Efficient Context-Aware Barring Scheme for Low-Latency 2-Step RACH in 5G Networks

Nie, Dawei and Yu, Wenjuan and Foh, Chuan Heng and Ni, Qiang and Chen, Luan and Berri, Sara and Chorti, Arsenia and Sun, Hongjian (2025) Efficient Context-Aware Barring Scheme for Low-Latency 2-Step RACH in 5G Networks. In: IEEE INFOCOM 2025 - IEEE Conference on Computer Communications Workshops (INFOCOM WKSHPS) :. IEEE. ISBN 9798331543716

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Abstract

The random access channel (RACH) procedure is critical for uplink synchronization and connection establishment in massive machine-type communication (mMTC). While 3GPP Release 16 introduced the 2-step RACH to reduce signaling overhead, latency incurred due to collisions remains a significant challenge in latency-critical mMTC scenarios. This paper proposes an enhanced 2-step RACH framework that integrates access class barring (ACB) with an action space-reduced contextual multiarmed bandit (AR-CMAB) agent to optimize performance. The proposed scheme dynamically adjusts the barring rate based on real-time traffic conditions, significantly reducing collisions, avoiding backoff delays, and minimizing overall access latency. Simulation results demonstrate that the ARCMAB agent converges much faster than the benchmark scheme while achieving near-optimal latency, outperforming existing methods under varying traffic conditions.