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您的检索式：作者名="Fangyan He"
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| 1 | Energy Efficiency of Distributed Antenna Systems with D2D Communications Under Imperfect CSI显示文摘In this paper,we investigate the distributed antenna systems(DAS)based on device to device(DASD2D)communications under the imperfect channel state information(CSI).Our aim is to maximize the energy efficiency(EE)of the D2D users equipment(DUE)under the constraints of the maximum transmission power of D2D pairs and the quality of service(QoS)requirements of the cellular user equipment(CUE).The worst-case design is considered so that the QoS of the CUE can be guaranteed for every realization of the CSI error in the ellipsoid region.The EE objective function of the optimization problem is non-convex and non-linear,and thus this problem cannot be solved by the traditional optimization methods.To solve this problem,first we transform it to an EE maximization problem without uncertain parameters by exploiting the Markov and Cauchy-Schwartz inequality.Then using the fractional programming theory and difference of convex functions optimization method,the robust EE maximization algorithms based on the hard and soft protection method are developed to maximize the system’s EE performance,respectively.However,these two algorithms are designed at the cost of the reduced EE of the DUE.Therefore,in order to further improve the EE performance and make a trade-off between the EE performance and the robustness,the iterative update algorithms for the total power constraint and average interference constraint are developed to maximize the system’s EE performance,respectively.Simulation results demonstrate the effectiveness of the four proposed EE algorithms and illustrate the trade-off between the EE performance and robustness for the iterative update algorithms. | Chunlong He Fangyan Zeng Chiya Zhang Cunhua Pan Daquan Feng Fu-Chun Zheng | 2020 | Journal of Communications and Information Networks2020，5，1： | 0 |
| 2 | The effect of noise barriers on viaducts on pollutant dispersion in complex street canyons显示文摘The noise reduction effect of noise barriers has been extensively studied,but the effect on pollutant dispersion remains unclear.A computational fluid dynamics(CFD)simulation is conducted to investigate the effects of different heights,lengths,and types of noise barriers and different wind speeds on pollutant dispersion in street canyons with viaducts.The field synergy theory of the convective mass transfer process is used for quantitative analysis of pollutant dispersion in street canyons.The results show that as the height and length of the noise barrier increase,the pollutant dispersion capacity decreases.As the wind speed increases,the rate of decrease in the average CO concentration declines.The effect of the wind speed on the synergistic improvement of the speed and concentration gradient vectors differs for different types of noise barriers.The performance follows the order:fully-closed noise barrier>left noise barrier>right noise barrier>semi-closed noise barrier.The different noise barrier types significantly impact the flow field and pollutant dispersion and reduce the CO concentration to varying degrees,except for the fully-closed type.The average CO concentration in the pedestrian breathing zone is reduced by a maximum of 55.85%on the leeward side and by 53%on the windward side,indicating that an appropriate noise barrier on the viaduct reduces noise pollution and improves the air quality in street canyons,especially in the pedestrian breathing zone. | Tingzhen Ming Fangyan He Yongjia Wu Tianhao Shi Changrong Su Caixia Wang Zhengtong Li Wei Chen Renaud de Richter | 2023 | Energy and Built Environment2023，4，5： | 0 |
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