A Study of Near Ground Channel Model for 2.4GHz IEEE802.15.4 Signal in Outdoor Environment

Wireless Sensor Networks (WSNs) which consist of thousands of sensor nodes has become one of the most popular topics. As the deployment of outdoor wireless sensor networks continues to accelerate, it has been clear that a proper deployment may achieve both the sound networks performance and the low cost. A basic criterion for selecting nodes location is the path loss which has essential impact on the connectivity of the whole network. In addition, a correct path loss model is the prerequisite to obtain valid simulation results. This paper discusses several popular path loss models and takes measurements in different environment with real WSNs nodes based on MSP430 and CC2420. Linear regression is employed in data process to compare different models. The model parameters and fitting results are presented in this paper. The result shows that adopting some site-related information may improve the accuracy of path loss models.