Smartphones like stem cells: Cooperation and evolution for emergency communication in post-disaster scenarios

Spontaneous networks among end-user devices (e.g, smartphones, tablets) can guarantee emergency communication in post-disaster scenarios where the original infrastructure has been partially damaged by the occurrence of unpredictable or catastrophic events. However, the heterogeneity of devices and wireless access technologies poses important challenges on the network deployment and management. In this paper, we propose the STEM-Net architecture as a viable network model to handle the devices´ heterogeneity and to enable spontaneous networking functionalities in post-disaster scenarios. In STEM· Net, the wireless devices - called Stem Nodes (SN) - are able to adapt their transmitting configurations, cover different roles (e.g. router, bridge, etc) according to the system needs and evolve their functionalities through cooperation with other nodes. Here, we provide a proof-of-concept of the principles of nodes´ mutation and evolution, by discussing how heterogeneous end-user devices provided with SN capabilities can dynamically self-organize into multi-hop networks, and share the Internet access by switching among three roles: stub, transit and gateway SNs. A bio-inspired distributed gateway selection mode is proposed to allow each SN device to decide its current role, based on the system needs and on the individual hardware characteristics and resources (e.g residual energy or queue occupation). The simulation analysis conducted with the Omnet++ tool demonstrates the effectiveness of the STEM-Net framework in prolonging the network lifetime while providing adequate bandwidth for emergency communication to the end-users devices.