基于Cordic算法的载波同步方法  

Carrier Synchronization Method Based on Cordic Algorithm

作　　者：李小蓓[1] 杨学兵[2] 蒋华[1] 孙璐[1] 蒲浩[1] 黄涛[1] 吕晨[3] 

机构地区：[1]空军工程大学电讯工程学院 [2]94170部队 [3]93897部队

出　　处：《空军工程大学学报（自然科学版）》2011年第5期72-75,共4页Journal of Air Force Engineering University(Natural Science Edition)

基　　金：空军工程大学电讯工程学院博士启动基金资助项目(KDYBSQDJJ1008)

摘　　要：在通信系统中,相干检测或同步解调时,往往会产生频率偏差。由于一帧数据内各个符号的抽样时刻不一致,随着时间推移,解调出的符号的相位误差会越来越大,致使信号失真严重,译码误码率很高。利用Cordic算法,采用LDPC码高性能的译码特性,提出了一种纠正上述频偏的载波同步方法。该方法首先用Cordic算法来求解频偏,然后再用Cordic算法来修正各个接收信号中由频偏带来的相偏,最后,将修正好的码字送入基于LDPC码译码算法的译码器。仿真结果表明:该方法不但变乘法操作为移位操作,便于硬件实现,而且可以保证LDPC编码系统的性能接近于精确同步情况下的性能。In communication system, frequency warp is often caused by the coherent detection or the synchronous demodulation. Because in one frame the sample time of each code is different from that of other codes, the phase error of the demodulated code and the decoding error would become larger and larger as time goes on. A carrier synchronization method, in which the Cordic algorithm and the efficacious LDPC decoding performance are adopted, is presented to solve the frequency warp. According to this algorithm, the frequency warp is figured out by using the Cordic algorithm, and then the phase error caused by the frequency warp in each receiving code is modified by using the Cordie algorithm again. Finally, the modified code is delivered to the decoder based on the LDPC decoding algorithm. Simulation results show that by using this method not only the muhiplicative manipulation is substituted for the shift manipulation, but also the algorithm＇s performance is approaching to the precise synchronous performance.

关 键 词：低密度奇偶校验码 CORDIC算法 置信传播译码算法 载波同步 

分 类 号：TN911.22[电子电信—通信与信息系统]