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GSM 1900Mhz Vs. CDMA 1900Mhz

Discussion in 'GENERAL Wireless Discussion' started by Guest, Jun 10, 2002.

  1. Rasputin

    Rasputin Bronze Senior Member
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    The problem you run into is in the freq. group planning, As they group the freqs a,b,c,d,e,f,g if you overlap too much on a GSM/TDMA system then a A group could hear another A group this is a big problem it causes direct interference the GSM/TDMA phone can not cancel out the other cell site on the same freq group it just picks up the interference. That is why you try to overlap as little as possible, sometimes when you add microcells they have fewer channels so you overlap more, normally because that microcell is filling in a gap, or to handle excess traffic.
     
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  2. Guest

    Guest Guest

    rasputin,

    well you sound credible when talking about the cdma technology and how it compares with gsm. my own opinion is that cdma is better technology and it sounds like you are partial that way as well. do you expect cdma to become more popular as the technology proves itself over time? why do you think gsm has so much marketshare worldwide? would you put your money in qualcomm stock??
     
  3. Guest

    Guest Guest

    They both require about the same. CDMA technology came from the US military. We used it on microwave shots back to headquater units in the field. Also we used WCDMA on satcom radios. The orginall idea on CDMA technology was that the theory said that there could be an infinite amount of users on one cell site. Well Sprint PCS found out the hard way....this is not true. See CDMA splits up the power equally between all of the users on that tower. So in essence as more subs are talking on a cell site, the less coverage that area has (i.e. coverage begins to shrink). CDMA was not designed for a whole bunch of individual radios out there running around. The benifits that it does off is that they only need limited spectrum and handoffs are alot softer. The benfits to GSM is that it has been around a lot longer, the standards have been set...and they work. CDMA...is still fairly new, and standards have not been set fully. GSM is also used world wide, where CDMA is used in the US and South Korea, with a few pockets here and there. I am an advocate of GSM, but don't get me wrong CDMA is a great technology...my thoughts are that Qualcomm...pushed to get it out the door to soon. If they would of waited...it would of been better. The one thing I love about GSM is the SIM card. The SIM stores all of your phone numbers and personal info. SO changing phones is a snap. You do not have to use your laptop to transfer your info or have a sales rep do it for you.
     
  4. Airb330

    Airb330 Silver Senior Member
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    Rasputin, a very good answer to the no internal CDMA antenna's. Thanks Bobolito for asking, maybe some day we will find a true 100% correct answer. Check out the Nokia 3585 on phonescoop.com According to it, it has 2 antenna's, an internal and pull-out. Sounds cool......drool, I want that phone.
     
  5. Rasputin

    Rasputin Bronze Senior Member
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    A little bit of knowledge does not go a long way.

    Sprint/Verizon/Qualcomm/Pacbell Wireless/GTE Wireless/Bell Atlantic they all tested this product to hell and back, it was never or never built to handle an infinite number of conversations. The word you used was in Theory, by controlling the power of the handsets so the RX power at the cellsite is the same, is one of the many things that makes it different from the Military technology. The number of maximum a channel can hold is something like 64 to 128 depending on the vocoder rate which is variable (depending on the speed of the talker). As far as shinking coverage that is pretty small and normally is not too much of a problem because you overlap the cell sites soo much, which you do as little as possible in GSM. The Reallity of GSM vs. CDMA is capacity and a CDMA has upwards of 3/4 times the capacity and that double with a 1x upgrade. Qualcomm did not push the product out the door too soon it has been on the streets since 92 with Pacbell Wireless/Bell Atlantic/GTE wireless. Sprints problems have been are more of holes in coverage because they are building a system from the ground up, and are still in the process dealling with the Not in My Backyard groups, and the permit process from a city can be very slow. At the end of the day the Sprint CDMA system will have the capacity for more users, that is why Voicestream needs more capacity in NYC and other metro areas, the current freqs they have will not do for the next 5 years, Sprint on the other hand is only at less then 50% capacity and as customers move to the 1x system the capacity is doubling.

    But that is just my 2 cents
     
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  6. Guest

    Guest Guest

    Everyone on this thread sounds like every other dealer out there talking about how their technology is better. Doesn't anyone else see that if you buy a block of spectrum, it is only BETTER FOR THE CARRIER TO FIT MORE CALLS IN EACH CHANNEL? Do some more research and stop listening to the advocates on either side.

    The reasons that CDMA has had problems gaining competitive advantage:
    1. GSM was established and adopted by countries, not just companies, well before QualComm came around.
    2. Because the original RTT system was in its infancy, they had to incorporate the old AMPS technology into the phones. Answer this question: would Nokia and Motorola rather manufacture a phone in which they have to
    a) support 1 air interface technology, or
    b) support 2 air interface technologies?

