GSM or CDMA? by xcu16608

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									                                       Which Technology is better:


                        GSM                                               or        CDMA?
                                                                                        sages, video, high-speed Internet access, digital camera and
     B efore deciding which technology is                                               even PDA function are some of the features we can found on
                                                                                        both technologies. The new CDMA 1XRTT technology, which
     superior, let’s talk a little more about                                           previews what G3 cell phones will bring, is more advanced
                                                                                        than EDGE, technology from the beginning of 3G generation,
     these two technologies:                                                            allowing higher transfer rates.

                                                                                        Even the GSM SIM card advantage, that allows you to change
     CDMA:          stands for Code Division Multiple Access. Both data and voice       your cell phone and keep your phone list, is being surplaced
     are separated from signals using codes and then transmitted using a wide fre-      by some CDMA operators with a service that allows you to
     quency range. Because of this, there are more space left for data transfer (this   store your phone book on the operator’s database, allowing
     was one of the reasons why CDMA is the preferred technology for the 3G gen-        you to recover your phone book even if your cell phone is sto-
     eration, which is broadband access and the use of big multimedia messages).        len (which is not possible with GSM, since if your cell phone is
     14% of the worldwide market goes to CDMA. For the 3G generation CDMA uses          stolen, your SIM card will be stolen together). Notice that re-
     1x EV-DO and EV-DV. It has a lot of users in Asia, specially in South Korea.       cently a new accessory called SIM backup was released, which
                                                                                        allows you to backup the data stored in your SIM card. Also
                                                                                        some GSM operators are offering a similar backup service.
     GSM: stands for Global System Mobile. Even though it is sold as “the latest        So, nowadays both technologies are equiparated in technol-
     technology” in several countries, this technology is older than CDMA (and also     ogy, but this picture won’t be like that in the future. After all,
     TDMA). But keep in mind that this doesn’t mean that GSM is inferior or worse       CDMA evolution ground is wider and in a few years it will be
     than CDMA. Roaming readiness and fraud prevention are two major advantages         superior than GSM. This means that GSM operators will disap-
     from this technology. GSM is the most used cell phone technology in the world,     pear? Not at all. They will migrate over CDMA and the war will
     with 73% of the worldwide market. It has a very strong presence in Europe.         continue, because the existing CDMA operators chose to use
                                                                                        1xEV-DO and1XEV-DV technologies for their 3G network and
     TDMA technology is the less used from the three main digi-                         the existing GSM operators have opted for a different technol-
     tal technologies (GSM, CDMA and TDMA) and we think it will                         ogy, called WCDMA. Also, even though the current GSM op-
     gradually be replaced to CDMA or GSM. That’s why the GSM                           erators will migrate to WCDMA, they still can use their existing
     vs CDMA war. At one corner, GSM operators say it is better                         GSM network. So users won’t feel anything special when the
     “because it uses a SIM chip, it is the most used technology                        operators shift to the new cell generation (3G), independently
                                                           .
     worldwide, it is more secure and it is more advanced” On the                       from the technology they choose.
     other corner, CDMA followers say it is better “because it is the
     3G generation chosen technology and GSM will migrate to
     CDMA since CDMA is more advanced...”                                               What is the Difference Between
     But which one of these statements are correct? Accordingly                         GSM and CDMA?
     to Nokia, “this discussion is not about technology anymore,
     but about market” We think this is the best way to describe
                        .                                                               C ellular service there are two main competing network tech-
     the war between these two cell phone technologies.                                 nologies: Global System for Mobile Communications (GSM)
                                                                                        and Code Division Multiple Access (CDMA). Cellular carriers
     In the beginning, GSM was in fact superior. It had more ser-                       including Sprint PCS, Cingular Wireless, Verizon and T-Mobile
     vices and allowed more data transfer. But CDMA, facing the                         use one or the other. Understanding the difference between
     advantages of the competitor standard, soon delivered the                          GSM and CDMA will allow you to choose a carrier that uses
     same features found on GSM. Nowadays, it is not possible to                        the preferable network technology for your needs.
     say that GSM services are better than CDMA. Multimedia mes-                         The GSM Association is an international organization found-




MOBILE CHOICE - MARCH 1, 2008
                                             12
                                                                                      In the case of EVDO, theoretical high traffic can degrade speed
                                                                                      and performance, while the EDGE network is more suscepti-
                                                                                      ble to interference. Both require being within close range of a
                                                                                      cell to get the best speeds, while performance decreases with
                                                                                      distance.

