短波信道下联合低密度奇偶校验(LDPC)译码的正交频分复用(OFDM)系统迭代信道估计方法

Iterative Channel Estimation Method of OFDM Systems Jointing LDPC Decoding in the HF Channel

克服短波信道的频率选择性衰落的关键是准确的信道估计,本文针对短波信道的慢衰落特性,提出了短波信道下联合低密度奇偶校验(LDPC)译码的正交频分复用(OFDM)系统迭代信道估计方法,该方法根据迭代估计的思想,首先利用插入导频进行信道初始估计,经过LDPC译码产生可靠的判决信息,通过在信道估计和译码之间迭代地交换信息来完成联合信道估计和译码,提高OFDM信道估计的精度和系统的误码率性能。仿真表明,在相同仿真条件下,与几种传统信道估计算法相比,提出的迭代信道估计算法,可以提高3 dB的编码增益。

In order to overcome frequency selective fading of high frequency （HF） channel, accurate channel estimation is a key method. For slow fading characteristics of HF channel, it is proposed that iterative channel estimation method of orthogonal frequency division multiplexing （ OFDM ） systems jointing low-density parity-check （LDPC） decoding in HF channel, Based on the method of iterative estimation, firstly, we make the initial channel estimation by inserting an pilot, then we can get the reliable judgment information through the LDPC decoding; Finally, we can complete the joint channel estimation and decoding by exchanging information iteratively between the channel estimation and decoding, improve the OFDM channel estimation accuracy and system BER performance. Simulation results show that compared to the conventional channel estimation methods, the proposed channel estimation method can get 3dB coding gain in the same simulation condition.