Reliable Data Gathering in Tree-Based IEEE 802.15.4 Wireless Sensor Networks

This paper describes a routing protocol for enhanced robustness in IEEE 802.15.4-based sensor networks, which also addresses typical MAC layer issues, including power management, synchronization and link reliability. The algorithm uses a single-path strategy in error-free scenarios and resorts to using alternative paths when communication errors are detected. Our proposal exploits implicit acknowledgement of reception, a feature which may be provided by data aggregation when a broadcast medium such as the wireless channel is used. Therefore MAC layer acknowledgements are not used and errors recovery relies on a caching and retransmission strategy. The protocol requires synchronization among the nodes, which also allows the implementation of power saving techniques such as sleep/listen schedules. The performance of the proposed approach is evaluated through simulations, in which we study the overall network reliability and quantify the energy requirements, with different network sizes and protocol parameters.