“Good Bye 3G.” KDDI starts VoLTE, focusing solely on 4G.

KDDI, Japan’s second-ranking cellphone carrier, plans to start “au VoLTE”, a voice call service using the LTE network in early December.

KDDI will combine the VoLTE service, featuring a high-definition voice call, with innovative functions that enable a cellphone caller to get his own screen viewed by the other person, and also enable them both to share their positions. Although VoLTE was already employed by NTT docomo in June, KDDI aims to differentiate their VoLTE service with those additional functions.

Currently VoLTE-compatible cellphone models are only two: LG “isai VL” and Kyocera “URBANO”. Sony “Xperia Z3” and Samsung “GALAXY Note Edge”, already on sale, are incompatible.

KDDI and Softbank also start in December to provide the VoLTE service. To the disappointment of consumers, however, NTT docomo, KDDI and Softbank are not connected by VoLTE, unable to deliver high-definition sounds between users of different carriers.

No universal standards for VoLTE connectivity between carriers have yet been established. It is said that any two or more carriers are connected by VoLTE anywhere in the world.

Currently, users of limited models of a specific carrier can benefit from the VoLTE service when they talk with other users of the same model. It is likely to take more time until users can fully enjoy the merits of VoLTE voice calls.

Under such circumstances, no doubt Apple iPhone has the key to the dissemination of VoLTE.

Hardware of iPhone 6 and 6 Plus complies with VoLTE but this compatibility is somehow inhibited in Japan. When asked about the iPhone’s compatibility with VoLTE, KDDI President Takashi Tanaka said, “Apple will choose to comply someday. But I will not comment on specifics at the moment.” He gave no further comment.

Tim cook and  Takashi Tanaka.

Tim cook and Takashi Tanaka.

NTT docomo that has led its competitors in the development of VoLTE is supposed to desire to put an iPhone model on VoLTE but in vain so far.

Should an iPhone become adaptable to VoLTE, the network users would rise explosively in number. They would be able to enjoy the advantage of high-definition voice calls. It would also be good news for all prospective users. It depends on Apple’s intension. The day an iPhone will join VoLTE appears to be undetermined yet.

KDDI will remove the 3G communication function from all new products and restrict their connectivity to 4G.

KDDI has so far used LTE for data communications but based voice communications on the 3G access system, known as CDMA2000.

It says it no longer needs 3G for new models because voice calls will also use LTE, in a show of its audacious attempt to depart from 3G and employ LTE only for data communications as well as voice calls.

If you carry an iPhone 6 of the au version, you will find that not only LTE but also 3G becomes disabled at far corners of an underground shopping arcade, for example.

“If KDDI chooses to solely rely on LTE, the reception range may get smaller and many areas may get out of signal coverage,” says a user, voicing honest concerns of many others.

When asked about this issue, a KDDI person in charge said, “Even 3G-displayed areas are full of LTE signals. Current models are designed to downgrade to 3G before they catch LTE signals. But new models are designed to try to connecti to LTE persistently. So we don’t see any particular problems.”

KDDI President Takashi Tanaka appears confident saying, “Our LTE signal reception ratio reached 99.95 percent as of the end of September.”

The LTE signal reception ratio refers to the probability of a voice call going through completed without a downgrading to 3G. In fact, KDDI has measured the LTE reception ratio on Shinkansen trains. Officials said they were able to continue communicating on LTE at almost all locations on the trains.

The CDMA2000 system has seen a decrease in the number of customer carriers worldwide. Unlike the UMTS system employed on a global scale, CDMA2000 runs on unique specifications. It had its weakness in that a cellphone model with a global downgrade connectivity was difficult to get.

KDDI can hope to make it easier to design such a model by relying solely on LTE and thereby reduce network running costs in the future.

President Tanaka says KDDI will market LTE-compatible models not only of smartphones but also of feature phones sooner or later. “The last conventional models to remain will be module systems for vehicles. Anyway, we will plan to terminate 3G models by 2020.”

KDDI sticks so hard to LTE because of additional costs required to enable a VoLTE model to connect to 3G outside LTE coverage. CDMA2000 specifications are too difficult to conquer.

In addition, there is an issue of emotional feelings of the user who may become frustrated when his cellphone switches over from VoLTE to 3G and the quality of sounds declines as a result.

For these reasons, KDDI says it has attempted to improve LTE signal reception ratios if at all possible with the ultimate goal of enabling all voice calls to be completed on VoLTE.

The risk is quite high for any carrier to focus on 3G-incompatible models. Once the risk is overcome, however, KDDI can get on the easy road to success. This may be the reason why KDDI has made quite a tough decision.

KDDI has been in trouble because of CDMA2000. Compared to Softbank, KDDI was so late in adopting the iPhone. It was despised by competitors because their models were unable to communicate data while their users were speaking. Users in their turn voiced their dissatisfaction, saying the quality of sounds was very bad because sounds were compressed.

CDMA2000 has been the source of bitter hardships for KDDI. Now, however, it is being released from the curse of CDMA2000 and made the first step forward to integration into 4G ahead of the other carriers.

KDDI will have to wait till about 2020 until it becomes completely free of CDMA2000. If all its bandwidth is covered by LTE, however, it can expect an improvement in spectral efficiency. This can work favorably for KDDI, compared to the other carriers. KDDI may even become a textbook example for the world’s carriers running on CDMA2000.