DGR： dynamic gradient-based routing protocol for unbalanced and persistent data transmission in wireless sensor and actor networks

This paper is concerned with the routing protocol design for large-scale wireless sensor and actor networks （WSANs）. The actor-sensor-actor communication （ASAC） strategy is first proposed to guarantee the reliability of persistent actor-actor communication. To keep network connectivity and prolong network lifetime, we propose a dynamic gradient-based routing protocol （DGR） to balance the energy consumption of the network. With the different communication ranges of sensors and actors, the DGR protocol uses a data load expansion strategy to significantly prolong the network lifetime. The balance coefficient and the routing re-establishment threshold are also introduced to make the tradeoff between network lifetime and routing efficiency. Simulation results show the effectiveness of the proposed DGR protocol for unbalanced and persistent data transmission.