Optimal transmission policy with joint minimization on energy consumption and delay for wireless sensor networks

In wireless sensor networks (WSNs), periodically switching nodes into sleep mode is an effective way to reduce the energy consumption. However, the sleep period introduces additional end-to-end delay into packet delivery. We propose an optimal transmission policy, which assigns the number of packets per node should receive at each active period to minimize the end-to-end delay and the energy consumption. We formulate the problem as a classical inventory control problem with the aim of minimizing a joint-cost of energy consumption and end-to- end delay. By applying dynamic programming (DP), we derive an optimal transmission policy as the solution to the problem. Simulation results show that the proposed transmission policy can achieve about 50% reduction in both energy consumption and end-to-end delay as compared to that of IEEE 802.15.4.