Abstract
Search and rescue are important issues for mountain hikers. In this thesis, we assume that every hiker carries a wireless sensor node with GPS receiver. When hikers meet in mountains, their sensor nodes can exchange the locations of each other. To save nodes energy, energy efficiency protocols usually make idle nodes sleep to achieve power conservation. However, protocols that make idle nodes sleep may sacrifice tracking quality of the tracking systems. In this thesis, we propose two energy efficiency protocols to solve this problem. In the first protocol, we choose node that has the most numbers of neighbors in a group to become the group leaders and make group members go into sleep mode to save energy. In addition, several small groups can be concatenated as a large group to save more energy. In the second protocol, we consider the relative moving speed between nodes to reduce their power consumption. A node can go into sleep mode and wakeup to exchange location information with its neighbors only at the moment that the neighbors will leave the node’s communication range. The simulation results show that our protocols can reduce energy consumption of nodes with acceptable tracking quality.