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- 1 Comment
- 2 recent changes to the history
- 3 W-CDMA or WCDMA?
- 4 Vs. GS(R)M?
- 5 WHAT IS THE MAIN DIFFERENCE BETWEEN WCDMA AND CDMA??
- 6 Is FOMA compatible with UMTS or not?
- 7 Common marketing terminology
- 8 GPS
- 9 TD-CDMA, TD-SCDMA and W-CDMA
- 10 Interdigital links here?
- 11 comparison
- 12 Title of article
- 13 Merging
- 14 References to 3GPP
- 15 Move back to W-CDMA
- 16 TDD ?
- 17 Below copied from Talk:W-CDMA
- 18 Redirected to W-CDMA (UMTS)
AFAIK "J-Phone" (now known Vodafone Japan) uses a fully standard UMTS network, and only NTT Docomo's FOMA should be listed as an incompatible variant... I'll change this unless somebody has evidence to the contrary. Jpatokal 08:48, 26 May 2004 (UTC)
recent changes to the history
The statement below gives a historically wrong impression of things: "Now - it was Ericsson that drove the W-CDMA, and proposed it to allow the Americans "a piece of the pie". Nokia has long research in W-CDMA. The agreement between GSM and DoCoMo goes back to 1989 - as "merging technologies". When it comes to all technical issues - like spectral efficiency and QoS/SLA - W-CDMA was the looser."
In fact, Qualcomm went to the trouble to actually develop a wideband system called 3x, which combined features of OFDM and CDMA2000 using (3) 1.25 MHz channels, and strongly begged the Europeans to adopt it instead of W-CDMA. 3x would have had the performance advantages of OFDM and roaming compatibility with CDMA2000 in 58 countries, but the Europeans would not accept this "American" proposal for unity and performance. I wouldn't called Ericsson pro-American. They even sued Qualcomm to get the patent rights essentially for free. As for the spectral efficiency of W-CDMA, it will really shine when there are a lot of users on one tower in a dense city. IT is optimised for this. It may never be as efficient as CDMA2000 in rural areas. But the handset sure are simple, having only one transmitter.
- Looks a whole lot better than it did first thing this morning. Thanks for cleaning it up and fixing some of my contributions too. I have some minor issues, but the only one worth mentioning right now is that I think something along the line of the confusion thing should be here. Common misconceptions should be addressed where those misconceptions occur rather than at specific points in a tree. Arguably much of the CDMA2000x3 stuff should actually be in the UMTS article, as this doesn't pertain to W-CDMA's development much more than, say, EDGE does.
- Anyway, good job Squiggleslash 21:14, 1 November 2006 (UTC)
- I've removed most of the "Deployment" section as it is redundant and too low level. The same information is available in the UMTS article, which is probably a better place. I don't quite understand part of the paragraph describing FOMA, it needs to be reworded, and I've commented it out hoping someone will be offended and put it back in, fixing it. I've also made minor changings to the wording of the last part of the paragraph covering CDMA2000x3 vs W-CDMA, as it was a little confusing as worded (the last part didn't really have much to do with the former part. Arguably the long list of "Despites" should be removed anyway.) Squiggleslash 16:19, 3 November 2006 (UTC)
the removal of ETSI from the history is probably symptomatic of a it being very wrong.
My understanding from memory.
- Originally there were many competing systems. W-CDMA was developed by amalgamating European (==ETSI) and Japanese systems (==DoCoMo) and agreeing a joint standard. Initially several pre-standard systems were implemented by various manufacturers of which only FOMA was put into serious commercial use. Approximately in parallel with the launch of the first W-CDMA networks such as three, the FOMA system was converted to full standard W-CDMA.
