NTT DoCoMo to Conduct Field Trial of 4G Mobile Communications

R&D

TOKYO, JAPAN, May 28, 2003 --- NTT DoCoMo, Inc. announced today plans for a field trial of a fourth-generation (4G) mobile communications system in Yokosuka, Kanagawa Prefecture, where a DoCoMo R&D center is located.

DoCoMo has been conducting research on 4G mobile communications technology since 1998. In indoor experiments announced last October, DoCoMo's 4G system demonstrated maximum information bit rates of 100 Mbps for the downlink and 20 Mbps for the uplink.

The field trial announced today is DoCoMo's next step toward the development of practical 4G technologies, as well as a further contribution by the company toward the establishment of a 4G global standard, which is now being discussed by the International Telecommunication Union's Radiocommunication Sector. (ITU-R).

The field trial will employ Variable Spreading Factor Orthogonal Frequency and Code Division Multiplexing (VSF-OFCDM) and Variable Spreading Factor Code Division Multiple Access (VSF-CDMA) technologies. VSF-OFCDM enables downlink connections of extremely high speeds, both indoors and outdoors, while VSF-CDMA realizes high-speed, high-efficiency packet transmissions for the uplink.

DoCoMo will evaluate the following high-speed transmissions technologies during the field trial:

Effective packet transmission methods
Adaptive modulation and channel coding scheme
Adaptive retransmission control
Adaptive beam forming based on predicted direction of arrival

The Kanto Bureau of Telecommunications granted DoCoMo a preliminary license to conduct the field trial today.

About NTT DoCoMo
NTT DoCoMo is the world's leading mobile communications company with more than 46 million customers. The company provides a wide variety of leading-edge mobile multimedia services. These include , the world's most popular mobile internet service, which provides e-mail and internet access to over 38 million subscribers, and , launched in 2001 as the world's first 3G mobile service based on W-CDMA. In addition to wholly owned subsidiaries in Europe and North and South America, the company is expanding its global reach through strategic alliances with mobile and multimedia service providers in the Asia-Pacific, Europe and North and South America.
NTT DoCoMo is listed on the Tokyo (9437), London (NDCM), and New York (DCM) stock exchanges. For more information, visit www.nttdocomo.co.jp/english

i-mode and FOMA are trademarks or registered trademarks of NTT DoCoMo, Inc. in Japan and other countries.

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