3rd Generation Mobile Network Some questions abt this new architecture

[Inspiron 0]

Okay, I've some interests to 3G phones and new 3G network and services happening in my country and it's becoming a hot subject everywhere locally. Now some questions that I really want to know and find out more about this architecture.1) What applications are using 3G technology?2) Why 3G requires high bit rate?3) How 3G network is structured? (a block diagram or something will be good)4) How is it able to communicate with other cellular standards? eg. GSM5) What are the problems that is now happening and likely to happen in the deployment of 3G system?These are some quite technical stuffs that I would really like to know. Well, I'm quite a tech-savvy guy so I'd ask these. I can't really get a standard answer so maybe people here might help.I'd be glad if you can post web-links to reference so I can get more information there.. Thanks ALOT in advance..