                                                                                      Subscriber Identity Module (SIM) cards: In the United
                                                                                      States only GSM phones use SIM cards. The removable SIM
                                                                                      card allows phones to be instantly activated, interchanged,
                                                                                      swapped out and upgraded, all without carrier intervention.
                                                                                      The SIM itself is tied to the network, rather than the actual
                                                                                      phone. Phones that are card-enabled can be used with any
ed in 1987, dedicated to providing, developing, and oversee-                          GSM carrier.
ing the worldwide wireless standard of GSM. CDMA, a propri-                           The CDMA equivalent, a R-UIM card, is only available in parts
etary standard designed by Qualcomm in the United States,                             of Asia but remains on the horizon for the U.S. market. CDMA
has been the dominant network standard for North America                              carriers in the U.S. require proprietary handsets that are linked
and parts of Asia. However, GSM networks continue to make                             to one carrier only and are not card-enabled. To upgrade a
inroads in the United States, as CDMA networks make prog-                             CDMA phone, the carrier must deactivate the old phone then
ress in other parts of the world. There are camps on both sides                       activate the new one. The old phone becomes useless.
that firmly believe either GSM or CDMA architecture is supe-
rior to the other. That said, to the non-invested consumer who                        Roaming: For the most part, both networks have fairly con-
simply wants bottom line information to make a choice, the                            centrated coverage in major cities and along major highways.
following considerations may be helpful.                                              GSM carriers, however, have roaming contracts with other
                                                                                      GSM carriers, allowing wider coverage of more rural areas,
Coverage:        The most important factor is getting service in the areas you        generally speaking, often without roaming charges to the
will be using your phone. Upon viewing competitors’ coverage maps you may             customer. CDMA networks may not cover rural areas as well
discover that only GSM or CDMA carriers offer cellular service in your area. If so,   as GSM carriers, and though they may contract with GSM cells
there is no decision to be made, but most people will find that they do have a        for roaming in more rural areas, the charge to the customer
choice.                                                                               will generally be significantly higher.
                                                                                      International Roaming: If you need to make calls to other
Data Transfer Speed:           With the advent of cellular phones doing double        countries, a GSM carrier can offer international roaming, as
and triple duty as streaming video devices, podcast receivers and email de-           GSM networks dominate the world market. If you travel to
vices, speed is important to those who use the phone for more than making             other countries you can even use your GSM cell phone abroad,
calls. CDMA has been traditionally faster than GSM, though both technologies          providing it is a quad-band phone (850/900/1800/1900 MHz).
continue to rapidly leapfrog along this path. Both boast “3G” standards, or 3rd       By purchasing a SIM card with minutes and a local number in
generation technologies.                                                              the country you are visiting, you can make calls against the
                                                                                      card to save yourself international roaming charges from your
EVDO, also known as CDMA2000, is CDMA’s answer to the                                 carrier back home. CDMA phones that are not card-enabled
need for speed with a downstream rate of about 2 megabits                             do not have this capability, however there are several coun-
per second, though some reports suggest real world speeds                             tries that use CDMA networks. Check with your CDMA pro-
are closer to 300-700 kilobits per second (kbps). This is com-
                                                                                      vider for your specific requirements.
parable to basic DSL. As of fall 2005, EVDO is in the process of
being deployed. It is not available everywhere and requires a
phone that is CDMA2000 ready.                                                         According CDG.org, CDMA networks support over 270 million
                                                                                      subscribers worldwide, while GSM.org tallies up their score at
GSM’s answer is EDGE (Enhanced Data Rates for GSM Evo-                                over 1 billion. As CDMA phones become R-UIM enabled and
lution), which boasts data rates of up to 384 kbps with real                          roaming contracts between networks improve, integration
world speeds reported closer to 70-140 kbps. With added                               of the standards might eventually make differences all but
technologies still in the works that include UMTS (Universal                          transparent to the consumer.
Mobile Telephone Standard) and HSDPA (High Speed Down-                                The chief GSM carriers in the United States are Cingular Wire-
link Packet Access), speeds reportedly increase to about                              less, recently merged with AT&T Wireless, and T-Mobile USA.
275—380 kbps. This technology is also known as W-CDMA,                                Major CDMA carriers are Sprint PCS, Verizon and Virgin Mo-
but is incompatible with CDMA networks. An EDGE-ready                                 bile. There are also several smaller cellular companies on both
phone is required.                                                                    networks.




