中文摘要：

首先阐述以可靠度作为度量的低密度奇偶校验码（low-density parity check code,LDPC）译码算法,然后提出低复杂度的连续相位调制（continuous phase modulation,CPM）软解调算法,该软解调算法不依赖于噪声方差,避免了信道噪声方差估计不准确对解调性能带来的影响,最后提出一种低复杂度的联合迭代译码算法,该算法以符号/比特的可靠度作为内外译码器之间的迭代信息,具有简单、易于工程实现等优点。仿真结果表明,新的软解调算法的性能与概率域下的解调算法几乎没有差异;在总迭代次数相同的情况下,采用低复杂度联合迭代的性能相比于未采用联合迭代的性能有约0.75dB的增益。

英文摘要：

A low-density parity check code（LDPC）decoding algorithm which takes the reliability as information metric is firstly described.Secondly,a low complexity soft demodulating algorithm for CPM is proposed.The new demodulating algorithm is independent of variance of noise,which avoids the effect of uncertain estimation of the channel.Finally,a low complexity joint iterative decoding algorithm is proposed,which also takes the symbol/bit reliability as the information metric between inner decoding and outer decoding.The algorithm is simple and easy to apply.Simulation results show that the new demodulating algorithm performs as well as the probabilistic demodulating algorithm;compaing with the decoding algorithm without iterations,the joint iterative decoding algorithm has about 0.75 dB gain,with equal total local iterations.