In a response to Ofcom's consultation on permitting so-called "White Space Devices" to share the TV frequency band, Digital UK - who are owned by the BBC, ITV, Channel 4 and Arqiva, stated that it had concerns over the proposed implementation saying that it "could ultimately disrupt TV viewing to noticeable levels."
White Space Devices
When viewers retune their TVs, they will notice the TV scanning past parts of the frequency band where either no TV service is broadcast, or the TV signal being received is too weak to be processed.
White Space Devices are devices intended to use those spare frequencies not used by terrestrial TV services for improved internet connectivity. The development of White Space technology is strongly supported by satellite TV operator Sky, who earlier this year accused Ofcom of being "overly protectionist of DTT [Digital Terrestrial Television] , and unduly hindering the development of alternate, data-based uses in the 600 MHz band", such as White Space Device usage.
To ensure that White Space Devices don't interfere with terrestrial TV signals, Ofcom is proposing to set up a database indicating which frequencies can and can't be used in each individual location, and what power levels they can operate at. There are now concerns about the way Ofcom has compiled its technical data and that the database will in fact allow White Space Devices to use frequencies where an otherwise usable digital TV signal would have been available to householders.
In the consultation, Ofcom claimed that perhaps only a "small proportion" of the 10% Freeview households that might be affected would "suffer harmful interference".
|Digital UK said that the BBC has spotted two errors in documents
issued by Ofcom, raising doubts over Ofcom's assumptions that only few
Freeview viewers would be affected by interference. And with regards
Ofcom's assumptions on protecting Freeview reception, it stated "we are
concerned that the tests included an element of subjectivity which
introduces unquantifiable human factors which reduce the reliability and
repeatability of the results."
It is concerned that there would be no adequate protection against interference from White Space Devices in places such as Bridlington and locations along the south and east coasts where viewers need an advanced aerial installation to receive Freeview and where Ofcom themselves previously agreed not to provide a local relay to improve reception as part of digital switchover.
Digital UK also raises concerns that Ofcom has not correctly taken into account the different configurations of the various multiplexes that make up the Freeview service, and how this causes a variation in susceptibility to interference: for consumers this could involve losing access to one or two groups of channels on Freeview where a "licence-exempt" White Space Device is deployed.
There are concerns that Ofcom plans will not suitably protect these Freeview services from interference from White Space Devices:
It pointed out that there was no evidence that new local TV services and the newly launched extra HD multiplex, currently being rolled out across the UK, carrying channels such as BBC Four HD and Al Jazeera English HD, were going to be "suitably protected" from White Space Device interference.
It further highlighted that "region correcting relays" (transmitters that provide the correct regional news in areas where otherwise the only signal would be from a different TV region, such as those in Derby and North Norfolk) would not be protected from interference under the plans.
Viewers who live in an area where signals from more than one transmitter are available would also not be protected from interference, if they chose to receive Freeview from what was not deemed to be their "main transmitter", for example because the "main transmitter" serving their area provided the wrong regional news or because of local obstructions such as buildings or trees forcing the use of a different transmitter.
Digital UK also noted how reception using indoor and loft aerials could be wiped out from White Space Devices, despite Ofcom insisting that users of indoor aerials be taken into account in previous frequency planning exercises.
It is not the first planned reuse of TV frequencies. Freeview channels were moved earlier this year in parts of the UK to make way for 4G mobile broadband. Digital UK warned against comparisons with 4G, stating that 4G services in the frequency band liable to cause the most interference hadn't yet started, highlighting that White Space Devices would - unlike 4G services - be "licence exempt" and uncontrolled.
Ofcom is considering selling off more TV frequency spectrum later this decade for 5G services, and has even highlighted the fact that terrestrial TV in its current form could be abolished after 2030. Vodafone and Sky are among the most vocal lobbyists in favour of reusing terrestrial TV frequencies for other uses.