Structured dirty-paper coding using low-density lattices

This paper studies dirty-paper coding in a Gaussian broadcast channel with two receivers. It finds that an approximate version of dirty-paper coding using low-density lattices can be implemented with a complexity that is polynomial-time on average in the block length. The main difference between this paper and prior work is that a non-binary LDPC-based lattice codebook is used for each user, and one codebook is aligned with the other. The low-density nature enables tractable encoding and decoding algorithms, and the alignment gives structure to the overall signal transmitted and it enables us to perform the encoding and decoding efficiently.