Indoor coverage 2.0: working together on in-building communication services on campus

Blog series: the unwired campus of the future

Institutions need to work together closely in order to keep offering users the same familiar communication facilities that they are used to, anywhere and any time. In the first blog post of this series, I looked in depth at the reasons for, and the most important components of, the unwired campus of the future. This time I will discuss the frequently used term ‘indoor coverage’, which originally referred to the ability to make in-building mobile calls. However, establishing this, for example by installing a DAS (Distributed Antenna System), is relatively expensive and time-consuming. Should we continue to focus on this given the decreasing importance of calls, which can easily be made via the Internet? Should indoor coverage not be viewed from a broader perspective?

Separate infrastructure only for calls?!

With fixed telephony on campus, we are already accustomed to making calls via the Internet. For mobile calls, this is not yet the case. Indoor coverage is being established on many campuses for this purpose. Indoor coverage means that there are in-building facilities for making 2G or 3G mobile calls, such as separate copper infrastructure throughout the whole building that is accessed via a mobile provider. Without these facilities, users of this provider would not be reachable on their mobile number in the well-insulated campus buildings, with their solar coatings on the windows. Dependence on the traditional form of indoor coverage for the ‘voice’ application is still significant: students, lecturers, staff and researchers want to be able to make mobile calls easily without the hassle of smartphone apps or coverage problems.

However, in education and research, establishing indoor coverage regularly results in substantial investments that only offer a partial solution. Indoor coverage is often included in tenders for mobile telephony subscriptions for staff. That may seem logical, but is in fact not: you invest in coverage for only 1 provider, which is of no use to visitors, students or staff who have a subscription with another provider. In addition, you purchase something that you can no longer use fully or even at all after an average contract term of 4 years (if you switch to another provider after a new tender).

So is calling via the existing Wi-Fi network the ultimate solution? Functionally, yes, but from interviews I’ve held about the unwired campus, institutions are not confident that ultimately, the quality and control options offered by Wi-Fi will be sufficient to make calls reliably. In addition, there is often emphasis on the need for a wireless backup, contingency or priority network in case the Wi-Fi fails or is congested. That is also one of the reasons why DAS is still being considered, although it should be noted that it is not the most ideal solution, as outlined above.

Market development and trends

Fortunately the market for in-building coverage is moving forward: a number of institutions and companies are now able to establish indoor coverage. Examples of this are ‘neutral host DAS’ solutions, where a neutral DAS is built for several providers, if, of course, they are willing to work together. In the longer term, centralised radio access networks (C-RAN) could be an option for more efficient in-building coverage.

However, this assumes the continuation of indoor spectrum which is nationally allocated to a provider for several years. This offers little scope for tailored solutions, which we expect will be much-needed on campus in future.

A development that is perhaps more attractive for the campus is the option of sharing spectrum based on time and location. Partly through shared spectrum being made available in the United States, this method has been implemented in practice and products have become available (see for example: These products transmit their geographical location and ensure that they do not use any frequencies that are allocated to others. A neutral host is also required here: an actor providing a gateway for unwired connections. This role can be fulfilled by sharing spectrum according to a specific policy and/or connecting parties with each other. This technology could also be utilised in the Netherlands in the short term: the 2.3 and 3.5 GHz bands can be used for this purpose.

In-building communication services instead of indoor coverage

But which technologies do we need to invest in now for the campus? Telecom providers aren’t very motivated to invest in voice infrastructure within their network: users pay for data, but nowadays, voice is a ‘free’ extra. The trend towards communicating via Internet applications such as WhatsApp and Skype has been evident for several years. These applications are known in the telecom world as over-the-top (OTT) applications, much to the incomprehension of the Internet world, but we will leave that aside for now. Is it actually logical for an ICT service provider on the campus to purchase, set up, maintain and constantly upgrade infrastructure with mobile calling for users as its sole purpose?

The answer is, of course, no. Nevertheless, in addition to voice, in-building mobile networks can also be used to provide many other services, currently virtually ignored. We should therefore abandon the term ‘indoor coverage’. Indoor coverage for voice is only a small component of unwired services as a whole. That is why we should focus on the full range of possibilities and technology for in-building communication services, not just on voice and Wi-Fi. That way, we can better fulfil the needs of the user and their devices, sensors and applications.

The most important topics identified here are:

  • Radio spectrum: licensed and unlicensed radio spectrum with (time- and location-based) in-building frequency/frequencies;
  • Capacity: the range of the active and passive radio cells and access points belonging to the spectrum, along with the actual bandwidth in relation to the number of active simultaneous connections. Also dependent on the backbone of the supporting fixed network;
  • Network technology: for example LTE (4G/5G), Wi-Fi, Li-Fi, private LTE and MulteFire for high data transmission and/or, for example, LoRa and BLE for IoT-type functionality;
  • Continuity: the availability of an infrastructure that can set traffic priorities and is not dependent on 1 platform or technology;
  • Accessibility: having secure, simple access to this infrastructure (for example using the E-SIM or accessing IoT databases via federated authentication systems such as SURFconext);
  • The service provider(s), providers and costs versus functionality. Who will ensure that this need is met efficiently? What role will SURF play and how will collaboration take place?

Ultimately we must find the right combination of the above topics. There is no simple solution possible with only 1 Wi-Fi or 5G infrastructure. Diversity is becoming the standard, and this will need to be managed properly. Institutions will have to expand their in-building communication services and continually adapt them to the users’ needs. Furthermore, they must join forces with other institutions to avoid constantly reinventing the wheel.

Joint strategy

In these times, where institutions in particular need to reduce costs and workload, attention and investment are required to ensure a suitable, future-proof unwired infrastructure on campus. The infrastructure must be designed uniformly across the campuses in order to realise the vision of education and research of the future. In doing so, we will have to determine which components of that infrastructure are of strategic importance for the institution and must be managed or owned by it. That way, we ensure long-term continuity. So which parts or assets have to be taken into account? One example is the right to use and control in-building frequencies, giving certain research traffic priority, for example. Others are the coverage and unlimited capacity of the network and uniform, secure authentication and authorisation for the network infrastructure.

We can only organize that in a future-proof manner through close cooperation with each other, spectrum regulators, telecom providers, service providers and hardware suppliers. We are therefore consulting with institutions and market participants to create a better picture of the playing field and possibilities as well as the (strategic) role of SURF therein. Do you want to contribute to the discussion on in-building communication services and the design of the unwired infrastructure for this on campus? Great! Please leave a comment using the form below, or contact me directly at

Read part 1 of this blog series: Radical changes needed in campus ICT services



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