基于标记位的低密度格码整形方案

摘要

In order to solve the problem that the Low Density Lattice Codes( LDLC) cannot be applied in power limited channels, an LDLC shaping algorithm based on sign bits is proposed. Based on the algorithm of sign bits shaping and combined with the characteristic of low density lattice codes,this algorithm solves the minimizing average power information sequence by the min-sum algorithm. The shaping gain and the information power changes before and after shaping are analized. The simulation result shows that after sha-ping the code power is significantly less than that before shaping. The shaping gain is up to 0. 53 dB. At the same time, it is simple to realize inverse shaping at receiver by using this method.%为解决低密度格码( LDLC)编码后码字不能适用于功率受限信道的问题，提出了一种基于标记位的LDLC码整形算法。该算法结合标记位整形思想，针对LDLC码的特点，通过最小和算法求解出平均功率最小的信息序列。分析并仿真了整形前后信息功率的变化及取得的整形增益。实验结果显示：整形后的码字功率明显小于整形前的功率，可达到0.53 dB的整形增益，同时该整形算法接收端逆整形简单。