This document summarizes a research paper on using mobile communication to improve energy efficiency in data-intensive wireless sensor networks. The paper proposes using mobile relay nodes that move to optimize positions for transmitting data from sensor sources to a base station. An algorithm is presented that iteratively relocates the mobile relay nodes to minimize the total energy used for both wireless transmission and node movement. The algorithm finds optimal positions for relay nodes within a fixed routing tree topology without changing the tree structure. This approach aims to reduce energy consumption in a holistic way compared to other mobility approaches.