Channel Estimation for RIS Assisted Wireless Communications—Part II: An Improved Solution Based on Double-Structured Sparsity

Wei, Xiuhong; Shen, Decai; Dai, Linglong

doi:10.1109/lcomm.2021.3052787

Cited by 195 publications

(128 citation statements)

References 6 publications

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“…The system is assumed to operate at 28 GHz carrier frequency [44]. The complex gain α vi (α vi ) of the channel model described in (1) and ( 8) is subject to α vi (α vi ) ∼ CN (0, 1) distribution, and the number of paths and path loss exponent are set as 5 and 2, respectively [50]. We assume that the location of CBS, SU and PU are respectively at (−80, 29, 15)m, (0, 18.5, 18.5)m and (80, 29, 15)m. Without loss of generality, we suppose that there are two Eves, i.e., K = 2, which are situated in circular regions centered at (−44, 25.5, 18.5)m and (16, 28, 18.5)m, respectively.…”

Section: Simulation Resultsmentioning

confidence: 99%

Secure and Energy Efficient Transmission for IRS-Assisted Cognitive Radio Networks

Xing

et al. 2022

IEEE Trans. Cogn. Commun. Netw.

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Cognitive radio networks (CRNs) and millimeter wave (mmWave) communications are two major technologies to enhance the spectrum efficiency (SE). Considering that the SE improvement in the CRNs is limited due to the interference temperature imposed on the primary user (PU), and the severe path loss and high directivity in mmWave communications make it vulnerable to blockage events, we introduce an intelligent reflecting surface (IRS) into mmWave CRNs. This paper investigates the robust secure beamforming (BF) design in the IRS-assisted mmWave CRNs. By using a uniform linear array (ULA) at the cognitive base station (CBS) and a uniform planar array (UPA) at the IRS, and supposing that the imperfect channel state information (CSI) of wiretap links is known, we formulate a constrained problem to maximize the worst-case achievable secrecy rate (ASR) of the secondary user (SU) by jointly designing the transmit BF at the CBS and reflect BF at the IRS. To solve the non-convex problem with coupled variables, an efficient alternating optimization algorithm is proposed. As for the transmit BF at the CBS, we propose a heuristic robust transmit BF algorithm to attain the BF vectors analytically. As for the reflect BF at the IRS, by means of an auxiliary variable, we transform the non-convex problem into a semidefinite programming (SDP) problem with rank-1 constraint, which is handled with the help of an iterative penalty function, and then obtain the optimal reflect BF through CVX. Finally, the simulation results indicate that the ASR performance of our proposed algorithm has a small gap with that of the optimal solution with perfect CSI compared with the other benchmarks.

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Section: Simulation Resultsmentioning

confidence: 99%

Secure and Energy Efficient Transmission for IRS-Assisted Cognitive Radio Networks

Xing

et al. 2022

IEEE Trans. Cogn. Commun. Netw.

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“…This means that there is a linear correlation among JL cascaded paths, which motivates us to directly estimate J +L sparse paths, rather than estimate JL cascaded sparse paths. Note that the existing contributions in [11]- [14] estimate JL cascaded sparse paths.…”

Section: Factmentioning

confidence: 99%

“…It is observed that the CSI of the cascaded base station (BS)-IRS-user channel, which is the product of the BS-IRS channel and the IRS-user channel, is sufficient for the transmission design [6], [7]. As a result, most of the existing contributions focused on the cascaded channel estimation [8]- [14]. Specifically, consider a system containing a BS with N antennas, K singleantenna users, and one IRS with M reflecting elements.…”

Section: Introductionmentioning

confidence: 99%

“…To address this issue, the authors in [11]- [14] exploited the sparse property of the cascaded channel matrix in mmWave communication systems and proposed compressed sensing (CS)based channel estimation methods with low pilot overhead. In particular, [11] directly constructed a sparse signal recovery problem for the cascaded channel estimation and ignored the common parameters of the cascaded channel in SU-MISO system, which leads high power leakage.…”

Section: Introductionmentioning

confidence: 99%

“…In order to suppress the effect of power leakage, the atomic norm minimization method as used in [12] to estimate the sparse angles and gains. In the MU-MISO systems, both [13] and [14] investigated the double sparse structure of the cascaded channel and utilized common parameters to jointly estimate the multiuser cascaded channels with low pilot overhead and high estimation accuracy. However, these two papers assumed that the number of BS-RIS channel paths L and the number of RIS-user channel paths J are available, which is difficult to obtain these information.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Channel Estimation for RIS-Aided Multiuser Millimeter-Wave Systems

Zhou,

Pan,

Ren

et al. 2021

Preprint

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Reconfigurable intelligent surface (RIS) is a promising technique that can reconfigure the electromagnetic propagation environment by adjusting the phase shifts of the reflecting elements on the RIS. However, channel estimation in the RIS-aided massive multiuser multiple-input single-output (MU-MISO) wireless communication systems is challenging due to the passive feature of RIS and the large number of reflecting elements that incur high channel estimation overhead. To address this issue, we propose a novel cascaded channel estimation strategy with low pilot overhead by exploiting the sparsity and the correlation of multiuser cascaded channels in millimeter-wave massive MISO systems. Based on the fact that the phsical positions of the BS, the RIS and users may not change in several or even tens of consecutive channel coherence blocks, we first estimate the full channel state information (CSI) including all the angle and gain information in the first coherence block, and then only re-estimate the channel gains in the remaining coherence blocks with much less pilot overhead. In the first coherence block, we propose a two-phase channel estimation method, in which the cascaded channel of one typical user is estimated in Phase I based on the linear correlation among cascaded paths, while the cascaded channels of other users are estimated in Phase II by utilizing the partial CSI of the common base station (BS)-RIS channel obtained in Phase I. The total theoretical minimum pilot overhead in the first coherence block is 8J − 2 + (K − 1) ⌈(8J − 2)/L⌉, where K, L and J denote the numbers of users, paths in the BS-RIS channel and paths in the RIS-user channel, respectively. In each of the remaining coherence blocks, the minimum pilot overhead is JK. Moreover, the training phase shift matrices at the RIS are optimized to improve the estimation performance. Simulation results show that the performance

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The Performance Analysis on Channel Estimation in Millimeter-Wave Communication and Their Challenges

Shoukath Ali,

Ahmad Khan,

Perarasi

et al. 2024

Next Generation Wireless Communication

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Channel Estimation for RIS Assisted Wireless Communications—Part II: An Improved Solution Based on Double-Structured Sparsity

Cited by 195 publications

References 6 publications

Secure and Energy Efficient Transmission for IRS-Assisted Cognitive Radio Networks

Secure and Energy Efficient Transmission for IRS-Assisted Cognitive Radio Networks

Channel Estimation for RIS-Aided Multiuser Millimeter-Wave Systems

The Performance Analysis on Channel Estimation in Millimeter-Wave Communication and Their Challenges

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