Bandwidth-Efficient Modulation Codes Based on Nonbinary Irregular Repeat Accumulate Codes

Chiu, Mao-Ching

doi:10.1109/glocom.2008.ecp.224

Cited by 4 publications

(16 citation statements)

References 33 publications

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“…For random-coset GF(q) LDPC and IRA modulation codes, the δ(·) function maps the code alphabet over GF(q) to a q-ary signal constellation A. It has been shown that by using nonuniform PAM signal constellations the constructed codes provide substantial shaping gains [8], [10].…”

Section: Non-binary Random-coset Codesmentioning

confidence: 99%

“…The random-coset GF(q) IRA modulation code was first proposed in [10]. This coding scheme is the binary irregular repeat-accumulate (IRA) code presented in [2] extended to a Galois field GF(q).…”

Section: B Random-coset Gf(q) Ira Modulation Codesmentioning

confidence: 99%

“…One advantage of non-binary codes is that nonuniform pulse amplitude modulation (NUPAM) can be employed. NUPAM provides significant shaping gain [8], [10] as compared to equiprobable uniformly-spaced pulse amplitude modulation (PAM). The results shown in [8], [10] indicate that the non-binary LDPC and IRA modulation codes are better than any codes employing equiprobable uniformly-spaced PAM signal constellations.…”

Section: Introductionmentioning

confidence: 99%

“…EXIT charts are employed in the design of random-coset GF(q) LDPC and IRA modulation codes [8], [10]. However, in the EXIT charts of random-coset GF(q) LDPC and IRA modulation codes, there is no closed-form expression for check node decoder (CND) curves.…”

Section: Introductionmentioning

confidence: 99%

“…In recent works, random-coset GF(q) LDPC codes [8], [9] and IRA codes [10] are applied in bandwidth-efficient modulation schemes which map GF(q) code symbols via random-coset mapping to q-ary channel symbols. One advantage of non-binary codes is that nonuniform pulse amplitude modulation (NUPAM) can be employed.…”

Section: Introductionmentioning

confidence: 99%

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Design and Analysis of Non-Binary LDPC and IRA Modulation Codes

Chiu

2009

GLOBECOM 2009 - 2009 IEEE Global Telecommunications Conference

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It has been shown that, under belief-propagation (BP) decoding, random-coset GF(q) low-density parity-check (LDPC) codes and irregular repeat-accumulate (IRA) codes with q-ary nonuniform signal constellations approach the unrestricted Shannon limit. Extrinsic information transfer (EXIT) charts are employed in the design of random-coset GF(q) LDPC and IRA modulation codes. However, in the EXIT charts of random-cost GF(q) LDPC and IRA modulation codes, there is no closedform expression for check node decoder (CND) curves. The CND curves for random-coset GF(q) LDPC and IRA modulation codes rely on Monte Carlo simulations, resulting in high design complexity. This study presents new design methods for randomcoset GF(q) LDPC and IRA modulation codes based on average zero-word probability. Average zero-word probability serves as a surrogate for LLR messages, just as mutual information acts as a surrogate for LLR messages in EXIT charts. Based on average zero-word probability, closed-form expressions of CND input-output relations are derived for random-coset GF(q) LDPC and IRA modulation codes. Simple convergent criteria for both random-coset LDPC and IRA modulation codes are proposed. Based on the proposed convergent criteria, six codes are designed with nonuniform signal constellations. Simulation results show that the proposed codes have near-capacity performance and are better than any codes employed by equiprobable uniformlyspaced signal constellations.

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Section: Non-binary Random-coset Codesmentioning

confidence: 99%

Section: B Random-coset Gf(q) Ira Modulation Codesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Design and Analysis of Non-Binary LDPC and IRA Modulation Codes

Chiu

2009

GLOBECOM 2009 - 2009 IEEE Global Telecommunications Conference

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On the design of multi-dimensional irregular repeat-accumulate lattice codes