Could we find some sources to clear this up? ETSI has never geen involved - GSM was made an CCITT standard before renamed ITU. Now - it was Ericsson that drove the W-CDMA, and proposed it to allow the Americans "a piece of the pie". Nokia has long research in W-CDMA. The agreement between GSM and DoCoMo goes back to 1989 - as "merging technologies". When it comes to all technical issues - like spectral efficiency and QoS/SLA - W-CDMA was the looser. Thus we have a situation where some 3G implementation use TD-SCDMA (e.g. Siemens, Alcatel). GSM is based on ISDN and any "terminal" can be a switch. Now the switch will expose all connections, and be told by IN in the BSC which "channel" to use. Thus it is fully possible to direct data part of GSM on WLAN, if you have a "roaming profile". See ETSI standard for roaming to DECT - allowing a mobile to be used as cordless phone at home and mobile at the same time.(DECT is an ETSI standard - where frequencies are allocated by the ITU). It is also fully possible to make handsets with many "roaming profiles - Nokia N-series support WLAN, and an operator that has rolled out WLAN hotspots, may move data to this for those using these handsets. Saying this - you may also find handsets supporting both W-CDMA and TD-SCDMA on the 2.1GHz.. References on the net. Well, we invented Internet in 1986 at CERN while few used it until mid-'90 -- you ask a lot -khf --KH Flottorp 14:12, 9 July 2006 (UTC)
W-CDMA or WCDMA?
I noticed that this article was moved from WCDMA to W-CDMA a few weeks ago - I'm a little confused because all of the external sites the article links to seem to talk about WCDMA without the hyphen. I'm not an expert on the subject, so would it be possible for someone to explain to me why W-CDMA is correct? Or should it be moved back? Ironfrost 11:23, 15 March 2006 (UTC)
- That is exactly what I wonder, too. WCDMA is the correct term used everywhere, including in the 3GPP specifications. --PauliKL (talk) 15:13, 5 January 2010 (UTC)
- I think that both W-CMDA and WCDMA are correct. The move from WCDMA to W-CDMA may just to show that W-CDMA/WCDMA is exactly a kind of CDMA. From the name W-CDMA we can understand it easier. --Was4444 (talk) 04:22, 21 November 2012 (UTC)
Some history would be nice. Ken 04:27, 18 May 2006 (UTC)
I expect your (R) reflects an intended pun with GPRS.
GPRS is the data part (COS 3 and 4) of GSM. It is circuit switched with full quality of service(3). Because of GSM narrow band - designed to facilitate voice traffic, the first improvement was multi-channel GPRS. Then it is possible, since the connection header identifies the "Class of service" to also specify that the a different modulation to be used and a different frequency. This enabled EDGE - that brings GSM base service to about 300Kbps ("Class 12"). UMTS introduced the capability of a data only net on top of GSM, using the new 2,1GHz frequency. Here the voice and fax service is still on the GSM band, while all data is moved to the 2.1GHz WCDMA band. This releases frequencies that data traffic use on the 900/1800 frequencies for even more voice calls. Beware that session setup/teardown and roaming is still GSM/SS7 signals which make these network incompatible with US networks that insist on using national standards (IS865/IS95 etc.)--KH Flottorp 14:46, 9 July 2006 (UTC)
Erm, well, kind-of.
GSM has had data more or less from the beginning. Circuit switched data in GSM is called CSD. It works in an ISDN-like way (which isn't surprising as much of GSM has its origins in ISDN, GSM is kind of to ISDN what the various analog systems and the US IS series systems were to regular POTS), so there's channel bonding (called HSCSD, though again it's part of "regular" GSM), different types of data (including fax), etc, etc. GSM is, essentially, a circuit switched system, based upon a TDMA air interface, so data in "pure" GSM is difficult to provide in anything but a circuit switched fashion.
GPRS was added in the late nineties and is a packet switched system, using otherwise unused TDMA slots. EDGE works, I believe, the way you describe. Both were designed to be used in any type of TDMA network, but the interfaces between GSM and GPRS were quickly standardized and GPRS has effectively become part of the GSM standard. With the old US D-AMPS networks being the other prime candidates for GPRS, and D-AMPS being easily the weakest of the available mobile phone standards, the remaining D-AMPS operators switched to GSM+GPRS rather than D-AMPS+GPRS.
