Talk:Comparison of mobile phone standards
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[edit] Vandalism
is this Avneesh Rupal's personal page?--Hattusili 12:21, 20 June 2006 (UTC)
- No, but this seems to be the only page that user has ever edited, and I don't think there's ever been a good edit. I've added a note to the user's talk page. --Mdwyer 18:14, 13 November 2006 (UTC)
- I take that back and apologize. Apparently, Avneesh wrote the initial article. However, editors on Wikipedia generally do not sign or otherwise take ownership of an article. --Mdwyer 06:02, 13 January 2007 (UTC)
[edit] Apples/Pears
Isn't comparing GSM to CDMA like comparing Apples and Pears... Or even Apples and Peanuts.
Compare GSM vs. UMTS, etc. and then Compare CDMA, FDMA, etc. would be more usefull I guess.
- Moreso we're comparing Fruits to Oranges. Technically, we should be comparing TDMA versus CDMA, possibly against FDMA. Especially since the lines are getting rather blury. I understand that the next generation of GSM services is going to use a CDMA air-interface. I think what the article is trying to do, however, is compare the GSM phones used by most of the world with the CDMA phones used by some American carriers and much of the Asian markets. Frankly, the stuff I wrote was comparing my SprintPCS CDMA phone against what I know of a friend's T-Mobile phone.
- This article really doesn't need to be here -- it just invites religious wars. I hoped I could add a little more to it, though. --Mdwyer 05:11, 19 July 2006 (UTC)
- Wow, good analogy with "fruites and oranges", better then mine (Apples/Pears). I see, there have been some changes made towards this. I'll see what I can do to improve it further... Tried a few things here and there, didn't like it in the end, so I didn't submit. I don't think this will go anywhere. IMO the article should be either completely rewritten (which I don't have time/will to do) or deleted since as it is now it doesn't make any sense from either a technical or a scientific point of view. -def
- Gosh, I dunno... I kind of liked this article. I was trying to understand Qualcomm's big to-do in India, and the combination of this article and the individual articles on CDMA and GSM, along with Qualcomm cleared everything up for me. I was considering buying Qualcomm stock, and since their CDMA patents are pretty much their biggest asset, this article helped me understand what is perceived as the major alternative (GSM) and how it compares. Beagley
[edit] Power consumption
It doesn't seem to follow that CDMA uses less power than GSM. GSM phones are almost invariably smaller than equivalent CDMA phones, and have longer talk and standby times. My coworkers with CDMA phones are amazed that I can go a week or more without charging my tiny little phone, and can talk for 4 hours. If the article is saying that CDMA cell 'towers' use less power, then that should be made clear. ~19:41, 7 December 2006 (UTC)
[edit] History and security
My company is trying to outlaw GSM phones based on a claim that they are less secure than CDMA phones. I've found evidence that some of the GSM algorythms have been cracked, but localo cell providers tell me that their implementation doesn't use these algorythms because they're obsolete.
Now my company's security guy is claiming that CDMA is more secure because it was developed by the US military. (They also developed Ada (programming language), but that doesn't make it better than any other computing language) Unless the reference is to the use of CDMA in GPS, I haven't read anywhere that the US military was involved in CDMA.
I would like to see some comparison of security for the two standards from someone with experience in the area. ~19:41, 7 December 2006 (UTC)
- This comment doesn't make any sense for the same reasons as above. There is no GSM vs. CDMA, since 3G GSM does use CDMA. CDMA was not developed by anybody, it is just one of the different possible principles of how to manage concurrent access to one single ether. Anybody could develop his/her own TDMA, FDMA or CDMA protocol as he/her likes. --65.241.15.227 01:20, 10 January 2007 (UTC)
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- CDMA certainly has uses in the military, because it is difficult to jam and very spectrum-efficient. It is also somewhat difficult to detect, since it doesn't show up on a traditional radio scanner. I rather like Steve Denbeste's answer: It is harder than a wired phone, but possible to eavesdrop[1]. If someone wants to monitor your calls, they can do it easier by monitoring the wired portion of your call. Your cell phone isn't totally secure -- nothing is -- but it is usually more than sufficient, and it is MUCH better than the old AMPS phones, which you could listen to with any old scanner.
