tmobile is trash

Umm, get your facts strait, also CDMA is less affected by Noise and Low signal. They only require 200 Miliwatts transmitting power vs. GSM 1 Watt, in theory CDMA is safer because it uses less power. Visit http://www.ccs.neu.edu/home/futrelle/teaching/com1204sp2001/uwash-intr o/final.html
if you know how to. I will also post a quote,
CDMA

CDMA stands for "code division multiple access" and is both the most interesting and the hardest to implement multiplexing method. CDMA has been likened to a party: When everyone talks at once, no one can be understood, however, if everyone speaks a different language, then they can be understood. CDMA systems have no channels, but instead encodes each call as a coded sequence across the entire frequency spectrum. Each conversation is modulated, in the digital domain, with a unique code (called a pseudo-noise code) that makes it distinguishable from the other calls in the frequency spectrum. Using a correlation calculation and the code the call was encoded with, the digital audio signal can be extracted from the other signals being broadcast by other phones on the network. From the perspective of one call, upon extracting the signal, everything else appears to be low-level noise. As long as there is sufficient separation between the codes (said to be mutually orthogonal), the noise level will be low enough to recover the digital signal. Each signal is not, in fact, spread across the whole spectrum (12.5 MHz for traditional cellular or 60 MHz in PCS cellular), but is spread across 1.25 MHz "pass-bands."

CDMA systems are the latest technology on the market and are already eclipsing TDMA in terms of cost and call quality. Since CDMA offers far greater capacity and variable data rates depending on the audio activity, many more users can be fit into a given frequency spectrum and higher audio quality can be provide. The current CDMA systems boast at least three times the capacity of TDMA and GSM systems. The fact that CDMA shares frequencies with neighboring cell towers allows for easier installation of extra capacity, since extra capacity can be achieved by simply adding extra cell sites and shrinking power levels of nearby sites. CDMA technology also allows lower cell phone power levels (200 miliwatts) since the modulation techniques expect to deal with noise and are well suited to weaker signals. The downside to CDMA is the complexity of deciphering and extracting the received signals, especially if there are multiple signal paths (reflections) between the phone and the cell tower (called multipath interference). As a result, CDMA phones are twice as expensive as TDMA phones and CDMA cell site equipment is 3-4 times the price of TDMA equivalents.

GSM is the latest technology and the easyest to work with. GSM hold more i did a 4 year study on it in college.

No it dosent, Actualy CDMA is the latest technology, Developed later than GSM in America. TDMA was before those. You must have had a bad teacher. I worked for T-Mobile and Verizon as a Technical Engineer. CDMA penetrates farther than GSM also and is ALOT safer in terms of radiation. Also CDMA proves better call quality especialy when jumping from tower to tower.

Last edited by Erris on Wed Jan 25, 2006 12:19 am, edited 1 time in total

There is avery nice article here comparing CDMA to TDMA(GSM)
http://www.mouthshut.com/review/GSM_Mobile_Technology_Vs_CDMA_Mobile_T echnology-65504-1.html

The gist of it comes to this:

GSM:
Voice quality far better than CDMA

CDMA:
Has a soft capacity limit - means increasing the number of users will decrease system performance

The rest of the specs are comparable with one or the other leading a bit here and there, but where one leads the other one comes with somethign to chatch up.

That said GSM providers are expected to switch to WCDMA, they still can use their existing GSM network. So users won't feel anything special when the operators shift to the new cell generation (3G), independently from the technology they choose.

Data transfer: CDMA uses EVDO standard and GSM use EDGE.
In the case of EVDO, theoretical high traffic can degrade speed and performance, while the EDGE network is more susceptible to interference. Both require being within close range of a cell to get the best speeds, while performance decreases with distance.
EVDO can theoretically provide faster transfer rates. After the GSM providers move to WCDMA their transfer rates will get on par with EVDO.

Roaming: For the most part, both networks have fairly concentrated coverage in major cities and along major highways. GSM carriers, however, have roaming contracts with other GSM carriers, allowing wider coverage of more rural areas, generally speaking, often without roaming charges to the customer. CDMA networks may not cover rural areas as well as GSM carriers, and though they may contract with GSM cells for roaming in more rural areas, the charge to the customer will generally be significantly higher.

International Roaming: If you need to make calls to other countries, a GSM carrier can offer international roaming, as GSM networks dominate the world market. If you travel to other countries you can even use your GSM cell phone abroad, providing it is a quad-band phone (850/900/1800/1900 MHz). By purchasing a SIM card with minutes and a local number in the country you are visiting, you can make calls against the card to save yourself international roaming charges from your carrier back home. CDMA phones that are not card-enabled do not have this capability.

edit:spelling.

thanx Erris

Umm actualy CDMA has better call quality, especialy if you are switching from tower to towe, if you didnt know CDMA uses a Soft Hand Off and GSM uses a Hard Hand off, in turn creates MORE dropped calls. Actualy also CDMA has more roaming, look at all the CDMA carriers, Verizon, Sprint, AllTel, Cell South, and lots more.

although CDMA is transferred via code, it does not give better call quality. GSM seperates users into time, which does not cause interference between users. unlike spread spectrum technology, where interference can be caused by many users occupying the same band.

GSM also provides better battery life for talk time/standby since the device is only transmitting a portion of the time (1/3 to 1/10) during converstaions.

locust, i think you might be thinking of multipath distortion in regards to call quality and most of the bugs with hard hand offs were left behind with tdma.

UMTS will also allow users to access voice and data at the same time which allows video conferencing/checking email while talking to business partners, etc. EVDO does not allow this as it is data only. And once the HSDPA software upgrade is initialized, the speeds will beat EVDO.

More countries are starting to use it, like China, I went to China and has great roaming on my Verizon Phone

tmobile is trash

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