Time-Domain Equalization Technique for Intercarrier Interference Suppression in OFDM Systems

Kumar, Raghvendra; Malarvizhi, S.; Jayashri, S.

doi:10.3923/itj.2008.149.154

Cited by 12 publications

(2 citation statements)

References 6 publications

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“…In addition, the decomposition of the eigenvectors leads to the diagonalization of the channel matrix [42]. While at the receiver side, using time domain equalization techniques offers better performance compared to frequency domain [43]. The received signal in the frequency domain may be written as follows:…”

Section: Proposed Predistorter For Mimo-gfdm Systemsmentioning

confidence: 99%

Nonlinear Distortion Cancellation using Predistorter in MIMO-GFDM Systems

et al. 2019

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Generalized frequency division multiplexing (GFDM) with offset quadrature amplitude modulation (OQAM) is an alternative non-orthogonal modulation scheme for future generation wireless broadband systems. The nonlinearity of high power amplifiers (HPAs) has a very significant effect on the performance of GFDM systems. In this paper, we investigate the effects of nonlinear distortion on the multiple-input multiple-output (MIMO)-GFDM system when the signal is passed the HPA, which is modeled with amplitude and phase distortion. The effects of nonlinear distortion due to the HPA include amplitude distortion, phase distortion, and the spread of signal constellations. These effects also produce harmonic signals and intermodulation outside the frequency band which results in spectral spread. This will then reduce the performance of the MIMO-GFDM system. The contributions of this paper concern three key areas. Firstly, we investigate the effects of nonlinear distortion on the MIMO-GFDM system. We also derive the new closed-form expression bit error rate (BER) in MIMO-GFDM systems that use a memoryless HPA, which is modeled using the Saleh model when passed through the additive white Gaussian noise (AWGN) channel. This model was chosen because it is simple and has AM/AM and AM/PM curves. Secondly, we propose the application of techniques for the linearization of each HPA predistorter on the transmitter side of the MIMO-GFDM system separately. This predistorter is able to compensate for nonlinear distortion caused by the HPA without memory operating in the saturation region. The main contribution of this paper is to investigate the predistorter, which can linearize nonlinear distortion in MIMO-GFDM transmitters. The performance of the proposed scheme is evaluated in terms of spectrum analysis, PAPR analysis, a constellation diagram, and bit error rate (BER) analysis. The simulation results show that the proposed predistorter design succeeds in compensating for nonlinear distortions caused by the HPA for large input back-off (IBO) values.

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Section: Proposed Predistorter For Mimo-gfdm Systemsmentioning

confidence: 99%

Nonlinear Distortion Cancellation using Predistorter in MIMO-GFDM Systems

et al. 2019

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“…Since the time variation of a wireless channel is related with the relative speed and the frequency offset at both ends, it becomes critical to reduce the negative effect with frequency-domain equalization (FDE) [2], time-domain windowing technology [3][4][5], and self-interference cancellation [6]. In Ref.…”

Section: Introductionmentioning

confidence: 99%

A method of ICI cancellation for OFDM with delay diversity

Tang

Zhang

2011

Front. Electr. Electron. Eng. China

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In orthogonal frequency division multiplexing (OFDM) system, the time variation of a wireless channel destroys orthogonality among the sub-carriers, and this induces inter-carriers interference (ICI) and degrades system performance severely in mobile environment. In this paper, a new method of ICI cancellation based on delay diversity (DD) was proposed, which provides a way to mitigate the negative effect from the time variation of the wireless paths, thus improve the system performance greatly. The new method was called time-domain selfinterference cancellation (TDSIC) algorithm, which is different from other existing methods, such as frequencydomain method. In a cyclically extended OFDM system, the fading characteristics of extended OFDM symbols with different cyclic delay are different with each other, so in our TDSIC method, a new diversity collection scheme at the receiver end is proposed, which can be used to improve the system performance by suppressing ICI through selecting appropriate parameters. Moreover, the cyclically extended OFDM symbol at the transmitter side and diversity collection with different delay added OFDM symbols at the receiver side are used in the TDSIC method with the tradeoff of time-expense, so the well-known fixed delay for symbol at the transmitter side may be detected by the receiver side through estimating several parameters of wireless channels. In summary, the key of the TDSIC method is to improve the system performance with the cost of time. Based on performance analysis, simulation has proved that TDSIC may effectively improve the performance of the time-variant wireless channel.

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ICI and PAPR enhancement in MIMO-OFDM system using RNS coding

Youssef

Emam

Elghany

2019

IOP Conf. Ser.: Mater. Sci. Eng.

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The Inter-Carrier-Interference (ICI) and the Peak-to-Average-Power Ratio (PAPR) of the transmitted signal are considered as bottlenecks in the utilization of Multiple-Input-Multiple-Output Orthogonal Frequency Division Multiplexing (MIMO-OFDM) systems, which caused a significant performance degradation. In this paper Residue Numbers as a coding scheme is impeded in MIMO-OFDM systems, where the PAPR values are analysed and compared to non-RNS coding systems, and the ICI levels are measured and evaluated with respect to the conventional ICI mitigation techniques as pulse shaping, windowing and self-cancellation techniques implemented in MIMO-OFDM system. The ICI errors, Bit-Error-Rate (BER) and the Complementary Cumulative Distribution Function (CCDF) for MIMO-OFDM system with Residue Number System (RNS) coding are analysed and evaluated. The results demonstrated a performance enhancement of the transmission model over the system without RNS implementation.

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Time-Domain Equalization Technique for Intercarrier Interference Suppression in OFDM Systems

Cited by 12 publications

References 6 publications

Nonlinear Distortion Cancellation using Predistorter in MIMO-GFDM Systems

Nonlinear Distortion Cancellation using Predistorter in MIMO-GFDM Systems

A method of ICI cancellation for OFDM with delay diversity

ICI and PAPR enhancement in MIMO-OFDM system using RNS coding

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