hi mkt,
CDMA2000 works on 1.25 MHz, while WCDMA works on 5MHz. Both technologies are incompatible. So if your network is in CDMA2000, it won’t accept WCDMA..
CDMA2000 : US patented, easy evolution from 2G to 3G
WCDMA: no patents, open technology, difficult evolution from 2G (from GSM…). Regarded as worldwide standard.