Ofcom has agreed to let BT and Everything Everywhere extend their 4G trial in St Newlyn East, Cornwall.
The project was due to finish at the end of January, but will now continue until at least the end of June 2012.
Everything Everywhere said the trial had proven fixed and mobile technologies can combine to provide a viable option for taking broadband to rural areas.
There isn't a single silver bullet to meet the rural broadband challenge.
The company said it had also shown how low frequency spectrum, such as the 800MHz spectrum due to go on sale during the twice-delayed Ofcom auction this year, was ideal for providing broadband in remote parts of the UK.
Earlier this month, Ofcom backtracked over guaranteeing Everything Everywhere sub-1GHz spectrum in the auction. The regulator said the operator would be able to effectively bid for 4G and provide LTE connections without Ofcom assistance.
Trialists in St Newlyn East, some of whom had previously received no broadband at all, were able to get an average download speed of 7Mbps.
"This trial has been key in investigating ways to rapidly bring 4G LTE to Britain, and Ofcom is helping us do the groundwork to accelerate the UK from laggard to leader," said Olaf Swantee, CEO of Everything Everywhere.
Nigel Stagg, CEO BT Wholesale, noted how the trial had helped offer a lifeline for rural areas.
"This trial is enabling us to see at first hand the real difference LTE is making in rural Cornwall and how it could provide an alternative mode of delivery in rural areas to complement fibre delivered broadband," Stagg said.
"There's no doubt that fixed line solutions offer a faster and more reliable broadband service, but there isn't a single silver bullet to meet the rural broadband challenge."
The announcement came just days after it emerged Virgin was testing out 4G connectivity in central London, but not with consumers.
Neither Virgin or BT have confirmed whether they will bid in the Ofcom auction, set to take place at the end of 2012.
