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DoCoMo Produces Mobile Chipset Supporting 100 Mbps Mobile Data Download Speeds

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Japan's DoCoMo says it has successfully developed a trial large scale integration (LSI) chip that consumes less than 0.04 W of power yet supports multiple input multiple output (MIMO) signal detection and decoding for downlink transmissions at 100 Mbps, the speed required for LTE networks.

In September 2007, DoCoMo developed a trial LSI chip that demodulates orthogonal frequency division multiplexing (OFDM) signals and detects MIMO signals transmitted from four antennas at a rate of 200 Mbps, and also consumes no more than 0.1 W of power.

The chip being announced this time demodulates OFDM signals transmitted in the 20MHz bandwidth from two antennas and detects MIMO signals based on Maximum Likelihood Detection (MLD) technology, which ensures relatively high-quality communication even in bad environments for signal reception. The chip also includes error correction decoding, which requires almost the same level of complexity as MIMO signal detection.

In the new chip, which is made with 65-nanometer processing, the circuits have been further optimized, particularly by eliminating redundant circuits for computationally complex processes such as MIMO-signal detection and error-correction decoding.

DoCoMo says that it will incorporate its new LSI chip technology in ongoing research and development of LTE and IMT-Advanced systems, as well as in its active support of the establishment of related international standards.


OFDM - Converts high-speed data signals into multiple low-speed, narrow-band signals that are transmitted in parallel along the frequency axis. Enables greater frequency efficiency and transmissions that are especially robust against multipath interference, such as in urban environments.

MLD - The MLD method detects MIMO-multiplexed signals by comparing the received signals and all possible signals to be transmitted to assess maximum likelihood.

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Tags: lte  docomo  mimo  bandwidth  imt-advanced  Japan