Multilevel LDPC Lattices with Efficient Encoding and Decoding and a Generalization of Construction D'

TL;DR

This paper introduces efficient encoding and decoding algorithms for multilevel LDPC lattices, along with a generalized Construction D' that simplifies design and maintains high performance close to state-of-the-art lattice codes.

Contribution

It proposes a linear-complexity encoding/decoding method for multilevel LDPC lattices and a generalized Construction D' that relaxes nesting constraints for improved design.

Findings

Performance comparable to polar lattices under multistage decoding

Close to LDLC performance on AWGN channel

Simpler and improved lattice construction

Abstract

Lattice codes are elegant and powerful structures that not only can achieve the capacity of the AWGN channel but are also a key ingredient to many multiterminal schemes that exploit linearity properties. However, constructing lattice codes that can realize these benefits with low complexity is still a challenging problem. In this paper, efficient encoding and decoding algorithms are proposed for multilevel binary LDPC lattices constructed via Construction D' whose complexity is linear in the total number of coded bits. Moreover, a generalization of Construction D' is proposed that relaxes some of the nesting constraints on the parity-check matrices of the component codes, leading to a simpler and improved design. Based on this construction, low-complexity multilevel LDPC lattices are designed whose performance under multistage decoding is comparable to that of polar lattices and close to that of low-density lattice codes (LDLC) on the power-unconstrained AWGN channel.