Upper 6GHz: A shared approach equals shared challenges

Spectrum is the lifeblood of mobile connectivity. It enables the wireless transmission between mobile devices and the nearby mobile masts, giving consumers and businesses access to the voice and data services that are so instrumental to our daily lives. With there being a finite amount of spectrum to go around, mobile operators have always had to be innovative with how they optimise the use of spectrum holdings to deliver the very best experience to customers. Since switching off our 3G network, for example, we’ve been able to re-farm some of that spectrum to add capacity to our 4G and 5G networks.

The value of U6GHz for mobile

Now, as we continue to progress with the rollout of 5G Standalone, we have to think about the next generation of spectrum – namely the upper 6GHz band – and how this is used to enable the very best digital connectivity across the UK. Different spectrum bands have different characteristics, meaning they’re suitable for differing use-cases – and it’s important that these are allocated and managed carefully so as to avoid interference with one another.

As the UK’s leading provider of both fixed and mobile communications services, we’re uniquely well-placed to understand where new spectrum is most needed to support wireless communications services – and it is our view that by dedicating the upper 6GHz spectrum to mobile networks, we can help to futureproof the reliability and consistency of 5G services as well as provide a strong foundation for 6G in the future.

While the mobile industry has made great progress in building and scaling connectivity across the UK, it is fair to say that with continuing growth in demand for mobile services, there is an ongoing need for advancements in this space, not least in indoor and crowded urban areas like stadiums and high streets – which is the sweet-spot of where upper 6GHz spectrum is most effective.

Demonstrating the challenges of a shared approach

However, in these same densely populated, high-demand areas, there is a high propensity that the proposed sharing of upper 6GHz spectrum between mobile networks and Wi-Fi could cause the respective channels to overlap. This would deliver both technical and operational challenges, resulting in a worst-of-both-worlds experience.

In a trial last week, we specifically demonstrated these challenges, working with Nokia to compare the spectrum’s performance for mobile use only versus when shared across mobile and Wi-Fi. In both indoor and outdoor environments, the results showed a severe impact on both mobile and Wi-Fi performance when both channels were active and overlapping – something which would be impossible to avoid in a busy urban environment.

This includes a reduction in mobile data rates of over 80 per cent, and in Wi-Fi of 90 per cent, when indoors. In some cases, both mobile and Wi-Fi connections were slowed down so much that they stopped working entirely for short periods. And even outdoors, where the impact was less severe, an active mobile device could still disrupt nearby indoor Wi-Fi data rates by more than 40%.

It therefore becomes clear why a shared approach is so problematic:

• Firstly, the majority of mobile data usage takes place indoors, and this is where the impact of sharing spectrum between mobile and Wi-Fi channels is most detrimental on user experience for both use-cases.
• Secondly, even if the mobile user is outdoors, with no desire or ability to login to a Wi-Fi connection, mobile use can still cause a negative impact to Wi-Fi users within properties – be it a coffee shop, office space or library – and at the same time the WiFi use within such venues can also interfere with the mobile network performance.

On a positive note, the testing also found that upper 6GHz spectrum performs favourably compared to the widely deployed 3.5GHz band when operating in similar physical and technical conditions, at various indoor and outdoor test locations. This demonstrates that it will be an important addition to enhance the capacity of current 5G networks, within which 3.5GHz currently provides a strong balance of coverage and capacity, as well as in enabling the timely introduction of 6G by leveraging the current cell site grid in urban and suburban environments.

A crucial decision for mobile connectivity

Trials like this underscore the critical importance of reserving the upper 6GHz band exclusively for mobile use. It’s essential to consider both the technical challenges of a shared approach, as well as the positive economic impact that this spectrum can deliver by unlocking the full potential of 5G, as well as laying the groundwork for an efficient and cost-effective 6G deployment. With Wi-Fi already benefiting from the lower 6GHz band, allocating the upper band to mobile ensures operators will be able to deliver long-term value for consumers, businesses, and national economies.

Read our whitepaper for more information on the trial and its conclusions.