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259 results on '"Liang, Xiaopeng"'

3. Beamforming Design for IRS-Aided Decode-and-Forward Relay Wireless Network

Author

Wang, Xuehui, Shu, Feng, Shi, Weiping, Liang, Xiaopeng, Dong, Rongen, Li, Jun, and Wang, Jiangzhou

Subjects
Computer Science - Information Theory
Abstract

As a low-cost and low-power-consumption passive reflector, intelligent reflecting surface (IRS) can make a significant rate improvement by building a programmable wireless environment. To improve the rate performance and coverage range of wireless networks, an IRS-aided decode-and-forward (DF) relay network is proposed with multiple antennas at relay station (RS). To achieve a high rate, an alternately iterative structure (AIS) of maximizing receive power (Max-RP) at RS is proposed to jointly optimize the beamforming vectors at RS and phase shifts at IRS. Considering its high-complexity, two low-complexity Max-RP schemes of null-space projection (NSP) plus maximum ratio combining (MRC) and IRS element selection (IRSES) plus MRC are presented to reduce this complexity, respectively. For the former, NSP is used to separate the reflected signal from IRS and the direct transmitted signal from source and MRC is adopted to combine the two signals at RS. For the latter, the basic concept of IRSES is as follows: IRS is partitioned into M subsets of elements and adjusting the phases of all elements per subset make all reflected signals and the direct signal from source phase alignment (PA) at the corresponding antenna of relay. Simulation results show that the proposed three methods perform much better than the existing network with single-antenna relay in terms of rate performance. In particular, a 85% rate gain over existing scheme is achieved in the high signal-to-noise ratio region. Moreover, it is verified that the positions of RS and IRS have a substantial impact on rate performance, and there exists an optimal positions of RS and IRS.

Published
2021

7. Research on urban landscape big data information processing system based on ordinary differential equations

Author

Yang Xuefeng, Liang Xiaopeng, Peng Lin, Liu Yue, and Elzefzafy Hend

Subjects
ordinary differential equation, big data, smart city, garden, information system, 12h20, Mathematics, QA1-939
Abstract

In view of the increasing system management requirements of garden landscapes in the construction of smart cities, this paper combines ordinary differential equations with big data and other information technologies. Design ideas of smart city garden big data information management and display system under differential equation. By analyzing the research literature, combined with space syntax, network text analysis and other methods, the theoretical framework of urban landscape planning method based on ordinary differential equations based on big data is constructed, and the aspect planning of urban garden landscape information management module, three-dimensional display module and recommendation module is determined. content. The experimental results show that the user interaction rate when using the system of this paper for information management of urban gardens shows a significant upward trend compared with the traditional system, and the average user interaction rate is higher than 40%. The application of ordinary differential equations and big data technology guides participatory planning and promotes the improvement of the information management level of smart city garden landscape. The designed information processing system has higher user experience and comfort.

Published
2023
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45. Joint Trajectory, Sensing, and Transmission Design for IRS-Assisted Cognitive UAV Systems

Author

Deng, Qian, Yu, Guangcheng, Liang, Xiaopeng, Shu, Feng, and Wang, Jiangzhou

Abstract

In this letter, the novel intelligent reflecting surface (IRS)-assisted cognitive unmanned aerial vehicle systems (CUAVS) are investigated, where the UAV serves as a mobile node sensing spectrum state of primary user (PU) and transmitting data to ground secondary users (SUs), while IRS is exploited to assist both the UAV sensing and transmission in CUAVS. Our aim is to maximize the effective throughput of CUAVS by jointly optimizing the spectrum sensing duration and the UAV’s trajectory, as well as IRS phase shift matrices in the sensing and transmission stages, where UAV needs to balance its relative location among IRS, primary transmitter, PU and SUs. To solve this challenging optimization problem, the original problem is divided into four sub-problems, and these sub-problems are solved by exploiting the bisection search, semidefinite relaxation, Gaussian randomization and successive convex approximation techniques, respectively. Numerical results demonstrate that our proposed design can significantly enhance the effective throughput of CUAVS.

Published
2024
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47. Stability Evaluation of Horizontal Salt Caverns for Gas Storage in Two Mining Layers: A Case Study in China.

Author

Zhao, Kai, Ma, Hongling, Li, Yinping, Liu, Yuanxi, Cai, Rui, Liang, Xiaopeng, Huang, Si, Zeng, Zhen, Wang, Xuan, and Li, Haoran

Subjects
GAS storage, CAVES, SALT mining, NATURAL gas storage, NATURAL gas, ROCK salt
Abstract

To increase natural gas storage capacity and further utilize salt mine resources, salt cavern gas storage in the Yunying salt mine, Hubei Province, China, was simultaneously constructed in two different mining layers (K3 and K4). The purpose of this study was to investigate the long-term feasibility of operating salt caverns for gas storage in two mining layers. Based on the geological conditions and sonar test results, the geometric parameters for the salt caverns in the two mining layers were designed, and a 3D geomechanical model was built to predict the cavern stability. The corresponding evaluation index included the displacement, volume shrinkage rate, equivalent strain, and dilatancy factor. The results show that simultaneously operating salt cavern gas storage in two mining layers is feasible, and the operational pressures for the salt caverns in mining layers K3 and K4 should be no less than 4–9 and 7–12 MPa, respectively, to satisfy the stability requirements. The surrounding rock of the salt caverns presents a larger displacement and volume reduction compared with cases in which the salt caverns are operated in a single mining layer. Increasing the injection–withdrawal frequency increases the deformation of the surrounding rock. [ABSTRACT FROM AUTHOR]

Published
2023
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