In this contribution we derive the super-trellis structure of turbo codes. We show that this structure and its associated decoding complexity depend strongly on the interleaver applied in the turbo encoder. We provide upper bounds for the super-trellis complexity. Turbo codes are usually decoded by an iterative decoding algorithm, which is suboptimum. Applying the super-trellis structure, we ca...

This study looks at the use of Turbo Codes across a space time spreading (STS) channel in the absence of multi-path. For 3 and 5 iterations, turbo codes was shown to improve the BER by up to 3%. Key Words-Turbo Codes, Space Time Spreading, Bit Error Rate, Transmit Diversity

This paper deals with “Turbo codes”. The turbo code encoder is built using a parallel concatenation of two RSC codes and associated decoder is SOVA. Simulation carried out for different BER, iterations, constraint lengths and frame sizes (FS) to show performance properties of turbo codes in AWGN channel and using binary shift keying modulation. .

The convergence rate of LDPC decoding is comparatively slower than turbo code decoding: 25 LDPC iterations versus 8-10 iterations for turbo codes. Recently, Mansour proposed a ‘turbo-schedule’ to improve the convergence rate of LDPC decoders. In this letter, we first extend the turbo-scheduling principle to the check messages. Second, we show analytically that the convergence rate of both turbo...

1 Facultatea de Electronică şi Telecomunicaţii, Departamentul Comunicaţii, Bd. V. Pârvan Nr. 2, 300223 Timişoara, e-mail [email protected], [email protected], [email protected] 2 Department of Electrical and Computer Eingineering, Rice University, MS-366 – 6100 Main Street, Huston, Texas 77005, e-mail [email protected] Universitatea Politehnica din Bucuresti, Facultatea de Elec...

In this paper, we define a stopping set of turbo codes with the iterative decoding in the binary erasure channel. Based on the stopping set analysis, we study the block and bit erasure probabilities of turbo codes and the performance degradation of the iterative decoding against the maximum-likelihood decoding. The error floor performance of turbo codes with the iterative decoding is dominated ...

Recursive systematic convolutional encoders have been shown to play a crucial role in the design of turbo codes. We recall some properties of binary convolutional encoders and apply them to a search for good constituent convolutional codes of turbo codes. Tables of the “best” recursive systematic convolutional encoders found are presented for various rates, together with the average bit-error p...

| A tutorial introduction to the new class of binary parallel concatenated recursive systematic convolutional codes termed turbo codes is presented. It is shown that such codes are in fact linear block codes, and the encoding operation can be viewed as a modulo-2 multiplication of the information sequence with a generator matrix. A framework for analyzing the performance of turbo codes is propo...

| We study the performance of turbo codes for magnetic recording channels using realistic channel models. Our main objective is to provide a benchmark for the future studies on the subject. We examine a variety of schemes including the use of parallel concatenated turbo codes with and without turbo equalization and convolutional codes with an interleaver (can be regarded as a serial concatenati...