The recent development of turbo codes has stirred new interest in trying to understand how closely practical codes can approach the theoretical limits on code performance. This article reformulates Shannon’s sphere-packing bound in a normalized form conducive to analyzing the relative performance of families of turbo codes. Even though this bound is achievable only by a (generally mythical) per...

Turbo codes, formed by the parallel concatenation of two recursive systematic convolutional component codes separated by an interleaver, have been proposed for use in a variety of wireless applications, including mobile, satellite and fixed wireless systems. Analysis of their performance requires knowledge of their transfer function, which conveys their distance properties. Using the transfer f...

When using modern Code Division Multiple Access (CDMA) in mobile communications, the user must be able to vary the transmission rate of users to allocate bandwidth efficiently. In this work, Orthogonal Variable Spreading Factor (OVSF) codes are used with the same principles applied in a low-rate superorthogonal turbo code due to their variable-length properties. The introduced system is the Var...

In this letter the impact of the distance spectrum and interleaver structure on the bit error probability of turbo codes is considered. A new turbo code design method for Gaussian channels is presented. The proposed method combines a search for good component codes with interleaver design. The optimal distance spectrum is used as the design criterion to construct good turbo component codes at l...

Compressed images transmitted over noisy channels are extremely sensitive to bit errors. This necessitates the application of error control channel coding to the compressed representation before transmission. This paper presents an image transmission system which takes advantage of the superior performance of Turbo codes, an important new class of parallel concatenated codes. Several aspects of...