高阶数据调制比特软输出的递归计算方法

The Recursive Calculation Method of Bit Soft Output

该文设计了一种通过把低阶PAM(QAM)星座图递归排列形成高阶调制的星座图,这种星座图与原信号的关系仍为Gray映射,即相邻两星座点的映射比特序列仅相差lbit。另外高阶调制的比特软输出计算比较复杂,对每一种阶数的调制需要各自的公式计算。研究结果表明高阶调制的比特软输出可以通过低阶调制递归计算得出。只需计算二进制调制方式,就可计算出任意的高阶调制的比特软输出。从而可降低复杂度。仿真表明上述方法简化了高阶调制软信息的计算。

In this paper, a new PAM （QAM） constellation is recursively designed by lower order modulation constellation arrangement, and the constellation is still Gray map. The every higher order modulation bit soft output can be calculated by bit soft output of lower order modulation. The soft output of any higher order modulation can be calculated by calculating the soft output of binary modulation. It can decrease complexity. The simulation shows its correctness.