Analysis of puncturing pattern for high rate turbo codes

Turbo codes have performance superior than all other coding techniques. The main factors that make turbo codes so efficient include, parallel concatenation structure of the encoding system, recursive convolutional encoder, interleaver, puncturing pattern and iterative decoding. In this research, we have investigated the effect of the puncturing pattern on the performance of high rate turbo codes. Based on simulation results, we claim that for most of the code rates, when a pseudo random interleaver is applied, the selection of puncturing pattern does not have significant effect on the code performance. However, for some rates, a commonly used puncturing patterns does cause much poorer performance. For these rates, a modified puncturing pattern is proposed which restores the performance back to the Shannon limit.