UE MDT Reporting via RLF Messages and Stored Data
Solution Overview
Problem
In cellular radio access networks, especially in LTE systems, UE-based minimizing drive test (MDT) measurements are not effectively reported when a radio link failure occurs, leading to loss of valuable network management information.
Innovation Solution
User Equipment (UE) stores unreported MDT measurement information during a radio link failure and transmits it upon reestablishment of the link through a Radio Link Failure (RLF) message, enabling network nodes to process and utilize this information for network management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If immediate reporting is used for MDT measurements in RRC-Connected mode, then the network can receive measurement information in real-time, but the measurements are lost when radio link failure occurs
Solution Approach 1:
The UE stores MDT measurement information in advance (in memory or log) before radio link failure occurs, so that the information is preserved and can be reported later through RLF message or logged reporting, preventing information loss due to connection failure
Solution Approach 2:
The patent introduces an intermediary storage mechanism (UE memory/log) that acts as a buffer between the measurement acquisition and the network reporting, allowing measurements to be preserved even when the direct communication path fails
2Loss of information
If the UE stores unreported MDT measurements locally, then measurements can be reported after connection restoration, but additional storage and management complexity is required
Solution Approach 1:
The UE's existing memory and logging mechanisms are utilized for dual purposes: both for general operation and for storing MDT measurements, avoiding the need for separate dedicated storage infrastructure and reducing overall system complexity
Data Source
AI summary
In one embodiment, if a UE is performing minimizing drive test (MDT) measurements and a radio link failure (RLF) occurs, the UE may add MDT measurement information to an RLF message to the network. In effect, the UE “piggy-backs” MDT information in the RLF report, and in so doing, provides greater flexibility to UEs reporting MDT information and more robust reporting. In another embodiment, the UE detects that no allowed reporting channel to report MDT measurement information exists, stores the MDT information, and after detecting that allowed reporting channel exists, initiates establishment of a radio link with the radio communications network during which the UE informs the network using an availability indicator that the UE has stored unreported MDT measurement information to be reported to the radio communications network.