Gsm Vs Cdma

Which Technology is better:

GSM

or

CDMA?

B efore deciding which technology is superior, let’s talk a little more about these two technologies: CDMA:

stands for Code Division Multiple Access. Both data and voice

are separated from signals using codes and then transmitted using a wide frequency range. Because of this, there are more space left for data transfer (this was one of the reasons why CDMA is the preferred technology for the 3G generation, which is broadband access and the use of big multimedia messages). 14% of the worldwide market goes to CDMA. For the 3G generation CDMA uses 1x EV-DO and EV-DV. It has a lot of users in Asia, specially in South Korea.

GSM: stands for Global System Mobile. Even though it is sold as “the latest technology” in several countries, this technology is older than CDMA (and also TDMA). But keep in mind that this doesn’t mean that GSM is inferior or worse than CDMA. Roaming readiness and fraud prevention are two major advantages from this technology. GSM is the most used cell phone technology in the world, with 73% of the worldwide market. It has a very strong presence in Europe.

TDMA technology is the less used from the three main digital technologies (GSM, CDMA and TDMA) and we think it will gradually be replaced to CDMA or GSM. That’s why the GSM vs CDMA war. At one corner, GSM operators say it is better “because it uses a SIM chip, it is the most used technology worldwide, it is more secure and it is more advanced”. On the 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...” But which one of these statements are correct? Accordingly to Nokia, “this discussion is not about technology anymore, but about market”. We think this is the best way to describe the war between these two cell phone technologies. In the beginning, GSM was in fact superior. It had more services and allowed more data transfer. But CDMA, facing the advantages of the competitor standard, soon delivered the same features found on GSM. Nowadays, it is not possible to say that GSM services are better than CDMA. Multimedia mes-

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sages, video, high-speed Internet access, digital camera and even PDA function are some of the features we can found on both technologies. The new CDMA 1XRTT technology, which previews what G3 cell phones will bring, is more advanced than EDGE, technology from the beginning of 3G generation, allowing higher transfer rates. Even the GSM SIM card advantage, that allows you to change your cell phone and keep your phone list, is being surplaced by some CDMA operators with a service that allows you to store your phone book on the operator’s database, allowing you to recover your phone book even if your cell phone is stolen (which is not possible with GSM, since if your cell phone is stolen, your SIM card will be stolen together). Notice that recently 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. So, nowadays both technologies are equiparated in technology, but this picture won’t be like that in the future. After all, CDMA evolution ground is wider and in a few years it will be superior than GSM. This means that GSM operators will disappear? Not at all. They will migrate over CDMA and the war will continue, because the existing CDMA operators chose to use 1xEV-DO and1XEV-DV technologies for their 3G network and the existing GSM operators have opted for a different technology, called WCDMA. Also, even though the current GSM operators will migrate 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.

What is the Difference Between GSM and CDMA?

C ellular service there are two main competing network technologies: Global System for Mobile Communications (GSM) and Code Division Multiple Access (CDMA). Cellular carriers including Sprint PCS, Cingular Wireless, Verizon and T-Mobile use one or the other. Understanding the difference between GSM and CDMA will allow you to choose a carrier that uses the preferable network technology for your needs. The GSM Association is an international organization found-

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.

Subscriber Identity Module (SIM) cards: In the United

ed in 1987, dedicated to providing, developing, and overseeing the worldwide wireless standard of GSM. CDMA, a proprietary standard designed by Qualcomm in the United States, has been the dominant network standard for North America and parts of Asia. However, GSM networks continue to make inroads in the United States, as CDMA networks make progress in other parts of the world. There are camps on both sides that firmly believe either GSM or CDMA architecture is superior to the other. That said, to the non-invested consumer who simply wants bottom line information to make a choice, the following considerations may be helpful.

Coverage:

The most important factor is getting service in the areas you

will be using your phone. Upon viewing competitors’ coverage maps you may discover that only GSM or CDMA carriers offer cellular service in your area. If so, there is no decision to be made, but most people will find that they do have a choice.

Data Transfer Speed:

With the advent of cellular phones doing double

and triple duty as streaming video devices, podcast receivers and email devices, speed is important to those who use the phone for more than making calls. CDMA has been traditionally faster than GSM, though both technologies continue to rapidly leapfrog along this path. Both boast “3G” standards, or 3rd generation technologies.

EVDO, also known as CDMA2000, is CDMA’s answer to the need for speed with a downstream rate of about 2 megabits per second, though some reports suggest real world speeds are closer to 300-700 kilobits per second (kbps). This is comparable 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. GSM’s answer is EDGE (Enhanced Data Rates for GSM Evolution), which boasts data rates of up to 384 kbps with real world speeds reported closer to 70-140 kbps. With added technologies still in the works that include UMTS (Universal Mobile Telephone Standard) and HSDPA (High Speed Downlink Packet Access), speeds reportedly increase to about 275—380 kbps. This technology is also known as W-CDMA, but is incompatible with CDMA networks. An EDGE-ready phone is required.

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 GSM carrier. The CDMA equivalent, a R-UIM card, is only available in parts of Asia but remains on the horizon for the U.S. market. CDMA carriers in the U.S. require proprietary handsets that are linked to one carrier only and are not card-enabled. To upgrade a CDMA phone, the carrier must deactivate the old phone then activate the new one. The old phone becomes useless.

