Thursday, February 23, 2006

NTT DoCoMo Experiment Achieves 2.5 Gbps Wireless Downlink Speed

NTT DoCoMo reported achieving an astonishing 2.5 Gbps wireless packet transmission in the downlink while moving at 20 km/h by using MIMO (multiple-input multiple-output) and quadrature amplitude modulation (QAM) techniques. The fourth-generation (4G) radio access field experiment took place in Yokosuka, Kanagawa Prefecture on December 14, 2005.

DoCoMo achieved a maximum 1 Gbps speed in a similar field experiment on May 9, 2005. This time, by increasing the number of MIMO transmission antennas from four to six and by using 64-QAM, data volume per transmission was increased from four bits to six bits. As a result, DoCoMo achieved a maximum speed of 2.5Gbps, which is faster than the International Telecommunication Union Radiocommunication Sector (ITU-R)'s proposed standard.

Frequency spectrum efficiency, which is expressed as information bits per second per Hertz, was also increased from 10 bits per second per Hertz during the last experiment to 25 bits.

See also