Adaptive coordinator switching scheme for mobile sensor networks
Faculty of Computing, Health and Science
School of Engineering / Centre for Communications Engineering Research
In the IEEE 802.15.4 standard for wireless sensor networks (WSNs), the coordinator switching process is initiated based on the link quality indicator (LQI) value of beacon frames when the mobile sensor node is at the edge of its current coordinator coverage range. Switching based on a fixed LQI threshold value is not suitable for scenarios where the mobile sensor nodes move at high speeds and the interval between received beacon frames is large. Due to low coordinator coverage in WSNs, such switching schemes often cause frequent sensor node disconnection because by the time a high speed mobile node realises that it is at the end of its current coordinator coverage range, it does not have enough time to start searching for a new coordinator and complete the switching process. To address this problem, this paper proposes a new scheme that triggers the coordinator switching process based on an adaptive LQI threshold. In this scheme, the LQI threshold value is computed to match the current beacon interval and speed of the mobile node. Simulation results confirm that the proposed scheme significantly increases mobile sensor node connectivity periods compared to the current IEEE 802.15.4 standard.