- For what it is worth, CDMA's 'encryption' hasn't been broken yet, to my knowledge. --Mdwyer 17:14, 10 January 2007 (UTC)
[edit] IS-95 and the iPhone
I have deleted for the second time something about how the iPhone is being released for GSM only so far. I don't think this is the right audience for this kind of sour-grapes stuff, so I have removed the specific mention of the iPhone again. Instead I mentioned that features come later to CDMA phones. I don't even think THAT is true, though -- CDMA has been leading the charge in high-speed data, and I'm pretty sure they were the first to have GPS functionality in their phones.
- As an aside: The fact that the American phone companies can't seem to deliver the PRODUCTS is another issue entirely *grumble*. Here's some sour grapes of my own: Maybe if Apple would have chosen CDMA, they would have been able to have decent high-speed data with good battery life on their shiny little toy.
- Well, Apple now also launched the iPhone on time for the holiday season 2007 in European countries like the UK or Germany, expected in France soon. They hadn't been able to do so if they had chosen IS-95, which is never heart of in most parts of the world. Since Apple wants to gain market share aggressively, GSM is their only option.--65.241.15.227 01:39, 10 October 2007 (UTC)
- Yes, the German (Austria, Germany, Switzerland) Wikipedia explains that "GSM Phone" is just another word for "Mobile Phone"
and the article doesn't mention other standards. Mobiltelefon--68.6.44.232 16:09, 10 October 2007 (UTC)Ein [= "a"] Mobiltelefon (auch [= "also"] Handy, Funktelefon, GSM-Telefon, Funker, in der Schweiz auch Natel) ist …
In any case, these are marketing issues, and I'd prefer to keep this article about technical issues, especially since marketing of cellular phones is so drastically different between continents. --Mdwyer 19:03, 12 January 2007 (UTC)
[edit] Network Effect
iPhone and other GSM users will be able to use their handsets in Air France's inflight full mobile phone service:
CDMA phones will not work.
Flight companies of course will select GSM, because they target over 80 % over their global flight guests with it.
So if I want my device to work in airplanes, I better follow Apple and build a GSM device. --65.241.15.227 (talk) 22:08, 3 April 2008 (UTC)
[edit] GSM interference with audio devices
Under cons of GSM, it says that it interferes with audio devices. But then it says "3G uses W-CDMA now." How is that relevent?? Fresheneesz 02:07, 20 August 2007 (UTC)
- TDMA signals turn on and off about 50 times a second. This shows up as a 50hz noize in unshielded electronics -- especially amplifiers. CDMA signals are always on, and so they do not interfere in this particular way. Many people consider that particular interference to unique to GSM. It isn't. It is a feature of TDMA, and when GSM moves to its next generation, they will no longer be using TDMA, and GSM phones will no longer cause that terrible noise. Does that help? --Mdwyer 17:01, 20 August 2007 (UTC)
[edit] What audio codec is used?
Which codec and at what bitrate are these various standards sending audio? Might be worthwhile to add to the article (since I'm curious to know). - Theaveng 19:38, 24 September 2007 (UTC)
- CDMA (IS-95) uses the Enhanced Variable Rate Codec, which runs from about 8kb/s to as low as 800bytes/s. GSM (2G) appears to use a number of codecs, (see GSM) which range from 13kb/s to 1.8kb/s.
- Although it looks like CDMA is the clear winner, it is important to note that EVRC is not intended to transmit understandable speech at that rate. The full story must always take into account the quality of the transmitted signal. It might be best to direct you to the GSM or List of codecs articles. --Mdwyer 19:17, 10 October 2007 (UTC)
[edit] Spectral efficiency comparison table
Please feel free to add more mobile phone standards to the Spectral efficiency comparison table. Mange01 (talk) 15:58, 24 January 2008 (UTC)