EDGE, as you said, is an improvement upon GPRS involving more efficient modulation to enable greater data throughput.
EDGE is also a direct extension to GSM (minus GPRS), providing an improved circuit switched mode with greater bandwidth. This only appears to be applicable to data circuits (CSD/HSCSD). I'm not familiar with how this works, but I'd guess that EDGE doesn't increase the number of TDMA slots, so it's only useful for data as a result (increasing the amount of data in a voice call wouldn't necessarily mean you can improve voice quality. But that's another discussion.)
UMTS is a complete refactoring of GSM and has little to do with GPRS or EDGE. It's often known as "3GSM" because it's a 3G version of GSM, and because it's kind of "GSM version 3". In particular, a lot of work was done to separate the air-interface of GSM from the higher level constructs. The availability of higher bandwidths means that certain types of calling, such as video calling, are now possible, so many more services are standardized, and unlike "old" GSM, packet switching is built-in, not an add-on. Squiggleslash 12:41, 6 October 2006 (UTC)
WHAT IS THE MAIN DIFFERENCE BETWEEN WCDMA AND CDMA??
1. Short answer: none, one is a form of the other. 2. Long answer: They're completely different. They're two totally different standards that happen to share a modulation mechanism.
CDMA is used to refer to two things: a modulation system, and a mobile phone standard called IS-95 (and IS-2000, apparently. And some other IS number.)
W-CDMA is a CDMA air interface with particular characteristics. One aspect of it, for example, is that the spread of spectrum used is 5MHz in each direction. That's one aspect, for more, you'll need to do a little reading.
IS-95 is a complete mobile phone standard which uses its own CDMA air interface that has its own characteristics which happen to be entirely different from W-CDMA. Whether that's a good or bad thing depends upon who you talk to, what agenda they have, and what your precise needs are. IS-95 is, however, not just an air interface, although one oft-made criticism of it is that it has precious little else, relying instead upon old AMPS-derived standards for the upper levels.
One characteristic of the air interface used by IS-95 is that it requires 1.25MHz in each direction. (That doesn't mean the air interface part of IS-95 is more efficient with spectrum than W-CDMA, it just means if you're expecting less traffic, you can use a smaller slice of spectrum than you would with a W-CDMA based network. Think of it like a cluster of minibuses compared to a full sized bus.)
There's an awful lot of politics involved here, with a particular, nameless, US company being somewhat obnoxious in its marketing, and a lot of other companies in the same industry reacting to this in kind, so the one thing that's hard to find on the Internet is a genuinely unbiased view of the whole thing. It's difficult to add NPOV stuff to Wikipedia in that environment. One of the things that appears to have caused the most confusion is the notion of air interface technologies being "standards" and exaggerations of the impact a choice of air interface technology will have on an overall system.
That confusion is why people ask what the difference is between chalk and cheese. What is CDMA? It's either a full mobile phone standard (IS-95, IS-2000, etc) or an air interface technology. Either way it can't really be compared to W-CDMA, which is neither. But I hope I've answered your question. Squiggleslash 12:57, 6 October 2006 (UTC)
Seems like this article was written by Qualcomm. The European development is independent of the American/Qualcomm and the main thing common is modulation. IMHO most references to Qualcomm could be removed. CDMA was not invented by Qualcomm, but goes a long way back. W-CDMA is where the market is today. —Preceding unsigned comment added by 22.214.171.124 (talk) 08:49, 4 August 2010 (UTC)
Is FOMA compatible with UMTS or not?
I'm a bit confused, because on the main page of WCDMA it says that FOMA is not compatible with UMTS but if you go to FOMA page it says that it is compatible. Does anybody know what is the latest stand??
