Dithered Relative Prime Research Articles

On the Equivalence of Interleavers for Turbo Codes

Three of the most common interleavers for turbo codes (TCs) are dithered relative prime (DRP) interleavers, quadratic permutation polynomial (QPP) interleavers, and almost regular permutation (ARP) interleavers. In this paper, it is shown that DRP and QPP interleavers can be expressed in the ARP interleaver function form. Furthermore, QPP interleavers can be seen as a particular case of ARP interleavers, in which the values of the periodic shifts follow the quadratic term of the QPP interleaver function. Some application examples of the equivalent expressions are provided. Particularly, in the QPP interleaver case, the different instances in the Long-Term Evolution standard are considered. Obtained results are useful when investigating a suitable and general permutation model for TCs.

Estimating the minimum distance of large‐block turbo codes using iterative multiple‐impulse methods

AbstractA difficult problem for turbo codes is the efficient and accurate determination of the distance spectrum, or even just the minimum distance, for specific interleavers. This is especially true for large blocks, with many thousands of data bits, if the distance is high. This paper compares a number of recent distance estimation techniques and introduces a new approach, based on using specific event impulse patterns and iterative processing, that is specifically tailored to handle long interleavers with high spread. The new method is as reliable as two previous iterative multiple‐impulse methods, but with much lower complexity. A minimum distance of 60 has been estimated for a rate 1/3, 8‐state, turbo code with a dithered relative prime (DRP) interleaver of length K = 65 536. Copyright © 2007 John Wiley & Sons, Ltd.

Estimating the minimum distance of turbo-codes using double and triple impulse methods

A long-standing problem for turbo-codes has been the efficient and accurate determination of the distance spectrum, or even just the minimum distance, for specific interleavers. This letter compares a number of distance estimation techniques and introduces two new approaches based on iterative processing. The new approaches are more reliable and are particularly useful for long blocks with high minimum distances. Distance measurement results are presented for random, high-spread random (HSR) and dithered relative prime (DRP) interleavers.