在单载波频分多址接入(single carrier frequency division multiple access,SC-FDMA)系统中提出用Ⅰ型、Ⅱ型、Ⅲ型、Ⅳ型4种不同类型离散余弦变换代替离散傅里叶变换。基于不同变换,分别推导上行链路传输信号时域表达式,并对推导式展...在单载波频分多址接入(single carrier frequency division multiple access,SC-FDMA)系统中提出用Ⅰ型、Ⅱ型、Ⅲ型、Ⅳ型4种不同类型离散余弦变换代替离散傅里叶变换。基于不同变换,分别推导上行链路传输信号时域表达式,并对推导式展开分析,比较基于不同类型离散余弦变换的SC-FDMA系统信号的特性及PAPR(peak to av-erage power ratio)性能。仿真结果表明基于DCT-Ⅱ的SC-FDMA系统与基于DFT(discrete Fourier transform)的系统一致,具有更好的PAPR特性。展开更多
为有效利用非理想信道状态信息(imperfect channel state information,ICSI)进行自适应资源调度以提高链路平均有效吞吐量,给出了采用M-QAM调制方式时ICSI下用户平均成功传输速率公式,通过仿真验证了其正确性,并据该公式提出一种基于ICS...为有效利用非理想信道状态信息(imperfect channel state information,ICSI)进行自适应资源调度以提高链路平均有效吞吐量,给出了采用M-QAM调制方式时ICSI下用户平均成功传输速率公式,通过仿真验证了其正确性,并据该公式提出一种基于ICSI的自适应调制方案。通过分别研究ICSI对自适应子载波分配和自适应调制的影响,分析ICSI可靠度对链路平均有效吞吐量的影响。仿真结果表明,基于ICSI的自适应调制方案可有效对抗ICSI可靠度下降对平均有效吞吐量的影响;相比之下,采用自适应子载波分配算法时,ICSI可靠度的下降对链路平均有效吞吐量的影响较大。展开更多
This article proposes a new transceiver design for Single carrier frequency division multiple access(SCFDMA)system based on discrete wavelet transform(DWT). SCFDMA offers almost same structure as Orthogonal frequency ...This article proposes a new transceiver design for Single carrier frequency division multiple access(SCFDMA)system based on discrete wavelet transform(DWT). SCFDMA offers almost same structure as Orthogonal frequency division multiple access(OFDMA)with extra advantage of low Peak to Average Power Ratio(PAPR). Moreover,this article also suggests the application of Walsh Hadamard transform(WHT)for linear precoding(LP)to improve the PAPR performance of the system. Supremacy of the proposed transceiver over conventional Fast Fourier transform(FFT)based SCFDMA is shown through simulated results in terms of PAPR,spectral efficiency(SE)and bit error rate(BER).展开更多
为了提高单载波频分多址接入(SC-FDMA)系统的性能,一种简单且有效的基于探测参考信号(SRS)的噪声估计算法是必要的。针对传统基于离散傅里叶变换(DFT)算法的缺陷,提出了一种改进的基于DFT的算法。另外,在该改进的基于DFT的算法的基础上...为了提高单载波频分多址接入(SC-FDMA)系统的性能,一种简单且有效的基于探测参考信号(SRS)的噪声估计算法是必要的。针对传统基于离散傅里叶变换(DFT)算法的缺陷,提出了一种改进的基于DFT的算法。另外,在该改进的基于DFT的算法的基础上,又通过增加汉宁窗进行修正,减小了高信噪比下信号能量的泄露。仿真结果表明,在低信噪比下,改进的基于DFT的算法的性能相比传统的算法性能上有4 d B的改善。但是,在高信噪比下,改进的基于DFT的算法的性能逐渐变差,而通过添加汉宁窗却能修正这一缺陷,使其性能得到至少4 d B的改善。展开更多
Two utility-optimization dynamic subcarrier allocation(DSA) algorithms are designed for single carrier frequency division multiple access system(SC-FDMA).The two proposed algorithms aim to support diverse transmission...Two utility-optimization dynamic subcarrier allocation(DSA) algorithms are designed for single carrier frequency division multiple access system(SC-FDMA).The two proposed algorithms aim to support diverse transmission capacity requirements in wireless networks,which consider both the channel state information(CSI) and the capacity requirements of each user by setting appropriate utility functions.Simulation results show that with considerable lower computational complexity,the first utility-optimization algorithm can meet the system capacity requirements of each user effectively.However,the rate-sum capacity performance is poor.Furthermore,the second proposed utility-optimization algorithm can contribute a better trade-off between system rate-sum capacity requirement and the capacity requirements of each user by introducing the signal to noise ratio(SNR) information to the utility function based on the first utility-optimization algorithm,which can improve the user requirements processing capability as well as achieve a better sum-rate capacity.展开更多
