Mobile network operators have been given the go-ahead to increase power levels, providing they have support mechanisms in place to help Freeview viewers who suffer interference as a result of the boost.
Ofcom today approved plans to allow operators to up the power used for mobile services in the 800 MHz band. The 800 MHz was previously used for TV services, but restrictions remained in place to avoid interfering with remaining TV services on adjacent frequencies. However, since the restrictions were put in place, TV services have moved further away from the 800 MHz band.
As a result of the changes, some users may be able to benefit from improved 4G/LTE coverage in fringe areas. However, operators will need to show Ofcom they have a mitigation scheme in place to protect Freeview (digital terrestrial) TV viewers should interference arise.
Support scheme
It’s expected that support to affected viewers will be continue to be delivered through DMSL on behalf of network operators. The company was originally set up to resolve 4G interference in 2013. DMSL currently trades under the name ‘restore TV’. It was previously known as ‘at800’. All four mobile network operators (EE, O2, Vodafone and 3) fund the service.
Following the change, maximum power levels are aligned with permitted levels on neighbouring frequency bands. Specifically, Ofcom is now allowing mobile network operators to increase the permitted base station transmit power from 61 dBm/(5 MHz) EIRP to 64 dBm/(5 MHz) EIRP. As part of this change femtocells must implement power controls to minimise interference to adjacent channels. Not all antenna will have their power levels increased. In many areas, power is deliberately held below the maximum allowed, to avoid interference.
- The 800 MHz UHF band was cleared of TV services by mid-2013. The frequency band is also known as “B20”. It is separate from the 700 MHz band, that was cleared of most TV services between 2017-2020. This band is also known as “B28”.