Cross-layer optimization for wireless sensor networks with RF energy transfer

Recently, radio frequency energy transfer (RFET) attracts more and more interests for powering sensor nodes in the wireless sensor network (WSN). In the conventional WSN where sensor nodes are powered by a small battery with finite amount of energy, reducing energy consumption of sensor nodes is of primary importance. On the contrary, in the WSN with RFET, since energy can be continuously supplied to sensor nodes, reducing energy consumption is not an important issue. However, in the WSN with RFET, the energy harvesting rate of each sensor node depends on its location, which causes the unbalanced available energy among sensor nodes. Hence, to improve the performance of the WSN with RFET, it is important to develop network protocols considering this property. In this paper, we study this issue with jointly considering routing, scheduling, and power control in the WSN with RFET. We obtain a solution for joint routing, scheduling, and power control considering unbalanced energy harvesting rates among sensor nodes, and show that our solution can improve network performance significantly.