TOKYO, JAPAN, September 13, 2007 ---
In the test, DoCoMo's LSI achieved a transmission rate of 200Mbps with high precision over a high-speed wireless network, while power consumption did not exceed 0.1W thanks to DoCoMo's proprietary signal-processing technology**.
The LSI demodulates and separates MIMO*** (multiple-input multiple-output) -multiplexed OFDM**** (orthogonal frequency division multiplexing) signals transmitted in the 20MHz bandwidth from four antennas. Signal processing is based on MLD (maximum likelihood detection) technology that DoCoMo has originally developed for 4G wireless access.
Redundant circuits have been eliminated in the experimental chip, which was made with 65 nanometer processing.
DoCoMo will continue to develop Super 3G and 4G technologies in combination with its LSI technology, as well as cooperate in the establishment of related international standards.
*Super 3G will provide superfast downlinks in excess of 100Mbps. Super 3G is called Long Term Evolution (LTE) in the 3rd Generation Partnership Project (3GPP).
**DoCoMo's proprietary signal-processing technology is based on MLD, the most accurate method available for separating MIMO-multiplexed signals. The MLD method separates MIMO-multiplexed signals by comparing the received signals and all possible signals to be transmitted to assess maximum likelihood. Although this guarantees accuracy it also requires very heavy computation, but DoCoMo's signal-processing technology reduces computation load while maintaining accuracy.
***MIMO uses multiple antennas on the same frequency to create different data streams that are multiplexed spatially.
****OFDM transmits fast data series using multiple sub-carriers in parallel. The method is especially robust in areas with multipath propagation, such as urban environments.
- About NTT DoCoMo
NTT DoCoMois the world's leading mobile communications company. DoCoMo serves more than 52 million customers, including 38 million people subscribing to FOMA™, launched as the world's first 3G mobile service based on W-CDMAin 2001. DoCoMo also offers a wide variety of leading-edge mobile multimedia services, including i-mode™, the world's most popular mobile e-mail/Internet service, used by more than 47 million people. With the addition of credit-card and other e-wallet functions, DoCoMo mobile phones have become highly versatile tools for daily life. NTT DoCoMois listed on the Tokyo (9437), London (NDCM) and New York (DCM) stock exchanges. For more information, visit www.nttdocomo.co.jp/english.