                                                                                                                                 MOBILE CHOICE - MARCH 1, 2008
                                                                                                                          13
     What is CDMA?                                                     network operators (who can choose equipment from any of
     C ode division multiple access (CDMA) is a channel access         the many vendors implementing GSM). GSM also pioneered a
     method utilized by various radio communication technolo-          low-cost alternative to voice calls, the Short message service
     gies. It should not be confused with cdmaOne (often referred      (SMS, also called “text messaging”), which is now supported
     to as simply “CDMA”), which is a mobile phone standard that       on other mobile standards as well.
     uses CDMA as its underlying channel access method.
     CDMA employs spread-spectrum technology and a special             Newer versions of the standard were backward-compatible
     coding scheme (where each transmitter is assigned a code) to      with the original GSM phones. For example, Release ‘97 of the
     allow multiple users to be multiplexed over the same physical     standard added packet data capabilities, by means of General
     channel. By contrast, time division multiple access (TDMA) di-    Packet Radio Service (GPRS). Release ‘99 introduced higher
     vides access by time, while frequency-division multiple access    speed data transmission using Enhanced Data Rates for GSM
     (FDMA) divides it by frequency. CDMA is a form of “spread-        Evolution (EDGE).
     spectrum” signaling, since the modulated coded signal has a
     much higher bandwidth than the data being communicated.
                                                                       Which phone will it work
     An analogy to the problem of multiple access is a room (chan-
     nel) in which people wish to communicate with each other.         when I travel?
     To avoid confusion, people could take turns speaking (time
     division), speak at different pitches (frequency division), or    O ne big question about getting a phone with QWERTY key-
     speak in different directions (spatial division). In CDMA, they   board (or “pager” as we call them), is “Will it work when I trav-
     would speak different languages. People speaking the same         el?” The answer will depend on the type of pager you have,
     language can understand each other, but not other people.         the pager’s wireless network type, the carrier you have, and
     Similarly, in radio CDMA, each group of users is given a shared                                                             ,
                                                                       where you are traveling. Answers will vary from “no” “yes” to ,
     code. Many codes occupy the same channel, but only users                                  ,
                                                                       “you will need to rent” and even “it will cost you lots of money”,
     associated with a particular code can understand each other.      and so forth.
                                                                       Generally speaking, GSM/GPRS is the major international stan-
     CDMA has been used in many communications and naviga-             dard. GSM is used in 860 networks in 220 countries through-
     tion systems, including the Global Positioning System and the     out the world. The only problem is that in the US/Canada,
     OmniTRACS satellite system for transportation logistics.          different frequencies are used (850/1900 MHz) than the rest
                                                                       of the world (900/1800 MHz), meaning your GSM pager will
                                                                       need to be at least tri, or preferably, quad band in order for it
     What is GSM?                                                      to even have a chance to work internationally. You can easily
                                                                       tell if your device is GSM if it requires a SIM card to work.
     G lobal System for Mobile communications (GSM: original-           CDMA (1xRTT, EVDO), while very popular in the US/Canada, is
     ly from Groupe Spécial Mobile) is the most popular standard
     for mobile phones in the world. Its promoter, the GSM Asso-
     ciation, estimates that 82% of the global mobile market uses
     the standard [1]. GSM is used by over 2 billion people across
     more than 212 countries and territories.[2][3] Its ubiquity
     makes international roaming very common between mobile
     phone operators, enabling subscribers to use their phones in
     many parts of the world. GSM differs from its predecessors in
     that both signaling and speech channels are digital call qual-
     ity, and so is considered a second generation (2G) mobile
     phone system. This has also meant that data communication
     was built into the system using the 3rd Generation Partner-       less popular internationally. Your CDMA pager will probably
     ship Project (3GPP).                                              only work within South Korea, and a couple of other places
     The GSM logo is used to identify compatible handsets and          mainly in the Asiatic area. There are some dual radio phones
     equipment                                                         for the CDMA carriers in the US (Sprint/Verizon) that also have
                                                                       a GSM radio/SIM card slot for use when roaming internation-
     The ubiquity of the GSM standard has been advantageous            ally.
     to both consumers (who benefit from the ability to roam           In this article I will review the major carriers that DeafPagers.
     and switch carriers without switching phones) and also to         com offers pagers from, and summarize what their interna-




