GSM is an abbreviation of Global System for Mobile communication, originally it is known as Group Special Mobile.
It is mobile telephony system that sets the standards on how mobile telecommunications work.
It encompasses everything in reference to mobile communications.
However, in this context of comparing GSM and UMTS, we will refer to GSM as a service or technology.
GSM is a second generation (2G) telecommunications technology which is launched early in the 90s.
Eventually, it increased its speed and added more functionality like General Packet Radio System (GPRS) to the system which enhanced it to 2.5G status.
2.5G has data rates up to about 144kbit/s. It typically uses a variation of Time Division Multiple Access (TDMA).
Today, in a global scale, GSM is still widely used mobile service.
There are about 700 mobile networks that provide GSM services across more than 200 countries.
Statistically, more than 80 percent of all global mobile connections are GSM.
With GSM, subscribers can still continue using their mobile phones when
traveling to other countries because GSM network operators have expansive roaming agreements with foreign operators.
UMTS is the third generation (3G) of mobile telecommunications technology.
It is the latest commercially available technology that mobile phones, PDAs, and smart phones are using today.
With this development, internet access (email and web browsing), video calling and messaging,
and text messaging (SMS) are now possible along with traditional phone tasks.
People can now do the activities they normally do with an internet-connected home computer while on the trot.
Imagine yourself traveling the world and still able to email, video conference, and watch streaming videos using your smartphone.
Currently, it can offer transfer speeds of about 3.6 Mbits per second and even more,
which can make data transfer seamless and downloads relatively fast.
Unlike GSM, UMTS is mainly based on CDMA (Code Division Multiple Access) scheme and now combines it with TDMA.
However, UMTS is still new as there are only a few areas and networks that support the technology.
Even with countries that support it may have set different spectrum,
thus interoperability does not work fully when moving from one nation to another nation with drastically different spectrum.
There are also problems regarding the compatibility between UMTS and GSM,
which frequently led to connections being dropped. But this is being remedied by UMTS/GSM dual-mode devices.
With that feature, UMTS phones that go out of UMTS network boundaries will be transferred to GSM coverage.
Transfer of network can happen mid-call. Summary:
1. UMTS has faster data transfer rates than GSM.
2. GSM is 2G and 2.5G while UMTS is already 3G.
3. GSM is a rather old technology while UMTS is newer.
4. GSM is typically based on TDMA while UMTS is mainly CDMA-based.
5. Currently, GSM is still the most widely used technology today while UMTS is still in its infancy, slowly creeping forward.
