Vodafone has said this morning that the first of a trial group of Auckland customers have gone live on its HSPA+ network, and can expect mobile data download speeds of up to 16Mbit/s - that is, the same speed as most get from a landline DSL broadband connection, if they're lucky.

47 Auckland cellsites have been upgraded to the technology, all with fibre backhaul courtesy of the telco's partnership with Vector.

The trial will expand to include 100 Auckland customers.

The carrier says it will roll-out HSPA+ nationally during 2010, but has yet to commit to a more specific time timetable. It says urban areas will be upgraded first during the first few months of the New Year.

Telecom has pledged to upgrade its entire 3G network to support HSPA+ by Christmas.

A turbocharged version of the HSPA technology that underpins both Vodafone and Telecom's 3G networks today, HSPA+ triples the maximum theoretical data download speed to 21Mbit/s.

Neither Telecom nor Vodafone has so far elaborated on how it will adjust its mobile data pricing to accommodate such superfast mobile broadband. If plans are left unchanged, it would be easy for a customer to blow through their monthly data allowance within an hour.

To take advantage of HSPA+ pumping at 21Mbit/s, you must have a cellphone or data card that support the technology. There are several data cards available that support HSPA+ at 21Mbit/s, but no cellphones at present. Vodafone said today that it will add HSPA+ data sticks and cellphones to its range.

At this point, a specific Vodafone HSPA+ sim card is also required, restricting access to the 100 official trialists.

Today's 3G networks have a maximum theoretical top speed of 7Mbit/s, although NBR testing, and that carries out by others, typically finds both clocking less than half that bandwidth.

Telstra rolled out HSPA+ in selected Australian urban areas earlier this year, with 21Mbit/s support in some areas, and 43Mbit/s in others.