- It wasn't before, now NTT Docomo says it is, but there are still quirks in practice. Jpatokal 07:18, 6 November 2006 (UTC)
- I've asked a similar question in the Talk:FOMA FOMA talk area. I think we need terms like "compatible" defined because I'm utterly confused here as to how they're compatible. There's compatible like USIM is with SIM (USIM is a superset of SIM and therefore if you can use a SIM card somewhere, you can use a USIM card in its place.) There's compatible like IPX/SPX is with TCP/IP (they can both live together in harmony on the same network.) There's compatible like an RCA cable is with both audio and video signals (you can use it for either, but they're not the same. ie a UMTS phone might be able to support more complex firmware that means it can also support FOMA, because the hardware is the same.) What is meant by "compatible" in this context? Squiggleslash 14:29, 6 November 2006 (UTC)
Yes it was not compatible before because FOMA is ahead of standards. hoever, As far as Iknow FOMA is changed specifications and Node B upgraded etc for compatible from a couple years ago. —Preceding unsigned comment added by 126.96.36.199 (talk) 11:33, 30 November 2007 (UTC)
Common marketing terminology
It should be pointed out somewhere in this entry that the intended meaning of W[-]CDMA depends on what part of the world you are in and who you are talking to. Broadly speaking, people seem to use W[-]CDMA to refer to whatever 3G CDMA system they expect to see rolled out in their part of the world. In most of the world outside of the US, W[-]CDMA is used to refer to UMTS. In the US it is often used to refer to the 3G variants of the CDMA2000 family. I'm not saying that's correct. I'm saying that's the way the term is typically used. Correct or not, this kind of usage is common and there should be some attempt to clarify this for the reader.
In fact, I'd consider moving much of the content of this page to the various pages for UTMS, FOMA, etc. and replacing the W[-]CDMA entry with an explanation that it is just a marketing term that is abused to refer to a variety of specific cellular standards. The term is nearly meaningless.
- I wouldn't. I've never seen W-CDMA used to describe CDMA2000 or any other 3G standard. It is frequently abused to mean UMTS, indeed Qualcomm themselves bolster that misconception on their W-CDMA page linked in the main article.
- Further, just because it's frequently abused doesn't mean it has no meaning and that the correct meaning shouldn't be described in the article. The term "CDMA" is frequently used to mean "IS-95" and the AMPS-derived protocols that run above IS-95 (even in Wikipedia), but that doesn't stop us from defining it correctly. Unless we do, and sure technical terms are correctly described, it's hard to have a coherent discussion.
- W-CDMA is not a marketing term, it has a meaning. In the real world, I'm only ever seeing it abused to mean "UMTS". I think the article treats it correctly. If you're seeing it to describe CDMA2000, I suggest citing them. Squiggleslash 11:53, 5 November 2006 (UTC)
I know IS-95/IS-2000 uses GPS as part of its synchronization scheme. Does W-CDMA use GPS?
No. See http://www.ericsson.com/technology/whitepapers/innovations_in_wcdma.pdf chapter 4.1
TD-CDMA, TD-SCDMA and W-CDMA
- TD-CDMA, T-SCDMA and W-CDMA are different air interfaces for UMTS. — 3247 (talk) 10:11, 2 June 2009 (UTC)
Title of article
The two articles, W-CDMA and W-CDMA (UMTS), should NOT be merged. W-CDMA is a broad "multiple access" concept, specifically the concept of applying wider band channels than necessary when allocating bandwidth. W-CDMA (UMTS) is a 3gpp standardized version of the broad concept utilized specifically in UMTS and FOMA networks. Therefore, the W-CDMA article should be dedicated to talking about the multiple access technique and how it differs from regular CDMA. And the W-CDMA (UMTS), which should be renamed to W-CDMA (3GPP), should discuss how 3GPP has standardized it for their implementation (i.e. what frequencies and coding schemes are required or optional).Mojodaddy (talk) 07:26, 15 February 2009 (UTC)
- I'm not convinced... Can you find a reference which discusses "W-CDMA" that's clearly not in the context of 3G/UMTS? (i.e. does the term really exist in its own right, or was it "invented" to describe the UMTS air interface?) Oli Filth(talk|contribs) 23:04, 15 February 2009 (UTC)
- Yes, FOMA. Before they converted to using the 3GPP standard, they had their own implementation of WCDMA. The term exists in its own right before the UMTS implementation because DoCoMo invented/used it and then subsequently submitted it to ITU for standardization. See also US6333936 (Notice how Ericsson doesn't suggest or limit themselves to UMTS anywhere in the spec), US6353626 (Nokia's implementation of WCDMA in IS-95). I can find more if you want. —Preceding unsigned comment added by Mojodaddy (talk • contribs) 07:31, 16 February 2009 (UTC)
- To be fair, both patents are talking about third-generation technologies (i.e. 3G), but I concede the point that they're not talking about UMTS specifically!
