Improving the Decoding Threshold of Tailbiting Spatially Coupled LDPC Codes by Energy Shaping
Journal article, 2018

We show how the iterative decoding threshold of tailbiting spatially coupled (SC) low-density parity-check (LDPC) code ensembles can be improved over the binary input additive white Gaussian noise channel by allowing the use of different transmission energies for the codeword bits. We refer to the proposed approach as energy shaping. We focus on the special case where the transmission energy of a bit is selected among two values, and where a contiguous portion of the codeword is transmitted with the largest one. Given these constraints, an optimal energy boosting policy is derived by means of protograph extrinsic information transfer analysis. We show that the threshold of tailbiting SC-LDPC code ensembles can be made close to that of terminated code ensembles while avoiding the rate loss (due to termination). The analysis is complemented by Monte Carlo simulations, which confirm the viability of the approach.

spatial coupling

tailbiting codes.

decoding threshold

Convolutional LDPC codes


Thomas Jerkovits

German Aerospace Center (DLR)

Gianluigi Liva

German Aerospace Center (DLR)

Alexandre Graell i Amat

Chalmers, Electrical Engineering, Communication, Antennas and Optical Networks

IEEE Communications Letters

1089-7798 (ISSN)

Vol. 22 4 660-663

Areas of Advance

Information and Communication Technology

Subject Categories


Communication Systems



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Latest update

5/2/2018 1