Distance measurement method for double binary turbo codes and a new interleaver design for DVB-RCS

The paper presents a computationally efficient distance measurement method for double binary turbo codes, such as these used in the digital video broadcast with return channel via satellite (DVB-RCS) standard, based on Garello´s method. Distance spectra for all standardized DVB-RCS packet sizes and all standardized code rates are presented. A new interleaver design for DVB-RCS based on the dithered relative prime (DRP) interleaving approach is also presented. A minimum distance (d_min) of 36 has been achieved for an unpunctured ATM packet of 424 information bits with a DRP interleaver, whereas the d_min of the standardized DVB-RCS interleaver is 31. A d_min of 38 has been achieved for an unpunctured MPEG packet of size 1504 information bits with a DRP interleaver, whereas the d_min of the standardized DVB-RCS interleaver is 33. Simulation results for code rate 1/3 show an improvement at high signal to noise ratios of at least 0.15 dB and 0.25 dB for ATM and MPEG packets, respectively.