Scalable and efficient data delivery protocols for wireless sensor networks

Wireless sensor networks (WSNs) can provide broad applications, including hazard detection, structure monitoring and geographic security. However the resource constraints of sensor nodes make protocol designs of WSN applications incur many challenges such as energy efficiency, scalability, and system complexity. Particularly, energy efficiency has been treated as the most fundamental design issue of protocols for WSNs.This dissertation focuses on both energy- and latency-efficient protocol designs at MAC and routing layers for multi-hop WSNs. At MAC layer, we adopt hybrid design mechanisms to improve the energy efficiency of MAC protocols while still providing comparable latency performance. At routing layer, we focus on developing a scalable and efficient location-aided data forwarding protocol to reduce the communication overheads needed for table-driven routings and hence the energy consumption.Furthermore we consider cross-layer designs to improve the performance of protocols for WSNs. We observe that existing energy efficient MAC designs tend to incur high end-to-end message delivery latency in multi-hop routing scenarios. Based on this observation, we address how to provide routing layer coarse-grained end-to-end quality of service (QoS) support at MAC layer for time critical WSN applications. We also propose a cross-layer solution between MAC and routing layer to minimize the per-hop data delivery latency in location-aided data forwarding protocol and hence improve the energy performance.