U.S. operator AT&T and Japanese operator NTT Docomo have begun offering VoLTE roaming services in Japan. AT&T customers traveling in Japan are now able to roam on Docomo’s LTE network and enjoy high-definition voice-calling services in VoLTE coverage areas when calling other AT&T customers who have compatible devices. Docomo serves over 73 million customers throughout Japan, and AT&T’s VoLTE network covers more than 300 million Americans.
Voice-over-LTE, though it debuted in 2014, has been slow to gel. While it is viable within operators’ networks, interoperability is a work in progress. AT&T and Verizon have announced that their users would be able to make VoLTE calls to each other, but the service is still not fully rolled out, and access to VoLTE outside one’s own network is still quite spotty in the U.S.
Furthermore, there are yet other hiccups with VoLTE: The service is reported to suffer from three to four times as many dropped calls as traditional cellular voice systems. On the other hand, service outages are far less common with VoLTE than with traditional cellular calling, giving the service an extra advantage beyond the primary benefit of higher voice quality. In short, VoLTE is a promising technology with definite boons to users and thus to operators, but it still needs all the help it can get in order to fully take hold in the marketplace.
With that in mind, we can see that offering international inter-operability—even before domestic interoperability is completed—can help give the service a boost in the estimation of consumers. In making this arrangement with Docomo, AT&T is playing catch-up; rival Verizon Wireless began operating in Japan over KDDI’s network back in June 2016, at first just for Japanese customers in the U.S., and soon thereafter for U.S. customers in Japan. Depending on the network technology, AT&T and Verizon users’ VoLTE experience in Japan may actually be better than at home.