Softbank Mobile's Matsumoto
Softbank Mobile's Matsumoto
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Softbank Mobile is planning to apply for a license to use the 1.5GHz band with the view to operating base stations supporting "3.9G" next-generation mobile communications system in Japan in the first half of 2010, the company's vice president said.

Tetsuzo Matsumoto, senior vice president of the company, delivered a speech about the company's approach to the mobile phone business July 23, 2008, at "Wireless Japan 2008."

The cost of LTE seen as a problem

Prefacing things by stating, "This is only an internal decision and Softbank Mobile has yet to make a final decision as a company," Matsumoto introduced his personal views about 3.9G transmission technologies.

When it comes to 3.9G technologies, Matsumoto sees advanced HSPA (he referred to it as HSPA+. It is also called HSPA evolution and eHSPA) as his favorite, rather than LTE (long term evolution), he said.

"We consider the general idea of 3.9G includes 3GPP Release 7 (HSPA+)," Matsumoto said. "We won't go directly to LTE due to its cost issue above anything else. LTE chips are still expensive. In addition, LTE must overcome the hurdle of backward compatibility."

Softbank Mobile seems to consider developing HSPA+ base stations across Japan in the first half of 2010.

"It won't be until 2012 or 2013 when users really start appreciating LTE," Matsumoto said. "LTE will be too costly in 2010. I am not saying that this is 100% sure, but we will choose HSPA+. It has a frequency use efficiency equivalent to that achieved by LTE, while ensuring backward compatibility. I think we can place the emphasis on HSPA+ and prepare ourselves so we can upgrade our networks to LTE in the future."

Advanced HSPA (HSPA+, HSPA evolution) was formulated in 3GPP Release 7. Combined with MIMO technology, the specification can realize high-speed data transmissions at 28Mbps, for example. Unlike LTE, which uses OFDMA technology, the advanced HSPA uses CDMA technology, as does the current W-CDMA.