Abstract
Key to the efficient operation of turbo codes is the interleaver design. With proper design, the pairing of low-weight sequences to the input of the encoders can be avoided. Circular shift interleavers can be used to ensure that the minimum distance due to weight-2 input sequences grows roughly as \math , where N is the block length. In this paper, we generalized the mapping function of the circular shift interleaver to be suitable for both equal and unequal error protections. In addition, we present the results of a unique examination of the behavior of the general circular shift interleaver for equal and unequal error protections using turbo code with short frames.