The move would benefit carriers O2, Three and Vodafone.
Ofcom has granted permission for using the existing 2G and 3G spectrum for 4G networks, and has enabled carriers to select the type of service they want run on particular bands.
The move would eliminate regulatory obstacles and allow 4G mobile broadband services to be launched on the 900 MHz, 1800 MHz and 2100 MHz bands, while enabling the deployment within shortest time span.
The UK telecoms regulator’s decision would benefit carriers O2, Three and Vodafone, who are competing with EE, the only network in the UK offering 4G.
Ofcom said in a statement: "The benefits to consumers of permitting 4G deployment were likely to outweigh any potential detriment that might, in principle, arise from distortions to competition."
EE was approved to use 2G and 3G spectrum for 4G services in October 2012, and it boosted speeds and brought down prices over the last few months in a bid to capture the 4G market before the rivals’ entry.
Further, the carriers are also not required to undergo a formal application process to deploy the existing resources for 4G.
The spectrum, which would boost the amount of airwaves accessible to mobile phones by more than 75%, was auctioned in February 2013.
It was won by Vodafone, Telefonica UK, EE, Hutchison 3G UK and Niche Spectrum Ventures.