The carrier says it has already been testing LTE in its labs and is aiming to "achieve a downlink transmission rate of 300 Mbit/s."
LTE, which is still in standards development work at 3rd Generation Partnership Project (3GPP) , is the next step on from the HSPA (High-Speed Packet Access) 3G technology currently being deployed by the world's GSM operators. The theoretical downlink capability of HSPA is about 14 Mbit/s. (See chart.)
Table 1: Comparison of 3G and 'Super 3G' Specs
|3G W-CDMA||3.5G HSPA (HSDPA/HSUPA)||3.9G 'Super 3G'|
|Spectrum||3G spectrum*||3G spectrum*||3G spectrum*|
|Spectrum bandwidth||5MHz||5MHz||1.4, 3, 5, 10, 15, 20MHz|
|Radio access scheme||DS-CDMA||DS-CDMA||OFDMA (downlink), SC-FDMA (uplink)|
|Peak data rate (uplink)||384 Kbit/s||5.7 Mbit/s||80 Mbit/s|
|Peak data rate (downlink)||384 Kbit/s||14 Mbit/s||300 Mbit/s|
|Source: NTT DoCoMo|
* 2GHz band and additional spectrum for 3G
DS-CDMA = Direct Sequence Code Division Multiple Access
OFDMA = Orthogonal Frequency Division Multiple Access
SC-FDMA = Single Carrier Frequency Division Multiple Access
DoCoMO says that, in time, its tests will expand from the initial use of just one transmitting and one receiving antenna to using up to four Multiple-Input Multiple-Output (MIMO) antennas on the transmitting and receiving sides, and that it will check out how services such as voice, games, and picture transmission work over the system. (See Multiple Antennas Key to Mobile Broadband.)
The carrier also says it is already "accepting proposals from suppliers seeking to develop Super 3G equipment and expects to complete development of Super 3G technology by 2009," and that the introduction of Super 3G will help its migration to 4G technologies that will use new 4G spectrum. DoCoMo sees 4G being introduced in the 2011-2012 timeframe.
Heavy Reading senior analyst Patrick Donegan believes DoCoMo will be among the first to adopt LTE commercially. "The materials DoCoMo has released with this announcement references HSDPA supporting only 14.4Mbit/s in the downlink whereas 3GPP is evolving Enhanced HSDPA to go to 40 Mbit/s in the downlink and potentially beyond that as well. This suggests that DoCoMo may have a relatively short life cycle in mind for HSDPA, with a view to being among the first to commercialize UTRAN LTE."
As DoCoMo was the global pioneer in terms of 3G rollout, and now has more than 37 million customers for its FOMA 3G, vendors will be keen to prove themselves with the Japanese giant. They'll also want to position themselves as contenders in an LTE equipment market that ABI Research believes will be worth $18 billion between now and 2014.
Among the companies pressing ahead with pre-standards LTE developments are Alcatel-Lucent (NYSE: ALU), Ericsson AB (Nasdaq: ERIC), Nokia Networks , and NEC Corp. (Tokyo: 6701). Having sold its 3G access business to Alcatel-Lucent, Nortel Networks Ltd. is focusing its wireless R&D on what it calls 4G technologies, including LTE. (See Zafirovski: We'll Get 4G Right, Nortel Calls UMB, Alcatel Snags Nortel 3G Unit, and Nortel CEO: 3G Can't Cut It.)
3GPP is expected to release the initial draft of the LTE standards as its Rel-8 in the third quarter of this year.
— Ray Le Maistre, International News Editor, Light Reading