Intelligent Reflecting Surface Aided Wireless Systems with Imperfect Hardware
In this article, we investigate the design of reconfigurable intelligent surface (RIS)-aided transmission as a smart method to reflect signals received from access points to users and, hence, improving users’ performance. To implement smart Internet of Things (IoT) networks, massive connectivity and...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-03-01
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| Series: | Electronics |
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| Online Access: | https://www.mdpi.com/2079-9292/11/6/900 |
| _version_ | 1797446766581252096 |
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| author | Nhan Duc Nguyen Anh-Tu Le Munyaradzi Munochiveyi Fatemeh Afghah Evangelos Pallis |
| author_facet | Nhan Duc Nguyen Anh-Tu Le Munyaradzi Munochiveyi Fatemeh Afghah Evangelos Pallis |
| author_sort | Nhan Duc Nguyen |
| collection | DOAJ |
| description | In this article, we investigate the design of reconfigurable intelligent surface (RIS)-aided transmission as a smart method to reflect signals received from access points to users and, hence, improving users’ performance. To implement smart Internet of Things (IoT) networks, massive connectivity and low-cost deployment are essential in designing such systems. In particular, we consider two practical scenarios (dual-hop and single-hop transmissions). These scenarios highlight the potential of RIS in enhancing the system’s outage probability performance. Furthermore, to characterize channel conditions in practice, we pay particular attention to two-channel distributions that are non-central chi-square (NCCS) distributions that approximate the channel distribution of the RIS-aided wireless system and the squared <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>K</mi><mi>G</mi></msub></semantics></math></inline-formula> distribution. In addition, the RIS-aided system may face imperfect hardware-related issues in practice. Therefore, we need to consider the degraded performance of practical RIS-aided systems by considering the detrimental impact of in-phase and quadrature-phase imbalance (IQI). To characterize the main system performance metric, we provide closed-form formulas of outage probability and ergodic capacity. We then evaluate system performance under the impacts of signal-to-noise ratio (SNR), the number of meta-surfaces, and channel parameters. All closed-form outage expressions are validated via Monte Carlo simulations. Simulation results indicate that the considered RIS scheme at dual-hop and single hop under the impact of IQI and RIS hardware impairment achieves significant improvements in terms of outage probability at high SNR and high meta-surface number N. Additionally, the simulation results demonstrate that the impact of IQI on the proposed system is limited. It is worth noting that, in terms of ergodic capacity, ergodic capacity faces an upper limit. Despite this limitation, the proposed system can still work well once some parameters are controlled well, such as the transmit SNR, levels of IQI, and the number of RIS components. |
| first_indexed | 2024-03-09T13:45:18Z |
| format | Article |
| id | doaj.art-81c56d32d85a42618f3ada86e63c0a48 |
| institution | Directory Open Access Journal |
| issn | 2079-9292 |
| language | English |
| last_indexed | 2024-03-09T13:45:18Z |
| publishDate | 2022-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Electronics |
| spelling | doaj.art-81c56d32d85a42618f3ada86e63c0a482023-11-30T21:01:06ZengMDPI AGElectronics2079-92922022-03-0111690010.3390/electronics11060900Intelligent Reflecting Surface Aided Wireless Systems with Imperfect HardwareNhan Duc Nguyen0Anh-Tu Le1Munyaradzi Munochiveyi2Fatemeh Afghah3Evangelos Pallis4Faculty of Engineering, Van Lang University, Ho Chi Minh City 700000, VietnamFaculty of Electronics Technology, Industrial University of Ho Chi Minh City, Ho Chi Minh City 700000, VietnamDepartment of Electrical and Electronics Engineering, University of Zimbabwe, Mount Pleasant, Harare MP167, ZimbabweElectrical and Computer Engineering Department, Clemson University, Clemson, SC 29634, USAElectrical and Computer Engineering, Hellenic Mediterranean University, 71004 Heraklion, Crete, GreeceIn this article, we investigate the design of reconfigurable intelligent surface (RIS)-aided transmission as a smart method to reflect signals received from access points to users and, hence, improving users’ performance. To implement smart Internet of Things (IoT) networks, massive connectivity and low-cost deployment are essential in designing such systems. In particular, we consider two practical scenarios (dual-hop and single-hop transmissions). These scenarios highlight the potential of RIS in enhancing the system’s outage probability performance. Furthermore, to characterize channel conditions in practice, we pay particular attention to two-channel distributions that are non-central chi-square (NCCS) distributions that approximate the channel distribution of the RIS-aided wireless system and the squared <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>K</mi><mi>G</mi></msub></semantics></math></inline-formula> distribution. In addition, the RIS-aided system may face imperfect hardware-related issues in practice. Therefore, we need to consider the degraded performance of practical RIS-aided systems by considering the detrimental impact of in-phase and quadrature-phase imbalance (IQI). To characterize the main system performance metric, we provide closed-form formulas of outage probability and ergodic capacity. We then evaluate system performance under the impacts of signal-to-noise ratio (SNR), the number of meta-surfaces, and channel parameters. All closed-form outage expressions are validated via Monte Carlo simulations. Simulation results indicate that the considered RIS scheme at dual-hop and single hop under the impact of IQI and RIS hardware impairment achieves significant improvements in terms of outage probability at high SNR and high meta-surface number N. Additionally, the simulation results demonstrate that the impact of IQI on the proposed system is limited. It is worth noting that, in terms of ergodic capacity, ergodic capacity faces an upper limit. Despite this limitation, the proposed system can still work well once some parameters are controlled well, such as the transmit SNR, levels of IQI, and the number of RIS components.https://www.mdpi.com/2079-9292/11/6/900reconfigurable intelligent surface (RIS)outage probabilityin-phase and quadrature-phase imbalance (IQI) |
| spellingShingle | Nhan Duc Nguyen Anh-Tu Le Munyaradzi Munochiveyi Fatemeh Afghah Evangelos Pallis Intelligent Reflecting Surface Aided Wireless Systems with Imperfect Hardware Electronics reconfigurable intelligent surface (RIS) outage probability in-phase and quadrature-phase imbalance (IQI) |
| title | Intelligent Reflecting Surface Aided Wireless Systems with Imperfect Hardware |
| title_full | Intelligent Reflecting Surface Aided Wireless Systems with Imperfect Hardware |
| title_fullStr | Intelligent Reflecting Surface Aided Wireless Systems with Imperfect Hardware |
| title_full_unstemmed | Intelligent Reflecting Surface Aided Wireless Systems with Imperfect Hardware |
| title_short | Intelligent Reflecting Surface Aided Wireless Systems with Imperfect Hardware |
| title_sort | intelligent reflecting surface aided wireless systems with imperfect hardware |
| topic | reconfigurable intelligent surface (RIS) outage probability in-phase and quadrature-phase imbalance (IQI) |
| url | https://www.mdpi.com/2079-9292/11/6/900 |
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