Mobile telephony without base stations

Natural disasters in recent years have shown how vulnerable our society is to unforeseen and disruptive events. At the same time we have seen that there is a strong will to help people in crisis areas. But for rescue operations to work, telecommunications need to be up and running.

Mobile telephone base stations and satellite telephones are of major importance, but they have their limitations in terms of cost, construction time, and access on a large scale. Mikael Asplund, a doctoral candidate in computer science, is now presenting, among other things, a complement to existing communication channels in a crisis.

The idea is to use the new generation of mobile phones to send messages directly from one phone to another. The advantage of this type of spontaneous network is that it can be used by everyone, without any special equipment, and it can be set up virtually instantly to solve problems that arise in a specific place.

But such networks bring not only great potential but also challenges, as gaps and network partitions can arise, so that nobody can forward a message. At the same time the use of batteries necessitates great energy efficiency. Mikael Asplund and his associates have designed a program that overcomes these difficulties when it is run on telephones, making it possible to deliver messages under extremely severe conditions.

The first part of the dissertation also deals with network partitions in a more controlled environment. This problem can arise, for example, when an Internet bank experiences disruptions in its network connection to other parts of the bank. The dissertation presents a method for the bank to continue to provide service to its customers despite such breakdowns.