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Performance of Adaptive Subchannel Assignment-Based MIMO/OFDM Systems over Multipath Fading Channels
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作者 潘亚汉 Khaled Ben Letaief 曹志刚 《Tsinghua Science and Technology》 SCIE EI CAS 2006年第1期19-24,共6页
Adaptive antenna arrays at both the base and mobile stations can further increase system capacity and improve the quality of service of conventional orthogonal frequency division multiplexing (OFDM) systems. Convent... Adaptive antenna arrays at both the base and mobile stations can further increase system capacity and improve the quality of service of conventional orthogonal frequency division multiplexing (OFDM) systems. Conventional adaptive antenna array-based multiple-input multiple-output (MIMO)/OFDM systems use the sub-carriers characterized by the largest eigenvalue to transmit the OFDM symbols. This paper describes the performance of adaptive subchannel assignment-based MIMO/OFDM systems over multipath fading channels, The system adaptively selects the eigenvectors associated with the relatively large subchannel eigenvalues to generate the antenna array weights at the base and mobile stations and then adaptively assigns the corresponding best subchannels to transmit the OFDM symbols. Simulation results show that the proposed system can achieve better performance than the conventional adaptive antenna arraybased MIMO/OFDM system over multipath fading channels. 展开更多
关键词 multiple-input multiple-output mimo)/orthogonal frequency division multiplexing (OFDM) adaptive subchannel assignment joint transmit and receive antenna array weighting multipath fading channel
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MIMO-OFDM同步门限值方法 被引量:1
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作者 陈威 伍仁勇 杨智明 《信号处理》 CSCD 北大核心 2012年第9期1290-1298,共9页
正交频分复用(OFDM)技术由于其对抗多径能力强和频谱利用率高而被视为下一代无线通信的核心技术,多输入多输出天线系统(MIMO)利用空间复用进一步提高频谱效率。二者已经应用于多种高速宽带通信系统中。MIMO-OFDM与SISO-OFDM相似,对定时... 正交频分复用(OFDM)技术由于其对抗多径能力强和频谱利用率高而被视为下一代无线通信的核心技术,多输入多输出天线系统(MIMO)利用空间复用进一步提高频谱效率。二者已经应用于多种高速宽带通信系统中。MIMO-OFDM与SISO-OFDM相似,对定时同步错误和频率偏移敏感。任何不同步都可能会破坏接收帧结构,因此准确的符号定时同步和精确的载波频偏估计是系统可靠工作的前提。本文中首先用CAZAC序列构建出共轭交错结构作为训练序列,然后应用门限值方法改进定时同步估计,并基于这种交错结构进行载波频率偏移估计,确定影响门限值性能的参数值。仿真数据显示,在多径信道条件下,该方法可以使系统的误码率相对传统方法得到进一步减小,有效提高系统同步性能。 展开更多
关键词 多输入输出 正交频分复用 频率偏移 定时同步 门限
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针对非格点参数的双基地MIMO雷达联合稀疏恢复
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作者 袁湘辉 张云雷 刘雅琦 《科学技术与工程》 北大核心 2017年第25期251-255,共5页
将稀疏恢复应用于雷达参数估计中,在保证估计精度同时,可大幅减少空时采样个数;但当目标参数不在格点时,估计误差会明显恶化。针对双基地MIMO雷达中不在格点的参数估计问题,引入联合稀疏优化方法,构建结构化误差矩阵和块稀疏向量。推导... 将稀疏恢复应用于雷达参数估计中,在保证估计精度同时,可大幅减少空时采样个数;但当目标参数不在格点时,估计误差会明显恶化。针对双基地MIMO雷达中不在格点的参数估计问题,引入联合稀疏优化方法,构建结构化误差矩阵和块稀疏向量。推导了进行参数估计的修正表达式,然后利用块稀疏算法求解,可有效提高稀疏恢复的精度。为解决计算复杂性,引入快速KCS稀疏恢复算法。仿真表明,在典型恢复场景下,可明显提高参数估计精度;同时计算时间节省1个数量级以上。 展开更多
关键词 非格点 联合稀疏恢复 双基地mimo雷达 块正交匹配跟踪
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Hardware Implementation and Simulations of Joint Coding and Modulation Diversity MIMO-OFDM Scheme 被引量:4
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作者 Xiang Gao Zhan-Ji Wu +1 位作者 Long-Fei Hua Jun-Peng Liu 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2013年第3期27-34,共8页
This paper presents an efficient Joint Coding and Modulation Diversity ( JCMD ) scheme. The proposed scheme applied modulation diversity technique to MIMO-OFDM system which can effectively use time, frequency and spac... This paper presents an efficient Joint Coding and Modulation Diversity ( JCMD ) scheme. The proposed scheme applied modulation diversity technique to MIMO-OFDM system which can effectively use time, frequency and space diversity combined with channel coding. In fading channel,the proposed scheme not only achieves high spectral efficiency,but also greatly enhances the reliability of wireless transmission. The self- developed hardware prototype system proves that the proposed scheme can be realized and has high reliability. Compared with traditional MIMO-OFDM scheme based on bit-interleaved coded modulation ( BICM) ,software and hardware simulation results show that the proposed scheme with the optimal rotational angle can obtain a significant performance advantage both for precoded and non-precoded system in the condition of non-perfect channel knowledge and non-ideal synchronization. 展开更多
关键词 multiple input multiple output ( mimo) orthogonal frequency division multiplexing ( OFDM) modulation diversity channel estimation
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