Availability modelling of a virtual black box for automotive systems

Recent developments in automotive systems recommend storing historical information in a black box, in a manner that is similar to the avionics domain. The idea is to record relevant information about the vehicle that can be retrieved in case of a problem. However, instead of using a classical hardware based black-box that could induce a high cost, a more cost effective solution would be to use a software based mechanism that consists in storing the recorded data on a dedicated server at the fixed infrastructure. To protect the data against potential losses before an access to the fixed infrastructure is available, the data can be replicated and temporarily stored on neighbouring encountered vehicles using wireless communication technologies, before being permanently saved on the server. The aim of this paper is to analyse and evaluate the availability of the historical data recorded in the virtual black-box, (VBB) taking into account possible data replication strategies, and various mobility scenarios, using Stochastic Activity Networks (SAN).