Infrastructure-free communication means being able to communicate without relying on a base station or an internet connection that has to stay up in the field. Wherever the network has collapsed or was never built, it is what lets team members reach each other. In this post we look at three ways of doing it: satellite, radio and mesh networks.
Everyday communication rests on a chain
The phone in your pocket does not talk to anyone on its own. It connects to the nearest base station, and the real work happens in the infrastructure behind that station. The station needs power to run, and a transmission link to the backbone, known as backhaul, to reach the rest of the network.
That is a chain, and every link in it has to stay up. If the power fails and backup power runs out, if the backhaul is cut, or if the station is damaged, the phones attached to it go quiet. Even two people standing side by side cannot message each other, because their messages first have to pass through that chain.
Infrastructure-free communication sets out to remove that dependency: devices either talk to each other directly or communicate along a path that does not use the infrastructure in the field at all. That does not mean no technology is involved; it means communication does not depend on a fixed component in the field that has to stay up. It is also what we mean when we talk about communicating without a network or without internet.
Why it is needed: disasters and field work
Infrastructure-free communication is needed most when the chain breaks. An earthquake, flood or fire can cut a base station's power and its backhaul at the same time. Backup power only lasts for a limited time. And everyone loads onto the stations still standing at once; even if the network is technically working, calls may not connect and messages may not get through.
Yet the first hours of a disaster are when communication is needed most: search and rescue teams spread across the field, and the coordination centre needs to know who is where. We describe how that gap is closed in the field on our disaster and emergency communication page.
The second case is quieter: sites where the network is missing or not enough. Rural and mountainous terrain, forests, the corridors that power lines run through, mines and construction sites are often places where coverage is weak or absent altogether, and inside industrial plants metal and concrete cut the signal too. At crowded events the network is there, but it can become congested.
That is why the question to ask in a disaster plan, or when preparing for field work, is not when the network will come back but which system will work while it is gone. Our note on post-earthquake emergency communication answers that question step by step.
Three approaches: satellite, radio and mesh
There is no single way to communicate without infrastructure. Each of the three approaches below is strong in some places and struggles in others.
Satellite
Satellite communication does not depend on base stations on the ground; the terminal talks directly to the satellite. So it can keep working when the network in the area collapses, and it is a strong option for reaching a distant centre.
That comes at a price. Each terminal is a separate device and often a separate subscription. The terminal has to see the sky; indoors, in a deep valley or under dense tree cover the connection becomes harder. Terminals do not carry each other's messages, so a team member without access to a terminal is left outside the link.
Radio
Two-way radios can talk to each other directly; this is the most familiar form of infrastructure-free communication, and a strong tool for instant voice coordination.
But radio is voice-centric. The speaker occupies the channel, anyone not listening at that moment can miss the message, and on a noisy site what was said can be misheard. Range is limited by the radio's power, its antenna and the terrain; reaching further means installing repeaters and, in many bands, obtaining a frequency allocation.
Mesh network
In a mesh network, devices connect to each other rather than to a centre, and carry each other's messages. The difference from radio is that no separate repeater is needed to extend the range: every device that joins is also a relay. As the team spreads across the field, the devices in between carry the signal and the covered area grows.
To help weigh which approach suits your site, we have gathered the technical criteria to ask about (frequency band, range, hop count, setup time and infrastructure dependency) in a single table in our field communication system buyer's guide.
Mesh networks in brief: a message hops from device to device
The idea behind a mesh network is simple: everyone both talks and carries what others said. Each device sends its own messages and also moves the messages of the devices around it one step further. A message jumps from device to device until it reaches its destination; this is called hopping. So two people who are not within direct range of each other can communicate through the devices in between.
Because there is no centre, a single failure does not silence everyone. If a device runs out of battery or moves out of range, the message goes around it, as long as another path exists. When a team member moves or a device is switched off, the network reorganises itself; nobody has to change a setting.
