摘要
为实现FQPSK调制与LDPC码结合的高功率和高效率调制编码系统,需要解码软信息的提取。通过应用卷积码的译码方式,得到了FQPSK的最大后验概率(MAP)软解调新方法,该方法能有效提取译码所需软信息,与LDPC码的SPA译码算法相结合,实现了LDPC码的软判决译码,得到了好的译码性能。FQPSK的新MAP解调比Viterbi解调方式有更好的性能,同时降低了接收机的复杂度。理论分析和仿真结果表明,新方法与多元LDPC码软解码方法联合,提高了功率的利用率和频谱效率,与QPSK调制方法相比,只有很小的性能损失,但系统的整体功率效率得到了提高。
For integrating FQPSK ( Filtered spectrum efficiency system, the decoding QPSK) with LDPC codes together to get high power and soft information is required. By adopting the method of decoding convolutional codes, the soft demodulation MAP algorithm of FQPSK is obtained. The new method can get the channel soft information efficiently. By combining it with the SPA decoding Mgorithm of LDPC codes, the good decoding performance is realized. The new method has good performance while the complexity of the receiver is reduced. The theoretical analysis and simulation results have proved that FQPSK modulation system based on LDPC codes improves the efficiency of system power and spectrum due to the new demodulation, and compared with QPSK, the system has little loss of the performance while the total power efficiency has been improved.
出处
《电讯技术》
北大核心
2009年第11期40-44,共5页
Telecommunication Engineering
基金
国家高技术研究发展计划(863计划)项目(2007AA01Z299
2006AA01Z269)
关键词
深空通信
软解调
最大后验概率
多元LDPC码
FQPSK
deep space communication
soft demodulation
maximum a posteriori probability (MAP)
Q -ary LDPC codes
FQPSK