The news web sites have it today (here, here and here) that NTT DoCoMo announced today that they plan to switch-off their 2G network in March 2011 and solely rely on their UMTS and LTE networks afterwards. Wow, a great step but they are likely to remain an exception for quite some time to come.
The reason behind that is that DoCoMo uses a 2G wireless technology that's pretty much incompatible with anything else in the rest of the world. In other words, they won't loose a lot of roaming charges with this move.
By switching-off their 2G network they'll significantly save money on two fronts: First, there's one network layer less to to keep running so that certainly saves a great deal of money. Second, they no longer need proprietary dual mode 2G/3G devices and can go forward with dual mode GSM/UMTS mobiles that are sold in the rest of the world (+ an additional frequency band, see below) or triple mode GSM/UMTS/LTE devices. And while we are at it, does anyone know if current devices are still dual mode or has DoCoMo phased this out already and just keeps the 2G network running for legacy devices?
And a final thought on this one for today: Looks like in Japan DoCoMo doesn't only use the 2.1 GHz band for 3G but also a band in the 800 MHz region (FOMA Plus) which is also used by their 2G PDC system. Here's some more details on this from a report on a Blackberry version for Japan. That report also indicates that the band is different from the 850 MHz band used in the Americas. It would be too simple otherwise… So once they switch off their 2G system, they can do further re-farming. Also a nice benefit.
There’s an overview of UMTS bands on Wikipedia: http://en.wikipedia.org/wiki/UMTS_frequency_bands
I wonder when we will finally see chipsets capable of supporting more than three UMTS-frequency bands in one device.
Hello. DOCOMO has kept thier 2G network for legacy devices only. Actually DOCOMO don’t sell dual-mode devices now, and they sold just one dual-mode device N2701 in 2003. The main reason of DOCOMO started 3G network is that their 2G network couldn’t meet the increasend demand for their service due to limited bandwidht, so dual-mode devices interfared with DOCOMO’s aim. Moreover, DOCOMO’s 3G network coverrage has been increasing very fast, and most people are satisified with 3G only devicses. Now, DOCOMO’s 3G netowrk coverage is wider than their 2G network.
You may find some diffculties in reading. Sorry for poor English.
I agree with you. DoCoMo will remain an exception for a long time: I do not see GSM operators switching off their GSM networks in the five next years. Also, these dual mode phones might be more expensive than a pure 3gpp phone due to lack of scale.
Hi Christian,
Yes, 5-band 3G (850, 900, 1900, 2100 and 1700/1900) band support would be even nicer 🙂 This would cover Europe and the US and the main 3G band in Japan (but not their 800 MHz band). O.k. 6-band then 🙂
Cheers,
Martin
Actually, a few years back, Japan restructured its 800 MHz spectrum. Now there is complete overlap between North American “850 MHz” and Japan “800 MHz” allocations. The duplex spacing is 45 MHz in both cases. The main difference is that the allocation in Japan is only 10×10 MHz, whereas it’s 25×25 MHz in North America. It should require no hardware and only a little software to get a North American 850 MHz phone to work in Japan which, I think, was the whole point.
@David
Does an American 3G device actually require modification in order work in Japan? Not only is band VI (Japan) a subset of band V (Americas) in terms of frequencies, but the channel numbers of band VI (UARFCN) are within the range of band V’s channel above).numbers (check the Wikipedia article linked
Band VI seems just to be a cut band V.
@Christian
I suppose I was being conservative. 3GPP went through the trouble to define an 800 MHz band for Japan, as distinct from North American 850 MHz, so I presumed there must be some specific software requirements for a Japan 800 MHz-compatible device.