Runlength-limited Error Control Codes Research Articles

Run length limited CCSDS convolutional codes for optical communications

Abstract This paper presents the construction of RLL-ECCs (run length limited error control codes) from three selected ECCs specified by Consultative Committee for Space Data Systems (CCSDS) for optical communications. The RLL-ECCs obtained present a practical alternative to CCSDS codes with pseudo-randomizers. Their advantage is that the maximal run lengths of equal symbols in their codeword sequences are guaranteed, which is not the case if the common approach with pseudo-randomizers is used. The other advantages are that no additional redundancy is introduced into encoded codewords and that the encoding and decoding procedures of the original error control CCSDS codes do not have to be modified in the following cases: Firstly, if hard decoding is used and the transmission channel can be modeled as a BSC (binary symmetric channel) and secondly, if soft decoding and coherent BPSK (binary phase shift keying) modulation is used and the appropriate transmission channel model is an AWGN (additive white Gaussian noise) channel.

On run-length limited error control codes constructed from binary product codes

Abstract In this paper it is presented that run-length limited error control codes could be constructed from any two or more- dimensional binary product codes as long as at least one of the one-dimensional binary component codes is or can be converted to a run-length limited error control code. The advantages of this construction are as follows: It does not require any additional redundancy except that which is already contained in the original error control code and that the encoding and decoding procedure used for the underlying error control code do not to be changed

Algorithms suitable for low complexity implementation of at class of runlength-limited error control codes

Encoding and decoding procedures which exploit the cyclic-like properties of a class of runlength-limited error control-codes are presented. These algorithms enable simple encoding and decoding circuits consisting of only a few basic circuit elements to be designed. A comparison with conventional syndrome decoding shows that they provide comparable error performance although requiring considerably less circuitry.

Soft decision decoding techniques for a class of runlength-limited error control codes

Two soft decision decoding algorithms for a new class of runlength-limited error control codes with maximum runlength constraints 2, 6 and 14 are presented. Software simulation results for illustrative codes of block length 16 and 64 provide a comparison with the general soft decision decoders proposed by Chase (1972).

Trellis decoding technique for block RLL/ECC

A new simple encoding technique that allows the design of almost all known block runlength-limited error control codes is described. Attention is focused on the most widely used codes (Hamming, Reed-Muller, Golay) with RLL properties. The trellis design procedure for the proposed codes is introduced. It is shown that the trellises of the designed codes are similar to the trellises of the coset codes designed by Forney (1988), and provide low-complexity soft maximum-likelihood performance.

Manchester-like coding with single error correction and double error detection

The spectral features of a class of maximum runlength limited error control codes are determined and are shown, apart from in a singular case, to be the same as those of the Manchester code.

Runlength limited binary error control codes

A systematic procedure is presented for modifying standard binary error control codes (ECCs) to form runlength-limited ECCs without reducing rates or affecting minimum distances. This procedure is then optimised to find the tightest runlength bound given an EEC defined by its generator matrix. A simple example based on the BCH (15,5) ECC is presented to illustrate the procedure, which is nonetheless more generally applicable. The effects of the modification on spectral characteristics are also considered.