When we talk about wireless we often associate it to “mobile”. Sometimes we actually talk about a “mobile infrastructure” although current wireless infrastructures are not mobile at all! They are made of towers rooted in concrete, connected by cables running in trenches underground to buildings where the switches are hosted. There is nothing mobile!
The fact that the wireless infrastructure is “fixed” makes life easier. The only things that move are the terminals (the cell phones) and the network keeps track of their location to route the call appropriately.
There are, however, other ways to create a wireless infrastructure. Airplanes are talking one another (sometimes directly, sometimes bouncing the communications from one plane to another) as they move in the sky. Buses in Oporto, Portugal, have become mobile network nodes providing WiFi connectivity to their passengers. Taxis in many cities around the world are now providing WiFi services to their passengers as well.
These mobile infrastructures continually change their links among the nodes in the network. As a node (a bus) gets too far from a fixex network access or from the bus with which it was connected the connection is lost. However, the connectivity service is not lost since there will be another fixed access point or another bus nearby that will pick up the connection.
These are Meshed Networks and they provide a tremendous flexibility. To work they need to have a sufficient number of network nodes, making sure that the overall network maintains the connectivity.
In Meshed Networks, the more nodes are present the better the connectivity and its resilience. Now, just imagine to have, as network nodes, the terminals, the cell phones.
In today’s wireless infrastructures the more cell phones populate an area served by an antenna the less bandwidth will be available to each one of them (if they are starting to use the network at the same time). That is obvious: the antenna capacity is getting divided by the number of users. Not so in a meshed network. The more cell phones you have in a given area the more communication capacity you have available since any new cell phone adds to the oveerall capacity.
The question is whether this is actually feasible. Well, this is becoming more and more feasible thanks to Moore’s Law and the increase in processing capacity letting a cell phone to manage more and more spectrum and to the decrease in power consumption that allows the cell phone to become a network node serving other phones without running out of battery.
This is something that needs to be leveraged by Smart Cities: use as much as possible its “users” as “providers”. As we will see, this does not just apply to communications infrastructures but to data and services as well.