为了对先进的长期演进技术(long term evolution-advanced,LTE-Advanced)系统中的多输入多输出(multipleinput and multiple output,MIMO)技术的性能进行评估,简单回顾了LTE-Advanced系统中的2种MIMO技术,即空间复用和空间分集,并介绍...为了对先进的长期演进技术(long term evolution-advanced,LTE-Advanced)系统中的多输入多输出(multipleinput and multiple output,MIMO)技术的性能进行评估,简单回顾了LTE-Advanced系统中的2种MIMO技术,即空间复用和空间分集,并介绍了一种适合LTE-Advanced系统评估的信道模型-IMT-Advanced(international mobile tele-communications-advanced)信道模型。基于该信道模型,通过系统仿真对以上2种关键MIMO技术进行了性能评估。仿真结果表明,不同的MIMO技术、调制方式、码本、复用率及接收方案都对性能有极大的影响。展开更多
先进的长期演进技术(long term evolution advanced,LTE-advanced)是新一代无线移动通信系统核心技术,如何有效评估这一技术系统性能是当前研究重点之一。在充分理解无线通信系统级仿真基本理论和LTE-advanced系统级仿真若干规范基础上...先进的长期演进技术(long term evolution advanced,LTE-advanced)是新一代无线移动通信系统核心技术,如何有效评估这一技术系统性能是当前研究重点之一。在充分理解无线通信系统级仿真基本理论和LTE-advanced系统级仿真若干规范基础上,梳理LTE-advanced系统级仿真涉及的组织结构,采用模块化设计方法,以此结构为框架搭建系统级仿真平台,实现对LTE-advanced进行系统级仿真。进一步以LTE-advanced系统重要性能参数平均吞吐量为考察指标,重点分析对比了轮询、最大载干比、比例公平这3种调度算法对LTE-advanced网络整体性能的影响。展开更多
The energy efficiency and packet delay tradeoffs in long term evolution-advanced(LTE-A) systems are investigated.Analytical expressions are derived to explain the relation of energy efficiency to mean packet delay,arr...The energy efficiency and packet delay tradeoffs in long term evolution-advanced(LTE-A) systems are investigated.Analytical expressions are derived to explain the relation of energy efficiency to mean packet delay,arrival rate and component carrier(CC) configurations,from the theoretical respective which reveals that the energy efficiency of multiple CC systems is closely related to the frequency of CCs and the number of active CCs.Based on the theoretical analysis,a CC adjusting scheme for LTE-A systems is proposed to maximize energy efficiency subject to delay constraint by dynamically altering the on/off state of CCs according to traffic variations.Numerical and simulation results show that for CCs in different frequency bands with equal transmit power,the proposed scheme could significantly improve the energy efficiency of users in all aggregation levels within the constraint of mean packet delay.展开更多
根据多普勒频移对物理随机接入信道(PRACH)信号检测产生的影响进行分析,划分出了中速、高速、超高速三种模式,并提出相应改进的信号检测算法。对中速模式,提出了基于频偏校正的前导检测算法;对高速模式,提出了多重滑窗峰值检测算法;对...根据多普勒频移对物理随机接入信道(PRACH)信号检测产生的影响进行分析,划分出了中速、高速、超高速三种模式,并提出相应改进的信号检测算法。对中速模式,提出了基于频偏校正的前导检测算法;对高速模式,提出了多重滑窗峰值检测算法;对超高速模式,提出了基于整数倍子载波的频偏补偿前导检测算法。仿真结果表明,不同场景下PRACH信号通过加性高斯白噪声(AWGN)信道传输,接收端虚警率性能至少改善了3.8 d B;通过扩展典型城市信道模型(ETU)信道传输,虚警率性能至少提升了1 d B。与频域相关检测算法相比,所提算法提高了前导信号成功检测概率,减少了接入时延。展开更多
以Long Term Evolution-Advanced(LTE-A)系统中宏蜂窝-微蜂窝(Macro-Pico)异构多层网络为例,以范围扩展(Range Extension,RE)技术为基础,提出了一种移动负载均衡算法。建立了网络负载模型,计算并选取合适的小区切换偏移量,从而动态精确...以Long Term Evolution-Advanced(LTE-A)系统中宏蜂窝-微蜂窝(Macro-Pico)异构多层网络为例,以范围扩展(Range Extension,RE)技术为基础,提出了一种移动负载均衡算法。建立了网络负载模型,计算并选取合适的小区切换偏移量,从而动态精确的调整超载小区和轻负载小区的覆盖范围,最终将超载小区的多余用户切换到其轻负载的邻小区,并结合数据流量业务对算法进行了仿真,分析了在该算法的协作下,小区的负载均衡因子、负载转移率及用户满意率,验证了该算法的可行性。展开更多
This paper presents a novel way to improve Transmission Control Protocol (TCP) performance of the users at the edge areas of the macro cells in Long Term Evolution Advanced (LTE-A) systems. Previous works on improving...This paper presents a novel way to improve Transmission Control Protocol (TCP) performance of the users at the edge areas of the macro cells in Long Term Evolution Advanced (LTE-A) systems. Previous works on improving wireless TCP performance are reviewed and current considerations on TCP in LTE-A are explained. However, those solutions are neither too complex nor limited to some presuppositions which are too restricting for the deployment of LTE-A networks. In this paper a substituted TCP acknowledgement transmission scheme based on Automatic Repeat reQuest (ARQ) information in layer 2 is proposed. The simulation result shows that the proposed method can reduce the delay and improve the throughput of the edging users of the cell, as well as reducing radio resources in LTE-A macro cells.展开更多
