Joint low‐complexity nonlinear equalization and carrier frequency offset compensation for multiple‐input multiple‐output orthogonal frequency division multiplexing communication systems

Ramadan, Khaled; Dessouky, Moawad I.; El‐Samie, Fathi E. Abd

doi:10.1002/ett.3874

Cited by 11 publications

(9 citation statements)

References 45 publications

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“…In this paper, the suggested configuration in Figure 2D is comparable with the traditional configuration. Generally, the matrix‐matrix multiplication of dimensions N × N needs approximately N 3 complex additions and N 3 complex multiplications 12 . Equation (6) shows that an LMMSE equalizer requires two complex multiplications of matrices and a complex matrix inversion with α = 1/ SNR , and Π = π .There is a need for six operations for achieving the multiplication of two complex numbers 23 .…”

Section: Simulation Resultsmentioning

confidence: 99%

“…Therefore, if the CFO appears, the orthogonality is damaged, which leads to ICI. Generally, the condition of orthogonality in the case of traditional DFT can be expressed as 16 :

\frac{1}{N} \sum_{n = 0}^{N - 1} e^{j \frac{2 π false(m - p false) n}{N}} = \{\begin{matrix} 1 for m = p \\ 0 for m \neq p \end{matrix}

The matrix of interference due to the loss of orthogonality in the case of DFT can be expressed as 12‐18 :

{({boldη}_{m, p})}_{normalDFT} = \exp (\frac{j π [(m - p) + ε] (N - 1)}{N}) . \frac{\sin false(π false[false(m - p false) + ε false] false)}{N . \sin (\frac{π [(m - p) + ε]}{N})}

…”

Section: The Proposed Communication Systemmentioning

confidence: 99%

“…The OFDM is based on modulation of multiple carriers, and therefore it improves the overall efficiency of the UWA system 10 . It suffers from two main drawbacks: at the transmitter side, the large Peak‐to‐ Average Power Ratio (PAPR) problem, and at the receiver side, the Carrier Frequency Offset (CFO) problem 11,12 . For PAPR reduction, various methods that depend on Discrete Fourier Transform Spread Orthogonal Frequency Division Multiplexing (DFT‐SOFDM), and Discrete Cosine Transform (DCT) have been used 11‐13 .…”

Section: Introductionmentioning

confidence: 99%

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Performance improvement of data transmission using a hybrid underwater and terrestrial system

Ramadan

Taha

Dessouky

et al. 2021

Trans Emerging Tel Tech

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In this paper, we investigate and enhance the performance of data transmission using a hybrid underwater and terrestrial system with low‐complexity linear equalization. Due to the low speed, salinity, water depth, pH degree, and water temperature variations, underwater acoustic communication has become one of the most challenging technologies in the world. The most common linear equalizers are the Linear Zero Forcing (LZF), and Linear Minimum Mean Square Error (LMMSE) equalizers. The LZF equalizer suffers from the noise enhancement problem, while the LMMSE equalizer requires the value of the operating Signal‐to‐Noise Ratio (SNR) to work, correctly, which increases the computational complexity. In addition, this paper presents a low‐complexity equalization scheme to overcome the drawbacks associated with the LZF, and LMMSE equalizers. The proposed equalizer is called the Joint Low‐Complexity Regularized LZF equalizer, which depends on a fixed regularization parameter to minimize the noise enhancement phenomenon caused by the LZF equalizer. The proposed equalizer does not need the estimation of the SNR, and the computational complexity is reduced due to the utilization of the banded‐matrix approximation. The proposed equalizer is implemented based on the Single‐Input‐Single‐Output configuration for Orthogonal Frequency Division Multiplexing (OFDM) using the Discrete Cosine Transform. The obtained simulation results show that the proposed equalizer outperforms different equalizers for the same channel conditions.

