A Practical Data Reporting Solution for Free-ranging Cattle Monitoring Applications Using Wireless SensorNetworks

摘要

This paper provides a study of the facilitating data communications for agricultural livestock monitoring applications using wireless sensor networks (WSNs) in a worst case case scenario: a relatively small number of cows distributed sparsely in an open field. Several design challenges are first indentified and analyzed in depth using actual GPS position data gathered from a farm trial. Two analysis metrics, Connection Availability and Connection Duration, are used to quantify impact of cattle movingbehavior and device duty cycle on network connectivity. Based on the results of this analysis, a practical communication scheme called Direcf Forwarding (DF) is proposed particularly for free-ranging cattle monitoring applications where communications take place in a non real-time manner. The proposed DF scheme has been implemented using the MICAz sensor node as a development platform. Farm trials have been carried out to study the network performance in terms of data delay, buffer utilization and received data rate. The results show that in the present extreme case, DF scheme has data delay of around an hour and thus real time communication is impossible. The results also show the reliability and robustness of this approach which achieves an expectedoperational lifetime of 2 years.