该文提出了一种基于对称性的双向并行译码方案，用于提高802.16 m标准中双二进制卷积Turbo码(DB CTC)的译码速度。定义了分支度量矩阵以降低译码计算复杂度，定义了前向、后向因子矩阵，推导了前、后向度量递归计算中的对称性，并将其应用于前向、后向度量及后验概率对数似然比的双向并行计算中。构造了采用该方案的DB CTC译码器结构图，详细分析了迭代过程。以计算复杂度，存储空间，译码速度为指标考察了方案的性能，并给出了译码性能仿真曲线。分析表明，该双向并行的译码方法较常规方法提高了一倍的译码速度，而没有增加计算复杂度和存储空间。
This paper presents a bidirectional decoding architecture for double binary convolutional turbo code specified in IEEE 802.16m standard to accelerate its decoding speed. The branch metrics matrix is defined to decrease the decoding computational complexity. Furthermore, the forward factor matrix and backward factor matrix are defined, and then the symmetrical property between them is discussed and applied to the bidirectional calculation of forward metrics, backward metrics and a posteriori log-likelihood ratio. Detailed analyses are presented in terms of computational complexity, memory size, decoding speed and bit error rate, which show that computational complexity and memory size of the proposed architecture are not increased, while the decoding speed is one time accelerated as compared with the conventional scheme.