The cost of such a mobile is also likely to be high and with possibly low battery life. As such, such a mobile is quite complex and rarely implemented. There is no coordination between the two service domains. RF duplexers may be needed along with multiple call processing units. This class of a mobile may even require two transceivers because CS and PS could be on different frequencies. A CS call in the middle of PS call will not disrupt the latter.

Class A: supports simultaneous attach, simultaneous activation, simultaneous monitor, simultaneous invocation and simultaneous traffic.

GPRS standards provides for three classes of MS: How then can we meet user expectations when an inter-RAT handover from UMTS to GPRS will necessarily mean dropping the packet connection? Whatever be the case, one of the keys problems for GPRS is that CS and PS traffic cannot happen simultaneously.

It will take time for users to give up their old handsets in favour of 3G-enabled handsets.

It will take time for users to switch consumption patterns, to move from voice-centric to data-centric.

Because WCDMA at 2100 MHz generally lacks the indoor coverage that’s possible with GSM 900 MHz, this leads to another use case for inter-RAT handover.Operators have invested considerably in 2.5G and the move to 3G will at best be a transition.3G may be deployed at the level of microcells while at the macrocell level 2.5G may be used.This means that movement from urban to rural will trigger an inter-RAT handover. Going by demand, deployment of 3G cells will happen in phases whereby urban areas could be covered by 3G while rural areas continue on 2.5G.It was correctly envisaged that this coexistence will happen for the following reasons: More than competition, it was completion and cooperation.

Rather, these two access standards will co-exist for a long time to come before 3G completely replaces 2.5G. The greater truth is that everyone knew that UMTS will not replace GSM/GPRS overnight. So when GPRS saw the upcoming competition from UMTS it had to invent new methods to keep itself alive longer in the cellular world. They say necessity is the mother of invention.

Multislot class power class