In this work we present an obstacle-aware human mobility model for ad hoc networks. Typical examples where the nodes of mobile ad hoc networks are human-operated are natural or man-made disasters, military activities or healthcare services. In these scenarios, obstacles are an integral part of the areas where such networks are deployed in order to facilitate communication among the firemen, policemen, medics, soldiers, etc. In the proposed mobility model, the nodes of the network move around the obstacles in a natural and realistic way. A recursive procedure is followed by each node according to which every time an obstacle is encountered between the node's current position and the final destination point, the node moves to the obstacle's vertex that is closest to the destination. This process is repeated until the destination is reached. The obstacles are also taken into account in modeling the signal propagation. When a packet is transmitted through an obstacle, the power at which it is received is attenuated by a certain value representing the physical layer phenomena suffered by the signal. The model is implemented as an add-on module in Network Simulator ns-2. A thorough simulation study conducted highlights the differences of the proposed model with other mobility models, by investigating the properties of the resulting network topologies and their impact on network performance.

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In this paper we present a mobility model for ad hoc networks operating in mission critical situations, like for example natural or man-made disasters, military activities or emergency healthcare services. The proposed model captures the properties of mobility in situations like the above by incorporating hierarchical node organisation, typical for such scenarios modes of node activity, event-based destination selection and presence of physical obstacles that affect both the node movement and the signal propagation. The nodes are divided into groups with each group leader responsible for choosing the destination points. These choices resemble the events that occur in the network deployment area and the corresponding missions that are assigned to the node groups. The proposed model includes two modes of node activity that represent the two types of nodes primarily comprising such networks: the emergency workers and the medical staff. Each event belongs to a certain class, according to which reinforcements are called to provide further assistance. The conducted simulation study highlights the differences between the proposed model and other mobility models, by investigating their properties in terms of the resulting network topology and their impact on the performance of an ad hoc network operating under a well known routing protocol.