O2 UK, officially known as Telefonica UK Limited, is a telecommunications services provider operating in the United Kingdom. The company was established on 7 January 1985 as Cellnet, a joint venture between BT Group and Securicor. In 1999, BT Group acquired Securicor's share of Cellnet, and the company was rebranded as BT Cellnet. In 2002, BT Group spun off its wireless division to form a new holding company, mmO2 plc, which introduced the "O2" brand. In 2005, mmO2 plc was renamed O2 plc. In 2006, O2 plc was acquired by the Spanish telecommunications company Telefónica for £18 billion.
3G Network
The company began providing 3G UMTS services over B1 (2100 MHz) between February 2005 and September 2007 when the network rollout was deemed completed. A B8 (900 MHz) carrier was introduced in March 2011 to improve network coverage. Data services were upgraded to HSPA+ during 2012 and DC-HSPA+ in 2013.
The 3G network shutdown was announced for end of 2025.
3G Frequency Bands
| Network Frequency Band | Status |
|---|---|
|
Active
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3G Network Events
| Date | Event | Subtype |
|---|---|---|
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|
Launch of 3G Network
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Launch
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4G Network
4G LTE services were first launched in August 2013 over the B20 (800 MHz) band. By early 2016 O2 had refarmed 5 MHz of its 2G spectrum to implement B3 (1800 MHz) and 10 MHz of its 3G 2100 spectrum to provide an additional B1 (2100 MHz) LTE carrier. The new bands were immediately used to implement LTE-Advanced using 2C CA. 4X4 MIMO has been implemented since April 2018.
After securing 40 MHz of 2.3 GHz spectrum in early 2018, O2 launched two 20 MHz B40 (2300 MHz) LTE carriers. There were unconfirmed reports of 8T8R MIMO being implemented.
B8 (900 MHz) services were added in September 2021.
4G Frequency Bands
| Network Frequency Band | Max. Channel Bandwidth | Status |
|---|---|---|
|
10
|
Active
|
|
|
5
|
Active
|
|
|
10
|
Active
|
|
|
10
|
Active
|
|
|
20
|
Active
|
|
|
20
|
Active
|
4G Network Events
| Date | Event | Subtype |
|---|---|---|
|
|
Launch of 4G Network
|
Launch
|
5G Network
At an April 2018 Ofcom auction, O2 secured a total of 80 MHz of 5G-suitable TDD spectrum in the 2.3 and 3.5 GHz ranges (40 MHz each). In February 2019 O2 confirmed it would begin construction of its 5G network infrastructure, beginning in the cities of Belfast, Cardiff, Edinburgh and London, with a switch-on to take place in 2020. O2 announced that it would launch a 5G trial network at its Millbrook Proving Ground in June 2019 using n40 (3400 MHz) and n78 (3500 MHz) carriers.
The company's 5G network commercially launched in October 2019 using n78, later adding a low band n28 (700 MHz) carrier in October 2021. The network was upgraded to Standalone (SA) in February 2024.
5G Frequency Bands
| Network Frequency Band | Max. Channel Bandwidth | Status |
|---|---|---|
|
80
|
Active
|
|
|
10
|
Active
|
5G Network Events
| Date | Event | Subtype |
|---|---|---|
|
|
Launch of 5G Network
|
Launch
|