DTN-based data aggregation for timely information collection in disaster areas

When disasters occur, a common characteristic is the partial or complete failure of the telecommunications infrastructure so the usual means of communication are often not available. However, accurate and timely information of the disaster area is important. In this paper, a data collection method from an area of interest (AoI) within the disaster zone is proposed that uses the mobile phones of the people to serve as sensing nodes. To achieve maximum AoI coverage while minimizing delay, we propose a DTN-based data aggregation method. Mobile phone users create messages containing disaster-related information and merge them with their respective coverage areas into a new message with the merged coverage to reduce message size and to minimize the overall message collection delay. However, simply merging messages may result in duplicate counting thus, to prevent this, a Bloom filter is constructed for each aggregated message. Also, to reduce further the message delivery time, the expected time of a node to reach its destination is introduced as a routing metric. Through computer simulation with a real geographical map, we confirmed that the proposed method achieved a smaller delay in message delivery than epidemic routing.