Optimised delay-energy aware duty cycle control for IEEE 802.15.4 with cumulative acknowledgement

IEEE 802.15.4 beacon-enabled mode adopts duty cycle to achieve energy efficiency and provides an optional acknowledgement (ACK) mechanism to ensure the transmission reliability. However, frequently sending ACK introduces additional ACK transmission energy consumption and increases end-to-end delay. In this paper, we focus on a duty cycle optimisation problem with joint consideration on energy efficiency, end-to-end delay and reliability for IEEE 802.15.4 networks. We first formulate a cumulative ACK enabled duty cycle optimisation problem as an inventory control problem. Then, the optimal solution to the problem is derived by applying dynamic programming (DP). Furthermore, a low complexity delay-energy aware duty cycle control (DE-DutyCon) is proposed to reduce the computational complexity of implementing the control on computation limited sensor devices. The joint-cost upper bound of DE-DutyCon is also provided. DE-DutyCon achieves an exponential reduction of computational complexity compare with DP optimal control. Simulation results show that the proposed DE-DutyCon achieves close performance in terms of energy efficiency, end-to-end delay and packet drop ratio compare with DP optimal control under various network traffic.