Freeview could get up to ten more high-definition channels under a proposal put forward by Ofcom to reuse existing radio spectrum.
The regulator said that the 600 Mhz band freed up by the analogue TV switchover could be temporarily used to enable two new digital terrestrial television (DTT) multiplexes.
According to Ofcom, this would allow the 600 MHz band to "be used to provide around ten HD channels" on Freeview HD.
The proposal is part of Ofcom's preparations for the potential move of DTT services from the 700 MHz to the 600 MHz band in the future. This would enable the 700 MHz band to be used for mobile broadband.
Ofcom said that this shift could go ahead by the end of 2018, but there is a short window from now until then in which the 600 MHz spectrum could be used for another purpose.
Ofcom feels the "most appropriate" use of the band would be for establishing temporary UK-wide DTT multiplexes, potentially opening up more efficient operation of the DVB-T2 technology used for Freeview HD.
"For example, the 600 MHz band could be used to provide around ten HD channels using DVB-T2 and MPEG4 if two multiplexes were deployed," Ofcom said.
The watchdog feels that such a move could help drive consumer take-up of Freeview HD receiver equipment.
Currently there are only four HD networks on Freeview - BBC One HD, BBC HD, ITV HD and Channel 4 HD (S4C HD in Wales has been taken over by Channel 4 HD).
There is scope for another HD channel to launch, but Channel 5 has ruled out introducing Channel 5 HD, so the BBC is currently deciding where the spectrum should go.
Bandwidth on DTT is a rare and valuable commodity, so if Ofcom was able to increase the allocation of HD channels on Freeview, even just temporarily, that could boost the subscription-free platform.
Ofcom says that any spectrum licences granted would most likely run until December 31, 2018, and it would be made clear up front to licence holders "that the spectrum may need to be vacated at that time".
As there is only a temporary window for the spectrum, licensees would be required to launch their service within 12 months of it bring granted. They would also have to reach 50% UK coverage within two years, including 25% coverage each in England, Scotland, Wales and Northern Ireland.
The 600 MHz spectrum covers the range 550 to 606 MHz, comprising seven 8 MHz channels. It was cleared of analogue TV on a region-by-region basis during the UK's digital TV switchover, which completed last year.
The other band formerly used for analogue TV, called the 800 MHz band, is currently being auctioned for new 4G mobile services.
Ofcom has said that the new temporary HD DTT multiplexes would operate in the 600 MHz band alongside next-generation wireless microphones and so-called white space devices, which can wirelessly transfer data.
