC-CDMA systems
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Publisher and Date:(IEEE, 2007)The quality of multiple access interference (MAI) which can be improved by using channel estimation and data estimation of all active users effects considerably the performance of PIC detector. Therefore data and channel estimation performance is obtained in the initial stage has a significant relationship with the performance of PIC. So obviously it is necessary to make excellent joint data and channel estimation for initialization of PIC detector. In this work to initiate PIC module efficiently ...
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Iterative channel estimation and decoding of turbo coded SFBC-OFDM systems
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Publisher and Date:(IEEE, 2007)We consider the design of turbo receiver structures for space-frequency block coded orthogonal frequency division multiplexing (SFBC-OFDM) systems in the presence of unknown frequency and time selective fading channels. The Turbo receiver structures for SFBC-OFDM systems under consideration consists of an iterative MAP Expectation/Maximization (EM) channel estimation algorithm soft MMSE-SFBC decoder and a soft MAP outer-channel-code decoder. MAP-EM employs iterative channel estimation and it ...
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Iterative channel estimation for spatial modulation systems over fast fading channels
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Publisher and Date:(IEEE, 2014)Spatial Modulation (SM) based on the use of antenna indices to transmit information in addition to the conventional signal constellations has been recently proposed to solve practical problems encountered in MIMO systems. In the literature estimation of CSI for SM systems is simply investigated by RLS for slow fading channels. However iterative receivers that offer significant performance gains over a non- iterative when the total number of pilot is not sufficient and the channel is fast fading ...
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Iterative channel estimation techniques for uplink MC-CDMA systems
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Publisher and Date:(IEEE, 2007)In this work maximum likelihood (ML) channel estimation for uplink multicarrier code-division multiple-access (MC-CDMA) systems is considered in the presence of frequency fading channel. The expectation-maximization (EM)- and a space-alternating generalized expectation-maximization (SAGE) algorithm are introduced to avoid matrix inversion for the ML channel estimation problem. We compare the both algorithms in terms of the number of used iteration and show that the proposed algorithms converge the ...
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Iterative Receiver for DS-CDMA Systems in the Presence of Time-Varying Channels
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Publisher and Date:(IEEE, 2008)In this paper we present an efficient iterative receiver structure of tractable complexity for joint multiuser detection and multichannel estimation (JDE) of direct-sequence code-division multiple-access systems operating in the presence of time-varying flat fading channel. The time-varying channel is assumed to be modeled according to a piece-wise constant channel. An optimality criterion is defined and analytical expressions for the corresponding optimized weight coefficients are given. Monte-Carlo ...
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Joint data detection and channel estimation for uplink MC-CDMA systems over frequency selective channels
Authors:
Publisher and Date:(Springer, 2007)This paper is concerned with joint channel estimation and data detection for uplink multicarrier code-division multiple-access (MC-CDMA) systems ill the presence of frequency fading channel. The detection and estimation implemented at the receiver are based on a version of the expectation maximization (EM) algorithm which is very suitable for the the multicarrier signal formats. Application of the EM-based algorithm to the problem of iterative data detection and channel estimation leads to a ...
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MAP channel-estimation-based PIC receiver for downlink MC-CDMA systems
Authors:
Publisher and Date:(Hindawi Publishing Corporation, 2008)We propose a joint MAP channel estimation and data detection technique based on the expectation maximization (EM) method with paralel interference cancelation (PIC) for downlink multicarrier (MC) code division multiple access (CDMA) systems in the presence of frequency selective channels. The quality of multiple access interference (MAI) which can be improved by using channel estimation and data estimation of all active users affects considerably the performance of PIC detector. Therefore data and ...
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On channel estimation for spatial modulated systems over time-varying channels
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Publisher and Date:(Academic Press Inc Elsevier Science, 2015)Spatial Modulation (SM) has been proposed recently for multiple-input multiple-output (MIMO) systems to cope with the interchannel interference and to reduce the detection complexity as compared to the conventional MIMO systems. In SM system the data symbols are transmitted by a randomly selected active antenna of a MIMO transmitter to the receiver through a wireless channel. The information is carried both by the data symbol from any signal constellation such as M-ary phase shift keying (M-PSK) ...
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Pilot Assisted Channel Estimation for Asymmetrically Clipped Optical OFDM over Visible Light Channels
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Publisher and Date:(IEEE, 2016)The Visible Light Communication(VLC) has drawn significant attention recently for wireless communication in addressing the performance limitations of wireless systems due to the scarcity of bandwidth. In VLC system the visible lights is used not only for illuminating rooms but also for an optical data transmission. Asymmetrically clipped optical orthogonal frequency-division multiplexing (ACO-OFDM) has been proposed for VLC systems to provide optically power efficient solution in the optical domain. ...
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Pilot Symbol Aided Channel Estimation for Spatial Modulation-OFDM Systems and its Performance Analysis with Different Types of Interpolations
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Publisher and Date:(Springer, 2017)Spatial modulation orthogonal frequency division multiplexing (SM-OFDM) system has been recently proposed as an alternative for multiple-input multiple-output (MIMO)-OFDM systems to increase spectral efficiency by keeping a low-complexity implementation. In the literature SM-OFDM systems assume a perfect channel state information (P-CSI) available at the receiver for coherent detection and the channel estimation problem is not considered. It is clear that the channel estimation is a critical issue ...
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Pilot Symbol Assisted Channel Estimation for 4x4 Space Time Block Coded Spatial Modulation Systems
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Publisher and Date:(IEEE, 2015)Recently spatial modulation (SM) and space-time block coding (STBC) are combined to take advantage of the benefits of both while avoiding their drawbacks for multiple-input and multiple-output (MIMO) systems. The pioneering works on STBC-SM assume that perfect knowledge of the channel fading coefficients is available at the receiver. This work(1) addresses the challenging and timely problem of channel estimation for 4 x 4 STBC-SM systems in the presence of time-varying channels. In this paper the ...
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Spline Based Channel Estimation for STBC-SM Systems over Fast-Varying Rician Fading Channels
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Publisher and Date:(IEEE, 2015)In the STBC-SM systems the information is carried both by STBC symbols and indices of the transmit antennas from which these symbols are transmitted. Channel estimation is a critical process at the receiver during the coherent detection of the transmitted STBC symbols and indices of the transmit antennas. In this paper a spline interpolation and pilot symbols based channel estimation has been proposed for the space-time block coded spatial modulation (STBC-SM) systems to track the channel variations ...
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Spline Interpolation Based Channel Estimation for ACO-OFDM over Visible Light Channels
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Publisher and Date:(IEEE, 2016)Visible light communication has been considered one of promising candidate technology to solve performance limitation due to bandwidth shortage at radio frequency (RF) band. In VLC system the visible light is used not only for illuminating rooms but also for an optical data transmission. ACO-OFDM is a power efficient modification of OFDM to use in VLC systems. Wireless communication systems generally require estimating and tracking the fading channel in order to detect transmitted data coherently. ...
