Energy-Efficient Data Forwarding for State Estimation in Multi-Hop Wireless Sensor Networks

State estimation is of great importance in various applications based on wireless networked control systems. Wireless sensor node usually forwards its data to a remote receiver through a series of relay nodes in order to save its limited energy. In this technical note, we investigate the data forwarding strategy design for accurate remote state estimation in multi-hop wireless networks. Based on different computational capability of relay nodes, we first propose two relay strategies, namely, Direct Forwarding Strategy (DFS) and Local Processing and Forwarding Strategy (LFS). Stability condition, estimation performance and energy efficiency of both the two strategies are theoretically analyzed. We further propose an Event-triggered Forwarding Strategy (EFS) which is able to balance the estimation accuracy and relay energy consumption. Numerical examples are employed to demonstrate the effectiveness of our design.