11 September, 2025
In the deployment and optimization of 5G Standalone (SA) networks, ensuring the robustness of the Random Access Channel (RACH) procedure is critical. DIGIS Squared identified and resolved a recurring RACH failure – "FAILURE_MSG4_CT_TIMER_EXPIRED" – during performance testing using our proprietary tools: INOS™ and Katana™. This white paper outlines the nature of the problem, diagnostic process, root cause analysis, and optimization strategies applied to restore optimal network performance.