MOBILE CHOICE - MARCH 1, 2008
                                   14
                                                                                    T-Mobile
                                                                                    T-Mobile uses the GSM/GPRS standard, and because they are owned by one of
                                                                                    the largest European carriers, Deutsche Telekom, they have excellent EU roam-
                                                                                    ing support. Most T-Mobile devices are able to work worldwide. More specifi-
                                                                                    cally, if your device has tri or quad band GSM, it will work internationally. Most
                                                                                    new phones these days include at least tri band GSM with support for higher
                                                                                    2.5 or 3G speeds (EDGE or HSPDA). Popular devices available through T-Mobile
                                                                                    such as the Sidekick 3, BlackBerry 8800, 8703g, and the Dash have quad-band
                                                                                    GSM. T-Mobile, like the other carriers here, allow you to rent a phone if you’re
tional coverage policies are.                                                       going to a country that isn’t covered by T-Mobile.
                                                                                    For more information regarding T-Mobile’s international coverage, click here.

Cingular Wireless/”the New AT&T”
                                                                                    Verizon Wireless
C    ingular uses the GSM/GPRS standard, so there is a very                         Verizon uses the CDMA standard for its BroadbandAccess (EVDO) phones, like
good chance devices you are using under Cingular will be                            Sprint. This CDMA standard does not have the global reach of the GSM/GPRS
able to work worldwide in more than 190 countries. More spe-                        standard, but there are some areas internationally that do work with this car-
cifically, if your device has tri or quad band GSM, it will work                    rier’s phones. Popular devices available through Verizon such as the BlackBerry
internationally. Most new phones these days include at least                        8700v, Treo 700wx, and Motorola Q can be used in certain areas internationally.
tri band GSM with support for higher 2.5 or 3G speeds (EDGE                         Verizon also has a GSM phone rental service for international travelers whose
or HSPDA). Popular devices available through Cingular such                          Verizon phone does not work in their destinations. Verizon also offers some spe-
as the BlackBerry 8800, 8700c, Samsung BlackJack, and Treo                          cial “Global Phones” that have both CDMA and GSM modes which allow you to
680 & 750 will work internationally. Cingular also offers roam-                     use the GSM coverage internationally.
ing on cruise ships. Cingular will let you rent a phone if you’re                   Verizon’s international services website has a good overview of what they have
going to a country such as South Korea or Japan that do not                         to offer internationally. If you want to learn more about your roaming choices,
have GSM coverage.                                                                  visit Verizon’s international roaming coverage website. Verizon’s roaming cov-
For more information regarding Cingular’s international cov-                        ers a good assortment of cruise ships as well. Additionally, here is information
erage,                                                                              regarding Verizon’s international rental program, which is quite extensive, offer-
                                                                                    ing international phones, Japanese cell phones, Satellite phones, and interna-
                                                                                    tional BlackBerries for rent or purchase.


                                                                                    Coverage:
                                                                                    CDMA: To see where you can roam globally with a CDMA pager, visit this link.
                                                                                    GSM: To see where you can roam globally with a GSM pager, visit this link For
                                                                                    more specific coverage information and carriers for a particular country, visit
                                                                                    this link.
                                                                                    If you want more information regarding international roaming for the six major
                                                                                    US carriers, visit this link, but be warned, the last update to this site was March
                                                                                    2004. You may get better information from the links listed above under specific
                                                                                    carriers.


                                                                                    Recommendations:
                                                                                    It really does not matter what type of pager you get for traveling internation-
Sprint                                                                              ally, as long as it has quad-band GSM with dual-band UMTS/HSDPA. However,
Sprint uses the CDMA standard for its Vision (1xRTT) and Power Vision(EVDO)         it’s been our experience that the most popular pager here in the US is also a
offerings in the US. This CDMA standard does not have the global reach of the       great choice especially if you plan to travel to Europe extensively - and that is
GSM/GPRS standard, but there are some areas in ternationally that do work with      the T-Mobile Sidekick 3. It works very well, and you do not even have to get an
this carrier’s phones, such as Canada, Mexico, China, India, several countries in   international SIM card.
south-east Asia, some countries in central/south America, and some islands in       Be warned! If you want to avoid excess data/roaming charges, you may want
the Carribean. Popular devices available through Sprint such as the Treo 700p,      to consider getting or renting a different phone while you travel, so that your
700wx, and BlackBerry 8705e, will work internationally. However Sprint has GSM      US friends do not text/page/IM you all the time while you are abroad. It’s not as
phones that you can rent if you are going to an international destination that      cheap as it is here to stay connected to AIM all the time!
does not have CDMA coverage.
For more information regarding Sprint’s international coverage, click here.         Design created by Sergiy Burtovyy - rebruary 21. 2008.




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