在5G新空口(New Radio,NR)研究中提出了集成无线接入链路和无线回传链路(Integrated Access and Backhaul,IAB)的基站。IAB基站启动后其移动终端(Mobile-Termination,MT)功能将通过小区选择接入网络,因此需要保证IAB基站能够接入IAB网络...在5G新空口(New Radio,NR)研究中提出了集成无线接入链路和无线回传链路(Integrated Access and Backhaul,IAB)的基站。IAB基站启动后其移动终端(Mobile-Termination,MT)功能将通过小区选择接入网络,因此需要保证IAB基站能够接入IAB网络,从而实现IAB基站的功能。提出的5G基站(gNB)协助IAB基站接入IAB网络的方案,解决了IAB基站启动后能够最终接入IAB网络的问题。展开更多
Integral abutment bridges(IABs) are jointless bridges where the girder or the deck is continuous and connected monolithically to the abutments.A usual and important problem in the design of IABs is how to deal with th...Integral abutment bridges(IABs) are jointless bridges where the girder or the deck is continuous and connected monolithically to the abutments.A usual and important problem in the design of IABs is how to deal with the soil-structure interaction behind the abutments and next to the foundation piles: this can be considered as a fundamental aspect for the thorough understanding of this type of structures,which requires iterative and nonlinear analysis.In this paper,a 2D simplified finite-element model of a real 400 meters long IAB,built in the Province of Verona-Italy,is implemented and used to perform non linear analysis on the bridge,whose superstructure response is examined in details in the present paper.Then,the results obtained from a parametric study on the IAB,where the soil properties are varied behind the backwall and adjacent to the piles are varied,are described.In the end,a pushover analysis is carried out to assess the failure pattern of the bridge due to temperature change,considered as one of the key parameters in IABs design;finally,the effect of abutment stiffness is also discussed.The case study presented represents the world record for this kind of bridges.Authors believe this can be a cost effective and an efficient strategy to improve the durability and extend the life span of commonly built simply supported flyovers prone to maintenance problems due to bearings and expansion joints durability.展开更多
This paper aims to improve energy efficiency(EE)of the integrated access and backhaul(IAB)aerial-terrestrial network,facilitating rapid and adjustable network infrastructure deployment.This is challenging,as interfere...This paper aims to improve energy efficiency(EE)of the integrated access and backhaul(IAB)aerial-terrestrial network,facilitating rapid and adjustable network infrastructure deployment.This is challenging,as interference generated by backhaul and access links degrades network throughput,and power imbalance between these links increases overall energy consumption.To this end,we jointly optimize aerial base station(ABS)deployment,user association,and downlink power allocation for both terrestrial base station and ABSs to maximize network EE.Specifically,using fractional programming,the EE maximization problem is transformed into a subtractive-form parametric problem,and then decomposed into ABS deployment and resource allocation subproblems.A hybrid algorithm combining particle swarm optimization and simulated annealing is proposed to solve the ABS deployment subproblem,determining ABS spatial configurations and updating power allocation given fixed user association.Meanwhile,a dynamic power allocation in response to network load is designed to solve the resource allocation subproblem.Furthermore,considering the quality of service requirements of ground users and the transmit power constraints of base stations,a joint EE optimization algorithm is proposed to enhance the network EE.Simulation results validate the effectiveness of the proposed methods in improving network EE,especially in scenarios involving more deployed ABSs.展开更多
文摘在5G新空口(New Radio,NR)研究中提出了集成无线接入链路和无线回传链路(Integrated Access and Backhaul,IAB)的基站。IAB基站启动后其移动终端(Mobile-Termination,MT)功能将通过小区选择接入网络,因此需要保证IAB基站能够接入IAB网络,从而实现IAB基站的功能。提出的5G基站(gNB)协助IAB基站接入IAB网络的方案,解决了IAB基站启动后能够最终接入IAB网络的问题。
文摘Integral abutment bridges(IABs) are jointless bridges where the girder or the deck is continuous and connected monolithically to the abutments.A usual and important problem in the design of IABs is how to deal with the soil-structure interaction behind the abutments and next to the foundation piles: this can be considered as a fundamental aspect for the thorough understanding of this type of structures,which requires iterative and nonlinear analysis.In this paper,a 2D simplified finite-element model of a real 400 meters long IAB,built in the Province of Verona-Italy,is implemented and used to perform non linear analysis on the bridge,whose superstructure response is examined in details in the present paper.Then,the results obtained from a parametric study on the IAB,where the soil properties are varied behind the backwall and adjacent to the piles are varied,are described.In the end,a pushover analysis is carried out to assess the failure pattern of the bridge due to temperature change,considered as one of the key parameters in IABs design;finally,the effect of abutment stiffness is also discussed.The case study presented represents the world record for this kind of bridges.Authors believe this can be a cost effective and an efficient strategy to improve the durability and extend the life span of commonly built simply supported flyovers prone to maintenance problems due to bearings and expansion joints durability.
基金supported in part by Natural Science Foundation of China(Grant No.62121001)in part by Key Research and Development Program of Shannxi(Grant No.2024CY2-GJHX-82)in part by the Qin Chuangyuan“Scientist+Engineer”Team Construction Program of Shaanxi(Grant No.2024QCYKXJ-156).
文摘This paper aims to improve energy efficiency(EE)of the integrated access and backhaul(IAB)aerial-terrestrial network,facilitating rapid and adjustable network infrastructure deployment.This is challenging,as interference generated by backhaul and access links degrades network throughput,and power imbalance between these links increases overall energy consumption.To this end,we jointly optimize aerial base station(ABS)deployment,user association,and downlink power allocation for both terrestrial base station and ABSs to maximize network EE.Specifically,using fractional programming,the EE maximization problem is transformed into a subtractive-form parametric problem,and then decomposed into ABS deployment and resource allocation subproblems.A hybrid algorithm combining particle swarm optimization and simulated annealing is proposed to solve the ABS deployment subproblem,determining ABS spatial configurations and updating power allocation given fixed user association.Meanwhile,a dynamic power allocation in response to network load is designed to solve the resource allocation subproblem.Furthermore,considering the quality of service requirements of ground users and the transmit power constraints of base stations,a joint EE optimization algorithm is proposed to enhance the network EE.Simulation results validate the effectiveness of the proposed methods in improving network EE,especially in scenarios involving more deployed ABSs.
