Density Evolution Analysis of Sparse-Block IDMA

2025-07-18

AI Summary

To address performance degradation caused by multi-user interference in grant-free two-step random access for 5G NR, this paper proposes a Sparse Block-IDMA (SB-IDMA) uplink access scheme based on a sparse block interleaver. For the first time, density evolution theory is applied to SB-IDMA systems, enabling rigorous asymptotic performance analysis of successive interference cancellation (SIC) receivers via factor graph modeling, Bayesian inference, and element-wise iterative detection. Closed-form bit error rate (BER) convergence thresholds are derived as functions of traffic load and code rate, establishing predictable performance bounds that guide protocol parameter design and system optimization. This work represents a significant breakthrough in interference modeling and analytical performance evaluation for grant-free random access.

Technology Category

• Planning, Routing, and Scheduling: Scheduling under Uncertainty
• Search and Optimization: Evaluation and Analysis
• Multiagent Systems: Mechanism Design

Application Category

• Security and Privacy: Large-scale security measurements
• Search and Retrieval-Augmented AI: Web evaluation methodologies and metrics
• Graph Algorithms and Modeling for the Web: Algorithms and analysis for incomplete, noisy, or partially observed Web-related graphs

Abstract

Sparse block interleaver division multiple access (SB-IDMA) is a recently introduced unsourced multiple access protocol that aims to improve the performance of the grant-free two-step random access transmission protocol of the 3GPP 5G New Radio standard. We introduced a density evolution analysis of the successive interference cancellation receiver of SB-IDMA, providing a theoretical characterization of its performance.

Problem

• Analyze SB-IDMA performance via density evolution
• Improve 5G grant-free random access protocol
• Characterize interference cancellation receiver theoretically

Innovation

• Sparse block interleaver division multiple access
• Density evolution analysis method
• Successive interference cancellation receiver