NTT DoCoMo just announced it has achieved a maximum packet transmission rate of approximately 5Gbps in the downlink – claiming a World’s First – using 100MHz frequency bandwidth to a mobile station moving at 10kmh. The field experiment 4G radio access took place in Yokosuka, Kanagawa Prefecture on December 25, 2006. After having achieved a maximum speed of 2.5Gbps in December 2005, DoCoMo doubled the speed in the more recent test by increasing the number of MIMO transmitting and receiving antennas from six to 12 each, and by using proprietary received signal processing technology.
As compared with the December 14, 2005 test, the frequency spectrum efficiency, or the ratio of data transmission rate to channel bandwidth, was also doubled from 25bps/Hz to 50bps/Hz (5Gbps/100MHz). Full press release Here.
Achievements in 4G System Development [.PDF]
Main Technologies of 5Gbps Packet Transmission Experiment [.PDF]
Brough Turner from NMSS posted his opinion, except below, on this news Here.
Their title is flashy, but they were using 100MHz of spectrum. To find that much spectrum you have to look to very high frequencies and thus short ranges with poor penetration of buildings (or trees and shrubs). The benchmark to follow is modulation efficiency — how many bps can you cram through a limited amount of spectrum. Today commercially deployed systems tend to achieve less than 10 bps.
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