Mobile Phone Technology

In the UK, Ofcom is responsible for allocating and overseeing the frequencies used for communication. This includes TV, mobile and other radio communications. Initially, they allocate frequencies specifically for a 'generation' of mobile communications. Later, companies are given permission to use frequencies for different purposes due to various factors, including the relative demand for the frequencies. Therefore, what starts off as a very organised allocation can change over time. Ofcom also reallocates frequencies to treat companies fairly in the event of takeovers and mergers.

Initially, 2G was transmitted on the 900 MHz frequency, which was allocated to Vodafone and O2. The 1800 MHz frequency was allocated to Orange and T-Mobile; T-Mobile has since been taken over by EE. Following the merger of Orange and T-Mobile, some reallocation of the 1800 MHz frequency to Vodafone and O2 was arranged. These are currently the frequencies used for 2G. EE was permitted by Ofcom to use its spare capacity on the 1800 MHz band for its initial 4G operations.

3G was originally transmitted at 2.1 GHz, with the frequency band shared between five operators: Vodafone, Three, O2 and EE (formerly Orange and T-Mobile). Now that 3G has almost been switched off, this frequency will be refarmed to support the 4G network, once Ofcom permits it.

The original 4G frequencies were 800 MHz, which provided coverage across the UK, and 2.6 GHz, which was used to increase capacity. All operators have access to the 800 MHz frequency, but only Vodafone and EE have access to the higher frequency. Three preferred to refarm their 1800 MHz allocation for 4G use. O2 operates its entire 4G network at 800 MHz.

The same split between coverage and capacity was repeated with 5G. The 700 MHz band was used to provide coverage, while the 3.4–3.8 GHz band was used to provide capacity. Vodafone decided not to buy any 700 MHz frequencies as they already had plenty of 800 MHz/900 MHz frequencies that could be repurposed. The auction for the higher frequencies was more complex, as Three owned many of the 3.6–3.8 GHz frequencies following their purchase of UK Broadband, and there was a requirement for each operator to have a continuous block of frequencies in this range, rather than split blocks.

Ofcom is currently considering releasing 26 GHz for mobile phone operation. These millimetre waves are different in nature to all other frequencies and are not suitable for 'normal' mobile phone operation. They do not travel far, but they have great capacity and are likely to be used for industrial applications.

	2G	4G	5g
Three	-	800Mhz 1800MHz 2100MHz	700MHz 3.4-3.8GHz
O2	900MHz 1800MHz	800Mhz 180MHz 2100MHz 2300MHz	700MHz 3.4-3.5GHz
Vodafone	900MHz 1800MHz	800Mhz 1800MHz 2100MHz 2600MHz.	3.4-3.8GHz
EE	1800MHz	800Mhz 1800MHz 2100MHz2600GHz.	700MHz 3.4-3.8GHz

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