Little attention has been devoted in the literature to turbo-codes with nonidentical component codes. However, in order to optimize the performance of parallel concatenated schemes with respect to both the so called "error-floor" and the "waterfall" regions, the idea has certain advantages.
['Oscar Y. Takeshita', 'Oliver M. Collins', 'Peter C. Massey', 'J Daniel Costello']
A note on asymmetric turbo-codes