3GPP Minimization of Drive Testing (MDT)
Introduction
3GPP defines the industry standard for combined reporting of UL/DL (Uplink / Downlink) radio quality, call events, user plane QoS and geoposition of UE (User Equipment).
Drive testing is one of the biggest costs of running the network after the energy usage. In a traditional network, drive tests must be done multiple times on different network loads to get an accurate picture of the cell’s coverage and capacity.
To reduce the number of drive tests, the MDT (Minimization of Drive Testing) feature was introduced in release-10.
Two types of MDT have been defined;
MDT measurements can be on Control Plane (C-Plane) or User Plane (U-Plane).
The U-Plane MDT is operator specific with the operator deploying an application on the phone to do these measurements.
The C-Plane MDT is based on signaling and would be standardized across all devices and form factors.
Logged MDT
- Measurements in idle mode
- Logging measurements and reporting later
- Optional for the UE to support.
Immediate MDT
- Measurement in connected mode
- Immediate reporting
- It is Mandatory for UE to support.
It is a feature introduced in 3GPP (3rd Generation Partnership Project) Rel -10 (Release -10). This feature enables operators to utilize users equipment to collect radio measurements and associated location information.
This is to access network performance while reducing the OPEX associated with the traditional drive tests. In 3GPP Rel -11 specifications, MDT (Minimization of Drive Testing) is enhanced to provide a more complete view of network performance.
The operator shall be able to configure UE (User Equipment) measurements independently from the network configuration. The UE (User Equipment) reports measurement logs at a particular event (e.g. radio link failure).
The operator shall have the possibility to configure the logging in geographical areas. All the measurements must be linked with information which makes it possible to drive the location information.
The measurements shall be linked to a time-stamp. The terminal for measurements shall provide device type information, for selecting the right terminals for specific measurements.
Minimization of Drive Testing (MDT) Pillars
It is built on three main pillars:
Reasons for Drive Testing (DT) and Minimization of Drive Testing (MDT)
The operator needs to identify areas where new base stations are needed. The various test can help and provide insight for better capacity planning.
The various test can help to identify weak coverage areas, interference, overshooting, uplink coverage issues, and coverage holes.
The mobile devices try to handover to different cells under certain circumstances. It is critical to minimize any kind of handover failures in the mobile network. The tests provide useful information regarding the source and the target cells and measurement levels under which the failure occurred.
Quality of service (QoS) verification:
QoS is related to delay, service response time, data rate, and packet loss. QoS is usually measured through KPIs and can be identified through the test processes.
