Novel Power-Imbalanced Dense Codebooks for Reliable Multiplexing in Nakagami Channels

TL;DR

This paper introduces a new family of power-imbalanced dense codebooks designed for reliable multiplexing in Nakagami channels, improving error performance over existing schemes by maximizing minimum distances.

Contribution

It proposes a novel design metric called MLSD and develops power-imbalanced dense codebooks by modifying circulant matrices, enhancing error performance in Nakagami fading channels.

Findings

Proposed codebooks increase minimum Euclidean distance and MLSD.

Significant error performance improvements over existing schemes.

Effective under various overloading factors.

Abstract

This paper studies enhanced dense code multiple access (DCMA) system design for downlink transmission over the Nakagami-$m$ fading channels. By studying the DCMA pairwise error probability (PEP) in a Nakagami-$m$ channel, a novel design metric called minimum logarithmic sum distance (MLSD) is first derived. With respect to the proposed MLSD, we introduce a new family of power-imbalanced dense codebooks by deleting certain rows of a special non-unimodular circulant matrix. Simulation results demonstrate that our proposed dense codebooks lead to both larger minimum Euclidean distance and MLSD, thus yielding significant improvements of error performance over the existing sparse code multiple access and conventional unimodular DCMA schemes in Nakagami-$m$ fading channels under different overloading factors.