Delay-Tolerant Mobile Sensor Network (DTMSN) distinguishes itself from traditional Wireless SensorNetwork by several distinctive characteristics. Since end-to-end connections in DTMSN exist with certain probability, the conventional routing protocols for WSN may achieve poor network performance under these challenging scenarios. Hotspot-Based Adaptive Routing (HAR) is a routing scheme designed for DTMSN, which includes mobile-assisted carriers (MA) to help data delivery from nodes to sink and exploits the regularity of nodal mobility to guide the route design for MA.

In this paper, we present an improved routing scheme, named IHAR, based on HAR. In our scheme, several optimizations are employed to the original HAR to maintain less redundancy and better accuracy for hotspot selection. And the probabilities for different nodes to meet MA get balanced. The simulation results show that the proposed scheme outperforms the original HAR and adapts well under a variety of circumstances.