What can Immediate MDT do for operators?

As mobile communication networks become increasingly complex, performance optimization and user experience improvement are crucial for operators. Previously, optimization engineers primarily relied on drive tests to perform (physical) measurements of the network to understand and control wireless coverage and performance. However, this testing method is costly, time-consuming, and not always comprehensive.

I. Minimum Drive Testing (MDT) is a wireless network measurement method designed by 3GPP for mobile communication networks. MDT allows the network to collect actual performance data directly from the User Equipment (UE) side, thereby reducing the need for manual drive testing. It is specifically divided into Logged MDT and Immediate MDT (iMDT).

II. Immediate MDT, as defined in 3GPP, refers to the real-time reporting of network performance data by the terminal equipment (UE) during a radio connection session. Unlike logged MDT, which stores data on the device for later upload, immediate MDT sends measurement results to the network, enabling operators to:

• Identify network problems such as radio link failures (RLFs) in real time.
• Collect data at specific locations during the real-time session.
• Improve user performance in real time.

III. Key Points of Immediate MDT The Immediate MDT process during a connection session between the UE and the network mainly includes:

• MDT Configuration: The UE obtains the MDT configuration from the network. This configuration specifies which types of data need to be collected (e.g., RSRP, RSRQ, SINR, or call events).
• Measurement Timing: In a connected state, the UE periodically performs measurements based on specified conditions. Measurement parameters may include signal strength, quality metrics, and location data.
• Coverage Dead Zones and Radio Link Failures (RLF): If the UE finds itself in a coverage dead zone, an RLF may occur, prompting the MDT process to record signal strength and location for further analysis.
• Logger and RLF Indication: During an RLF event, the UE logs key information such as signal strength and location coordinates. After the RRC connection is re-established, an RLF log indication is created and sent.
• Re-establishment and Reporting: The UE needs to re-establish the RRC connection to reconnect. After the RRC reconnection, the UE sends the RLF log indication along with the recorded information. This helps the network identify the location and cause of the RLF, which is very useful for network optimization.