Vodafone has said that it has successfully trialled a new version of mobile broadband technology that achieved peak download speeds of up to 16Mbits/s.

Vodafone said last Thursday that the high speed data connection was achieved during field trials on its Spanish network using HSPA+ 64QAM technology (64QAM is the name of a more advanced modulation technique).

"We are only trialling download speeds at the moment, so we don't have any figures on upload speeds," a Vodafone spokesman told Techworld.

The mobile operator did say however that it is now planning to trial mobile broadband with peak rates of up to 21Mbit/s early in 2009, using HSPA+ MIMO (Multiple Input Multiple Output) functionality.

But it was keen to add a touch of reality to the headline grabbing figures, with its experts estimating that while the technology would be capable of delivering a video download of more than 13Mbits/s in good conditions, an average of more than 4Mbits/s across a full range of typical cell locations (including urban environments) would be more typical.

"We have to be tried to be transparent about this," said the Vodafone spokesman. "We have said that you could expect speeds of 16Mbits/s. But we would deliver an average of 4Mbits/s, and in good conditions up to 13Mbits/s." According to Vodafone, good conditions means there being not too many people on the network, suitable atmospheric conditions, and the devices used.

"We are trying to be realistic and not talk about peak speeds," Vodafone said. "Our initial indications are showing that these figures are achievable."

Customers making use of Vodafone's existing HSPA network can surf at speeds of up to 7.2Mbits/s, but in reality they can expect to see an average range anywhere between 1Mbits/s to 5Mbits/s, depending on how close to a hotspot and base station the user is.

Vodafone is not revealing how much it will cost to roll out HSPA+ in the UK. "The big advantage of this is that it follows the HSPA roadmap, so it does not call for large capital outlays," said the spokesman.

Indeed, at the moment, HSPA+ would mean a software-only upgrade for base stations. "However, the next stage of the trial will include MIMO functionality, and that will need extra hardware (multiple antennae on both base stations and data devices) to be installed.

As it is, Vodafone confirmed that users would need a new dongle when HSPA+ is rolled out. And it seems there will be no blanket rollout, with the technology following previous rollouts, being firstly implemented in hotspots, followed by airports and large city centres etc.

Last week, Graham Currier, Chief Operating Officer at Freedom4 warned that the popularity of mobile broadband was misleading. "Where is the capacity of mobile broadband coming from? It simply isn't there," he said. "The minute you get contention, you don't get any data, you get squeezed by voice."

"We can only say we have a lot of satisfied customers," Vodafone responded. "Our networks are capable of coping with the numbers. We focus resources on where they are most needed. We are giving people what they want."

That said, there is little doubt about the chances of data being dropped (however briefly) in preference of voice, when the network is overloaded.

"Voice is real-time application; if you are using a data connection, data has certain amount of latency built into it, with more scope for a drop of information," said Vodafone. "Data is more tolerant so obviously there is no latency on voice. It is all about the most efficient way to use the resources currently available."

And on LTE, Vodafone said it still remains committed to the 4G technology, after TeliaSonera recently announced the planned construction of a commercial LTE mobile broadband network in Stockholm, Sweden and in Oslo, Norway.

"LTE still needs more development," said Vodafone. "We are not letting up on it and we are committed to making it commercially viable. But this (HSPA+) is more immediate and readily available. The two don't contradict each other, and we remain one of the driving forces behind LTE."