Ensuring Communications Stability

DOCOMO has launched XiTM service, which uses a new mobile communications protocol, Long Term Evolution (LTE) in December 2010.
Compared to W-CDMA, the third-generation communications format used by FOMA, LTE makes data communications even faster and larger capacity. XiTM provides data communications with a maximum download speed of 75Mbps12, which is about 10 times faster than FOMA.
The coverage areas when the service began were Tokyo, Kanagawa Prefecture, Chiba Prefecture, Aichi Prefecture and some part of Osaka Prefecture, but plans call for expansion to cities around the size of prefectural capitals in during fiscal 2011 and to all major cities nationwide during in fiscal 2012. Devices that support XiTM have been steadily put on the market since the service was launched, such as USB data terminals L-02C and F-06C and mobile Wi-Fi routers L-09C and BF-01C. Compatible tablets and smartphones are planned to launch from fall to winter 2011.
Our goal is to raise the current download speed by 2.5 times to 100Mbps by 2014 and achieve a speed equivalent to optical fiber lines. Moreover, in January 2011 we received a preliminary license to test LTE-Advanced, a communications protocol that is even faster than LTE, and have begun testing. In an indoor signal transmission test in a simulated environment, we successfully transmitted a signal at a download speed of approximately 1Gbps and an upload speed of approximately 200Mbps. DOCOMO plans to continue carrying out R&D going forward to further increase the speed and expand the capacity of the XiTM service.

• 1 Maximum communications speed in a partially indoor area. In outdoor and other areas, the maximum download speed is 37.5Mbps.
• 2 Communications speeds are maximum speeds based on technical standards. They are not indicative of actual transmission speeds. The service is provided on a best-effort basis, and actual communications speeds will vary depending on the communications environment and network traffic.

i-mode has grown into one of the world's largest mobile Internet services. DOCOMO is currently implementing a number of measures to ensure operational stability at i-mode Center, the heart of i-mode.
In the area of system operations, we are introducing technologies for self-monitoring communications status, dispersing system processes to multiple devices and switching to backup devices when problems occur.
A manned operations center also monitors i-mode Center 24 hours a day, 365 days a year. Resident maintenance staff are on hand to quickly respond when abnormalities arise. In the area of facilities operations, we are taking steps to improve the seismic performance of i-mode Center facilities and decentralize the device layout.

Major events and exhibitions gather large numbers of customers in a single location. When these customers use their mobile phones at the same time, local base stations have difficulty processing it all, which can cause spotty phone service. We combat this problem by dispersing base station loads and augmenting facility capacity.
Base station loads are dispersed by using multiple base stations to process communications originating at the event venue. This is accomplished by installing temporary base stations at the event and adjusting the coverage area of neighboring base stations. Facility capacity is augmented by setting up base station facilities to cover the venue and modifying the software that controls the facilities to accommodate maximum use.
In fiscal 2010 as well, DOCOMO conducted these special measures to accommodate 39 large events, including fireworks displays in Kanagawa Prefecture, Niigata Prefecture and Fukuoka Prefecture. We will continue working to maintain communications stability by taking appropriate measures like these.