- I guess one concern I have that on its own, does "W-CDMA" really any more than the sum of its parts, i.e. "wideband" (a relative term) and "CDMA"? Oli Filth(talk|contribs) 09:29, 16 February 2009 (UTC)
- FOMA is NTT's trademark for UTRA-FDD (=UMTS-FDD=W-CDMA). The FOMA trademark also encompasses some additional services such as i-mode. However, the W-CDMA part is now mostly identical. A good overview can be found at . strong merge. —3247 (talk) 10:35, 1 June 2009 (UTC)
- Well, here are some references:
- , p. 7, says that UMTS, FOMA and W-CDMA are the same. (This, of course, is only true if you completely ignore UMTS-TDD.)
-  says that the air interface is called W-CDMA, whereas the channel access method is called DS-CDMA. It also puts “W-CDMA” side-by-side with “GSM”, talks about roaming, and FOMA.
-  says that FOMA merely used a pre-release of UMTS.
- I think that's enough. — 3247 (talk) 02:03, 12 June 2009 (UTC)
- Well, here are some references:
References to 3GPP
I would think that http://www.3gpp.org/ has a lot of documents relevant as references for this page, in particular specifications for WCDMA and other standards. It's a bit difficult to find the relevant documents, so external links from here would help. --HelgeStenstrom (talk) 16:01, 18 February 2009 (UTC)
Move back to W-CDMA
W-CDMA (UMTS) → W-CDMA — W-CDMA is not just a channel access method. It's a common name for an air interface that uses CDMA, just as CDMA2000 is a common name for another air interface using CDMA. All usages of W-CDMA relate to the air interface (or its pre-standard version deployed by NTTドコモ). — 3247 (talk) 10:11, 2 June 2009 (UTC)
- Administrator note: Invalid move request. In order to move this, the article at W-CDMA would have to be deleted, which can only be done through WP:AFD, WP:PROD, or WP:CSD, not WP:RM. A retitling in this instance is better accomplished through merging the articles. Cheers, --Aervanath (talk) 17:39, 10 June 2009 (UTC)
- Well, being WP:BOLD, I've done the merge. There's no reason to keep the “ (UMTS)” suffix, so the move request remains. I'll re-list it when the dust has settled and people who disagreed will have had their chance to revert. — 3247 (talk) 02:08, 12 June 2009 (UTC)
- further discussionmoved to → Talk:Universal Mobile Telecommunications System#Confusion surrounding multiple access terminology — 3247 (talk) 19:44, 24 June 2009 (UTC)
Is the reference to TDD in the introduction correct. Depending on the exact interpretation I would have expected TDD and FDD or just FDD but not TDD alone.
Below copied from Talk:W-CDMA
Redirected to W-CDMA (UMTS)
W-CDMA is not a special channel access method as this article claimed, but a radio interface standard. DS-CDMA is the name of the channel access method. So I merged the article with and redirected it to W-CDMA (UMTS). Mange01 (talk) 14:58, 2 January 2010 (UTC)