Efficient joint carrier offset and channel estimator for T-OFDM system

Ahmed, Mohammed Sh.; Aliesawi, Salah A.

doi:10.1109/iceccpce.2013.6998762

Cited by 4 publications

(1 citation statement)

References 14 publications

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“…In visual communications, the main objective is to obtain a high level processing speed and low computing time at the same time while not scarifying in picture quality (Ahmed and Aliesawi, 2013). Video compression has become important technology in a lot of operations in the storage or transmission, especially in the television broadcasting operations or closed conferences.…”

Section: Introductionmentioning

confidence: 99%

Block Matching of Motion Estimation by using New Technique "Quintet Search Algorithm"

Salman¹,

Mustafa²,

Gathban³

2020

J. Eng. Appl. Sci.

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In digital video communication it is not sensible and practical to store the total digital video without handling because of the many problems and constraints in the process of storage and the transmitter, so, the method of processing called a video compression. In video compression, one of the most important techniques that contribute to getting compression ratio and speed in performance is the motion estimation. The motion estimation could be a method that determines the motion between two or more frames of video. In this study we have proposed a calculation of block matching for motion estimation named (Quintet search algorithm). This algorithm it is similar in terms of work (Three step search algorithm) with eight points but the proposed algorithm is five points to get the speed and compression ratio acceptable in less time and a really acceptable PSNR compared to the other ways.

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Section: Introductionmentioning

confidence: 99%

Block Matching of Motion Estimation by using New Technique "Quintet Search Algorithm"

Salman¹,

Mustafa²,

Gathban³

2020

J. Eng. Appl. Sci.

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Performance enhancement of UWA‐OFDM communication systems based on FWHT

El-Mahallawy

Eldien

2019

Int J Communication

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The available bandwidth of underwater environment tends to several kilohertz, which considers the main challenges of communications under sea water. On the other hand, the bit-error-rate (BER) performance degrades because of several reasons such as multipath propagation, time variabilities of the channel, attenuation, and water temperature. In this paper, we aim to improve the underwater acoustic (UWA) BER system performance by using orthogonal frequency division multiplexing (OFDM) based on fast Walsh-Hadamard transform (FWHT) instead off fast Fourier transform (FFT). We proposed a low-complexity equalization and carrier frequency offset (CFO) compensation for UWA-OFDM-based FWHT using banded-matrix approximation concept.Simulation results show that the UWA-OFDM-based FWHT with lowdensity parity check (LDPC) codes give a good improvement performance compared with traditional OFDM in UWA system especially in case of estimation errors.peak-to-average power ratio (PAPR) at the transmitter side 8 and the carrier frequency offset (CFO) at the receiver side. 9 The PAPR results from the limited range of the power amplifier; moreover, the PAPR increases as the number of subcarriers increased. There are different algorithms used for PAPR reduction such as in previous studies. [8][9][10][11] On the other hand, the CFO results from the relative motion of the transmitter and/or receiver (Doppler effect). 12 The CFO induces intercarrier interference (ICI), which destroys the orthogonality and consequently degradation in the biterror-rate (BER) performance. 13,14 There are different algorithms used for CFO estimations such as in previous works. [15][16][17][18][19] The OFDM system lies in its simplicity by using a frequency domain equalizer (FDE) at the receiver side to mitigate the intersymbol interference (ISI) effect and improve the system performance. In the same time, we modify the OFDM system by replacing the inverse fast Fourier transform (IFFT) and fast Fourier transform (FFT) by inverse fast Walsh-Hadamard transform (IFWHT) and fast Walsh-Hadamard transform (FWHT), respectively. Replacing the FWHT/IFWHT with FFT/IFFT has been introduced in wireless radio communications, 20 which can improve the system performance. 20 But this modification requires an FFT and IFFT block to implement the FDE and enhance the system performance when compared with traditional OFDM system. On the other hand, implementation of the FWHT requires fewer computations (it omits the FFT's twiddle factors), and implement on smaller and cheaper hardware can be used to improve the performance of the UWA communication system and give better data transmission. 21 The FWHT transform can be implemented with lower complexity, due to its operation that is built on the subtraction and addition operations, while the FFT transform requires multiplication and division. 22 Also, the FWHT can be used for channel estimation with lower complexity. 22 Yang and Yang 23 show that the FWHT can be highly attentive to deal with the UWA channel impairments, and it is bu...

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