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针对对抗无线信道多径衰落的正交频分复用(orthogonal frequency division multiplexing,OFDM)系统,本文提出了一种联合时域和频域的信道估计方法。本方法联合前导序列和较少的导频数据,分别在时域和频域上完成信道估计,可以获得完整的信道信息,降低了移动环境传输错误概率;通过用PN序列代替数据帧循环前缀进行时域信道均衡,提高了信道估计的精确性,减少了传统伪随机序列OFDM信道估计遇到的符号间干扰。仿真结果表明,在Rayleigh多径信道和城市环境HIPERLAN/2D信道下,相同信噪比下,该信道估计方法接收误码率要明显低于只利用导频的频域信道估计接收误码率。
Aiming at the orthogonal frequency division multiplexing (OFDM) system against multipath fading of wireless channels, this paper presents a joint channel estimation method in time domain and frequency domain. This method combines the pilot sequence and fewer pilot data to complete the channel estimation in the time domain and the frequency domain, respectively, so as to obtain the complete channel information and reduce the probability of transmission error in the mobile environment. By using the PN sequence instead of the data frame cyclic prefix Time-domain channel equalization improves the accuracy of channel estimation and reduces inter-symbol interference encountered in traditional pseudo-random sequence OFDM channel estimation. The simulation results show that under the same signal-to-noise ratio under Rayleigh multipath channel and HIPERLAN / 2D channel in urban environment, the BER of this channel estimation method is obviously lower than that of the channel estimation using only pilot channel.