随着物联网的兴起和移动互联网业务种类的日渐丰富,人们对蜂窝移动通信数据传输速率以及服务质量提出了更高的要求。由于能够充分挖掘空间维的自由度,在提高频谱效率的同时获得较好的功率利用率,大规模MIMO系统引起了国内外的广泛关注...随着物联网的兴起和移动互联网业务种类的日渐丰富,人们对蜂窝移动通信数据传输速率以及服务质量提出了更高的要求。由于能够充分挖掘空间维的自由度,在提高频谱效率的同时获得较好的功率利用率,大规模MIMO系统引起了国内外的广泛关注。大规模MIMO系统配置的大规模天线阵列在带来性能增益的同时也带来了前所未有的挑战,如大规模天线阵列系统下传输方案的设计、急剧增加的系统硬件复杂度和计算复杂度等。首先对大规模MIMO系统下的几种传输方案,如联合空分复用(JSDM)传输方案和大规模多波束空分多址(MB-SDMA)传输方案进行了概述,简略描述了不同传输方案的原理和传输过程,进一步简要介绍了目前正在构建的大规模MIMO原型验证系统Argos和Lu Ma Mi,并展示了不同原型验证系统的整体架构与组件。展开更多
In this paper,we introduce one full-duplex(FD) relaying transmission scheme for high speed railway and compare its ergodic capacity and outage performance with half-duplex(HD) relaying scheme. Both decode-and-forward(...In this paper,we introduce one full-duplex(FD) relaying transmission scheme for high speed railway and compare its ergodic capacity and outage performance with half-duplex(HD) relaying scheme. Both decode-and-forward(DF) amplify-and-forward(AF) relay modes are considered. Moreover,the carriage penetration loss(CPL) and the self-interference(SI) cancellation ratio are investigated. We derive the closed-form expressions for the outage probability and ergodic capacity of both HD and FD relay transmission schemes. It is shown that when CPL is larger than a certain level,the FD relay can achieve better performance in terms of capacity and keep the outage probability in a low level. It is also found that three factors: AF or DF modes,CPL and SI cancellation ratio,can have impact on capacity performance,and that CPL is one decisive factor. Our results can provide theoretical supports for development and deployment of future wireless communication systems on high speed railways.展开更多
In a three-dimensional （3D） multiple- input multiple-output （MIMO） system, the base station can use both horizontal and vertical spaces, transmitting spatial beam to users more accurately. This system has caught t...In a three-dimensional （3D） multiple- input multiple-output （MIMO） system, the base station can use both horizontal and vertical spaces, transmitting spatial beam to users more accurately. This system has caught the attention of researchers in recent years. The existing research on the 3D MIMO technology is based on the assumption that the base station can acquire the ideal channel state information （CSI）, which is not actually the case in real systems. Therefore, this paper introduces a limited feedback transmission scheme based on mobile station （MS） compensation in the 3D MIMO system. In this scheme, the vertical antenna gain of the 3D MIMO system compensation is assigned to the MS. Two CSI-RS ports are configured at the base station, omnidirectional CSI-RS port and partial CSI-RS port. The MS can calculate the horizontal CSI and the vertical beam gain according to omnidirectional CSI-RS port and partial CSI- RS port, respectively. Partial CSI-RS resources are used to calculate the channel after being weighted by the vertical beam vector, MS selects the optimal vertical precoding vector. Simulations show that compared with the reference strategy, the transmission scheme with limited feedback based on the MS compensation proposed in this article has more advantages. The average spectral efficiency of the system and the cell edge spectral efficiency can be greatly improved.展开更多
In orthogonal frequency division multiplexing(OFDM) systems,for given total transmit power,insertion of the noninformation bearing cyclic prefix(CP) will reduce the effective energy per information bit.Generally,the e...In orthogonal frequency division multiplexing(OFDM) systems,for given total transmit power,insertion of the noninformation bearing cyclic prefix(CP) will reduce the effective energy per information bit.Generally,the energy loss is proportional to the ratio of CP length to the symbol duration.If the CP is too long,the energy loss will be considerable high.In this paper,we propose an energy efficient transmission scheme for OFDM systems in Long Term Evolution(LTE) which is developed based on reduction of the CP energy.Simulation results show that the proposed method can save up to about10%of the total energy,while keeping almost the same bit-error-rate(BER) performance in some applications.展开更多
