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一种用于下行传输的特征波束发射分集方案 被引量:1
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作者 李勇朝 廖桂生 王峰 《系统工程与电子技术》 EI CSCD 北大核心 2005年第3期395-398,共4页
发射分集要求不同发射天线的信道衰落是相互独立的,而作为智能天线核心技术之一的特征波束形成则需要利用发射天线之间的相关性来实现,它可以将衰落相关信道转换为相互独立的衰落信道。将发射分集技术和特征波束形成技术相结合,研究了... 发射分集要求不同发射天线的信道衰落是相互独立的,而作为智能天线核心技术之一的特征波束形成则需要利用发射天线之间的相关性来实现,它可以将衰落相关信道转换为相互独立的衰落信道。将发射分集技术和特征波束形成技术相结合,研究了一种用于下行传输衰落相关信道的发射分集实现方案。利用空域协方差矩阵的特征矢量作为空时码矩阵的加权因子,即利用相互正交的特征波束来承载空时码。载有空时码的特征波束可以选择空间能量最集中的方向发射信息,从而提高了发射分集在衰落相关信道中的传输性能,降低了系统实现的复杂度。 展开更多
关键词 特征波束形成 发射分集 下行传输
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Spacetime coded eigenbeamforming for downlink frequency-selective correlated fading channels
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作者 李勇朝 廖桂生 仝文宁 《Journal of Shanghai University(English Edition)》 CAS 2006年第6期500-505,共6页
To improve the performance of space-time coding over downlink frequency-selective correlated fading channels, a novel transmission scheme combining eigenbeamfoming and OFDM is proposed. Provided that the channel corre... To improve the performance of space-time coding over downlink frequency-selective correlated fading channels, a novel transmission scheme combining eigenbeamfoming and OFDM is proposed. Provided that the channel correlated statistics are available at the transmitter, the wideband correlated fading channels can be converted into an independent FIR channel with 2 transmitting antennas and N receiving antennas by eigenbeamforming and dimension reduction. OFDM is utilized to convert the FIR channel into a group of independent parallel subchanneis to carry space-time codes. With the new structure, the performance of space-time coding over downlink wideband correlated fading channels is greatly improved and the system complexity is reduced. Validity of the proposed system is verified by simulations under different conditions. Comparison between the new structure and an available structure is made both theoretically and computationslly. 展开更多
关键词 frequency-selective correlated fading OFDM space-time coded eigenbeamforming.
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Closed Loop Space-Time Block Coding for Wireless Downlink Transmission
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作者 李勇朝 廖桂生 王峰 《Journal of Southwest Jiaotong University(English Edition)》 2005年第1期18-22,共5页
In order to improve the poor performance of Space-Time Block Coding (STBC) in a downlink correlated fading environment, a closed loop scheme is proposed. With the known channel fading statistics fed from the receiver,... In order to improve the poor performance of Space-Time Block Coding (STBC) in a downlink correlated fading environment, a closed loop scheme is proposed. With the known channel fading statistics fed from the receiver, eigenbeamforming is utilized to improve the performance of STBC at the transmitter. The new system achieves the array and diversity gain simultaneously. Because reduced dimension processing is adopted, the proposed system has a relative simple structure compared with the traditional beamforming system. The validity of the scheme is verified in several situations by simulation experiments. 展开更多
关键词 Space-time block coding eigenbeamforming Downlink transmission
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