单载波频分多址(Single-Carrier Frequency Division Multiple Access,SC-FDMA)系统均衡器的输入信号通常是按符号间隔进行采样的,其对抽样时间十分敏感.在短波波段,由于多径反射显著,当多径延时接近符号周期长度时,对抽样时间敏感的缺点会被放大.针对短波信道的特征,研究了 SC-FDMA系统的分数间隔均衡器(Fractional Spaced Equalizer,FSE)模型,通过与符号间隔均衡器对比发现,虽然符号间隔均衡器可以补偿接收信号的频率响应,但其对短时延衰落信道的补偿效果较差;FSE对于抽样时间的选择不敏感,在多径信道下能够获得更好的性能.链路仿真结果表明,在短时衰落信道环境下,FSE的译码性能比符号间隔均衡器有最大1.5 dB的增益.
Abstract
The input signal of a Single-Carrier Frequency Division Multiple Access(SC-FDMA)system equalizer is generally sampled at symbolic intervals,and the symbol spaced equalizer is sensitive to the sampling time.In the shortwave band,due to strong multi-path reflection,the shortcomings of being sensitive to the sampling time are magnified when the multi-path delay is close to the length of symbol period.According to the characteristics of the shortwave channel,the Fractional Spaced Equalizer(FSE)model of the SC-FDMA system is analyzed.By comparing FSE with the symbol spaced equalizer,it is found that although the symbol spaced equalizer can make up for the frequency response of the received signal,its compensation effect is still not good for short-delay fading channels,while FSE is insensitive to the selection of sampling time,which can achieve better performance in multipath channels.The link simulation results show that,in the short-term fading channel environment,FSE can improve the decoding performance by 1.5 dB compared to the symbol interval equalizer.
关键词
无线通信/多径信道/单载波频分多址/分数间隔均衡器/最小均方误差
Key words
wireless communication/multi-path channel/SC-FDMA/FSE/minimum mean square error
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