Turbo codes with long frame lengths are usually constructed using a randomly chosen interleaver. Statistically, this guarantees excellent bit-error rate (BER) performance but also generates a certain number of low weight codewords, resulting in the appearance of an error floor in the BER curve. Several methods, including using an outer code, have been proposed to improve the error floor region ...

In digital communication system error correction codes are used when channel is noisy. An error correction code removes errors induced in communication and make possible error free transmission. By use of such error correction code we can send signal at lower transmit power as compared to un-coded system. Convolutional code corrects both type of errors random and burst and used in deep space an...

A link between the theory of error-correcting codes and (t, m, s)nets leads to the efficient construction of two families of very good ternary nets. These have parameters (4r − 4, 4r, (32r + 1)/2 (for all r ≥ 2) and (2r− 4, 2r, (3r − 1)/2) (for all odd r ≥ 3). The underlying codes are cyclic codes.

The paper starts with a short overview of channel coding and the reader is reminded the concept of convolutional encoding. Bottlenecks of the traditional approach are described and the motivation behind turbo codes is explained. After examining the turbo codes design more in detail, reasons behind their efficiency are brought out. Finally, a real-world example of the turbo code used in the thir...

We give efficient constructions for error correcting unordered {ECU) codes, i.e., codes such that any pair of codewords are at a certain minimal distance apart and at the same time they are unordered. These codes are used for detecting a predetermined number of (symmetric) errors and for detecting all unidirectional errors. We also give an application in parallel asynchronous communications.

ETRI Journal, Volume 28, Number 5, October 2006 ABSTRACT⎯The effect of block interleaving in a low density parity check (LDPC)-turbo concatenated code is investigated in this letter. Soft decoding can be used in an LDPC code unlike the conventional Reed-Solomon (RS) code. Thus, an LDPC-turbo concatenated code can show better performance than the conventional RS-turbo concatenated code. Furtherm...

We consider linear error correcting codes associated to higher-dimensional projective varieties defined over a finite field. The problem of determining the basic parameters of such codes often leads to some interesting and difficult questions in combinatorics and algebraic geometry. This is illustrated by codes associated to Schubert varieties in Grassmannians, called Schubert codes, which have...

We present a decoding algorithm for concatenated codes when the outer code is a Reed-Solomon code and the inner code is arbitrary. “Soft” information on the reliability of various symbols is passed by the inner decodings and exploited in the Reed-Solomon decoding. This is the first analysis of such a soft algorithm that works for arbitrary inner codes; prior analyses could only handle some spec...

We propose a new construction and decoding method for concatenated codes. One of the target coding schemes is a serially-concatenated coding scheme with a turbo code as the inner code and a Reed-Solomon (or other block) code as the outer code. The proposed decoding strategies include following two points. (1) New repetitive diagram of whole serial concatenated code is investigated. (2) To reduc...

A double serially concatenated code with two interleaves consists of the cascade of an outer encoder, an interleaver permuting the outer codeword bits, a middle encoder, another interleaver permuting the middle codeword bits and an inner encoder whose input words are the permuted middle codewords. The construction can be generalized to h cascaded encoders separated by h – 1 interleavers, where ...