An experimental study of WSN transmission power optimisation using MICAz motes

Adjusting nodes positioning to satisfy the needs of network connectivity and power conservation in wireless sensor networks (WSN) is not a trivial task. Too far node distance may result in unreachable transmission while too near node distance not necessarily guarantee nodes connection. By knowing an acceptable distance range to position nodes in the networks, it can greatly help researchers to better configure settings of WSN environment, while reducing precision of readings between real WSN testbed and the simulation counterpart. This paper demonstrates a real implementation of transmission power control to assist the decision-making on nodes positioning to be used in a sensor network communication. The implementation of the study is done using the MICAz motes with a nesC programming in TinyOS in an indoor environment. Our findings suggest that to assure network connectivity, motes must not be located more than 1.18 metres distance when they are placed on the floor building and not more than 2.37 metres distance when they are situated about one metre above the floor building. Our results also indicates that the maximum length the signals can travel using maximum power 0 dBm is merely about six metres long.