Talk:Global System for Mobile Communications/Archive 1

Untitled
I think that AMR is only available for UMTS. GSM only provides fixed rate channels right now, and EDGE only transports data normally... Is that not right Mozzerati 06:56, 2004 May 21 (UTC) (no..it's not right it seems.. AMR is available in recent _GSM_ standards.. too much time on packet stuff..)Mozzerati 19:39, 2004 May 27 (UTC)
 * AMR is available on all GSM and only corresponds to only voice, not data. Cacophony 18:53, 4 April 2006 (UTC)


 * I wonder about the disposable cell phone link at the bottom of the page. These have always seemed to be vapourware designed to build hype for an investment con job.  Does anyone have any concrete example of something useful coming out of this or should we just remove the link / move it to a page of fake products?? Mozzerati 05:30, 2004 Jun 9 (UTC)


 * Any idea about health risks?
 * There are many theories, and not a whole lot of data at this point. Cacophony 18:53, 4 April 2006 (UTC)


 * GPRS shares the BSS with GSM, can only be integrated with a GSM network, is a standard retrofit available for almost all GSM networkss, is now almost universally available to GSM customers, is included as standard in almost all GSM mobile phones, isn't used by any other standard and is standardised as an integral part of the GSM standard. I don't think that an argument can be sustained which sees it as in any way a separate network. I plan to delete the disputed tag.  Mozzerati 20:33, 2004 Aug 1 (UTC)

Procedures?
I'd like to do a page on the key GSM system procedures: but I'm not sure what to title it; especially, I think much of the material should be common with WCDMA/3-GSM. Any suggestions? What else should be there? Is this a good split of topics?
 * paging
 * HLR enquiry
 * random access
 * location update
 * Network Switching Subsystem, Base Station Subsystem, Mobility management would be good places to start looking. Cacophony 18:53, 4 April 2006 (UTC)

Thoughts on procedures...
I changed the format of the GSM page to move some of the detailed technical descriptions to a new page called GSM services. I didnt change material, but just stuck it all together, so it probably needs a rewrite anyway which I was planning to do sometime. I think that this page should be a relatively non technical introduction that the casual reader could follow.

But I also had the same kind of idea as you that there should be a procedures page which went into a bit more detail.

Perhaps you could start a page called GSM Protocols and do sub pages for calls, SMS. GPRS and supp services. The main page could explain about MAP, A interface etc etc at the high level, and the sub pages could describe message flows and contents.

I noticed that there is a wiki link created on one of the pages for suupplementary services with no actual content - I had planned to add that in at some stage.

I do think that the main GSM page should be kept as clean as possible - evetually perhaps including an alphabetic index of related categories. ChrisUK

Cleanup for clarity and technicalness
See also Talk:GSM services. -- Beland 12:00, 29 Dec 2004 (UTC)

Visitor Location Register and Home Location Register don't seem to deserve their own articles. The terms are really only meaningful in the context of the GSM system, and they are already or should be fully explained either in this article or in GSM services.

I would recommend moving all the material on SIMs (which is interesting and useful, BTW) to Subscriber Identity Module, and putting a link with a sentence or two of context. Then all the people that get to Subscriber Identity Module from other places will get the benefit of the excellent content currently on this page.

When the term TDMA is used on this page, it's very confusing, because as an American cell phone user, I immediately parse it as "older technology that is not compatible with GSM". It would be good to include a parenthetical clarification or say "the technique of time division multiple access" - not that non-technical users will know what that means unless they click on the link.

mjlodge : Actually, it should be TDM (as in Time Division Multiplexing), not TDMA. This is an accurate statement of what is actually going on (i.e. multiple handset streams are multiplexed into different time slots)

Many of the acronyms used on this page should be written out (for display purposes), otherwise readers not already familiar with the technology will have no idea what article they will get after they click on it (or why they should want to in the first place), or have trouble understanding the meaning of the term in the context of a sentence.

The first paragraph of the "Radio interface" is especially opaque to non-technical readers. I'm sure it could be improved at the price of being slightly longer. Also, when it says, "between stations", does it mean between phones and towers, or between towers, or both? Are all the *DMA techniques used simultaneously, or do they represent mutually incompatible subformats?

