NTT DoCoMo boasts of plans for 300Mbps mobile speeds

Stuart Corner
Monday, 16 July 2007 05:03

Opinion and Analysis

Japanese mobile carrier, NTT DoCoMo - one of few carriers left in the world that still retains a large cutting edge in-house R&D facility -  has announced that is working to develop a 'Super 3G' cellular technology capable of delivering 300Mbps downstream. However the announcement raises many questions.

The first one is: why has DoCoMo gone public at such an early stage in the programme, and what does it hope to achieve by doing this? The second is how do DoCoMo's plans mesh with the well developed roadmap raid out by the global 3G standards body 3GPP, the so called Long Term Evolution (LTE)?

All DoCoMo has said is that it will begin with an indoor experiment to test transmission speed using one transmitting and one receiving antenna. The company will then expand the experiment to examine downlink transmission by employing up to four Multiple-Input Multiple-Output (MIMO) antennas for both the base station, on the transmission side and on the mobile station, on the receiving side with the goal is to achieve a downlink transmission speed of 30Mbps.

No real surprises here: MIMO is now well established as an antenna technology for wireless communications in which different data streams are spatially multiplexed using multiple antennas for both transmission and reception on the same frequency, and MIMO with up to four antennas is part of the LTE roadmap.

DoCoMo claims to be '"leading the discussion over LTE" and says it believes Super 3G will allow it to make a smooth transition to 4G in the future. A graph presented with the announement   shows an approximate time for Super 3G to become a commercial reality of 2009 and LTE emerging around 2013, rather later than major vendors are claiming. Also LTE is not expected to achieve a data rate as high as DoCoMo's Super 3G, around 100Mbps only.