摘要
在时间选择性衰落信道环境中,由于信道参数快速变化,基于判决指引信道估计的正交频分复用(OFDM)系统易受差错传播的影响,恶化系统误码率。针对此问题,文中将期望最大(EM)算法与Turbo均衡原理相结合,提出了一种OFDM系统联合信道估计与符号检测算法。该迭代算法在信道估计与信道译码之间传递软信息,提高了信道估计和信号检测的可靠度,为进一步增强系统对信道时变衰落的鲁棒性,基于信道参数的泰勒级数展开,采用自适应滤波算法实现时变信道跟踪,有效减小了差错传播的影响。计算机仿真表明,在快衰落信道环境中,该算法误码率性能明显优于传统的OFDM信号检测算法。
When applied in the time selective fading channels, the performance of OFDM systems with the decision direct channel estimation can be deteriorated due to the time-varying channel parameters. To overcome this problem, a joint channel estimation and signal detection scheme for OFDM systems is proposed based on the EM algorithm and Turbo principle. By exchanging the soft information between the channel estimator and the channel decoder, the robustness of the channel estimation and signal detection can be both improved. To further enhance the robustness to the channel fading, based on the Tayler series expansion and adaptive filtering, the channel tracking has been realized, avoiding the error propagation for channel estimation. The computer simulation shows that in the rapidly fading channel environment, the BER performance of the algorithm is significantly superior to the conventional detection schemes.
出处
《电子设计工程》
2015年第24期1-4,共4页
Electronic Design Engineering
基金
国家自然科学基金(61302074)