    So which phone is going to be more expensive to manufacture?

    3. If you manufacture the actual radio transceivers and software to manage all of the calls, would you spend the same amount on research and development for two different technologies, one for which you will sell 200 million units, and the other for which you sell 2 million because only 1 company is buying it?
    If you did, for those of you who have calcuators out there, which of these choices offers a greater return on investment?

    Hmmm? HMMMMMMM? Sorry, I didn't hear what you said. You're breaking up... I must be in a bad cell...

    Why do you think that 1xRTT (or CDMA2000) phones are so much more expensive? The per-phone cost of developing the 1x phone is greater than the EGSM because the R&D, focus groups, and Johan the Finnish electrical engineer's retirement benefits are the same. It's all about the margins and number of people within the POP, baby...

    Think about it from a business perspective rather than a technology perspective. Better technologies have not always won. Need I remind anyone of VCRs and BetaMax?

    However, if you are really interested in the paths to UMTS (both a hardware and software - the new software that's out today actually puts EGSM ahead of CDMA2000 in terms of the number of simultaneous calls), check out www.rysavy.com. Specifically the study entitled "Voice Capacity Enhancements for GSM Evolution to UMTS" at http://www.rysavy.com/Articles/GSM_voice_capacity_71802.pdf

    It was just published at the end of July.

    Listen, I used to sell VoiceStream, I have had CellularOne, AT&T (TDMA1900), and I did some work out at SprintPCS while I was working for one of the "Big 5" last year in management consulting. And you know what I learned? It's a freaking wireless phone, and calls drop off!!! It's that simple! Deal with it. I meet people all day long who don't know the difference between DSL and DOCSIS!!! They don't care.

    You can't differentiate your product based upon the technology!!! NO ONE CARES!! It is frustrating that most of the world can't understand a thing you guys are writing about. They are the human equivalent of navel lint. Once you realize that, live it, breathe it, the happier you will be.

    I was flipping through channels the other day on the radio and this chick here in Chicago was on the air talking about how all the radio waves coming from the cellular phone towers are giving everyone cancer!!! Does she not realize that it is the same technology that is being used to transmit her pinko-Commie blather? It's only a different frequency? I wanted to call up and ask her if she wears tin-foil on the inside of a hat on her head because THEY might be trying to read and control her mind... and then I wanted to ask her if she's been taking her freaking medication lately.

    Friends, people use AOL becuase it is EASY!!! They are cattle!

    Do you like your wireless phone? Do you like your provider? Great. I hook up my v60 and surf the web faster than I used to dial up. So what? The only important thing in my mind write now is, who am I going to bang this next weekend?

    Can you hear me now? Good.
     
  7. IdiOTeQnoLogY

    IdiOTeQnoLogY Bronze Senior Member
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    nice little rant there. take a deep breath and swallow that prozac.....good good boy.

    however, the fact that we like to have some healthy and sometimes heated discussion of network technologies is not a problem; like you seem to have with it.

    you need to chill out, have a few beers, and lighten up.

    some people like debating politics, some like debating cooking techniques, some like debating technology. it's ok man, trust me.... go with it. if talking technology is not for you then dont join in, simple..... we weren't bothering anybody...well maybe except for you.
     
  8. bobolito

    bobolito Diamond Senior Member
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    Live on Pay Per View! The enternal battle! On the ring: GSM vs CDMA!
     
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  9. ehcruzan

    ehcruzan Bronze Senior Member
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    Nicely done Idiot.....he was getting a bit carried away.
     
  10. ehcruzan

    ehcruzan Bronze Senior Member
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    Who's the referee Bobolito? [​IMG]
     
  11. Guest

    Guest Guest

    isnt the advantage of TDMA supposed to be the quality of signal where u have 3 people talking as opposed to 10 users?
     
  12. Guest

    Guest Guest

    what about a GAIT fon like the Seimens s46? u can rock on TDMA and GSM.
     
  13. emag0rad

    emag0rad Senior Member
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    Except that the S46 is not a GAIT phone.
     
  14. emag0rad

    emag0rad Senior Member
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    * It benefits the customer as well when a carrier can fit more calls in a given amount of spectrum - ever have "fast busies" or receive the message "Network Busy"?
    * The best technology does not always win (Beta was superior to VHS).
    * Take "Voice Capacity Enhancements for GSM Evolution to UMTS" with a grain of salt, lime and tequlla - many of those enhancements may bring GSM parity with current cdma2000 implementations specifically with regard to voice capacity but certainly not real world data rates.
    * Forget about widespread W-CDMA adoption in the U.S. for the foreseeable future - it requires 10 MHz of clear spectrum
    * The only point I agree with you is that average wireless customer could care less about the technology she is using but rather cares about quality of network and customer service and coverage.
    * blah, blah, blah....
     