For the intro, how many distinct versions of GSM are there? Which one do the "original" phones adhere to? -- Beland 12:00, 29 Dec 2004 (UTC)

History of mobile phones helped a lot to clarify which technologies are 1G, 2G, and 3G. This article doesn't talk much about GSM's relationship with other technologies. It might not be appropriate to do so here, but it would be nice if there were an explanation somewhere about the relative area covered by each technology, where that coverage is, and what its prospects are. This could be done in each technology's home article, but there would need to be tighter links between them, so readers could easily bounce between them. Also, I'm curious whether there are any phones that not only do multiple GSM bands, but also do multiple 2G technologies or 2+3 or 2+2.5 or whatever. Oh, I guess that's answered on Mobile_phone. Hmm. -- Beland 12:14, 29 Dec 2004 (UTC)

The sections on Radio interface, and GSM security should be integrated into GSM protocols (yet to be written), and the sections on SIMs, and Network structure should be integrated into GSM services, the "How GSM works" page. -- Beland 16:29, 9 Jan 2005 (UTC)

erm, one of these 2 articles gives wrong information about data-transfer in gsm:

says: "This fact has also meant that data communication was built into the system from very early on."

says: "It cannot normally transfer data, such as email or software, other than the digital voice call itself, and other basic ancillary data such as time and date."

these two statements are totally opposing.. so, which one is right?!?

greetz  Those conflicting statements resolved. JohnTechnologist 08:32, 24 March 2006 (UTC)

Copyright problem removed
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GMSK vs QPSK
I thought that GSM used GMSK instead of QPSK which is currently indicated in the article. Does anyone know for sure? -- Jeff3000 17:01, July 17, 2005 (UTC)


 * Fixed. R6144 16:59, 21 August 2005 (UTC)

Not in Japan?


I cite: "They were quick to point out that since the phone is GSM, you can’t actually use it in Japan."

So what do they use in Japan? Shinobu 12:19, 3 October 2005 (UTC)


 * NTT DoCoMo uses MOVA (old/proprietary) and FOMA (WCDMA with proprietary core network). Their competitor JPhone (no article it seems..) uses UMTS if I remember correctly.  No idea about others.  Mozzerati 22:18, 3 October 2005 (UTC)

Interesting... thanks! On http://www.japan-zone.com/new/mobile_sim1.shtml they say something similar, although on GSM coverage maps some green blotches are shown around densely populated areas. Yet, if actual GSM is meant... Shinobu 23:01, 3 October 2005 (UTC)


 * That being said, an international WCDMA (UMTS 2100) phone should work in Japan. Or, at least that is what the cingular web site says. nipponese 16:22, 18 October 2006

Roaming
Couldn't you also use roaming in NMT?

GSM
This article is about GSM. Not 3G. So I've removed comparisons between GSM and CDMA2000 since they're pointless. GSM should be compared to cdmaOne not CDMA2000. There might be some room for some comparisons, for example you could mention that CDMA2000 is a more direct upgrade route from cdmaOne then GSM to UMTS/w-CDMA. But talking about w-CDMA coverage or failings in itself is largely irrelevant. [CDMA2000 could be more correctly rendered as cdma2000. JohnT.]

Active editors: Have you thought of writing...
...an article about GPS/SMS bugs? These tiny devices, hidden somewhere at your car, determine its position via GPS and transmit the coordinates via GSM's (or other standards') SMS service to your surveillant(s). They are apparently widely abused by the LEC, secret services or private snoops, thereby infringing on basic civil liberties. Also the aspect of possible counter-weapons could be discussed.

Go to http://en.wikipedia.org/wiki/Talk:Global_Positioning_System and check out '14: GPS tracking'. Feel free to contact me directly, if you prefer.

Michael



A5/1 and A5/2
I removed the part in the article about why soem countries have A5/2 instead of the stronger A5/1 because that reason didn't make sense. A5/1 and A5/2 seems both equally simple to implement in hardware. They constis of three or four shift registres which are irregulary clocked and some XOR-gates. Very similar implementations and both cheap. My personal guess is that the true reason was politics but that is just my guess. Feel free to correct me if I'm wrong.

"A5/1 was developed first and is a stronger algorithm used within Europe and the United States; A5/2 is weaker and used in countries that may not be able to support the infrastructure necessary for A5/1."

