A Residual Energy Aware Schedule Scheme for WSNs Employing Adjustable Awake/Sleep Duty Cycle

In this paper, we systematically analyze the relationship among expected energy expenditure, packet loss ratio, end to end delay and lifetime of wireless sensor networks. Firstly, we demonstrate that optimized duty cycle schemes can achieve a trade-off among the lifetime of network, transmission delay and packet loss ratio. Then, a residual energy aware with adjustable duty cycle scheme (READC) is proposed based on the fact that energy consumption is higher in the region near sink, while it is lower in the area far away from the sink. In READC scheme, sensor nodes near sink adopt appropriate duty cycles to meet with the requirement of forwarding data, while the higher duty cycles are needed in far-sink area. In this way, the residual energy of the nodes can be fully used. Meanwhile, transmission delay and packet loss ratio can also be reduced. Through our extensive theoretical analysis and simulation study, we demonstrate that compared with fixed duty cycle schemes, the READC scheme can reduce the transmission delay from 10.1 to 40.35 % and the packet loss ratio from 7.7 to 71.63 % without impacting the lifetime of network.