UMTS AND 3G

UMTS is well known as the technology of 3G; many people say it is the 3GSM. Basically, the UMTS technology is one of the advanced mobile communication technologies for wideband or broadband operations on the GSM infrastructure and its evolved versions. In its modern 3G version UMTS uses WCDMA as the air interface multiple access method.

UMTS system was mainly using the GSM framework for two reasons: first, to retain the existing customers in the same network, and second, to provide new dimensions which are able to give broadband services in personal communication systems.

At present all the major 3G Networks are using the FDD (frequency division duplex) mode of operation. As far as time division duplex is concerned, there are no commercial TDD networks at the moment, although some of the network service providers like T-Mobile have announced that they would install TDD Network in Europe and North America. The reason why TDD has not been used yet is the difficulty in its implementation; when both of them (TDD and FDD) stay together, the situation becomes even more complex.

4G became necessary when it was found that the 3G was lagging behind the competing technologies like the WiMAX. The 4G project and its road map was not very much related to the WiMAX development, but it was later found to be a basic need for the 3GPP members to come out with a better technology. Though there is not much difference between them, it is quite obvious that the 3GPP members do not want to lag behind.

The migration of the 2G to 3G was so smooth in the European countries that many people did not even realize that a transition had taken place. Just using the 3G handsets they were able to get the advanced services from their same service provider. Of course, UMTS subscribers differentiated from GSM subscribers based on a SIM card. For UMTS and GSM subscriber the SIM is different; UMTS subscribers use USIM while GSM subscribers use SIM. However, if the service provider wants, it can provide the 3G services on the same existing GSM SIM. Similarly, in case of the 4G it is expected that the UMTS's advanced version may make it quite flexible for the change from 3G to 4G