  15. pfp

    pfp Senior Member
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    Figure this one will be a quick one to answer, just wanna make sure I did my homework:

    The S46 is NOT a GAIT phone because it doesn't have Analog to fall back on, which is one of the inherent advantages of TDMA phones that carries over to GAIT.

    Am I right???

    P

    <edit: added the following>

    Also, gait functions like both TDMA and GSM, whereas the s46 won't be as good as two separate phones, a gait phone will..

    Still on target?

    P
     
  16. emag0rad

    emag0rad Senior Member
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    Pretty much. Plus GAIT SIMS are different from standard SIMS. Also, in order for a GAIT phone to work properly, the carrier's TDMA network must have special GAIT network equipment installed in order to communicate properly the carrier's GSM networks.
     
  17. ZaphodB

    ZaphodB Signal Go Down De Hole...
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    GAIT is the fusion of GSM (hence the G) and ANSI-136 (hence the A). The I is for Interoperability.

    GSM everybody knows.
    ANSI-136 is (to oversimplify) TDMA with AMPS (analog) backup.

    An unshackled GAIT phone would choose one technology (you can program it to choose GSM or TDMA as its primary technology), let's say GSM. If there were no GSM signal, it would switch to TDMA. In the absence of either it would remain on the TDMA 'half' and use AMPS. In phase 1 of GAIT there is no GSM->TDMA (or vice versa) handoff. That's a future enhancement, consistent with the ultimate goal of GAIT as a seamless meld of GSM and ANSI-136.
     
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  18. pfp

    pfp Senior Member
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    So, in addition to trying to totally switch to GSM, Cingular has to alter the hardware of TDMA towers anyway just to accept GAIT??? oh god....Why do the network's need to cross communicate? I'd


    You mean in-call handoff, right, so the user wouldn't lose a conversation. They are working on this???
    Sweet

    P
     
  19. ZaphodB

    ZaphodB Signal Go Down De Hole...
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    Not quite. Let's take the two scenarios. First, you need to know how your NSDB (network selection database) is set up. It can be set up so that you have GSM as your 'home', or so that you have ANSI-136 (TDMA/AMPS) as your 'home'. There are a bunch of configurations that can be done (look for the provider's ANSI-136 before accepting a 'roaming' GSM signal, etc.) and you end up with a list sorted by priority.

    Scenario #1: You are on a GSM network with your GAIT phone. Currently, a GSM tower has 3 possible 'categories':

    Home - the GAIT phone selects this immediately.
    Preferred - the GAIT phone selects this and scans behind the scenes for a selection higher on the list.
    Forbidden - you can make emergency calls only, and the phone scans behind the scenes for the highest possible selection on the list.

    Scenario #2: You are on an ANSI-136 network. ANSI-136 networks have 5 categories:

    Home - selects immediately.
    Partner - takes a while to select but no background scanning.
    Favoured - select the highest on the list, but do background scanning for something higher.
    Neutral - background scanning for something higher on the list - even if it's Favoured.
    Forbidden - emergency calls only, continual background scanning.

    There are (as of now) no plans for in-call handoff, but it is a 'desired enhancement'. It won't be done in Phase 1, and Phase 2 is still on the design board. I strongly suspect that by the time GAIT-2 gets off the ground, AT&T and Cingular (the only TDMA providers in the US) will long since have converted their networks to GSM, thus rendering GAIT-2 useless.
     
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  20. emag0rad

    emag0rad Senior Member
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  21. VPNGSM

    VPNGSM New Member

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    So, why are you saying that an ATTWS Siemens S46 is not a GAIT phone??? Are you saying that handoffs are not beign completed? Have you ever used the Siemens in the Tristate area? It switches to TDMA in non-GSM areas. Although there are times when it appears to lose registration in the handoff, and the programming in TDMA only may become necessary to update the HLR and receive incoming calls directly. But, alot of the time it appears to work fine as it searches for GSM as the primary and TDMA as the secondary.
     
  22. emag0rad

    emag0rad Senior Member
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    The S46 is not a GAIT phone and if it were it wouldn't work as a GAIT phone on AT&T's netwoerks because AT&T does not have GAIT equipment installed in its network (re-read my previous post). A GAIT phone requires a GAIT SIM and and GAIT phone must also support Analog which the S46 does not. Switching between technologies while a call is not in progress is not a "hand-off", it is just registering with a different network using a different technology.
     

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