A significant number of promising wireless sensor applications for the Internet of Things (IoT) are becoming a reality. Most of these applications require a variety of heterogeneous and geographical sensor data to be delivered to users such as mobile devices, vehicles, and cloud systems for big data analysis to extract maximum value from the physical world. Data caching of popular data items in a network can significantly improve efficiency and reliability of content delivery by contributing the reduction of data access delay, bandwidth usage, and packet losses in resource-limited low-rate wireless sensor networks. In this paper, we propose an efficient cache placement protocol (BCDA) that minimizes data access cost and guarantees cache consistency in a lightweight manner. The BCDA decides where to store a copy of data content in a network using a distributed approach according to clients' access patterns, memory capacity, data size, and so on. To evaluate the feasibility and effectiveness, we implemented the BCDA in ns-2 and compared its performance with existing caching strategies. The simulation results highlight that the BCDA significantly reduces data access cost with minimizing cache management cost.
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