Safeguarding MIMO Communications with Reconfigurable Metasurfaces and Artificial Noise

Alexandropoulos, George C.; Katsanos, Konstantinos; Wen, Miaowen; Costa, Daniel Benevides da

doi:10.1109/icc42927.2021.9501003

Cited by 47 publications

(28 citation statements)

References 24 publications

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“…On the contrary, the CDS not only requires complex products for performing the post-coding, but it also requires to solve the optimization problem to obtain the BS combining vector and the RS phase configuration. In order to constrain the complexity, the considered baseline CDS implements the iterative method of [12] at the expense of reducing the performance, whose complexity linearly scales with the number of algorithmic iterations required iterations, 𝑅 𝑡 , the number 𝑀 of RS passive elements, and the number 𝐾 of OFDM subcarriers.…”

Section: B Complexity Analysismentioning

confidence: 99%

Non-Coherent MIMO-OFDM Uplink empowered by the Spatial Diversity in Reflecting Surfaces

Chen‐Hu¹,

Alexandropoulos²,

Armada³

2022

Preprint

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Reflecting Surfaces (RSs) are being lately envisioned as an energy efficient solution capable of enhancing the signal coverage in cases where obstacles block the direct communication from Base Stations (BSs), especially at high frequency bands due to attenuation loss increase. In the current literature, wireless communications via RSs are exclusively based on traditional coherent demodulation, which necessitates the estimation of accurate Channel State Information (CSI). However, this requirement results in an increased overhead, especially in time-varying channels, which reduces the resources that can be used for data communication. In this paper, we consider the uplink between a single-antenna user and a multi-antenna BS and present a novel RS-empowered Orthogonal Frequency Division Multiplexing (OFDM) communication system based on the differential phase shift keying, which is suitable for high noise and/or mobility scenarios. As a benchmark, analytical expressions for the Signal-to-Interference and Noise Ratio (SINR) of the proposed system are presented. Our extensive simulation results verify the accuracy of the presented analysis and showcase the performance and superiority of the proposed system over coherent demodulation.

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Section: B Complexity Analysismentioning

confidence: 99%

Non-Coherent MIMO-OFDM Uplink empowered by the Spatial Diversity in Reflecting Surfaces

Chen‐Hu¹,

Alexandropoulos²,

Armada³

2022

Preprint

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“…Alternatively, at the expense of sacrificing performance and accelerating the solution, (V-B) can be sub-optimally tackled [44] with the following iterative approach. Keeping ψ fixed ∀ , the optimum w , is obtained ∀ as w opt , = v max (C , , ψ ψ C , , ), while for fixed w , ∀ , , the optimum ψ is computed as ψ opt = exp ( arg(C , , w , )).…”

Section: B Ris Configuration Optimization and Feedbackmentioning

confidence: 99%

“…In most of the previous works [1], [3], [4], [22], [44], [45], it has been assumed for the purpose of CDS for the RIS-empowered link that the coherence time, , is always long enough so that the duration of channel training does not penalize the duration of the data transmission stage. However, even with low mobility, the cascaded channel will suffer from a certain time variability and its estimation must be periodically updated.…”

Section: Efficiency Factormentioning

confidence: 99%

“…Different suboptimal methods can be proposed to avoid the complexity issue, at the expense of decreasing the overall performance. In order to constrain the complexity, the considered baseline CDS implements the iterative method of [44], whose complexity linearly scales with the number of algorithmic iterations required iterations, , the number of RIS passive elements, and the number of OFDM subcarriers. It is noted that the CDS complexity increases severely with the number of BS antennas (it depends on 3 ), which indicates that a massive MIMO BS is not recommended in RIS-empowered systems based on CDS.…”

Section: B Complexity Analysismentioning

confidence: 99%

“…FOR THE GEOMETRIC WIDEBAND CHANNEL MODEL Similar to the previous appendix, we hereinafter present the derivation of closed-form expression for the interference and noise terms required in (24) for the considered geometric wideband channel model. We again assume quasi-static channels between any two contiguous OFDM symbols with 2 ≤ ≤ , and focusing on any -th particular subcarrier we define as in (44) as well as H , and g , as follows:…”

Section: Appendix B Expected Values Of the Interference And Noisementioning

confidence: 99%

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Non-Coherent Modulation for RIS-Empowered Multi-Antenna OFDM Communications

Chen-Hu,

Alexandropoulos,

Armada

2021

Preprint

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The Reconfigurable Intelligent Surface (RIS) constitutes one of the prominent technologies for the next 6-th Generation (6G) of wireless communications. It is envisioned to enhance signal coverage in cases where obstacles block the direct communication from Base Stations (BSs), and when high carrier frequencies are used that are sensitive to attenuation losses. In the literature, the exploitation of RISs is exclusively based on traditional coherent demodulation, which necessitates the availability of Channel State Information (CSI). Given the CSI, a multi-antenna BS or a dedicated controller computes the pre/post spatial coders and the RIS configuration. The latter tasks require significant amount of time and resources, which may not be affordable when the channel is time-varying or the CSI is not accurate enough. In this paper, we consider the uplink between a single-antenna user and a multi-antenna BS and present a novel RIS-empowered Orthogonal Frequency Division Multiplexing (OFDM) communication system based on the differential phase shift keying, which is suitable for high noise and/or mobility scenarios. Considering both an idealistic and a realistic channel model, analytical expressions for the Signal-to-Interference and Noise Ratio (SINR) and the Symbol Error Probability (SEP) of the proposed non-coherent RIS-empowered system are presented. Our extensive computer simulation results verify the accuracy of the presented analysis and showcase the proposed system's performance and superiority over coherent demodulation in different mobility and spatial correlation scenarios.

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Reconfiguring wireless environments via intelligent surfaces for 6G: reflection, modulation, and security

Yuen

Huang

et al. 2023

Sci. China Inf. Sci.

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Safeguarding MIMO Communications with Reconfigurable Metasurfaces and Artificial Noise

Cited by 47 publications

References 24 publications

Non-Coherent MIMO-OFDM Uplink empowered by the Spatial Diversity in Reflecting Surfaces

Non-Coherent MIMO-OFDM Uplink empowered by the Spatial Diversity in Reflecting Surfaces

Non-Coherent Modulation for RIS-Empowered Multi-Antenna OFDM Communications

Reconfiguring wireless environments via intelligent surfaces for 6G: reflection, modulation, and security

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