5G indoors and how to fix it | Light reading

We all know the problem: Cell phone service works fine until you move indoors. Then, sometimes it works (you don’t notice), sometimes it somehow works (meh) and sometimes it just hangs on to a little bar or stops altogether (argh).

Diagnosing the problem is relatively simple. Loss of mobile service indoors is basically the result of outside-in coverage strategies and loss of building access (BEL), which is the attenuation of radio signals by walls and windows. This is particularly an issue for mid-band 5G frequencies (the main 5G band in most markets). At these frequencies, BEL is typically 2030 dB* (depending on building type). For users already nearing the edge of the outer cell, this amount of loss is enough to seriously degrade quality of service or completely shut down service as the user moves indoors.

Dealing with the problem is more difficult. There are a myriad of physical, commercial and technical factors that combine to make indoor 5G service a thorny problem to be solved nationwide. It’s certainly a technically solvable problem, there are many great solutions, but who pays and how to deal with the huge variety of buildings and places, their owners and tenants, remain major challenges.

The case for 5G indoors

Indoor coverage matters because we spend so much time indoors (apparently Americans spend an average of 87% of their time indoors**). A better experience for customers, with less frustration, certainly pays off. And in a business context, there is a direct line between good/poor mobile service and productivity.

There are also opportunities that rely on better indoor 5G service:

• Location and smart building services. Especially for larger and more prestigious venues, there are opportunities to integrate Wi-Fi (and other wireless technologies) to better support venue operations and the visitor experience across all types of venue services (security, signage , video monitoring, staff communications, point of sale, etc.). Stadiums and airports are the canonical examples.
• Combine private and public mobile network services. In many cases, there are more users for 5G headquarters connectivity. 5G technology allows public network customers and private network applications to run on a common infrastructure, for example, using separate network sections or discrete virtual networks to protect privacy and performance.
• Because it adds value to real estate. This is of direct interest to landlords, and logic inexorably leads to the conclusion that building owners should contribute to the financing of in-house 5G systems. Real estate developers are now very aware of this requirement. Existing building owners sometimes require more persuasion.

The good news is that there are multiple ways to deliver brilliant indoor 5G networks to industrial headquarters, campus networks, and all types of commercial buildings.

Because we shouldn’t worry too much

Indoor service has always been a problem and we live with that. Gradually, operators and building owners get busy fixing the places where there is the most demand and life goes on. It’s not great, but it’s okay. Incremental progress over a decade helps make a difference.

And there are other reasons why there’s no rush to tackle 5G indoors:

• Customers can switch to Wi-Fi. Wi-Fi is widely used and offers mostly great, sometimes brilliant performance. At home or in the office, it’s usually the primary option. Sure, it can be a pain to connect and a hit and miss experience away from trusted places. But if it’s available and we need it, we use it. And with automatic access to reliable Wi-Fi, these challenges can be alleviated to some extent.
• The task of retrofitting a building or location is costly and disruptive. The installation of cables, radio units and antennas is really the crux of why indoor 5G is such a difficult problem to solve. Outside of prestige venues, benefits are challenged by required capital investment and disruption, this argument argues. This business case is especially challenging if the site needs a different system for each operator.
• The low band can pick up the voltage. Operators can offload external 5G users to mid-band to free up their low bands for internal service. This is what operators rely on most of the time in most locations today. An excellent strategy but with limited bandwidth on low bands, it also reflects a limited ambition for better 5G services.

If the goal is to offer fantastic 5G services, it is clear that the industry should do more to improve indoor performance. The challenge is that the diversity of locations creates a fragmented market, and this is reflected in the different technical and commercial solutions available. I will elaborate on the key issues in subsequent blogs and research. Get in touch if you want to get involved.

The starting point is to argue why brilliant indoor 5G service matters and establish the intention to address it. Business models and technical solutions will then be presented.

* BEL of 2030 dB for midband spectrum is a rule of thumb based on several studies presented in ITU-Report P.2346-4, “Compilation of measurement data related to building entry loss”, last updated July 2021. Click here for more information.

** According to the oft-cited National Human Activity Pattern Survey by Neil E. Klepeis et al. (2001, page 239).

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