该文对基于非实时信道状态信息(Channel State Information,CSI)的多用户放大转发(Amplify-and-Forward,AF)协作通信系统的性能进行分析。系统采用一点对多点的通信系统模型,中继节点根据过时的CSI选择用户。通过推导得出中断概率、信...该文对基于非实时信道状态信息(Channel State Information,CSI)的多用户放大转发(Amplify-and-Forward,AF)协作通信系统的性能进行分析。系统采用一点对多点的通信系统模型,中继节点根据过时的CSI选择用户。通过推导得出中断概率、信道容量和符号错误概率(Symbol Error Rate,SER)的近似表达式。理论分析适用于链路同分布或者非同分布。仿真结果验证理论的正确性,并说明了各种参数对系统性能的影响。同时指出,增加用户数并不能提高系统性能,性能的提高可以通过改变中继的位置来实现。展开更多
This paper explores the potential to use accurate but outdated channel estimates for adaptive modulation. The work is novel in that the research is conditioned on block by block adaptation. First,we define a new quant...This paper explores the potential to use accurate but outdated channel estimates for adaptive modulation. The work is novel in that the research is conditioned on block by block adaptation. First,we define a new quantity,the Tolerable Average Use Delay (TAUD),which can indicate the ability of an adaptation scheme to tolerate the delay of channel estimation results. We find that for the variable-power schemes,TAUD is a constant and dependent on the target Bit Error Rate (BER),average power and Doppler frequency; while for the constant-power schemes,it depends on the ad-aptation block length as well. At last,we investigate the relation between the delay tolerating per-formance and the spectral efficiency and give the system design criterion. The delay tolerating per-formance is improved at the price of lower data rate.展开更多
首先定义了过时信道状态信息(OCSI,Outdated Channel State Information)对系统频谱效率的影响因子,分析了OCSI对频谱效率的影响;接着提出了一种基于信噪比预测的无线链路自适应系统模型,应用文中提出的基于信道变化场景的信噪比预测算...首先定义了过时信道状态信息(OCSI,Outdated Channel State Information)对系统频谱效率的影响因子,分析了OCSI对频谱效率的影响;接着提出了一种基于信噪比预测的无线链路自适应系统模型,应用文中提出的基于信道变化场景的信噪比预测算法(SSPA,Scenario-based SNR Prediction Algorithm)对发送数据时的信噪比进行预测,以克服OCSI的影响。仿真表明,与现有技术比较,基于SSPA的自适应系统具有近似的误比特率性能,频谱效率得到了有效的提升,特别是在高信噪比区域,频谱效率的改善十分显著。展开更多
文摘该文对基于非实时信道状态信息(Channel State Information,CSI)的多用户放大转发(Amplify-and-Forward,AF)协作通信系统的性能进行分析。系统采用一点对多点的通信系统模型,中继节点根据过时的CSI选择用户。通过推导得出中断概率、信道容量和符号错误概率(Symbol Error Rate,SER)的近似表达式。理论分析适用于链路同分布或者非同分布。仿真结果验证理论的正确性,并说明了各种参数对系统性能的影响。同时指出,增加用户数并不能提高系统性能,性能的提高可以通过改变中继的位置来实现。
基金Supported by the National Natural Science Foundation of China (No.60496311).
文摘This paper explores the potential to use accurate but outdated channel estimates for adaptive modulation. The work is novel in that the research is conditioned on block by block adaptation. First,we define a new quantity,the Tolerable Average Use Delay (TAUD),which can indicate the ability of an adaptation scheme to tolerate the delay of channel estimation results. We find that for the variable-power schemes,TAUD is a constant and dependent on the target Bit Error Rate (BER),average power and Doppler frequency; while for the constant-power schemes,it depends on the ad-aptation block length as well. At last,we investigate the relation between the delay tolerating per-formance and the spectral efficiency and give the system design criterion. The delay tolerating per-formance is improved at the price of lower data rate.
