Performance Evaluation of Reconfigurable Intelligent Surface against Distributed Antenna System at the Cell Edge

Kamaruddin, Nuraqila Alini; Mahmud, Azwan; Alias, Mohamad Yusoff; Aziz, Azlan Abd; Yaakob, Syamsuri

doi:10.3390/electronics11152376

Cited by 4 publications

(10 citation statements)

References 20 publications

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“…Therefore, it becomes necessary to consider Nakagami-m fading channels, which offer a more realistic representation of the practical scenario. Most of the research works that consider the Nakagami-m fading model employ the CLT and gammabased approximation methods [13], [15], [18]- [20], [24]- [26]. These approximation methods are commonly used for the statistical properties of IRS-assisted systems due to the lack of closed-form expressions.…”

Section: A Related Work and Motivationmentioning

confidence: 99%

A Novel Stochastic Model for IRS-Assisted Communication Systems Based on the Sum-Product of Nakagami-m Random Variables

Amiriara,

Mirmohseni,

Ashtiani

et al. 2024

IEEE Open J. Commun. Soc.

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This paper presents exact formulas for the probability distribution function (PDF) and moment generating function (MGF) of the sum-product of statistically independent but not necessarily identically distributed (i.n.i.d.) Nakagami-m random variables (RVs) in terms of Meijer's G-function. Additionally, exact series representations are also derived for the sum of double-Nakagami RVs, providing useful insights on the trade-off between accuracy and computational cost. Simple asymptotic analytical expressions are provided to gain further insight into the derived formula, and the achievable diversity order is obtained. The suggested statistical properties are proved to be a highly useful tool for modeling parallel cascaded Nakagami-m fading channels. The application of these new results is illustrated by deriving exact expressions and simple tight upper bounds for the outage probability (OP) and average symbol error rate (ASER) of several binary and multilevel modulation signals in intelligent reflecting surfaces (IRSs)-assisted communication systems operating over Nakagami-m fading channels. It is demonstrated that the new asymptotic expression is highly accurate and can be extended to encompass a wider range of scenarios. To validate the theoretical frameworks and formulations, Monte-Carlo simulation results are presented. Additionally, supplementary simulations are provided to compare the derived results with two common types of approximations available in the literature, namely the central limit theorem (CLT) and gamma distribution.INDEX TERMS Nakagami-m distribution, moment generating function (MGF), Intelligent reflecting surfaces (IRS), average symbol error rates (ASER), outage probability (OP).

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Section: A Related Work and Motivationmentioning

confidence: 99%

A Novel Stochastic Model for IRS-Assisted Communication Systems Based on the Sum-Product of Nakagami-m Random Variables

Amiriara,

Mirmohseni,

Ashtiani

et al. 2024

IEEE Open J. Commun. Soc.

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“…A comprehensive, detailed survey of RIS technology limitations in current research, related research opportunities, and possible solutions was presented. Moreover, the study in [16] compared the RIS-assisted system with the distributed antenna-aided system. However, the non-line-of-site link between the transmitter and receiver was not considered.…”

Section: Related Workmentioning

confidence: 99%

“…Due to their physical resemblance to mirrors, they may also be simply put on building facades, factory ceilings, and interior walls. Because of its capability to reconfigure signals, the RIS has some of the most advantageous use cases for line-of-site (LOS) paths or at the cell edge [15,16]. RIS neither amplifies nor decodes the incoming signal, unlike conventional relaying methods, such as amplify-and-forward (AF) and decode-andforward (DF) relaying [15,17].…”

