GSM Vs. CDMA: What Is The Difference And Which Is
Better?
Most cell phone owners around the
world only have to worry about a single carrier technology called the Global
System for Mobile Communications, or GSM for short. As its name implies, this standard
was developed for, and has been adopted by, almost the entire globe as the way
to communicate via cellular calls.
But not everyone has jumped on
the GSM train. An alternative cellular standard known as Code Division Multiple
Access, or CDMA, is used by many carriers around the world. It is most popular
in the United States and Russia, but it’s also used in some Asian and
African countries, often alongside competing GSM carriers.
Here’s what cell phone users stuck
on choosing between them should know before purchasing a phone.
GSM
vs. CDMA: What’s Better?
This is the first question many
potential owners ask, and it makes sense, but in this case there’s no easy
answer to that question.
GSM and CDMA are different ways to
accomplish the same goal, and the fact that extremely popular networks are
built on each simply proves that it’s the quality of the network, not the
standard, which is important. For instance, in the United States, two of the
four major carriers (Verizon and Sprint) use CDMA while the other two (AT&T
and T-Mobile) use GSM.
Technically, neither is
the better in terms of quality, but there are some things here for your
consideration. GSM phones are able to be unlocked and moved between carriers, but CDMA phones are often
locked to a single carrier and unable to be transferred.
Additionally, most phones only
come in GSM or CDMA models, so your choice of phone could
determine which standard you end up using, and it all depends on which carriers
are available to you in your area. Some areas may be better covered by
GSM-providers, while CDMA-providers will have better coverage in other areas.
What
Phones Support Which?
Many phones are compatible
with either GSM or CDMA, but not both. For CDMA phones, you will need
to buy a phone made for your specific carrier, and the easiest way to do this
is buy directly from your carrier. For example, if you want an iPhone on
Verizon, you need to buy a Verizon-branded iPhone — not a Sprint- or
AT&T-branded iPhone — because it has the specific bands and compatibility
with Verizon. However, if you ever want to leave Verizon, you won’t be able to
take your phone with you; it is locked to that carrier.
If you don’t want to be trapped with one carrier, however, you can also look for unlocked GSM phones from
third-party retailers — these phones will work with any GSM carrier simply by popping in your SIM card. For example, Amazon sells tons of unlocked GSM
phones, and Google sells their Nexus 5 and a couple Google Play Edition phones unlocked.
Any retail or online store dealing in cellular phones should provide
information regarding the networks a phone works with.
You must be careful when examining a
phone’s network compatibility, though. Phones sold in markets that service both
standards often come in a GSM version or a CDMA version, but
only a few phones are compatible with both. If you buy a CDMA phone from a
third-party retailer, you’ll need to call your carrier to have it activated. If
you buy a GSM phone, you’ll need to purchase a SIM card to put into your phone
that will activate your phone’s network capabilities.
Owners of CDMA phones don’t need to
worry about SIM cards, but this is more a curse than a blessing. CDMA
phones bake in compatibility restrictions that are difficult to get
around, while GSM owners can simply take out their SIM and replace it with one
from another carrier. Most CDMA networks do not allow the use of a phone
originally purchased from another carrier even if the phone is otherwise
technically compatible. This is an important restriction to remember when going
with a CDMA network. If you decide to switch networks later you’ll likely need to buy a new phone even if
the network you’re switching to also uses CDMA.
While GSM is more open, the
frequency bands supported by a phone can still restrict access. There are
a number of bands from 380 MHz to 1900 MHz and the bands used can
vary from market to market. You should double-check your local carrier’s
band usage and make sure the phone you’re buying supports the same. With
that said, GSM is concentrated around a core of four bands, those being 850,
900, 1800 and 1900. A phone that supports all four can be used in most
countries, which is why GSM phones compatible with all four bands are
often called a “world phone.”
LTE
Cometh, And Carries Confusion
If you now understand the importance
of GSM and CDMA, awesome! Now let’s entirely destroy your assumptions by
talking about the newcomer, Long Term Evolution (LTE).
LTE is a new standard that’s
come into vogue over the last few years. Though based on the principles of GSM,
LTE is its own separate standard that operates apart from existing GSM and
CDMA networks — it’s the real fourth generation of cellular data.
The highest adoption of LTE can
be found in South Korea, where it commands the majority of the market, but
it is also popular in Japan, Australia, Sweden, and the United States. So
far it’s used primarily for data, but standards have been drawn up for using
LTE as a replacement to traditional cellular networks. Verizon Wireless in the
US, for example, has announced its plan to roll out LTE-only phones in late
2014.
This standard uses a SIM card, so
users can switch networks by replacing the SIM if the phone is compatible with
the new network. With that said, at this time phones that use LTE generally use
it only for data, but not for voice. This means CDMA/LTE phone owners are still
locked into a network. That will change as carriers like Verizon move to
LTE-only networks, but this process could take many years.
While it has the potential to be a
global standard, there are some obstacles in the way. Outside of South
Korea there’s no market where LTE’s reach is more than a quarter of the
services available. South Korea in general, and Verizon Wireless in the
US, are exceptions to the rule; in most markets, even carriers that offer LTE
only offer it in a slim selection of the total area they cover.
And then there’s the problem of
spectrum. Remember how GSM/CDMA operates on many different bands? The same
is true of LTE. You need to check that the compatibility of your phone matches
the frequency band supported by your carrier, and you won’t be able to use an
LTE phone on other networks with the same standard, but a different frequency
band. It’s unclear at this point if this standard will ever become “global” in
the same way as GSM, which settled on a core of four frequencies across the
world that are supported by most GSM phones.
Wrapping
It Up
Take a deep breath; it’s time to
review this buffet of confusing information.
First, neither GSM nor CDMA is
technically better; they ultimately provide the same service and the
quality of a network depends on the carrier, not the cellular standard used.
Second, GSM phones can be unlocked
and switch carriers, whereas CDMA phones are locked to a carrier. It’s usually cheaper to buy unlocked GSM phones than on-contract CDMA phones.
Third, you need to check what bands
your chosen phone supports carefully. Most either work on GSM or CDMA,
or both standards offer multiple frequencies that differ across the globe.
Finally, LTE is being rolled out as
a potential global standard, but it falls victim to even
more frequency division than GSM and CDMA. The technology also suffers
from limited adoption because it’s relatively new.
Hopefully this has cleared up any
questions you had, but cellular service is undergoing constant evolution and
the standards commonly supported by phones can change from year to year. Feel
free to leave your questions and comments below.
Guide.
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