Reliable, energy-aware cross-layer protocol for wireless sensor networks

This research addresses communication reliability in the highly constrained wireless sensor networks environment. We propose a cross-layer, reliable wireless sensor protocol design. The protocol benefits from the body of research in the two areas of wireless sensors reliability research and wireless sensors energy conservation research. The protocol introduces a new energy saving technique that considers reliability as a design parameter and constraint. The protocol also introduces a new back-off algorithm that dynamically adjusts to the data messages reliability needs. Other cross-layer techniques that the protocol introduces are dynamic MAC retry limit and dynamic transmission power setting that is also based on the messages reliability requirements.Cross layer design is defined as the interaction between the different stack layers with the goal of improving performance. It has been used in ad hoc wireless systems to improve throughput, latency, and quality of service (QoS). The improvements gained in performance come at a price. This includes decreased architecture modularity and designs may be hard to debug, maintain or upgrade.Cross-layer design is valuable for wireless sensor networks due to the severe resource constraints. The proposed protocol uses cross-layer design as a performance and energy optimization technique. Nevertheless, the protocol avoids introducing layer interdependencies by preserving the stack architecture and optimizes the overall system energy and reliability performance by information sharing. The information is embedded as flags in the data and control messages that are moving through the stack. Each layer reads these flags and adjusts its performance and handling of the message accordingly.The performance of the proposed protocol is evaluated using simulation modeling. The reference protocol used for evaluation is APTEEN. We developed simulation programs for the proposed protocol and for APTEEN protocol using the JiST/SWANS simulation tool.The performance evaluation results show that the proposed protocol achieves better energy performance than the reference protocol. Several scalability experiments show that the proposed protocol scales well and has better performance for large networks. Also, exhaustive bandwidth utilization experiments show that for heavily-utilized or congested networks, the proposed protocol has high reliability in delivering messages classified as important.