FWA (Purpose-built) vs Mobile (Multi-purpose)

Lately, I have been asked about how a 3GPP based Fixed Wireless Network could support some Mobile use cases, as for example, and the most obvious, incoming mobile roaming agreements?

I would say, the main difference between an FWA network and a mobile network, even if they are using the same spectrum, the same vendors, is the fact one is built for FWA while the other is built for many different use cases, and it happens that FWA can be one of the use cases supported, but a mobile network is designed for much more:

1. Mobility (Support features like hand over, ubiquitous coverage, etc.)
2. Indoor coverage (Support outside to inside coverage, on low bands, or purpose-built indoor coverage)
3. IoT coverage (Support NB-IoT, or CAT-M devices)
4. Roaming (Support required roaming interfaces, passed by roaming agreements/tests, offer 911/Voice services, etc.)
5. 3GPP based voice services (Support either CSFB for legacy voice, or VoLTE or VoNR)

While when we build an FWA network, we are focused on the best performance possible for stationary users, the FWA high gain antenna devices, which can be installed outside street level, rooftop, or even on small mast extenders like residential towers.

I tried to create an image that could help to visualize what I was saying, as you can see when you are building a mobile network, the investment is higher, not only because of the special mobility features, but also because you will need more sites, you may need to build multi-band sites, and you need to be more careful about what are the requirements of a mobile core.

So, I would like to conclude, while a Mobile network could eventually use spare capacity to offer FWA services, an FWA network may need a lot of upgrades to offer basic mobile services such as Roaming and this needs to be considered during the business strategy conversations.