Qiu

Yang

Xie

et al. 2017

2017 IEEE International Symposium on Information Theory (ISIT)

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Most multi-dimensional (more than two dimensions) lattice partitions only form additive quotient groups and lack multiplication operations. This prevents us from constructing lattice codes based on multi-dimensional lattice partitions directly from non-binary linear codes over finite fields. In this paper, we design lattice codes from Construction A lattices where the underlying linear codes are non-binary irregular repeataccumulate (IRA) codes. Most importantly, our codes are based on multi-dimensional lattice partitions with finite constellations. We propose a novel encoding structure that adds randomly generated lattice sequences to the encoder's messages, instead of multiplying lattice sequences to the encoder's messages. We prove that our approach can ensure that the decoder's messages exhibit permutation-invariance and symmetry properties. With these two properties, the densities of the messages in the iterative decoder can be modeled by Gaussian distributions described by a single parameter. With Gaussian approximation, extrinsic information transfer (EXIT) charts for our multi-dimensional IRA lattice codes are developed and used for analyzing the convergence behavior and optimizing the decoding thresholds. Simulation results show that our codes can approach the unrestricted Shannon limit within 0.46 dB and outperform the previously designed lattice codes with two-dimensional lattice partitions and existing lattice coding schemes for large codeword length.

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Achieving the Near-Capacity of Two-Way Relay Channels With Modulation-Coded Physical-Layer Network Coding

Yang

Yuan

et al. 2015

IEEE Trans. Wireless Commun.

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We propose and design a practical modulationcoded (MC) physical-layer network coding (PNC) scheme to approach the capacity limits of Gaussian and fading two-way relay channels (TWRCs). In the proposed scheme, an irregular repeat-accumulate (IRA) modulation-code over GF(q) with the same random-coset is employed at the two users, which directly maps the message sequences into coded PAM or QAM symbol sequences. The relay chooses appropriate network coding coefficients and computes the associated finite-field linear combinations of the two users' message sequences using an iterative belief propagation algorithm. For a symmetric Gaussian TWRC, we show that by introducing the same random-coset vector at the two users, and a time-varying accumulator in the IRA code, the MC-PNC scheme exhibits symmetry and permutation-invariant properties for the soft information distribution of the network coded message sequence (NCMS). We explore these properties in analyzing the convergence behavior of the scheme and optimizing the modulation-code to approach the capacity limit of TWRC. For a block fading TWRC, we present a new MC linear PNC (MC-LPNC) scheme and an algorithm used at the relay for computing the NCMS. We demonstrate that our developed schemes achieve the near-capacity performance in both Gaussian and Rayleigh fading TWRCs. For example, our designed codes over GF(7) and GF(3) with code rate 3 4 are within 1 dB and 1.2 dB of the TWRC capacity, respectively. Our method can be regarded as a practical embodiment of the notion of computeand-forward with good nested lattice code, and can be applied to a wide range of network configurations.Index Terms-two-way relay channel (TWRC), physical-layer network coding (PNC), irregular repeat-accumulate (IRA) code, compute-and-forward (CF).L. Yang is with the School , IEEE Transactions on Wireless Communications 2 of the Gaussian TWRC, the authors of [8], [9] designed binary irregular repeat-accumulate (IRA) coded PNC using an extrinsic information transfer (EXIT) chart curve-fitting technique. Yet, in these works, only BPSK modulation was considered for low or low-to-medium rate regime.It is known that a reliable PNC scheme is of greatest interests in high rate regime. Therefore, the problem of designing practical reliable PNC schemes with high-level modulations and high-rate channel codes is of significant importance. So far, results in this direction are very limited. The main difficulty lies in that the existing multi-level coding (MLC) and bit-interleaved coded-modulation (BICM) schemes [10] based on binary channel codes do not exhibit the ambiguityfree mapping property [13]. This motivates us to design new PNC schemes with high-level modulations to approach the capacity of Gaussian TWRC. In this paper, we aim to design a practical coding scheme whose decoding SNR threshold is close to the capacity limit of the TWRC, e.g. within 1-2 dB for moderately long block length. Such a scheme is said to "achieve the near-capacity performance" of the TWRC.2) Fading TWRC: Although reliable PN...

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Bandwidth-Efficient Modulation Codes Based on Nonbinary Irregular Repeat Accumulate Codes

Cited by 4 publications

References 33 publications

Design and Analysis of Non-Binary LDPC and IRA Modulation Codes

Design and Analysis of Non-Binary LDPC and IRA Modulation Codes

On the design of multi-dimensional irregular repeat-accumulate lattice codes

Achieving the Near-Capacity of Two-Way Relay Channels With Modulation-Coded Physical-Layer Network Coding

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