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Indoor 5G and how to solve itIndoor 5G and how to solve it

The good news is there are many ways to deliver brilliant indoor 5G networks to industrial venues, campus networks and all manner of commercial and public buildings.

Gabriel Brown

May 30, 2023

5 Min Read
Indoor 5G and how to solve it

We all know the problem: mobile phone service is working fine … until you move indoors. Then, sometimes it works (you don't notice), sometimes it sort of works (meh) and sometimes it clings on by one tiny bar or drops out entirely (argh).

Diagnosing the problem is relatively simple. The loss of mobile service indoors is fundamentally a result of outside-in coverage strategies and building entry loss (BEL) — i.e., the attenuation of radio signals due to walls and windows. This is particularly an issue for 5G mid-band frequencies (the main 5G band in most markets). At these frequencies, BEL is typically 20–30 dB* (depending on building type). For users already toward the outdoor cell edge, this amount of loss is enough to seriously degrade service quality or block service entirely as the user moves indoors.

Addressing the problem is harder. There are myriad physical, commercial and technical factors that combine to make indoor 5G service a knotty problem to solve on a countrywide basis. It is certainly a fixable problem technically — there are several great solutions — but who pays and how to deal with the sheer variety of buildings and venues, and their owners and tenants, remain big challenges.

The case for indoor 5G

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

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

  • Venue and smart-building services. Especially for larger, prestige venues, there are opportunities to supplement Wi-Fi (and other wireless technologies) to better support venue operations and the visitor experience through all manner of venue services (safety, signage, video monitoring, staff comms, point of sale, etc.). Stadiums and airports are the canonical examples.

    • To combine private and public mobile network services. In many cases, there are multiple users for 5G venue connectivity. 5G technology enables public network customers and private network applications to run on common infrastructure — for example, using separate network slices or discrete virtual networks to protect privacy and performance.

      • Because it adds value to real estate. This is of direct interest to landlords, and the logic leads inexorably to the conclusion that building owners should contribute funding to indoor 5G systems. Real estate developers are now very aware of this requirement. Owners of existing buildings sometimes take more persuading.

    The good news is there are several ways to deliver brilliant indoor 5G networks to industrial venues, campus networks and all manner of commercial buildings.

    Why we shouldn't fret too much

    Indoor service has always been a problem, and we live with it. Gradually, operators and building owners get around to fixing the locations where there is the most demand, and life goes on. It is not great, but it's OK. Incremental progress over a decade adds up to make a difference.

    And there are other reasons why there is no rush to address indoor 5G:

    • Customers can switch to Wi-Fi. Wi-Fi is widely deployed and offers mostly great, and sometimes brilliant, performance. At home or at the office, it is typically the primary option. Sure, it can be a hassle to connect and a hit-and-miss experience away from trusted locations. But if it is available and we need it, we use it. And with automated login to trusted Wi-Fi, these challenges can be assuaged to some degree.

      • The task of retrofitting a building or venue is expensive and disruptive. Installing cable runs, radio units and antennas is really the crux of why indoor 5G is a hard problem to solve. Outside of prestige venues, the benefits are challenged by the required capital investment and disruption, runs this argument. This business case is especially challenging if the venue needs a different system for each operator.

        • Low-band can pick up the strain. Operators can offload outdoor 5G users to mid-band to free their low-bands for indoor service. This is what operators rely on most of the time in most locations today. A fine strategy — but with limited bandwidth on low-bands, it also reflects a limited ambition for better 5G services.

      If the objective is to offer fantastic 5G services, it is clear the industry should do more to improve indoor performance. The challenge is that the diversity of venues makes for a fragmented market, and this is mirrored by the diverse technical and commercial solutions available. I'll dig into the key issues in later blogs and upcoming research. Get in touch if you want to become involved.

      The starting point is to make the case for why brilliant indoor 5G service matters and establish an intent to address it. The commercial models and technical solutions will then present themselves.

      * BEL of 20–30 dB for mid-band spectrum is a rule of thumb based on numerous studies presented in ITU-Report P.2346-4, "Compilation of measurement data relating to building entry loss," last updated in 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).

About the Author(s)

Gabriel Brown

Principal Analyst, Heavy Reading

Gabriel Brown's coverage at Heavy Reading focuses on wireless data networking technologies, including 3G/HSPA, WiMax, and LTE, with a specific focus on how these technologies impact the wider mobile Internet services market. He has covered the wireless data industry since 1998, previously as Chief Analyst of the monthly Unstrung Insider, published by Heavy Reading's parent company Light Reading. Before moving to Heavy Reading, Brown was additionally responsible for the overall editorial planning of Light Reading's entire line of Insider research newsletters. Prior to joining Unstrung, Brown was the editor of IP Wireline and Wireless Week at London's Euromoney Institutional Investor. He often presents research findings at industry events and is regularly consulted by wireless networking technology leaders. He is based in the U.K.

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