Jeltz talk  19:09, 7 April 2006 (UTC)

Addendum to item 8
Calling all GSM experts:

There is now ample evidence that the newer GSM cellphones can be switched on remotely by 'the powers-that-be', and without you noticing it. From that moment on, they can not only be abused as a triangulation bug independent of GPS - cf

http://en.wikipedia.org/wiki/Gps_tracking -,

but also as an eaves-dropping device - their microphone remains 'always on', thus independent of phone calls.

They may be practical for you on the one side, but they can apparently also be a tool from hell.

Michael Laudahn



The state of GSM 850/900 in the US
I noticed a lot of newer 3G world phones are dropping GSM 850. Does this mean anything to us US Cingular customers? I called Cingular sales yesterday and they said using a tri-band phone without 850 in my area (SF bay area) should be no problem what-so-ever, but I think that probably remains to be seen. Can anyone comment on this topic?

Typo?
"Picocells are small cells whose diameter is a few dozen meters" - meaning coverage not size?

Free unlocking from Cingular?
"Cingular and T-Mobile provide free unlock services to their customers after 3 months of subscription." -- As near as I can tell, this is not the case. When I switched from AT&T to Cingular in Spring 2006 (same company, but I was offered a better plan), I wanted to get one of the old phones unlocked instead of buying a new one; the people at the Cingular store (Cingular-owned, not just a franchisee) told me they couldn't do that. I'd had the phone about 18 months. Metageek 14:34, 20 February 2007 (UTC)


 * From memory, AT&TWS never offered unlocking services and didn't set themselves up to be able to unlock their GSM phones. This, of course, arguably bit them in the rear when they were gobbled up by Cingular as it meant Cingular couldn't just send SIMs to people who wanted to switch network but were happy with their existing phones. Cingular themselves do, apparently, on occasion unlock their (Cingular branded) phones. I'm not sure where the "three month" thing comes from, as I don't believe either Cingular or T-Mobile USA have an official, publicly stated, unlocking policy. I'd love to see a cite that proves me wrong however. --Squiggleslash 14:46, 20 February 2007 (UTC)


 * I just moved from Verizon to Cingular/ATT. I bought a KRZR subsidized with a one year service contract on 14 January 2007. I was told at the store that I could call 611 and get the phone unlocked. I did this twelve days after buying the phone. One key seems to be that I said I wanted to unlock the phone for "international travel." The words of the CSR were that this was an "allowed reason." So, no three-month wait, but you've got to say it is for international travel. This seems to be well known within the company and retail stores, but I have no printed source for a cite. RWM 11:25, 27 June 2007 (UTC)


 * Unlock codes are readily available on several websites and you can unlock a phone at any time. This is because in order to get a subsidized phone, you must sign a contract.  If you decide to leave your contract early, they will recoup the cost of the subsidy through the early termination fee.  If you keep paying their monthly fees for the duration of the contract the carrier will recoup the cost of the subsidy through their monthly rates.  The carriers are in a no lose situation once you sign on the dotted line.   Cacophony 02:09, 28 June 2007 (UTC)

Free unlocking from T-Mobile?
"Cingular and T-Mobile provide free unlock services to their customers after 3 months of subscription." has the notation "citation needed".

With respect to T-Mobile, a Google search for "tmobile sim unlock requests" will lead you to http://search.t-mobile.com/inquiraapp/ui.jsp?ui_mode=question&question_box=sim+unlock. Internal my.t-mobile.com search return similar information. I would have added the citation except I could not discern how this should be done for this article since there are no similar examples.

SIM Card Image
It is ironic that the SIM card photo is that of one available from Bell Mobility. Bell Mobility is a CDMA carrier in Canada and from what I can tell this SIM card can only be used in the Motorola A840, which is a CDMA/GSM phone. The purpose is to allow Bell customers to use GSM networks abroad. I mention this since it may cause some confusion for people in Canada - my first reaction before researching this was "Bell is going GSM!?".


 * Is it possible it's not a SIM card at all, but a RUIM? The latter are compatible with SIM readers, so can be used in GSM phones, but provide additional information needed for GSM-style personal mobility to work with IS-95 networks. Wikipedia has no information on the A840 and, in the usual fashion, I can't find any information on the relevent websites to explain how the A840 uses SIMs. --Squiggleslash 16:06, 12 July 2007 (UTC)