WCDMA v. HDSPA v. UMTS

[adam917]

Originally Posted by PhotoJim

My data stick is quad-band GPRS/EDGE (850/900/1800/1900), tri-band UMTS/HSDPA/HSUPA (850/1900/2100). That's close.

We can pick on Europe a bit. If I recall correctly, there is still some Scandinavian coverage with GSM at about 450 MHz. I've never seen any phone that supports these frequencies.

1700 MHz spectrum is just being deployed here in Canada, and 700 MHz spectrum has been auctioned in the US and will be available for cellular deployment as soon as analog TV broadcasting is turned off in the USA. Canada will follow by a couple of years.

The only reason we can get every 2.5G GSM frequency on a device is that the world has stopped adding 2.5G GSM frequencies. There are no GSM radios that do 2.5G at 1700 MHz or 2100 MHz, so there's no need for phones to support those modes.

I thought it was actually CDMA2000 that's deployed on 450 MHz for cheap Internet. It is deployed in about half a dozen countries though. Mostly former NMT countries.

DRNewcomb, ever thought of when 2G/GSM will be expired? We would then certainly need a device that supports all the UMTS bands in use. I see operators that are now deploying 3G on 900 MHz soon starting to cut down on 2G in that band. I guess progress has to happen at some point. We can't keep 2G around forever. Backward compatibility is why devices cost more to make every time a new band is added. I used to be in the camp of keeping the older services running back when it was just one or two bands used for 3G (2100 & 1900) but now it's just getting out of hand. We need to move forward. Sure lots of 2G devices will cease to function once 2G gets turned off but wouldn't they be obsolete anyway? Honestly, how many here regularly use phones over 7 years old, let alone phones that were out since GSM was 1st deployed (10 to 15 years now depending on country)?

Sorry for the rant. I'm going to miss my 2G devices like anyone else but I'm excited for the future of mobile development and keeping backward compatibility is affecting progress.

[DRNewcomb]

Originally Posted by adam917

DRNewcomb, ever thought of when 2G/GSM will be expired? We would then certainly need a device that supports all the UMTS bands in use. I see operators that are now deploying 3G on 900 MHz soon starting to cut down on 2G in that band.

That happens when a carrier has lots of 900 MHz spectrum and not enough 2100. The big problem with UMTS is that it takes 5 MHz per RF channel and a cell needs two channels (10 MHz). While you can build a 2nd rate network with just 10 MHz (one cell "color"), to build a proper system requires 30 MHz (3 "colors"). That's a lot of bandwidth. Many 1900 MHz systems in the US are built on 10 MHz licenses.

I see the replacement for 2G as being something other than UMTS. I understand that the standard actually allows channels less than 5 MHz.

[inquisitor]

Originally Posted by DRNewcomb

That happens when a carrier has lots of 900 MHz spectrum and not enough 2100. The big problem with UMTS is that it takes 5 MHz per RF channel and a cell needs two channels (10 MHz). While you can build a 2nd rate network with just 10 MHz (one cell "color"), to build a proper system requires 30 MHz (3 "colors"). That's a lot of bandwidth. Many 1900 MHz systems in the US are built on 10 MHz licenses.

You seem not to know a basic difference between GSM and UMTS: While in GSM-networks neighbouring cells must use different channels to avoid interferences and so the "Four color theorem" must be observed, in UMTS all cells use the same frequency. So 2 x 5 MHz (5 MHz for the uplink and 5 MHz for the downlink) is enough for a continious network. Of course you can add additional capacity by running a second UMTS-carrier on separate 2 x 5 MHz-channels.
In Germany all the 4 active operators have just 2 x 10 MHz in the 2100 MHz-band.

[DRNewcomb]

Originally Posted by inquisitor

You seem not to know a basic difference between GSM and UMTS: While in GSM-networks neighbouring cells must use different channels to avoid interferences and so the "Four color theorem" must be observed, in UMTS all cells use the same frequency. So 2 x 5 MHz (5 MHz for the uplink and 5 MHz for the downlink) is enough for a continious network. Of course you can add additional capacity by running a second UMTS-carrier on separate 2 x 5 MHz-channels.
In Germany all the 4 active operators have just 2 x 10 MHz in the 2100 MHz-band.

Yes, but the use of a single channel increases the noise floor and reduces the system capacity and data rate. Which is why I said "2nd rate". With GSM systems, cochannel interference will really mess things up. With CDMA it slowly degrades the system. A cumulative effect. UMTS-TDD avoids this problem by time-slicing everything.