Emergency network design - saving lives by saving power

In disasters and emergencies severity of trauma and loss of life can be reduced by more effective communication between emergency workers, volunteers, and survivors. Typically, almost all of these parties will hold mobile phones (in addition to special purpose wireless communication devices, in the case of emergency workers), which are likely to be used intensively to seek and to provide aid to those in need. However, the utility of mobile phones may be limited by battery life. The usefulness of these mobile phones can therefore be enhanced by extending battery life. One way to extend battery life is to introduce a duty cycle, i.e. a pattern of use where the phone is alternately sleeping and active. It is shown below that under some broad assumptions about the type of emergency, it is best to introduce such a duty cycle straight away, and to start with quite short sleep cycles, which increase exponentially, but with a relatively slow rate of growth of the sleep cycle duration. Simulation experiments are conducted below which demonstrate the effectiveness of this strategy.