MDT (Minimization of Drive Test) is a 3GPP feature first released in Release 10, which was frozen in 2011. And yet, it has not yet made a major impact in the marketplace despite it now being 5 years later.
First, what is it? MDT is a way to enable handsets to both send and log essential measurements. The measurements typically describe the quality of the radio environment, the serving cell, and the neighbor cells. Sending measurement reports is nothing new; every technology from GSM to WCDMA to LTE has included this feature. This allows the network to control the allocation and management of radio resources as well as correctly manage handovers, which is an essential component of providing a mobile service to subscribers. The novel part is where the handset will, on command from the network, log the measurement reports, associate them with a timestamp and then send them.
What is the advantage of that? Well, it addresses the perennial problem where the network KPIs (key performance indicators) say that nothing is wrong, yet subscribers complain that they are out of coverage or unable to make calls.
With logged measurement reports, the handset can record where it was when it experienced issues and the strength and quality of the radio environment as well as describe the neighbor cells. Then, once back in an area of appropriate coverage and quality, it can send the measurements back to the network. So, fundamentally, MDT gives operators more detailed visibility into the performance of the network. This will enable operators to better understand the true user experience, which is essential to prevent churn and drive revenue.
Additionally, as the term suggests, MDT will reduce the amount of drive testing that an operator performs. Drive testing is an expensive and time consuming exercise that frequently fails to reproduce the failures that subscribers encounter. A nuanced MDT approach where reports are sent on coverage and call setup issues, combined with real-time RAN analytics (such as those available in the award-winning RAN Vision solution) will provide full visibility of network performance.
So, why has MDT been delayed? For the usual reasons. Handset vendors prefer to prioritize customer-facing features rather than help operators address optimization issues and network vendors are loath to deviate from the absolute minimal set of features required to deliver service.
As we prepare for the annual migration to MWC (and yes, I will be there, feel free to reach out to me for a chat), I am urging the handset suppliers and network vendors to unleash and use the feature in earnest. I’d also like to remind operators that, in these fiscally restrained times, the easiest way to achieve revenue uplift is to maximize the resources that you have already invested in!