We explain how it differs from a centralised network, and how hopping works, with diagrams in our post on mesh networks.
The BosNets approach: internet where there is coverage, mesh where there is not
At BosNets we do not see the mobile network as a rival; when it is there, we use it. Where there is coverage, the phone connects straight to the BosNets server; messages, positions and task assignments sync in real time and the range limit disappears. When coverage runs out, the same message moves onto the mesh through the BosMag beside the phone. The switch is automatic: the user changes no settings, and the app and the conversation stay the same.
On the mesh side, the work is done by BosMag. Smaller than a wallet, the device attaches to the phone with a magnetic holder and pairs with BosApp over Bluetooth; the devices talk to each other over radio frequency. It provides 5 km of range on a single hop in open terrain and 2 km in urban areas. Because the devices run on the licence-free 869.4–869.65 MHz band, no frequency allocation is needed, and they need no internet, SIM card or satellite link. Location does not come from the network either: the built-in GNSS sensor produces position without needing a network, and BosApp's offline map, downloaded in advance, opens without internet.
When coverage returns, everything that happened on the mesh in the meantime syncs with the server, so time spent outside coverage leaves no gap in the record. Having just one person in the team inside coverage also helps: their phone becomes a bridge, carrying the messages of the team outside coverage onto the internet. That way the coordination centre is not left blind when the team moves out of coverage. We explain the two modes and how the bridge forms in hybrid and bridge communication.
The limits: a mesh network is not magic
A mesh network is not a magic solution, and its limits are worth knowing from the start.
First, without anyone in between there is no hop. Where there is no network, if someone falls far behind the team and moves beyond the range of the nearest device, communication stops. The gap is closed either by the devices of team members in between or by a BosBase relay station placed at a high point. Drawing its power from the sun, BosBase reaches 20 km with its larger antenna.
Second, range changes with the terrain, and the chain does not stretch forever. The figures we give for BosMag are single-hop range; dense structures, rubble and deep valleys reduce that distance. In BosNets a packet is also carried across at most five hops, a limit that prevents copies circulating in the network forever. We describe the mechanism in our piece on the tactical mesh network.
Third, radio frequency does not carry unlimited data. The BosNets mesh is designed to carry written messages, locations and status information, not video streams.
Finally, the devices have a battery life too. Under normal field use BosMag stays active on the network for 48 hours; sustained heavy message and location traffic shortens that.
Frequently asked questions
Does a satellite phone count as infrastructure-free communication?
Because it does not depend on the base stations in the area, it can keep working when the network collapses; in that sense it is one way of communicating without infrastructure. But it needs a terminal with a view of the sky, and often a subscription. Terminals do not carry each other's messages; in a mesh network, by contrast, devices connect to each other and the devices in between carry the message.
Does a mesh network replace two-way radio?
Not in our approach. Radio carries voice in the moment; BosNets carries written messages, locations and status information. We designed the system not to replace voice radio but to carry the data radio cannot: written instructions, live location, emergency alerts and a record.
Do you need a frequency licence or a line subscription?
It depends on the system; radio systems on licensed bands need a separate application for a frequency allocation. BosNets devices operate on the licence-free 869.4–869.65 MHz band, so no frequency allocation or licence fee is required. In mesh mode no SIM card, internet or satellite subscription is required either.
How does BosNets work when internet is available?
Where there is coverage, messages travel over the internet and the range limit disappears; when coverage runs out, the same message is carried over the mesh network. The switch is automatic and the user changes no settings. When coverage returns, everything that happened on the mesh in the meantime syncs with the server.
Conclusion
Infrastructure-free communication is not there to replace the mobile network but to cover the moment when there is none. Satellite stands out for reaching a distant centre, radio for instant voice coordination, and a mesh network for the written messages, locations and status updates within the team itself. At BosNets we chose to use the internet when it is there, and the mesh network the devices build among themselves when it is not.
If you would like to work out together which approach would work on your team's sites, write to us.