Scheduled for 2021, four players will bid for allocations in the 700 MHz and 3.6-3.8 GHz bands. They are: EE Limited, Hutchison 3G UK Limited, Telefónica UK and Vodafone.
It would increase the amount of spectrum available to operators by 18% and the additional range is likely to be used by MNOs to deliver a range of services, including 5G mobile.
Qualified applicants have until 23 December to withdraw from the process if they wish, after which Ofcom said it would confirm the final list of bidders taking part in the auction in January 2021.
In August Ofcom said that Covid-19 restrictions would not prevent the auction taking place with bidders still required to attend the regulator's London HQ (pictured) in person.
The final regulations around the January auction came into force on 18 November 2020.
In 2018 UK mobile operators splashed out more than £1.4 billion on 5G spectrum surpassing revenue expectations.
In that round, Telefonica's subsidiary O2 was the biggest spender, splashing out £317.7 million for 40MHz of 3.4GHz spectrum and £205 million to scoop up all 40MHz of available 2.3GHz spectrum, taking its total spend to £523.6 million.
Vodafone UK was the biggest single spender on 5G spectrum, bagging 50MHz of 3.4GHz spectrum at a cost of £378 million, while BT-owned EE spent £302 million on 40MHz of 3.4GHz of spectrum.
CK Hutchison’s Three UK bid £151 million for 20MHz 3.4GHz spectrum although it already has some 3.4GHz spectrum following its acquisition of UK broadband provider Relish the previous year.
