Burst error correction capabilities of turbo codes in mobile environments

Interleaving is a standard signal processing technique used in a variety of communication systems. An application of interleaving is in turbo coding schemes where two or more interleaved versions of the same information sequence are encoded. The interleaver allows the component decoders to generate separate estimates of the a posteriori probabilities for a given information symbol based on data sources that are not highly correlated and ensures that the set of code sequences generated has good weight properties. The classical use of an interleaver is to randomise the locations of errors introduced in transmission in order to allow the use of random error correcting codes at the receiver. An interleaver will be used in a system intended to work in mobile environments to counteract the effects of fading causing burst errors. It would be interesting to determine if the turbo interleaver provides the same randomising capacities to the system in order to correct burst errors. For this reason, the turbo interleaver is studied to provide simulation results where its effect is pointed out. Conclusions are provided where the necessity of outer channel interleavers is questioned.