5G gNodeB UE Context Auditing for Stale User Removal
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Solution Overview
Problem
Stale user equipment (UE) contexts in 5G NR base station systems (gNodeB) persist due to desynchronization and incomplete procedures, leading to resource waste, interference, and service impact, which existing 3GPP mechanisms fail to adequately address.
Innovation Solution
Implementing a method for stale UE context detection and removal at the gNB-CU and gNB-DU using configurable timers, periodic Channel State Information (CSI) reports, and a new audit mechanism between gNB-CU and gNB-DU for active user context synchronization and maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If UE contexts are maintained in gNB-CU and gNB-DU for active users, then user service continuity is ensured, but stale UE contexts accumulate causing resource waste and system performance degradation
Solution Approach 1:
The patent implements preliminary actions by configuring timers and monitoring mechanisms in advance to detect stale UE contexts before they cause significant resource waste. The gNB-CU and gNB-DU proactively monitor UE activity and trigger release procedures when inactivity thresholds are met, preventing stale context accumulation while maintaining active user services.
Solution Approach 2:
The patent establishes feedback mechanisms where the gNB-CU and gNB-DU continuously exchange information about UE context status through interface signaling. This feedback loop enables the system to detect desynchronization, identify stale contexts, and coordinate release actions between gNB-CU and gNB-DU, ensuring resource optimization without impacting active users.
2Reliability
If gNB-CU and gNB-DU are restarted to clear stale UEs, then stale user contexts are removed, but active users are abnormally released causing major service impact
Solution Approach 1:
Instead of restarting gNB-CU and gNB-DU, the patent implements preliminary detection and release mechanisms that identify and clear stale UE contexts before they require system restart. Timers and monitoring procedures proactively manage context lifecycle, eliminating the need for disruptive restart operations that would affect active users.
Solution Approach 2:
The patent extracts and removes only the stale UE contexts from the system while leaving active user contexts intact. Through targeted detection mechanisms and selective release procedures, the system separates stale contexts from active contexts, clearing only the problematic elements without impacting ongoing user services.
3Device complexity
If admission control thresholds are configured based on fixed system capacity, then system resource allocation is simplified, but stale users cause capacity thresholds to be reached affecting new user admission
Solution Approach 1:
The patent implements feedback mechanisms that continuously monitor actual active user counts and synchronize gNB-CU and gNB-DU context states. This feedback ensures admission control thresholds reflect the true system capacity available for new users, preventing stale contexts from artificially reducing admission capability while maintaining simple threshold configuration.
Data Source
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AI summary
A method for stale user context detection and removal is implemented at one of Open Radio Access Network (O-RAN) Centralized Unit (gNB-CU) or Distributed Unit (gNB-DU). In a first variant which utilizes the gNB-CU, the gNB runs a configurable periodic timer for initiating the stale UE detection procedure, i.e., the gNB configures, for every UE context stored in its database, a special Event A1 with the low a1-Threshold = -120 dBm, reportlnterval = 512 ms, and reportAmount = 2. In a second variant which utilizes the gNB-CU, stale UE detection mechanism can be based on a periodic Event A1 configured during initial User admission procedure, i.e., the gNB configures a special Event A1 with the low a1-Threshold = -120 dBm, reportInterval = 1 minute, and reportAmount = infinity. In a further variant, stale UE contexts can be identified at the gNB-DU based on periodic Channel State Information (CSI) reports.