There has been renewed interest in iterative decoding algorithms for concatenated codes since the introduction of Turbo codes. Such iterative methods are built on top of soft-insoft-out algorithms. Powerful concatenated codes may be constructed with linear block codes codes as constituent codes. Such codes can be better alternatives to Turbo Codes either when high coding rates or when short int...

In this paper, we devise an efficient joint source-channel coding scheme for robust image transmission over noisy channels. We firstly present a novel interleaver, named unequal row column cyclic cross interleaver, which could improve the error correction capability of turbo codes effectively. Secondly, we devise two types of asymmetric turbo codes which consist of the parallel concatenated tur...

Recent studies have shown that Space-Time code is an effective approach to increasing the data rate over wireless channels. Turbo-based Space-Time codes take advantage of both the diversity techniques of Space-Time systems and the randomness of the Turbo codes. In this paper, we compare two Turbo-based Space-Time Codes and their approximate versions with respect to energy consumption and perfor...

AND TURBO CODES Javier Garcia-Frias and John D. Villasenor Electrical Engineering Department University of California, Los Angeles Abstract|Hidden Markov models have been widely used to statistically characterize sources and channels in communication systems. In this paper we will consider their application in the context of turbo codes. We will describe simpli ed techniques for modifying a dec...

The most powerful channel coding schemes, namely those based on turbo codes and low-density parity-check (LDPC) Gallager codes, have in common the principle of iterative decoding. However, the relative coding structures and decoding algorithms are substantially different. This paper presents a 2048-bit, rate-1/2 soft decision decoder for a new class of codes known as Turbo Gallager Codes. These...

Turbo Codes are very flexible codes and it can be considered as one of the great achievements in the field of communication systems. Turbo Codes have been adopted for wireless digital communication system and they remain unaffected even under heavy traffic situation. The MAX-Log MAP Algorithm which performs necessary computation in Log domain has the capacity to reduce hardware complexity. Majo...

In this paper, we derive bit error performance bounds for turbo codes on Nakagami fading channels with diversity combining. We first derive the average pairwise error probability expressions for turbo codes with maximal ratio combining (MRC), equal gain combining (EGC), and selection combining (SC) on Nakagami fading channels. Using the pairwise error probability expressions and the union bound...