In cognitive relay networks, the transmission of Secondary Users （SUs） suffers from the activity of Primary Users （PUs） and wireless channel fading. Therefore, how to achieve robust transmission for cognitive rela...In cognitive relay networks, the transmission of Secondary Users （SUs） suffers from the activity of Primary Users （PUs） and wireless channel fading. Therefore, how to achieve robust transmission for cognitive relay networks is a challenging task. In this paper, we propose a relaying transmission scheme which exploits robust beamforming at the physical layer and rateless codes at higher layers. We derive the optirml beamforng weight vector and analyze the perforrmnce of the pro- posed scheme when the channel estirmtion is not accurate between two SU nodes. We also study how the anaount of channel information between SU and PU impacts the system perforroance. Sinlation results validate our theoretical analysis and demonstrate that the proposed scheme can signifi- cantly enhance the system throughput.展开更多
In this paper,an Interference Alignment and Cancellation(IAC)based transmission and scheduling scheme is proposed for an infrastructured Cognitive Radio(CR)Multiple-Input Multiple-Output(MIMO)system with multiple seco...In this paper,an Interference Alignment and Cancellation(IAC)based transmission and scheduling scheme is proposed for an infrastructured Cognitive Radio(CR)Multiple-Input Multiple-Output(MIMO)system with multiple secondary users.With the cooperation of Primary Base Station(PBS)and Secondary Base Station(SBS),a signal processing procedure is designed to guarantee the priority of the primary transmission.As a reward for offering help to the PBS,the SBS is granted communication opportunity.The transmission difference of various spatial channels is exploited in Secondary User(SU)scheduling.With the proposed scheme,interferencefree concurrent transmission of both PBS and SBS is implemented.Spatial channel resources can be effectively utilised compared with a traditional Interference Alignment(IA)based strategy.Simulation results show that the achievable data for primary transmission is enhanced by cooperative signal processing at the SBS.With respect to the SBS,its data rate grows with an increasing number of SUs by exploiting the multiuser diversity gain.展开更多
文摘随着物联网的兴起和移动互联网业务种类的日渐丰富,人们对蜂窝移动通信数据传输速率以及服务质量提出了更高的要求。由于能够充分挖掘空间维的自由度,在提高频谱效率的同时获得较好的功率利用率,大规模MIMO系统引起了国内外的广泛关注。大规模MIMO系统配置的大规模天线阵列在带来性能增益的同时也带来了前所未有的挑战,如大规模天线阵列系统下传输方案的设计、急剧增加的系统硬件复杂度和计算复杂度等。首先对大规模MIMO系统下的几种传输方案,如联合空分复用(JSDM)传输方案和大规模多波束空分多址(MB-SDMA)传输方案进行了概述,简略描述了不同传输方案的原理和传输过程,进一步简要介绍了目前正在构建的大规模MIMO原型验证系统Argos和Lu Ma Mi,并展示了不同原型验证系统的整体架构与组件。
基金supported by the National Natural Science Foundation of China(No.61571037)by the Fundamental Research Funds for the Central Universities(No.2016JBZ006)
文摘In this paper,we introduce one full-duplex(FD) relaying transmission scheme for high speed railway and compare its ergodic capacity and outage performance with half-duplex(HD) relaying scheme. Both decode-and-forward(DF) amplify-and-forward(AF) relay modes are considered. Moreover,the carriage penetration loss(CPL) and the self-interference(SI) cancellation ratio are investigated. We derive the closed-form expressions for the outage probability and ergodic capacity of both HD and FD relay transmission schemes. It is shown that when CPL is larger than a certain level,the FD relay can achieve better performance in terms of capacity and keep the outage probability in a low level. It is also found that three factors: AF or DF modes,CPL and SI cancellation ratio,can have impact on capacity performance,and that CPL is one decisive factor. Our results can provide theoretical supports for development and deployment of future wireless communication systems on high speed railways.
