LTE is technology being standardized in the 3GPP and is based on "Super3G," which was proposed by NTT DoCoMo Inc. With the view to starting its commercial LTE service in or after 2010, the company is planning to complete its technology development by the end of 2009.

How is DoCoMo, which commercialized third-generation 3G W-CDMA technology first in the world, planning to shift to 3.9G? Nikkei Electronics interviewed DoCoMo's Senior Vice President and Managing Director of R&D Strategy Department Seizo Onoe, who leads the LTE development at DoCoMo.

Q: How will you advance the introduction of LTE? What will be different from the time you introduced 3G?

Onoe: We will be one of the companies that lead the introduction of LTE, but we won't be the runaway leader. We have been standardizing the technology in the 3GPP in view of "globalization" this time, and consider we must be able to offer roaming service immediately after our LTE service starts.

As we have consistently said, "We will complete the development by the end of 2009 to make it possible to commercialize LTE in or after 2010," many carriers across the world are looking at similar timing. Verizon Wireless and China Mobile, for example, have expressed their will to start LTE service in 2010.

The NGMN Alliance, an organization that promotes the specification, and the LSTI, which tests mutual connectivity, are also moving forward, assuming the technology's commercialization in 2010. We will determine the timing of actual introduction while repeatedly conducting connectivity tests with other mobile phone carriers, device manufacturers and handset manufacturers.

In any case, the introduction of LTE will begin at the same time all over the world. That's what's different from 3G, which did not draw much interest for about two years since DoCoMo had introduced it.

Q: What is the most significant advantage of starting LTE at the same time across the world?

Onoe: It's the low prices of base station facilities and handsets resulting from the quick maturity of the technology and market. Suppliers can lower the price more easily if a large market can be expected. Also, if the number of suppliers holding high hopes for the market increases, that will also help the prices drop further. As a result, it will definitely allow users to purchase handset and other related products at low prices and to use LTE services for reasonable fees.

Q: What impacts will users receive from the shift to LTE?

Onoe: In terms of data transmission speeds, I do not think they will surprise users immediately after the emergence of LTE. That is because data rates continuously vary toward the eternal challenge for mobile phone carriers, which aim at lowering service fees by cutting the cost per bit required to build and operate a network.

We consider a minimum bandwidth immediately after the LTE service starts is 5MHz. We are planning to draw its potential little by little, gradually expanding the bandwidth and our service area of LTE, which features potential to achieve a transmission speed of more than 100Mbps at maximum.

The reduction in delays will make users clearly recognize the advantage of LTE, I believe. Delay time is an element that we have not paid much attention to in existing technologies.

This time, we carefully approached delay time from the planning phase, in which we formulated requirement specifications. Both connection delay and transmission delay will be shortened more than one order of magnitude.

For users, it will feel as if the phone is connected all the time, I expect. LTE will facilitate the emergence of a thin client type handset as a result.

Q: Some mobile phone carriers are likely to attempt to make W-CDMA survive longer by introducing "HSPA Evolution" instead of LTE.

Onoe: I don't deny the introduction of HSPA Evolution. Considering that carriers all over the world have different backgrounds and timings, I can understand well that technologies like HSPA Evolution are necessary. What I'm concerned about is whether those technologies will require drastic renovation of base station facilities. I don't care if minor revisions of hardware can generate the results expected from the initial concept.

Shifting to 64-QAM is affordable, but the introduction of MIMO technology will require a much higher cost. Compared with such a drastic change, I believe the introduction of LTE, which utilizes 4G technology before anything else, is more likely to generate higher cost benefits.

In fact, DoCoMo has introduced transmitter diversity technology to many of its base stations, and is, therefore, most advantageous among Japanese carriers, when it comes to shifting to MIMO. It's easy to introduce HSPA Evolution, which is based on MIMO, yet we are intending to choose the potential of LTE.