Radio Spectrum

The first generation of mobile networks needed frequencies that could cover large areas without requiring an impossibly expensive network of base stations. The 900 MHz band was particularly attractive because its radio signals travelled relatively long distances. But this was not empty spectrum waiting to be used. Existing government, defence and fixed radio services had to be accommodated, while European governments needed to agree on common frequencies if mobile phones were ever to work across national borders.

In Britain, Racal-Vodafone and Cellnet received the first cellular licences in the early 1980s. Both used frequencies around 900 MHz for analogue mobile telephone services, initially serving a market dominated by car phones and business users. GSM subsequently brought digital communications into the same broad frequency range. International agreements, European cooperation and the 1987 GSM directive helped establish common frequencies, laying the foundations for an international mobile phone market.

As mobile demand increased, the available space around 900 MHz became a serious constraint. Stephen Temple proposed opening the 1800 MHz band years earlier than industry experts considered practical. Some of these frequencies were occupied by police and fire-service radio links. Higher frequencies also meant shorter range and more expensive networks. But the advantages were substantial: much more spectrum, room for new competitors and the opportunity to build networks around smaller, truly portable phones.

In 1989, the British Government selected three proposed Personal Communications Network operators: Mercury PCN, Microtel and Unitel. The arrangements subsequently evolved, with Mercury One2One and Orange becoming the best-known 1800 MHz networks. Unlike the later spectrum auctions, these licences were awarded through government selection procedures. The object was to encourage competition and make mobile telephones affordable to a mass market.

The arrival of 3G promised to transform the mobile phone from a device for calls and messages into a gateway to the Internet. Frequencies around 2.1 GHz were identified internationally for the new technology, and existing radio users had to make way. Governments now faced a different question: rather than selecting operators through administrative procedures, why not sell the spectrum to the highest bidders?

Britain's 3G auction in April 2000 produced an extraordinary result. Five licences raised £22.48 billion. Vodafone paid £5.96 billion, TIW (later associated with Three) £4.38 billion, Orange £4.10 billion, BT3G £4.03 billion and One2One £4.00 billion. The Government received a financial windfall, but Stephen Temple's account examines the consequences for operators forced to commit such enormous sums before they had built their networks or established a market for 3G services.

The next generation required another reorganisation of the airwaves. For 4G, the 800 MHz band offered wide coverage and good reception inside buildings. It became available through the reorganisation of television broadcasting following digital switchover. The higher 2.6 GHz band offered additional capacity where demand was greatest. Meanwhile, EE demonstrated that existing spectrum could also be reused, launching 4G in its 1800 MHz frequencies before the new auction was completed.

The UK's 2013 auction raised £2.37 billion—about one-tenth of the 3G proceeds. Five organisations received licences: Vodafone paid approximately £803 million, EE £589 million, Telefónica/O2 £550 million, Three £225 million and BT's Niche Spectrum Ventures £202 million. One of the 800 MHz licences, awarded to O2, also carried a substantial national coverage obligation. The difference between the two auctions raises an important question: did the amount paid for spectrum determine how successfully it was put to use?

The early vision for 5G concentrated heavily on exceptionally fast connections using very high radio frequencies. But the frequencies capable of delivering spectacular speeds over short distances could not provide the widespread coverage a national mobile network needed. They also had existing users whose rights and services could not simply be ignored. Stephen Temple helped break this impasse by developing the concept of three complementary European pioneer bands.

The 700 MHz band, previously used for television broadcasting, offered long-range coverage and better penetration into buildings. The 3.4–3.8 GHz range offered a balance of coverage and capacity, making it particularly valuable for mainstream 5G networks. The 26 GHz band offered enormous additional capacity in crowded locations, although its shorter range and existing fixed-radio users created different challenges. Selecting these three bands gave European countries a common direction for research, equipment development and commercial deployment.

Agreeing on European pioneer bands did not itself grant licences to mobile operators. Each country still had to release the frequencies and decide who could use them. In Britain, the 2018 auction of 2.3 GHz and 3.4 GHz spectrum raised approximately £1.37 billion, with licences awarded to EE, Three, O2 and Vodafone. The 2.3 GHz spectrum supported 4G, while 3.4 GHz provided an important starting point for 5G.

A further UK auction in 2021 released 700 MHz and 3.6–3.8 GHz spectrum to the same four operators, raising £1.379 billion. In 2025, EE, O2 and VodafoneThree each paid £13 million for additional 26 GHz and 40 GHz spectrum, bringing that auction's total to £39 million. These different awards show how 5G moved from a coordinated European spectrum strategy into national licensing decisions—and how the value of spectrum varied dramatically according to its characteristics and intended use.

The spectrum for 6G is still being debated. Unlike previous generations, there is not yet an agreed set of frequencies exclusively licensed for 6G networks, nor a corresponding list of operators and licence prices. What is already clear is that any new frequencies will have to coexist with other services, while existing mobile bands will continue to play an important role.

One area attracting attention is the upper 6 GHz band, from 6425 to 7125 MHz. It offers the prospect of additional mobile capacity, but Wi-Fi and other radio services also have an interest in these frequencies. Ofcom has been examining how mobile networks and Wi-Fi might share access. International studies are considering further frequency ranges ahead of the 2027 World Radiocommunication Conference. These are potential opportunities, not final allocations or licences already sold to operators.

Stephen Temple's 6G Vision asks a more fundamental question: what improvements would justify another generation of mobile infrastructure, and who would pay for them? Drawing on his continuing work in mobile technology and government policy, he examines whether 6G should evolve from existing networks or require a more radical change. The decisions about technology, spectrum, investment and international cooperation are closely connected. Their outcome will determine what 6G actually becomes.