频率选择性信道下的多天线信号分量合成算法

信道的多径效应和噪声会严重地影响信号的通信质量，可以通过空间分集技术提高信噪比和降低多径的影响。针对频率选择性信道下的多天线信号合成问题，给出了一种在未知信道下无需进行符号同步的多天线信号分量合成算法。在频域，该算法按照每频点信噪比最大化准则对信号进行加权合成，提高合成输出信号的每个频点信噪比，降低合成信号的衰弱特性。另外，分析了采用FFT实现时的相关问题，并利用常用的QPSK和16QAM信号进行仿真验证，最后对合成前后的信号进行解调。结果表明该算法能够有效地提高信号的接收质量，无需信号的定时同步和载波同步，对信号调制方式透明，为频率选择性信道下的低信噪比信号合成提供了新的解决思路，具有较强的实用价值。

Signal Components Combination Algorithm on a Multi-Antennas Array for Frequency Selective Channels

The communication quality can be deteriorated seriously by the multi-path channel and the additive noise, and those adverse effects can be reduced by spatial diversity using an antenna array. An effective blind combination algorithm is proposed to combine the low SNR signals from multiple antennas array without signal timing synchronization for frequency selective channels. By this algo- rithm, signals are combined with weighted addition following the principle that the SNR at each frequency point is maximized. The combined signal distortion is reduced, with improved SNR. This paper also analyzes Fast Fourier Transform （FFT） implementations issues and verifies this algorithm validity with QPSK and 16QAM signals. Simulation results indicate that this algorithm can improve performance significantly, and doesnt require signal timing synchronization and carrier synchronization. Since this algorithm is transparent to signal modulation, a novel approach is offered for low- SNR signals combination in frequency selective channels.