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Section: Simulation Resultsmentioning

confidence: 99%

“…Therefore, if the CFO appears, the orthogonality is damaged, which leads to ICI. Generally, the condition of orthogonality in the case of traditional DFT can be expressed as 16 :

\frac{1}{N} \sum_{n = 0}^{N - 1} e^{j \frac{2 π false(m - p false) n}{N}} = \{\begin{matrix} 1 for m = p \\ 0 for m \neq p \end{matrix}

The matrix of interference due to the loss of orthogonality in the case of DFT can be expressed as 12‐18 :

{({boldη}_{m, p})}_{normalDFT} = \exp (\frac{j π [(m - p) + ε] (N - 1)}{N}) . \frac{\sin false(π false[false(m - p false) + ε false] false)}{N . \sin (\frac{π [(m - p) + ε]}{N})}

…”

Section: The Proposed Communication Systemmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Performance improvement of data transmission using a hybrid underwater and terrestrial system

Ramadan

Taha

Dessouky

et al. 2021

Trans Emerging Tel Tech

Self Cite

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show abstract

“…It uses the concept of banded‐matrix approximation. In another previous work, 24 the authors proposed a low‐complexity nonlinear equalizer for OFDM communication systems based on DFT. In the same manner, low‐complexity nonlinear equalization schemes for OFDM communication systems based on Discrete Sine Transform (DST) 28 and Discrete Wavelet Transform (DWT) 25 were proposed to improve the BER system performance.…”

Section: Introductionmentioning

confidence: 99%

On the performance of joint low‐complexity equalization and CFO compensation for SISO‐OFDM communication systems with chaotic interleaving and DCT

Ramadan

Alturki

Dessouky

et al. 2021

Int J Communication

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The implementation of the Orthogonal Frequency Division Multiplexing (OFDM) can be achieved using Inverse Discrete Cosine Transform (IDCT), and DCT instead of Inverse Discrete Fourier Transform (IDFT), and DFT. The Carrier Frequency Offset (CFO) is the main issue of the OFDM system. One of the tools to mitigate the CFO effect and improve the Bit-Error-Rate (BER) performance is the equalization procedure. Also, the 1-Dimension (1-D), and 2-Dimension (2-D) burst errors can be mitigated using a chaotic interleaver in the OFDM system. This consequently improves the BER performance. In this paper, we propose a Joint Low-Complexity Regularized Linear Zero Forcing (JLCRLZF) equalizer for the OFDM system based on DCT in addition to a chaotic interleaving scheme. The proposed equalizer depends on the concept of the banded-matrix approximation, and jointly performs the equalization and CFO compensation processes. Simulation results ensure the importance of the proposed JLCRLZF equalizer compared to other algorithms.

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“…The advantage of the MIMO technology is further strengthened as the number of antennas used increases, but there is a problem in that the complexity is greatly increased. Since various studies are currently being conducted to overcome such complexity problems, 16,17 it will be more actively applied to various communication systems occurring in the future.…”

Section: Introductionmentioning

confidence: 99%

Multiple‐input multiple‐output system design of multidimensional orthogonal frequency division multiplexing system with coded direct index modulation

Ryu

2021

Trans Emerging Tel Tech

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In this paper, two kinds of design methods of combining the multidimensional (MD) orthogonal frequency division multiplexing (OFDM) with coded direct index modulation (CDIM) system and multiple-input multiple-output (MIMO) technology are proposed to increase the spectrum efficiency more. These systems can be called as dimension-dependent system and dimension-independent system, respectively. MD-OFDM-CDIM was proposed to overcome the limitations of the spectral efficiency of MD-OFDM. It has some advantages in terms of spectral efficiency and the performance is comparable to OFDM. However, there is a lack of compatibility studies with MIMO to increase the spectral efficiency. Therefore, in this paper, the compatibility of MD-OFDM-CDIM with MIMO is shown and the performance of the combined MIMO MD-OFDM-CDIM systems is evaluated. The simulation results show that the performance of the two proposed systems are similar under the conditions for the same spectral efficiency. However, the dimension-independent system is better than the dimension-dependent system because the reception processing complexity of the dimension-dependent system increases significantly as the numbers of transmission and reception antennas go to higher.

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Joint low‐complexity nonlinear equalization and carrier frequency offset compensation for multiple‐input multiple‐output orthogonal frequency division multiplexing communication systems

Cited by 11 publications

References 45 publications

Performance improvement of data transmission using a hybrid underwater and terrestrial system

Performance improvement of data transmission using a hybrid underwater and terrestrial system

On the performance of joint low‐complexity equalization and CFO compensation for SISO‐OFDM communication systems with chaotic interleaving and DCT

Multiple‐input multiple‐output system design of multidimensional orthogonal frequency division multiplexing system with coded direct index modulation

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