New criteria for determining improved perforation patterns for variable-rate convolutional codes

This paper presents a new efficient algorithm for determining the perforation patterns yielding variable-rate convolutional coding schemes with improved performance. Given a particular code rate, the new criteria optimize the code for a specific bit error rate, compared to existing techniques searching codes with good asymptotical performance. As an example, the patterns to be used in ultra-wideband systems following the upcoming IEEE standard 802.15.3a were evaluated for different error rates. The new patterns improve the performance of the currently suggested patterns by up to 0.4 dB without changing the structure and complexity of the encoder-decoder.