The ACMA has been planning for wireless broadband services in the 3.4–4.0 GHz band since 2019 and is now commencing allocation of licences in the band. We have worked with industry to establish relevant technical conditions to support a range of services in the band, including incumbent services.
The ACMA seeks to maximise the long-term public interest derived from using the radiofrequency spectrum through its efficient planning, allocation and use. This often requires balancing the needs and requirements of a range of different spectrum users.
In Australia, 4G and 5G wireless broadband (WBB) services have been operating in the 3.4 GHz and 3.6 GHz bands since 2016 and 2019, respectively, whereas aircraft radio altimeters operate above 4.2 GHz. There have been no recorded incidents in Australia of WBB systems interfering with radio altimeters.
There has been discussion in the United States and globally about the interaction between 5G and aviation services.
We have worked closely with the aviation and telecommunications sectors, and overseas regulators, to ensure that WBB services, including 5G, and aircraft radio altimeters can successfully co-exist in nearby frequency bands.
We have consulted on how new wireless services in the 3.4–4.0 GHz range could be introduced, including approaches for managing potential interference issues with radio altimeters. The planned arrangements already included a frequency separation of 200 MHz between WBB (such as 5G) and radio altimeter services.
The deployment of 5G and other innovative WBB services in the 3.4–4.0 GHz band (mid-band) is an important government priority that will bring benefits to Australian consumers and industry. Similarly, the government is committed to ensuring the safety of commercial air operations within Australia is not compromised, noting the importance of the reliable operation of radio altimeters to aviation safety.
Interim mitigations
To ensure that an appropriate balance is struck between these 2 important public interests, the ACMA and Civil Aviation Safety Authority (CASA) have worked closely together to identify an acceptable precautionary approach to the deployment of 5G WBB services in the mid-band.
The ACMA is, therefore, putting place interim mitigations on new WBB deployments above 3.7 GHz until 31 March 2026, to manage the risk of 5G interference with aircraft radio altimeters. This will allow the timely roll out of 5G services while providing time for the aviation sector to improve radio altimeter performance.
The interim mitigations will impose restrictions on WBB deployments surrounding runways and approaches identified by CASA. After the end of the interim mitigation period, WBB will be able to rollout consistent with ongoing arrangements that do not include these restrictions. It is anticipated that the interim measures will minimise disruption to aviation operations while giving air operators sufficient time to install any necessary equipment upgrades.
Information on the decision-making and the detail of the mitigations is available in the wireless broadband and radio altimeter coexistence outcomes paper below.
5G and radio altimeters: key facts
About 5G
5G is the fifth generation of mobile network technology. It brings faster network speeds, lower latency, larger capacities and allows for more connected devices. It can potentially support self-driving cars, automated technologies and the internet of things.
5G operates at different bands:
- low-band 5G operates on frequency bands below 1 GHz. These networks support longer ranges and penetration into buildings, with the trade-off of slower speeds and capacity
- mid-band 5G operates on frequency bands between 1 and 6 GHz. These networks provide a balance between range, penetration into buildings and network speed
- mmWave band (or high-band) 5G operates on 26 GHz and above frequency bands. These networks support faster speeds and capacity at the cost of shorter range and less penetration.
5G in Australia
5G services have been operating in Australia since late 2018, with the first commercial launches at the start of 2019. The first band in Australia for 5G was 3.575–3.7 GHz, in the mid-band. Before the launch of 5G, 4G services were using this band since 2016.
In mid-2021, mmWave band 5G started to roll out in some cities, and in late 2021, spectrum licences were auctioned to support the deployment of low-band 5G.
We have now commenced the allocation of spectrum suitable for 5G in the wider 3.4–4.0 GHz frequency range.
About radio altimeters
Radio altimeters are instruments on aircraft used to determine their height above terrain. As a type of radar, they reflect radio waves from the ground to determine the height of the aircraft and are also important for some automated landing procedures.
Radio altimeters operate in the 4.2–4.4 GHz band globally.
Current status
5G is being rolled out in the mid-band around the world.
We are developing arrangements to support 5G services up to 4.0 GHz. The planning objectives are to enable a wide range of WBB use-cases, while protecting various incumbent services. Part of the planning work we undertake is to manage interference between many different spectrum uses. We have undertaken studies and have worked with industry to address any potential coexistence issues between radio altimeters in 4.2–4.4 GHz and 5G services nearby in the mid-band.
Every country has different environments, operating conditions, base station requirements and frequencies, which makes it difficult to directly compare measures between them.
In the United States, 5G has started in parts of the 3.7–3.98 GHz band. The US spectrum management agencies, telecommunications sector and aviation sector have developed mitigations to ensure coexistence until 1 February 2024, which the Federal Aviation Authority (FAA) have targeted to complete a radio altimeter retrofit program.
Other countries such as France, Canada and Japan, have rolled out 5G with different mitigations. France currently operates 5G between 3.4–3.8 GHz ,while Japan operates up to 4.1 GHz.
In Australia, mid-band 5G has been operating since 2019 up to 3.7 GHz, and there have not been any confirmed reports of radio altimeter interference to date. Before 5G services, 4G technologies were used in the band from 2016.
How the ACMA is managing the issue
We collaborated with the telecommunications and aviation sectors in Australia to examine the issue further and determine how to achieve coexistence between 5G and radio altimeters.
We have worked with CASA to identify a precautionary approach to the deployment of WBB/5G services in the mid-band. There will be interim mitigations on new WBB deployments above 3.7 GHz until 31 March 2026, to protect against the risk of 5G interference with aircraft radio altimeters, which will allow the timely roll out of 5G services while providing time for the aviation sector to improve radio altimeter performance.
We have well-established practices to ensure that when new services are introduced into a spectrum band, the potential for interference with existing services is managed. These processes include closely engaging with all potentially affected parties, conducting appropriate technical studies and monitoring developments internationally.
