Mobile Calls: 40% Are Churn Inducing

About four out of 10 mobile calls have call quality low enough (Mean Opinion Score score of 2.5) to put the relationship with the customer at risk, a survey of 630 million live mobile calls in 12 countries strongly suggests.

The reason is that subjective call quality below a MOS score of 2.5 is considered "unacceptable" by users and the ITU. When so many mobile calls are right at the threshold, they are, by definition, not "quality" calls.

You might wonder how it is that so many calls, and so many carriers, in so many countries, can have that many calls of questionable quality, when network engineers will tell you the networks are performing quite well.

The problem is that both the survey results and the network engineers are generally right: the "network" is working as it should. The problem is that problems outside the network (ambient environment around the user handset, for example) are disrupting performance. If you test the "network" in the old way, the ambient disruptors cannot be detected.

In mature markets such as the U.S. and Western Europe, 23 percent of all calls fall below the industry minimum. In rapid growth markets, such as the Middle East, India and South America, 59 percent of all calls fall below the industry minimum.

There are three primary issues, says Ken Croley, Ditech Networks director. Ambient noise, or noise that originates in the caller’s environment and enters the device’s microphone, was rated “objectionable” on up to 50 percent of all calls in some regions.

Acoustic echo, which is often caused by mobile handsets and headsets, was rated “objectionable” on up to 11 percent of all calls in some regions. That includes distortion-inducing elements such as Bluetooth ear pieces, for example.

Voice level mismatch, which makes it sound like a caller is speaking either too loudly or too softly, was rated “objectionable” on up to 28 percent of all calls in some regions, and is generally seen as a byproduct of codec mismatches.

The finds came as "a shock to carriers," says Croley. The distortions are "external to the network and missed by the network tests precisely because external to the network." Audio can bounce off a car windshield and back into a microphone, for example.

The corollary is that the problems cannot be fixed by adding more base stations or adding bandwidth. By definition, the issues are caused outside the network, by messiness in the user's aural environment.

Ambient noise levels are an issue as well: think of the trade show floor at CTIA or a crowded bar on Friday night.

The audits were conducted using Experience Intelligence (EXi), a technology developed by Ditech that quantifies the impact of voice quality impairments caused by the places where people make calls, codec impairments, and mobile devices like phones and headsets.

EXi is based on the International Telecommunications Union (ITU) G.107 E-Model, a widely used industry standard, and the technology has been utilized in the communications industry as a complement to existing voice quality test and measurement solutions.

Ditech believes the problems can be fixed by using EXi. Of course, there is the other solution: ban Bluetooth, prohibit talking in noisy places and outlaw talking while driving. Right.