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, however there are several countries that use CDMA networks. Check with your CDMA provider for your specific requirements. According CDG.org, CDMA networks support over 270 million subscribers worldwide, while GSM.org tallies up their score at over 1 billion. As CDMA phones become R-UIM enabled and roaming contracts between networks improve, integration of the standards might eventually make differences all but transparent to the consumer. The chief GSM carriers in the United States are Cingular Wireless, recently merged with AT&T Wireless, and T-Mobile USA. Major CDMA carriers are Sprint PCS, Verizon and Virgin Mobile. There are also several smaller cellular companies on both networks.

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What is CDMA? C ode division multiple access (CDMA) is a channel access method utilized by various radio communication technologies. It should not be confused with cdmaOne (often referred to as simply “CDMA”), which is a mobile phone standard that uses CDMA as its underlying channel access method. CDMA employs spread-spectrum technology and a special coding scheme (where each transmitter is assigned a code) to allow multiple users to be multiplexed over the same physical channel. By contrast, time division multiple access (TDMA) divides access by time, while frequency-division multiple access (FDMA) divides it by frequency. CDMA is a form of “spreadspectrum” signaling, since the modulated coded signal has a much higher bandwidth than the data being communicated. An analogy to the problem of multiple access is a room (channel) in which people wish to communicate with each other. To avoid confusion, people could take turns speaking (time division), speak at different pitches (frequency division), or speak in different directions (spatial division). In CDMA, they would speak different languages. People speaking the same language can understand each other, but not other people. Similarly, in radio CDMA, each group of users is given a shared code. Many codes occupy the same channel, but only users associated with a particular code can understand each other. CDMA has been used in many communications and navigation systems, including the Global Positioning System and the OmniTRACS satellite system for transportation logistics.

What is GSM?

G lobal System for Mobile communications (GSM: originally from Groupe Spécial Mobile) is the most popular standard for mobile phones in the world. Its promoter, the GSM Association, 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 quality, 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 Partnership Project (3GPP). The GSM logo is used to identify compatible handsets and equipment The ubiquity of the GSM standard has been advantageous to both consumers (who benefit from the ability to roam and switch carriers without switching phones) and also to

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network operators (who can choose equipment from any of the many vendors implementing GSM). GSM also pioneered a low-cost alternative to voice calls, the Short message service (SMS, also called “text messaging”), which is now supported on other mobile standards as well. Newer versions of the standard were backward-compatible with the original GSM phones. For example, Release ‘97 of the standard added packet data capabilities, by means of General Packet Radio Service (GPRS). Release ‘99 introduced higher speed data transmission using Enhanced Data Rates for GSM Evolution (EDGE).

Which phone will it work when I travel?

O ne big question about getting a phone with QWERTY keyboard (or “pager” as we call them), is “Will it work when I travel?” The answer will depend on the type of pager you have, the pager’s wireless network type, the carrier you have, and where you are traveling. Answers will vary from “no”, “yes”, to “you will need to rent”, and even “it will cost you lots of money”, and so forth. Generally speaking, GSM/GPRS is the major international standard. GSM is used in 860 networks in 220 countries throughout the world. The only problem is that in the US/Canada, 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 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. CDMA (1xRTT, EVDO), while very popular in the US/Canada, is

less popular internationally. Your CDMA pager will probably only work within South Korea, and a couple of other places mainly in the Asiatic area. There are some dual radio phones for the CDMA carriers in the US (Sprint/Verizon) that also have a GSM radio/SIM card slot for use when roaming internationally. In this article I will review the major carriers that DeafPagers. com offers pagers from, and summarize what their interna-

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 roaming support. Most T-Mobile devices are able to work worldwide. More specifically, 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”

C

ingular uses the GSM/GPRS standard, so there is a very good chance devices you are using under Cingular will be able to work worldwide in more than 190 countries. More specifically, 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 Cingular such as the BlackBerry 8800, 8700c, Samsung BlackJack, and Treo 680 & 750 will work internationally. Cingular also offers roaming on cruise ships. Cingular will let you rent a phone if you’re going to a country such as South Korea or Japan that do not have GSM coverage. For more information regarding Cingular’s international coverage,

Verizon Wireless Verizon uses the CDMA standard for its BroadbandAccess (EVDO) phones, like Sprint. This CDMA standard does not have the global reach of the GSM/GPRS standard, but there are some areas internationally that do work with this carrier’s phones. Popular devices available through Verizon such as the BlackBerry 8700v, Treo 700wx, and Motorola Q can be used in certain areas internationally. Verizon also has a GSM phone rental service for international travelers whose Verizon phone does not work in their destinations. Verizon also offers some special “Global Phones” that have both CDMA and GSM modes which allow you to use the GSM coverage internationally. Verizon’s international services website has a good overview of what they have to offer internationally. If you want to learn more about your roaming choices, visit Verizon’s international roaming coverage website. Verizon’s roaming covers a good assortment of cruise ships as well. Additionally, here is information regarding Verizon’s international rental program, which is quite extensive, offering international phones, Japanese cell phones, Satellite phones, and international 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: Sprint

It really does not matter what type of pager you get for traveling internationally, 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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