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RF channel modelling and multi-hop routing for wireless sensor networks located on oil rigs

This study presents a combined analytical and empirical model for predicting the signal loss effects of metallic drilling rig structures on radio-frequency electromagnetic waves used by wireless sensor networks (WSNs) installed on a drilling rig. The model is based on the combination of free space path loss and the excess loss caused by the metallic structure separately. The authors combine both losses to predict the overall loss of signal strength. The model has been validated against field data collected from multiple drilling rigs. Further modification of the model to include the effects of different signal frequencies is under way. They present simulation results from OMNeT++ based on their model, to establish the packet loss and energy consumption expected for a real WSN. They also present a novel dynamic multi-hop routing protocol, which improves network performance by removing the constraints of single-hop forwarding. The algorithm directs packets to their destination via a selected node within a routing ‘cluster’. By combining their channel model and routing protocol, they are able to achieve 100% packet success, while setting transmit power levels appropriately to achieve the longest possible network lifetime.