Non-systematic turbo coding with unequal energy allocation for nonuniform memoryless sources

Abstract

Non-systematic channel codes can have a significant advantage over systematic codes when utilizing redundancy left in the data for channel decoding. However, results previously attained show that even with such codes there is a performance gap to the theoretical limits. We propose a method that combines unequal energy allocation with source controlled decoding of non-systematic turbo codes. The method benefits from both (non-systematic codes and unequal energy allocation) to improve channel decoding performance in the presence of redundancy. Simulations demonstrate superior performance to the performances attained by each of the methods separately. A significant advantage is demonstrated over using non-systematic codes with equal energy allocation. At moderate (more practical) non-uniformities, there is also a clear advantage to the new method over unequal energy allocation with systematic turbo codes