UK mobile call performance strong and improving

As the UK prepares to say goodbye to its old public switched telephone network (PSTN), blocked calls have become unusual events and call setup times are more than twice as fast as they were five years ago, according to the latest UK mobile call performance trends report from RootMetrics.

The company’s UK mobile call performance trends report looks at blocked call and call setup time trends over the past five years, while dropped call and voice over LTE (VoLTE) trends date back four years. Testing is weighted by population – more samples are collected in bigger cities than in smaller towns – but drive testing is conducted in small communities, rural areas, towns and villages of all sizes.

RootMetrics considers blocked and dropped call rates below 2.0% as excellent. For context, a blocked or dropped call rate of 2.0% means users should experience a call failure during only two out of 100 calls.

The analyst noted that the introduction of a fully digital voice over internet protocol (VoIP) network by 2025 in the UK has been a cause for some concern, particularly because people will eventually lose the ability to make phone calls via a traditional, copper-based landline call network.

While upgrading to digital calling has left some people concerned about the ability to call 999, the RootMetrics report assured that emergency service calls in the UK were given the highest priority by all mobile operators, so even users with poor coverage should see their handset automatically roam to the operator offering the best coverage in that area to ensure calls go through.

Yet the overall conclusion of the study was that whether in major cities, rural areas or somewhere in between, users were experiencing what RootMetrics called “outstanding” mobile call performance, which has continued to improve over time. The data showed that users have been seeing fewer dropped and blocked calls in recent years, along with much faster call setup times. Blocked call rates during UK-wide testing were already low in 2018 and have improved since then – falling from over 4% in 2017 to just 1.7% in 2021.

The highest rate of dropped calls RootMetrics recorded during UK-wide testing was 1.4% in the first half of 2018, well within the 2.0% benchmark that it set for excellent call reliability, and that rate declined to just 1.0% in the second half of 2021. Looking at where quality of service was improving, RootMetrics said mobile users in major cities should see even better performance, with testing across 16 of the country’s most populated metropolitan markets showing blocked and dropped call rates of only 0.6%.

The study also found that call setup times – the time it takes to place a call and for that call to reach the recipient – have shown huge improvement since 2017. The average call setup time in UK-wide testing came in at 2.2 seconds in 2021, down from 4.9 seconds five years ago. RootMetrics largely attributed this improvement to VoLTE usage becoming nearly ubiquitous across the UK for all four major operators.

RootMetrics said VoLTE has several benefits, including faster call setup times and better call reliability in general, and these benefits were shown by the company’s testing. In the first half of 2018, with VoLTE usage at 55.7%, average call setup time was 3.9 seconds. But once the operators’ collective VoLTE usage began exceeding 85% starting in 2019, call setup times have remained below 2.8 seconds.