Japanese Mobile System Hits 250M bps

NTT DoCoMo has achieved a download speed of 250M bps (bits per second) in trials of a future 3G cellular technology.

The speed was attained in outdoor tests near the carrier's research and development laboratory in Yokosuka, Japan, in February this year and is the latest step NTT DoCoMo has taken towards a possible commercial launch of the technology early in the next decade.

Dubbed "Super 3G" by NTT DoCoMo, it is one of a number of systems that is included under the "Long Term Evolution" banner of the 3GPP (3rd Generation Partnership Project), the standards setting body for 3G cellular systems, said Shuichiro Ichikoshi, a spokesman for NTT DoCoMo in Tokyo.

DoCoMo stared working on Super 3G in July 2006 as a stepping stone technology to bridge the gap between current HSDPA (high-speed downlink packet access) technology and 4G cellular systems.

The first 3G systems were capable of data transmission at speeds up to 384K bps but can now support downloads in the megabit per second range thanks to HSDPA systems. NTT DoCoMo's network in Japan currently offers download speeds up to 3.6M bps and from April 1 will support up to 7.2M bps. Such technology is expected to scale up to around 100M bps but there's a big gap between that point and 4G speeds of 1G bps.

As carriers want to wring out every bit of life possible from cellular networks the commercial launch of LTE should mean that 3G technology is good for a few more years before customers and applications begin demanding faster transmission.

NTT DoCoMo is also looking at 4G systems and has already managed to transmit data at close to 5G bps to a receiver moving at 10 kilometers per hour using 4G technology.

The carrier hopes Super 3G development work will be completed by the end of 2009, said Ichikoshi. That means commercial services, if launched, would begin in 2010 at the earliest.

More details of NTT DoCoMo's Super 3G tests will be presented at the CTIA Wireless 2008 show that begins in Las Vegas on April 1.