文摘为了对先进的长期演进技术(long term evolution-advanced,LTE-Advanced)系统中的多输入多输出(multipleinput and multiple output,MIMO)技术的性能进行评估,简单回顾了LTE-Advanced系统中的2种MIMO技术,即空间复用和空间分集,并介绍了一种适合LTE-Advanced系统评估的信道模型-IMT-Advanced(international mobile tele-communications-advanced)信道模型。基于该信道模型,通过系统仿真对以上2种关键MIMO技术进行了性能评估。仿真结果表明,不同的MIMO技术、调制方式、码本、复用率及接收方案都对性能有极大的影响。
文摘先进的长期演进技术(long term evolution advanced,LTE-advanced)是新一代无线移动通信系统核心技术,如何有效评估这一技术系统性能是当前研究重点之一。在充分理解无线通信系统级仿真基本理论和LTE-advanced系统级仿真若干规范基础上,梳理LTE-advanced系统级仿真涉及的组织结构,采用模块化设计方法,以此结构为框架搭建系统级仿真平台,实现对LTE-advanced进行系统级仿真。进一步以LTE-advanced系统重要性能参数平均吞吐量为考察指标,重点分析对比了轮询、最大载干比、比例公平这3种调度算法对LTE-advanced网络整体性能的影响。
基金Supported by the National High Technology Research and Development Program of China(No.2011AA01A109)the National Natural Science Foundation of China(No.61002017,61072076.)the Department of Science and Technology Commission of Shanghai Base Project(No.11DZ2290100)
文摘The energy efficiency and packet delay tradeoffs in long term evolution-advanced(LTE-A) systems are investigated.Analytical expressions are derived to explain the relation of energy efficiency to mean packet delay,arrival rate and component carrier(CC) configurations,from the theoretical respective which reveals that the energy efficiency of multiple CC systems is closely related to the frequency of CCs and the number of active CCs.Based on the theoretical analysis,a CC adjusting scheme for LTE-A systems is proposed to maximize energy efficiency subject to delay constraint by dynamically altering the on/off state of CCs according to traffic variations.Numerical and simulation results show that for CCs in different frequency bands with equal transmit power,the proposed scheme could significantly improve the energy efficiency of users in all aggregation levels within the constraint of mean packet delay.
文摘根据多普勒频移对物理随机接入信道(PRACH)信号检测产生的影响进行分析,划分出了中速、高速、超高速三种模式,并提出相应改进的信号检测算法。对中速模式,提出了基于频偏校正的前导检测算法;对高速模式,提出了多重滑窗峰值检测算法;对超高速模式,提出了基于整数倍子载波的频偏补偿前导检测算法。仿真结果表明,不同场景下PRACH信号通过加性高斯白噪声(AWGN)信道传输,接收端虚警率性能至少改善了3.8 d B;通过扩展典型城市信道模型(ETU)信道传输,虚警率性能至少提升了1 d B。与频域相关检测算法相比,所提算法提高了前导信号成功检测概率,减少了接入时延。
文摘以Long Term Evolution-Advanced(LTE-A)系统中宏蜂窝-微蜂窝(Macro-Pico)异构多层网络为例,以范围扩展(Range Extension,RE)技术为基础,提出了一种移动负载均衡算法。建立了网络负载模型,计算并选取合适的小区切换偏移量,从而动态精确的调整超载小区和轻负载小区的覆盖范围,最终将超载小区的多余用户切换到其轻负载的邻小区,并结合数据流量业务对算法进行了仿真,分析了在该算法的协作下,小区的负载均衡因子、负载转移率及用户满意率,验证了该算法的可行性。
基金Partly supported by the Key Project of National Natural Science Foundation of China(No.61231007)863 Hi Tech R&D Program of China(No.2012AA121604)ISTCP(No.2012DFG12010)
文摘This paper presents a novel way to improve Transmission Control Protocol (TCP) performance of the users at the edge areas of the macro cells in Long Term Evolution Advanced (LTE-A) systems. Previous works on improving wireless TCP performance are reviewed and current considerations on TCP in LTE-A are explained. However, those solutions are neither too complex nor limited to some presuppositions which are too restricting for the deployment of LTE-A networks. In this paper a substituted TCP acknowledgement transmission scheme based on Automatic Repeat reQuest (ARQ) information in layer 2 is proposed. The simulation result shows that the proposed method can reduce the delay and improve the throughput of the edging users of the cell, as well as reducing radio resources in LTE-A macro cells.