Beamforming Optimization for Intelligent Reflecting Surface Assisted MIMO: A Sum-Path-Gain Maximization Approach

Ning, Boyu; Chen, Zhi; Chen, Wenjie; Fang, Jun

doi:10.1109/lwc.2020.2982140

Cited by 143 publications

(83 citation statements)

References 11 publications

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“…e characteristics of the supply chain in the craft industry include sales/brand enterprise as the core; rapid changes in market demand; orderoriented production; short supply chain cycle; complex product information management; a globalized ecosystem. Facing the increasingly competitive market environment, it is an inevitable trend for international handicraft enterprises to accelerate the development of e-commerce and information technology, which will help them increase foreign trade channels, reduce transaction costs, simplify business processes, and shorten production cycles [10].…”

Section: Introductionmentioning

confidence: 99%

[Retracted] Optimization of Intelligent Management System for Crafts Production Based on Internet of Things

Xiao-Hong

2021

Complexity

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Crafts are a special kind of personalized goods that can be personalized with the help of the Internet to better meet consumers’ individuality and make them part of the personalized craft design. The development of information technology has made it possible to grasp personal information and talk to individuals, and the past practice of grasping consumers’ needs by age level has become obsolete, and providing one-to-one product service to customers through the Internet will become a new market growth point. The design and implementation of the system hardware are introduced by focusing on the functional circuits of various sensors of the data collection terminal, The functional circuit of the wireless communication module CC2530, the functional circuit of the microprocessor STM32, and the functional circuit of the collection terminal. In addition, this paper introduces the development environment of IAR software, the implementation of sensor acquisition function, 4 G module communication function, and coordinator network from the software point of view and provides a detailed explanation using program flowcharts. Next, by comparing the three filtering algorithms, an error optimization algorithm can be used to optimize the filtered data errors and obtain better results. By establishing an experimental platform for collecting all kinds of data, a network formation experiment is performed, and the coordinator normally forms the network, and the collected and processed data by the algorithm are matched to the MATLAB simulation platform. The Topix is compared with the exact data measured by the sensor. Finally, calculations show that two dry batteries can be used to maintain the system over 6 months. The system provides power and low-power design is practical and effective.

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Section: Introductionmentioning

confidence: 99%

[Retracted] Optimization of Intelligent Management System for Crafts Production Based on Internet of Things

Xiao-Hong

2021

Complexity

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“…The local search method just achieves the suboptimal data rate performance while it can greatly decrease the computational complexity. According to [59], the elements of the diagonal matrix { (i, i)} N s i=1 are regarded as the virtual path gains. and the phase shift matrix is influenced by the virtual path gains.…”

Section: B Local Search Schemementioning

confidence: 99%

Joint Channel Estimation and Data Rate Maximization for Intelligent Reflecting Surface Assisted Terahertz MIMO Communication Systems

et al. 2020

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Terahertz (THz) communications recently attract significant attention and become an emerging technology pillar for sixth generation (6G) wireless systems. Due to the serious path attenuation of THz signals, THz communication is applicable for the short-distance indoor scenarios. However, the THz waves are easily blocked by obstacles, leading to a communication interruption. To this end, an intelligent reflecting surface (IRS), which interacts with incident THz waves in a controlled manner by adjusting the discrete phase shifts of the IRS elements, is considered as a promising technology to mitigate blockage vulnerability and enhance coverage capability for indoor scenarios. In light of graphene-enabled hardware structure of an IRS, the IRS-assisted THz multiple-input multiple-output (MIMO) system model is developed. Moreover, an iterative atom pruning based subspace pursuit (IAP-SP) scheme is developed for channel estimation. Compared to the classical subspace pursuit (SP) scheme, the proposed IAP-SP algorithm can substantially reduce the computational complexity while maintaining accurate channel recovery. With the estimated channel, a data rate maximization problem is formulated, which can be converted to a discrete phase shift search problem. The exhaustive search method is firstly proposed to obtain the optimal transmission rate but endure extremely high computational burden. Then, a local search method is proposed to decrease the number of possible discrete phase candidates of IRS while undergoes obvious performance loss. Interestingly, a novel feedforward fully connected structure based deep neural network (DNN) scheme is put forward, which has the ability to learn how to output the optimal phase shift configurations by inputting the features of estimated channel. Simulation results demonstrate that, in contrast with the exhaustive search scheme and the local search scheme, the proposed DNN-based scheme achieves a near-optimal communication rate performance. Meanwhile, the DNN-based scheme enormously alleviates the computational complexity and allows for dynamic parameter adaption in rapid-varying channel conditions. INDEX TERMS Terahertz (THz) communications, sixth generation (6G), intelligent reflecting surface (IRS), channel estimation, deep neural network (DNN).

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“…However, it remains nonconvex and thus is hard to be solved optimally. Regarding this, Ning et al [17] first propose to reformulate it into a relaxed problem of maximizing sum-path gains, which can be effectively solved by ADMM. Then, Zhang et al [18] provide a more strict reformulation and proposed an alternating optimization (AO)based algorithm to obtain a high-performance solution to this problem.…”

Section: Literature Reviewmentioning

confidence: 99%

“…Specifically, we decouple the optimization problem and derive the optimal baseband beamforming design for a given IRS configuration. Based on the relaxed problem given in [17], the passive beamforming design problem is formulated as a nonconvex quadratically constrained quadratic program (QCQP), subject to the constant modulus constraints imposed by IRS elements.…”

Section: Contributionsmentioning

confidence: 99%

Passive beamforming design for intelligent reflecting surface assisted MIMO systems

et al. 2021

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Intelligent reflecting surfaces (IRSs) constitute passive devices, which are capable of adjusting the phase shifts of their reflected signals, and hence they are suitable for passive beamforming. In this paper, we conceive their design with the active beamforming action of multiple-input multipleoutput (MIMO) systems used at the access points (APs) for improving the beamforming gain, where both the APs and users are equipped with multiple antennas. Firstly, we decouple the optimization problem and design the active beamforming for a given IRS configuration. Then we transform the optimization problem of the IRS-based passive beamforming design into a tractable non-convex quadratically constrained quadratic program (QCQP). For solving the transformed problem, we give an approximate solution based on the technique of widely used semidefinite relaxation (SDR). We also propose a low-complexity iterative solution. We further prove that it can converge to a locally optimal value. Finally, considering the practical scenario of discrete phase shifts at the IRS, we give the quantization design for IRS elements on basis of the two solutions. Our simulation results demonstrate the superiority of the proposed solutions over the relevant benchmarks.

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Beamforming Optimization for Intelligent Reflecting Surface Assisted MIMO: A Sum-Path-Gain Maximization Approach

Cited by 143 publications

References 11 publications

[Retracted] Optimization of Intelligent Management System for Crafts Production Based on Internet of Things

[Retracted] Optimization of Intelligent Management System for Crafts Production Based on Internet of Things

Joint Channel Estimation and Data Rate Maximization for Intelligent Reflecting Surface Assisted Terahertz MIMO Communication Systems

Passive beamforming design for intelligent reflecting surface assisted MIMO systems

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