Section: Introductionmentioning

confidence: 99%

Cross-Tier Interference Mitigation for RIS-Assisted Heterogeneous Networks

Soumana Hamadou,

wa Maina,

Soidridine

2023

Technologies

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With the development of the next generation of mobile networks, new research challenges have emerged, and new technologies have been proposed to address them. On the other hand, reconfigurable intelligent surface (RIS) technology is being investigated for partially controlling wireless channels. RIS is a promising technology for improving signal quality by controlling the scattering of electromagnetic waves in a nearly passive manner. Heterogeneous networks (HetNets) are another promising technology that is designed to meet the capacity requirements of the network. RIS technology can be used to improve system performance in the context of HetNets. This study investigates the applications of reconfigurable intelligent surfaces (RISs) in heterogeneous downlink networks (HetNets). Due to the network densification, the small cell base station (SBS) interferes with the macrocell users (MUEs). In this paper, we utilise RIS to mitigate cross-tier interference in a HetNet via directional beamforming by adjusting the phase shift of the RIS. We consider RIS-assisted heterogeneous networks consisting of multiple SBS nodes and MUEs that utilise both direct paths and reflected paths. Therefore, the aim of this study is to maximise the sum rate of all MUEs by jointly optimising the transmit beamforming of the macrocell base station (MBS) and the phase shift of the RIS. An efficient RIS reflecting coefficient-based optimisation (RCO) is proposed based on a successive convex approximation approach. Simulation results are provided to show the effectiveness of the proposed scheme in terms of its sum rate in comparison with the scheme HetNet without RIS and the scheme HetNet with RIS but with random phase shifts.

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“…1) RIS without Direct Link: In [6], [11], [21]- [25], [28]- [34], the authors provide closed-form exact and approximations for several performance metrics through modeling the end-to-end RIS channel amplitude as Rayleigh [6], [30], Gamma [11], [26], [27], and Nakagami-m [28] distributions. Moreover, the channel [24], [25], [29] is based on Central Limit Theorem (CLT) which is not accurate for a small number of reflecting elements. In [33], a unified analytical framework is developed based on the Fox-H function, which is shown to be highly accurate even for a small number of reflecting elements, particularly for continuous phase shifts.…”

Section: A Related Workmentioning

confidence: 99%

“…By noting the superposition of H D and H R in (7), then the PDF of V can be obtained by applying the convolution theorem to (22) and (25). Thus,…”

Section: Pdf Of the Received Signal Powermentioning

confidence: 99%

On the Performance of RIS-Assisted Communications With Direct Link Over κ-μ Shadowed Fading

Al-Rimawi

Al-Dweik

2022

IEEE Open J. Commun. Soc.

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In reconfigurable intelligent surface (RIS)-assisted communications, the signal-to-noise ratio (SNR) is improved by optimizing the reflecting elements' phases to make the reflected signals add coherently at the receiver. Nevertheless, the RIS cannot control the phase of the direct link if it exists. Although the RIS phase can still be controlled such that the direct and reflected signals add coherently, the SNR gain might be hindered. Therefore, this paper considers the performance analysis of such scenarios where a novel analytical framework is developed to evaluate the SNR, outage probability, and bit error rate (BER). To capture a broad range of fading conditions, the channels are modeled as independent but not identically distributed generalized κ-µ shadowed fading channels. The Laplace transform is used to derive an accurate approximation of the probability density function (PDF) and cumulative distribution function (CDF) of the instantaneous fading, which are used to derive the PDF and CDF of the instantaneous SNR. The paper also considers deriving the asymptotic PDF, CDF, moment generating function (MGF) of the SNR, as well as the outage probability and BER. The obtained results show that a strong direct link may limit the gain obtained using the RIS.

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Performance Evaluation of Reconfigurable Intelligent Surface against Distributed Antenna System at the Cell Edge

Cited by 4 publications

References 20 publications

A Novel Stochastic Model for IRS-Assisted Communication Systems Based on the Sum-Product of Nakagami-m Random Variables

A Novel Stochastic Model for IRS-Assisted Communication Systems Based on the Sum-Product of Nakagami-m Random Variables

Cross-Tier Interference Mitigation for RIS-Assisted Heterogeneous Networks

On the Performance of RIS-Assisted Communications With Direct Link Over κ-μ Shadowed Fading

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