In wireless sensor networks, a communication model that separate a sink collecting information from sensor nodes and a user using it has been proposed. In the model, a mobile user appoints a neighborhood sensor node as a dynamic sink, and the dynamic sink collects data from all sensor nodes and forwards the aggregated data to the mobile user. In this paper, we expand the model for single mobile user to support multiple mobile users. A core of the novel model is mapping between single dynamic sink and multiple mobile users. Namely, multiple mobile users appoint a dynamic sink and the sink collect information from all sensor nodes and forward them to the multiple mobile users. To design effectively the novel model, two issues should be solved. First, the multiple mobile users without any mutual communication channel should efficiently choose and appoint only one dynamic sink. Second, the single dynamic sink should forward the collected information to the multiple mobile users. This paper proposes a solution for those issues. The solution consists of three schemes: 1) data collection scheme, 2) tree-based multicast scheme, and 3) user mobility support scheme. The data collection scheme is to solve the first issue and the tree-based multicast scheme is to solve the second issue. Also, the user mobility support scheme is to guarantee data forwarding to mobile users.
