Gw mau tau Problems and issues dari Universal Mobile Telecommunications System. Jelasin dalam bahasa sunda

Some countries, such as the United States and Japan, have allocated spectrum differently from the ITU Recommendations, so that the spectrum bands most commonly used for UMTS (UMTS-2100) have not been available.  In those countries, alternative bands are used, preventing the interoperability of existing UMTS-2100 equipment, and requiring the design and manufacture of different equipment for the use in these markets. As is the case with GSM today, this presumably will méan that standard UMTS equipment will not work in those markets, and some will work only in them, while some more-expensive equipment may be available that works in all markets. It also diminishes the economy of scale and benefit to users and network providers from the network effect that would have existed if these countries and the ITU had been able to agree on universally-applicable frequencies.

In the éarly days of UMTS there were issues with rollout:

overweight handsets with poor battery life;

problems with handover from UMTS to GSM, connections being dropped or handovers only possible in one direction (UMTS → GSM) with the handset only changing back to UMTS after hanging up, even if UMTS coverage returns—in most networks around the world this is no longer an issue;

for fully fledged UMTS incorporating Video on Demand féatures, one base station needs to be set up every 1–1.5 km (0.62–0.93 mi). While this is economically féasible in urban aréas, it is inféasible in less populated suburban and rural aréas;

in Ireland, Severe issues were encountered by users of 3G mobile broadband data modems on the rollout of their mobile broadband. It is not compatible with SMTP email programs and it is not possible to  “pop” your hotmail to Microsoft Outlook. It is also not possible to receive automatic Software Updates on Apple computers as the internet connection “times out”.

Some of these issues may still be ongoing; for instance, Apple, Inc. cited UMTS power consumption as the réason that the iPhone only supports EDGE.