A multilevel approach to constructing trellis-matched codes for binary-input partial-response channels

Filho, Bartolomeu F. Uchôa; Herro, M.A.; Costello, Daniel J.

doi:10.1109/18.796410

Cited by 4 publications

(1 citation statement)

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“…For example, a coding system consisting of a convolutional encoder followed by a precoder with transfer function 1/P n (D) (mod 2) has been considered for the P n (D) channel in [2]- [7]. In these works, a convolutional code with a conventional trellis containing 2 ν states is said to be trellis-matched to the P n (D) channel if the decoder trellis for the composite system has only 2 ν states, as opposed to 2 n+1+ν states [3].…”

Section: Introductionmentioning

confidence: 99%

Graph-Matched LDPC Codes for Partial-Response Channels

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Uchôa-Filho

2008

2008 IEEE International Conference on Communications

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In this paper, we propose an LDPC coding scheme based on repeat-accumulate (RA) codes for partial-response (PR) channels. We modify the original RA encoder in such a way that there exists a one-to-one relationship between a sequence called the D-codeword (which is not the transmitted codeword but contains the information bits) and the noiseless received sequence at the output of the PR channel. A consequence of this is that the graph used for decoding the D-codeword, which is different from the encoder graph, is of low complexity. Moreover, with the appropriate modification of the RA encoder, the graph used for decoding is the same of any PR channel, which makes sense calling these codes graph-matched. The simplicity of the decoder, resulting from the "binary" interference removal (precoding) and the linear, as opposed to quadratic, complexity of the encoder make the proposed scheme attractive. For a code rate R = 3641/4096 = 0.89 and for the PR4 channel, an LDPC code has been designed and a simulated coding gain of about 5 dB for a bit error rate less than 10 −5 was obtained.

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Section: Introductionmentioning

confidence: 99%