文摘在单载波频分多址接入(single carrier frequency division multiple access,SC-FDMA)系统中提出用Ⅰ型、Ⅱ型、Ⅲ型、Ⅳ型4种不同类型离散余弦变换代替离散傅里叶变换。基于不同变换,分别推导上行链路传输信号时域表达式,并对推导式展开分析,比较基于不同类型离散余弦变换的SC-FDMA系统信号的特性及PAPR(peak to av-erage power ratio)性能。仿真结果表明基于DCT-Ⅱ的SC-FDMA系统与基于DFT(discrete Fourier transform)的系统一致,具有更好的PAPR特性。
文摘为有效利用非理想信道状态信息(imperfect channel state information,ICSI)进行自适应资源调度以提高链路平均有效吞吐量,给出了采用M-QAM调制方式时ICSI下用户平均成功传输速率公式,通过仿真验证了其正确性,并据该公式提出一种基于ICSI的自适应调制方案。通过分别研究ICSI对自适应子载波分配和自适应调制的影响,分析ICSI可靠度对链路平均有效吞吐量的影响。仿真结果表明,基于ICSI的自适应调制方案可有效对抗ICSI可靠度下降对平均有效吞吐量的影响;相比之下,采用自适应子载波分配算法时,ICSI可靠度的下降对链路平均有效吞吐量的影响较大。
文摘This article proposes a new transceiver design for Single carrier frequency division multiple access(SCFDMA)system based on discrete wavelet transform(DWT). SCFDMA offers almost same structure as Orthogonal frequency division multiple access(OFDMA)with extra advantage of low Peak to Average Power Ratio(PAPR). Moreover,this article also suggests the application of Walsh Hadamard transform(WHT)for linear precoding(LP)to improve the PAPR performance of the system. Supremacy of the proposed transceiver over conventional Fast Fourier transform(FFT)based SCFDMA is shown through simulated results in terms of PAPR,spectral efficiency(SE)and bit error rate(BER).
文摘为了提高单载波频分多址接入(SC-FDMA)系统的性能,一种简单且有效的基于探测参考信号(SRS)的噪声估计算法是必要的。针对传统基于离散傅里叶变换(DFT)算法的缺陷,提出了一种改进的基于DFT的算法。另外,在该改进的基于DFT的算法的基础上,又通过增加汉宁窗进行修正,减小了高信噪比下信号能量的泄露。仿真结果表明,在低信噪比下,改进的基于DFT的算法的性能相比传统的算法性能上有4 d B的改善。但是,在高信噪比下,改进的基于DFT的算法的性能逐渐变差,而通过添加汉宁窗却能修正这一缺陷,使其性能得到至少4 d B的改善。
基金Supported by the National Basic Research Program of China(No.61393010101-1)the Defense-related Science & Technology Pre-Research Project of Shipbuilding Institute(No.10J3.1.6)
文摘Two utility-optimization dynamic subcarrier allocation(DSA) algorithms are designed for single carrier frequency division multiple access system(SC-FDMA).The two proposed algorithms aim to support diverse transmission capacity requirements in wireless networks,which consider both the channel state information(CSI) and the capacity requirements of each user by setting appropriate utility functions.Simulation results show that with considerable lower computational complexity,the first utility-optimization algorithm can meet the system capacity requirements of each user effectively.However,the rate-sum capacity performance is poor.Furthermore,the second proposed utility-optimization algorithm can contribute a better trade-off between system rate-sum capacity requirement and the capacity requirements of each user by introducing the signal to noise ratio(SNR) information to the utility function based on the first utility-optimization algorithm,which can improve the user requirements processing capability as well as achieve a better sum-rate capacity.
