The fifth generation(5 G) wireless communication is currently a hot research topic and wireless communication systems on high speed railways(HSR) are important applications of 5 G technologies. Existing studies about ...The fifth generation(5 G) wireless communication is currently a hot research topic and wireless communication systems on high speed railways(HSR) are important applications of 5 G technologies. Existing studies about 5 G wireless systems on high speed railways(HSR) often utilize ideal channel parameters and are usually based on simple scenarios. In this paper, we evaluate the downlink throughput of 5 G HSR communication systems on three typical scenarios including urban, cutting and viaduct with three different channel estimators. The channel parameters of each scenario are generated with tapped delay line(TDL) models through ray-tracing simulations, which can be considered as a good match to practical situations. The channel estimators including least square(LS), linear minimum mean square error(LMMSE), and our proposed historical information based basis expansion model(Hi BEM). We analyze the performance of the Hi BEM estimator in terms of mean square error(MSE) and evaluate the system throughputs with different channel estimates over each scenario. Simulation results are then provided to corroborate our proposed studies. It is shown that our Hi BEM estimator outperforms other estimators and that the sys-展开更多
In this work,a frame work for time-varying channel modeling and simulation is proposed by using neural network(NN)to overcome the shortcomings in geometry based stochastic model(GBSM)and simulation approach.Two NN mod...In this work,a frame work for time-varying channel modeling and simulation is proposed by using neural network(NN)to overcome the shortcomings in geometry based stochastic model(GBSM)and simulation approach.Two NN models are developed for modeling of path loss together with shadow fading(SF)and joint small scale channel parameters.The NN models can predict path loss plus SF and small scale channel parameters accurately compared with measurement at 26 GHz performed in an outdoor microcell.The time-varying path loss and small scale channel parameters generated by the NN models are proposed to replace the empirical path loss and channel parameter random numbers in GBSM-based framework to playback the measured channel and match with its environment.Moreover,the sparse feature of clusters,delay and angular spread,channel capacity are investigated by a virtual array measurement at 28 GHz in a large waiting hall.展开更多
本文针对通信链路中存在近地多径、收发移动中的问题,构建了基于5G NR PDSCH信道链路模型,在高斯信道上对LS算法、LMMSE算法和基于DFT的LS信道估计算法等的信道估计对比分析,通过Matlab软件进行仿真。结果表明,在高斯信道上,LMMSE算法...本文针对通信链路中存在近地多径、收发移动中的问题,构建了基于5G NR PDSCH信道链路模型,在高斯信道上对LS算法、LMMSE算法和基于DFT的LS信道估计算法等的信道估计对比分析,通过Matlab软件进行仿真。结果表明,在高斯信道上,LMMSE算法信道估计效果最优,LS算法效果最差,基于DFT的LS算法效果介于前两者之间,且与降噪效果密切相关,降噪越好算法效果越接近LMMSE算法。展开更多
The growth of the wireless and mobile communication data traffic has brought severe challenges to the present telecommunication systems. To meet the ever-increasing mobile traffic demand in the next 5 th generation(5 ...The growth of the wireless and mobile communication data traffic has brought severe challenges to the present telecommunication systems. To meet the ever-increasing mobile traffic demand in the next 5 th generation(5 G) communication systems, deploying 5 G in the unlicensed spectrum(5 G-U), has been regarded as a promising technology. The Third Generation Partnership Project(3 GPP) has specified the standardization of the Licensed Assisted Access(LAA) and its extension enhanced LAA(e LAA), to opportunistically transmit in the unlicensed spectrum. The LAA/e LAA systems share unlicensed spectrum resource with other networks, e.g., the Wi-Fi systems. In this article, we analyze the coexistence between the e LAA and the Wi-Fi systems in the unlicensed spectrum. We firstly establish the system model where the e LAA coexists with the Wi-Fi systems. Then, we theoretically derive and figure out the unfairness in the multi-channel occupancy rate between the e LAA and the Wi-Fi systems. After that, we propose a weight based channel selection method to improve the fairness of the coexistence. The numerical results demonstrate that by avoiding contentions and declining collisions, our method not only enhances the fairness, but also improves the overall unlicensed spectrum usage rate.展开更多
为推进智能铁路总体建设,助力铁路数字化转型,基于5G的铁路专用移动通信系统(5G for Railway,5G-R)成为铁路智能联接的首选.作为最具发展潜力的B5G关键技术之一,智能超表面(Reconfigurable Intelligent Surface,RIS)具有复杂度低、成本...为推进智能铁路总体建设,助力铁路数字化转型,基于5G的铁路专用移动通信系统(5G for Railway,5G-R)成为铁路智能联接的首选.作为最具发展潜力的B5G关键技术之一,智能超表面(Reconfigurable Intelligent Surface,RIS)具有复杂度低、成本低和易于部署等优点,为5G智能高铁(High-Speed Railway,HSR)通信的发展提供了新契机.采用射线跟踪技术,精准刻画了2.1GHz频段下高铁高架桥场景的电波传播特性.基于准确的电波传播特性,利用发射机、反射面和接收机三者之间的角度关系,对RIS的部署位置和波束指向进行了设计.在获得RIS辅助下的信道传递函数后,对部署RIS前后的多维度信道特性进行了比较和研究.结果表明:引入RIS能够提升信号覆盖质量,加剧多径信号在时间域和空间域的色散程度,降低2T2R信道间的相关性,从而提高信道容量.本文研究成果可为高铁通信场景下5G-R系统与RIS的联合设计、优化提供理论指导和数据支撑.展开更多
