Good k/(k+1) time-varying convolutional encoders from time-invariant convolutional codes

This paper studies the construction of good time-varying convolutional codes from the relation between time-varying and time invariant encoding. In general, an k/n time-varying convolutional code can be described by p n×k generator matrices, where p is the time varying period. Such an k/n time-varying convolutional code may have better error protection capability than the best convolutional codes which has a time-invariant encoder with the same number of states