5G NR Inter-Layer and Cross-Layer Issues: Root Causes and Solutions

The following are common 5G NR test cases for inter-layer and cross-layer issues, including their failures, root causes, and solutions/suggestions.

Failure Case #1: Inter-Layer Timing Mismatch

Root Causes:

• Incorrect timer configurations between PHY, MAC, and RLC layers.
• Asynchronous operation due to clock drift.
• Software bugs in cross-layer communication.

Solutions/Rectifications:

• Ensure tight synchronization between protocol layers using proper timing configurations.
• Regularly test and validate inter-layer procedures under different network conditions.
• Optimize timers to match operational requirements and prevent desynchronization.

Failure Case #2: Inconsistent State Between Layers

Root Causes:

• Misalignment in state management between MAC, RLC, and PDCP layers, causing lost or duplicate PDUs (Protocol Data Units).

Solutions/Rectifications:

• Implement robust state management procedures to maintain consistency across layers.
• Ensure proper inter-layer communication and signaling to prevent state mismatches.
• Use cross-layer optimizations to align protocol behavior based on network conditions.