基金the National Natural Science Foundation of China Grants No.61302106,51274018,the National Science & Technology Pillar Program Grants No.2013BAK06B03 Natural Science Foundation of Hebei Province No.F2014502029 and the Fundamental Research Funds for the Central Universities Grants No.2014MS100
文摘In a three-dimensional （3D） multiple- input multiple-output （MIMO） system, the base station can use both horizontal and vertical spaces, transmitting spatial beam to users more accurately. This system has caught the attention of researchers in recent years. The existing research on the 3D MIMO technology is based on the assumption that the base station can acquire the ideal channel state information （CSI）, which is not actually the case in real systems. Therefore, this paper introduces a limited feedback transmission scheme based on mobile station （MS） compensation in the 3D MIMO system. In this scheme, the vertical antenna gain of the 3D MIMO system compensation is assigned to the MS. Two CSI-RS ports are configured at the base station, omnidirectional CSI-RS port and partial CSI-RS port. The MS can calculate the horizontal CSI and the vertical beam gain according to omnidirectional CSI-RS port and partial CSI- RS port, respectively. Partial CSI-RS resources are used to calculate the channel after being weighted by the vertical beam vector, MS selects the optimal vertical precoding vector. Simulations show that compared with the reference strategy, the transmission scheme with limited feedback based on the MS compensation proposed in this article has more advantages. The average spectral efficiency of the system and the cell edge spectral efficiency can be greatly improved.
基金the Chinese 863 Program，National "Eleventh Five-year" Project of China，the National Natural Science Foundation of China
文摘In orthogonal frequency division multiplexing(OFDM) systems,for given total transmit power,insertion of the noninformation bearing cyclic prefix(CP) will reduce the effective energy per information bit.Generally,the energy loss is proportional to the ratio of CP length to the symbol duration.If the CP is too long,the energy loss will be considerable high.In this paper,we propose an energy efficient transmission scheme for OFDM systems in Long Term Evolution(LTE) which is developed based on reduction of the CP energy.Simulation results show that the proposed method can save up to about10%of the total energy,while keeping almost the same bit-error-rate(BER) performance in some applications.
基金Acknowledgements The authors would like to thank the editor and anonymous reviewers for their detailed reviews and constructive comments, which have helped to greatly improve the quality of this paper. This work was supported by the National Natural Science Foundation of China under Grants No. 60832008, No. 60902001 Beijing Natural Science Foundation Program and Scientific Research Key Program of Beijing Municipal Commission of Education under Grant No. KZ201010009009 the Tsinghua National Laboratory for Infomation Science and Technology （TNList） Cross-discipline Foundation.
文摘In cognitive relay networks, the transmission of Secondary Users （SUs） suffers from the activity of Primary Users （PUs） and wireless channel fading. Therefore, how to achieve robust transmission for cognitive relay networks is a challenging task. In this paper, we propose a relaying transmission scheme which exploits robust beamforming at the physical layer and rateless codes at higher layers. We derive the optirml beamforng weight vector and analyze the perforrmnce of the pro- posed scheme when the channel estirmtion is not accurate between two SU nodes. We also study how the anaount of channel information between SU and PU impacts the system perforroance. Sinlation results validate our theoretical analysis and demonstrate that the proposed scheme can signifi- cantly enhance the system throughput.
基金supported by the National Natural Science Foundation of China under Grants No. 61102057,No. 61231008the National Key Basic Research Program of China (973 Program) under Grant No. 2009CB320404+4 种基金the National Science and Technology Major Project under Grant No. 2012ZX-03003005-005the 111 Project under Grant No.B08038the Program for Changjiang Scholars and Innovative Research Team in University under Grant No. IRT0852the ISN Project under Grant No. ISN1103005the Fundamental Research Funds for the Central Universities under Grant No. K5051301014
文摘In this paper,an Interference Alignment and Cancellation(IAC)based transmission and scheduling scheme is proposed for an infrastructured Cognitive Radio(CR)Multiple-Input Multiple-Output(MIMO)system with multiple secondary users.With the cooperation of Primary Base Station(PBS)and Secondary Base Station(SBS),a signal processing procedure is designed to guarantee the priority of the primary transmission.As a reward for offering help to the PBS,the SBS is granted communication opportunity.The transmission difference of various spatial channels is exploited in Secondary User(SU)scheduling.With the proposed scheme,interferencefree concurrent transmission of both PBS and SBS is implemented.Spatial channel resources can be effectively utilised compared with a traditional Interference Alignment(IA)based strategy.Simulation results show that the achievable data for primary transmission is enhanced by cooperative signal processing at the SBS.With respect to the SBS,its data rate grows with an increasing number of SUs by exploiting the multiuser diversity gain.
