为什么说时域卷积为频域乘积，能否通俗的解释？ – 知乎 https://www.zhihu.com/question/29877892
典型序列及信源编码的一种理解 – 找寻最初的美 – CSDN博客 https://blog.csdn.net/mike190267481/article/details/9050369
a. the low-amplitude constellation points are sent with a high probability than the high-amplitude ones. Besides, the constellation points under the same amplitude layer are sent equally likely. Therefore, the average symbol power will be decreased, but at a cost of lower source entropy.
b. The first PS scheme was proposed by Gallager, which is based on many-to-one mapping.
c. There are some methods proposed to further reduce the complexity of CCDM, like multiset-partition distribution matching and sreaming distribution matching.
b. All approaches are variable length, which can lead to varying transmission rate, large buffer sizes, error propagation and synchronization problem.
fixed-to-fixed length codes do not have these issues.