Construction of Time-Varyng Convolutional Codes

随着Turbo码在1993年的发现，自1948年Shannon发表他的里程碑式论文以来，AWGN信道上的近容量性能首次实现。 最近PI和其他人已经表明，Turbo码是时变卷积码的一种特殊实现;这与过去30年的实践有很大不同，其中强调时不变卷积码。 所提出的工作是一个初步的研究方法，构建类的时变卷积编码器和解码器。 特别是，我们的目标是找到或构建具有稀疏距离谱和长块长度的时变码，而不是最大化自由距离的传统目标。

With the discovery of turbo codes in 1993, near-capacity performance on the AWGN channel was realized for the first time since Shannon published his landmark paper in 1948. It has recently been shown by the PI and others that turbo codes are a particular implementation of time-varying convolutional codes; this differs significantly from the practice of the last 30 years, in which time-invariant convolutional codes have been emphasized. The propose work is a preliminary study of methods for constructing classes of time-varying convolutional encoders and decoders. In particular, the goal is to find or construct time-varying codes with a sparse distance spectrum and long block length, as opposed to the traditional goal of maximizing free distance.