Minimum Energy per Bit of Unsourced Multiple Access with Location-Based Codebook Partitioning

TL;DR

This paper derives bounds on the minimum energy per bit in a Gaussian unsourced multiple access channel with known path-loss, demonstrating performance gains of location-based codebook partitioning over conventional methods.

Contribution

It introduces finite-blocklength bounds and analyzes the benefits of location-based codebook partitioning in heterogeneous path-loss scenarios.

Findings

Location-based codebook partitioning improves energy efficiency.

Numerical simulations show performance gains over conventional UMA.

Large-system analysis quantifies the benefits of the proposed strategy.

Abstract

We derive finite-blocklength bounds on the minimum achievable energy per bit over a Gaussian unsourced multiple access (UMA) channel in the presence of heterogeneous path-loss conditions. We consider a setting in which the path loss is known to the users, which enables the use of location-based codebook partitioning [\c{C}akmak et al., 2025]. Through numerical simulations and a large-system analysis based on the replica method, we quantify the performance gain of this strategy relative to the conventional UMA approach in which all users employ a common codebook.