在电力系统和能源互联网的深度融合大背景下,电力通信网融合第五代移动通信技术(fifth generation mobile communication technology,5G)成为一种必然趋势,5G电力通信网业务编排成为支撑电力业务服务质量需求的关键手段。针对电网中现...在电力系统和能源互联网的深度融合大背景下,电力通信网融合第五代移动通信技术(fifth generation mobile communication technology,5G)成为一种必然趋势,5G电力通信网业务编排成为支撑电力业务服务质量需求的关键手段。针对电网中现有业务编排优化存在的不足,提出了一种基于软件定义网络(software defined network,SDN)的5G电力通信网业务编排自主决策方法,利用Sarsa(state action reward state action)算法,通过不断与环境交互,在信息不确定的情况下实现接入网信道选择与核心网路由选择的联合优化,从而最小化电力通信终端数据包传输总时延,为电力业务超低时延需求提供保障。仿真结果表明,所提算法能够在传输环境突变的情况下,保持较低传输总时延,并降低波动,有效地提高了电力业务的传输质量。展开更多
While cellular networks have continuously evolved in re- cent years, the industry has clearly seen unprecedented chal- lenges to meet the exponentially growing expectations in the near future. The 5G system is facing ...While cellular networks have continuously evolved in re- cent years, the industry has clearly seen unprecedented chal- lenges to meet the exponentially growing expectations in the near future. The 5G system is facing grand challenges such as the ever-increasing traffic volumes and remarkably diver- sified services connecting humans and machines alike. As a result, the future network has to deliver massively increased capacity, greater flexibility, incorporated computing capabili- ty, support of significantly extended battery lifetime, and ac- commodation of varying payloads with fast setup and low latency, etc. In particular, as 5G requires more spectrum resource, higher frequency bands are desirable. Nowadays, millimeter wave has been widely accepted as one of the main communication bands for 5G.展开更多
While cellular networks have continuously evolved in recent years, the industry has clearly seen unprecedented challenges to meet the exponentially growing expectations in the near future.
基金supported by the National Natural Science Foundation of China(Grant Nos.61522109,61671253,61571037and 91738201)the Fundamental Research Funds for the Central Universities(No.2016JBZ006)+1 种基金the Natural Science Foundation of Jiangsu Province(Grant Nos.BK20150040and BK20171446)the Key Project of Natural Science Research of Higher Education Institutions of Jiangsu Province(No.15KJA510003)
文摘The fifth generation(5 G) wireless communication is currently a hot research topic and wireless communication systems on high speed railways(HSR) are important applications of 5 G technologies. Existing studies about 5 G wireless systems on high speed railways(HSR) often utilize ideal channel parameters and are usually based on simple scenarios. In this paper, we evaluate the downlink throughput of 5 G HSR communication systems on three typical scenarios including urban, cutting and viaduct with three different channel estimators. The channel parameters of each scenario are generated with tapped delay line(TDL) models through ray-tracing simulations, which can be considered as a good match to practical situations. The channel estimators including least square(LS), linear minimum mean square error(LMMSE), and our proposed historical information based basis expansion model(Hi BEM). We analyze the performance of the Hi BEM estimator in terms of mean square error(MSE) and evaluate the system throughputs with different channel estimates over each scenario. Simulation results are then provided to corroborate our proposed studies. It is shown that our Hi BEM estimator outperforms other estimators and that the sys-
基金supported by the National Nature Science Foundation of China(NSFC)under grant No.61771194supported by Key Program of Beijing Municipal Natural Science Foundation with No.17L20052
文摘In this work,a frame work for time-varying channel modeling and simulation is proposed by using neural network(NN)to overcome the shortcomings in geometry based stochastic model(GBSM)and simulation approach.Two NN models are developed for modeling of path loss together with shadow fading(SF)and joint small scale channel parameters.The NN models can predict path loss plus SF and small scale channel parameters accurately compared with measurement at 26 GHz performed in an outdoor microcell.The time-varying path loss and small scale channel parameters generated by the NN models are proposed to replace the empirical path loss and channel parameter random numbers in GBSM-based framework to playback the measured channel and match with its environment.Moreover,the sparse feature of clusters,delay and angular spread,channel capacity are investigated by a virtual array measurement at 28 GHz in a large waiting hall.
