The UK will have access to super-fast 4G services by the end of next year.
The auction will offer the equivalent of three-quarters of the mobile spectrum currently in use - some 80 per cent more than released in the 3G auction which took place in 2000.
It will give access to the fourth generation, or 4G, network, to at least 98 per cent of people across the UK, which will allow users to download data - such as music and high-definition films - at much faster speeds, Ofcom said.
The minimum sum of proposed reserve prices for the whole 4G auction is £1.4 billion - but it is expected to raise much more after the 3G sale pulled in a staggering £22.5 billion from mobile companies.
Ofcom said it expects the auction process to start before the end of this year, with prospective bidders required formally to apply to take part. Those applications will then be assessed by Ofcom before the bidding phase starts, likely to be in early 2013.
Mobile operators are expected to start rolling out 4G networks using the auctioned spectrum from the middle of 2013, and to start offering 4G services to consumers later that year, Ofcom added.
Ofcom chief executive Ed Richards said: "The 4G auction has been designed to deliver the maximum possible benefit to consumers and citizens across the UK.
"As a direct result of the measures Ofcom is introducing, consumers will be able to surf the web, stream videos and download email attachments on their mobile device from almost every home in the UK."
Ofcom decided to reserve a minimum amount of spectrum in the auction for a fourth operator on top of the three biggest mobile companies - Vodafone, 02 owner Telefonica, and Orange and T-Mobile firm Everything Everywhere.
The new auction will offer at least two spectrum bands - 800 MHz and 2.6 GHz.
The lower frequency 800 MHz band is ideal for widespread mobile coverage, while the higher frequency is ideal for delivering the capacity needed to deliver faster speeds.
The combination of low and high frequency spectrum creates the potential for 4G mobile broadband services to be widely available across the UK, while offering capacity to cope with significant demand in urban areas.