Don't expect a UK LTE network before 2011

And just how much would a next-gen mobile network cost?

LTE (Long Term Evolution) has been widely regarded as the heir apparent to today's cellular network standards for some time. But don't hold your breath: any rollout of a next generation mobile network in the UK is still years away, says telecoms kit maker Ericsson's UK CTO John Cunliffe.

"I would say probably the end of 2010 at the very earliest," he told silicon.com. "Networks will be ready for rolling out - shipping in commercial quantities - next year and then the devices, we think, will start to come in 2010," he added.

According to analysts ABI Research, multimode WiMax/LTE chipsets will be available from 2009 and, by 2013 the researchers believe 32 million consumers will be signed up to the networks.

There remain, however, many unknowns in LTE's roadmap, not least how much it will cost to build a network - something likely to give operators pause for thought, especially in the current economic climate.

Cunliffe would not give an estimate on how much a commercial rollout of LTE in the UK might cost. "People need to do more modelling around rollout costs," he said. "It's a new equation."

However, he claimed operators switching to LTE would reap the benefits of "total lower capex and lower opex" - provided they are willing to stump up the infrastructure cash.

However Cunliffe highlighted that any large-scale deployment of rival 4G technology WiMax would also require similar investment in infrastructure to that of an LTE deployment. "If you think about WiMax starting off as essentially a radio you need a much bigger ecosystem around it," he said.

"By the time you actually deliver a service, the operators still have to pay for the infrastructure that goes around it and they've still got their opex - their people costs and so on - so the WiMax piece - the radio piece - is actually a small piece of the equation. In terms of the maturity of the 3GPP ecosystem, it's well ahead of where WiMax is."

Another aspect to consider when it comes to mobile's 4G future is how much existing 3.5G services can be milked, as the potential speeds for HSPA is pretty impressive. Cunliffe noted: "We often forget that HSPA [high speed packet access or 3.5G] has a roadmap which will take it higher than the current speeds.

"The fastest being deployed in the UK at the moment is 7.2Mbps but our roadmap continues until 42Mbps. We can even see that it may be possible for the technology to reach as much as 80Mbps…so there is certainly a lot of mileage in HSPA…People maybe think that we've got to have LTE to get to the higher speeds but HSPA will go a long way before we need to get to LTE speeds."

Cunliffe added the top speed of LTE currently being demoed by Ericsson in lab conditions is 160Mbps and a drive test has reached a maximum of 154Mbps, with an average of 78Mbps.

Once an LTE network is up and running, the Ericsson CTO said increasing demand for on-demand video services could mean some local media content caching could be required to keep up with users' thirst for YouTube and BBC iPlayer.

"[On-demand video] does put a lot of pressure on the backhaul and the core networks - and will increasingly put pressure on them - but there are solutions which scale, which will accommodate it."

What are the biggest hurdles to a UK LTE network being rolled out? Cunliffe believes they are timing - when operators will switch, especially those with significant investment in HSPA - as well as the inexorable issue of ROI: "Obviously there will be questions about return on investment," he concluded.