TOKYO-NTT DoCoMo Inc. reported success with an experimental fourth-generation mobile transmission that provided data speeds of 100 megabits per second on the downlink and 20 Mbps on the uplink in an indoor lab environment. DoCoMo’s current 3G FOMA network provides maximum data rates of 384 kilobits per second on the downlink and 64 kbps on the uplink.
To deliver such high speeds and wide coverage, DoCoMo said 4G technology requires a bandwidth of approximately 100 megahertz that can lead to a greater number of impairments to transmission quality. To counteract these problems, the carrier’s experimental system employs variable spreading factor and orthogonal frequency code division multiplexing technologies.
The carrier said it has been conducting research on 4G mobile communications since 1998 and has conducted trials on a system that incorporates base station and mobile station equipment to evaluate technologies related to the packet data technology. DoCoMo expects commercial deployment of 4G services by the end of the decade.
