HSDPA Frequencies Confuse Roaming Picture

It seemed as if the confusion over traveling internationally, or purchasing a GSM phone, had been sorted out: Get a quad-band GSM phone and you'll be set most anywhere in the world that has cellular coverage.

Enter HSDPA (for High speed data packet access). HSDPA otherwise referred to as UMTS, is the high-speed data access technology, often called 3G, most widely used by GSM carriers.

Problem is HSDPA works on different frequencies. So, you can buy a tri- and quad-band GMS phone, only to find it's high-speed data for browsing works only in one region. Now, you'd actually need a phone with ten bands (deca-band?) to cover voice and data everywhere.

Here are the HSDPA/UMS frequencies:

1. Europe and Asia: 2100 for the downlink and 1900 for the uplink.
2. American on AT&T: 1900 and 850, independently for both uplink and downlink.
3. American on T-Mobile: 2100 downlink and 1700 uplink. (Reported, but no national plans announced yet. Rumored for December.)

A number of leading-edge phones from Nokia and Sony-Ericsson are being sold in the U.S. that advertise 3G/HSDPA ability when they, in fact, only work on the Euopean/Asian 2100/1900 links.