Stability of wireless networked control system using energy-efficient fuzzy based adaptive error control

In this paper, we investigate the performance of Wireless Networked Control System (WNCS) in an indoor environment, where often experienced high packet error rates negatively affect the control system stability. In such scenarios, low-power wireless communication among resource restricted distributed nodes (sensors, controllers and actuators) is heavily influenced by channel impairments due to movement of people, obstacles, or radio interferences. To remedy this, a novel Forward Error Correction (FEC) based adaptive error control mechanism is proposed that employs the cascaded fuzzy inference system to combat low-power communication unreliability. The strategy amalgamates three heterogeneous metrics such as signal-to-noise ratio, line-of-sight/non-line-of-sight detection and ACK/NACK count to closely estimate the radio links´ quality and applies it to select an appropriate FEC code to protect packet transmissions. Extensive numerical evaluations are carried out for WNCS using a realistic indoor fading model and IEEE 802.15.4 2.4 GHz modulation format. The proposed adaptive scheme not only depicts good trade-off between packet error rate and energy efficiency, but also guarantees WNCS stability deployed in indoor spaces.