凿孔卷积码距离谱的计算

On the computation of the distance spectrum for punctured convolutional codes

针对基于距离谱的凿孔卷积码优化设计问题,提出了一种高效的凿孔卷积码距离谱计算方法.利用卷积码状态图和凿孔码凿孔图样构造一个长度为凿孔周期的状态转移矩阵序列,并利用状态转移矩阵序列的乘积计算传输函数和距离谱.为了避免符号矩阵的求逆运算,又给出了基于状态逐步消除的传输函数计算方法.分析和仿真结果表明:这种方法既有较高的计算效率,又有很强的实用性,可以用来进行优化设计或者理论分析.

For the optimum design problem of punctured convolutional codes based on the distance spectrum, an efficient computing method of the distance spectrum for punctured convolutional codes is proposed. A state transition matrix sequence is constructed with the state graph and punctured pattern, and the product of the matrix sequence is used to compute the transfer function and distance spectrum; furthermore, a state reduction algorithm for computing the transfer function is proposed to avoid the inverting operation of the symbolic matrix. Analyses and simulation results show that this method for computing the distance spectrum can provide efficiency and practicability, and may be used for optimal design or theoretical analysis.