文摘本文针对通信链路中存在近地多径、收发移动中的问题,构建了基于5G NR PDSCH信道链路模型,在高斯信道上对LS算法、LMMSE算法和基于DFT的LS信道估计算法等的信道估计对比分析,通过Matlab软件进行仿真。结果表明,在高斯信道上,LMMSE算法信道估计效果最优,LS算法效果最差,基于DFT的LS算法效果介于前两者之间,且与降噪效果密切相关,降噪越好算法效果越接近LMMSE算法。
基金partly supported by the National Science and Technology Major Project(grant no.16510711600)the National Natural Science Foundation of China(grant no.61631013)partly supported by the National Natural Science Foundation of China(grant no.61401440)
文摘The growth of the wireless and mobile communication data traffic has brought severe challenges to the present telecommunication systems. To meet the ever-increasing mobile traffic demand in the next 5 th generation(5 G) communication systems, deploying 5 G in the unlicensed spectrum(5 G-U), has been regarded as a promising technology. The Third Generation Partnership Project(3 GPP) has specified the standardization of the Licensed Assisted Access(LAA) and its extension enhanced LAA(e LAA), to opportunistically transmit in the unlicensed spectrum. The LAA/e LAA systems share unlicensed spectrum resource with other networks, e.g., the Wi-Fi systems. In this article, we analyze the coexistence between the e LAA and the Wi-Fi systems in the unlicensed spectrum. We firstly establish the system model where the e LAA coexists with the Wi-Fi systems. Then, we theoretically derive and figure out the unfairness in the multi-channel occupancy rate between the e LAA and the Wi-Fi systems. After that, we propose a weight based channel selection method to improve the fairness of the coexistence. The numerical results demonstrate that by avoiding contentions and declining collisions, our method not only enhances the fairness, but also improves the overall unlicensed spectrum usage rate.
文摘在电力系统和能源互联网的深度融合大背景下,电力通信网融合第五代移动通信技术(fifth generation mobile communication technology,5G)成为一种必然趋势,5G电力通信网业务编排成为支撑电力业务服务质量需求的关键手段。针对电网中现有业务编排优化存在的不足,提出了一种基于软件定义网络(software defined network,SDN)的5G电力通信网业务编排自主决策方法,利用Sarsa(state action reward state action)算法,通过不断与环境交互,在信息不确定的情况下实现接入网信道选择与核心网路由选择的联合优化,从而最小化电力通信终端数据包传输总时延,为电力业务超低时延需求提供保障。仿真结果表明,所提算法能够在传输环境突变的情况下,保持较低传输总时延,并降低波动,有效地提高了电力业务的传输质量。
文摘While cellular networks have continuously evolved in re- cent years, the industry has clearly seen unprecedented chal- lenges to meet the exponentially growing expectations in the near future. The 5G system is facing grand challenges such as the ever-increasing traffic volumes and remarkably diver- sified services connecting humans and machines alike. As a result, the future network has to deliver massively increased capacity, greater flexibility, incorporated computing capabili- ty, support of significantly extended battery lifetime, and ac- commodation of varying payloads with fast setup and low latency, etc. In particular, as 5G requires more spectrum resource, higher frequency bands are desirable. Nowadays, millimeter wave has been widely accepted as one of the main communication bands for 5G.
文摘While cellular networks have continuously evolved in recent years, the industry has clearly seen unprecedented challenges to meet the exponentially growing expectations in the near future.
