arXiv subjects

Almutasem Bellah Enad

Publications and source records attributed to Almutasem Bellah Enad.

4 recordsLinked to original sources

arXiv2026

Symbol Error Analysis of Linear Receivers in Terahertz Channels under Channel-Noise Dependence

This paper develops a comprehensive framework for the performance analysis of linear detectors, namely zero-forcing (ZF) and minimum mean-square error (MMSE), under diverse terahertz (THz) channel conditions. Three fading models are considered: Rayleigh fading, the $α$--$μ$ distribution for indoor THz environments, and the mixture-gamma (MG) distribution for outdoor THz scenarios. Semi-analytical, approximate, and asymptotic expressions for the symbol error rate (SER) are derived, explicitly incorporating the correlation between the channel and the additive noise arising from hardware impairments. This correlation is characterized using both statistical approaches and copula-based methods to effectively capture complex dependency structures. The theoretical findings are validated through simulations, demonstrating strong agreement with the derived expressions and confirming the accuracy and robustness of the proposed framework. The results demonstrate the significant impact of channel--noise dependence on THz-band receiver performance and verify the expected performance degradation of biased MMSE receivers in point-to-point links employing higher-order quadrature amplitude modulation. Specifically, at a target SER of $10^{-3}$, a 70\% correlation results in approximately a 6.5~dB degradation in the effective signal-to-noise ratio, with mismatched MMSE detection incurring an additional 1~dB loss compared to ZF. Nonetheless, MMSE offers enhanced numerical stability under severe channel fading conditions, where channel inversion causes noise amplification.

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arXiv2026

Diversity Analysis for Terahertz Communication Systems under Small-Scale Fading

The terahertz (THz) band is a key enabler for future wireless systems, promising ultra-high data rates and dense spatial reuse. However, the reliability of THz links remains a major challenge due to severe path loss and small-scale fading effects, particularly in dynamic indoor and outdoor environments. This paper presents a comprehensive diversity analysis framework for THz communication systems under small-scale fading conditions. We model fading statistically using the generalized $α$-$μ$ distribution for indoor scenarios and the mixture of gamma (MG) model for outdoor propagation. We complement previous works that analyzed diversity under the $α$-$μ$ channels [1],[2]. In particular, we present new insights on diversity for the MG channel in addition to recovering the results of [2] using a different approach. Moreover, we derive asymptotic expressions for the bit error rate as a function of the inverse signal-to-noise ratio, recovering all of the $α$-$μ$ diversity results using a simpler approximation method. The analytical results are extensively validated through Monte Carlo simulations, demonstrating excellent agreement. Our findings show that diversity gains in THz systems are strongly influenced by the number of independent paths, the severity of fading, and frequency selectivity. The proposed framework provides system designers with clear guidelines for quantifying and optimizing diversity gains in emerging channel models, paving the way for more reliable high-frequency wireless links in next-generation networks.

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arXiv2025

Performance Analysis of Linear Detection under Noise-Dependent Fast-Fading Channels

This paper presents a performance analysis framework for linear detection in fast-fading channels with possibly correlated channel and noise. The framework is both accurate and adaptable, making it well-suited for analyzing a wide range of channel and noise models. As such, it serves as a valuable tool for the design and evaluation of detection algorithms in next-generation wireless communication systems. By characterizing the distribution of the effective noise after zero-forcing filtering, we derive a semi-analytical and asymptotic expression for the symbol error rate under Rayleigh fading and channel-dependent additive circular complex Gaussian noise. The proposed approach demonstrates excellent agreement with integration-based benchmarks as confirmed by numerical simulations thus validating its accuracy. The framework is flexible and can be extended to various channel and noise models, offering a valuable tool for the design and analysis of detection algorithms in next-generation communication systems.

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arXiv2025

Performance Analysis of Data Detection in the THz-Band under Channel-Correlated Noise

We present a comprehensive symbol error rate (SER) analysis framework for link-level terahertz (THz)-band communication systems under linear zero-forcing (ZF) data detection. First, we derive the mismatched SER for indoor THz systems under independent channel and noise assumptions, calculating the probability density function of the ratio of Gaussian noise to $α$-$μ$ channels resulting from ZF filtering. Next, we derive the precise SER under correlated channel and noise conditions, modeling dependencies using the copula method. Finally, we evaluate the SER for THz channels with correlated distortion noise from hardware impairments. Simulations demonstrate that the proposed framework corrects for multi-dB SERs resulting from the channel-noise independence assumption.

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